rTS gene expression is associated with altered cell sensitivity to thymidylate synthase inhibitors

Bruce J. Dolnick, Adrian R. Black, Patsy M. Winkler, Kim Schindler, Chung Tsen Hsueh

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

rTS is a recently discovered gene, phylogenetically conserved and found to be expressed in a wide variety of cell lines. rTS has also been found to be overexpressed in two cell lines resistant to FU and to MTX. The MTX- resistant cell line was found to have a high degree of cross resistance to several TS inhibitors. An apparent paradox to this correlation of rTS overexpression and resistance to TS inhibitors is the observation that expression of transfected rTSα results in enhanced sensitivity of cells to the TS inhibitor prodrug TFT and a modest increase in resistance to FUdR. Since immunoprecipitation of TS leads to the co-immunoprecipitation of two proteins within the expected molecular weight range of the two rTS proteins, it may be that both proteins bind to TS in vivo and modify its activity. Preliminary data substantiate this conclusion. It is conceivable that the ratio of the two rTS proteins associated with TS in vivo may differentially alter TS activity depending upon their stoichiometry or possibly posttranslational modification. Thus it may be possible for rTS to confer greater sensitivity to one pyrimidine analog (e.g., TFT) which is a product analog but to increase resistance or have a minor effect on a substrate analog (e.g., FdUMP) by stabilizing different conformations of TS. The structure of the rTS proteins suggests they are expected to have catalytic activity which involves proton abstraction from an α-carbon of a carboxyl group. Whether this enzyme activity is functional and related to pyrimidine metabolism awaits further study.

Original languageEnglish (US)
Pages (from-to)165-180
Number of pages16
JournalAdvances in Enzyme Regulation
Volume36
DOIs
StatePublished - 1996

Fingerprint

Thymidylate Synthase
Gene expression
Gene Expression
Cells
Proteins
Immunoprecipitation
Cell Line
Fluorodeoxyuridylate
Floxuridine
Prodrugs
Enzyme activity
Post Translational Protein Processing
Metabolism
Stoichiometry
Conformations
Protons
Catalyst activity
Carbon
Genes
Molecular Weight

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics
  • Cancer Research

Cite this

rTS gene expression is associated with altered cell sensitivity to thymidylate synthase inhibitors. / Dolnick, Bruce J.; Black, Adrian R.; Winkler, Patsy M.; Schindler, Kim; Hsueh, Chung Tsen.

In: Advances in Enzyme Regulation, Vol. 36, 1996, p. 165-180.

Research output: Contribution to journalArticle

Dolnick, Bruce J. ; Black, Adrian R. ; Winkler, Patsy M. ; Schindler, Kim ; Hsueh, Chung Tsen. / rTS gene expression is associated with altered cell sensitivity to thymidylate synthase inhibitors. In: Advances in Enzyme Regulation. 1996 ; Vol. 36. pp. 165-180.
@article{f751dc6d46024c2e82d829117513cdd9,
title = "rTS gene expression is associated with altered cell sensitivity to thymidylate synthase inhibitors",
abstract = "rTS is a recently discovered gene, phylogenetically conserved and found to be expressed in a wide variety of cell lines. rTS has also been found to be overexpressed in two cell lines resistant to FU and to MTX. The MTX- resistant cell line was found to have a high degree of cross resistance to several TS inhibitors. An apparent paradox to this correlation of rTS overexpression and resistance to TS inhibitors is the observation that expression of transfected rTSα results in enhanced sensitivity of cells to the TS inhibitor prodrug TFT and a modest increase in resistance to FUdR. Since immunoprecipitation of TS leads to the co-immunoprecipitation of two proteins within the expected molecular weight range of the two rTS proteins, it may be that both proteins bind to TS in vivo and modify its activity. Preliminary data substantiate this conclusion. It is conceivable that the ratio of the two rTS proteins associated with TS in vivo may differentially alter TS activity depending upon their stoichiometry or possibly posttranslational modification. Thus it may be possible for rTS to confer greater sensitivity to one pyrimidine analog (e.g., TFT) which is a product analog but to increase resistance or have a minor effect on a substrate analog (e.g., FdUMP) by stabilizing different conformations of TS. The structure of the rTS proteins suggests they are expected to have catalytic activity which involves proton abstraction from an α-carbon of a carboxyl group. Whether this enzyme activity is functional and related to pyrimidine metabolism awaits further study.",
author = "Dolnick, {Bruce J.} and Black, {Adrian R.} and Winkler, {Patsy M.} and Kim Schindler and Hsueh, {Chung Tsen}",
year = "1996",
doi = "10.1016/0065-2571(95)00009-7",
language = "English (US)",
volume = "36",
pages = "165--180",
journal = "Advances in Biological Regulation",
issn = "2212-4926",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - rTS gene expression is associated with altered cell sensitivity to thymidylate synthase inhibitors

AU - Dolnick, Bruce J.

AU - Black, Adrian R.

AU - Winkler, Patsy M.

AU - Schindler, Kim

AU - Hsueh, Chung Tsen

PY - 1996

Y1 - 1996

N2 - rTS is a recently discovered gene, phylogenetically conserved and found to be expressed in a wide variety of cell lines. rTS has also been found to be overexpressed in two cell lines resistant to FU and to MTX. The MTX- resistant cell line was found to have a high degree of cross resistance to several TS inhibitors. An apparent paradox to this correlation of rTS overexpression and resistance to TS inhibitors is the observation that expression of transfected rTSα results in enhanced sensitivity of cells to the TS inhibitor prodrug TFT and a modest increase in resistance to FUdR. Since immunoprecipitation of TS leads to the co-immunoprecipitation of two proteins within the expected molecular weight range of the two rTS proteins, it may be that both proteins bind to TS in vivo and modify its activity. Preliminary data substantiate this conclusion. It is conceivable that the ratio of the two rTS proteins associated with TS in vivo may differentially alter TS activity depending upon their stoichiometry or possibly posttranslational modification. Thus it may be possible for rTS to confer greater sensitivity to one pyrimidine analog (e.g., TFT) which is a product analog but to increase resistance or have a minor effect on a substrate analog (e.g., FdUMP) by stabilizing different conformations of TS. The structure of the rTS proteins suggests they are expected to have catalytic activity which involves proton abstraction from an α-carbon of a carboxyl group. Whether this enzyme activity is functional and related to pyrimidine metabolism awaits further study.

AB - rTS is a recently discovered gene, phylogenetically conserved and found to be expressed in a wide variety of cell lines. rTS has also been found to be overexpressed in two cell lines resistant to FU and to MTX. The MTX- resistant cell line was found to have a high degree of cross resistance to several TS inhibitors. An apparent paradox to this correlation of rTS overexpression and resistance to TS inhibitors is the observation that expression of transfected rTSα results in enhanced sensitivity of cells to the TS inhibitor prodrug TFT and a modest increase in resistance to FUdR. Since immunoprecipitation of TS leads to the co-immunoprecipitation of two proteins within the expected molecular weight range of the two rTS proteins, it may be that both proteins bind to TS in vivo and modify its activity. Preliminary data substantiate this conclusion. It is conceivable that the ratio of the two rTS proteins associated with TS in vivo may differentially alter TS activity depending upon their stoichiometry or possibly posttranslational modification. Thus it may be possible for rTS to confer greater sensitivity to one pyrimidine analog (e.g., TFT) which is a product analog but to increase resistance or have a minor effect on a substrate analog (e.g., FdUMP) by stabilizing different conformations of TS. The structure of the rTS proteins suggests they are expected to have catalytic activity which involves proton abstraction from an α-carbon of a carboxyl group. Whether this enzyme activity is functional and related to pyrimidine metabolism awaits further study.

UR - http://www.scopus.com/inward/record.url?scp=0030458182&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030458182&partnerID=8YFLogxK

U2 - 10.1016/0065-2571(95)00009-7

DO - 10.1016/0065-2571(95)00009-7

M3 - Article

C2 - 8869746

AN - SCOPUS:0030458182

VL - 36

SP - 165

EP - 180

JO - Advances in Biological Regulation

JF - Advances in Biological Regulation

SN - 2212-4926

ER -