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Paris saponin-induced autophagy promotes breast cancer cell apoptosis via the Akt/mTOR signaling pathway
Abstract
Paris saponins possess anticancer, anti-inflammatory, and antiviral effects. However, the anticancer effect of Paris saponins has not been well elucidated and the mechanisms underlying the potential function of Paris saponins in cancer therapy are needed to be further identify. In this study, we report that saponin compounds isolated from Paris polyphylla exhibited antitumor activity against breast cancer cell lines, MCF-7 and MDA-MB-231. Paris saponin XA-2 induced apoptosis in both cell lines, as evidenced by the activation of caspases and cleavage of Poly (ADP-ribose) polymerase. The ability of XA-2 to induce autophagy was confirmed by acridine orange staining, accumulation of autophagosome-bound Long chain 3 (LC3)-II, and measurement of autophagic flux. XA-2-induced autophagy was observed to promote apoptosis by the combined treatment of breast cancer cell lines with XA-2 and autophagy inhibitors 3-methyladenine and bafilomycin A1, respectively. Moreover, we report a decrease in the levels of Akt/mTOR signaling pathway proteins, such as the phosphorylated forms of Akt, mTOR, P70S6K, and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1). Taken together, these results provide important insights explaining the anticancer activity of Paris saponins and the potential development of XA-2 as a new therapeutic agent.
... In addition to hemostatic, analgesic, sedative, antibacterial, spermicidal, and immunomodulatory activities, polyphyllin also has antitumor effect [4][5][6]. Currently, scholars from various countries have reported a number of antitumor studies on this compound [7][8][9]. ...
... Bi and Ti were not detected in all samples. e planting years affected the content of inorganic elements in the rhizome of PPC. e variation curves of inorganic elements in samples with different planting years are shown in Figure 1. e changing trends in the content of Al (Figure 1 Isotopes measured 6 Li * , 7 Li, 9 Be, 11 B, 23 Na, 24 Mg, 27 Al, 31 Step T (°C) Pressure (atm) Power (W) Holding time (min) 1 120 40 1600 10 2 150 40 1600 20 3 180 40 1600 Among samples of all planting years, the elements Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, and Ni in Year 1 samples were the highest. e contents of majority inorganic elements were lower in Years 2-6 samples than in Year 1 samples. ...
The objective of this study was to investigate the concentrations of inorganic elements in the rhizome of Paris polyphylla Smith var. chinensis (Franch.) Hara of different planting years and cultivation conditions. Twenty-five inorganic elements including Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, Se, Sr, Ti, V, and Zn in the rhizome were determined by using inductively coupled plasma mass spectrometry (ICP-MS). The analytical method was validated by measuring several parameters including linearity, correlation coefficient, limit of detection (LOD), limit of quantification (LOQ), and recovery. The linear working ranges were three, 0-300 μg/L, 0-500 μg/L, and 0-1000 μg/L, and the correlation coefficients (r) values were higher than 0.998. LOD varied from 0.001 μg/L (Be) to 11.957 μg/L (P), and LOQ varied from 0.003 μg/L (Be) to 35.870 μg/L (P). The recoveries spanned from 95.2 (Co) to 105.3% (Pb). Validation parameters showed the possibility of using whole of the sample preparation procedures used in this study. Based on the determined results, it is indicated that the toxic elements As, Cd, and Pb had no ingestion risk. The planting years and cultivation conditions had significant effects on the concentrations of inorganic elements of P. polyphylla var. chinensis. The concentrations of inorganic elements in cultivated samples were different from those in wild samples. The results can provide useful theoretical basis for the quality control and rational use of P. polyphylla var. chinensis.
... BOS-93 induces A549 apoptosis. Apoptosis is a major form of cell death induced by chemotherapeutic agents (17). In the present study, A549 cells were treated with BOS-93 for 48 h. ...
... Given that both apoptosis and autophagy could be induced by BOS-93 in A549 cells, their mutual association was investigated. Several studies have reported that chemotherapeutic drugs can induce both apoptosis and autophagy in cancer cells (10,17). Autophagosome formation is regulated by the mTOR pathway, a major nutrient sensor (9). ...
The novel bromophenol derivative, 3-(3-bromo-5-methoxy-4-(3-(piperidin-1-yl)propoxy)benzylidene)-N-(4-bromophenyl)-2-oxoindoline-5-sulfonamide (BOS-93), was synthesized in the CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences (Qingdao, China). Experimental studies have demonstrated that it could induce apoptosis and autophagy in human A549 lung cancer cells, and it could also inhibit tumor growth in human A549 lung cancer xenograft models. In the present study, the molecular pathways underlying these effects were identified. The results demonstrated that BOS-93 could inhibit cell proliferation in A549 cells and block A549 cells at the G0/G1 phase. Furthermore, BOS-93 could induce apoptosis, activate caspase-3 and poly ADP ribose polymerase, and increase the B cell lymphoma (Bcl)-2 associated X protein/Bcl-2 ratio. Notably, BOS-93 could also induce autophagy in A549 cells. BOS-93-induced autophagy was confirmed by detecting light chain 3 (LC3)-I/LC3-II conversion and increasing expression of beclin1 and autophagy-related gene 14. Notably, BOS-93-induced autophagy could be inhibited by the autophagy inhibitor 3-MA. Flow cytometry, transmission electron microscopy (TEM) and western blot analysis indicated that BOS-93 induced apoptosis and autophagy activities by deactivating phosphoinositide 3-kinase/protein kinase B/mechanistic target of rapamycin and activating the mitogen-activated protein kinase signaling pathway. The present findings indicated that BOS-93 might be a novel anti-cancer agent for treatment of human lung cancer.
... Autophagy is a highly in conserved in intracellular degradative process. It plays contextual functions in the cancer cells, as it kills cancer cells but also protects cancer cells against injury 40,41 . A hallmark of autophagy is the formation of characteristic AVOs in autophagy sequester through cytoplasmic proteins. ...
... Thus, our results demonstrated that EP induced apoptosis and autophagy in A549 cells. These results were in parallel with previous reports that increased autophagy promotes apoptosis in various types of cancer cell lines 41,42 , in contrast to reduced autophagy increased apoptosis 43,44 . Several signaling pathways were reported to involve in the autophagy induction. ...
Abstract As part of our ongoing search for novel therapeutic structures from microorganism, the chemical examination of marine fungus Phoma sp. resulted in the isolation of ergosterol, ergosterol peroxide (EP), and 9,11-dehydroergosterol peroxide (DEP). The bioassay results demonstrated that the three isolates reduced the viability of various cancer cells, with EP being highest in human lung cancer cell line A549 cells. EP induced caspase-dependent apoptosis through mitochondrial damage in A549 cells. Additionally, EP-induced ROS generation and apoptosis were attenuated by ROS-generating enzymes inhibitors and antioxidant N-acetylcysteine, indicated that ROS played an important role in EP-mediated apoptosis in A549 cells. Furthermore, it was observed that EP induced ROS-dependent autophagy, which attenuated apoptosis in A549 cells. On the other hand, EP reduced the LPS/ATP-induced proliferation and migration of A549 cells through attenuated NLRP3 inflammasome activity. Additionally, EP showed synergistic cytotoxic effect with antitumor drug Sorafenib in A549 cell viability inhibition. Furthermore, Micro-Western Array and Western blot analyses demonstrated that the protein levels of EGFR, HSP27, MEK5, AKT1, mTOR, Smad2, Smad3, TAB1, NF-κB, and HIF1-α decreased, while the levels of p-p38α, p-ERK1/2, p-JNK, fibronectin and p27 increased. Collectively, the results of this study demonstrated that EP might be useful to develop a therapeutic candidate for lung cancer complications.
... Western blot analysis indicated that LC3BI and LC3BII, and Beclin 1, involved in autophagy formation, were found to be highly induced by ACT culture in a dose-dependent manner, while p62 was greatly reduced ( Figure 3D). According to previous studies, autophagy could protect the cell survival and induce cell death through various pathways [44]. In order to calculate if ACT-induced autophagy is a pro-death way or a pro-survival way, 3-MA, as essential autophagy inhibitor, was applied to pre-incubate the bladder cancer cells, followed by ACT treatment. ...
... LC3 is necessary during proteolytic processing, yielding a 16-kDa LC3-I protein that conjugates with phosphatidyl ethanolamine to yield a 14-kDa LC3-II form, in which LC3-II is used as a marker of complete activation of autophagosome [43,59,60]. The p62 protein is involved in the lysosomedependent degradation system that directly interacts with LC3-II and degradation in the process of autophagy, and suppression of autophagy results in enhanced p62 protein levels [44,61]. Accumulating evidence suggested the dual effect of autophagy on cancer, contributing to cell death or protecting cell survival [31,[33][34][35]. ...
Human bladder cancer is a common genitourinary malignant cancer worldwide. However, new therapeutic strategies are required to overcome its stagnated survival rate. Triterpene glycoside Actein (ACT), extracted from the herb black cohosh, suppresses the growth of human breast cancer cells. Our study attempted to explore the role of ACT in human bladder cancer cell growth and to reveal the underlying molecular mechanisms. We found that ACT significantly impeded the bladder cancer cell proliferation via induction of G2/M cycle arrest. Additionally, ACT administration triggered autophagy and apoptosis in bladder cancer cells, proved by the autophagosome formation, LC3B-II accumulation, improved cleavage of Caspases/poly (ADP-ribose) polymerase (PARP). Furthermore, reduction of reactive oxygen species (ROS) and p-c-Jun N-terminal kinase (JNK) could markedly reverse ACT-induced autophagy and apoptosis. In contrast, AKT and mammalian target of rapamycin (mTOR) were greatly de-phosphorylated by ACT, while suppressing AKT and mTOR activity could enhance the effects of ACT on apoptosis and autophagy induction. In vivo, ACT reduced the tumor growth with little toxicity. Taken together, our findings indicated that ACT suppressed cell proliferation, induced autophagy and apoptosis through promoting ROS/JNK activation, and blunting AKT pathway in human bladder cancer, which indicated that ACT might be an effective candidate against human bladder cancer in future.
... A previous study demonstrated that significant autophagy flux in FP-treated chronic lymphocytic leukemia (CLL) cells was initiated by FP-induced endoplasmic reticulum stress other than the result of directly inhibition of CDKs. Furthermore, inhibition of autophagy enhances FP cytotoxicity, which indicated that FP-induced autophagy may serve a drug resistance role in CLL cells (18). Autophagy and apoptosis were demonstrated to be induced by antitumor drugs in human breast cancer cell lines, such as Paris saponin XA-2 and rapamycin (19). ...
... Western blotting. MCF-7 cells were treated with rapamycin (5 µM) or FP (1 µM) with or without chloroquine (CQ; 500 nM; Sigma-Aldrich; Merck KGaA) for a total of 48 h at 37˚C, based on a previously published protocol (18). A total of 1 x10 6 MCF-7 cells were harvested by scraping the cells from culture plates and collected by centrifugation at 40 x g for 6 min at 4˚C. ...
Flavopiridol (FP) exerts antitumoral effects by triggering tumor cell cycle arrest and cytotoxicity in human breast cancer cell lines. The potent antitumor activity of FP is through its inhibition of cyclin‑dependent kinases; however, this may not be the only mechanism of action. The present study aimed to investigate whether FP is able to induce autophagy and to examine the effects of autophagy on cell death in FP‑treated MCF‑7 human breast cancer cells. MCF‑7 cells were treated with either FP alone or FP in combination with chloroquine (CQ). Expression levels of autophagy‑related protein LC3B‑II and p62/sequestosome 1 (SQSTM1) were used to monitor autophagic flux. MCF‑7 cells were transfected with autophagy‑related 5 (ATG5) small interfering (si)RNA to block autophagy. Cell viability and cell cycle status were determined. Following incubation with FP, MCF‑7 cells exhibited significantly higher autophagy compared with untreated control cells, and the level of autophagy is comparable with cells under rapamycin induction, which was verified by immunodetection of LC3B‑II and p62/SQSTM1 expression and inhibition by CQ. The addition of CQ treatment or ATG5‑siRNA transfection against autophagy components attenuated the cytotoxic effects of FP treatment of MCF‑7 cells. Furthermore, this autophagy inhibition did not impair the FP‑induced cell cycle arrest. These results revealed that autophagy may be involved in FP‑induced MCF‑7 cell death and autophagy inhibition enhanced the tumor cell pro‑survival ability. It is possibly that potential autophagy regulatory drugs may be used as a chemotherapy adjuvant.
... Tis saponin also arrests the cell cycle in the G1 phase. Moreover, autophagy, which can promote apoptosis in MCF-7 and MDA-MB-231 cell lines, was facilitated by XA-2 and inhibited the Akt/mTOR signaling pathway [57]. Because Paris saponins inhibits the activity of IKKβ and p65 translocation, they are recognized as NF-kB activation suppressors. ...
Paris polyphylla Smith (family: Melanthiaceae), a high-value medicinal herb endemic to the Himalayan region, has drawn much attention recently due to its immense use in the traditional healthcare system since ancient times. In the present review, an extensive database on P. polyphylla was systematically searched from databases such as Medline/PubMed, Scopus, the Web of Science, and the online service E-library.ru and SCImago (https://www.scimagojr.com/). Information on species, ecology, distribution, trade, ethnopharmacology, pharmacology, biotechnology, and molecular biology was gathered from 1979 to 2023 using 116 research publications. Major steroidal saponins such as Paris saponin I, V, VI, VII, and H have been found substantially efective in anticancer activity, abnormal uterine bleeding, dysfunctional uterine bleeding, and menorrhagia. Traditional breeding and propagation techniques cannot keep up with the world's growing demand for herbal drugs. Terefore, it is critically necessary to take conservation measures and develop novel techniques for growing and cultivating this economically signifcant and highly valuable therapeutic herb. Te advanced biotechnological approaches like micropropagation and genetic analysis introduced long back are either rare or lacking in the case of P. polyphylla. It contains a wealth of information that will serve as a baseline data source for various stakeholders, researchers working on various research aspects, and policymakers to defne appropriate utilization and conservation plans for a high-value commercial medicinal plant called P. polyphylla. Te review provides an updated overview and critical assessment of secondary data regarding the past and recent applications and interventions of P. polyphylla.
... Akt is an important signaling target downstream of PI3K and is divided into three main classes, namely, Akt1, Akt2, and Akt3 (Yu et al., 2018). PI3K-Akt and AKT/mTOR signaling pathways have key roles in cell survival (Tewari et al., 2022;Xie et al., 2017). mTOR is a serine/threonine kinase, a key protein essential for life processes. ...
Cancer poses a serious threat to human health, and the search for safe and effective drugs for its treatment has aroused interest and become a long-term goal. Traditional Chinese herbal medicine (TCM), an ancient science with unique anti-cancer advantages, has achieved outstanding results in long-term clinical practice. Accumulating evidence shows that saponins are key bioactive components in TCM and have great research and development applications for their significant role in the treatment of cancer. Saponins are a class of glycosides comprising nonpolar triterpenes or sterols attached to hydrophilic oligosaccharide groups that exert antitumor effects by targeting the NF-κB, PI3Ks-Akt-mTOR, MAPK, Wnt-β-catenin, JAK-STAT3, APMK, p53, and EGFR signaling pathways. Presently, few advances have been made in physiological and pathological studies on the effect of saponins on signal transduction pathways involved in cancer treatment. This paper reviews the phytochemistry and extraction methods of saponins of TCM and their effects on signal transduction pathways in cancer. It aims to provide theoretical support for in-depth studies on the anticancer effects of saponins.
... A study showed that the expression of SNAI2, Twist1, MMP-2, and MMP-9 in bladder cancer cells was significantly decreased, and cell scratch experiments showed significant inhibition of the migration and invasion of bladder cancer cells after polyphyllin II treatment (Niu et al., 2020). Polyphyllin II also induces autophagy through the Akt/mTOR signaling pathway, thereby promoting apoptosis of breast cancer cells (Xie et al., 2017). In addition, polyphyllin II treatment enhances the sensitivity of lung cancer cells to cisplatin, which provides important data support for polyphyllin II as a chemosensitizer (Man et al., 2020). ...
Cancer is a major threat to human health, with high mortality and a low cure rate, continuously challenging public health worldwide. Extensive clinical application of traditional Chinese medicine (TCM) for patients with poor outcomes of radiotherapy and chemotherapy provides a new direction in anticancer therapy. Anticancer mechanisms of the active ingredients in TCM have also been extensively studied in the medical field. As a type of TCM against cancer, Rhizoma Paridis (Chinese name: Chonglou) has important antitumor effects in clinical application. The main active ingredients of Rhizoma Paridis (e.g., total saponins, polyphyllin I, polyphyllin II, polyphyllin VI, and polyphyllin VII) have shown strong antitumor activities in various cancers, such as breast cancer, lung cancer, colorectal cancer, hepatocellular carcinoma (HCC), and gastric cancer. Rhizoma Paridis also has low concentrations of certain other active ingredients with antitumor effects, such as saponins polyphyllin E, polyphyllin H, Paris polyphylla-22, gracillin, and formosanin-C. Many researchers have studied the anticancer mechanism of Rhizoma Paridis and its active ingredients. This review article describes research progress regarding the molecular mechanism and antitumor effects of the active ingredients in Rhizoma Paridis, suggesting that various active ingredients in Rhizoma Paridis may be potentially therapeutic against cancer.
... As such, strategies of activating lysosomes via cathepsins, autophagy related genes as well as STAT3, could be considered as promising ways to treat breast cancers [141,142]. Paradoxically, autophagy prolongs dormant breast cancer cell survival through clearing away damaged mitochondria which would normally induce apoptosis [143]. With exception to the association of autophagy and breast cancer progression, ferroptosisinduced inhibition of breast tumor malignancy also requires the disruption of lysosome. ...
The mammary gland undergoes a spectacular series of changes during its development and maintains a remarkable capacity to remodel and regenerate during progression through the lactation cycle. This flexibility of the mammary gland requires coordination of multiple processes including cell proliferation, differentiation, regeneration, stress response, immune activity, and metabolic changes under the control of diverse cellular and hormonal signaling pathways. The lactating mammary epithelium orchestrates synthesis and apical secretion of macromolecules including milk lipids, milk proteins, and lactose as well as other minor nutrients that constitute milk. Knowledge about the subcellular compartmentalization of these metabolic and signaling events, as they relate to milk production and secretion during lactation, is expanding. Here we review how major organelles (endoplasmic reticulum, Golgi apparatus, mitochondrion, lysosome, and exosome) within mammary epithelial cells collaborate to initiate, mediate, and maintain lactation, and how study of these organelles provides insight into options to maintain mammary/breast health.
... In particular, the antitumor pharmacological activity of Rhizoma Paridis extracts has emerged a major focus of research. Recent several years, polyphylla saponins have been widely reported to inhibit tumor growth in cancer of the breast [13], liver [14], lung [15], ovary [16], and colon [17], as well as other types of malignancy. All these findings bring lights to the discovery of new drugs for cancer. ...
Rhizoma Paridis, the rhizome of liliaceous plants Paris polyphylla, is one of the most commonly used herbal drugs in China. Phytochemical and pharmacological studies have shown that steroid saponins were the major effective ingredients of Rhizoma Paridis to exert antitumor, anti-inflammatory, hemostasis, and antifibrosis functions. In this review, we discussed the chemical structures of steroid saponins and their related biological activity and mechanisms in cellular and animal models, aiming to provide a reference for future comprehensive exploitation and development of saponins.
... It could be beneficial for treating ovarian cancer and used in cancer therapy (Wang et al., 2016). Xie et al. (2017) isolated saponin compound, XA-2 and confirmed induced apoptosis in breast cancer cell lines (MCF-7 and MDA-MB-231). The Akt/mTOR signaling pathway proteins-Akt, mTOR, P70S6K, and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1) were found to be decreased indicating the potentiality of XA-2 as an anticancer drug. ...
... It reduces the level of various factors involved in mTOR/Akt signaling pathway and also phosphorylated forms of mTOR, Akt, and P70S6K. It upregulates the proapoptotic Bax expression, downregulates the antiapoptotic Bcl-2 expression, and activates the caspase-9 (Xie et al., 2017). ...
Breast cancer (BC), the leading cause of female mortality worldwide, is caused by multiple signaling pathways. This chapter discusses major pathways underlying the cancer pathogenesis, namely, Notch pathway, Wnt/β-catenin pathway, Hedgehog pathway, NF-κB pathway, receptor tyrosine kinase pathway, Ras/MEK/Raf/ERK signaling pathway, AKT/phosphoinositide 3 kinase (PI3K) pathway, PI3Ks Class I, PI3Ks Class II and III, c-JUN NH2-terminal kinase pathway, heat shock protein 90 signaling pathway, poly(ADP-ribose) polymerase 1 signaling pathway, angiogenesis pathway, estrogen receptor signaling pathway, mammalian target of rapamycin pathway, and protein kinase C pathway. All these pathways are misregulated in BC conditions and their misregulation can be controlled by pharmacological inhibitors. Since chemical drugs or inhibitors may have some side effects and cancer cells may develop drug resistivity, a need for the study of medicinal plants, their extracts, and polyherbal formulae is warranted. Thus, this chapter is planned to focus on the various plants and their extracts that show remarkable anticancer activity. Further, it discusses about the role of pure phytochemicals like flavonoids, semisynthetic flavonoids and phenols, and polyphenols in controlling BC. This chapter will help to establish medicinal plant therapy as an effective alternative to improve the existing chemotherapy and to reduce drug-induced toxicity.
... However, the PI3/Akt/mTOR signaling pathway, which mediates crosstalk between autophagy and apoptosis, appears to be the most studied [93,96]. Xie et al. reported the induction of autophagy by Paris saponins from Paris polyphyllae through the downregulation of Akt/mTOR in breast cancer cells [97]. Triterpenoid glycosides are also reported to induce apoptosis in hepatocellular carcinoma by modulating the PI3K/Akt/mTOR signaling pathway [98]. ...
Saponins are steroidal or triterpenoid glycoside that is distinguished by the soap-forming nature. Different saponins have been characterized and purified and are gaining attention in cancer chemotherapy. Saponins possess high structural diversity, which is linked to the anticancer activities. Several studies have reported the role of saponins in cancer and the mechanism of actions, including cell-cycle arrest, antioxidant activity, cellular invasion inhibition, induction of apoptosis and autophagy. Despite the extensive research and significant anticancer effects of saponins, there are currently no known FDA-approved saponin-based anticancer drugs. This can be attributed to a number of limitations, including toxicities and drug-likeness properties. Recent studies have explored options such as combination therapy and drug delivery systems to ensure increased efficacy and decreased toxicity in saponin. This review discusses the current knowledge on different sapo-nins, their anticancer activity and mechanisms of action, as well as promising research within the last two decades and recommendations for future studies.
... reported the induction of autophagy by Paris saponins from Paris polyphyllae through the downregulation of Akt/mTOR in breast cancer cells [98]. Triterpenoid glycosides are also reported to induce apoptosis in hepatocellular carcinoma by modulating PI3K/Akt/mTOR signalling pathway [99]. ...
Traditional plants are known to contain a wide array of secondary metabolites with important
biological activity, including anticancer activity. One of such metabolites is saponin; a steroidal or triterpenoid glycoside that is distinguished by its soap forming nature. Different saponins have been characterized and purified so far, and are gaining attention in cancer chemotherapy. Saponins possess incredible structural diversity which has been linked to their activity. They have been implicated in cancer chemoprevention and chemotherapy. Several studies have reported the role of saponins in cancer and their mechanism of actions including cell cycle arrest, antioxidant, cellular invasion inhibition, induction of apoptosis and autophagy. Despite the extensive research and significant anticancer effect of saponins there are no known FDA approved saponin based anticancer drugs due to a number of limitations including toxicities and drug likeness properties. Recent studies have explored options such as structural optimization, combination therapy and drug
delivery systems to design saponins with increased efficacy and decreased toxicities. This review discussed the current knowledge on different saponins, their anticancer activity, mechanism of action as well as the current promising research on saponins within the last two decades and recommendations for future studies.
... Apoptosis is a process of genetically programmed cell death, which plays a vital role in the development of tumor cells. 43 47) reported that ARG induced apoptosis and autophagy of glioma cells in a dose-dependent manner, and confirmed that ARG induced apoptosis and autophagy through Akt/mTOR signaling pathway by detecting apoptotic-and autophagy-related proteins. Wang et al. 48) showed that ARG could enhance the sensitivity of colorectal cancer cells by activating autophagy, thereby induced apoptosis and inhibited cell growth. ...
Arctigenin(ARG) , a natural lignans compound isolated from Arctium lappa L. In this study, the anti-tumor effect of ARG on prostate cancer cell PC-3M and the mechanism of apoptosis and autophagy induced by PI3K/Akt/mTOR signaling pathway were discussed, and further confirmed by the joint treatment of ARG and PI3K inhibitor LY294002. Here, the effect of ARG on cell viability was evaluated in PC-3M cells by CCK-8 assay. After the treatment of ARG, colony formation assay was used to detect the anti-proliferation effect. Annexin V-FITC/PI kit and DAPI staining were used to detect the apoptosis level, and cell cycle changes were analyzed by flow cytometry. The expression of autophagy was detected by acridine orange staining. In addition, the expression levels of apoptosis and autophagy-related proteins were analyzed by western blot. The result showed that different concentrations of ARG inhibited the proliferation of PC-3M cells. DAPI staining and flow cytometry showed that ARG induced PC-3M cell apoptosis and arrested cell in G0/G1 phase. Acridine orange staining showed that ARG induced autophagy in PC-3M cells. Western blot experiments showed that ARG inhibited the expression of Bcl-2 , promoted the expression of Bax and cleaved caspase-3. At the same time, the expression of autophagy-related proteins LC3B-II and Beclin-1 increased after ARG treatment, but P62 decreased. In addition, further studies have shown that treatment with LY294002 enhanced the effects of ARG on the expression of proteins associated with apoptosis and autophagy , indicating that ARG may induce apoptosis and autophagy through PI3K/Akt/mTOR pathway.
... In recent years, substantial evidence has shown that the ethanol (EtOH), water (H 2 O), and methanol (MeOH) extracts of P. polyphylla possess marked growth-inhibitory effect on tumors, including breast cancer, bladder cancer, prostate cancer, lung cancer, and ovarian cancer. Xie et al. (2017) found that saponins isolated from P. polyphylla exhibited anti-tumor activity against breast cancer cell lines (MCF-7 and MDA-MB-231) and found that paris saponin-induced autophagy promotes breast cancer cell apoptosis via the Akt/mTOR signaling pathway. Sun et al. (2007) showed that the ethanol extract had a more powerful inhibitory effect than the aqueous extract on human cell lines, including human liver carcinoma cell lines (HepG-2 and SMMC-7721), human gastric cancer cell line (BGC-823), human colon adenocarcinoma cell lines (LoVo and SW-116), and esophagus adenocarcinoma cell line (CaEs-17). ...
Paris species are traditionally used as medicinal herbs in China, India, Nepal, and other neighboring countries as well (Cunningham et al. 2018). Paris species are well known in China, where nearly all species having a thick rhizome are used to treat various diseases; for example, the dried rhizomes of Paris chinensis and P. yunnanensis bear the pharmaceutical name “Rhizoma Paridis” (China Pharmacopoeia Commission 2015). The earliest literature on Paris species utilized as herbal medicine dates back to 2000 years ago, during the Chinese Dong-Han Dynasty (25–220 AD) (Li et al. 2015). Rhizoma Paridis (Fig. 4.1) was originally used to treat snake bites and swelling. In the last 50 years, its hemostasis, anti-inflammatory, analgesic, cough suppressant, antipyretic, anti-tumor, immuno-stimulating, anthelmintic, antimicrobial, and protective effects on ethanol- or indomethacin-induced gastric mucosal lesions, and other therapeutic properties became known and were described.
... In some cases, autophagy promotes cell apoptosis. Paris saponin-induced autophagy promotes ALL cell apoptosis through the Akt/mTOR signaling pathway [25]. Parthenolide inhibits pancreatic cell progression by autophagy-mediated apoptosis [26]. ...
Background: Acute lymphoblastic leukemia (ALL) is an aggressive hematopoietic malignancy that is most commonly observed in children. Alantolactone (ALT) has been reported to exhibit anti-tumor activity in different types of cancer. The aim of the present study was to investigate the anti-tumor activity and molecular mechanism of ALT in ALL.
Methods: ALL cell lines were treated with 1, 5 and 10 μM ALT, and cell viability was assessed using an MTT assay and RNA sequencing. Flow cytometry, JC-1 staining and immunofluorescence staining assays were used to measure cell apoptosis and autophagy. Additionally, western blot analysis was used to detect expression of apoptosis and autophagy related proteins. Finally, the effects of ALT on tumor growth were assessed in a BV173 xenograft nude mouse model.
Results: ALT inhibited the proliferation of ALL cells in a dose-dependent manner. Additionally, it was demonstrated that ALT inhibited cell proliferation, colony formation, autophagy, induced apoptosis and reduced tumor growth in vivo through upregulating the expression of adaptor related protein complex 2 subunit mu 1 (AP2M1). Moreover, the autophagy activator rapamycin, attenuated the pro-apoptotic effects of ALT on BV173 and NALM6 cell lines. Overexpression of AP2M1 decreased the expression of Beclin1 and the LC3-II/LC3-1 ratio, and increased p62 expression. Knockdown of Beclin1 increased the levels of bax, cleaved caspase 3 and cytochrome C, and decreased bcl-2 expression.
Conclusions: The present study demonstrated that ALT exerts anti-tumor activity through inducing apoptosis and inhibiting autophagy by upregulating AP2M1 in ALL, highlighting a potential therapeutic strategy for treatment of ALL.
... In some cases, autophagy promotes cell apoptosis. Paris saponin-induced autophagy promotes ALL cell apoptosis through the Akt/mTOR signaling pathway [25]. Parthenolide inhibits pancreatic cell progression by autophagy-mediated apoptosis [26]. ...
Background:
Acute lymphoblastic leukemia (ALL) is an aggressive hematopoietic malignancy that is most commonly observed in children. Alantolactone (ALT) has been reported to exhibit anti-tumor activity in different types of cancer. The aim of the present study was to investigate the anti-tumor activity and molecular mechanism of ALT in ALL.
Methods:
ALL cell lines were treated with 1, 5 and 10 μM ALT, and cell viability was assessed using an MTT assay and RNA sequencing. Flow cytometry, JC-1 staining and immunofluorescence staining assays were used to measure cell apoptosis and autophagy. Additionally, western blot analysis was used to detect expression of apoptosis and autophagy related proteins. Finally, the effects of ALT on tumor growth were assessed in a BV173 xenograft nude mouse model.
Results:
ALT inhibited the proliferation of ALL cells in a dose-dependent manner. Additionally, it was demonstrated that ALT inhibited cell proliferation, colony formation, autophagy, induced apoptosis and reduced tumor growth in vivo through upregulating the expression of adaptor related protein complex 2 subunit mu 1 (AP2M1). Moreover, the autophagy activator rapamycin, attenuated the pro-apoptotic effects of ALT on BV173 and NALM6 cell lines. Overexpression of AP2M1 decreased the expression of Beclin1 and the LC3-II/LC3-1 ratio, and increased p62 expression. Knockdown of Beclin1 increased the levels of bax, cleaved caspase 3 and cytochrome C, and decreased bcl-2 expression.
Conclusions:
The present study demonstrated that ALT exerts anti-tumor activity through inducing apoptosis and inhibiting autophagy by upregulating AP2M1 in ALL, highlighting a potential therapeutic strategy for treatment of ALL.
... Tubeimoside-1 inhibits human cancer cells via Akt-mediated pathway (Jiang et al. 2019). Paris saponin is more effective against breast cancer cell by triggering apoptosis via AKT/mTOR signaling pathway (Xie et al. 2017). Paris saponin VII reported from the roots and rhizomes of Trillium tschonoskii, which induces apoptosis by regulating Akt/MAPK pathway . ...
Saponins are a class of amphipathic glycosides prevalent in various plant species. They are very important for human health and may be used in various drug formulations. Saponins play vital roles in inhibition of many singling pathways such as PI3K/AKT pathway, AKT/MAPK pathway, EGFR/PI3K/AKT pathway, PI3K/AKT/mTOR pathway, and RNF6/AKT/mTOR pathway. They have been reported to exhibit cytotoxic activities on HepG2, NCI-H460, MCF-7, HT1080, A549, Hela, LN229, H1299, SGC7901, and MDA-MB-231 cancer cell lines. Several types of bioactive saponins such as Dammarane, Cycloartane, Hopane, Lupane, Oleanane, Ursane, Steroids, Spirostanol, and Furastanol have been reported from various plant species. The present review mainly focuses on the sources of medicinal-plant-based saponins with biological activities. This review covers ~101 references from 2015 to 2019.
... Tubeimoside-1 inhibits human cancer cells via Akt-mediated pathway (Jiang et al. 2019). Paris saponin is more effective against breast cancer cell by triggering apoptosis via AKT/mTOR signaling pathway (Xie et al. 2017). Paris saponin VII reported from the roots and rhizomes of Trillium tschonoskii, which induces apoptosis by regulating Akt/MAPK pathway . ...
Dieffenbachia amoena is a house plant and known dumb
cane. The study was performed based on isolation and structure
elucidation of phytosterols from the extract of this plant. The CH3OH
crude extract was loaded over the silica gel (60-120 mesh) column, using
the stepwise gradient C6H6, CH3OAc, CH3OH. The fractions were further
purified by preparative TLC (GF254) to yield compound (1). Compound
(1) was characterized by using various standard spectroscopic techniques
such as IR, 1HNMR, 13CNMR, DEPT-135, COSY, HSQC and HMBC.
Based on the spectral analysis, it was confirmed that the compound (1)
was a mixture of β-sitosterol and stigmasterol. Phytosterols have high
medicinal importance and play a vital role in reducing blood cholesterol,
a high level of blood cholesterol can cause a risk of cardiovascular
disease. Cardiovascular disease is the main problem of the whole world
and increasing day by day. We have isolated β-sitosterol and stigmasterol
first time from the leaves of the Dieffenbachia amoena plant.
... In some cases, autophagy promotes cell apoptosis. Paris saponininduced autophagy promotes acute lymphoblastic leukemia cell apoptosis through the Akt/mTOR signaling pathway [25]. Parthenolide inhibits pancreatic cell progression by autophagy-mediated apoptosis [26]. ...
Background: Acute lymphoblastic leukemia (ALL) is an aggressive hematopoietic malignancy that is most common in children. Alantolactone (ALT) has been reported to have antitumor activity in different types of cancers. This study aimed to investigate the antitumor activity and molecular mechanism of ALT in ALL.
Methods: The ALL cell lines were treated with 1, 5 and 10μM of ALT, and then subjected to MTT assay and RNA sequencing. Flow cytometry, JC-1 staining and immunofluorescence staining assays were employed to measure cell apoptosis and autophagy. Meanwhile, Western blot analysis was used to detect apoptosis and autophagy related proteins. Finally, the effect of ALT on tumor growth was measured in BV173 xenograft nude mouse model.
Results: In this study, we demonstrated that ALT inhibited the proliferation of ALL cells in does-dependent manner. A series of experiments demonstrated that ALT inhibited cell proliferation, colony formation, autophagy, induced apoptosis and restained tumor growth in vivo through upregulating adaptor related protein complex 2 subunit mu 1 (AP2M1). Moreover, autophagy activator rapamycin attenuated the pro-apoptotic effect of ALT on BV173 and NALM6 cell lines. Further, overexpressed AP2M1 decreased the expression of Beclin1, LC3-II/LC3-1 ratio and increased p62 expression. Fianally, knockdown of Beclin1 increased the levels of bax, cleaved caspase 3 and cytochrome C and decreased bcl-2 expression.
Conclusions: This study demonstrated that ALT exerts antitumor activity through inducing apoptosis and inhibiting autophagy by upregulating AP2M1 in ALL, indicating a potential therapeutic strategy for ALL treatment.
... Some anticancer agents can induce autophagy by blocking the PI3K/AKT pathway. In addition, the mTOR inhibitor rapamycin induces the occurrence of autophagy as a mechanism to promote tumor survival [49,50]. Drugs developed recently as Akt/mTOR dual inhibitors are currently being tested in clinical trials [51,52]. ...
PDB-1 is a new C-27-carboxylated-lupane-triterpenoid derivative isolated from Potentilla discolor Bunge. In our previous research, PDB-1 was suggested to have an obvious selectivity for tumor cells. This study focused on clarifying PDB-1’s anticancer mechanism in the inhibition of proliferation and in the induction of apoptosis and autophagy in A549 cells. In general, A549 cells were treated with PDB-1 for different times, and cell survival was assessed by a CCK8 assay. The assessment of intracellular reactive oxygen species, a mitochondrial membrane potential assay, a cell cycle assay, an annexin V-FITC/PI assay, and MDC staining were performed in A549 cells treated with PDB-1. Moreover, the mRNA and protein expression of cell cycle-, apoptosis- and autophagy-related factors were detected by RT-qPCR and western blotting. The results showed that PDB-1 inhibited A549 cell proliferation and colony formation in a dose- and time-dependent manner. The decrease in the viability of A549 cells was due to a G2/M cell cycle arrest. Moreover, PDB-1 induced cell apoptosis, accompanied by an increase in the Bax/Bcl-2 ratio and an increase in the expression levels of cleaved caspase-3/caspase-9. We also found that PDB-1 induced autophagy by increasing the conversion of LC3-I to LC3-II and elevating Beclin-1. In addition, further studies indicated that pretreatment with a specific PI3K inhibitor (LY294002) enhanced the effects of PDB-1 on the expression of proteins associated with apoptosis and autophagy, demonstrating that the PI3K/Akt/mTOR pathway was related to PDB-1-induced apoptosis and autophagy. These results indicated that PDB-1 may be considered a potential candidate for the future treatment of lung adenocarcinoma. These findings should benefit the development of the C14-COOH type of pentacyclic triterpenoids.
... In some cases, autophagy promotes cell apoptosis. Paris saponin-induced autophagy promotes acute lymphoblastic leukemia cell apoptosis through the Akt/mTOR signaling pathway [24]. Parthenolide inhibits pancreatic cell progression by autophagy-mediated apoptosis [25]. ...
Background: Acute lymphoblastic leukemia (ALL) is an aggressive hematopoietic malignancy and most commonly seen in children. Alantolactone (ATL) has been reported to have anti-tumor activities in different types of cancer. This study aimed to evaluate the anti-tumor activity and molecular mechanisms of ATL in ALL.
Methods: The ALL cells were treated with 1, 5 and 10μM of of ALT, and then subjected to MTT assay and RNA sequencing. Flow cytometry, JC-1 staining and immunofluorescence staining assay were employed to measure cell apoptosis and autophagy. Meanwhile, western blot analysis was used to detect apoptosis and autophagy-related proteins. Finally, the effect of ALT on tumor growth was measured in BV173 xenograft nude mouse model.
Results: In this study, we demonstrated that ALT could inhibit the proliferation of ALL cells by inducing apoptosis and inhibiting autophagy. Administration of rapamycin activated autophagy while reversing the effect of ALT on apoptosis. Mechanically, ALT could induce apoptosis and inhibit autophagy by promoting AM2P1 expression. Further, AM2P1 was figured to inhibit beclin1 phosphorylation so that the apartment between beclin1 and bcl-2 was alleviated to participate in the regulation of autophagy and apoptosis in ALL cell.
Conclusions: This study disclosed that Alantolactone can inhibit cell autophagy and promote apoptosis through targeting AP2M1 in acute lymphotic leukemia, indicating a potential therapeutic strategy for ALLtreatment.
... Apoptosis, a critical form of genetically encoded programmed cell death, is closely associated with tumor development and is often regarded as a useful strategy in anti-cancer management (Xie et al., 2017). Mitochondrial apoptotic pathway has been reported to be one of the major apoptotic pathways (Czabotar, Lessene, Strasser, & Adams, 2014). ...
The effect of 5-heptadecylresorcinol (AR-C17) on the proliferation of human MCF-7 breast cancer cells was investigated in the present study. The results showed that AR-C17 treatment significantly suppressed MCF-7 cells proliferation, trigged intracellular ROS generation and decreased SOD2 expression. Furthermore, AR-C17 treatment could lead to MCF-7 cells apoptosis as evidenced by the activation of Bax/Bcl-2 expression ratio, active caspase activity and downregulation of mitochondrial membrane potential. Meanwhile, AR-C17 could activate MCF-7 cells autophagy by upregulating the protein levels of Atg7, Beclin-1 and LC3-Ⅱ as well as decreasing SQSTM1/p62 and increasing autophagosomes formation in cytoplasm. Inhibition of autophagy with chloroquine (CQ) enhanced AR-C17-induced cell apoptosis. In addition, AR-C17 exerted anti-cancer activity through modulating PI3K/Akt/mTOR signaling pathway which was evidenced by decreasing the protein expression of PI3K, p-Akt and p-mTOR. Co-treatment with PI3K agonist IGF-1 could alleviate the inhibitory effect of AR-C17. Taken together, AR-C17 could be used as potential nutraceutical for breast cancer management.
... Studies have demonstrated that AKT and mTOR are inhibitors of autophagy, and overexpression of these genes inhibits tumor cells to undergo autophagic transformation [43][44][45]. Reduced levels of AKT/mTOR signaling pathway proteins such as phospho-AKT and mTOR are also shown in autophagy [46]. Autophagy plays a protective role for are showing in MED12-mut stable clone as compared with MED12-WT stable clone. ...
Uterine fibroids (UFs) or leiomyoma are frequently associated with somatic mutations in the mediator complex subunit 12 (MED12) gene; however, the function of these mutations in human UF biology is yet to be determined. Herein, we determined the functional role of the most common MED12 somatic mutation in the modulation of oncogenic Wnt4/β-catenin and mammalian target of rapamycin (mTOR) signaling pathways. Using an immortalized human uterine myometrial smooth muscle cell line (UtSM), we constitutively overexpressed either MED12-Wild Type or the most common MED12 somatic mutation (c.131G>A), and the effects of this MED12 mutation were compared between these cell lines. This immortalized cell line was used as a model because it expresses wild type MED12 protein and do not possess MED12 somatic mutations. By comparing the effect between MED12-WT and MED12-mutant (mut) stable cell populations, we observed increased levels of protein expression of Wnt4 and β-catenin in MED12-mut cells as compared with MED12-WT cells. MED12-mut cells also expressed increased levels of mTOR protein and oncogenic cyclin D1 which are hallmarks of cell growth and tumorigenicity. This somatic mutation in MED12 showed an effect on cell-cycle progression by induction of S-phase cells. MED12-mut cells also showed inhibition of autophagy as compared with MED12-WT cells. Together, these findings indicate that the MED12 somatic mutation has the potentials for myometrial cell transformation by dysregulating oncogenic Wnt4/β-catenin and its downstream mTOR signaling which might be associated with autophagy abrogation, cell proliferation, and tumorigenicity.
... Akt promotes cell survival and also abrogates the negative regulatory effect of the transcription factor NF-κB, resulting in an increase in transcription of anti-apoptotic and pro-survival genes [50]. mTOR is a highly conserved serine/threonine kinase, and its expression regulates metabolism and growth, and additionally integrates the signals from many stimuli [51]. Phosphorylation of these proteins is an important regulatory mechanism that results in conformational changes of many enzymes and receptors, resulting in their activation/ deactivation [52]. ...
Background:
The aim of the present study was to examine the effects of the Bolbostemma paniculatum (Maxim.) Franquet (BP) active compound, BP total saponins (BPTS), on MDA-MB-231 cells, and investigate the underlying mechanism regarding BPTS-mediated attenuation of the PI3K/Akt/mTOR pathway.
Methods:
The effect of BPTS on cytotoxicity, induction of apoptosis and migration on MDA-MB-231 cells at three different concentrations was investigated. A CCK-8 assay, wound-healing assay and flow cytometry were used to demonstrate the effects of BPTS. Additionally, expression of the primary members of the PI3K/Akt/mTOR signaling pathway was assessed using western blotting. To verify the underlying mechanisms, a PI3K inhibitor and an mTOR inhibitor were used.
Results:
BPTS inhibited proliferation of MDA-MB-231 cells with an IC50 value of 10 μg/mL at 48 h. BPTS inhibited migration of MDA-MB-231 cells, and the western blot results demonstrated that BPTS reduced p-PI3K, p-Akt and p-mTOR protein expression levels in MDA-MB-231 cells. Additionally, the results were confirmed using a PI3K inhibitor and an mTOR inhibitor. BPTS decreased proliferation and migration of MDA-MB-231 cells possibly through inhibiting the PI3K/Akt/mTOR signaling pathway.
Conclusions:
The results highlight the therapeutic potential of BPTS for treating patients with triple-negative breast cancer.
... Most previous studies have concentrated mainly on its geographical distribution and chemical compounds (Kang et al. 2017;Cunningham et al. 2018). Steroidal saponins obtained from its rhizomes displayed cytotoxic activity against various tumor cells (Zhang et al. 2015;Liu et al. 2016;Xie et al. 2017). In recent years, its natural population decreased drastically because of deforestation. ...
Paris polyphylla var. chinensis is a species of flowering herb of the family Liliaceae and widely distributed in 12 provinces in China. It has been used in Chinese traditional medicine for centuries. The chloroplast (cp) genome of P. polyphylla var. chinensis, sequenced based on next-generation platform (NEOSAT), is 164,429 bp in size. The cp genome encodes 133 genes, including eight rRNA genes, 87 protein-coding genes (PCGs), and 38 tRNA genes. Phylogenetic relationship analysis based on complete cp genome sequences exhibited that P. polyphylla var. chinensis was most related to Daiswa forrestii.
... Similar findings have recently studied that autophagy can also be induced by inhibition of the PI3K/Akt pathway (Chun et al., 2014;Xie et al., 2017). Expression and transcriptional activity of the androgen receptor might be supervised by crucial factors in PI3K/Akt/mTOR pathway (Manin et al., 2002;Yang et al., 2005). ...
... A few reports have demonstrated the complex interaction between autophagy and apoptosis [42][43][44][45]. Autophagy was observed to promote apoptosis via the Akt/mTOR signaling pathway in breast cancer cell lines during the combined treatment [46]. Moreover, miR-30a and miR-205 were reported to simultaneously suppress TP53INP1 expression to mediate apoptosis after irradiation [22]. ...
Purpose
To investigate the role of microRNAs in the regulation of autophagy and apoptosis in lens epithelial cells (LECs) during diabetic cataract formation.
Methods
A miRNA microarray study and quantitative real-time PCR were performed to identify the expression of miRNAs in LECs of diabetic cataract. Human LECs were cultured in high glucose conditions as a diabetic cataract model. BECN1 and LC3B were detected by Western blotting and quantitative real-time PCR. The extent of apoptosis was measured using FACSCalibur flow cytometry.
Results
Downregulation of miR-30a was identified in LECs attached to diabetic cataract tissues. By the bioinformatic assay and the luciferase activity assay, BECN1 was found to be a direct target of miR-30a. MiR-30a reduced the BECN1-mediated autophagy activity induced by high glucose in LECs in vitro. The ratio of LECs apoptosis was also decreased.
Conclusion
MiR-30a was involved in the inhibition of autophagy by targeting BECN1 in LECs in human diabetic cataract.
... We have observed both apoptosis and autophagy following the treatment of BME in breast cancer cells and preclinical models. Recent study reported that Paris saponins induce anticancer activity in breast cancer cells by inducing apoptosis and autophagy [28]. Akt/mTOR signaling pathway is involved in many cellular functions including apoptosis. ...
Breast cancer is a major public health problem worldwide in women and current therapeutic strategies are not adequately effective for this deadly disease. We have previously shown the anti-proliferative activity of bitter melon extract (BME) in breast cancer cells. In this study, we observed that BME treatment induces autophagosomebound Long chain 3 (LC3)-B and accumulates protein p62/SQSTM1 (p62) in breast cancer cells. Additionally, we observed that BME treatment in breast cancer cells increases phospho-AMPK expression and inhibits the mTOR/Akt signaling pathway. Subsequently, we demonstrated that BME feeding effectively inhibited breast cancer growth in syngeneic and xenograft mouse models. Further, we observed the increased p62 accumulation, induction of autophagy and apoptotic cell death in tumors from BME-fed animals. Taken together, our results demonstrate that BME treatment inhibits breast tumor growth, and this anti-tumor activity in breast cancer is, in part, mediated by induction of autophagy and modulation of the AMPK/mTOR pathway. The antitumor activity of BME by oral feeding in breast cancer models suggested the high potential for a clinical application.
Background
Polyphyllin is a class of saponins extracted from Paris polyphylla rhizomes and has been used in clinical application in China for more than 2000 years. However, the mechanism for treating gastric cancer (GC) is still unclear. This study was designed to predict the targets and mechanisms of total Polyphyllin from Paris polyphylla rhizomes for the treatment of GC.
Method
Firstly, PubChem and Swiss Target Prediction databases were utilized to collect the 12 ingredients of total Polyphyllin from Paris polyphylla rhizomes and their targets. GC-related genes were obtained from the GEO database. Then the intersecting targets to all these molecules that identified using Venny. Secondly, the intersecting targets were imported into STRING platform for protein-protein interaction (PPI) network. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted in DAVID website. In addition, the GEPIA was applied to perform the expression levels, transcript levels, staging, and overall survival of hub genes. In addition, we used AutoDock Vina to evaluate binding affinity of molecular docking between key ingredients and anti-GC targets. In vitro cell experiments, we detected the cell viability of gastric cancer cells at 24, 36, and 48 h using CCK-8 assay. The G0/G1 of cell cycle and apoptosis were detected by flow cytometry. Finally, quantitative real time polymerase chain reaction (qRT-PCR) was used to detect the level of hub genes, and Western blot was used to detect the changes of PI3K/Akt signal pathway.
Results
Firstly, we identified 12 ingredients and 286 targets of total Polyphyllin. A total of 2653 GC-related differentially expressed genes (DEGs) were collected, including 1366 up-regulated genes and 1287 down-regulated genes. Moreover, 45 targets were obtained after intersection. Secondly, results of the GO enrichment suggested that these genes were closely related to cell proliferation, migration and aging. KEGG analysis suggested that Polyphyllin in GC therapy were mostly regulated by multiple pathways, including the pathways in cancer, calcium signaling pathway, Rap1 signaling pathway, phospholipase D signaling pathway, etc. In addition, GEPIA results exhibited that PDGFRB, KIT, FGF1, GLI1, F2R, and HIF1A were associated with GC progression, stage, and survival. Besides, the molecular docking results further confirmed that the binding energy of Polyphyllin Ⅲ with HIF1A was minimal. In vitro cell experiments, Polyphyllin Ⅲ inhibited the cell viability of gastric cancer cells, blocked the cell cycle G0/G1 phase, and induced cell apoptosis. In addition, Polyphyllin Ⅲ down-regulated the mRNA levels of PDGFRB, KIT, FGF1, GLI1, F2R, and HIF1A, and regulated the PI3K/Akt signal pathway.
Conclusions
The results revealed that total Polyphyllin treated GC through multiple targets, multiple channels, and multiple pathways. In addition, Polyphyllin Ⅲ played an anti-gastric cancer role by inhibiting the proliferation of gastric cancer.
Phytochemicals refer to a large group of non-nutritious but bioactive compounds derived from plant foods including fruits, vegetables, and grains. Due to the considerable diversity in their chemical structures, phytochemicals can be divided into phenolic compounds, carotenoids, terpenoids, organosulfur compounds, glucosinolates, saponins, phytoestrogens, phytic acid, phytosterols, etc. Phytochemicals are not only important for plant growth, but also helpful for plants to survive under various environmental stresses and resist infections of viruses, bacteria, yeasts, and fungi. At the same time, the beneficial roles of phytochemicals in improving human health, such as protecting against coronary heart disease, diabetes, cancers, hypertension, inflammation, and other chronic diseases, have gained increasing interest in recent years. In this chapter, we summarized the definition, classification, physicochemical property, pharmacokinetics, biological effects, and health functions of phytochemicals.KeywordsPhytochemicalsPlant foodsBioactive compoundsHealth
Background
Nasopharyngeal carcinoma (NPC) is a type of malignant squamous cell tumour originating from the nasopharynx epithelium. Pentagalloylglucose (PGG) is a natural polyphenolic compound that exerts anticancer effects in many types of tumours. However, the role and underlying mechanism of PGG in NPC cells have not been fully defined.
Purpose
This study aimed to investigate the anticancer activity of PGG as well as the potential mechanism in NPC cells.
Methods
The effects of PGG on the proliferation, apoptosis and cell cycle distribution of CNE1 and CNE2 cells were assessed by MTT and flow cytometry assays. Cell migration was evaluated using wound healing and transwell assays. The expression of microtubule-associated protein 1 light chain 3 beta (LC3B) was observed by immunofluorescence staining. Western blotting was used to explore the levels of related proteins and signalling pathway components. Furthermore, the effects of PGG on NPC cell growth were analysed in a xenograft mouse model in vivo using cisplatin as a positive control.
Results
PGG dose-dependently inhibited the proliferation of CNE1 and CNE2 cells. PGG regulated the cell cycle by altering p53, cyclin D1, CDK2, and cyclin E1 protein levels. PGG induced apoptosis and autophagy in NPC cells and elevated the Bax/Bcl-2 ratio and the protein levels of LC3B. Moreover, PGG decreased NPC cell migration by increasing E-cadherin and decreasing N-cadherin, vimentin and CD44 protein levels. Mechanistically, PGG treatment downregulated p-mTOR and β-catenin expression but upregulated p-p38 MAPK and p-GSK3β expression. In addition, PGG significantly inhibited NPC cell tumour growth and lung metastasis in vivo.
Conclusion
PGG may suppress cell proliferation, induce apoptosis and autophagy, and decrease the metastatic capacity of NPC cells through the p38 MAPK/mTOR and Wnt/β-catenin pathways. The present study provides evidence for PGG as a potential therapy for NPC.
Background: H 2 S is the third gas transmitter affecting the growth, reproduction and survival of cancer cells. However, the H 2 S anticancer and antitumor mechanism still needs to be further studied. Methods: Here, FHS-1 was synthesized utilizing excited-state intramolecular proton transfer to detect H 2 S in MCF-7 cells, and investigated the effects of varying concentrations NaHS on apoptosis. Results: The study found that FHS-1 detects H 2 S levels with high selectivity and pH stability and that H 2 S may regulate apoptosis in MCF-7 cells through the p53/mTOR/STAT3 pathway. Conclusion: Researching the influence of H 2 S on apoptosis can serve as a theoretical foundation for future research into H 2 S-related anticancer medicines, and the H 2 S probe can be used as an effective cancer screening tool.
Breast cancer is one of the top-ranked malignant carcinomas associated with morbidity and mortality in women worldwide. Chemotherapy is one of the main approaches to breast cancer treatment. Breast cancer initially responds to traditional first- and second-line drugs (aromatase inhibitor, tamoxifen, and carboplatin), but eventually acquires resistance, and certain patients relapse within 5 years. Chemotherapeutic drugs also have obvious toxic effects. In recent years, natural products have been widely used in breast cancer research because of their low side effects, low toxicity, and good efficacy based on their multitarget therapy. Apoptosis, a programmed cell death, occurs as a normal and controlled process that promotes cell growth and death. Inducing apoptosis is an important strategy to control excessive breast cancer cell proliferation. Accumulating evidence has revealed that natural products become increasingly important in breast cancer treatment by suppressing cell apoptosis. In this study, we reviewed current studies on natural product–induced breast cancer cell apoptosis and summarized the proapoptosis mechanisms including mitochondrial, FasL/Fas, PI3K/AKT, reactive oxygen species, and mitogen-activated protein kinase–mediated pathway. We hope that our review can provide direction in the search for candidate drugs derived from natural products to treat breast cancer by promoting cell apoptosis.
In this study, the combined techniques of macroporous resin column chromatography and preparative high-performance liquid chromatography were applied for the separation of steroidal saponins from the stems and leaves of Paris polyphylla. Eight types of macroporous resins were examined using adsorption and desorption tests. Resin HPD-600 showed the maximum effectiveness and thus was selected for the first cleaning-up, in which 30% ethanol was used to remove the undesired constituents and 90% ethanol was used to elute the targets. Paris saponin II (36.2 mg) and dioscin (14.0 mg) were obtained from 500.5 mg of the extracts after purification by preparative high-performance liquid chromatography, with purities above 95% and yields of 81.87 and 72.89%, respectively. These results suggest that combined strategy is a useful and economic method to enrich and purify steroidal saponins from the stems and leaves of P. polyphylla.
Carotenoids are widely distributed in nature. They are present in all living organisms, from bacteria, yeast, marine, and freshwater organisms including microalgae, phytoplankton, crustaceans, and fish to higher plants and animals. Naturally occurring carotenoids are important sources of antioxidants, antiinflammatory and antitumor compounds. Epidemiological studies have shown a correlation between a high carotenoid intake in the diet with a reduced risk of colorectal, cervical, ovarian, and breast cancers. The mechanisms of carotenoids for cancer chemoprevention include nuclear receptors, growth factor signaling, effects on gap -junctional intercellular communication, cell cycle progression, differentiation-related proteins, retinoid-like receptors, antioxidant response element, and inflammatory cytokines. The present chapter focuses on the potential role of carotenoids for the treatment of breast cancer.
Autophagy is a ubiquitous mechanism for maintaining cellular homeostasis through the degradation of long-lived proteins, insoluble protein aggregates, and superfluous or damaged organelles. Dysfunctional autophagy is observed in a variety of human diseases. With advanced research into the role that autophagy plays in physiological and pathological conditions, targeting autophagy is becoming a novel tactic for disease management. Saponins are naturally occurring glycosides containing triterpenoids or steroidal sapogenins as aglycones, and some saponins are reported to modulate autophagy. Research suggests that saponins may have therapeutic and preventive efficacy against many autophagy-related diseases. Therefore, this review comprehensively summarizes and discusses the reported saponins that exhibit autophagy regulating activities. In addition, the relevant signaling pathways that the mechanisms involved in regulating autophagy and the targeted diseases were also discussed. By regulating autophagy and related pathways, saponins exhibit bioactivities against cancer, neurodegenerative diseases, atherosclerosis and other cardiac diseases, kidney diseases, liver diseases, acute pancreatitis, and osteoporosis. This review provides an overview of the autophagy-regulating activity of saponins, the underlying mechanisms and potential applications for managing various diseases.
Breast cancer is the most common and significant cancers in females regarding the loss of life quality. Similar to other cancers, one of the etiologic factors in breast cancer is DNA damage. A plethora of molecules are responsible for sensing DNA damage and mediating actions which lead to DNA repair, senescence, cell cycle arrest and if damage is unbearable to apoptosis. In each of these, aberrations leading to unrepaired damage was resulted in uncontrolled proliferation and cancer. Another cellular function is autophagy defined as a process eliminating of unnecessary proteins in stress cases involved in pathogenesis of cancer. Knowing their role in cancer, scholars have tried to develop strategies in order to target DDR and autophagy. Further, the interactions of DDR and autophagy plus their regulatory role on each other have been focused simultaneously. The present review study has aimed to illustrate the importance of DDR and autophagy in breast cancer according to the related studies and uncover the relation between DDR and autophagy and its significance in breast cancer therapy.
BACKGROUND
Bitter Melon Extract (BME) is widely used for the treatment of various diseases worldwide, due to its rich phytochemical and antioxidant content. The well-known anti-cancer drug, Paclitaxel (PAC) plays a major role in the treatment of various cancer types such as ovarian, breast, and lung cancer. Technetium-99m (99mTc) radiolabeled paclitaxel is emerging as an imaging probe for breast cancer in vivo. 99mTc labeled compounds have been attracting more scientific attention since the achievement of earlier researches in Nuclear Medicine. People consume several types of plant origin diet without knowing the interaction with radiolabeled compounds or radiopharmaceuticals.
OBJECTIVE
In the current study, we aimed to monitor potential effects of the BME on the uptake of 99mTc labeled Paclitaxel (99mTcPAC) on MCF-7 (ER+) and MDA-MB-231 (ER-) cell lines by using in vitro methods.
METHODS
BME was obtained by extraction of BM seeds by 80% ethanol. PAC was labeled with 99mTc by stannous chloride (SnCl2) as reducing agent. Cytotoxicity and incorporation assays were performed on MCF-7 and MDA-MB-231 cells within the cell culture studies.
RESULTS
The uptake value of 99mTc-PAC on MCF-7 cells at 240 minutes was 6.20% and BME treated 99mTc-PAC values was 17.39%.
CONCLUSION
It is observed that BME treatment has a significant effect on uptake of the 99mTc-PAC on MCF-7 cells which is a known estrogen receptor positive breast carcinoma cell line. It is concluded that this effect could be due to the estrogen receptor dependent interaction of BME.
Objectives:
Paris polyphylla var. yunnanensis (PPVY), a Chinese herb, has long been used for cancer treatment, and its steroidal saponins are suggested to exert an anti-tumor activity, however, the underlying mechanism is incompletely understood and their effect on bladder cancer (BC) remains unknown. The present study is thus designed to address these issues.
Material and methods:
Total steroidal saponins were extracted with ethanol from PPVY and used to treat BC cells (HT1197 and J82 carrying mutant p53). Gene expression was determined using qPCR and immunoblotting and cell cycle analyzed using flow cytometry. DNA damage response activation was assessed using immunofluorescence staining.
Results:
PPVY saponins treatment led to dose-dependent declines in the number of both HT1197 and J82 cells with IC50 approximately 1.2 μg/ml, which was coupled with strong growth arrest at G2/M phase and the activation of DNA damage response pathway. Moreover, the clonogenic potential of these cells was severely impaired even in the presence of low concentrations of PPVY saponins. Mechanistically, PPVY saponins induced the degradation of mutant p53 while stimulated CDKN1A gene transcription. Phosphorylated AKT was diminished in PPVY saponin-treated cells, but its specific inhibitor LY294002 exhibited significantly weaker efficacy in inducing CDKN1A expression than did PPVY saponins.
Conclusion:
PPVY saponins activate DNA damage response pathway, degrade mutant p53 and stimulate CDKN1A expression, thereby inhibiting BC cell growth. Given their poor absorption via oral administration, PPVY saponins may be applicable for intravesical instillations in BC treatment.
A series of 16 new diselenide-acylselenourea conjugates have been designed following the fragment-based drug strategy. Compound in vitro cytotoxic potential was evaluated against six human cancer cell lines and two non-malignant derived cell lines with the aim of determining their potency and selectivity. Nine derivatives exhibited GI50 values under 10 μM in at least four cancer cell lines. A clear gap situated phenyl substitution over heterocyclic moieties in terms of selectivity. Among carbocyclic compounds, derivatives 2 and 7 significantly inhibited cell growth of breast adenocarcinoma cells with GI50 values of 1.30 and 0.15 nM, respectively with selectivity indexes 12 and 121 times higher than those obtained for doxorubicin. Preliminary mechanistic studies indicated that compounds 2 and 7 induce cell cycle arrest and autophagy-dependent cell death evidenced by the blockage of cell death with pre-treatment with wortmannin and confirmed by the upregulation of the markers Beclin1 and LC3B in MCF-7 cells.
Traditional cancer therapy is mainly targeting on enhancing cell apoptosis, however, it is well established that many cancer cells are chemo-resistant and defective in apoptosis induction. Therefore, it may have important therapeutic implications to exploit some novel natural compounds based on non-apoptotic programmed cell death. Currently, accumulating evidence shows that the compounds from nature source can induce non-apoptotic programmed cell death in cancer cells, and therefore these natural compounds have gained a great promise for the future anticancer therapeutics. In this review, we will concentrate our efforts on the latest developments regarding major forms of non-apoptotic programmed cell death--autophagic cell death, necroptosis, ferroptosis, pyroptosis, glutamoptosis and exosome-associated cell death. Our increased understanding of the role of natural compounds in regulating non-apoptotic programmed cell death will hopefully provide prospective strategies for cancer therapy.
The aim of this work was to further investigate the anticancer potential of Juglans mandshurica Maxim, including the separation of active constituents and their anti-proliferative effects with underlying mechanism of action. Five alkaloids (1–5) were isolated from the bark of J. mandshurica. Among them, 1 showed the highest cytotoxic activities against Hep3B and HepG2 cells with an IC50 values of 61.80 and 56.24 μM, respectively. Therefore, the cellular mechanism involved 1 was subsequently studied. Our results showed that 1 markedly caused apoptosis and autophagy, but without cell cycle arrest in HepG2 cells. Interestingly, only autophagic cell death was induced in 1-treated Hep3B cells. It is concluded that the isolated alkaloids exerted a certain anti-hepatoma potential, and our results may provide a basis for the further investigation of the alkaloids extracted from J. mandshurica.
Endoplasmic reticulum (ER), principal but complex, functions as the pleiotropic organelle for proper protein folding, Ca²⁺ storage as well as lipid and carbohydrate metabolisms. Diverse microenviromental insults including, but not limited to, inflammatory reaction, glucose imbalance and hypoxia, elicit the accumulation of potentially toxic unfolded proteins in the ER lumen. Under the condition of these cellular threats, the autophagy with the well-orchestrated program containing over 30 autophagy-related genes (ATGs) might be initiated for degrading and recycling of the cumulative misfolded proteins and other related abnormal cytoplasmic components. The link between UPR and autophagy has been verified as the PERK-eIF2α-ATF4 signaling pathway by ongoing research, and the transcription factor C/EBP homologous (CHOP) mediated by ATF4 were further substantiated to regulate a dozen of ATG genes transcriptionally. Recent researches showed that the crosstalk between these signaling systems might mainly account for chemotherapy resistance in many cancers because the chemoresistant phenotypes are usually concomitant with increasing autophagy when drugs were administrated to trigger inflammatory microenvironment and other dyshomeostasis. We summarized recent researches in the molecular link between UPR and autophagy signaling pathways as well as the perspectives of potential inhibitors targeting the Achilles heel for further clinical use.
Vitexin, a flavonoids compound, is known to exhibit broad anti-oxidative, anti-inflammatory, analgesic, and antitumor activity in many cancer xenograft models and cell lines. The purpose of this study was to investigate the antitumor effects and underlying mechanisms of vitexin on hepatocellular carcinoma. In this study, we found that vitexin suppressed the viability of HCC cell lines (SK-Hep1 and Hepa1-6 cells) significantly. Vitexin showed cytotoxic effects against HCC cell lines in vitro by inducing apoptosis and inhibiting autophagy. Vitexin induced apoptosis in a concentration-dependent manner, and caused up-regulations of Caspase-3, Cleave Caspase-3, and a down-regulation of Bcl-2. The expression of autophagy-related protein LC3 II was significantly decreased after vitexin treatment. Moreover, western blot analysis presented that vitexin markedly up-regulated the levels of p-JNK and down-regulated the levels of p-Erk1/2 in SK-Hep1 cells and Hepa1-6 cells. Cotreatment with JNK inhibitor SP600125, we demonstrated that apoptosis induced by vitexin was suppressed, while the inhibition of autophagy by vitexin was reversed. The results of colony formation assay and mouse model confirmed the growth inhibition role of vitexin on HCC in vitro and in vivo. In conclusion, vitexin inhibits HCC growth by way of apoptosis induction and autophagy suppression, both of which are through JNK MAPK pathway. Therefore, vitexin could be regarded as a potent therapeutic agent for the treatment of HCC.
Phosphatidylinositide 3 kinases (PI3Ks) and their downstream mediators AKT and mammalian target of rapamycin (mTOR) constitute the core components of the PI3K/AKT/mTOR signalling cascade, regulating cell proliferation, survival and metabolism. Although these functions are well-defined in the context of tumorigenesis, recent studies - in particular those using pluripotent stem cells - have highlighted the importance of this pathway to development and cellular differentiation. Here, we review the recent in vitro and in vivo evidence for the role PI3K/AKT/mTOR signalling plays in the control of pluripotency and differentiation, with a particular focus on the molecular mechanisms underlying these functions.
Multifaceted activities of class I phosphatidylinositol 3-kinase (PI3K) inhibitor ZSTK474 were investigated on human breast cancer cell MCF-7. ZSTK474 inhibited proliferation of MCF-7 cells potently. Flow cytometric analysis indicated that ZSTK474 induced cell cycle arrest at G1 phase, but no obvious apoptosis occurred. Western blot analysis suggested that blockade of PI3K/Akt/GSK-3β/cyclin D1/p-Rb pathway might contribute to the G1 arrest induced. Moreover, we demonstrated that ZSTK474 induced autophagy in MCF-7 cells by use of various assays including monodansylcadaverine (MDC) staining, transmission electron microscopy (TEM), tandem mRFP-GFP-LC3 fluorescence microscopy, and western blot detection of the autophagy protein markers of LC3B II, p62 and Atg 5. Inhibition of class I PI3K and the downstream mTOR might be involved in the autophagy-inducing effect. Combinational use of ZSTK474 and autophagy inhibitors enhanced cell viability, suggesting ZSTK474-induced autophagy might contribute to the antitumor activity. Our report supports the application of ZSTK474, which is being evaluated in clinical trials, for breast cancer therapy.
Autophagy is an evolutionarily conserved process in eukaryotes that eliminates harmful components and maintains cellular homeostasis in response to a series of extracellular insults. However, these insults may trigger the downstream signaling of another prominent stress responsive pathway, the STAT3 signaling pathway, which has been implicated in multiple aspects of the autophagic process. Recent reports further indicate that different subcellular localization patterns of STAT3 affect autophagy in various ways. For example, nuclear STAT3 fine tunes autophagy via the transcriptional regulation of several autophagy-related genes such as BCL2 family members, BECN1, PIK3C3, CTSB, CTSL, PIK3R1, HIF1A, BNIP3, and microRNAs with targets of autophagy modulators. Cytoplasmic STAT3 constitutively inhibits autophagy by sequestering EIF2AK2 as well as by interacting with other autophagy-related signaling molecules such as FOXO1 and FOXO3. Additionally, the mitochondrial translocation of STAT3 suppresses autophagy induced by oxidative stress and may effectively preserve mitochondria from being degraded by mitophagy. Understanding the role of STAT3 signaling in the regulation of autophagy may provide insight into the classic autophagy model and also into cancer therapy, especially for the emerging targeted therapy, because a series of targeted agents execute antitumor activities via blocking STAT3 signaling, which inevitably affects the autophagy pathway. Here, we review several of the representative studies and the current understanding in this particular field.
Our previous study has shown that ampelopsin (AMP), a flavonol mainly existed in Ampelopsis grossedentata, could induce cell death in human breast cancer cells via reactive oxygen species generation and endoplasmic reticulum (ER) stress pathway. Here, we examined whether autophagy is activated in AMP- treated breast cancer cells and, if so, what the exact role and underlying molecular of autophagy in AMP-induced cell death. Our results showed AMP treatment activated autophagy in MDA-MB-231 and MCF-7 breast cancer cells as evidenced by the accumulation of autophagosomes, an increase of microtubule- associated protein 1 light chain 3 beta-2 (LC3B-II) and the conversion of LC3B-I to LC3B-II, the degradation of the selective autophagic target p62/SQSTM1, and the formation of green fluorescent protein (GFP)-LC3 puncta. Blockage of autophagy augmented AMP-induced cell death, suggesting that autophagy has cytoprotective effects. Meanwhile, AMP treatment suppressed Akt-mammalian target of rapamycin (mTOR) pathway as evidenced by dose- and time- dependently decreased the phosphorylation of Akt, mTOR and ribosomal protein S6 kinase (p70S6K), whereas Akt activator insulin-like growth factor-1 (IGF-1) pretreatment partially restored Akt-mTOR pathway inhibited by AMP and decreased AMP-inuduced autophagy, signifying that AMP activated autophagy via inhibition of the Akt-mTOR pathway. Additionally, blocking ER stress not only reduced autophagy induction, but also alleviated inhibition of Akt-mTOR pathway induced by AMP, suggesting that activation of ER stress was involved in induction of autophagy and inhibition of Akt-mTOR pathway. Taken together, these findings indicate that AMP induces protective autophagy in human breast cancer cells through Akt-mTOR pathway via ER stress.This article is protected by copyright. All rights reserved.
Polyphyllins, a major component of Rhizoma paridis, have been extensively used in non‑small cell lung cancer (NSCLC). The aim of the present study was to evaluate the effects of Paris saponin I (PSI) on a panel of gefitinib‑resistant NSCLC cell lines and its inhibition of tumor growth in a nude mouse model. The MTT assay was used to assess growth inhibition. The cell cycle was analyzed using flow cytometry and apoptosis was assessed using Annexin V/propidium iodide staining. The morphology of the apoptotic cells was determined by transmission electron microscopy. The protein expression levels of B‑cell lymphoma 2 (Bcl‑2), Bcl‑2‑associated X protein (Bax) and caspase‑3 were detected using western blot analysis. In addition, the glucose metabolism in tumor‑bearing mice was evaluated using 18F‑fludeoxyglucose (FDG) micro‑positron emission tomography imaging. The PSI‑induced growth inhibition rate was observed to significantly increase in a time‑ and dose‑dependent manner. Furthermore, PSI induced significant G2/M‑phase arrest and apoptosis. The expression levels of Bcl‑2 decreased, while those of Bax and caspase‑3 increased following PSI treatment. 18F‑FDG‑uptake in the PSI treatment groups was significantly decreased compared with that in the control group in vivo. In conclusion, PSI is a potent antitumor agent that acts by inhibiting the proliferation of gefitinib‑resistant cells, and has potential as a candidate for a natural drug for gefitinib‑resistant therapy. PSI‑induced apoptosis, which occurred via multiple pathways, including G2/M‑phase arrest and upregulation of the Bax/Bcl‑2 ratio and caspase‑3 expression, ultimately led to cell death and tumor inhibition.
The phosphoinositide 3-kinase (PI3K) family is important to nearly all aspects of cell and tissue biology and central to human cancer, diabetes and aging. PI3Ks are spatially regulated and multifunctional, and together, act at nearly all membranes in the cell to regulate a wide range of signaling, membrane trafficking and metabolic processes. There is a broadening recognition of the importance of distinct roles for each of the three different PI3K classes (I, II and III), as well as for the different isoforms within each class. Ongoing issues include the need for a better understanding of the in vivo complexity of PI3K regulation and cellular functions. This Cell Science at a Glance article and the accompanying poster summarize the biochemical activities, cellular roles and functional requirements for the three classes of PI3Ks. In doing so, we aim to provide an overview of the parallels, the key differences and crucial interplays between the regulation and roles of the three PI3K classes.
This study sought to investigate the prognostic value of the autophagy marker microtubule-associated protein chain 3B (LC3B) in patients with residual tumors after neoadjuvant chemotherapy (NCT) for locally advanced breast cancer (LABC).
The expression of LC3B in residual breast cancer cells was assessed by immunohistochemistry in surgical specimens from 229 patients diagnosed with histologically proven invasive breast cancer. All patients underwent NCT followed by mastectomy and were considered non-pathological complete responders (non-pCR) after a pathological evaluation. The prognostic value of various clinicopathologic factors was evaluated.
The LC3B density was similar between the peripheral and central area of the tumors (P=0.328) but was significantly lower in the extratumoral area (P<0.001 and P<0.001, respectively). Furthermore, LC3B density, which correlated with Beclin-1 expression, Ki-67 index, and breast cancer subtype, served as an independent prognostic factor for both relapse-free survival (RFS) (P=0.012) and overall survival (OS) (P=0.008); the prognostic value of LC3B was most significant in triple-negative patients. Using a combination of LC3B expression and the status of residual involved lymph nodes, the patients were classified into 4 groups with different risks of relapse and death (P<0.001 for RFS and P=0.003 for OS).
LC3B can be used as a prognostic marker in non-pCR patients after NCT for breast cancer, which highlights the importance of autophagy in the biological behavior of chemo-resistant cancer cells. Furthermore, evaluating and targeting autophagy in the neoadjuvant setting may help prevent disease relapse in non-pCR patients.
Deltonin, a steroidal saponin isolated from Dioscorea zingiberensis Wright, exhibits high cytotoxic activity in cancer cells. In the present study, the effects of deltonin on cell proliferation and apoptosis were evaluated in the MDA‑MB‑231 human breast carcinoma cell line. Following treatment with deltonin, the viability of MDA‑MB‑231 cells was analyzed using MTT assay and apoptosis, mitochondrial membrane potential (∆Ψm) alternation and intracellular reactive oxygen species (ROS) generation was determined by flow cytometry. In addition, western blot analysis was performed to examine the expression of apoptosis‑associated proteins. The results demonstrated that deltonin induced apoptosis in MDA‑MB‑231 cells in a time‑ and concentration‑dependent manner. Apoptosis was associated with depolarization of ∆Ψm and time‑dependent ROS generation. Deltonin treatment also resulted in Bax upregulation, Bcl-2 downregulation, activation of caspase‑3 and ‑8 and poly (ADP ribose) polymerase cleavage. Decreased levels of phosphorylated extracellular signal‑regulated kinase (ERK) and phosphorylated AKT were also observed. Results indicate that the proliferation inhibitory effect of deltonin is associated with its apoptosis‑inducing effect, which may correlate with ROS‑mediated mitochondrial dysfunction as well as activation of the ERK/AKT signaling pathways. Therefore, deltonin may be a potential chemotherapeutic agent for the treatment of breast cancer.
Autofagia jest procesem degradacji wielkocząsteczkowych składników cytoplazmy, zwłaszcza białek o długim okresie półtrwania oraz całych organelli. W komórkach eukariotycznych, spośród trzech postaci autofagii, najlepiej poznana jest makroautofagia. W czasie makroautofagii (zwanej dalej autofagią) fragment cytoplazmy zostaje otoczony przez formującą się podwójną błonę tworzącego się pęcherzyka, zwanego autofagosomem. Następnie zawartość autofagosomu po jego połączeniu się z lizosomem ulega degradacji. Proces autofagii odpowiedzialny jest za utrzymanie wewnątrzkomórkowej homeostazy i umożliwia przeżycie komórkom w warunkach stresowych. Autofagia odgrywa również rolę w patogenezie wielu chorób, w tym w procesie nowotworzenia. W komórkach nowotworowych autofagia może pełnić dwojaką rolę, jako proces zaangażowany w przeżycie lub śmierć komórki. W większości przypadków, autofagia indukowana terapią w komórkach nowotworowych umożliwia im przeżycie, promując rozwój nowotworu i potencjalnie prowadząc do występowania oporności na leczenie. Autofagia może również pełnić rolę supresora transformacji nowotworowej i wywołując apoptozę, może zwiększać skuteczność leczenia. Dla powodzenia terapii przeciwnowotworowej istotne jest, aby określić typ komórek nowotworowych podatnych na autofagię w odpowiedzi na podjęty rodzaj leczenia oraz aby określić, czy w danym przypadku autofagia przyczynia się do skuteczności zastosowanej terapii, czy raczej do oporności na nią. W pracy omówiono molekularny mechanizm autofagii oraz najważniejsze szlaki sygnałowe uczestniczące w regulacji przebiegu tego procesu w komórkach nowotworowych. Omówiona została również dwojaka rola autofagii w procesie nowotworzenia oraz skutki zarówno indukcji, jak i inhibicji autofagii w terapii przeciwnowotworowej.
To investigate the anti-tumor effects of Paris chinensis dioscin (PCD) and mechanisms regarding cell cycle regulation and apoptosis in human gastric cancer SGC-7901 cells.
Cell viability was analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Cell apoptosis was evaluated by flow cytometry and laser scanning confocal microscope (LSCM) using Annexin-V/propidium iodide (PI) staining, and the cell cycle was evaluated using PI staining with flow cytometry. Intracellular calcium ions were detected under fluorescence microscope. The expression of cell cycle and apoptosis-related proteins cyclin B1, CDK1, cytochrome C and caspase-3 was measured by immunohistochemical staining.
PCD had an anti-proliferation effect on human gastric cancer SGC-7901 cells in a dose- and time-dependent manner. After treatment of SGC-7901 cells with PCD, apoptosis appeared in SGC-7901 cells. Morphological changes typical of apoptosis were also observed with LSCM by Annexin V/PI staining, and the cell number of the G0/G1 phase was decreased, while the number of cells in the G2/M phase was increased. Cell cycle-related proteins, such as cyclin B1 and CDK1, were all down-regulated, but caspase-3 and cytochrome C were up-regulated. Moreover, intracellular calcium accumulation occurred in PCD-treated cells.
G2/M phase arrest and apoptosis induced by PCD are associated with the inhibition of CDK-activating kinase activity and the activation of Ca(2+)-related mitochondrion pathway in SGC-7901 cells.
Living cells are adaptive self-sustaining systems. They strictly depend on the sufficient supply of oxygen, energy, and nutrients from the outside in order to sustain their internal organization. However, as autonomous entities they are able to monitor and appropriately adapt to any critical fluctuation in their environment. In the case of insufficient external nutrient supply or augmented energy demands, cells start to extensively digest their own interior. This process, known as macroautophagy, comprises the transport of cytosolic portions and entire organelles to the lysosomal compartment via specific double-membrane vesicles, called autophagosomes. Although extensively upregulated under nutrient restriction, a low level of basal autophagy is likewise crucial in order to sustain the cellular homeostasis. On the other hand, cells have to avoid excessive and enduring self-digestion. The delicate balance between external energy and nutrient supply and internal production and consumption is a demanding task. The complex protein network that senses and precisely reacts to environmental changes is thus mainly regulated by rapid and reversible posttranslational modifications such as phosphorylation. This review focuses on the serine/threonine protein kinases AMP-activated protein kinase, mammalian target of rapamycin (mTOR), and unc-51-like kinase 1/2 (Ulk1/2), three interconnected major junctions within the autophagy regulating signaling network.
A group of phosphoinositide 3-kinase (PI3K) inhibitors, such as 3-methyladenine (3-MA) and wortmannin, have been widely used as autophagy inhibitors based on their inhibitory effect on class III PI3K activity, which is known to be essential for induction of autophagy. In this study, we systematically examined and compared the effects of these two inhibitors on autophagy under both nutrient-rich and deprivation conditions. To our surprise, 3-MA is found to promote autophagy flux when treated under nutrient-rich conditions with a prolonged period of treatment, whereas it is still capable of suppressing starvation-induced autophagy. We first observed that there are marked increases of the autophagic markers in cells treated with 3-MA in full medium for a prolonged period of time (up to 9 h). Second, we provide convincing evidence that the increase of autophagic markers is the result of enhanced autophagic flux, not due to suppression of maturation of autophagosomes or lysosomal function. More importantly, we found that the autophagy promotion activity of 3-MA is due to its differential temporal effects on class I and class III PI3K; 3-MA blocks class I PI3K persistently, whereas its suppressive effect on class III PI3K is transient. Because 3-MA has been widely used as an autophagy inhibitor in the literature, understanding the dual role of 3-MA in autophagy thus suggests that caution should be exercised in the application of 3-MA in autophagy study.
Curcumin has a potent anticancer effect and is a promising new therapeutic strategy. We previously demonstrated that curcumin induced non-apoptotic autophagic cell death in malignant glioma cells in vitro and in vivo. This compound inhibited the Akt/mammalian target of rapamycin/p70 ribosomal protein S6 kinase pathway and activated the extracellular signal-regulated kinases 1/2 thereby inducing autophagy. Interestingly, activation of the first pathway inhibited curcumin-induced autophagy and cytotoxicity, whereas inhibition of the latter pathway inhibited curcumin-induced autophagy and induced apoptosis, thus augmenting the cytotoxicity of curcumin. These results imply that these two autophagic pathways have opposite effects on curcumin's cytotoxicity. However, inhibition of nuclear factor kappaB, which is the main target of curcumin for its anticancer effect, was not observed in malignant glioma cells. These results suggest that autophagy but not nuclear factor kappaB plays a central role in curcumin anticancer therapy and warrant further investigation toward application in patients with malignant gliomas. Here, we discuss the therapeutic role of two autophagic pathways influenced by curcumin.
Drug resistance in breast cancer remains a major obstacle of clinical therapy. We found that suppression of ELK3 in the triple negative breast cancer cell line MDA-MB-231 impaired autophagy and led to a hypersensitive response to doxorubicin treatment. In ELK3-knockdown MDA-MB-231 cells (ELK3 KD), autophagy was not activated under starvation conditions, which is a major stimulus of autophagy activation. We revealed that activation of the PI3K/Akt pathway was the main cause of impaired autophagy in ELK3 KD. Our results suggest that targeting ELK3 may be a potential approach to overcome doxorubicin resistance in breast cancer therapeutics.
Breast cancer is the most common cancer among women worldwide yet successful treatment remains a clinical challenge. Ivermectin, a broad-spectrum antiparasitic drug, has recently been characterized as a potential anticancer agent due to observed anti-tumor effects. However, the molecular mechanisms involved remain poorly understood. Here, we report a role for ivermectin in breast cancer suppression by activating cytostatic autophagy both in vitro and in vivo. Mechanistically, ivermectin-induced autophagy in breast cancer cells is associated with decreased P21-activated kinase 1 (PAK1) expression via the ubiquitination-mediated degradation pathway. The inhibition of PAK1 decreases the phosphorylation level of Akt, resulting in the blockade of the Akt/mTOR signaling pathway. In breast cancer xenografts, the ivermectin-induced cytostatic autophagy leads to suppression of tumor growth. Together, our results provide a molecular basis for the use of ivermectin to inhibit the proliferation of breast cancer cells, and indicate that ivermectin is a potential option for the treatment of breast cancer.
As much as the cellular viability is important for the living organisms, the elimination of unnecessary or damaged cells has the opposite necessity for the maintenance of homeostasis in tissues, organs and the whole organism. Apoptosis, a type of cell death mechanism, is controlled by the interactions between several molecules and responsible for the elimination of unwanted cells from the body. Apoptosis can be triggered by intrinsically or extrinsically through death signals from the outside of the cell. Any abnormality in apoptosis process can cause various types of diseases from cancer to auto-immune diseases. Different gene families such as caspases, inhibitor of apoptosis proteins, B cell lymphoma (Bcl)-2 family of genes, tumor necrosis factor (TNF) receptor gene superfamily, or p53 gene are involved and/or collaborate in the process of apoptosis. In this review, we discuss the basic features of apoptosis and have focused on the gene families playing critical roles, activation/inactivation mechanisms, upstream/downstream effectors, and signaling pathways in apoptosis on the basis of cancer studies. In addition, novel apoptotic players such as miRNAs and sphingolipid family members in various kind of cancer are discussed.
Kaempferol has been identified as a potential cancer therapeutic agent by an increasing amount of evidences. However, the changes in the topography of cell membrane induced by kaempferol at subcellular- or nanometer-level were still unclear. In this work, the topographical changes of cytomembrane in human cervical cancer cell (SiHa) induced by kaempferol, as well as the role of kaempferol in apoptosis induction and its possible mechanisms, were investigated. At the macro level, MTT assays showed that kaempferol inhibited the proliferation of SiHa cells in a time- and dose-dependent manner. Flow cytometry analysis demonstrated that kaempferol could induce SiHa cell apoptosis, mitochondrial membrane potential disruption, and intracellular free calcium elevation. At the micro level, fluorescence imaging by laser scanning confocal microscopy (LSCM) indicated that kaempferol could also destroy the networks of microtubules. Using high resolution atomic force microscopy (AFM), we determined the precise changes of cellular membrane induced by kaempferol at subcellular or nanometer level. The spindle-shaped SiHa cells shrank after kaempferol treatment, with significantly increased cell surface roughness. These data showed structural characterizations of cellular topography in kaempferol-induced SiHa cell apoptosis and might provide novel integrated information from macro to nano level to assess the impact of kaempferol on cancer cells, which might be important for the understanding of the anti-cancer mechanisms of drugs. SCANNING 9999:1-10, 2016. © 2016 Wiley Periodicals, Inc.
Breast cancer is one of the most common cancers among women with high mortality and morbidity. The present study was aimed to investigate the cytotoxic mechanism of SZC015, a synthetic oleanolic acid (OA) derivative, in MCF-7 human breast cancer cells. SZC015 reduced MCF-7 cell viability with an IC50 value of only 24.19 μM at 24h by activating both apoptosis and autophagy pathways. More specifically, we found that SZC015 was able to activate intrinsic apoptosis, which was proved by activations of caspase3, caspase9, release of cytochrome C, cleavage of PARP and increasing ratio of Bax/Bcl-2. SZC015 induced autophagy in MCF-7 cells evidenced by the increase of LC3II/LC3I and up-regulation of Atg5 and beclin1. Moreover, these two cell death pathways were modulated by inhibiting phosphatidylinositide 3-kinase/protein kinase B/mammalian target of rapamycin/nuclear factor-κB (PI3K/Akt/mTOR/NF-κB), mitogen-activated protein kinase (MAPK) signaling pathways. SZC015 also induced S phase cell cycle arrest in MCF-7 cells. Furthermore, analysis of topoisomerase I (Top I) and topoisomerase IIα (Top IIα) proteins suggested that SZC015 may interfere the DNA topological phenomenon. The computer-assisted molecular docking study also showed SZC015 had lower interaction energy with Top I and Top IIα than that of OA. In conclusion, the current study revealed SZC015 played an important role in the regulation of autophagy and apoptosis in breast cancer cells.
Autophagy played a crucial role for survival when cells were sufiering from nutrient deprivation, as autophagy could engulf and degenerate macromolecules to provide new nutrients and energy. Autophagy also plays an essential role in maintaining cellular homeostasis, which was activated in response to the cellular stresses in hypertensive heart disease. Interestingly, many studies had proven that the baseline and up-regulation of autophagy played a beneficial role in myocardial hypertrophy while other studies found that up-regulated autophagy was associated with myopathies. In this review, we showed the signalling pathways which were involved in myocardial hypertrophy. Besides, we talked about the protective as well as harmful efiects of autophagy in myocardial hypertrophy. Finally, we proposed the possible reasons of dual efiects of autophagy in hypertrophy, including the degree of the activation, the stage of the disease and the signalling pathways responsible for the activation of autophagy, etc.
Autophagy is an intracellular bulk degradation system that is highly conserved in eukaryotes. The discovery of autophagy-related ('ATG') proteins in the 1990s greatly advanced the mechanistic understanding of autophagy and clarified the fact that autophagy serves important roles in various biological processes. In addition, studies have revealed other roles for the autophagic machinery beyond autophagy. In this Review, we introduce advances in the knowledge of the roles of autophagy and its components in immunity, including innate immunity, inflammatory responses and adaptive immunity.
Twelve compounds were isolated from the rhizome of Paris mairei Lévl by silica gel, Sephadex LH-20 and ODS col-umn chromatographies. The structure elucidation was accomplished by ESI-MS and NMR methods. These compounds were identified as lupeol(1), lup-20(29) -ene-3β-yl octacosanoate(2), palmitic acid(3), glyceryl α-mono-palmitate(4), α-spinasterol(5), diosgenin (6), (25R) diosgenin-3-O-α-L-rhamnopyranosyl (1--> 4) -α-L-rhamnopyranosyl (1 --> 4) - [α-L-rhamnopyranosyl(1 --> 2)] -β-D-glucopyranoside(7), pennogenin(8), pennogenin-3-O-β-D-glucopyranosyl(1 -->3) - [α-L-rhamnopyranosyl(1 --> 2)] -β-D-glucopyranoside(9), flazin(10), calonysterone(11), and isorhamnetin-3-O-β-gentiobioside(12). Compounds 1-5,10-11 were isolated from the genus Paris for the first time, and all compounds were isolated from this plant for the first time.
While acute effects of toxic radiation doses on intestine are well established, we are yet to acquire a complete spectrum of sub-lethal radiation-induced chronic intestinal perturbations at the molecular level. We investigated persistent effects of a radiation dose (2 Gy) commonly used as a daily fraction in radiotherapy on oxidants and anti-oxidants, and autophagy pathways, which are interlinked processes affecting intestinal homeostasis. Six to eight weeks old C57BL/6J mice (n = 10) were exposed to 2 Gy �-ray. Mice were euthanized two or twelve months after radiation, intestine surgically removed, and flushed using sterile PBS. Parts of the intestine from jejunal–ilial region were fixed, frozen, or used for intestinal epithelial cell(IEC) isolation. While oxidant levels and mitochondrial status were assessed in isolated IEC, autophagy and oxidative stress related signaling pathways were probed in frozen and fixed samples using PCR-based expression arrays and immunoprobing. Radiation exposure caused significant alterations in the expression level of 26 autophagy and 17 oxidative stress related genes. Immunoblot results showed decreasedBeclin1 and LC3-II and increased p62, PI3K/Akt, and mTOR. Flow cytometry data showed increased oxidant production and compromised mitochondrial integrity in irradiated samples. Immunoprobingof intestinal sections showed increased 8-oxo-dG and nuclear PCNA, and decreased autophagosome marker LC3-II in IEC after irradiation. We show that sub-lethal radiation could persistently downregulate anti-oxidants and autophagy signaling, and upregulate oxidant production and proliferative signaling.Radiation-induced promotion of oxidative stress and downregulation of autophagy could work in tandem to alter intestinal functions and have implications for post-radiation chronic gastrointestinal diseases.
Dioscin, a saponin extracted from the roots of Polygonatum zanlanscianense, shows several bioactivities such as antitumor, antifungal, and antiviral properties. Although, dioscin is already known to induce cell death in variety cancer cells, the molecular basis for dioscin-induced cell death was not definitely known in cancer cells. In this study, we found that dioscin treatment induced cell death in dose-dependent manner in breast cancer cells such as MDA-MB-231, MDA-MB-453, and T47D cells. Dioscin decreased expressions of Bcl-2 and cIAP-1 proteins, which were down-regulated at the transcriptional level. Conversely, Mcl-1 protein level was down-regulated by facilitating ubiquitin/proteasome-mediated Mcl-1 degradation in dioscin-treated cells. Pretreatment with z-VAD fails to attenuate dioscin-induced cell death as well as caspase-mediated events such as cleavages of procaspase-3 and PARP. In addition, dioscin treatment increased the population of annexin V positive cells and induced DNA fragmentation in a dose-dependent manner in MDA-MB-231 cells. Furthermore, apoptosis inducing factor (AIF) was released from the mitochondria and translocated to the nucleus. Suppression in AIF expression by siRNA reduced dioscin-induced apoptosis in MDA-MB-231 cells. Taken together, our results demonstrate that dioscin-induced cell death was mediated via AIF-facilitating caspase-independent pathway as well as down-regulating anti-apoptotic proteins such as Bcl-2, cIAP-1, and Mcl-1 in breast cancer cells.
Paris Saponin II (PSII) is an active component of Rhizoma Paridis-an essential ingredient in traditional Chinese herbal medicines. PSII can induce cytotoxic effects in cancer cells and inhibit ovarian cancer growth. Since pathological angiogenesis (henceforth, angiogenesis) is often associated with gynecological cancers, here, we investigated whether PSII renders effects on angiogenesis and examined possible molecular mechanisms underlying the effects of PSII.
The effects of PSII on the biofunctions of endothelial cells (EC), the crucial components of blood vessels, were examined by standardized angiogenesis in vitro and ex vivo assays, Western blot analysis, ELISA, and kinase assay. Angiogenesis in a xenograft mouse model of ovarian cancer was evaluated by color Doppler ultrasound and immunohistochemistry.
PSII exerted marked inhibitory effect on the growth of VEGF-stimulated human umbilical vein endothelial cells in a dose-time-dependent manner, inhibited cell's motility, and interfered with tubulogenesis. PSII also blocked microvessel outgrowth in a rat aortic ring assay and compromised angiogenesis in a mouse model of ovarian carcinoma using either SKOV3 or HOC-7 cell lines. VEGF levels in PSII-treated EC and tumor cells were reduced. In EC, PSII blocked the activation of VEGFR2 in dose-dependent manner leading to the reduction of VEGF-induced phosphorylation on several intracellular pro-angiogenic kinase, including the extracellular signal-related kinase, Src family kinase, focal adhesion kinase, and AKT kinase.
The results provided the first insight into the anti-angiogenesis properties of Saponin family in solid tumors and suggested a promising therapeutic potential of PSII in the ovarian cancer treatment.
Autophagy plays an important role in cellular homeostasis through the disposal and recycling of cellular components. Cancer stem cells (CSCs) play major roles in cancer initiation, progression, and drug resistance. Rottlerin (Rott) is an active molecule isolated from Mallotus philippinensis, a medicinal plant used in Ayurvedic Medicine for anti-allergic and anti-helminthic treatments, demonstrates anticancer activities. However, the molecular mechanisms by which it induces autophagy in prostate CSCs have not been examined. The main objective of the paper was to examine the molecular mechanisms by which Rott induces autophagy in prostate CSCs. Autophagy was measured by the lipid modification of light chain-3 (LC3) and the formation of autophagosomes. Apoptosis was measured by flow cytometer analysis. The Western blot analysis was used to examine the effects of Rott on the expression of PI3K, phosphorylation of Akt, phosphorylation of mTOR, and phosphorylation of AMPK in pros CSCs. RNAi technology was used to inhibit the expression of Beclin-1 and ATG-7. Rott induced the lipid modification of light chain-3 (LC3) and the formation of autophagosomes after 24 h of Rott treatment in prostate CSCs. Rott-treated prostate CSCs induced transition from LC3-I to LC3-II, a hall mark of autophagy. Rott also induced the expression of Atg5, Atg7, Atg12 and Beclin-1 proteins during autophagy. The knock-down of Atg7 and Beclin-1 blocked Rott-induced autophagy. Furthermore, Rott induced AMPK phosphorylation was blocked by 3-MA, Baf and CHX. In addition, inhibition of AMPK expression by shRNA blocked Rott induced autophagy. In conclusion, a better understanding of the biology of autophagy and the pharmacology of autophagy modulators has the potential for facilitating the development of autophagy-based therapeutic interventions for prostate cancer.
In this paper the convergence behavior of shunting inhibitory cellular neural networks with unbounded delays and time-varying coefficients are considered. Some sufficient conditions are established to ensure that the solutions of the networks converge locally exponentially to the zero point, which are new and complement of previously known results.
Dioscin, a natural product obtained from medicinal plants shows lipid-lowering, anti-cancer and hepatoprotective effects. However, the effect of it on glioblastoma is unclear. In this study, dioscin significantly inhibited proliferation of C6 glioma cells and caused reactive oxygen species (ROS) generation and Ca(2+) release. ROS accumulation affected levels of malondialdehyde, nitric oxide, glutathione disulfide and glutathione, and caused cell apoptosis. In addition, ROS generation caused mitochondrial damage including structural changes, increased mitochondrial permeability transition and decreased mitochondria membrane potential, which led to the release of cytochrome C, nuclear translation of programmed cell death-5 and increased activities of caspase-3, 9. Simultaneously, dioscin down-regulated protein expression of Bcl-2, Bcl-xl, up-regulated expression of Bak, Bax, Bid and cleaved poly (ADP-ribose) polymerase. Also, oxygen stress induced S-phase arrest of cancer cells by way of regulating expression of DNA Topo I, p53, CDK2 and Cyclin A and caused DNA damage. In a rat allograft model, dioscin significantly inhibited tumor size and extended the life cycle of the rats. In conclusion, dioscin shows noteworthy anti-cancer activity on glioblastoma cells by promoting ROS accumulation, inducing DNA damage and activating mitochondrial signal pathways. Ultimately, we believe dioscin has promise as a new therapy for the treatment of glioblastoma.
The purpose of this study was to investigate the ameliorating effect of dioscin (1) on multidrug resistance (MDR) in adriamycin (ADR)-resistant erythroleukemic cells (K562/adriamycin, K562/ADR) and to clarify the molecular mechanisms involved. High levels of multidrug resistance 1 (MDR1) mRNA and protein and reduced ADR retention were found in K562/ADR cells compared with parental cells (K562). Dioscin (1), a constituent of plants in the genus Discorea, significantly inhibited MDR1 mRNA and protein expression and MDR1 promoter and nuclear factor κ-B (NF-κB) activity in K562/ADR cells. MDR1 mRNA and protein suppression resulted in the subsequent recovery of intracellular drug accumulation. Additionally, inhibitor κB-α (IκB-α) degradation was inhibited by 1. Dioscin (1) reversed ADR-induced MDR by down-regulating MDR1 expression by a mechanism that involves the inhibition of the NF-κB signaling pathway. These findings provide evidence to support the further investigation of the clinical application of dioscin (1) as a chemotherapy adjuvant.
BCL-2 and related family members such as BCL-XL are anti-apoptotic proteins that are being pharmacologically targeted to potentiate apoptosis as an anticancer strategy. However, achieving efficacy while minimizing unwanted toxicity has remained a challenge.
Aims:
To investigate the relationship between the expression of autophagy-related proteins, including beclin-1, light chain (LC) 3A, LC3B, and p62, and prognosis in invasive breast cancer.
Methods and results:
We constructed tissue microarrays from the breast cancer cells of 489 patients, and classified molecular subtypes using surrogate immunohistochemical stains. The tumoral expression levels of LC3A and LC3B were highest in triple-negative breast cancer (TNBC) (P < 0.001), whereas these types of tumour had the lowest expression levels of these markers in the stroma (P = 0.005 and P < 0.001, respectively). Cytoplasmic beclin-1 expression was highest in TNBC, but nuclear expression was lowest (P < 0.001). p62 cytoplasmic and nuclear expression were highest in HER2-type tumours (P = 0.001 and P < 0.001, respectively). Tumoral LC3A and LC3B expression were associated with high histological grade (P < 0.001, and P < 0.028, respectively), but nuclear p62 expression was associated with lower histological grade (P = 0.004).
Conclusions:
Autophagy-related markers are differentially expressed according to the molecular subtype of breast cancer. In particular, expression of LC3A, LC3B and beclin-1 was highest in TNBC tumour cells, whereas that of LC3A and LC3B in the tumour stroma was lowest in TNBC.
This review is an updated and expanded version of the three prior reviews that were published in this journal in 1997, 2003, and 2007. In the case of all approved therapeutic agents, the time frame has been extended to cover the 30 years from January 1, 1981, to December 31, 2010, for all diseases worldwide, and from 1950 (earliest so far identified) to December 2010 for all approved antitumor drugs worldwide. We have continued to utilize our secondary subdivision of a "natural product mimic" or "NM" to join the original primary divisions and have added a new designation, "natural product botanical" or "NB", to cover those botanical "defined mixtures" that have now been recognized as drug entities by the FDA and similar organizations. From the data presented, the utility of natural products as sources of novel structures, but not necessarily the final drug entity, is still alive and well. Thus, in the area of cancer, over the time frame from around the 1940s to date, of the 175 small molecules, 131, or 74.8%, are other than "S" (synthetic), with 85, or 48.6%, actually being either natural products or directly derived therefrom. In other areas, the influence of natural product structures is quite marked, with, as expected from prior information, the anti-infective area being dependent on natural products and their structures. Although combinatorial chemistry techniques have succeeded as methods of optimizing structures and have been used very successfully in the optimization of many recently approved agents, we are able to identify only one de novo combinatorial compound approved as a drug in this 30-year time frame. We wish to draw the attention of readers to the rapidly evolving recognition that a significant number of natural product drugs/leads are actually produced by microbes and/or microbial interactions with the "host from whence it was isolated", and therefore we consider that this area of natural product research should be expanded significantly.
Angiogenesis, the process of blood vessel formation, is critical to tumour growth. The importance of angiogenesis in tumour development has lead to the development of anti-angiogenic strategies to inhibit tumour growth. In this study, polyphyllin D (PD), an active component in Chinese herb, Paris polyphylla, was evaluated for its potential anti-angiogenic effects.
The inhibitory effects of PD on three important processes involved in angiogenesis, i.e. proliferation, migration and differentiation were examined using human microvascular endothelial cell line HMEC-1 by MTT assay, scratch assay and tube formation assay, respectively. Using zebrafish embryos as an animal model of angiogenesis, the anti-angiogenic effect of PD was further verified in vivo.
PD suppressed the growth of HMEC-1 cells at 0.1-0.4 μM without toxic effects. At 0.3 μM and 0.4 μM, PD significantly inhibited endothelial cell migration and capillary tube formation. About 70% of the zebrafish embryos showed defects in intersegmental vessel formation upon treatment with PD at concentrations of 0.156 μM and 0.313 μM.
The anti-angiogenic effects of PD have been explored in the study which implied a potential therapeutic development of PD in cancer treatment.
In this study, we demonstrated that YM155, a novel survivin suppressant, induced both apoptosis, and autophagy that was shown by conversion of cytosolic-associated protein light chain 3 (LC3I) into autophagosome-associated form (LC3II) and a punctate fluorescence pattern of an ectopic GFP-LC3 protein. The lysosomal inhibitor chloroquine further accumulated YM155-induced LC3II, indicating an increase of autophagic flux. Ectopic expression of survivin significantly attenuated YM155-induced apoptosis and autophagy, whereas survivin siRNA induced autophagy. Furthermore, inhibition of either early or late events of autophagy attenuated YM155-induced apoptosis, demonstrating that induction of autophagy proceeds apoptosis. In conclusion, suppression of survivin by YM155 induces autophagy-dependent apoptosis, and YM155-induced autophagy plays a pro-apoptotic role thereby unveiling a novel mechanism of YM155 in prostate cancer cells.
Formosanin C is a pure compound isolated from Paris formosana Hayata (Liliaceae). The antitumor efficacy of formosanin C has been observed in cultured cells and animal systems. However, the molecular mechanisms of formosanin C remain unknown. The results of the present study indicate that formosanin C induced apoptosis of HT-29 cells characterized by exposure of phosphatidylserine, accumulation of cells at the sub-G(1) phase, fragmentation of DNA, and change of nuclear morphology in a time- and dose-related manner. The apoptotic signaling cascades may proceed via proteolytic activation of caspase-2, change of mitochondrial membrane potential (Deltapsi(m)), release of cytochrome c and second mitochondria-derived activator of caspase/direct IAP binding protein with low pI (Smac/DIABLO), activation of caspase-9 and -3, and cleavage of poly(ADP-ribose) polymerase (PARP). Increase in apoptosis-inducing factor and endonuclease G expressions in nuclei, and increase in Bax and Bak expressions and decrease in Bcl-X(L) expression on mitochondria were also observed in formosanin C-treated HT-29 cells. Attenuation of formosanin C-induced change of Deltapsi(m) by caspase-2 inhibitor (Z-VDVAC) implies that caspase-2 acts upstream of the mitochondria. Blockage of formosanin C-induced apoptotic process by using either permeability transition pore inhibitor (cyclosporine A) or caspase-9 inhibitor (Z-LEHD) demonstrates the necessity of mitochondria and caspase-9 in formosanin C-induced apoptosis of HT-29 cells. Taken together, the apoptotic mechanism of formosanin C in human colorectal cancer HT-29 cells involves activation of caspase-2 and the dysfunction of mitochondria.
Polygonatum cyrtonema lectin (PCL), a mannose-binding lectin, has been reported to induce cytotoxicity and apoptosis. Herein, we demonstrated that PCL-induced apoptosis and autophagy in A375 cells. The apoptotic mechanism was that PCL treatment regulated Bax, Bcl-xL and Bcl-2 proteins, leading to mitochondrial depolarization, cytochrome c release and caspase activation. Subsequently, we found that PCL treatment abrogated glutathione antioxidant system and induced mitochondria to generate ROS accumulation, resulting in p38-p53 activation. Moreover, we confirmed that the ROS-p38-p53 pathway was involved in PCL-induced autophagy. In conclusion, these results indicate that PCL induces apoptosis and autophagy via a mitochondrial-mediated ROS-p38-p53 pathway.
3-Methyladenine (5 mM) inhibits endogenous protein degradation in isolated rat hepatocytes by about 60%, while having no adverse effect on the degradation of an exogenous protein (asialofetuin), on protein synthesis, or on intracellular ATP levels. 3-Methyladenine appears to act specifically upon the autophagic/lysosomal pathway of degradation, as judged from its lack of effect in the presence of amino acids or a lysosomotropic amine (propylamine). The effect of the purine is not mediated by amino acids because the inhibition of protein degradation is accompanied by a significant depression of intracellular amino acid levels. The ability of 3-methyladenine to suppress the formation of electron microscopically visible autophagosomes suggests that it may be regarded as a specific inhibitor of autophagy.
Thioredoxin reductase (TrxR)-as part of a major thiol regulating system-allows redox metabolism to adjust to cellular requirements. Therefore, changes at the redox level reflect as a pars pro toto changes concerning the entire cell. Three different TrxR isoenzymes, TrxR1 as cytosolic, TrxR2 as mitochondrial, and TrxR3 as testis-specific thiol regulator are known. All three enzymes contain a reactive and solvent accessible selenocysteine residue which is located on a flexible C-terminal arm of the protein. This selenocysteine is essentially involved in the catalytic cycle of TrxR and thus represents an attractive binding site for inhibitors. Many tumor cells have elevated TrxR levels and TrxR has been shown to play a major role in drug resistance. Inhibition of TrxR and its related redox reactions may thus contribute to a successful single, combinatory or adjuvant cancer therapy. A great number of effective natural and synthetic TrxR inhibitors are now available possessing antitumor potential ranging from induction of oxidative stress to cell cycle arrest and apoptosis. This article summarizes the present knowledge on the potential of TrxR inhibitors and TrxR as anticancer drug target.
The intracellular redox state is a key determinant of cell fate, such as cell survival, proliferation, differentiation, and apoptosis. Redox imbalance is closely linked to a variety of human diseases, so that the intracellular redox condition should be tightly regulated. The redox state of the cell is a consequence of the precise balance between the levels of oxidizing and reducing equivalents, such as reactive oxygen species (ROS) and endogenous antioxidants. ROS are not only toxicants to the cell, but also second messengers in intracellular signal transduction, and control the action of several signaling pathways, including mitogen-activated protein (MAP) kinases. Apoptosis signal-regulating kinase 1 (ASK1) is a MAP kinase kinase kinase of the c-Jun N-terminal kinase (JNK) and p38 MAP kinase pathways, which is preferentially activated in response to various types of stress such as oxidative stress and plays pivotal roles in a wide variety of cellular responses. Recent studies have revealed that ASK1 is also required for innate immune response through ROS production. In this review, we focus on redox control of cell function by MAP kinase signaling, and provide the advanced mechanism of redox-regulated ASK1 activation and physiological roles of the ASK1-MAP kinase pathway in stress signaling.