THE INFLUENCE OF TELOMERASE hTRT GENE ANTISENSE OLIGONUCLEOTIDE ON ITS ENZYMIC ACTIVITY AND PROLIFERATION OF TUMOR CELL

Objective\ To study the effect of human telomerase reverse transcriptase antisense oligonucleotide(hTRT ASO)on its enzymic activity and proliferation of tumor cells. \ Methods\ MTT assay was used to detect the effect of hTRT ASO on proliferation of tumor cell line HL 60. Telomeres repeat amplification protocol(TRAP PCR) was used to study the changes of telomerase activity of tumor cells treated by hTRT ASO. Giemsa stain and light microscope were used to observe the morphological changes of tumor cells after treatment by hTRT ASO.DNA gel electrophoresis and diphenylamine assay were used to test DNA fragmentation of HL 60 cells treated by hTRT ASO. \ Results\ The proliferation of HL 60 cells was inhibited after treatment by hTRT ASO for 48 hours. The telomerase activity decreased after treatment by hTRT ASO(5μmol/L) for 24 hours. The telomerase activity decreased constantly with prolongation of time. The telomerase activity of tumor cell treated for 96 hours was 44.4% of the control. HL 60 cells treated by hTRT ASO (5μmol/L) for 96 hours appeared standard apoptotic morphological characters. Apoptotic indexes of HL 60 treated for 24, 48, 72 and 96 hours were 0.053, 0.127, 0.257 and 0.315, respectively. DNA ladder of HL 60 cells was detected by gel electrophoresis after treatment by hTRT ASO (5μmol/L )for 96 hours. DNA fragmentation ratio of HL 60 cells treated by hTRT ASO for 24, 48, 72 and 96 hours was 17.98%, 29.34%, 35.43% and 41.24% respectively. Conclusion\ hTRT ASO can inhibit the proliferation of tumor cells and the activity of telomerase and induce apoptosis of tumor cells.