Inhibition of breast cancer metastasis by using miR-31-mimic in cancer stem cell rich MDA-MB231 cell line

Metastasis associated miRNA (metastamiR) opened a new field of anti-metastatic therapy which have a great potential of treatment for the most lethal aspect of cancer، metastasis. The pleiotropic nature of gene regulation exhibited by certain miRNAs that showed that miRNAs might be endowed with a capacity to function as crucial modulators of tumor metastasis. MiR-31 is a pleiotropic anti-metastatic miRNA whose expression decreased significantly in metastatic breast cancer cells. MiR-31 has multiple roles in metastasis cascade. Therefore، using the miR-31-restoration based therapy could be an efficient anti-metastatic strategy for cancer therapy. This research was performed from May 2014 to October 2015 in Tarbiat Modares University in Tehran، Iran. The double-strand oligo of mature miR-31 was cloned into pcDNA 6. 2gw/EmGFP according to the manufacturer instruction. The MDA-MB231، MCF-7 breast cancer cell lines were cultured and their miRNAs have been extracted. The expression of miR-31 has been quantified by Real time-PCR be-fore transfection of construct contained miR-31 into two cell lines and in normal breast cells. Then the constructs contain miR-31 have been transfected in to two cell lines. The expression of miR-31 has been quantified after 48 hours. Scratch and invasion as-say have been carried out for assessing the level of migration and invasion. The result of Real time-PCR before transfection of constructs contained miR-31 have been shown 4 fold and more than 100 fold reduction in expression of miR-31 in MCF-7 and MDA-MB231 respectively in comparison to miR-31 expression in nor-mal breast cells، but after transfection of miR-31 construct to MDA-MB231 the quan-tification of expression showed the significant increase in mir-31 expression and 20 fold reduction in invasive and 10 fold reduction in migratory characteristics of MDA-MB231 in comparison to MCF-7. Metastasis associated miRNA have been represented a promising candi-dates in the field of anti-metastatic therapy and miR-31 as a powerful member of this family can function very effectively in order to inhibit the metastasis and introduce the new possibility of metastasis inhibition.