[Overexpression of miR-183-5p enhances malignant phenotype and inhibits ferroptosis of triple-negative breast cancer cells by negatively regulating KLHL24].

OBJECTIVES

To investigate the effects of miR-183-5p overexpression on proliferation, invasion, migration, and ferroptosis of triple-negative breast cancer (TNBC) cells and the role of Kelch-like protein 24 (KLHL24) in mediating these effects.

METHODS

Bioinformatics analyses were conducted to screen differentially expressed genes in breast cancer (BRCA) and predict the target gene of miR-183-5p. RT-qPCR was used to verify miR-183-5p expression in normal breast epithelial and TNBC cell lines. Dual-luciferase reporter assay was performed to confirm direct binding of miR-183-5p to 3'-UTR of KLHL24. Western blotting was used to detect KLHL24 expression in different TNBC cells after transfection with miR-183-5p-overexpressing plasmids. MDA-MB-231 cells were co-transfected with NC-miR and NC-KLHL24, oe-miR-183-5p and NC-KLHL24, NC-miR and oe-KLHL24, or oe-miR-183-5p and oe-KLHL24 plasmids, and the changes in cell proliferation, migration and invasion were examined using EdU, Transwell, and wound healing assays. Western blotting was used to detect the changes in expressions of ferroptosis-related proteins (GPX4, SLC7A11, and Nrf2), and ROS, LPO, MDA, and GSH levels in the transfected cells were determined.

RESULTS

The expression of miR-183-5p was significantly elevated in BRCA tissues and TNBC cell lines, and MDA-MB-231 cells showed the highest miR-183-5p expression. Dual-luciferase reporter assay confirmed the direct binding of miR-183-5p to 3'-UTR of KLHL24. Overexpression of miR-183-5p significantly downregulated KLHL24 expression. In TNBC cells, miR-183-5p overexpression obviously promoted cell proliferation, invasion, and migration, upregulated the expressions of GPX4, SLC7A11 and Nrf2, reduced the levels of ROS, LPO and MDA, and increased the level of GSH (P<0.0001); these effects were significantly reversed by co-transfection of the cells with KLHL24-overexpressing plasmids.

CONCLUSIONS

Overexpression of miR-183-5p enhances TNBC cell proliferation, invasion, migration and inhibits ferroptosis by negatively regulating KLHL24.