TY - JOUR
T1 - Deregulated GSK3β sustains gastrointestinal cancer cells survival by modulating human telomerase reverse transcriptase and telomerase
AU - Mai, Wei
AU - Kawakami, Kazuyuki
AU - Shakoori, Abbas
AU - Kyo, Satoru
AU - Miyashita, Katsuyoshi
AU - Yokoi, Kenji
AU - Jin, Mingji
AU - Shimasaki, Takeo
AU - Motoo, Yoshiharu
AU - Minamoto, Toshinari
PY - 2009/11/15
Y1 - 2009/11/15
N2 - Purpose: Glycogen synthase kinase-3β (GSK3β) regulates multiple cell signaling pathways and has been implicated in glucose intolerance, neurodegenerative disorders, and inflammation. We investigated the expression, activity, and putative pathologic role of GSK3β in gastrointestinal, pancreatic, and liver cancers. Experimental Design: Colon, stomach, pancreatic, and liver cancer cell lines; nonneoplastic HEK293 cells; and matched pairs of normal and tumor tissues of stomach and colon cancer patients were examined for GSK3β expression and its phosphorylation at serine 9 (inactive form) and tyrosine 216 (active form) by Western immunoblotting and for GSK3β activity by in vitro kinase assay. The effects of small-molecule GSK3β inhibitors and of RNA interference on cell survival, proliferation, and apoptosis were examined in vitro and on human colon cancer cell xenografts in athymic mice. The effects of GSK3β inhibition on human telomerase reverse transcriptase (hTERT) expression and telomerase activity were compared between colon cancer and HEK293 cells. Results: Cancer cell lines and most cancer tissues showed increased GSK3β expression and increased tyrosine 216 phosphorylation and activity but decreased serine 9 phosphorylation compared with HEK293 cells and nonneoplastic tissues. Inhibition of GSK3β resulted in attenuated cell survival and proliferation and increased apoptosis in most cancer cell lines and in HT-29 xenografts in rodents but not in HEK293 cells. GSK3β inhibition in colon cancer cells was associated with decreased hTERT expression and telomerase activity. Conclusion: The results indicate that deregulated GSK3β sustains gastrointestinal cancer cells survival through modulation of hTERT and telomerase.
AB - Purpose: Glycogen synthase kinase-3β (GSK3β) regulates multiple cell signaling pathways and has been implicated in glucose intolerance, neurodegenerative disorders, and inflammation. We investigated the expression, activity, and putative pathologic role of GSK3β in gastrointestinal, pancreatic, and liver cancers. Experimental Design: Colon, stomach, pancreatic, and liver cancer cell lines; nonneoplastic HEK293 cells; and matched pairs of normal and tumor tissues of stomach and colon cancer patients were examined for GSK3β expression and its phosphorylation at serine 9 (inactive form) and tyrosine 216 (active form) by Western immunoblotting and for GSK3β activity by in vitro kinase assay. The effects of small-molecule GSK3β inhibitors and of RNA interference on cell survival, proliferation, and apoptosis were examined in vitro and on human colon cancer cell xenografts in athymic mice. The effects of GSK3β inhibition on human telomerase reverse transcriptase (hTERT) expression and telomerase activity were compared between colon cancer and HEK293 cells. Results: Cancer cell lines and most cancer tissues showed increased GSK3β expression and increased tyrosine 216 phosphorylation and activity but decreased serine 9 phosphorylation compared with HEK293 cells and nonneoplastic tissues. Inhibition of GSK3β resulted in attenuated cell survival and proliferation and increased apoptosis in most cancer cell lines and in HT-29 xenografts in rodents but not in HEK293 cells. GSK3β inhibition in colon cancer cells was associated with decreased hTERT expression and telomerase activity. Conclusion: The results indicate that deregulated GSK3β sustains gastrointestinal cancer cells survival through modulation of hTERT and telomerase.
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U2 - 10.1158/1078-0432.CCR-09-0973
DO - 10.1158/1078-0432.CCR-09-0973
M3 - Article
C2 - 19903789
AN - SCOPUS:72549086625
SN - 1078-0432
VL - 15
SP - 6810
EP - 6819
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 22
ER -