Constitutive nuclear factor-kappa B mRNA, protein overexpression and enhanced DNA-binding activity in thymidylate synthase inhibitor-resistant tumour cells

Weiguang Wang, J. Cassidy

    Research output: Contribution to journalArticle

    33 Citations (Scopus)

    Abstract

    In this study, the gene copy number, mRNA and protein expression levels and nuclear DNA-binding activity of nuclear factor kappa B (NF-kappaB) were compared in a panel of five pairs of thymidylate synthase (TS) inhibitor-resistant and wild-type parent cancer cell lines. High constitutive NF-kappaB DNA-binding activity was detected in all chemoresistant cell lines. The upregulated NF-kappaB activity was composed of NF-kappaB subunits p50 and p65. Four out of five resistant cell lines constitutively overexpressed NF-kappaB p50 and p63 mRNA and protein. One resistant cell line with the highest NF-kappaB DNA-binding activity showed normal p50 and p65 protein expression. No NF-kappaB gene amplification was detected in resistant cell lines. Transient exposure of wild-type RKOWT and H630(WT) cells to 5-FU induced NF-kappaB DNA-binding activity but had no effect on NF-kappaB protein expression in these cells, Our results indicate that high constitutive NF-kappaB activity caused by its gene overexpression is an intrinsic character of TS inhibitor-resistant cells. NF-kappaB can antagonise anticancer drug-induced apoptosis. High NF-kappaB expression and nuclear activity in TS inhibitor-resistant cancer cells may play an important role in the chemoresistance. (C) 2003 Cancer Research UK.

    Original languageEnglish
    Pages (from-to)624-629
    Number of pages5
    JournalBritish Journal of Cancer
    Volume88
    Issue number4
    DOIs
    Publication statusPublished - 2003

    Keywords

    • NF-kappa B
    • I kappa B alpha
    • 5-FU
    • tomudex
    • chemoresistance
    • INDUCIBLE CHEMORESISTANCE
    • TRANSCRIPTION FACTORS
    • COLORECTAL-CANCER
    • INDUCED APOPTOSIS
    • ACTIVATION
    • THERAPY
    • MECHANISMS
    • CPT-11
    • GENES

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