@article{0a2fbfa53d4e4def91e62f9f4719700e,
title = "Novel mRNA isoforms and mutations of uridine monophosphate synthetase and 5-fluorouracil resistance in colorectal cancer",
abstract = "The drug fluorouracil (5-FU) is a widely used antimetabolite chemotherapy in the treatment of colorectal cancer. The gene uridine monophosphate synthetase (UMPS) is thought to be primarily responsible for conversion of 5-FU to active anticancer metabolites in tumor cells. Mutation or aberrant expression of UMPS may contribute to 5-FU resistance during treatment. We undertook a characterization of UMPS mRNA isoform expression and sequence variation in 5-FU-resistant cell lines and drug-naive or-exposed primary and metastatic tumors. We observed reciprocal differential expression of two UMPS isoforms in a colorectal cancer cell line with acquired 5-FU resistance relative to the 5-FU-sensitive cell line from which it was derived. A novel isoform arising as a consequence of exon skipping was increased in abundance in resistant cells. The underlying mechanism responsible for this shift in isoform expression was determined to be a heterozygous splice site mutation acquired in the resistant cell line. We developed sequencing and expression assays to specifically detect alternative UMPS isoforms and used these to determine that UMPS was recurrently disrupted by mutations and aberrant splicing in additional 5-FU-resistant colorectal cancer cell lines and colorectal tumors. The observed mutations, aberrant splicing and downregulation of UMPS represent novel mechanisms for acquired 5-FU resistance in colorectal cancer.",
keywords = "colorectal cancer, fluorouracil resistance, mRNA isoforms, mutation analysis, uridine monophosphate synthetase",
author = "M. Griffith and Mwenifumbo, {J. C.} and Cheung, {P. Y.} and Paul, {J. E.} and Pugh, {T. J.} and Tang, {M. J.} and S. Chittaranjan and Morin, {R. D.} and Asano, {J. K.} and Ally, {A. A.} and L. Miao and A. Lee and Chan, {S. Y.} and G. Taylor and T. Severson and Hou, {Y. C.} and Griffith, {O. L.} and Cheng, {G. S.W.} and K. Novik and R. Moore and M. Luk and D. Owen and Brown, {C. J.} and Morin, {G. B.} and S. Gill and Tai, {I. T.} and Marra, {M. A.}",
note = "Funding Information: We thank Riva Pickering for chemotherapy usage and cost statistics. We are grateful to the Ontario Tumor Bank (Ontario Institute of Cancer Research) for provision of tumor samples. We thank Susan O{\textquoteright}Reilly for support. We are grateful for funding provided by the University of British Columbia, the Michael Smith Foundation for Health Research (MSFHR), the Natural Sciences and Engineering Research Council (NSERC), Genome British Columbia, the Terry Fox Foundation (TFF), the Canadian Institutes of Health Research (CIHR), the National Cancer Institute of Canada (NCIC) and the BC Cancer Foundation. MG was supported by the NSERC, TFF and NCIC and is a Senior Graduate Trainee of the MSFHR and Genome BC. JCM is supported by CIHR and MSFHR. PYC is supported by the British Columbia Clinical Genomics Network. TJP is a Senior Graduate Trainee of the MSFHR and the BC Cancer Foundation. MJT is supported by the Canadian Digestive Health Foundation and CIHR. ITT and MAM are MSFHR scholars. MAM is a Terry Fox Young Investigator.",
year = "2013",
month = apr,
doi = "10.1038/tpj.2011.65",
language = "English",
volume = "13",
pages = "148--158",
journal = "Pharmacogenomics Journal",
issn = "1470-269X",
number = "2",
}