Gastric Cancer
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jan 7, 2006; 12(1): 29-35
Published online Jan 7, 2006. doi: 10.3748/wjg.v12.i1.29
Inhibitory effect of Polo-like kinase 1 depletion on mitosis and apoptosis of gastric cancer cells
Xue-Hua Chen, Bin Lan, Ying Qu, Xiao-Qing Zhang, Qu Cai, Bing-Ya Liu, Zheng-Gang Zhu
Xue-Hua Chen, Ying Qu, Xiao-Qing Zhang, Qu Cai, Bing-Ya Liu, Zheng-Gang Zhu, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Medical School of Shanghai Jiao Tong University, Shanghai 200025, China
Bin Lan, Department of Surgical Oncology, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
Co-first-authors: Xue-Hua Chen and Bin Lan
Co-correspondents: Bing-Ya Liu and Zheng-Gang Zhu
Supported by the Major State Basic Research Development Program of China, 973 program, No. 2002CB713700
Correspondence to: Dr Bing-Ya Liu Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Medical School of Shanghai Jiao Tong University, Shanghai 200025 China. liubysh@yahoo.com
Telephone: +86-21-64674654 Fax: +86-21-64373909
Received: May 13, 2005
Revised: May 28, 2005
Accepted: June 11, 2005
Published online: January 7, 2006
Abstract

AIM: Polo-like kinase 1 (PLK1) serine/threonine kinase plays a vital role in multiple phases of mitosis in gastric cancer cells. To investigate the effect of PLK1 depletion on mitosis and apoptosis of gastric cancer cells.

METHODS: PLK1 expression was blocked by small RNA interference(siRNA). The expression levels of PLK1, cdc2, cyclin B and caspase 3 were detected by Western blotting. Then, PLK1 depletion, cdc2 activity, cell proliferation, cell cycle phase distribution, mitotic spindle structure, and the rate of apoptosis of the PLK1 knockdown cells were observed.

RESULTS: PLK1 gene knockdown was associated with increased cyclin B expression, increased cdc2 activity (but not with the expression levels), accumulation of gastric cancer cells at G2/M, improper mitotic spindle formation, delayed chromosome separation and delayed or arrested cytokinesis. Moreover, PLK1 depletion in gastric cancer cells was associated with decreased proliferation, attenuated pro-caspase 3 levels and increased apoptosis.

CONCLUSION: Blockage of PLK1 expression may lead to decreased mitosis or even apoptosis in gastric cancer cells, indicating that PLK1 may be a valuable therapeutic target for gastric cancer.

Keywords: Gastric cancer cells; PLK1 gene; Mitosis; Cell cycle; Apoptosis