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Loss of mismatch repair activity in simian virus 40 large T antigen–immortalized BPH‐1 human prostatic epithelial cell line
Author(s) -
Yeh CheChung,
Lee Celeste,
Huang MeiChuan,
Dahiya Rajvir
Publication year - 2001
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.1049
Subject(s) - biology , dna mismatch repair , dna methylation , cancer research , cell culture , microbiology and biotechnology , gene , dna repair , gene expression , genetics
Abstract Simian virus 40 large T antigen (SVLTAg) has been used to immortalize cells; however, the mechanism leading to immortalization is still unclear. We hypothesize that DNA mismatch repair (MMR) activity is important during SVLTAg‐induced immortalization. To test this hypothesis, we used the SVLTAg‐immortalized cell line BPH‐1 derived from human benign prostate epithelial cells to analyze MMR activity and the expression of MMR genes ( hMLH1, hPMS1, hPMS2, hMSH2, hMSH3 , and hMSH6 ). The results demonstrated that BPH‐1 cells were deficient in repairing G:T, A:C, and G:G mispairs in bacteriophage M13mp2. Reverse‐transcription polymerase chain reaction experiments indicated MMR genes ( hMSH3, hMSH6, and hPMS1 ) were expressed at a low level in BPH‐1 cells. In contrast, all six MMR genes were expressed in human benign prostate hyperplasia tissues. Downregulation of hMSH3, hMSH6 , and hPMS1 genes is not a result of the hypermethylation mechanism because demethylation with 5‐aza‐2′‐deoxycytidine did not restore expression of these genes. Although the hMLH1 gene is expressed in BPH‐1 cells, western blotting and exon analyses demonstrated that hMLH1 was mutated and/or deleted in BPH‐1 cells. © 2001 Wiley‐Liss, Inc.