Hypoxia promotes the growth and metastasis of ovarian cancer cells by suppressing ferroptosis via upregulating SLC2A12.

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.

Paired box 8 facilitates the c-MYC related cell cycle progress in TP53-mutation uterine corpus endometrial carcinoma through interaction with DDX5.

As a molecular marker of the female reproductive system, Paired Box 8 is widely used in pathological diagnosis of gynecological tumors, but it is not clear whether its expression level is related to the development of uterine corpus endometrial carcinoma and molecular subtype classifications. Here, we show that PAX8 is up-regulated in TP53 mutation category of UCEC, which is result from the low methylation level of PAX8 in UCEC. We have identified that genes connected to ribosome, lysosome, ribosome biogenesis and cell cycle as PAX8 targets and demonstrate that modulation of the PAX8-DDX5 interaction influences c-MYC related cell cycle and cell growth. Our work defines DDX5 as a critical PAX8 co-factor, places the PAX8-DDX5 interaction in biological context, and highlights PAX8 as a key point for development of novel anti-MYC therapies in TP53-mutation UCEC.

HPV16 E6 promotes cell proliferation, migration, and invasion of human cervical cancer cells by elevating both EMT and stemness characteristics.

In most cases of cervical cancer, the high risk of the disease is caused by the human papilloma virus (HPV). Surgery or radiation usually benefits patients with early cervical cancer, while the metastatic one is uncurable and new therapeutic strategies and approaches are required. In this study, HPV16 E6 silence or overexpression were carried out to evaluate the possible mechanisms of HPV16 E6 function in cervical cancer cells with different HPV16 E6 expression background. HPV16 E6-positive cervical cancer cell Siha exerts significantly stronger cell invasion and migration potentials than the HPV16 E6-negative C33A cells. HPV16 E6 silence significantly weakened the potentials of cell invasion and migration, cell proliferation and stemness characteristic in Siha cells. Meanwhile, the overexpression of HPV16 E6 effectively promoted the cell proliferation and stemness characteristic in C33A cells. Our data also indicated a positive association between HPV16 E6 and the levels of epithelial to mesenchymal transition (EMT), and cell stemness. The ectopic expression of OCT4 could effectively reverse the inhibitory roles of HPV16 E6 silence on cell migration, invasion, and stemness in Siha cells. More interestingly, we found that HPV16 E6 might promote the OCT4 expression by impairing the direct binding of p53 on the promoter and activate its transcription. Taken together, our results indicated that HPV16 E6 could promoted the potential cell proliferation, migration, and invasion of human cervical cancer cells by modulating EMT and cell stemness. Our data provide a novel mechanism for how HPV16 E6 acts as a key risk factor for cervical cancer development and progression.

FoxM1 promotes the migration of ovarian cancer cell through KRT5 and KRT7.

Forkhead box M1(FoxM1) played an important role in the pathogenesis of ovarian cancer, but its downstream molecular network is mysterious. Here, we combined ChIP-seq with RNA-seq analysis and identified 687 FoxM1-binding regions and 182 genes regulated by FoxM1. The above data pointed out that KRT5 and KRT7 were downstream target genes of FoxM1. Next, we used qPCR and Western blot to verify that FoxM1 knockdown inhibited the expression levels of KRT5 and KRT7. We also demonstrated that FoxM1 regulated KRT5 and KRT7 genes expression through binding a consensus AP-2 cis element, and showed that KRT5 and KRT7 deficiency could prevent the migration but not proliferation of SK-OV-3 cells. Finally, tissue microarray results indicated that KRT5 and KRT7 were highly expressed in ovarian cancer and positively correlated with FoxM1 expression. TCGA database showed that high expression of KRT5 and KRT7 could significantly reduce the survival rate of patients with ovarian cancer. The above results clarify the specific downstream molecular network of FoxM1 to promote the pathogenesis of ovarian cancer, and provide a basis experiment for the judgment of ovarian cancer prognosis and the design of drug targets.