Aspirin inhibits proliferation of gemcitabine-resistant human pancreatic cancer cells and augments gemcitabine-induced cytotoxicity.
OBJECTIVE
To investigate whether aspirin is able to augment gemcitabine-induced cytotoxicity in human pancreatic cancer cells.


METHODS
Two gemcitabine-insensitive human pancreatic cancer cell lines, PANC-1 and Capan-1, were used. Cells were treated with either aspirin or gemcitabine alone or both of them. Cell growth and apoptosis were determined by MTT assay, Annexin V or Hoechest 33258 staining. Cell cycle distribution was examined by flow cytometry. Western blot with specific phosphorylated protein antibodies was used to detect the activation of protein kinase. RT-PCR and Western blot were applied to assess the transcription and protein level for cyclin D1 and Bcl-2.


RESULTS
Aspirin alone significantly inhibits the proliferation of PANC-1 cells by causing cell cycle arrest at G(1) phase. Aspirin potentiates the anti-survival effect of gemcitabine as well as its pro-apoptotic effect in PANC-1 cells, although aspirin per se does not trigger apoptosis. Aspirin inhibits GSK-3beta activation and suppresses the expression of its downstream gene products (cyclin D1 and Bcl-2), which are implicated in proliferation, survival and chemoresistance of pancreatic cancer. The effects of aspirin on Capan-1, were similar to that on PANC-1.


CONCLUSIONS
Our results suggest that aspirin inhibits the proliferation of gemcitabine-resistant pancreatic cancer cells and augments the antisurvival effect of gemcitabine, probably by suppressing the activity of GSK-3beta and its downstream gene products.
Ou
Yan-qiu
YQ
Department of Pharmacology, Zhong-shan Medical College, Sun Yat-Sen University, Guangzhou, China.
Zhu
Wen bo
Wb
Li
Yan
Y
Qiu
Peng-xin
PX
Huang
Yi-jun
YJ
Xie
Jun
J
He
Song-min
SM
Zheng
Xiao-ke
XK
Leng
Tian-dong
TD
Xu
Dong
D
Yan
Guang-mei
GM
D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001241:Aspirin / Q000494:pharmacology*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019938:Cyclin D1 / Q000187:drug effects / Q000235:genetics; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004357:Drug Synergism; D005434:Flow Cytometry; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000503:physiopathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000187:drug effects / Q000235:genetics; D000093542:Gemcitabine
D000964:Antimetabolites, Antineoplastic; D019253:Proto-Oncogene Proteins c-bcl-2; D003841:Deoxycytidine; D019938:Cyclin D1; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; D001241:Aspirin; D000093542:Gemcitabine