Liver Cancer
Copyright ©The Author(s) 2004. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 15, 2004; 10(4): 514-520
Published online Feb 15, 2004. doi: 10.3748/wjg.v10.i4.514
Inhibition of DNA primase and induction of apoptosis by 3,3’-diethyl-9-methylthia-carbocyanine iodide in hepatocellular carcinoma BEL-7402 cells
Zhi-Ming Li, Zong-Chao Liu, Zhong-Zhen Guan, Xiao-Feng Zhu, Jun-Min Zhou, Bing-Fen Xie, Gong-Kan Feng, Zhen-Yu Zhu, Wen-Qi Jiang
Zhi-Ming Li, Zong-Chao Liu, Zhong-Zhen Guan, Xiao-Feng Zhu, Jun-Min Zhou, Bing-Fen Xie, Gong-Kan Feng, Zhen-Yu Zhu, Wen-Qi Jiang, Cancer Hospital, Cancer Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
Author contributions: All authors contributed equally to the work.
Supported by the National High Technology Research and Development Program of China (863 Program), No. 2002AA2Z341C and the National Natural Science Foundation of China, No. 39870886
Correspondence to: Professor Wen-Qi Jiang, Cancer Hospital, Cancer Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China. wqjiang@yahoo.com
Telephone: +86-20-8734-3168 Fax: +86-20-8734-3392
Received: June 21, 2003
Revised: July 13, 2003
Accepted: August 25, 2003
Published online: February 15, 2004
Abstract

AIM: To evaluate the effects of 3,3’-diethyl-9-methylthia-carbocyanine iodide (DMTCCI) on DNA primase activity and on apoptosis of human hepatocellular carcinoma BEL-7402 cells.

METHODS: DNA primase assay was used to investigate DNA primase activity. MTT assay was applied to determine cell proliferation. Flow cytometric analysis, transmission electron microscopy, DNA fragmentation assay were performed to detect DMTCCI-induced apoptosis. Expression levels of p53, Bcl-2, Bcl-xL, Bad, Bax, survivin, Caspase-3 and poly (ADP-ribose) polymerase (PARP) were evaluated by immunoblot analysis. Caspase-3 activity was assessed with ApoAlert Caspase-3 colorimetric assay kit.

RESULTS: DMTCCI had inhibitory effects on eukaryotic DNA primase activity with IC50 value of 162.2 nmol/L. It also inhibited proliferation of human hepatocellular carcinoma BEL-7402 cells with IC50 value of 2.09 μmol/L. Furthermore, DMTCCI-induced BEL-7402 cell apoptosis was confirmed by DNA fragmentation (DNA ladders and sub-G1 formation) and transmission electron microscopy (apoptotic bodies formation). During the induction of apoptosis, expression of Bcl-2, Bcl-xL and survivin was decreased, and that of p53, Bad and Bax was increased. Caspase-3 was activated and poly (ADP-ribose) polymerase (PARP) was cleaved in BEL-7402 cells treated with DMTCCI.

CONCLUSION: The present data suggest that DMTCCI has inhibitory effects on eukaryotic DNA primase and can induce apoptosis of BEL-7402 cells. The modulation of expression of p53 and Bcl-2 family proteins, and activation of Caspase-3 might be involved in the induction of apoptosis.

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