Liver Cancer
Copyright ©The Author(s) 2004. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 15, 2004; 10(2): 205-208
Published online Jan 15, 2004. doi: 10.3748/wjg.v10.i2.205
Enhancement of osteopontin expression in HepG2 cells by epidermal growth factor via phosphatidylinositol 3-kinase signaling pathway
Guo-Xin Zhang, Zhi-Quan Zhao, Hong-Di Wang, Bo Hao
Guo-Xin Zhang, Zhi-Quan Zhao, Hong-Di Wang, Bo Hao, Department of Gastroenterology, the First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
Author contributions: All authors contributed equally to the work.
Correspondence to: Dr. Guo-Xin Zhang, 300 Guangzhou Road, Department of Gastroenterology, the First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China. guoxinz2002@yahoo.com
Telephone: +86-25-3718836 Fax: +86-25-3724440
Received: June 21, 2003
Revised: August 8, 2003
Accepted: August 16, 2003
Published online: January 15, 2004
Abstract

AIM: Osteopontin (OPN) is a phosphorylated glycoprotein with diverse functions including cancer development, progression and metastasis. It is unclear how osteopontin is regulated in HepG2 cells. The aim of this study was to investigate the effect of epidermal growth factor on the expression of osteopontin in HepG2 cells, and to explore the signal transduction pathway mediated this expression.

METHODS: Osteopontin expression was detected by RNAase protection assay and Western blot. Wortmannin, a specific inhibitor of PI3K, was used to see if PI3K signal transduction was involved in the induction of osteopontin gene expression.

RESULTS: HepG2 cells constitutively expressed low levels of osteopontin. Treatment with epidermal growth factor increased osteopontin mRNA and protein level in a dose-and time-dependent manner. Application of wortmannin caused a dramatic reduction of epidermal growth factor-induced osteopontin expression.

CONCLUSION: Osteopontin gene expression can be induced by treatment of HepG2 cells with epidermal growth factor. Epidermal growth factor may regulate osteopontin gene expression through PI3K signaling pathway. Several potential targets in the pathway can be manipulated to block the synthesis of osteopontin and inhibit liver cancer metastasis.

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