J. Cancer Mol. 2: 117-122, 2006

[Research Paper]

RASSF2 Induces Activated Ras-Dependent Cell Growth Inhibition and Apoptosis in Human Pancreatic Cancer Cells

Jing-Hua Ren, Ju-Sheng Lin, Wen-Shan He, Xue-Mei Sun, Pei-Yuan Li, Ying Chang, Yao Liu, Chao Li, and Xin-Sheng Gao

Institute of Liver Diseases, Tongji Hospital [J.-H. Ren, J.-S. Lin, X.-M. Sun, P.-Y. Li, Y. Chang, Y. Liu, C. Li, X.-S. Gao] and Department of General Surgery, Union Hospital [W.-S. He], Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, P. R. of China 

Abstract:

AIM: Activated Ras mediates both cell death and cell survival by distinct effector pathways.  It is now apparent that some of the growth-inhibitory properties of Ras are mediated via the RASSF (Ras-Association Domain Family) members.  To date, there are five members of this family have been identified (Nore1, RASSF1, RASSF2, RASSF3, and RASSF4).  Among them, RASSF2 is a novel K-Ras specific effector and potential tumor suppressor.  In this study, we aimed to investigate the growth-antagonistic status of RASSF2 in three pancreatic cancer cell lines and the correlation of its tumor-suppressive effect with K-ras mutations.

METHODS: The RASSF2 gene fragment was amplified by RT-PCR from normal human peripheral blood mononuclear cells and cloned into the eukaryotic expressing vector pEGFP-C1 by DNA recombination techniques.  The eukaryotic expression plasmid of RASSF2 was then transfected into three pancreatic cancer cell lines (BxPC-3, AsPc-1 and PANC-1).  Among these three cell lines, both AsPc-1 and PANC-1 have K-ras point mutations, while there is no mutation of K-ras in BxPC-3.  We then analysed the growth inhibition of these cells by MTT, and apoptosis of them by flow cytometry and TUNEL assays.

RESULTS: We have successfully constructed the eukaryotic expressing plasmid pRASSF2.  The cell growth inhibition and apoptosis induced by RASSF2 were markedly higher than those of control groups.  Moreover, we showed that pancreatic cancer cells haboring K-ras mutations were prone to apoptosis when they acquired RASSF2.

CONCLUSION: The Ras effector RASSF2 is a novel tumor suppressor in human pancreatic cancer and the study may give us some clues as to gene therapy of pancreatic cancer by using RASSF2. 

Received 5/17/06; Revised 6/7/06; Accepted 6/8/06.

¹Correspondence: Dr. Ju-Sheng Lin, Institute of Liver Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China. Phone: 86-27-8366 2578. E-mail: jslin@tjh.tjmu.edu.cn

²Abbreviations: RASSF, Ras-Association Domain Family; RA domain, Ras-association domain; MTT, microculture tetrozolium test; TUNEL, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling.