COMBINED EFFECTS OF STREPTOZOTOCIN AND MITOZOLOMIDE AGAINST 4 HUMAN CELL-LINES OF THE MER+ PHENOTYPE
- 1 October 1986
- journal article
- research article
- Vol. 46 (10) , 4995-4998
Abstract
The majority of human tumor cell lines are proficient in the repair of guanine O6-alkylations (designated Mer+) and are thus capable of preventing the cytotoxic effects of chloroethylating agents. It has been proposed that in these cells guanine O6-chloroethylations are rapidly removed by the enzyme O6-alkylguanine DNA alkyltransferase before the formation of DNA interstrand cross-links can occur. In this study pretreatment of four Mer+ human cells (A2182 lung carcinoma, A375 melanoma, HT-29 colon carcinoma, and IMR-90 normal lung fibroblasts) with the DNA methylating agent streptozotocin apparently saturates the monoadduct repair system and allows mitozolomide to form interstrand cross-links in these cells. The inhibition of the alkyltransferase results in the continued presence of guanine O6-chloroethylations which then undergo a series of reactions that lead to DNA interstrand cross-link formation. As observed by colony forming assays, streptozotocin pretreatment causes a dramatic increase in the sensitivity of these four Mer+ cell lines to the cytotoxic effects of mitozolomide. These results indicate that a combination of streptozotocin pretreatment followed by mitozolomide may be useful in the treatment of human cancer.This publication has 16 references indexed in Scilit:
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