Unveiling miRNA30b's Role in Suppressing ADAM12 to Combat Triple-Negative Breast Cancer

Background: Triple-negative breast cancer, a subtype of breast cancer, is characterized by a poor prognosis. Recent studies have shown that miRNA30b acts as an oncogene and is vital for the proliferation of malignancies across various systems. This study aimed to elucidate the impact of miRNA30b on the proliferation, migration, and invasion capabilities of breast cancer cells in vitro. Methods: Triple-negative breast cancer cell lines MDA-MB-231 were transiently transfected with miRNA30b inhibitor, mimic, or the negative control by Lipofectamine 2000. Successful transfection was confirmed by quantitative real-time polymerase chain reaction (qRT-PCR). Functional assays, including CCK8, clone formation, scratch, and transwell assays, were conducted to evaluate the proliferation, invasion, and migration ability of MDA-MB-231 cells in each group. The target protein of miRNA30b was determined using an online prediction data website, and the dual-luciferase assay confirmed whether there was a binding site between miRNA30b and ADAM12. The effect was further verified by Western blot analysis. Results: MDA-MB-231 cells were transfected with miRNA30b inhibitor, mimic, and negative control. miRNA30b expression was downregulated in the cells. Relative to the negative control group, miRNA30b expression significantly increased in the mimic group and decreased in the miRNA30b inhibitor group, with the differences being statistically significant. The miRNA30b mimic group exhibited a significant increase in miRNA30b expression and a corresponding promotion of cell proliferation, colony formation, and migration. Conversely, the miRNA30b inhibitor group displayed significantly reduced miRNA30b expression and suppressed cell proliferation, colony formation, and migration abilities compared to the negative control cells. Bioinformatics software predicted ADAM12 as a potential target of miRNA30b. Dual-luciferase assays confirmed the presence of a binding site between miRNA30b and ADAM12. Western blot analysis revealed that overexpression of miRNA30b downregulated ADAM12 expression in MDA-MB-231 cells. Conclusions: miRNA30b could promote proliferation, migration, and invasion of TNBC cell lines MDA-MB-231. The effect of miRNA30b on triple-negative breast cancer would be achieved partly at least through inhibiting the expression of ADAM12.