Statins as adjuvants in the treatment of ovarian cancer: Controversy and misunderstanding

Circ_0001068 accelerates the development of ovarian cancer by promoting FXYD5 expression through inhibiting mir-149-5p activity

BACKGROUND

Ovarian cancer (OC) is one of the common malignancies of the female reproductive organs. Microarray analysis shows that circ_0001068 is upregulated in OC patients, however, its carcinogenic effect on OC development has not yet been revealed.

METHODS

In this study, qRT-PCR and western blotting were used to determine the expression of circ_0001068, microRNA-149-5p (miR-149-5p) and domain containing ion transport regulator 5 (FXYD5). Clone formation was used to assess cell proliferation, and transwell assays were performed to analyze cell migration and invasion. Dual-luciferase reporter and pull down assays were used to verify the binding relationship between circ_0001068 and miR-149-5p or FXYD5. Mouse xenograft tumor formation was performed to validate the role of circ_0001068 in vivo.

RESULTS

We found that the expression levels of circ_0001068 and FXYD5 were significantly increased in OC tissues and cell lines. Circ_0001068 knockdown significantly inhibited cell proliferation, migration, invasion, glycolysis, and glutamine metabolism. Circ_0001068 directly interacted with miR-149-5p, and the introduction of miR-149-5p mimics in OC cells partially reversed circ_0001068 knockdown-mediated effects. MiR-149-5p directly interacted with the 3'untranslated region (3'UTR) of FXYD5, and FXYD5 overexpression partially counteracted circ_0001068 knockdown-mediated effects in OC cells. Circ_0001068 knockdown inhibited xenograft tumor growth in vivo.

CONCLUSION

Our findings suggest that circ_0001068 promotes the malignant properties of OC cells by targeting the miR-149-5p/FXYD5 axis.

Why make it if you can take it: review on extracellular cholesterol uptake and its importance in breast and ovarian cancers

Cholesterol homeostasis is essential for healthy mammalian cells and dysregulation of cholesterol metabolism contributes to the pathogenesis of various diseases including cancer. Cancer cells are dependent on cholesterol. Malignant progression is associated with high cellular demand for cholesterol, and extracellular cholesterol uptake is often elevated in cancer cell to meet its metabolic needs. Tumors take up cholesterol from the blood stream through their vasculature. Breast cancer grows in, and ovarian cancer metastasizes into fatty tissue that provides them with an additional source of cholesterol. High levels of extracellular cholesterol are beneficial for tumors whose cancer cells master the uptake of extracellular cholesterol. In this review we concentrate on cholesterol uptake mechanisms, receptor-mediated endocytosis and macropinocytosis, and how these are utilized and manipulated by cancer cells to overcome their possible intrinsic or pharmacological limitations in cholesterol synthesis. We focus especially on the involvement of lysosomes in cholesterol uptake. Identifying the vulnerabilities of cholesterol metabolism and manipulating them could provide novel efficient therapeutic strategies for treatment of cancers that manifest dependency for extracellular cholesterol.