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Effects of specific fatty acids on sphinganine ± GT-11-induced dihydroceramides and cytotoxicity. A, B) Effects on dihydroceramides. CCRF-CEM cells were treated with (A) sphinganine (1 µM), or (B) sphinganine (1 µM) + GT-11 (0.5 µM), and supplemented with the indicated fatty acids (5 µM) for six hours, followed by sphingolipid assay. To evaluate the effects resulting from addition of each fatty acid, data for (A) and (B) were normalized either to cells that received sphinganine-only with no fatty acid supplementation (A), or to sphinganine + GT-11 without fatty acid (B), and plotted as fold change (Z-axis). Fatty acids are identified by x:y, where x is the number of carbons and y is the number of double bonds in the fatty acid chain (Y-axis). Significant (P ≤ 0.05) differences from sphinganine-only are indicated by asterisks (*). C) Effects on cytotoxicity. CCRF-CEM cells were treated with sphinganine-only (0-4 µM), or sphinganine (0-4 µM) + GT-11 (0.5 µM), supplemented with the indicated fatty acids (5 µM). Cytotoxicity assayed by DIMSCAN cytotoxicity assay at +48 hours. Data were normalized to control and plotted as survival fraction (Y-axis). Error bar, SEM. Data, grouped by sphinganine dose, were analyzed by one-way ANOVA. doi: 10.1371/journal.pone.0074768.g003
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We previously reported that fenretinide (4-HPR) was cytotoxic to acute lymphoblastic leukemia (ALL) cell lines in vitro in association with increased levels of de novo synthesized dihydroceramides, the immediate precursors of ceramides. However, the cytotoxic potentials of native dihydroceramides have not been defined. Therefore, we determined the...
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Sphingosine-1 phosphate (S1P) is a bioactive lipid that mediates diverse cellular responses. Signaling of S1P is carried out by a family of G-protein coupled receptors (GPCRs), which show differential expression patterns depending on tissue and cell types. Activation of S1P receptors induces signaling pathway, which can subsequently lead to physiol...
Citations
... • GT-11: this is a cyclopropene Cer molecule, where the C4-C5 double bond of Cer is replaced by a cyclopropene unit. GT-11 and its analogues act as DES1 inhibitors and have been studied mainly in cancer models, where they increase autophagy and apoptosis and inhibit tumor growth in mice models [101][102][103]. Interestingly, GT-11 is also able to inhibit flavivirus infection (e.g., West Nile virus) in a dose-dependent manner through DES inhibition [104]. ...
Ceramides and other related sphingolipids, important cellular components linked to metabolic homeostasis and cardiometabolic diseases, have been found to be involved in different steps of the SARS-CoV-2 life cycle. Hence, changes in their physiological levels are identified as predictors of COVID-19 severity and prognosis, as well as potential therapeutic targets. In this review, an overview of the SARS-CoV-2 life cycle is given, followed by a description of the sphingolipid metabolism and its role in viral infection, with a particular focus on those steps required to finalize the viral life cycle. Furthermore, the use and development of pharmaceutical strategies to target sphingolipids to prevent and treat severe and long-term symptoms of infectious diseases, particularly COVID-19, are reviewed herein. Finally, research perspectives and current challenges in this research field are highlighted. Although many aspects of sphingolipid metabolism are not fully known, this review aims to highlight how the discovery and use of molecules targeting sphingolipids with reliable and selective properties may offer new therapeutic alternatives to infectious and other diseases, including COVID-19.
... As ceramide has been studied for its apoptotic property, in most of these studies, dhCer has been considered as a precursor to ceramide [107,111,112]. Although some studies have focused on dhCer's potential role in cancer cell autophagy, [113][114][115]in cancer induced bone pain [116], and cell cytotoxicity [117]. The fluctuation in the dhCer and ceramide levels in cancer cells seem to differ according to the site of origin of the cancer. ...
: Molecular targeting strategies have been used for years to control cancer progression and are often based on targeting various enzymes involved in metabolic pathways. Keeping that in mind, it is essential to know the role of each enzyme in a particular metabolic pathway. In this review, we are providing in-depth knowledge of various enzymes such as ceramidase, sphingosine kinase, sphingomyelin synthase, dihydroceramide desaturase, and ceramide synthase, which are associated with multiple types of cancer that depend on ceramide metabolism. Focus has also been given to discussing physicochemical properties of well-studied inhibitors of natural products origin and their related structures for these enzymes. Targeting ceramide metabolism exhibited promise in mono and combination therapies at preclinical stages to prevent cancer progression and paved the way for the significance of sphingolipid metabolism in cancer treatments. Targeting ceramide metabolizing enzymes will help the medicinal chemist to design potent and selective small molecules for treating cancer progression at various levels.
... On the other side, carnosine has been shown to play a protective role against the harmful effects of d18:0/22:0 dihydroceramide in the skin. Several forms of DhCer (C22:0 and C24:0) ( Figure 5, Table S1) induced cytotoxicity through a caspase-independent mechanism, mixed cell death with increased autophagy [33]. The role of DhCer as inducers of autophagy has been further confirmed by others in several cellular models [34,35]. ...
The lipid profile of skin is fundamental in the maintenance of the protective barrier against the external environment. Signaling and constitutive lipids of this large organ are involved in inflammation, metabolism, aging, and wound healing, such as phospholipids, triglycerides, FFA, and sphingomyelin. Skin exposure to ultraviolet (UV) radiation results in a photoaging process that is an accelerated form of aging. UV-A radiation deeply penetrates the dermis and promotes damage to DNA, lipids, and proteins by increasing the generation of reactive oxygen species (ROS). Carnosine, an endogenous β-alanyl-L-histidine dipeptide, demonstrated antioxidant properties that prevent photoaging and modification of skin protein profiling, making carnosine a compelling ingredient to consider for use in dermatology. The aim of this research was to investigate the modification of skin lipidome after UV-A treatment in presence or not of topic administration of carnosine. Quantitative analyses based on high-resolution mass spectrometry of nude mice skin-extracted lipids resulted in several modifications of barrier composition after UV-A radiation, with or without carnosine treatment. In total, 328 out of 683 molecules showed significant alteration—262 after UV-A radiation and 126 after UV-A and carnosine treatment versus controls. Importantly, the increased oxidized TGs after UV-A radiation, responsible of dermis photoaging, were completely reverted by carnosine application to prevent the UV-A damage. Network analyses also showed that the production of ROS and the calcium and TNF signaling were modulated by UV-A and carnosine. In conclusion, lipidome analyses attested the carnosine activity to prevent the UV-A damage, reducing the lipid oxidation, the inflammation, and the dysregulation of lipid skin barrier.
... Previous studies have suggested that dihydroceramides and ceramides might have distinct cellular functions 44,45 , and given that Degs1 silencing, in contrast to that of other upstream enzymes, did not boost myoblast differentiation, we examined whether Degs1 inhibition could not only inhibit myogenesis, but even abrogate the Sptlc1 deficiency-induced accelerated myotube formation. As poor aqueous solubility makes exogenous delivery of physiological long-chain sphingolipids difficult 46 , we administered GT-11 and sphinganine to myoblasts to load them with dihydroceramides according to a previously described method 47 (Fig. 7a). GT-11 was added to pharmacologically inhibit DEGS1 and sphinganine to ensure substrate availability for dihydroceramide formation in Sptlc1-deficient myoblasts. ...
Age-related muscle dysfunction and sarcopenia are major causes of physical incapacitation in older adults and currently lack viable treatment strategies. Here we find that sphingolipids accumulate in mouse skeletal muscle upon aging and that both genetic and pharmacological inhibition of sphingolipid synthesis prevent age-related decline in muscle mass while enhancing strength and exercise capacity. Inhibition of sphingolipid synthesis confers increased myogenic potential and promotes protein synthesis. Within the sphingolipid pathway, we show that accumulation of dihydroceramides is the culprit disturbing myofibrillar homeostasis. The relevance of sphingolipid pathways in human aging is demonstrated in two cohorts, the UK Biobank and Helsinki Birth Cohort Study in which gene expression-reducing variants of SPTLC1 and DEGS1 are associated with improved and reduced fitness of older individuals, respectively. These findings identify sphingolipid synthesis inhibition as an attractive therapeutic strategy for age-related sarcopenia and co-occurring pathologies.
... In connection with fenretinide's function as a DES1 inhibitor, the cytotoxic function of dihydroceramide (supposedly accumulating when DES1 is inhibited) has also been directly explored. Induction of de novo dihydroceramide synthesis via treatment with dihydrosphingosine, fatty acids, or GT-11 (another DES1 inhibitor) induced accumulation of C22:0-and C24:0-dihydroceramide, associated with cytotoxicity in MOLT-4, CCRF-CEM, COG-LL-317h, and COG-LL-332h ALL cell lines [238]. This finding points to dihydroceramide as a contributing factor in fenretinide's cytotoxicity in ALL cells. ...
... Indeed, a clinical trial testing ABC294640 in DLBCL (NCT02229981) was initiated, but later withdrawn due to a lack of recruitment (Table 1). [141] AML [141] LGL Leukemia [295] MP-A08 [115] AML [145] Safingol [347] Multiple Terminated: drug supply GT-11 [357] ALL [238] AC N-oleoylethanolamine [358] LGL Leukemia [294] SACLAC [156] AML [156] LCL204 [359] AML [113,159] aSMase ...
Dysregulation of sphingolipid metabolism plays a complex role in hematological malignancies, beginning with the first historical link between sphingolipids and apoptosis discovered in HL-60 leukemic cells. Numerous manuscripts have reviewed the field including the early discoveries that jumpstarted the studies. Many studies discussed here support a role for sphingolipids, such as ceramide, in combinatorial therapeutic regimens to enhance anti-leukemic effects and reduce resistance to standard therapies. Additionally, inhibitors of specific nodes of the sphingolipid pathway, such as sphingosine kinase inhibitors, significantly reduce leukemic cell survival in various types of leukemias. Acid ceramidase inhibitors have also shown promising results in acute myeloid leukemia. As the field moves rapidly, here we aim to expand the body of literature discussed in previously published reviews by focusing on advances reported in the latter part of the last decade.
... The inhibition of autophagy could thus constitute an antitumor mechanism against T-ALL, although it largely depends on the drug used. An example of this is the specific case of dihydroceramides C22:0 and C24:0, in which, although autophagy occurred when treating T-ALL cell lines, autophagic inhibition with 3-MA had no effect on cytotoxicity [129]. ...
... Human pre-B acute lymphocytic leukemic cell lines and fludarabine-resistant cells [105] Venetoclax Activation CLL cell lines [106] Flavopiridol Activation CLL cell lines [106] Cyclophosphamide + flavopiridol + rituximab Activation CLL cell lines [108] Dasatinib Activation CLL cell lines [112] 3-MA and CQ (Vorinostat) Inhibition Primary CLL cells [115] ALL Resistance to Glucocorticoids Inhibition B-ALL cell lines [120] Dexamethasone and MEK inhibitor Activation B-ALL cell lines [122] BTZ (Resistance) Inhibition B-ALL cell lines [124] L-Asparaginase Inhibition B-ALL cell lines [125] 20(S)-Ginsenoside Rh2 Inhibition B-ALL cell lines [126] Thymosaponin A-III Activation T-ALL cell lines [127] NVP-BKM120 Activation T-ALL cell lines [128] BTZ + Obotoclax Inhibition T-ALL cell lines [129] Quinacrine ...
Autophagy is a highly conserved metabolic pathway by which the intracellular unwanted materials, such as unfolded proteins or damaged organelles, are digested. It is activated in response to conditions of oxidative stress or starvation, and it is essential for the maintenance of cellular homeostasis and other vital functions, such as differentiation, cell death and cell cycle. Therefore, autophagy plays an important role in the initiation and progression of tumors, including hematological malignancies, where damaged autophagy during hematopoiesis can cause malignant transformation and increase cell proliferation. Over the last decade, the importance of autophagy in the response to standard pharmacological treatment of hematological tumors has been observed, revealing completely opposite roles depending on the tumor type and tumor stage. Thus, autophagy can promote tumor survival by attenuating cellular damage caused by drugs and/or stabilizing oncogenic proteins, but it can also have an antitumoral effect due to autophagic cell death. Therefore, autophagy-based strategies must depend on the context to create specific and safe combination therapies that could contribute to improve clinical outcomes. In this review, we describe the process of autophagy, its role on hematopoiesis and we highlight recent research investigating its role as potential therapeutic target in hematological malignancies and the findings suggesting that genetic variants within autophagy-related genes modulate the risk of developing hemopathies as well as patient survival.
... Although the DES1 inhibitors used here, namely 4HPR and SKi-II, are known to affect other targets, our conclusions are strongly supported by genetic loss of function experiments as well as gain of function approaches showing that DES1 is sufficient to drive AIS and enhance in vitro tumorigenicity. Of note, although effects of DES1 inhibitors on cell death and proliferation have been reported, [66][67][68] biological consequences of increased DES1 activity and/or expression are less well studied. Furthermore, our studies offer important context as to when DES1 inhibitors could be particularly effective, that is, in the metastatic setting where AIS is a key biology. ...
... An outstanding question relates to the mechanism by which DES1 promotes AIS and there are a couple of possibilities. Prior studies have shown that loss of DES1 activity can lead to activation of apoptosis, [66][67][68] autophagy, 46,67 and ER stress pathways. 69 Our studies here suggest that DES1 is not impacting classical anoikis pathways, as DES1 loss did not induce PARP cleavage or increase caspase activity. ...
... An outstanding question relates to the mechanism by which DES1 promotes AIS and there are a couple of possibilities. Prior studies have shown that loss of DES1 activity can lead to activation of apoptosis, [66][67][68] autophagy, 46,67 and ER stress pathways. 69 Our studies here suggest that DES1 is not impacting classical anoikis pathways, as DES1 loss did not induce PARP cleavage or increase caspase activity. ...
Oncogenic reprogramming of cellular metabolism is a hallmark of many cancers, but our mechanistic understanding of how such dysregulation is linked to tumor behavior remains poor. In this study, we have identified dihydroceramide desaturase (DES1)—which catalyzes the last step in de novo sphingolipid synthesis—as necessary for the acquisition of anchorage‐independent survival (AIS), a key cancer enabling biology, and establish DES1 as a downstream effector of HER2‐driven glucose uptake and metabolism. We further show that DES1 is sufficient to drive AIS and in vitro tumorigenicity and that increased DES1 levels—found in a third of HER2+ breast cancers—are associated with worse survival outcomes. Taken together, our findings reveal a novel pro‐tumor role for DES1 as a transducer of HER2‐driven glucose metabolic signals and provide evidence that targeting DES1 is an effective approach for overcoming AIS. Results further suggest that DES1 may have utility as a biomarker of aggressive and metastasis‐prone HER2+ breast cancer.
... However, its prolonged presence induces a concomitant increase in Cer levels, attributed to the activity of sphingomyelinase, which coincides with the promotion of cell death (18). A specificity of the acyl chain length of DhCer was revealed by a study showing that only the C22:0 and C24:0 DhCer were associated with increased autophagy and caspase-independent cell death of T cell acute lymphoblastic leukemia (ALL) cell lines (19). Furthermore, the importance of the membrane composition in DhCer in defining cellular behavior was highlighted when in glioma cells treatment with D 9 -tetrahydrocannabinol (THC) or DES1 inhibition led to an increase in the DhCer/Cer ratio composition of the ER membrane and induced ER stress. ...
Dihydroceramides are a type of sphingolipids that for a long time were regarded as biologically inactive. They are metabolic intermediates of the de novo sphingolipid synthesis pathway, and are converted into ceramides with the addition of a double bond. Ceramides are abundant in tissues and have well-established biological functions. On the contrary, dihydroceramides are less prevalent and despite their hitherto characterization as inert lipids, studies of the last decade begun to unravel their implication in various biological processes distinct from those involving ceramides. These processes include cellular stress responses and autophagy, cell growth, pro-death or pro-survival pathways, hypoxia and immune responses. In addition, their plasma concentration has been related to metabolic diseases and shown as a long-term predictor of type 2 diabetes onset. They are thus important players and potential biomarkers in pathologies ranging from diabetes to cancer and neurodegenerative diseases. The purpose of this mini-review is to highlight the emergence of dihydroceramides as a new class of bioactive sphingolipids by reporting recent advances on their biological characterization and pathological implications, focusing on cancer and metabolic diseases.
... Des1 is the target of the synthetic retinoid chemotherapeutic, fenretinide (4-hydroxyphenyl retinamide (4-HPR)) [365][366][367]. 4-HPR also increases activity of SPT, leading to the accumulation of cytotoxic dhCer [14,368,369]. In HEK293 cells, 4-HPR induced polyubiqutinylation of Des1, increasing enzymatic activity but targeting it for degradation, making Des1 activity dependent upon the rate of degradation induced by polyUb [310,370]. ...
Intensive research in the field of sphingolipids has revealed diverse roles in cell biological responses and human health and disease. This immense molecular family is primarily represented by the bioactive molecules ceramide, sphingosine, and sphingosine 1-phosphate (S1P). The flux of sphingolipid metabolism at both the subcellular and extracellular levels provides multiple opportunities for pharmacological intervention. The caveat is that perturbation of any single node of this highly regulated flux may have effects that propagate throughout the metabolic network in a dramatic and sometimes unexpected manner. Beginning with S1P, the receptors for which have thus far been the most clinically tractable pharmacological targets, this review will describe recent advances in therapeutic modulators targeting sphingolipids, their chaperones, transporters, and metabolic enzymes.
... Previous reports showed that fenretinide-mediated cytotoxicity is associated with dysregulation of lipid metabolism. Specifically, fenretinide is able to increase the intracellular levels of dihydroceramides species by targeting the dihydroceramide desaturase [16,29,38,51]. Liquid chromatography-mass spectrometry (LC-MS), showed that Bio-nFeR treatment induced a marked increase of dihydroceramide and dihydrosphingolipids (glucosyldihydroceramide) species (Fig. 5c and Additional file 1: Figure S3). ...
Background:
An increasing number of anticancer agents has been proposed in recent years with the attempt to overcome treatment-resistant cancer cells and particularly cancer stem cells (CSC), the major culprits for tumour resistance and recurrence. However, a huge obstacle to treatment success is the ineffective delivery of drugs within the tumour environment due to limited solubility, short circulation time or inconsistent stability of compounds that, together with concomitant dose-limiting systemic toxicity, contribute to hamper the achievement of therapeutic drug concentrations. The synthetic retinoid Fenretinide (4-hydroxy (phenyl)retinamide; 4-HPR) formerly emerged as a promising anticancer agent based on pre-clinical and clinical studies. However, a major limitation of fenretinide is traditionally represented by its poor aqueous solubility/bioavailability due to its hydrophobic nature, that undermined the clinical success of previous clinical trials.
Methods:
Here, we developed a novel nano-micellar fenretinide formulation called bionanofenretinide (Bio-nFeR), based on drug encapsulation in an ion-pair stabilized lipid matrix, with the aim to raise fenretinide bioavailability and antitumour efficacy.
Results:
Bio-nFeR displayed marked antitumour activity against lung, colon and melanoma CSC both in vitro and in tumour xenografts, in absence of mice toxicity. Bio-nFeR is suitable for oral administration, reaching therapeutic concentrations within tumours and an unprecedented therapeutic activity in vivo as single agent.
Conclusion:
Altogether, our results indicate Bio-nFeR as a novel anticancer agent with low toxicity and high activity against tumourigenic cells, potentially useful for the treatment of solid tumours of multiple origin.
