Hepatitis B virus upregulates GP73 expression by activating the HIF-2α signaling pathway

Use of GP73 in the diagnosis of non-alcoholic steatohepatitis and the staging of hepatic fibrosis

Objective

To evaluate the utility of Golgi protein 73 (GP73) in the diagnosis of non-alcoholic steatohepatitis (NASH) and hepatic fibrosis (HF) staging.

Methods

Ninety-one patients with non-alcoholic fatty liver disease (NAFLD) were allocated to NAFL (n = 46) and NASH (n = 45) groups according to their NAFLD activity score (NAS), and there were 30 healthy controls. Serum GP73 was measured by ELISA, GP73 protein expression was evaluated using immunohistochemistry, and FibroScan was used to determine liver hardness.

Results

The serum GP73 concentrations of the NAFL and NASH groups were significantly higher than those of controls. GP73 expression in the liver of the patients gradually progressed from absent or low to moderate or high. Serum GP73 positively correlated with liver expression, and the serum and liver GP73 of the patients positively correlated with FibroScan value and HF stage. There was a strong positive correlation of the combination of alanine aminotransferase, gamma glutamyl transferase and GP73 with NASH. The combination of serum GP73 and FibroScan value was found to predict NASH (NAS > 4) and advanced HF (stage ≥2) in patients with NAFLD using receiver operating characteristic analysis.

Conclusion

Serum GP73 may be useful in the diagnosis of NASH and the staging of HF.

Profibrotic Signaling and HCC Risk during Chronic Viral Hepatitis: Biomarker Development

Despite breakthroughs in antiviral therapies, chronic viral hepatitis B and C are still the major causes of liver fibrosis and hepatocellular carcinoma (HCC). Importantly, even in patients with controlled infection or viral cure, the cancer risk cannot be fully eliminated, highlighting a persisting oncogenic pressure imposed by epigenetic imprinting and advanced liver disease. Reliable and minimally invasive biomarkers for early fibrosis and for residual HCC risk in HCV-cured patients are urgently needed. Chronic infection with HBV and/or HCV dysregulates oncogenic and profibrogenic signaling within the host, also displayed in the secretion of soluble factors to the blood. The study of virus-dysregulated signaling pathways may, therefore, contribute to the identification of reliable minimally invasive biomarkers for the detection of patients at early-stage liver disease potentially complementing existing noninvasive methods in clinics. With a focus on virus-induced signaling events, this review provides an overview of candidate blood biomarkers for liver disease and HCC risk associated with chronic viral hepatitis and epigenetic viral footprints.

Golgi protein 73, hepatocellular carcinoma and other types of cancers

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a low survival rate. The identification of mechanisms underlying the development of HCC helps uncover cellular and molecular targets for the diagnosis, prevention, and treatment of HCC. Golgi protein 73 (GP73) level is upregulated in HCC patients and potentially can be a therapeutic target. Despite many studies devoted to GP73 as a marker for HCC early diagnosis, there is little discussion about the function of GP73 in HCC tumorigenesis. Given the poor response to currently available HCC therapies, a better understanding of the role of GP73 in HCC may provide a new therapeutic target for HCC. The current paper summarizes the role of GP73 as a diagnostic marker as well as its roles in liver carcinogenesis. Its roles in other types of cancer are also discussed.

Golgi protein 73 and its diagnostic value in liver diseases

Golgi protein 73 (GP73, also referred to as Golph 2) with 400 amino acids is a 73 kDa transmembrane glycoprotein typically found in the cis-Golg complex. It is primarily expressed in epithelial cells, which has been found upregulated in hepatocytes in patients suffering from both viral and non-viral liver diseases. GP73 has drawn increasing attention for its potential application in the diagnosis of liver diseases such as hepatitis, liver cirrhosis and liver cancer. Herein, we reviewed the discovery history of GP73 and summarized studies by many groups around the world, aiming at understanding its structure, expression, function, detection methods and the relationship between GP73 and liver diseases in various settings.