EVIDENCE OF CISPLATIN-INDUCED SENESCENT-LIKE GROWTH ARREST IN NASOPHARYNGEAL CARCINOMA-CELLS

Cellular senescence is a programmed cell response leading to growth ar rest in human diploid fibroblasts, We have shown that a nasopharyngeal carcinoma cell line, CNE1, following treatment by the DNA-damaging ag ent cisplatin, can undergo cellular senescent-like growth arrest, simi lar to fibroblasts, judged by cellular morphological changes and the e xpression of senescence-associated beta-galactosidase (SA-beta-gal), T his senescent-like change was dose related; at 0.5 mu g/ml, the percen tage of cisplatin-induced SA-beta-gal-positive cells was high (40-96%) , and the staining was intense. Higher doses (1.0 and 2.0 mu g/ml) of cisplatin induced lower SA-beta-gal expression (30-70%), and the proce ss was irreversible. This cisplatin-induced cellular senescent-like re sponse was not due to the inhibition of telomerase activity. Our resul ts indicate that cellular senescent-like pathways exist in nasopharyng eal carcinoma cells and can be induced by cisplatin. Our evidence sugg ests that cellular senescent-like responses may be a cellular protecti on mechanism that acts differently in response to different degrees of cellular damage.