Objective: To investigate the effect of microRNA-101 (miR-101) on the proliferation and migration of breast cancer cells and its possible mechanism.
Methods: The expressions of miR-101 and DNA methyltransferase 3a (DNMT3a) in breast cancer tissues, corresponding normal breast tissues, breast cancer cells and normal breast cells were detected by real-time quantitative PCR. The lentiviral vectors containing miR-101 and shRNA-DNMT3a sequences were transfected into MDA-MB-231 cells to regulate the expressions of miR-101 and DNMT3a. The expressions of DNMT3a and E-cadherin were determined by Western blotting. The proliferation and migration abilities of MDA-MB-231 cells were evaluated by MTT assay and wound healing assay, respectively.
Results: Breast cancer tissues and breast cancer cell lines (MCF-7, MDA-MB-231, MDA-MB-361, HCC70) showed lower miR-101 expression and higher DNMT3a expression than the adjacent normal breast tissues and normal breast cell line. The overexpression of miR-101 resulted in downregulation of DNMT3a and restoration of E-cadherin. Besides, knockdown of DNMT3a by shRNA increased E-cadherin expression. MTT assay and would healing assay showed that miR-101 overexpression significantly inhibited the proliferation and migration abilities of MDA-MB-231 cells.
Conclusion: miR-101 may inhibit MDA-MB-231 cell proliferation and migration by repressing DNMT3a expression and up-regulating E-cadherin expression.