Hong-Wei Liang1, Nan Wang1, Yanbo Wang1, Feng Wang2, Zheng Fu1, Xin Yan3, Hao Zhu4, Wenli Diao1, Yitao Ding5, Xi Chen6, Chen-Yu Zhang7, Ke Zen8. 1. State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University Advanced Institute of Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University, Nanjing, Jiangsu 210093, China. 2. Department of General Surgery, the Affiliated Gulou Hospital of Nanjing University, Nanjing, Jiangsu 210093, China. 3. Comprehensive Cancer Center, the Affiliated Gulou Hospital of Nanjing University, Nanjing, Jiangsu 210093, China. 4. Department of Gastroenterology, the Affiliated Gulou Hospital of Nanjing University, Nanjing, Jiangsu 210093, China. 5. Department of Hepatobiliary Surgery, the Affiliated Gulou Hospital of Nanjing University, Nanjing, Jiangsu 210093, China. Electronic address: yitaoding@hotmail.com. 6. State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University Advanced Institute of Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University, Nanjing, Jiangsu 210093, China. Electronic address: xichen@nju.edu.cn. 7. State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University Advanced Institute of Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University, Nanjing, Jiangsu 210093, China. Electronic address: cyzhang@nju.edu.cn. 8. State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University Advanced Institute of Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University, Nanjing, Jiangsu 210093, China. Electronic address: kzen@nju.edu.cn.
Abstract
BACKGROUND & AIMS: Chronic hepatitis B virus (HBV) carriers have a high risk to develop hepatocellular carcinoma (HCC) but the underlying mechanism remains unclear. Recent studies suggest that viral-human hybrid RNA transcripts, which play a critical role in promoting HCC progression, may be the molecules responsible for the development of HCC in HBV infected patients. Here we determine whether HBx-LINE1, a hybrid RNA transcript of the human LINE1 and the HBV-encoded X gene generated in tumor cells of HBV-positive HCC, can serve as a molecular sponge for sequestering miR-122 and promoting liver cell abnormal mitosis and mouse hepatic injury. METHODS: Paired tumor and distal normal liver tissue specimens, as well as HBx-LINE1 overexpressing hepatic cells, were used to test the relationship between HBx-LINE1 and miR-122. Levels of HBx-LINE1 and miR-122 were assayed by qRT-PCR and Northern blot. HBx-LINE1-miR-122 binding was analyzed by luciferase reporter assay. Mouse hepatic injury was monitored by tissue staining and serum aspartate transaminase, alanine aminotransferase and total bilirubin measurement. RESULTS: HBx-LINE1 in HBV-positive HCC tissues was inversely correlated with miR-122. Each HBx-LINE1 consists of six miR-122-binding sites, and forced expression of HBx-LINE1 effectively depleted cellular miR-122, promoting hepatic cell epithelial-mesenchymal transition (EMT)-like changes, including β-catenin signaling activation, E-cadherin reduction and cell migration enhancement. Mice administered with HBx-LINE1 display a significant mouse liver cell abnormal mitosis and hepatic injury. However, all these effects of HBx-LINE1 are completely abolished by miR-122. CONCLUSIONS: Our finding illustrates a previously uncharacterized miR-122-sequestering mechanism by which HBx-LINE1 promotes hepatic cell EMT-like changes and mouse liver injury.
BACKGROUND & AIMS: Chronic hepatitis B virus (HBV) carriers have a high risk to develop hepatocellular carcinoma (HCC) but the underlying mechanism remains unclear. Recent studies suggest that viral-human hybrid RNA transcripts, which play a critical role in promoting HCC progression, may be the molecules responsible for the development of HCC in HBV infectedpatients. Here we determine whether HBx-LINE1, a hybrid RNA transcript of the human LINE1 and the HBV-encoded X gene generated in tumor cells of HBV-positive HCC, can serve as a molecular sponge for sequestering miR-122 and promoting liver cell abnormal mitosis and mousehepatic injury. METHODS: Paired tumor and distal normal liver tissue specimens, as well as HBx-LINE1 overexpressing hepatic cells, were used to test the relationship between HBx-LINE1 and miR-122. Levels of HBx-LINE1 and miR-122 were assayed by qRT-PCR and Northern blot. HBx-LINE1-miR-122 binding was analyzed by luciferase reporter assay. Mousehepatic injury was monitored by tissue staining and serum aspartate transaminase, alanine aminotransferase and total bilirubin measurement. RESULTS: HBx-LINE1 in HBV-positive HCC tissues was inversely correlated with miR-122. Each HBx-LINE1 consists of six miR-122-binding sites, and forced expression of HBx-LINE1 effectively depleted cellular miR-122, promoting hepatic cell epithelial-mesenchymal transition (EMT)-like changes, including β-catenin signaling activation, E-cadherin reduction and cell migration enhancement. Mice administered with HBx-LINE1 display a significant mouseliver cell abnormal mitosis and hepatic injury. However, all these effects of HBx-LINE1 are completely abolished by miR-122. CONCLUSIONS: Our finding illustrates a previously uncharacterized miR-122-sequestering mechanism by which HBx-LINE1 promotes hepatic cell EMT-like changes and mouseliver injury.
Authors: Joseph M Luna; Juan M Barajas; Kun-Yu Teng; Hui-Lung Sun; Michael J Moore; Charles M Rice; Robert B Darnell; Kalpana Ghoshal Journal: Mol Cell Date: 2017-07-20 Impact factor: 17.970