Effect Of Human Telomerase RNA (hTR) Antisense On Telomerase Activity And Chemotherapeutic Drugs-induced Apoptosis In K562/HL-60 Cell Lines

Objective: To investigate the effectjof human telomerase RNA (hTR) antisensephosphoro-thioate oligodeoxynucleotide(AS PS-ODN) on telomerase activity and apoptosis induced by chemotherapeutic drugs in K562 , HL-60 cell lines. Methods: Polymerase chain rea-ction -enzyme linked immunoassay (PCR-ELISA) was used to assay telomerase activity. The survival rates of cells was measured by trypan blue exclusion. Apoptosis was assay-ed by morphological observation, DNA gel electro-phoresis and flow cytometry analysis technology.Results: K562 and HL-60 cells all expressed high level of telomerase activity, which decreased as the cells treated by hTR AS PS-ODN. It was found that there was no significant difference in survival rate between cells treated with hTR AS PS-ODN added Daunorubicin(DNR), Araninosyl Cytosine(Ara-C) and Etoposide(VP16) respectively 24h later and DNR, VCR and VP16 respectively (P>0. 05). The survival rate of K562, HL-60 cells cultured with cis-diamminedichicloroplatinum(CDDP) added 24h later was higher than that cultured with hTR AS PS-ODN plus CDDP added 24h later (P<0.05). There was no significant difference between cells added CDDP and cells added CDDP/ hTR S PS-ODN (P>0. 05). In morphological observation of apoptotic cells using Giemsa stain-ing and Annexin V and PI double staining techniques, cells displayed classic apoptotic changes treated with CDDP alone and CDDP plus hTR AS PS-ODN or S PS-ODN at 48h. In this part, the number of apoptotic cells treated with CDDP and hTR AS PS-ODN toge-ther is obviously more than that treated with CDDP alone and CDDP combined with hTR S PS-ODN, and it was similar in cells treated with CDDP alone and CDDP combined with hTR S PS-ODN. Genomic DNA of K562 and HL-60 cells treated with hTR AS PS-ODN and CDDP(5μmol/L) added 24h later showed typical DNA "ladder" through agaro-se gel electrophoresis in 48h; Neither did geno-mic DNA from cells treated with CDDP /S PS-ODN nor CDDP alone. Apoptotic rates of K562 and HL-60 cells were detected by flow cytometry assay. Apoptotic rates ofcells added CDDP ( 5βmol/L) /AS PS-ODN were higher than that of cells added CDDP( 5βmol/L) only (P<0.01). It was similar in cells added CDDP( 5βmol/L)/ S PS-ODN and CDDP( 5βmol/L) only (P>0.05). Conclusions: hTR AS PS-ODN could inhibit telomerase activity of K562 ,HL-60 cells , and in-creased the CDDP-induced apoptosis and enhanced CDDP-sensitivity.But it could not incerased the DNA&Ara-C&VP16-induced apoptosis.