Inhibition of telomerase with human telomerase reverse transcriptase antisense increases the sensitivity of tumor necrosis factor-alpha-induced apoptosis in prostate cancer cells.
OBJECTIVE
To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase (hTERT) antisense on tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis in prostate cancer cells (PC3).


METHODS
Antisense phosphorothioate oligodeoxynucleotide (AS PS-ODN) was synthesized and purified. Telomerase activity was measured using the telomeric repeat amplification protocol (TRAP) and polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA). hTERT mRNA was measured by reverse transcription PCR (RT-PCR) assay and gel-image system. hTERT protein was detected by immunochemistry and flow cytometry. Cell viability was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium (MTT) assay. Cell apoptosis was observed by morphological method and determined by flow cytometry.


RESULTS
The telomerase activity decreased with time after hTERT AS PS-ODN treatment. The levels of hTERT mRNA decreased with time after hTERT AS PS-ODN treatment, which appeared before the decline of the telomerase activity. The percentage of positive cells of hTERT protein declined with time after hTERT AS PS-ODN treatment, which appeared after the decline of hTERT mRNA. There was no difference in telomerase activity, hTERT mRNA and protein levels between hTERT sense phosphorothioate oligodeoxynucleotide (S PS-ODN) and the control group. The cell viability decreased with time after hTERT AS PS-ODN combined with TNF-alphatreatment. The percentage of apoptosis increased with time after hTERT AS PS-ODN combined with TNF-alpha treatment. There was no difference in cell viability and the percentage of apoptosis between hTERT S PS-ODN and the control group.


CONCLUSIONS
hTERT AS PS-ODN can significantly inhibit telomerase activity by downregulating the hTERT mRNA and protein expression, and inhibition of telomerase with hTERT antisense can enhance TNF-alpha-induced apoptosis of PC3 cells.
Gao
Xiao-Dong
XD
Department of Urology, Lanzhou University, Lanzhou 730000, China. gxd58038@yahoo.com.cn
Chen
Yi-Rong
YR
D000199:Actins / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D017931:DNA Primers; D006801:Humans; D008297:Male; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology; D011471:Prostatic Neoplasms; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019098:Telomerase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D000199:Actins; D017931:DNA Primers; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D019098:Telomerase