[Effect of Inhibition of Telomerase on Cisplatin-Induced Apoptosis in HL-60 Cells]

To explore the effect of inhibition of telomerase activity on cisplatin-induced apoptosis in HL-60 cells, polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA) was used to determine telomerase activity in HL-60 cells untreated or treated with human telomerase reverse transcriptase (hTERT) gene antisense oligodeoxynucleotide (ASODN); apoptosis was detected by morphological observation and cell cycle analysis by flow cytomertry. Telomerase activity in HL-60 cells treated with hTERT ASODN was shown to decrease with time of treatment. The combination of hTERT ASODN and cisplatin could induce apoptosis of HL-60 cells. Morphological characteristics of apoptosis, such as cell shrinkage, chromatin condensation, nuclear segmentation and formation of apoptotic bodies, were observed. The percentage of apoptotic HL-60 cells treated with cisplatin for 48 or 72 hours after 24 hours of exposure to ASODN was significantly increased than that of groups with sense oligodeoxynucleotide (SODN) plus cisplatin or cisplatin alone (P < 0.01), respectively. However, there was no difference in percentage of apoptotic HL-60 cells between hTERT ASODN plus DNR or Ara-c, SODN plus DNR or Ara-c, and DNR or Ara-c alone, respectively. The results here demonstrated that inhibition of telomerase activity by hTERT ASODN could enhance the cisplatin-induced apoptosis of HL-60 cells.