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Reduced Activity of Anabolizing Enzymes in 5‐Fluorouracil‐resistant Human Stomach Cancer Cells

The mechanism of resistance to 5‐fluorouracil (5‐FU) was studied with NUGC‐3/5FU/L, a human stomach cancer cell line which had acquired resistance as a consequence of repeated 5‐day exposures to stepwise‐increasing concentrations of 5‐FU in vitro. NUGC‐3/5FU/L was 200‐fold and over 16‐fold resistant...

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Autores principales: Inaba, Makoto, Mitsuhashi, Junko, Sawada, Hiroko, Miike, Naoko, Naoe, Yoshinori, Daimon, Aiko, Koizumi, Kazuhisa, Tsujimoto, Hiroaki, Fukushima, Masakazu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Blackwell Publishing Ltd 1996
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921054/
https://www.ncbi.nlm.nih.gov/pubmed/8609072
http://dx.doi.org/10.1111/j.1349-7006.1996.tb03161.x
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author Inaba, Makoto
Mitsuhashi, Junko
Sawada, Hiroko
Miike, Naoko
Naoe, Yoshinori
Daimon, Aiko
Koizumi, Kazuhisa
Tsujimoto, Hiroaki
Fukushima, Masakazu
author_facet Inaba, Makoto
Mitsuhashi, Junko
Sawada, Hiroko
Miike, Naoko
Naoe, Yoshinori
Daimon, Aiko
Koizumi, Kazuhisa
Tsujimoto, Hiroaki
Fukushima, Masakazu
author_sort Inaba, Makoto
collection PubMed
description The mechanism of resistance to 5‐fluorouracil (5‐FU) was studied with NUGC‐3/5FU/L, a human stomach cancer cell line which had acquired resistance as a consequence of repeated 5‐day exposures to stepwise‐increasing concentrations of 5‐FU in vitro. NUGC‐3/5FU/L was 200‐fold and over 16‐fold resistant to 96‐h and 1‐h exposures to 5‐FU, respectively. NUGC‐3/5FU/L incorporated less 5‐FU into RNA, indicating resistance to the RNA‐directed action of 5‐FU. On the other hand, NUGC‐3/5FU/L also showed resistance to in situ thymidylate synthase (TS) inhibition by 5‐FU. Polymerase chain reaction‐single‐strand conformation polymorphism analysis of TS cDNA and a FdUMP ligand binding assay showed that quantitative and qualitative alterations of TS are not responsible for this resistance. In contrast, the ability to metabolize 5‐FU to its active metabolites, FUTP and FdUMP, was reduced in NUGC‐3/5FU/L. We found that not only the activities of uridine phosphorylase/kinase and orotate phosphoribosyl‐transferase (OPRT), but also the level of phosphoribosyl pyrophosphate, a cosubstrate for OPRT, were significantly lower in NUGC‐3/5FU/L than in the parent NUGC‐3. These results indicated that resistance to 5‐FU in NUGC‐3/5FU/L is due to reduced activities of 5‐FU‐anabolizing enzymes, but not to an alteration of TS. 2′‐Deoxyinosine effectively enhanced TS inhibition by 5‐FU in the resistant cells, thus markedly sensitizing them to 5‐FU.
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spelling pubmed-59210542018-05-11 Reduced Activity of Anabolizing Enzymes in 5‐Fluorouracil‐resistant Human Stomach Cancer Cells Inaba, Makoto Mitsuhashi, Junko Sawada, Hiroko Miike, Naoko Naoe, Yoshinori Daimon, Aiko Koizumi, Kazuhisa Tsujimoto, Hiroaki Fukushima, Masakazu Jpn J Cancer Res Article The mechanism of resistance to 5‐fluorouracil (5‐FU) was studied with NUGC‐3/5FU/L, a human stomach cancer cell line which had acquired resistance as a consequence of repeated 5‐day exposures to stepwise‐increasing concentrations of 5‐FU in vitro. NUGC‐3/5FU/L was 200‐fold and over 16‐fold resistant to 96‐h and 1‐h exposures to 5‐FU, respectively. NUGC‐3/5FU/L incorporated less 5‐FU into RNA, indicating resistance to the RNA‐directed action of 5‐FU. On the other hand, NUGC‐3/5FU/L also showed resistance to in situ thymidylate synthase (TS) inhibition by 5‐FU. Polymerase chain reaction‐single‐strand conformation polymorphism analysis of TS cDNA and a FdUMP ligand binding assay showed that quantitative and qualitative alterations of TS are not responsible for this resistance. In contrast, the ability to metabolize 5‐FU to its active metabolites, FUTP and FdUMP, was reduced in NUGC‐3/5FU/L. We found that not only the activities of uridine phosphorylase/kinase and orotate phosphoribosyl‐transferase (OPRT), but also the level of phosphoribosyl pyrophosphate, a cosubstrate for OPRT, were significantly lower in NUGC‐3/5FU/L than in the parent NUGC‐3. These results indicated that resistance to 5‐FU in NUGC‐3/5FU/L is due to reduced activities of 5‐FU‐anabolizing enzymes, but not to an alteration of TS. 2′‐Deoxyinosine effectively enhanced TS inhibition by 5‐FU in the resistant cells, thus markedly sensitizing them to 5‐FU. Blackwell Publishing Ltd 1996-02 /pmc/articles/PMC5921054/ /pubmed/8609072 http://dx.doi.org/10.1111/j.1349-7006.1996.tb03161.x Text en
spellingShingle Article
Inaba, Makoto
Mitsuhashi, Junko
Sawada, Hiroko
Miike, Naoko
Naoe, Yoshinori
Daimon, Aiko
Koizumi, Kazuhisa
Tsujimoto, Hiroaki
Fukushima, Masakazu
Reduced Activity of Anabolizing Enzymes in 5‐Fluorouracil‐resistant Human Stomach Cancer Cells
title Reduced Activity of Anabolizing Enzymes in 5‐Fluorouracil‐resistant Human Stomach Cancer Cells
title_full Reduced Activity of Anabolizing Enzymes in 5‐Fluorouracil‐resistant Human Stomach Cancer Cells
title_fullStr Reduced Activity of Anabolizing Enzymes in 5‐Fluorouracil‐resistant Human Stomach Cancer Cells
title_full_unstemmed Reduced Activity of Anabolizing Enzymes in 5‐Fluorouracil‐resistant Human Stomach Cancer Cells
title_short Reduced Activity of Anabolizing Enzymes in 5‐Fluorouracil‐resistant Human Stomach Cancer Cells
title_sort reduced activity of anabolizing enzymes in 5‐fluorouracil‐resistant human stomach cancer cells
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921054/
https://www.ncbi.nlm.nih.gov/pubmed/8609072
http://dx.doi.org/10.1111/j.1349-7006.1996.tb03161.x
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