Mechanistic and Predictive Profiling of 5-Fluorouracil Resistance in Human Cancer Cells

Wang, W., Cassidy, J., O'Brien, V., Ryan, K. and Collie-Duguid, E. (2004) Mechanistic and Predictive Profiling of 5-Fluorouracil Resistance in Human Cancer Cells. Cancer Research, 64(22), pp. 8167-8176. (doi: 10.1158/0008-5472.CAN-04-0970)

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Gene expression was analyzed in five pairs of 5-fluorouracil (5-FU) resistant and parental cancer cell lines on DNA microarrays. In unsupervised analysis, a prediction rule was built from the expression profiles of 29 genes, and 5-FU sensitivity class was predicted with 100% accuracy and high predictive strength. In supervised analysis of key 5-FU pathways, expression of 91 genes was associated with 5-FU sensitivity phenotype and segregated samples accordingly in hierarchical analysis. Key genes involved in 5-FU activation were significantly down-regulated (thymidine kinase, 2.9-fold; orotate phosphoribosyltransferase, 2.3-fold; uridine monophosphate kinase, 3.2-fold; pyrimidine nucleoside phosphorylase 3.6-fold) in resistant cells. Overexpression of thymidylate synthase and its adjacent gene, c-Yes, was detected in the resistant cell lines. The mRNA and protein overexpression of nuclear factor kappaB (NFkappaB) p65 and related antiapoptotic c-Flip gene was detected in resistant cells. The 5-FU-resistant cell lines also showed high NFkappaB DNA-binding activity. Cotransfection of NFkappaB p50 and p65 cDNA induced 5-FU resistance in MCF-7 cells. Both NFkappaB- and 5-FU-induced resistant cell lines manifested reduced expression of genes governing G(1)-S and S-phase transition. Expression of genes involved in DNA replication was also down-regulated in resistant cell lines. These findings were highly consistent with the slower growth rate, higher proportion of G(1), and lower proportion of S-phase cells in the resistant cell lines. This phenotype may protect resistant cells from cell death induced by incorporation of 5-FU into DNA chains, by allowing time to repair 5-FU-induced damage. Our findings may provide novel targets for tackling 5-FU resistance.

Item Type:Articles
Glasgow Author(s) Enlighten ID:O'Brien, Dr Vincent and Cassidy, Professor James and Ryan, Professor Kevin
Authors: Wang, W., Cassidy, J., O'Brien, V., Ryan, K., and Collie-Duguid, E.
College/School:College of Medical Veterinary and Life Sciences > School of Cancer Sciences
Journal Name:Cancer Research

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