Maspin inhibits MCF-7 cell invasion and proliferation by downregulating miR-21 and increasing the expression of its target genes

Maspin has been identified as a tumor suppressor gene in breast cancer, but the underlying regulatory mechanisms remain unclear. In the present study, maspin pcDNA was transfected into MCF-7 cells. microRNA (miR) microarray and reverse transcription-quantitative polymerase chain reaction was used for analysis; the results demonstrated that maspin may inhibit miR-10b, miR-21 and miR-451 expression in MCF-7 cells. In addition, maspin increased the expression of certain miR-21 target genes (phosphatase and tensin homolog, programmed cell death 4 and B-cell lymphoma-2), miR-10b target gene (Homeobox D10; HOXD10) and miR-451 target gene (multidrug resistance protein 1). Furthermore, the results of the present study revealed that decreased expression of miR-21 suppressed the invasion and proliferation of MCF-7 cells. Therefore, in the present study, it was hypothesized that as a tumor-suppressor gene, the potential molecular mechanism of maspin include down-regulating the expression of miR-21 and increasing the expression of specific miR-21 target genes.