Radioresistant derivatives of radiosensitive CHO cells obtained following treatment with 5-azacytidine retain their sensitivity to cisplatin.
Treatment of the radiation-sensitive CHO mutant, xrs-5, with the demethylating agent 5-azacytidine results in the complete conversion to wild-type levels of X-ray resistance in 50% of the colonies examined (10/20). In addition to being sensitive to X rays, xrs-5 is also sensitive to the killing effects of the crosslinking agent cisplatin. The 5-azacytidine-treated xrs-5 cells which exhibit wild-type survival levels following exposure to X rays failed to demonstrate conversion to wild-type levels of resistance to cisplatin. These results support the hypothesis that increases in gene expression can alter the radioresistance of xrs-5 cells without influencing the cells' survival after exposure to cisplatin.
Haraf
D J
DJ
University of Chicago, Department of Radiation and Cellular Oncology, Illinois 60637.
Drucker
D R
DR
Weichselbaum
R R
RR
Diamond
A M
AM
D000818:Animals; D001374:Azacitidine / Q000494:pharmacology*; D016466:CHO Cells; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002945:Cisplatin / Q000494:pharmacology*; D006224:Cricetinae; D004361:Drug Tolerance; D011836:Radiation Tolerance
D001374:Azacitidine; D002945:Cisplatin