Article

Leptin Receptor Somatic Mutations Are Frequent in HCV-Infected Cirrhotic Liver and Associated With Hepatocellular Carcinoma

Department of Gastroenterology and Hepatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Gastroenterology (Impact Factor: 13.93). 09/2013; 146(1). DOI: 10.1053/j.gastro.2013.09.025
Source: PubMed

ABSTRACT Hepatocellular carcinoma (HCC) develops in patients with chronic hepatitis or cirrhosis via a stepwise accumulation of various genetic alterations. To explore the genetic basis of HCC development in hepatitis C virus (HCV)-associated chronic liver disease, we evaluated genetic variants that accumulate in non-tumor cirrhotic liver.
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 1 of the mutated genes.
Whole-exome sequencing demonstrated 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 non-tumor cirrhotic liver tissue. Selected exome sequencing analyses detected LEPR mutations in 12 of 22 (54.5%) non-tumorous cirrhotic livers. In vitro, 4 of 7 (57.1%) LEPR mutations found in cirrhotic livers reduced phosphorylation of signal transducer and activator of transcription 3 to inactivate LEPR-mediated signaling. Moreover, 40% of Lepr-deficient (C57BL/KsJ-db/db) mice developed liver tumors following administration of thioacetamide, compared with none of the control mice.
Based on analysis of liver tissues 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.

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