Alteration of ERalpha expression and tumor invasion by RNA interference against metastasis associated-1 gene in human breast cancer cells

Abstract

To investigate the inhibitory effect on MTA1 gene by MTA1 short hairpin RNA (shRNA), downstream regulation of expression of ERa and invasion of human breast cancer cells. Recombinant plasmid pGenesil-1/MTA1 was constructed and transfected into human breast cancer cell lines MDA-MB-231 and MCF-7. Fluorescence microscopy was used to evaluate the efficacy of transfection. The transcription expression of MTA1 and MMP-9 gene were determined by reverse transcription-polymerase chain reaction (RT-PCR), the protein expression of ERalpha and MMP-9 were determined by immunohistochemical and western blot. The invasion ability was evaluated by Boyden chamber invasive assay. Recombinant plasmid pGenesil-1/MTA1 was constructed and transfected into MDA-MB-231 (82.5%) and MCF-7 (78.2%) successfully. After the transfection, MTA1 mRNA was suppressed in both cell lines (80.2% and 58.7%). The expression of ERalpha protein became positive in transfected MDA-MB-231 cell, and the expression of MMP-9 mRNA were down-regulated. The invasion ability was decreased (27.2% +/- 2.1)% compared with (76.3% +/- 2.4%), (P < 0.05). In contrast, transfected MCF-7 cells failed to show significant difference in the expression of ERalpha and MMP-9, without change of the invasion ability (P > 0.05). RNA interference can effectively suppress the expression of MTA1 in human breast cancer cells. An induction of ERalpha protein and suppression of MMP-9 may be related to the decrease of tumor cell invasive ability. RNA interference involving MTA1 gene may provide an effective anti-cancer gene therapy.