PURPOSE: Thymidylate synthase (TS) is a target enzyme of 5-fluorouracil. Recently, the TS gene has been shown to contain a polymorphic tandem repeat sequence. The aim of this study was to determine whether differences in the number of tandem repeats could affect gene expression or mRNA translation. EXPERIMENTAL DESIGN: We quantified TS mRNA isolated from 130 colorectal cancer tissues by real-time reverse transcription-PCR and TS protein in 92 available samples by the fluoro-dUMP binding assay. These values were compared with TS genotypes of the samples determined by a PCR assay. RESULTS: There was no relation between TS genotype and mRNA expression level. On the other hand, cancer tissues with the 3R/3R genotype had a significantly higher TS protein expression level than did those with the 2R/3R genotype. These results suggest that the efficiency of TS mRNA translation is responsible for the genotype-dependent difference in TS protein expression. Further analysis using TS 5'-untranslated region-luciferase reporter constructs showed that the RNA with the three-repeat sequence was translated three to four times more efficiently than that with two-repeat sequence. CONCLUSIONS: From the results of both in vitro and in vivo study, we conclude that TS mRNA with a three-repeat sequence has greater translation efficiency than that with the two-repeat sequence. The results provide the rationale for comprehensive usage of TS genotyping with quantitation of TS mRNA or TS protein to predict the patient's response to 5-fluorouracil-based chemotherapy.
PURPOSE:Thymidylate synthase (TS) is a target enzyme of 5-fluorouracil. Recently, the TS gene has been shown to contain a polymorphic tandem repeat sequence. The aim of this study was to determine whether differences in the number of tandem repeats could affect gene expression or mRNA translation. EXPERIMENTAL DESIGN: We quantified TS mRNA isolated from 130 colorectal cancer tissues by real-time reverse transcription-PCR and TS protein in 92 available samples by the fluoro-dUMP binding assay. These values were compared with TS genotypes of the samples determined by a PCR assay. RESULTS: There was no relation between TS genotype and mRNA expression level. On the other hand, cancer tissues with the 3R/3R genotype had a significantly higher TS protein expression level than did those with the 2R/3R genotype. These results suggest that the efficiency of TS mRNA translation is responsible for the genotype-dependent difference in TS protein expression. Further analysis using TS 5'-untranslated region-luciferase reporter constructs showed that the RNA with the three-repeat sequence was translated three to four times more efficiently than that with two-repeat sequence. CONCLUSIONS: From the results of both in vitro and in vivo study, we conclude that TS mRNA with a three-repeat sequence has greater translation efficiency than that with the two-repeat sequence. The results provide the rationale for comprehensive usage of TS genotyping with quantitation of TS mRNA or TS protein to predict the patient's response to 5-fluorouracil-based chemotherapy.
Authors: A Fariña-Sarasqueta; M J E M Gosens; E Moerland; I van Lijnschoten; V E P P Lemmens; G D Slooter; H J T Rutten; Adriaan J C van den Brule Journal: Cell Oncol (Dordr) Date: 2011-06-01 Impact factor: 6.730
Authors: Pere Domingo; M Carmen Cabeza; Alain Pruvost; Ferran Torres; Juliana Salazar; M del Mar Gutierrez; M Gracia Mateo; Angels Fontanet; Irene Fernandez; Joan C Domingo; Francesc Villarroya; Francesc Vidal; Montserrat Baiget Journal: Antimicrob Agents Chemother Date: 2011-01-31 Impact factor: 5.191
Authors: Steven Sijmons; Kim Thys; Mirabeau Mbong Ngwese; Ellen Van Damme; Jan Dvorak; Marnix Van Loock; Guangdi Li; Ruth Tachezy; Laurent Busson; Jeroen Aerssens; Marc Van Ranst; Piet Maes Journal: J Virol Date: 2015-05-13 Impact factor: 5.103