Original Article
Copyright ©2010 Baishideng. All rights reserved.
World J Gastroenterol. May 21, 2010; 16(19): 2371-2377
Published online May 21, 2010. doi: 10.3748/wjg.v16.i19.2371
Effect of 5-Aza-2’-deoxycytidine on immune-associated proteins in exosomes from hepatoma
Wen-Hua Xiao, Gao-Wa Sanren, Jian-Hua Zhu, Qiu-Wen Li, Huan-Rong Kang, Ru-Liang Wang, Lin-Ping Song, Ming Ye
Wen-Hua Xiao, Jian-Hua Zhu, Qiu-Wen Li, Huan-Rong Kang, Ru-Liang Wang, Lin-Ping Song, Ming Ye, Department of Oncology, First Affiliated Hospital, Chinese PLA General Hospital, Beijing 100048, China
Gao-Wa Sanren, Department of Histology and Embryology, Inner Mongolia Medical College, Hohhot 010010, Inner Mongolia Autonomous Region, China
Author contributions: Xiao WH and Sanren GW contributed equally to this work; Xiao WH and Zhu JH designed the research; Xiao WH, Sanren GW, Li QW and Kang HR performed the research; Wang RL, Song LP and Ye M analyzed the data; Xiao WH and Sanren GW wrote the paper.
Supported by Capital Medical Development Scientific Research Fund, No. 2005-3086
Correspondence to: Wen-Hua Xiao, MD, PhD, Professor, Department of Oncology, First Affiliated Hospital, Chinese PLA General Hospital, Beijing 100048, China. w_hxiao@hotmail.com
Telephone: +86-10-66867329 Fax: +86-10-66867329
Received: November 4, 2009
Revised: February 1, 2010
Accepted: February 8, 2010
Published online: May 21, 2010
Abstract

AIM: To study the effect of 5-Aza-2’-deoxycytidine (5-Aza-CdR) on heat shock protein 70 (HSP70), human leucocyte antigen-I (HLA-I) and NY-ESO-1 proteins in exosomes produced by hepatoma cells, HepG2 and Hep3B.

METHODS: Exosomes derived from HepG2 and Hep3B cells treated with or without 5-aza-CdR were isolated and purified by ultrafiltration centrifugation and sucrose gradient ultracentrifugation. The number of exosomes was counted under electron microscope. Concentration of proteins in exosomes was measured by bicinchoninic acid protein assay. Expression of HSP70, HLA-I and NY-ESO-1 proteins in exosomes was detected by Western blotting and immunoelectron microscopy. mRNA expression of p53 gene was detected by reverse transcription polymerase chain reaction.

RESULTS: The mRNA expression of p53 gene was increased in both hepatoma cell lines after treatment with 5-Aza-CdR. The number of exosomes and the concentration of total proteins in exosomes were increased significantly after treatment with 5-aza-CdR (P < 0.05). After treatment with 5-Aza-CdR, immunoelectron microscopy and Western blotting showed that the HSP70, HLA-I and NY-ESO-1 proteins were increased in exosomes produced by both hepatoma cell lines.

CONCLUSION: 5-aza-CdR, an inhibitor of DNA methyltransferase, can increase exosomes produced by hepatoma cells and immune-associated protein component of exosomes, which may be mediated by p53 gene up-regulation and 5-Aza-CdR demethylation.

Keywords: 5-Aza-2’-deoxycytidine; Exosome; Immunomolecule; Hepatoma cell