Premium
A comparative study on the effect of tumor promoters on poly ADP‐ribosylation in A431 cells
Author(s) -
Singh Neeta
Publication year - 1990
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910460416
Subject(s) - adp ribosylation , biology , nad+ kinase , benzamide , poly adp ribose polymerase , promoter , microbiology and biotechnology , biochemistry , tetradecanoylphorbol acetate , phorbol , enzyme , gene expression , chemistry , stereochemistry , protein kinase c , polymerase , gene
Poly ADP‐ribosylation is a post‐translational modification of chromatin proteins catalyzed by the enzyme poly‐ADPR transferase (poly‐ADPRT) and affects the structure as well as the functional properties of chromatin. It is of particular relevance in carcinogenesis, as it represents an epigenetic mechanism for modulation of gene expression. In the present study, A431 cells were exposed to tumor promoters phorbol 12‐myristate‐ 13‐acetate (PMA), benzoyl peroxide (BP), mezerein and 6‐keto‐lithocholic acid (KA), and their effect on poly‐ADP‐ribosylation was studied. All these tumor promoters increased the activity of poly‐ADPRT in these cells‐PMA 2.3‐fold, BP and mezerein 2.2‐fold each and KA 1.3‐fold. The enzyme inhibitor 3‐amino benzamide (3AB) partially prevented the stimulation of poly‐ADPRT by these promoters. There was a concomitant decrease in NAD levels, the substrate for poly‐ADPRT. The decrease was 44% for PMA, 46% for BP, 21% for KA and 34% for mezerein. The induction of poly‐ADP‐ribose synthesis by PMA and BP appears to be mediated at least in part by active oxygen species, as they induced an increase in superoxide anions and anti‐oxidants prevented the increase of poly‐ADPRT activity to varying extents.