Inhibition of nucleic acid synthesis in P-388 lymphocytic leukemia tumor cells by helenalin and bis(helenalinyl)malonate in vivo.
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| Abstract |
Although the parent sesquiterpene lactone, helenalin, and its derivative, bis(helenalinyl)malonate, are structurally related chemically, they demonstrate differences in their antineoplastic activity, with bis(helenalinyl)malonate being much more active against P-388 lymphocytic leukemia cell growth (T/C% = 261) compared with helenalin (T/C% = 162). Previous studies have shown that both agents strongly inhibit protein synthesis in vivo by greater than 70% after 3 d of administration and in vitro by 50% at a 100 microM concentration of drug. This inhibition of protein synthesis of P-388 cells may be partially responsible for the cytotoxicity of the drug. These agents also inhibit nucleic acid synthesis in vivo, with DNA synthesis being suppressed by greater than 90% after 2 d of administration of drugs at the therapeutic dose. Of the sulfhydryl-bearing enzymes involved in nucleic acid synthesis that were assayed, only the activities of inosine-5'-monophosphate (IMP) dehydrogenase and the ribonucleotide reductase complex were inhibited by greater than 50% by these sulfhydryl-reactive drugs, which would account for the observed inhibition of nucleic acid synthesis in the P-388 cells. The inhibition of the activities of these enzymes lowered the deoxyribonucleotide levels in P-388 cells, which would explain the overall suppression of DNA synthesis by the sesquiterpene lactones.
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| Authors | W L Williams Jr, I H Hall, A A Grippo, C B Oswald, K H Lee, D J Holbrook, S G Chaney |
| Journal | Journal of pharmaceutical sciences (J Pharm Sci) Vol. 77 Issue 2 Pg. 178-84 (Feb 1988) ISSN: 0022-3549 [Print] United States |
| PMID | 2896234 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.) |
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