Issue title: Free Radicals in Biology and Medicine: From
Inflammation to Biotechnology
Article type: Research Article
Authors: Park, Jung-Ran | Park, Joon-Suk | Jo, Eun-Hye | Hwang, Jae-Woong | Kim, Sun-Jung | Ra, Jeong-Chan | Aruoma, Okezie I. | Lee, Yong-Soon | Kang, Kyung-Sun
Affiliations: Laboratory of Stem Cell and Tumor Biology, Department
of Veterinary Public Health, College of Veterinary Medicine and BK 21 Program
for Veterinary Science, Seoul National University, Seoul 151-742, South
Korea | Faculty of Health and Social Care, London South Bank
University, 103 Borough Road, London, SE1 0AA, UK | RNL BIO, Co., Ltd., Central Research Institute, 2F,
Sungmoon B/D, 1-26, Yangjae-dong, Seocho-gu, Seoul 137-886, South Korea
Note: [] Address for correspondence: Professor Kyung-Sun Kang, Ph. D.,
DVM, Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public
Health, College of Veterinary Medicine, Seoul National University, Sillim
9-dong, Gwanak-gu, Seoul 151-742, South Korea. Tel.: +82 2 880 1246; Fax: +82 2
876 7610; E-mail: kangpub@snu.ac.kr
Abstract: Chaga mushroom (Inonotus obliquus) has continued to receive
attention as a folk medicine with indications for the treatment of cancers and
digestive diseases. The anticarcinogenic effect of Chaga mushroom extract was
investigated using a model system of gap junctional intercellular communication
(GJIC) in WB-F344 normal rat liver epithelial cells. The cells were
pre-incubated with Chaga mushroom extracts (5, 10, 20 μg/ml) for 24 h and
this was followed by co-treatment with Chaga mushroom extracts and TPA
(12-O-tetradecanoylphorbol-13-acetate, 10 ng/ml) for 1 h. The inhibition of
GJIC by TPA (12-O-tetradecanoylphorbol-13-acetate), promoter of cancer, was
prevented with treatment of Chaga mushroom extracts. Similarly, the increased
phosphorylated ERK1/2 and p38 protein kinases were markedly reduced in Chaga
mushroom extracts-treated cells. There was no change in the JNK kinase protein
level, suggesting that Chaga mushroom extracts could only block the activation
of ERK1/2 and p38 MAP kinase. The Chaga mushroom extracts further prevented the
inhibition of GJIC through the blocking of Cx43 phosphorylation. Indeed
cell-to-cell communication through gap junctional channels is a critical factor
in the life and death balance of cells because GJIC has an important function
in maintaining tissue homeostasis through the regulation of cell growth,
differentiation, apoptosis and adaptive functions of differentiated cells. Thus
Chaga mushroom may act as a natural anticancer product by preventing the
inhibition of GJIC through the inactivation of ERK1/2 and p38 MAP kinase.
Keywords: Inonotus obliquus (Chaga mushroom), gap junctional intercellular communication, connexin 43, ERK 1/2, p38 MAP kinase, chemoprevention and signaling mechanisms
Journal: BioFactors, vol. 27, no. 1-4, pp. 147-155, 2006
Received 15 January 2006
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Accepted 22 March 2006
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Published: 2006
