Original Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jun 21, 2012; 18(23): 2956-2965
Published online Jun 21, 2012. doi: 10.3748/wjg.v18.i23.2956
Targeting X-linked inhibitor of apoptosis protein inhibits pancreatic cancer cell growth through p-Akt depletion
Chun Jiang, Xiao-Ping Yi, Hong Shen, Yi-Xiong Li
Chun Jiang, Department of Gynaecology and Obstetrics, Xiang Ya Hospital, Central South University, Changsha 410008, Hunan Province, China
Xiao-Ping Yi, Department of Radiology, Xiang Ya Hospital, Central South University, Changsha 410008, Hunan Province, China
Hong Shen, Medical Research Center, Xiang Ya Hospital, Central South University, Changsha 410008, Hunan Province, China
Yi-Xiong Li, Department of General Surgery, Xiang Ya Hospital, Central South University, Changsha 410008, Hunan Province, China
Author contributions: Jiang C and Yi XP performed the majority of the experiments; Shen H provided analytical tools and was also involved in editing the manuscript; Li YX provided financial support for this work and designed the study; Jiang C wrote the manuscript.
Supported by National Natural Science Foundation of China, No. 30872492; and Natural Science Foundation of Hunan Province, No. 088JJ3042
Correspondence to: Dr. Yi-Xiong Li, Department of General Surgery, Xiang Ya Hospital, Central South University, 87 Xiang Ya Road, Changsha 410008, Hunan Province, China. liyixiong2011@hotmail.com
Telephone: +86-731-84327021 Fax: +86-731-84327332
Received: October 17, 2011
Revised: April 5, 2012
Accepted: April 10, 2012
Published online: June 21, 2012
Abstract

AIM: To determine whether lentivirus-mediated shRNA targeting the X-linked inhibitor of apoptosis protein (XIAP) gene could be exploited in the treatment of pancreatic cancer.

METHODS: Human pancreatic cancer cells Panc-1, Mia-paca2, Bxpc-3 and SW1990, infected with lentivirus, were analyzed by real-time polymerase chain reaction (PCR). Western blotting was used to examine XIAP protein levels, survivin and p-Akt to confirm the result of real-time PCR and determine the possible mechanism. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure IC50 to determine chemosensitivity to the chemotherapeutic drugs 5-fluorouracil (5-FU) and gemcitabine. A colony assay, MTT assay and a tumorigenicity experiment were used to study cell proliferation in vitro and in vivo. Caspase-3/7 activity, 4',6-diamidino-2-phenylindole-staining and flow cytometric measurements were used to study apoptosis in SW1990 cells.

RESULTS: XIAP proteins were found to be differentially expressed among pancreatic cancer cell lines Panc-1, Mia-paca2, Bxpc-3 and SW1990. Data of real-time PCR and Western blotting showed that XIAP was reduced persistently and markedly by lentivirus-mediated shRNA. Downregulation of XIAP by transfection with XIAP shRNA resulted in decreased p-Akt expression. XIAP shRNA also inhibited the growth of pancreatic cancer cells in vitro and in vivo, enhanced drug-induced apoptosis and increased chemosensitivity to 5-FU and gemcitabine. Results also suggest that inhibition of XIAP and subsequent p-Akt depletion may have an anti-tumor effect through attenuating the ability of cancer cells to survive.

CONCLUSION: Lentivirus-mediated gene therapy is an attractive strategy in the treatment of pancreatic cancer and justifies the use of lentivirus in pancreatic cancer gene therapy studies.

Keywords: Pancreatic cancer; Lentivirus-mediated shRNA; X-linked inhibitor of apoptosis protein; p-Akt; Gene therapy; Proliferation; Apoptosis