RT Journal Article
SR Electronic
T1 Enhanced Expression of Asparagine Synthetase under Glucose-Deprived Conditions Protects Pancreatic Cancer Cells from Apoptosis Induced by Glucose Deprivation and Cisplatin
JF Cancer Research
JO Cancer Res
FD American Association for Cancer Research
SP 3345
OP 3355
DO 10.1158/0008-5472.CAN-06-2519
VO 67
IS 7
A1 Cui, Hongyan
A1 Darmanin, Stephanie
A1 Natsuisaka, Mitsuteru
A1 Kondo, Takeshi
A1 Asaka, Masahiro
A1 Shindoh, Masanobu
A1 Higashino, Fumihiro
A1 Hamuro, Junji
A1 Okada, Futoshi
A1 Kobayashi, Masataka
A1 Nakagawa, Koji
A1 Koide, Hideyuki
A1 Kobayashi, Masanobu
YR 2007
UL http://cancerres.aacrjournals.org/content/67/7/3345.abstract
AB Although hypovasculature is an outstanding characteristic of pancreatic cancers, the tumor cells survive and proliferate under severe hypoxic, glucose-deprived conditions caused by low blood supply. It is well known that the hypoxia-inducible factor-1 pathway is essential for the survival of pancreatic cancer cells under hypoxic conditions. To discover how pancreatic cancer cells adapt to glucose deprivation as well as hypoxia, we sought glucose deprivation–inducible genes by means of a DNA microarray system. We identified 63 genes whose expression was enhanced under glucose-deprived conditions at >2-fold higher levels than under normal glucose conditions. Among these genes, asparagine synthetase (ASNS) was studied in detail. Although it is known to be associated with drug resistance in leukemia and oncogenesis triggered by mutated p53, its function is yet to be determined. In this study, we found that glucose deprivation induced the overexpression of ASNS through an AMP-activated protein kinase–independent and activating transcription factor-4–dependent manner and that ASNS protects pancreatic cancer cells from apoptosis induced by glucose deprivation itself. ASNS overexpression also induced resistance to apoptosis triggered by cisplatin [cis-diammine-dichloroplatinum (CDDP)] and carboplatin, but not by 5-fluorouracil, paclitaxel, etoposide, or gemcitabine. We show that glucose deprivation induces the activation of c-jun NH2-terminal kinase (JNK)/stress-activated protein kinase (SAPK) in a mock transfectant but not in an ASNS transfectant. Consequently, an inhibitor of JNK/SAPK decreased the sensitivity of pancreatic cancer cells to apoptosis by glucose deprivation and CDDP. These results strongly suggest that ASNS is induced by glucose deprivation and may play a pivotal role in the survival of pancreatic cancer cells under glucose-deprived conditions. [Cancer Res 2007;67(7):3345–55] ©2007 American Association for Cancer Research.