[Effect of antisense oligodeoxynucleotides of RNA component of human telomerase on cisplatin induced apoptosis in K562 cells].

OBJECTIVE: To research whether the antisense oligodeoxynucleotide (ASODN) of RNA component of human telomerase (hTR) can increase the susceptibility of K562 cells to cisplatin. METHODS: K562 cells were treated with phosphorothoate ASODN complementary to the template region of hTR in vivo. The changing of telomerase activity was assayed by TRAP-PCR-ELISA and apoptosis by DNA gel electrophoresis, Annexin V, flow cytometry. RESULTS: There was a marked decrease in telomerase activity in ASODN treated cells 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 ladder 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 were statistically significant difference in the percentage of apoptotic cells between hTR ASODN plus cisplatin and SODN plus cisplatin or cisplatin alone group. CONCLUSION: ASODN complementary to the template region of hTR can significantly suppress the telomerase activity and enhance cisplatin-induced apoptosis of K562 cells in vivo.