MCPIP1 induces cell cycle arrest in breast cancer cell line MDA-MB-231 / 基础医学与临床

ABSTRACT

Objective To investigate the functions of Monocyte chemotactic protein-induced protein 1 (MCPIP1) in human breast cancer cell line MDA-MB-231.Methods MDA-MB-231 cells were transfected with GFP-tagged MCPIP1 by Tet-on inducing expression system.Endogenous MCPIP1 was knocked down by stable expressing shRNA.MTT assay was performed to measure the growth of MDA-MB-231 cells after overexpression or knockdown of MCPIP1.FACS method was used to analyze cell cycle in MDA-MB-231 cells.Real-time PCR was used to test the expression of cell cycle-related mRNAs expression and their half-lives.RNA-IP experiment was conducted to detect the mRNA directly enriched by MCPIP1.Luciferase assay was performed to determine whether the mRNA decay was mediated through 3′UTR.Results MCPIP1 overexpression significantly inhibited cell proliferation(P<0.05), while knockdown MCPIP1 promoted cell proliferation with statistical significances (P<0.05).MCPIP1 induced cell cycle arrest in MDA-MB-231 with statistical significance (P<0.01).MCPIP1 overexpression reduced the half-lives of cell cycle mRNAs (CDK2,CDK6,cyclin D1,cyclin E1,respectively) with significance (P<0.01).In addition, cell cycle-related mRNAs were able to be pulled down by GFP-MCPIP1 but not isotype IgG(P<0.05).Compared with control vector, MCPIP1 significant suppressed luciferase activities of all four 3′UTR reporters (P<0.05).Conclusions MCPIP1 functions as a tumor suppressor in human breast cancer cell line MDA-MB-231 through inducing G1 cell cycle arrest.