Liver Cancer
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Dec 28, 2008; 14(48): 7321-7328
Published online Dec 28, 2008. doi: 10.3748/wjg.14.7321
Scutellaria barbate extract induces apoptosis of hepatoma H22 cells via the mitochondrial pathway involving caspase-3
Zhi-Jun Dai, Xi-Jing Wang, Zong-Fang Li, Zong-Zheng Ji, Hong-Tao Ren, Wei Tang, Xiao-Xu Liu, Hua-Feng Kang, Hai-Tao Guan, Ling-Qin Song
Zhi-Jun Dai, Xi-Jing Wang, Hong-Tao Ren, Xiao-Xu Liu, Hua-Feng Kang, Hai-Tao Guan, Ling-Qin Song, Department of Oncology, the Second Affiliated Hospital, Medical School of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
Zong-Fang Li, Zong-Zheng Ji, Department of General Surgery, the Second Affiliated Hospital, Medical School of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
Wei Tang, Department of life Science, Shaanxi Normal Uni-versity, Xi’an 710061, Shaanxi Province, China
Author contributions: Dai ZJ and Wang XJ designed the research; Dai ZJ, Li ZF, Ren HT, Tang W and Song LQ performed the research; Li ZF, Ji ZZ, Liu XX and Kang HF contributed to the reagents, materials, analysis; Dai ZJ and Guan HT analyzed the data; Dai ZJ and Ren HT wrote the paper.
Supported by The Science and Technology Foundation of Shaanxi Province, China, No. 2006K16-G5(1) and Sci-tech Program of Xi’an City, China, No. YF07175
Correspondence to: Dr. Zhi-Jun Dai, Department of Oncology, the Second Affiliated Hospital, Medical School of Xi’an Jiaotong University, No. 157, West 5th Road, Xi’an 710004, Shaanxi Province, China.
Telephone: +86-29-87679526 Fax: +86-29-87679282
Received: October 13, 2008
Revised: November 24, 2008
Accepted: December 1, 2008
Published online: December 28, 2008

AIM: To study the growth inhibitory and apoptotic effects of Scutellaria barbata D.Don (S. barbata) and to determine the underlying mechanism of its antitumor activity in mouse liver cancer cell line H22.

METHODS: Proliferation of H22 cells was examined by MTT assay. Cellular morphology of PC-2 cells was observed under fluorescence microscope and transmission electron microscope (EM). Mitochondrial transmembrane potential was determined under laser scanning confocal microscope (LSCM) with rhodamine 123 staining. Flow cytometry was performed to analyze the cell cycle of H22 cells with propidium iodide staining. Protein level of cytochrome C and caspase-3 was measured by semi-quantitive RT-PCR and Western blot analysis. Activity of caspase-3 enzyme was measured by spectrofluorometry.

RESULTS: MTT assay showed that extracts from S. barbata (ESB) could inhibit the proliferation of H22 cells in a time-dependent manner. Among the various phases of cell cycle, the percentage of cells in S phase was significantly decreased, while the percentage of cells in G1 phase was increased. Flow cytometry assay also showed that ESB had a positive effect on apoptosis. Typical apoptotic morphologies such as condensation and fragmentation of nuclei and blebbing membrane of apoptotic cells could be observed under transmission electron microscope and fluorescence microscope. To further investige the molecular mechanism behind ESB-induced apoptosis, ESB-treated cells rapidly lost their mitochondrial transmembrane potential, released mitochondrial cytochrome C into cytosol, and induced caspase-3 activity in a dose-dependent manner.

CONCLUSION: ESB can effectively inhibit the proliferation and induce apoptosis of H22 cells involving loss of mitochondrial transmembrane potential, release of cytochrome C, and activation of caspase-3.

Keywords: Scutellaria barbate, Hepatoma, Apoptosis, Mitochondrial transmembrane potential, Serum pharmacology