Basic Research
Copyright ©The Author(s) 2003. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 15, 2003; 9(12): 2745-2750
Published online Dec 15, 2003. doi: 10.3748/wjg.v9.i12.2745
Oil A induces apoptosis of pancreatic cancer cells via caspase activation, redistribution of cell cycle and GADD expression
Mi-Lian Dong, Yue-Chun Zhu, John V. Hopkins
Mi-Lian Dong, Affiliated Taizhou Hospital, Wenzhou Medical College, Linhai 317000, Zhejiang, Provice China
Yue-Chun Zhu, John V. Hopkins, Northwestern University Medical School, Chicago, IL60611-3008, U.S.A
Author contributions: All authors contributed equally to the work.
Supported by the National Cancer Institute of USA, No. CA72712, and Special Funds for Zhejiang 151 Talent Project of China, No. 98-2095
Correspondence to: Dr Mi-Lian Dong, Taizhou Hospital of Wenzhou Medical College, 150 Ximen Street, Linhai 317000, Zhejiang, Provice China. mdong2@hotmail.com
Telephone: +86-576-5315829 Fax: +86-576-5315829
Received: August 23, 2003
Revised: August 29, 2003
Accepted: September 10, 2003
Published online: December 15, 2003
Abstract

AIM: To explore the mechanisms of effects of oil A on apoptosis of human pancreatic cancer cells.

METHODS: Cellular DNA content was analyzed by flow cytometry. Western blotting was used for caspase-3 and PARP, caspase-7, caspase-9, cytochrome c, Bcl-2, Bax, Mcl-1, cyclinA, cyclin B1, cyclin D1, cyclin E, CDK2, CDK4, CDK6, P21, P27,GADD45, GADD153.

RESULTS: The caspase-3, caspase-7, and caspase-9 activities were significantly increased as well as the cleavage of caspase-3, downstream substrate poly-ADP ribose polymerase (PARP) was induced. The amount of cytochrome c in the cytosolic fraction was increased, while the amount of cytochrome c in the mitochondrial fraction was decreased after oil A treatment. The anti-apoptosis proteins Bcl-2 and Mcl-1 were decreased in parallel and Bax increased, indicating that Bcl-2 family proteins-mitochondria-caspase cascade was responsible for oil-induced apoptosis. The proportion of cells in the G0/G1 decreased in MiaPaCa-2 and AsPC-1 cells after the treatment of oil A for 24 hours. The number of cells in S phase was increased in two cancer cell lines at 24 hours. Therefore, cells were significantly accumulated in G2/M phase. The cells with a sub-G0/G1 DNA content, a hallmark of apoptosis, were seen at 24 hours both in MiaPaCa-2 and AsPC-1 cells following exposure to oil A. The expression of cyclin A and cyclin B1 was slightly decreased and cyclin D1 levels were markedly lowered in MiaPaCa-2 cells. The expression of cyclin A and cyclin B1 was markedly decreased and cyclin D1 levels were slightly lowered in AsPC-1 cells, while cyclin E was not affected and the levels of CDK2, CDK4, and CDK6 were unchanged in MiaPaCa-2 and AsPC-1 cells. In response to oil A, P21 expression was increased, but P27 expression was not affected. The expression of both GADD45 and GADD153 was increased in two cell lines following oil A treatment.

CONCLUSION: Oil A induces apoptosis of pancreatic cancer cells via activating caspase cascade, modifying cell cycle progress and changing cell cycle-regulating proteins and GADD expression.

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