Atsuyuki Ikeda1, Takahiro Shimizu1, Yuko Matsumoto1, Yosuke Fujii1, Yuji Eso1, Tadashi Inuzuka1, Aya Mizuguchi1, Kazuharu Shimizu2, Etsuro Hatano3, Shinji Uemoto3, Tsutomu Chiba1, Hiroyuki Marusawa4. 1. Department of Gastroenterology and Hepatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 2. Department of Nanobio Drug Discovery, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan. 3. Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 4. Department of Gastroenterology and Hepatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan. Electronic address: maru@kuhp.kyoto-u.ac.jp.
Abstract
BACKGROUND & AIMS: Hepatocellular carcinoma develops in patients with chronic hepatitis or cirrhosis via a stepwise accumulation of various genetic alterations. To explore the genetic basis of development of hepatocellular carcinoma in hepatitis C virus (HCV)-associated chronic liver disease, we evaluated genetic variants that accumulate in nontumor cirrhotic liver. METHODS: We determined the whole exome sequences of 7 tumors and background cirrhotic liver tissues from 4 patients with HCV infection. We then performed additional sequencing of selected exomes of mutated genes, identified by whole exome sequencing, and of representative tumor-related genes on samples from 22 cirrhotic livers with HCV infection. We performed in vitro and in vivo functional studies for one of the mutated genes. RESULTS: Whole exome sequencing showed that somatic mutations accumulated in various genes in HCV-infected cirrhotic liver tissues. Among the identified genes, the leptin receptor gene (LEPR) was one of the most frequently mutated in tumor and nontumor cirrhotic liver tissue. Selected exome sequencing analyses detected LEPR mutations in 12 of 22 (54.5%) nontumorous cirrhotic livers. In vitro, 4 of 7 (57.1%) LEPR mutations found in cirrhotic livers reduced phosphorylation of STAT3 to inactivate LEPR-mediated signaling. Moreover, 40% of Lepr-deficient (C57BL/KsJ-db/db) mice developed liver tumors after administration of thioacetamide compared with none of the control mice. CONCLUSIONS: Based on analysis of liver tissue samples from patients, somatic mutations accumulate in LEPR in cirrhotic liver with chronic HCV infection. These mutations could disrupt LEPR signaling and increase susceptibility to hepatocarcinogenesis.
BACKGROUND & AIMS:Hepatocellular carcinoma develops in patients with chronic hepatitis or cirrhosis via a stepwise accumulation of various genetic alterations. To explore the genetic basis of development of hepatocellular carcinoma in hepatitis C virus (HCV)-associated chronic liver disease, we evaluated genetic variants that accumulate in nontumor cirrhotic liver. METHODS: We determined the whole exome sequences of 7 tumors and background cirrhotic liver tissues from 4 patients with HCV infection. We then performed additional sequencing of selected exomes of mutated genes, identified by whole exome sequencing, and of representative tumor-related genes on samples from 22 cirrhotic livers with HCV infection. We performed in vitro and in vivo functional studies for one of the mutated genes. RESULTS: Whole exome sequencing showed that somatic mutations accumulated in various genes in HCV-infected cirrhotic liver tissues. Among the identified genes, the leptin receptor gene (LEPR) was one of the most frequently mutated in tumor and nontumor cirrhotic liver tissue. Selected exome sequencing analyses detected LEPR mutations in 12 of 22 (54.5%) nontumorous cirrhotic livers. In vitro, 4 of 7 (57.1%) LEPR mutations found in cirrhotic livers reduced phosphorylation of STAT3 to inactivate LEPR-mediated signaling. Moreover, 40% of Lepr-deficient (C57BL/KsJ-db/db) mice developed liver tumors after administration of thioacetamide compared with none of the control mice. CONCLUSIONS: Based on analysis of liver tissue samples from patients, somatic mutations accumulate in LEPR in cirrhotic liver with chronic HCV infection. These mutations could disrupt LEPR signaling and increase susceptibility to hepatocarcinogenesis.
Authors: Min Zhu; Tianshi Lu; Yuemeng Jia; Xin Luo; Purva Gopal; Lin Li; Mobolaji Odewole; Veronica Renteria; Amit G Singal; Younghoon Jang; Kai Ge; Sam C Wang; Mahsa Sorouri; Justin R Parekh; Malcolm P MacConmara; Adam C Yopp; Tao Wang; Hao Zhu Journal: Cell Date: 2019-04-04 Impact factor: 41.582