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Functional analysis of the mismatch repair system in bladder cancer

In bladder cancer the observed microsatellite instability indicates that mismatch repair deficiency could be a frequently involved factor in bladder cancer progression. To investigate this hypothesis we analysed extracts of seven bladder cancer cell lines and, as a novel approach, five clinical canc...

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Autores principales: Thykjaer, T, Christensen, M, Clark, A B, Hansen, L R T, Kunkel, T A, Ørntoft, T F
Formato: Texto
Lenguaje:English
Publicado: Nature Publishing Group 2001
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2364098/
https://www.ncbi.nlm.nih.gov/pubmed/11506498
http://dx.doi.org/10.1054/bjoc.2001.1949
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author Thykjaer, T
Christensen, M
Clark, A B
Hansen, L R T
Kunkel, T A
Ørntoft, T F
author_facet Thykjaer, T
Christensen, M
Clark, A B
Hansen, L R T
Kunkel, T A
Ørntoft, T F
author_sort Thykjaer, T
collection PubMed
description In bladder cancer the observed microsatellite instability indicates that mismatch repair deficiency could be a frequently involved factor in bladder cancer progression. To investigate this hypothesis we analysed extracts of seven bladder cancer cell lines and, as a novel approach, five clinical cancer samples for mismatch repair activity. We found that one cell line (T24) and three of the clinical samples had a reduced repair capacity, measured to ~20% or less. The T24 cell extract was unable to repair a G-G mismatch and showed reduced repair of a 2-base loop, consistent with diminished function of the MSH2-MSH6 heterodimer. The functional assay was combined with measurement for mutation frequency, microsatellite analysis, sequencing, MTT assay, immunohistochemical analysis and RT-PCR analysis of the mismatch repair genes MSH2, MSH3, MSH6, PMS1, PMS2 and MLH1. A >7-fold relative increase in mutation frequency was observed for T24 compared to a bladder cancer cell line with a fully functional mismatch repair system. Neither microsatellite instability, loss of repair nor mismatch repair gene mutations were detected. However, RT-PCR analysis of mRNA levels did detect changes in the ratio of expression of the Mut S and Mut L homologues. The T24 cell line had the lowest MSH6 expression level of the cell lines tested. Identical RT-PCR analysis of seventeen clinical samples (normal urothelium, 7; pTa low stage, 5; and pT1-4 high stage, 5) indicated a significant change in the expression ratio between MSH3/MSH6 (P< 0.004), MSH2/MSH3 (P< 0.012) and PMS2/MLH1 P< 0.005, in high stage bladder tumours compared to normal urothelium and low stage tumours. Collectively, the data suggest that imbalanced expression of mismatch repair genes could lead to partial loss of mismatch repair activity that is associated with invasive bladder cancer. © 2001 Cancer Research Campaign http://www.bjcancer.com
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spelling pubmed-23640982009-09-10 Functional analysis of the mismatch repair system in bladder cancer Thykjaer, T Christensen, M Clark, A B Hansen, L R T Kunkel, T A Ørntoft, T F Br J Cancer Regular Article In bladder cancer the observed microsatellite instability indicates that mismatch repair deficiency could be a frequently involved factor in bladder cancer progression. To investigate this hypothesis we analysed extracts of seven bladder cancer cell lines and, as a novel approach, five clinical cancer samples for mismatch repair activity. We found that one cell line (T24) and three of the clinical samples had a reduced repair capacity, measured to ~20% or less. The T24 cell extract was unable to repair a G-G mismatch and showed reduced repair of a 2-base loop, consistent with diminished function of the MSH2-MSH6 heterodimer. The functional assay was combined with measurement for mutation frequency, microsatellite analysis, sequencing, MTT assay, immunohistochemical analysis and RT-PCR analysis of the mismatch repair genes MSH2, MSH3, MSH6, PMS1, PMS2 and MLH1. A >7-fold relative increase in mutation frequency was observed for T24 compared to a bladder cancer cell line with a fully functional mismatch repair system. Neither microsatellite instability, loss of repair nor mismatch repair gene mutations were detected. However, RT-PCR analysis of mRNA levels did detect changes in the ratio of expression of the Mut S and Mut L homologues. The T24 cell line had the lowest MSH6 expression level of the cell lines tested. Identical RT-PCR analysis of seventeen clinical samples (normal urothelium, 7; pTa low stage, 5; and pT1-4 high stage, 5) indicated a significant change in the expression ratio between MSH3/MSH6 (P< 0.004), MSH2/MSH3 (P< 0.012) and PMS2/MLH1 P< 0.005, in high stage bladder tumours compared to normal urothelium and low stage tumours. Collectively, the data suggest that imbalanced expression of mismatch repair genes could lead to partial loss of mismatch repair activity that is associated with invasive bladder cancer. © 2001 Cancer Research Campaign http://www.bjcancer.com Nature Publishing Group 2001-08 /pmc/articles/PMC2364098/ /pubmed/11506498 http://dx.doi.org/10.1054/bjoc.2001.1949 Text en Copyright © 2001 Cancer Research Campaign https://creativecommons.org/licenses/by/4.0/This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material.If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.
spellingShingle Regular Article
Thykjaer, T
Christensen, M
Clark, A B
Hansen, L R T
Kunkel, T A
Ørntoft, T F
Functional analysis of the mismatch repair system in bladder cancer
title Functional analysis of the mismatch repair system in bladder cancer
title_full Functional analysis of the mismatch repair system in bladder cancer
title_fullStr Functional analysis of the mismatch repair system in bladder cancer
title_full_unstemmed Functional analysis of the mismatch repair system in bladder cancer
title_short Functional analysis of the mismatch repair system in bladder cancer
title_sort functional analysis of the mismatch repair system in bladder cancer
topic Regular Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2364098/
https://www.ncbi.nlm.nih.gov/pubmed/11506498
http://dx.doi.org/10.1054/bjoc.2001.1949
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