Mingmei Li,Li Li,Xiaoxiao Cheng,Longyu Li,Kaijia Tu
Background Ovarian cancer has been a worldwide health burden for women and its progression is highly hypoxia-independent. Here, we investigated the exact mechanisms by which hypoxia contributes to the malignant progression of ovarian cancer. Method MTT, transwell, colony formation, and scratch wound healing assays were carried out for cellular functions. The underlying mechanism by which hypoxia functions was explored by RNA-seq, enrichment analysis, western blotting, qRT-PCR, flow cytometry, ChIP, luciferase reporter, and ELISA. Finally, animal experiments including the xenograft model and tumor metastasis model were constructed to validate the role of SLC2A12 in vivo . Results Hypoxia treatment promoted the cell proliferation, mobility, and colony growth abilities of the two ovarian cancer cell lines HO-8910 and A2780. RNA-seq and enrichment analysis showed that SLC2A12 was hyper-expressed under hypoxia condition and it may be related to glutathione and lipid metabolism. Besides, the expression of SLC2A12 was negatively correlated with overall survival. Hypoxia suppressed ferroptosis by SLC2A12 because silencing SLC2A12 declined the cell viability of HO-8910 and A2780 cells under hypoxia conditions, while the ferroptosis inhibitor ferrostatin-1 (Fer-1) breached that result and upregulated the expression of glutathione peroxidase 4 (GPX4). Moreover, hypoxia increased the expression of hypoxia inducible factor 1 A (HIF-1A), and the accumulated HIF-1A binds to hypoxia inducible factor 1 B (HIF1B) to form HIF-1 complex, then promoted the binding of hypoxic response elements (HRE) to SLC2A12 promoter by HIF-1/HRE signal. Subsequently, SLC2A12 regulated glutathione metabolism and in turn inhibited ferroptosis. The animal experiments indicated that silencing SLC2A12 could significantly inhibit tumor growth and metastasis in vivo . Conclusion Hypoxia promoted ovarian cancer progression by upregulating SLC2A12 and then regulating glutathione metabolism to inhibit ferroptosis.
This study aimed to examine hypoxia-induced phenotypic alterations in ovarian cancer and to elucidate the molecular mechanisms mediated by long non-coding RNAs (lncRNAs). Transwell assay was used to assess migration and invasion, and methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay was used to assess proliferation. Western blot analysis was conducted to evaluate the expression of factors associated with epithelial–mesenchymal transition (EMT). RNA sequencing was carried out to identify potential targets, and dual-luciferase and biotin-labeled microRNA (miRNA) pull-down assays were performed to identify interactions between these targets. Gain- and loss-of-function experiments were conducted to validate their effects. Hypoxia promoted the migration, invasion, and EMT of HO8910 and A2780 cells. Under hypoxic conditions, the expression of lncRNA-aspartyl-transfer RNA synthetase antisense RNA 1 (lnc- DARS-AS1 ) was significantly increased, and this upregulation exerted a proliferative effect on ovarian cancer cells. Furthermore, lnc- DARS-AS1 promoted solute carrier family 2 member 12 (SLC2A12) expression, accelerating ovarian cancer progression. Luciferase, biotin-labeled miRNA pull-down, and cellular function assays confirmed that lnc- DARS-AS1 binds to miR-378a-5p to enhance SLC2A12 levels. The expression levels of SLC2A12 were determined in samples from patients with ovarian cancer, and they showed a positive correlation with cancer progression. This research established that the lnc- DARS-AS1 /miR-378a-5p/SLC2A12 axis is involved in ovarian cancer progression under hypoxic conditions, providing new perspectives on the treatment and management of ovarian cancer.
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