Inducible and repressable oncogene-addicted hepatocellular carcinoma in Tet-on xmrk transgenic zebrafish

Li, Zhen; Huang, Xiaoqian; Zhan, Huiqing; Zeng, Zhiqiang; Li, Caixia; Spitsbergen, Jan M.; Meierjohann, Svenja; Schartl, Manfred; Gong, Zhiyuan

doi:10.1016/j.jhep.2011.07.025

« Previous Next »Journal of Hepatology
Volume 56, Issue 2 , Pages 419-425, February 2012

Inducible and repressable oncogene-addicted hepatocellular carcinoma in Tet-on xmrk transgenic zebrafish

Zhen Li
- Department of Biological Sciences, National University of Singapore, Singapore
Xiaoqian Huang
- Department of Biological Sciences, National University of Singapore, Singapore
Huiqing Zhan
- Department of Biological Sciences, National University of Singapore, Singapore
Zhiqiang Zeng
- Department of Biological Sciences, National University of Singapore, Singapore
Caixia Li
- Department of Biological Sciences, National University of Singapore, Singapore
Jan M. Spitsbergen
- Department of Microbiology and Marine and Freshwater Biomedical Sciences Center, Oregon State University, Corvallis, OR, USA
Svenja Meierjohann
- Physiologische Chemie I, Biocenter, University of Würzburg, Germany
Manfred Schartl
- Physiologische Chemie I, Biocenter, University of Würzburg, Germany
Zhiyuan Gong
- Department of Biological Sciences, National University of Singapore, Singapore
- Corresponding author. Address: Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore. Tel.: +65 65162860; fax: +65 67792486.

Received 25 February 2011; received in revised form 24 June 2011; accepted 16 July 2011. published online 02 September 2011.

Background & Aims

Liver cancer, mainly hepatocellular carcinoma, is a major malignancy and currently there are no effective treatment protocols due to insufficient understanding of hepatocarcinogenesis. As a potentially high-throughput and cost-effective experimental model, the zebrafish is increasingly recognized for disease studies. Here, we aim at using the zebrafish to generate a convenient hepatocellular carcinoma model.

Methods

Using the Tet-on system for liver-specific expression of fish oncogene xmrk, a hyperactive version of epidermal growth factor receptor homolog, we have generated transgenic zebrafish with inducible development of liver cancer.

Results

Liver tumors were rapidly induced with 100% penetrance in both juvenile and adult xmrk transgenic fish. Histological examination indicated that they all showed features of hepatocellular carcinoma. The induced liver tumors regressed rapidly upon inducer withdrawal. During the tumor induction stage, we detected increased cell proliferation and activation of Xmrk downstream targets Erk and Stat5, which were important for liver tumorigenesis as proved by inhibition experiments. When tumors regressed, there were decreased phosphorylated Erk and Stat5 accompanied with an increase in apoptosis.

Conclusions

Our zebrafish model demonstrates the potential of a hyperactivated epidermal growth factor receptor pathway in initiating heptocarcinogenesis. It provides clear evidence for the requirement of only a single oncogene for HCC initiation and maintenance and is thus a convenient model for further investigation of oncogene addiction and future anti-cancer drug screening.

Abbreviations: HCC, hepatocellular carcinoma, TRE, tetracycline responsive element, EGFR, epidermal growth factor receptor, GFP, green fluorescent protein, RT-PCR, reverse transcriptase-polymerisation chain reaction, WISH, whole-mount in situ hybridization, H&E, hematoxylin and eosin, hpf, hour postfertilization, wpt, week post treatment-initiation, mpf, month postfertilization, HCA, hepatocellular adenoma