Original Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jun 21, 2012; 18(23): 2938-2947
Published online Jun 21, 2012. doi: 10.3748/wjg.v18.i23.2938
Hepatocellular carcinoma and macrophage interaction induced tumor immunosuppression via Treg requires TLR4 signaling
Jing Yang, Jin-Xiang Zhang, Hui Wang, Guo-Liang Wang, Qing-Gang Hu, Qi-Chang Zheng
Jing Yang, Qing-Gang Hu, Qi-Chang Zheng, Department of Hepatobiliary Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China
Jin-Xiang Zhang, Guo-Liang Wang, Department of Emergency Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China
Hui Wang, Department of Medical Genetics, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
Author contributions: Yang J, Zhang JX and Wang GL performed the majority of experiments; Zhang JX, Wang H and Zheng QC provided vital reagents and analytical tools and revised the manuscript; Yang J and Hu QG collected the human materials and provided financial support for this work; Yang J designed the study and wrote the manuscript.
Correspondence to: Qi-Chang Zheng, Professor, Department of Hepatobiliary Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China. qc_zheng@mail.hust.edu.cn
Telephone: +86-27-62900023 Fax: +86-27-62900023
Received: May 13, 2011
Revised: March 26, 2012
Accepted: April 2, 2012
Published online: June 21, 2012
Abstract

AIM: To investigated the interaction between toll-like receptor 4 (TLR4)-activated hepatoma cells and macrophages in the induction of tumor-immune suppression mediated by CD4+CD25high family of transcription factor P3 (FOXP3) regulatory T cells (Tregs).

METHODS: The proportion of FOXP3+ Tregs was identified in peripheral blood and tumor tissues of 60 hepatocellular carcinoma (HCC) patients. TLR4 expression was examined in tumor tissues and cell lines. The correlation was examined between FOXP3+ Tregs in peripheral blood and TLR4 expression of HCC tissues. Following activation of TLR4 in H22 murine hepatoma cells pre-incubated with lipopolysaccharide (LPS) and co-cultured with macrophage cell line RAW246.7, the synthesis of cytokines tumor necrosis factor-α, CCL22, and interleukin (IL)-10 by the two cell lines was detected and analyzed.

RESULTS: FOXP3+ Tregs were enriched in tumor sites, and circulating FOXP3+ Tregs were increased in HCC patients in correlation with multiple tumor foci and up-regulated TLR4 expression in HCC tissues. Semi-quantitative analysis indicated that TLR4 was over-expressed in HCC compared with the matched normal tissues. Cell cultivation experiments indicated that the mRNAs of IL-10 and CCL22 were significantly up-regulated in the RAW246.7 cell line when co-cultured with LPS pre-incubated H22 cells.

CONCLUSION: In hepatoma cell lines, TLR4 may indirectly facilitate the recruitment of Tregs to the tumor site and promote intrahepatic metastasis through its interaction with macrophages.

Keywords: CD4+CD25highFOXP3+ regulatory T cell; Toll-like receptor; Tumor immunity; Hepatocellular carcinoma; Macrophage