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The in vivo selection of highly metastatic (HM) OC cells (A) Schematic diagram of the establishment of HM cells. (B) Orthotopic transplantation of tissue blocks. The incision should be made at the lowest point in the depression area between the rib bow and the thigh near the spine on a left lateral position. Circle: White, spleen; Blue, kidney; Red, suitable area for incision. Arrow: Yellow, the lowest point in the side view; Blue, incision of ovary bursa; Green, tissue block; Red, suture of ovary bursa. (C) The procedures of in vivo selection for ES2-HM cells. After 3 rounds of in vivo selection, the HM cells, named ES2-HM, are gained from the omental metastatic tumor of passage 3 mice. Arrow: The omental tissue with the strongest luminescent signals is determined by ex vivo imaging and obtained for orthotopic inoculation in the mice of the next passage.
Source publication
Epithelial ovarian cancer (OC) is often diagnosed at an advanced stage with peritoneal metastasis, and preclinical models mimicking the natural course of OC peritoneal metastasis are essential to improve treatment. We implanted ES2 and ID8 cells in the ovaries of mice and obtained highly metastatic (HM) sublines from their omental metastases after...
Contexts in source publication
Context 1
... Therefore, tissue blocks of subcutaneous xenografts derived from luciferase-labeled ES2 cells were used for the establishment of orthotopic mouse models (Balb/c nude mice) at passage 1. In subsequent passages, the omental metastatic lesions of previous passages were transplanted into the ovarian bursa ( Figures 1A, 1B, and S1). Over three cycles of in vivo selection, tumor progression was gradually accelerated, and the survival of tumor-bearing mice was shortened. ...
Context 2
... three cycles of in vivo selection, tumor progression was gradually accelerated, and the survival of tumor-bearing mice was shortened. Passage 1 mice showed extensive peritoneal dissemination 17.00 G 1.7 days after transplantation and reached a humane endpoint due to obvious ascites formation 23.33 G 7.5 days after transplantation, while the average progression-free time and survival in passage 3 mice were less than 12 days and 16 days, respectively, indicating a significant increase in the metastatic ability of tumor cells ( Figures 1C and S2). Finally, the tumor cells were derived from the omental metastases of passage 3 mice and named ES2-HM. ...
Context 3
... inoculation was conducted on mice aged 5 weeks (3 mice per group). Briefly, tissue blocks (sized 1-2 mm 3 ) derived from subcutaneous tumors were inserted into the ovarian bursa of the mice (detailed procedures shown in Figure 1B). ...
Citations
... The OC cell Lines A2780, ES-2, SK-OV-3, and OVCAR-4 were purchased from the China Center for Type Culture Collection (Wuhan University). The highly metastatic ES-2 subline ES-2-HM was constructed in our laboratory [56]. Briefly, ES-2 cells were implanted in the ovary of nude mice, and ES-2-HM cells were isolated from omental metastases after three cycles of in vivo selection. ...
Background
Omental metastasis is the major cause of ovarian cancer recurrence and shortens patient survival, which can be largely attributed to the dynamic evolution of the fertile metastatic microenvironment driven by cancer cells. Previously, we found that adipose-derived mesenchymal stem cells (ADSCs) undergoing a phenotype shift toward cancer-associated fibroblasts (CAFs) participated in the orchestrated omental premetastatic niche for ovarian cancer. Here, we aim to elucidate the underlying mechanisms.
Methods
Small extracellular vesicles were isolated from ovarian cancer cell lines (ES-2 and its highly metastatic subline, ES-2-HM) and patient ascites using ultracentrifugation. Functional experiments, including Transwell and EdU assays, and molecular detection, including Western blot, immunofluorescence, and RT–qPCR, were performed to investigate the activation of ADSCs in vitro. High-throughput transcriptional sequencing and functional assays were employed to identify the crucial functional molecules inducing CAF-like activation of ADSCs and the downstream effector of miR-320a. The impact of extracellular vesicles and miR-320a-activated ADSCs on tumor growth and metastasis was assessed in subcutaneous and orthotopic ovarian cancer xenograft mouse models. The expression of miR-320a in human samples was evaluated using in situ hybridization staining.
Results
Primary human ADSCs cocultured with small extracellular vesicles, especially those derived from ES-2-HM, exhibited boosted migration, invasion, and proliferation capacities and elevated α-SMA and FAP levels. Tumor-derived small extracellular vesicles increased α-SMA-positive stromal cells, fostered omental metastasis, and shortened the survival of mice harboring orthotopic ovarian cancer xenografts. miR-320a was abundant in highly metastatic cell-derived extracellular vesicles, evoked dramatic CAF-like transition of ADSCs, targeted the 3′-untranslated region of integrin subunit alpha 7 and attenuated its expression. miR-320a overexpression in ovarian cancer was associated with omental metastasis and shorter survival. miR-320a-activated ADSCs facilitated tumor cell growth and omental metastasis. Depletion of integrin alpha 7 triggered CAF-like activation of ADSCs in vitro.
Conclusions
miR-320a in small extracellular vesicles secreted by tumor cells targets integrin subunit alpha 7 in ADSCs and drives CAF-like activation, which in turn facilitates omental metastasis of ovarian cancer.
Graphical Abstract
... The premetastatic niche is a tumor microenvironment previously formed thanks to exosomes. Exosomes are produced by the primary tumor and are the so-called "green light" for metastasis [22]. They create an optimal environment for the growth and progression of the tumor process. ...
Introduction. Ovarian cancer is an oncogynecological disease with high mortality. High mortality caused by this pathology is associated with diagnosis at the III–IV stage of the disease. This stage of the disease is characterized by metastasis and reflected in the 5-year survival rate, decreasing to 30.2 %. At the same time, when diagnosed at the I-II stage, this indicator is 92.6%. The aim of the work is bibliometric analysis and generalization of data from scientific sources on the study of ovarian cancer metastasis. Materials and methods. Information was searched on electronic resources of the Scopus, Web of Science, PubMed, and Google Scholar databases using the keywords "ovarian cancer" and "metastases." An online platform for monitoring and analyzing scientific sources was used for bibliometric analysis. We used several VOSviewer bibliometric network visualization system tools and SciVal (Scopus) modern citation requirements. Results. It has been established that metastasis of ovarian cancer can occur in several ways and depends on the conditions of the tumor microenvironment. The influence of E-cadherin, MMP-2, and transglutaminase-2 on metastasis processes was evaluated. Also, the role of cytokines in the invasiveness of the tumor process and metastasis was established. The results of bibliometric analysis of scientific sources showed that over the past 20 years, the number of publications on ovarian cancer metastasis has increased significantly, and the most widely given topic is studied in the USA and China. Conclusions. Metastasis of ovarian cancer can occur in several ways and depends on the conditions of the tumor microenvironment. It was found that among the analyzed 496 publications, the most relevant directions are molecular-biological and signaling pathways, which are described in many ways in scientific sources on ovarian cancer metastasis. The calcification of peritoneal metastases and their formation mechanism are currently not investigated, and there is no thorough explanation that may become a perspective for further research.
... HM cells can metastasize from the ovary to the omentum within 2 weeks. For complete details on the use and execution of this protocol, please refer to Ying et al. 1 ...
Preclinical models mimicking spontaneous omental metastasis from ovarian cancer (OC) can benefit the study of anti-metastatic therapies for OC patients. Here, we present a protocol to establish a highly metastatic (HM) mouse model with omental tropism by in vivo selection. We describe the processes of implanting OC cells in the ovaries of mice and obtaining HM sublines from their omental metastases. HM cells can metastasize from the ovary to the omentum within 2 weeks.
For complete details on the use and execution of this protocol, please refer to Ying et al.¹
Cancer‐associated fibroblasts (CAFs) represent a major cellular component of the tumor (pre‐)metastatic niche and play an essential role in omental dissemination of ovarian cancer. The omentum is rich in adipose, and adipose‐derived mesenchymal stem cells (ADSCs) have been identified as a source of CAFs. However, the molecular events driving the phenotype shift of ADSCs remain largely unexplored. In this research, we focus on integrins, transmembrane receptors that have been widely involved in cellular plasticity. We found that integrin α7 (ITGA7) was the only member of the integrin family that positively correlated with both overall survival and progression‐free survival in ovarian cancer through GEPIA2. The immunohistochemistry signal of ITGA7 was apparent in the tumor stroma, and a lower omental ITGA7 level was associated with metastasis. Primary ADSCs were isolated from the omentum of patients with ovarian cancer and identified by cellular morphology, biomarkers, and multilineage differentiation. The conditional medium of ovarian cancer cells induced ITGA7 expression decrease and phenotypic changes in ADSCs. Downregulation of ITGA7 in primary omental ADSCs led to decrease in stemness properties and emerge of characteristic morphology and biomarkers of CAFs. Moreover, the conditioned medium of ADSCs with ITGA7 depletion exhibited enhanced abilities to improve the migration and invasion of ovarian cancer cells in vitro. Overall, these findings indicate that loss of ITGA7 may induce the differentiation of ADSCs to CAFs that contribute to a tumor‐supportive niche.
