MicroRNAs (miRNAs) are a class of small non-coding RNAs with a length of 21–25
nucleotides and play an essential role in the regulation of cancer initiation,
development and progression. Breast cancer (BC) is the most commonly detected
malignancy in women and one of the leading causes of death worldwide. In this
study, the effects of transfection of microRNA-451a-5p and miR-34a-5p (tumor
suppressors), individually and in combination on apoptosis, proliferation and
migration of breast cancer cells in vitro were investigated. For this study, malignant
breast cancer cells (MDA-MB-231) were transfected with the miR-451a-5p and miR34a-5p mimics. Subsequently cytotoxicity, apoptosis, proliferation, migration protein
and gene expression of caspase-3, caspase-8, MMP9, ROCK, vimentin and c-Myc of
the cancer cells were analyzed by MTT, flow cytometry, q-RT-PCR (expression
level of caspase-3, caspase-8, MMP9, ROCK, vimentin and c-Myc genes), wound
healing and Western blot assays. The results showed that miR-34a-5p and miR-451a5p could additionally induce apoptosis and cell cycle arrest in the sub-G1phase,
suppress proliferation and migration in breast cancer cells, and also decrease the
expression of β- catenin and ERK/P-ERK proteins . The present data document that
restoration of the tumor suppressor miR-451/miR-34 strongly induces programmed
cell death in vitro and apparently inhibits cell proliferation and migration in human
breast cancer cells. In summary, miR-451a and miR-34a play an important role in
breast cancer cell proliferation and migration via the Wnt/β-catenin and ERK/P-ERK
signaling pathways. Therefore, the simultaneous restoration of the presented tumor
suppressor miRNAs can be proposed as a valuable and potential therapeutic strategy
in the treatment of breast cancer. However, further studies should be useful.