A miR-200b/200c/429-binding site polymorphism in the 3' untranslated region of the AP-2? gene is associated with cisplatin resistance.

ABSTRACT: The transcription factor AP-2? functions as a tumor suppressor by regulating various genes that are involved in cell proliferation and apoptosis. Chemotherapeutic drugs including cisplatin induce post-transcriptionally endogenous AP-2?, which contributes to chemosensitivity by enhancing therapy-induced apoptosis. microRNAs (miRNAs) miR-200b, miR-200c and miR-429 (miR-200b/200c/429) are up-regulated in endometrial and esophageal cancers, and their overexpression correlates with resistance to cisplatin treatment. Using computational programs, we predicted that the 3' untranslated region (UTR) of AP-2? gene contains a potential miRNA response element (MRE) for the miR-200b/200c/429 family, and the single nucleotide polymorphism (SNP) site rs1045385 (A or C allele) resided within the predicted MRE. Luciferase assays and Western blot analysis demonstrated that the miR-200b/200c/429 family recognized the MRE in the 3' UTR of AP-2? gene and negatively regulated the expression of endogenous AP-2? proteins. SNP rs1045385 A>C variation enhanced AP-2? expression by disrupting the binding of the miR-200b/200c/429 family to the 3' UTR of AP-2?. The effects of the two polymorphic variants on cisplatin sensitivity were determined by clonogenic assay. The overexpression of AP-2? with mutant 3' UTR (C allele) in the endometrial cancer cell line HEC-1A, which has high levels of endogenous miR-200b/200c/429 and low levels of AP-2? protein, significantly increased cisplatin sensitivity, but overexpression of A allele of AP-2? has no significant effects, compared with mock transfection. We concluded that miR-200b/200c/429 induced cisplatin resistance by repressing AP-2? expression in endometrial cancer cells. The SNP (rs1045385) A>C variation decreased the binding of miR-200b/200c/429 to the 3' UTR of AP-2?, which upregulated AP-2? protein expression and increased cisplatin sensitivity. Our results suggest that SNP (rs1045385) may be a potential prognostic marker for cisplatin treatment.

SUBMITTER: Wu Y 

PROVIDER: S-EPMC3237583 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature