Abstract: Objective To construct the silencing vector of FOS like antigen 1 (FOSL1) gene, and study the effects of FOSL1 on cell proliferation, cell invasiveness and the methylation level of PRDM10 gene in breast cancer cell line MDAMB-231. Methods The FOSL1 silencing vector of gene pLVX-shRNA-FOSL1-shRNA was purchased. The FOSL1 silencing vector and the empty vector were separately transfected into MDA-MB-231, which were regarded as transfection group and empty group, respectively. Untransfected MDA-MB-231 was used as control group. FOSL1 was verified by PCR in MDA-MB-231. The cell proliferation ability and cell invasion ability of MDA-MB-231 were detected by MTT and Transwell assay, respectively. MSP was used to detect the methylation status of PRDM10 gene. The mRNA and protein expression levels of PRDM10 gene were detected by Q-PCR and Western-blot assay. Results MTT results showed that the optical density (OD) values were significantly lower in transfection group compared with those of control group at 24 h, 48 h and 72 h (all P<0.05), and the same as those compared with empty group at 48 h and 72 h (both P<0.05). Compared with empty group and control group, Transwell assays showed that the cell invasive abilities of MDA-MB-231 were decreased in transfection group (both P<0.05), and MSP assay showed that the methylation of PRDM10 gene was decreased in MDA-MB- 231, and Q-PCR and Western-blot tests showed that the expressions of PRDM10 gene were increased in mRNA level and in protein level. Conclusion Silencing of FOSL1 gene inhibits the proliferation and invasion of MDA-MB-231 cells, which might be related to the demethylation of PRDM10 gene in the cells.

Key words: breast neoplasms, cell proliferation, cell invasion, FOSL1, PRDM10