Inhibition of tankyrase 1 in human gastric cancer cells enhances telomere shortening by telomerase inhibitors.
Telomere stability is believed to be related to aging and tumorigenesis. Besides telomerase, telomere length is also regulated by several telomere-specific binding proteins. Tankyrase 1, a telomeric poly(ADP-ribose) polymerase (PARP), elongates telomere length by inhibiting TRF1 binding to telomeres. In order to study the synergistic action of tankyrase 1 and telomerase in the maintenance of telomere length in mammalian cells, we constructed anti-sense tankyrase 1 (aTNKS) eukaryotic expression vectors and then transfected them into the SGC-7901 human gastric cancer cell line, as well as SGC-7901 cells that had been transfected with antisense hTR (7901-ahTR) and antisense hTERT (7901-ahTERT) with DOTAP liposomes. The activity of telomerase, telomere length and telomerase-associated protein activities were measure by TRAP-ELISA, Southern blot and western blot analysis, respectively, in aTNKS transfected and untransfected cells. The results demonstrated that telomere length was significantly shorter in cells with concomitant tankyrase 1 and telomerase inhibition than by either tankyrase 1 or telomerase inhibition alone, in SGC-7901 cells. We also found that aTNKS had no effect on telomerase activity. These results reveal that inhibition of tankyrase 1 could shorten telomere length and play a synergistic role with telomerase inhibitors in telomere length shortening in the SGC-7901 gastric cancer cell line. Co-inhibition of tankyrase 1 and telomerase activity may be a rational strategy for telomere-directed gastric cancer therapeutics.
Zhang
Hao
H
Institute of Gastroenterology, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China.
Yang
Meng-Hua
MH
Zhao
Jing-Jing
JJ
Chen
Ling
L
Yu
Song-Tao
ST
Tang
Xu-Dong
XD
Fang
Dian-Chun
DC
Yang
Shi-Ming
SM
D015139:Blotting, Southern; D015153:Blotting, Western; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000235:genetics*; D038501:Tankyrases / Q000378:metabolism*; D019098:Telomerase / Q000378:metabolism*; D016615:Telomere / Q000187:drug effects / Q000378:metabolism*; D014162:Transfection
D004791:Enzyme Inhibitors; D038501:Tankyrases; D019098:Telomerase; C418109:TNKS protein, human