Gradually elevated expression of Gankyrin during human hepatocarcinogenesis and its clinicopathological significance.

Hongbiao Jing,Haiying Mo,Qingda Meng,Guoming Zhang,Lingsheng Meng,Yanhong Tai

doi:10.1038/srep05503

Hongbiao Jing, Haiying Mo + Show 4 more

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https://doi.org/10.1038/srep05503

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Abstract

Gankyrin is an important oncoprotein that is overexpressed in human hepatocellular carcinoma (HCC). However, the gradual alteration of Gankyrin in successive stages during human HCC development and the mechanism of Gankyrin-mediated hepatocarcinogenesis remain largely unknown. In this study, we evaluated the pattern and level of Gankyrin protein expression using immunohistochemistry in various liver tissues, including normal liver, chronic hepatitis, cirrhosis, adenomatous hyperplasia (AH), and HCC tissues, to analyze its clinicopathological significance. Furthermore, we stably transfected the shRNA-Gan vector, which targets human Gankyrin, into HepG2 cells to assess the role of Gankyrin in cell proliferation and tumorigenicity. The expression level of Gankyrin in the cytoplasm, nucleus, and whole cell was gradually elevated during consecutive stages of hepatocarcinogenesis. The nuclear Gankyrin level in AH was significantly higher than that in normal liver, chronic hepatitis, and cirrhotic tissues. The cytoplasmic, nuclear, and total cellular Gankyrin expression levels in HCC were significantly correlated with capsular invasion and intrahepatic metastasis. Silencing Gankyrin expression using shRNA-Gan repressed tumor cell proliferation, tumorigenicity, migration, and invasion in vitro. Our findings demonstrate that Gankyrin is aberrantly expressed beginning at the initiation stage and plays an important role in the initiation, promotion, and progression of hepatocarcinogenesis.

Highlights

Gankyrin is an important oncoprotein that is overexpressed in human hepatocellular carcinoma (HCC)
HCC develops in a well-defined multistep process, from normal liver to chronic hepatitis, cirrhosis, adenomatous hyperplasia (AH), and to HCC2,3
In the wellestablished rat model of HCC induced by diethylnitrosamine (DEN) and other chemicals, it was shown that Gankyrin overexpression, pRb degradation, and the hypermethylation of CDKN2A and TP53 are the initiating events that promote the multistep process of hepatocarcinogenesis[14,16,19]

Summary

Introduction

Gankyrin is an important oncoprotein that is overexpressed in human hepatocellular carcinoma (HCC). External factors that contribute to HCC development are infection by hepatitis B or C, chronic alcohol intake, exposure to aflatoxin, and chronic liver disease of any type These factors can lead to cirrhosis and adenomatous hyperplasia (AH), culminating in HCC with possible metastatic disease[4]. This multistep hepatocellular carcinogenesis model has been well established histopathologically and clinically, the molecular mechanisms at each stage (chronically diseased liver, cirrhosis, AH, and HCC) remain elusive. To evaluate the role of Gankyrin in HCC development and analyze its clinicopathological significance, we examined the level and pattern of Gankyrin protein expression in various liver tissues at each stage of the multistep process of human hepatocarcinogenesis using immunohistochemistry (IHC). To evaluate www.nature.com/scientificreports the effects of Gankyrin downregulation on tumor biological behavior, we used a plasmid vector to express a short-hairpin RNA (shRNA) targeted against Gankyrin mRNA in HepG2 human HCC cells (ATCC, Rockville, MD)

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