Document Detail


Structure-activity studies of novobiocin analogs as modulators of the cytotoxicity of etoposide (VP-16).
MedLine Citation:
PMID:  11216669     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have previously reported that the antibiotic novobiocin enhanced the toxicity of the anticancer agent etoposide (VP-16) to several drug-sensitive and -resistant tumor cell lines. The increase in VP-16 cytotoxicity produced by novobiocin was not due to the combined effects of these agents on topoisomerase II, but to inhibition by novobiocin of VP-16 efflux, which in turn led to increased accumulation of VP-16 and increased formation of potentially lethal VP-16-stabilized topoisomerase II-DNA covalent complexes. We have now identified novobiocin analogs that are essentially equivalent to novobiocin as inhibitors of the activity of topoisomerase II, but that are more potent than novobiocin (a) as modulators of the cytotoxicity of VP-16 to WEHI-3B leukemia and A549 lung carcinoma cells and (b) in increasing VP-16 accumulation in these cell lines. Thus, removal of the sugar moiety of novobiocin to form novobiocic acid enhanced the potency of the antibiotic as a modulator of VP-16, whereas the substituted coumarin ring alone (U-7587) was devoid of VP-16 modulatory activity. Modifications of the side chain of novobiocin significantly influenced modulatory activity, with cyclonovobiocic acid, which was formed from novobiocic acid by acid-catalyzed cycloaddition, being the most active in enhancing the cytotoxicity of VP-16. The increased potency of novobiocic acid and cyclonovobiocic acid as modulators of VP-16 activity was achieved with no change from novobiocin in the capacity of these analogs to inhibit the catalytic activity of mammalian topoisomerase II, indicating a change in the specificity of these analogs.
Authors:
G Rappa; K Shyam; A Lorico; O Fodstad; A C Sartorelli
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Oncology research     Volume:  12     ISSN:  0965-0407     ISO Abbreviation:  Oncol. Res.     Publication Date:  2000  
Date Detail:
Created Date:  2001-02-16     Completed Date:  2001-04-12     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  9208097     Medline TA:  Oncol Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  113-9     Citation Subset:  IM    
Affiliation:
Department of Tumor Biology, Norwegian Radium Hospital, Montebello, Oslo.
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MeSH Terms
Descriptor/Qualifier:
ATP-Binding Cassette Transporters / physiology
Adenosine Triphosphate / pharmacology
Antineoplastic Agents, Phytogenic / pharmacology*
DNA Topoisomerases, Type II / antagonists & inhibitors*
Drug Synergism
Enzyme Inhibitors / pharmacology*
Etoposide / pharmacology*
Humans
Multidrug Resistance-Associated Proteins
Novobiocin / pharmacology*
Structure-Activity Relationship
Tumor Cells, Cultured
Grant Support
ID/Acronym/Agency:
CA-66739/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/ATP-Binding Cassette Transporters; 0/Antineoplastic Agents, Phytogenic; 0/Enzyme Inhibitors; 0/Multidrug Resistance-Associated Proteins; 303-81-1/Novobiocin; 33419-42-0/Etoposide; 56-65-5/Adenosine Triphosphate; EC 5.99.1.3/DNA Topoisomerases, Type II

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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