[Effect of inhibition of telomerase activity on cisplatin-induced apoptosis in K562 cells].

OBJECTIVE: To explore the effect of human telomerase reverse transcriptase (hTERT) gene antisense oligodeoxynucleotide (ASODN) on telomerase activity and cisplatin-induced apoptosis in K562 cells. METHODS: Telomerase activity was analyzed by using polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA), expression levels of hTERT protein by immunofluorescence and apoptosis by DNA gel electrophoresis and flow cytometry. RESULTS: There was a marked decrease in both the percentage of hTERT protein positive cells and the telomerase activity in ASODN treated cell as compared with that in control and sense oligodeoxynucleotide (SODN)-treated cells; but no difference between the latter two groups. Agarose gel electrophoresis of genomic DNA from K562 cells treated with ASODN and cisplatin combination for 72 h showed typical DNA ladder; neither did DNA from K562 cells treated with SODN plus cisplatin nor cisplatin alone. Apoptosis rates of K562 cells treated with ASODN for 24 h and then with cisplatin for 72 h were significantly increased. There was statistically significant difference in the percentage of apoptotic cells between hTERT ASODN plus cisplatin group and SODN plus cisplatin or cisplatin alone group. CONCLUSION: The hTERT gene ASODN could inhibit telomerase activity of K562 cells whereby it enhanced cisplatin-induced apoptosis of the cells.