GP73, a new marker for diagnosing HBV-ACLF in population with chronic HBV infections

Golgi protein 73: charting new territories in diagnosing significant fibrosis in MASLD: a prospective cross-sectional study

Objectives

To explore the correlation between serum Golgi protein 73 (GP73) levels and the degree of fibrosis in Metabolic dysfunction associated steatotic liver disease (MASLD); to establish a non-invasive diagnostic algorithm based on serum GP73 and liver elasticity.

Methods

This is a prospective cross-sectional study, including 228 patients diagnosed with MASLD from May 2018 to January 2024 at two tertiary hospitals. Clinical data and hepatic pathological features and the correlation between serum GP73 and liver fibrosis were assessed. A new algorithm was conducted after logistic regression. Receiver Operating Characteristic (ROC) curve was used to compare its diagnostic performance with traditional models.

Results

Significant fibrosis was diagnosed in 37.2% (85/228) patients. Serum GP73 levels were markedly higher in patients with significant fibrosis than in those without (128 ng/mL v.s 46 ng/mL, p< 0.001). Serum GP73 levels independently predicted significant liver fibrosis (adjusted odds ratio, aOR 1.028, p< 0.001). A new algorithm based on GP73 was developed with a higher area under ROC (AUC) of 0.840 than that of Fibrosis index-4 (p< 0.001).

Conclusions

Serum GP73 is an independent risk factor for significant liver fibrosis in MASLD, and the GFA (GP73-Fibroscan-Age) model has good diagnostic efficacy for significant liver fibrosis.

Validation of the novel GLAS algorithm as an aid in the detection of liver fibrosis and cirrhosis based on GP73, LG2m, age, and sex

BACKGROUND

Diagnosis of liver disease at earlier stages can improve outcomes and reduce the risk of progression to malignancy. Liver biopsy is the gold standard for diagnosis of liver disease, but is invasive and sample acquisition errors are common. Serum biomarkers for liver function and fibrosis, combined with patient factors, may allow for noninvasive detection of liver disease. In this pilot study, we tested and validated the performance of an algorithm that combines GP73 and LG2m serum biomarkers with age and sex (GLAS) to differentiate between patients with liver disease and healthy individuals in two independent cohorts.

METHODS

To develop the algorithm, prototype immunoassays were used to measure GP73 and LG2m in residual serum samples collected between 2003 and 2016 from patients with staged fibrosis and cirrhosis of viral or non-viral etiology (n = 260) and healthy subjects (n = 133). The performance of five predictive models using combinations of age, sex, GP73, and/or LG2m from the development cohort were tested. Residual samples from a separate cohort with liver disease (fibrosis, cirrhosis, or chronic liver disease; n = 395) and healthy subjects (n = 106) were used to validate the best performing model.

RESULTS

GP73 and LG2m concentrations were higher in patients with liver disease than healthy controls and higher in those with cirrhosis than fibrosis in both the development and validation cohorts. The best performing model included both GP73 and LG2m plus age and sex (GLAS algorithm), which had an AUC of 0.92 (95% CI: 0.90-0.95), a sensitivity of 88.8%, and a specificity of 75.9%. In the validation cohort, the GLAS algorithm had an estimated an AUC of 0.93 (95% CI: 0.90-0.95), a sensitivity of 91.1%, and a specificity of 80.2%. In both cohorts, the GLAS algorithm had high predictive probability for distinguishing between patients with liver disease versus healthy controls.

CONCLUSIONS

GP73 and LG2m serum biomarkers, when combined with age and sex (GLAS algorithm), showed high sensitivity and specificity for detection of liver disease in two independent cohorts. The GLAS algorithm will need to be validated and refined in larger cohorts and tested in longitudinal studies for differentiating between stable versus advancing liver disease over time.

Low Serum Soluble Transferrin Receptor Levels Are Associated with Poor Prognosis in Patients with Hepatitis B Virus-Related Acute-on-Chronic Liver Failure

Iron metabolism disorder is closely related to acute-on-chronic liver failure (ACLF). This study was conducted to analyze the serum levels of soluble transferrin receptor (sTfR) in hepatitis B virus (HBV)-related ACLF and to evaluate the predictive value of sTfR for the short-term prognosis of HBV-ACLF. A total of 359 patients, including 139 with HBV-ACLF, 103 with chronic hepatitis B (CHB), and 117 healthy controls (HCs), participated in this study. We measured serum levels of ferritin, transferrin, and sTfR using nephelometry and performed data analysis using SPSS software. Ferritin levels were significantly higher in HBV-ACLF patients (both P < 0.001), while transferrin and sTfR were significantly lower (all P < 0.001) than in patients with CHB and HCs. Spearman correlation analysis demonstrated that serum sTfR significantly correlated with the alanine aminotransferase (ALT) (r = -0.366, P < 0.001), aspartate aminotransferase (AST) (r = -0.322, P < 0.001), total bilirubin (TBIL) (r = -0.222, P = 0.009), alpha fetoprotein (AFP) (r = 0.329, P < 0.001), prothrombin time-international normalization ratio (PT-INR) (r = -0.428, P < 0.001), and model for end-stage liver disease (MELD) (r = -0.459, P < 0.001). Nonsurviving HBV-ACLF patients who died within 30 days had much lower serum sTfR levels than surviving patients (P < 0.001). Logistic regression analysis showed that decreased serum sTfR levels were independently associated with 30-day mortality in patients with HBV-ACLF (P = 0.003). Receiver operating characteristic (ROC) curve analysis for predicting 30-day mortality showed that the area under the curve (AUC) for serum sTfR was 0.813 (95% CI: 0.738-0.874, P < 0.001). This was similar to that of the MELD score (AUC = 0.812, 95% CI: 0.737-0.873, P < 0.001). Serum sTfR combined with MELD score significantly improved the predictive capacity for 30-day mortality in patients with HBV-ACLF (AUC = 0.871, 95% CI: 0.803-0.922, P < 0.001). Kaplan-Meier analysis revealed that the overall cumulative 30-day mortality rate was significantly higher in patients with serum sTfR levels ≤ 0.55 mg/L compared to those with serum sTfR levels > 0.55 mg/L (P < 0.001).

Short-term prognostic factors for hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND

Acute-on-chronic liver failure (ACLF) is the abrupt exacerbation of declined hepatic function in patients with chronic liver disease.

AIM

To explore the independent predictors of short-term prognosis in patients with hepatitis B virus (HBV)-related ACLF and to establish a predictive short-term prognosis model for HBV-related ACLF.

METHODS

From January 2016 to December 2019, 207 patients with HBV-related ACLF attending the 910th Hospital of Chinese People's Liberation Army were continuously included in this retrospective study. Patients were stratified based on their survival status 3 mo after diagnosis. Information was collected regarding gender and age; coagulation function in terms of prothrombin time and international normalized ratio (INR); hematological profile in terms of neutrophil-to-lymphocyte ratio (NLR) and platelet count (PLT); blood biochemistry in terms of alanine aminotransferase, aspartate aminotransferase, total bilirubin (Tbil), albumin, cholinesterase, blood urea nitrogen (BUN), creatinine, blood glucose, and sodium (Na); tumor markers including alpha-fetoprotein (AFP) and Golgi protein 73 (GP73); virological indicators including HBV-DNA, HBsAg, HBeAg, Anti-HBe, and Anti-HBc; and complications including hepatic encephalopathy, hepatorenal syndrome, spontaneous peritonitis, gastrointestinal bleeding, and pulmonary infection.

RESULTS

There were 157 and 50 patients in the survival and death categories, respectively. Univariate analysis revealed significant differences in age, PLT, Tbil, BUN, NLR, HBsAg, AFP, GP73, INR, stage of liver failure, classification of liver failure, and incidence of complications (pulmonary infection, hepatic encephalopathy, spontaneous bacterial peritonitis, and upper gastrointestinal bleeding) between the two groups (P < 0.05). GP73 [hazard ratio (HR): 1.009, 95% confidence interval (CI): 1.005-1.013, P = 0.000], middle stage of liver failure (HR: 5.056, 95%CI: 1.792-14.269, P = 0.002), late stage of liver failure (HR: 22.335, 95%CI: 8.544-58.388, P = 0.000), pulmonary infection (HR: 2.056, 95%CI: 1.145-3.690, P = 0.016), hepatorenal syndrome (HR: 6.847, 95%CI: 1.930-24.291, P = 0.003), and HBsAg (HR: 0.690, 95%CI: 0.524-0.908, P = 0.008) were independent risk factors for short-term prognosis in patients with HBV-related ACLF. Following binary logistics regression analysis, we arrived at the following formula for predicting short-term prognosis: Logit(P) = Ln(P/1-P) = 0.013 × (GP73 ng/mL) + 1.907 × (middle stage of liver failure) + 4.146 × (late stage of liver failure) + 0.734 × (pulmonary infection) + 22.320 × (hepatorenal syndrome) - 0.529 × (HBsAg) - 5.224. The predictive efficacy of the GP73-ACLF score was significantly better than that of the Model for End-Stage Liver Disease (MELD) and MELD-Na score models (P < 0.05).

CONCLUSION

The stage of liver failure, presence of GP73, pulmonary infection, hepatorenal syndrome, and HBsAg are independent predictors of short-term prognosis in patients with HBV-related ACLF, and the GP73-ACLF model has good predictive value among these patients.

Relationship between the Level of Serum Golgi Protein 73 and the Risk of Short-term Death in Patients with ALD-ACLF

BACKGROUND AND AIMS

As a hepatocellular carcinoma biomarker, serum Golgi protein 73 (GP73) is reportedly related to inflammation. Acute-on-chronic liver failure (ACLF) is characterized by severe systemic inflammation. In this study, we aimed to explore the association between the GP73 level and short-term mortality in patients with alcohol-associated liver disease-related ACLF (ALD-ACLF).

METHODS

This retrospective cohort study involved 126 Chinese adults with ALD-ACLF. Baseline serum GP73 level was measured using enzyme-linked immunosorbent assay. Patients were followed-up for 90 d and outcomes were assessed. Data were analyzed using multivariate Cox regression and piecewise linear regression analyses. The predictive value of GP73 and classic models for the short-term prognosis of participants were evaluated and compared using receiver operating characteristic curves.

RESULTS

The serum GP73 level was independently associated with an increased mortality risk in patients with ALD-ACLF. Compared with the lowest tertile, the highest serum GP73 level predisposed patients with ALD-ACLF to a higher mortality risk in the fully adjusted model [at 28 days: hazard ratio (HR): 4.29 (0.99-18.54), p=0.0511; at 90 days: HR: 3.52 (1.15-10.79), p=0.0276]. Further analysis revealed a positive linear association. GP73 significantly improved the accuracy of the Child-Turcotte-Pugh score, model for end-stage liver disease score, and model for end-stage liver disease-sodium score in predicting short-time prognosis of patients with ALD-ACLF.

CONCLUSIONS

The serum GP73 level is a significant predictor of the subsequent risk of death in patients with ALD-ACLF. GP73 improved the predictive value of classic prognostic scores.

Golgi Phosphoprotein 73: The Driver of Epithelial-Mesenchymal Transition in Cancer

Golgi phosphoprotein 73 (GP73, also termed as GOLM1 or GOLPH2) is a glycosylated protein residing on cis-Golgi cisternae and highly expressed in various types of cancer tissues. Since GP73 is a secretory protein and detectable in serum derived from cancer patients, it has been regarded as a novel serum biomarker for the diagnosis of different cancers, especially hepatocellular carcinoma (HCC). However, the functional roles of GP73 in cancer development are still poorly understood. In recent years, it has been discovered that GP73 acts as a multifunctional protein-facilitating cancer progression, and strikingly, it has been identified as a leading factor promoting epithelial-mesenchymal transition (EMT) of cancer cells and causing cancer metastasis. In this review, we have overviewed the latest findings of the functional roles of GP73 in elevating cancer progression, especially in facilitating EMT and cancer metastasis through modulating expression, transactivation, and trafficking of EMT-related proteins. In addition, unsolved research fields of GP73 have been lightened, which might be helpful to elucidate the regulatory mechanisms of GP73 on EMT and provide potential approaches in therapeutics against cancer metastasis.

Serum Cartilage Oligomeric Matrix Protein and Golgi Protein-73: New Diagnostic and Predictive Tools for Liver Fibrosis and Hepatocellular Cancer?

Simple Summary

Hepatocellular carcinoma (HCC) ranks as the sixth most common malignancy and represents the fourth leading cause of cancer-related deaths. However, most HCC cases are insidious in the early stages leading to a delay in diagnosis with limited treatment options. In patients with chronic liver diseases, advanced liver fibrosis and cirrhosis are the leading risk factors for the development of HCC. Cartilage oligomeric matrix protein (COMP) and Golgi protein-73 (GP73) are two biomarkers that have been associated with the progression of chronic liver disease, including inflammation, fibrosis, and HCC. The aim of our study was to assess the performance of the combination of these biomarkers. We confirmed, in a large cohort of 288 patients with chronic liver diseases, that the combination of GP73 and COMP had a high discriminative ability to detect severe fibrosis/cirrhosis and is efficient in predicting the development of HCC.

Abstract

The cartilage oligomeric matrix protein (COMP) and Golgi-protein-73 (GP73) have been proposed as markers of liver fibrosis and hepatocellular carcinoma (HCC). Our aim was to assess the performance of the combination of these markers in diagnosing cirrhosis and predicting HCC development. Sera from 288 consecutive patients with chronic liver diseases were investigated by using COMP and GP73-ELISAs. Dual positivity for COMP (>15 U/L) and GP73 (>20 units) was observed in 24 (8.3%) patients, while 30 (10.4%) were GP73(+)/COMP(−), 37/288 (12.8%) GP73(−)/COMP(+), and 197 (68.5%) GP73(−)/COMP(−). Positivity for both markers was associated with cirrhosis [23/24 (95.8%) for GP73(+)/COMP(+) vs. 22/30 (73.3%) for GP73(+)/COMP(−) vs. 25/37 (67.6%) for GP73(−)/COMP(+) vs. 46/197 (23.4%) for GP73(−)/COMP(−); P < 0.001]. The combination of GP73, COMP, the aspartate aminotransferase/platelets ratio index, and the Fibrosis-4 score had even higher diagnostic accuracy to detect the presence of cirrhosis [AUC (95% CI): 0.916 (0.878–0.946)] or significant liver fibrosis (METAVIR ≥ F2) [AUC (95% CI): 0.832 (0.768–0.883)] than each marker alone. Kaplan-Meier analysis showed that positivity for both GP73 and COMP was associated with higher rates of HCC development (P < 0.001) and liver-related deaths (P < 0.001) during follow-up. In conclusion, the combination of GP73 and COMP seems efficient to detect cirrhosis and predict worse outcomes and the development of HCC in patients with chronic liver diseases.

Exploring the Diagnostic Potential of Serum Golgi Protein 73 for Hepatic Necroinflammation and Fibrosis in Chronic HCV Infection with Different Stages of Liver Injuries

BACKGROUND AND AIM

Serum Golgi protein 73 (GP73) is a promising alternative biomarker of chronic liver diseases, but most data are from patients with HBV infection rather than HCV.

MATERIALS AND METHODS

Two independent cohorts of chronic hepatitis C (CHC) patients from the 5th Medical Centre of the Chinese PLA General Hospital (n = 174) and Beijing Youan Hospital (n = 120) with different histories of HCV infection were enrolled. The correlations between serum GP73 and other biochemical indices, as well as its correlations with different stages of liver disease progression, were investigated. The receiver operating characteristic (ROC) curve was employed to evaluate the diagnostic potential of serum GP73 for liver necroinflammation and fibrosis, and comparisons of the diagnostic efficiency with traditional indices of hepatic liver injuries were further investigated.

RESULTS

Levels of serum GP73 were found significantly elevated in patients with moderate to severe inflammatory grade (G ≥ 2) and/or with advanced fibrotic stages (F ≥ 3) in both cohorts (P < 0.05, respectively), as compared to those with a normal or mild liver lesion. Further ROC analysis demonstrated that serum GP73 was comparable to serum ALT and AST in diagnosing the liver necroinflammation grade at G ≥ 2, but its diagnostic values for advanced fibrosis (F ≥ 3) and cirrhosis (F = 4) were limited when compared to APRI and FIB-4, and FIB-4 exhibited the best performance. Notably, an obvious elevation of serum GP73 was observed after patients received PEG-IFN and ribavirin treatment.

CONCLUSIONS

Serum GP73 is an important biomarker in evaluating and monitoring the disease progression including liver necroinflammation and fibrosis in patients with chronic HCV infection, but the value is limited for diagnosing advanced fibrosis and cirrhosis in comparison with APRI and FIB-4.

Effect of sample type and storage conditions on Golgi membrane protein 73 stability

GP73 is a transmembrane glycoprotein that increases in viral and non-viral liver diseases, especially in hepatocellular carcinoma. This study aims to evaluate the effect of sample type and storage conditions on GP73 concentration. Twenty subjects were enrolled in this study. Serum and citrated plasma samples were collected. Both were subjected to different time intervals and storage temperature. Baseline GP73 concentrations ranged from 1.7 to 16.9 ng/mL in serum samples, and from 1.1 to 15.3 ng/mL in citrated plasma (Mann-Whitney U test, p = .1). The acceptable change limit for GP73 was 6.1%. As the highest value of the median percentage deviation was -5.3% in both sample types at different storage condition so, deviations were within the accepted limits. But there were considerable variations in the GP-73 concentrations after 2 cycles of freezing and thawing at -20 °C. This study shows that both serum and citrated plasma can be used for the measurement of GP73 concentration. GP73 seems to be stable under common storage conditions, but it may be unstable with frequent cycles of freezing and thawing.

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.

Serum Golgi protein 73 is a marker comparable to APRI for diagnosing significant fibrosis in children with liver disease

Serum Golgi protein 73 (GP73) is a promising marker for significant fibrosis in adults. However, current diagnostic value of serum GP73 for liver fibrosis in children is unknown. To investigate the relationship between levels of serum GP73 and liver fibrosis in children, we measured serum GP73 in 86 healthy controls and 183 patients with liver diseases using commercially available double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) kit. The value of serum GP73 in fibrosis stage assessment was compared with aspartate transaminase to platelet ratio index (APRI). We found that serum GP73 was decreasing with age in healthy controls, while it was increasing with the extent of inflammation and fibrosis in patients with liver diseases. Though area under the receiver operating curve (AUROC) of serum GP73 for diagnosing significant fibrosis was nearly equal to APRI (0.62 vs 0.64) in patients aged 3 years or older, AUROC for serum GP73 was superior to APRI (0.76 vs 0.67) in patients aged below 3 years, indicating that serum GP73 is comparable to APRI for diagnosing significant fibrosis in children.

Development of an alpha-fetoprotein and Golgi protein 73 multiplex detection assay using xMAP technology

AIM OF THE STUDY

Development of a new method to simultaneously detect Alpha-fetoprotein (AFP) and Golgi protein 73 (GP73) from peripheral blood.

MATERIAL AND METHODS

Anti human AFP and GP73 monoclonal antibodies was used to develop a sandwich immunity reaction using xMAP technology for the simultaneous detection of plasma AFP and GP73. The assay evaluated the sensitivity, cross reactivity, range of detection, precision, recovery and linearity dilution effect. The assay utilized plasma samples and compared its performance with commercially available Enzyme Linked Immunosorbent Assay (ELISA) kits.

RESULTS

The assay was successful in detecting AFP and GP73 simultaneously. Validation experiments demonstrated the limit of detection was AFP 0.006 μg/l and GP73 0.482 μg/l. The functional sensitivity was AFP 0.010 μg/l and GP73 0.640 μg/l. The range of detection was AFP 0.01-50 μg/l and GP73 0.64-100 μg/l. No cross reactivity was observed. The intra- and inter-assay variation for AFP was 0.19-3.46% and 3.1-5.8% and for GP73 was 1.5-3.2% and 1.1-7.6% respectively. The recovery for AFP was 96-106% and GP73 was 89-110%. 80 clinical plasma samples from healthy controls, and patients with liver cirrhosis and Hepatocellular Carcinoma (HCC) were evaluated. For healthy controls (n = 25), the AFP was 2.40 (1.55, 3.30) μg/l and GP73 was 42.60 (39.10, 57.40) μg/l. For patients with liver cirrhosis (n = 19), the AFP was 2.60 (1.70, 4.20) μg/l and GP73 was 136.10 (92.10, 261.70) μg/l, and for HCC patients (n = 36), the AFP was 13.65 (3.35, 158.88) μg/l and GP73 was 186.25 (96.73, 262.03) μg/l. The new assay demonstrated a good correlation with commercially available ELISA kits (correlation coefficients (r) were 0.997 (AFP, p < 0.001) and 0.959 (GP73, p < 0.001).

CONCLUSIONS

The method demonstrated a sensitive, effective and accurate method for the simultaneous detection of AFP and GP73, and could be used clinically for routine detection and monitoring of patients with chronic hepatitis B.

Acute-on-chronic liver failure in chronic hepatitis B: an update

Acute-on-chronic liver failure is a common pattern of end-stage liver disease in clinical practice and occurs frequently in patients with chronic hepatitis B or HBV-related cirrhosis. New progress in recent years leads to a better understanding of this disease. Areas covered: This review updates the current comprehensive knowledge about HBV-ACLF from epidemiological studies, experimental studies, and clinical studies and provide new insights into the definition, diagnostic criteria, epidemiology, nature history, pathogenesis, treatment and prognostication of HBV-ACLF. Expert commentary: Patients with chronic hepatitis B or HBV-related cirrhosis are at risk of developing acute-on-chronic liver failure, with multi-organ failure and high short-term mortality. The precipitating events can be intra-hepatic or extra-hepatic and the underlying chronic liver injury can be cirrhotic or non-cirrhotic. Host and viral factors contribute to the susceptibility of developing HBV-ACLF. Systemic inflammation is the driver of HBV-ACLF, which can be attributed to non-sterile and sterile factors. Liver transplantation is the definitive treatment for HBV-ACLF. Cell therapy is a promising alternative to LT, but requires validation and still has concern of long-term safety. Other medical therapies, such as nucleoside analogue, artificial liver supporting and glucocorticoid may improve survival in a specific subgroup. New scoring systems improve the accuracy of prognostication in HBV-ACLF, which is critical for early identification of candidates for LT.

Discovery of a Potential Plasma Protein Biomarker Panel for Acute-on-Chronic Liver Failure Induced by Hepatitis B Virus

Hepatitis B virus (HBV)-associated acute-on-chronic liver failure (HBV-ACLF), characterized by an acute deterioration of liver function in the patients with chronic hepatitis B (CHB), is lack of predicting biomarkers for prognosis. Plasma is an ideal sample for biomarker discovery due to inexpensive and minimally invasive sampling and good reproducibility. In this study, immuno-depletion of high-abundance plasma proteins followed by iTRAQ-based quantitative proteomic approach was employed to analyze plasma samples from 20 healthy control people, 20 CHB patients and 20 HBV-ACLF patients, respectively. As a result, a total of 427 proteins were identified from these samples, and 42 proteins were differentially expressed in HBV-ACLF patients as compared to both CHB patients and healthy controls. According to bioinformatics analysis results, 6 proteins related to immune response (MMR), inflammatory response (OPN, HPX), blood coagulation (ATIII) and lipid metabolism (APO-CII, GP73) were selected as biomarker candidates. Further ELISA analysis confirmed the significant up-regulation of GP73, MMR, OPN and down-regulation of ATIII, HPX, APO-CII in HBV-ACLF plasma samples (p < 0.01). Moreover, receiver operating characteristic (ROC) curve analysis revealed high diagnostic value of these candidates in assessing HBV-ACLF. In conclusion, present quantitative proteomic study identified 6 novel HBV-ACLF biomarker candidates and might provide fundamental information for development of HBV-ACLF biomarker.

Knockdown of Golgi phosphoprotein 2 inhibits hepatocellular carcinoma cell proliferation and motility

Golgi phosphoprotein 2 (GP73) is highly expressed in hepatocellular carcinoma (HCC) cells, where it serves as a biomarker and indicator of disease progression. We used MTS assays, anchorage-independent cell colony formation assays and a xenograft tumor model to show that GP73-specific siRNAs inhibit HCC proliferation in HepG2, SMMC-7721, and Huh7 cell lines and in vivo. Following GP73 silencing, levels of p-Rb, a factor related to metastasis, were reduced, but cell cycle progression was unaffected. Our results suggest that GP73 silencing may not directly suppress proliferation, but may instead inhibit cell motility. Results from proliferation assays suggest GP73 reduces expression of epithelial mesenchymal transition (EMT)-related factors and promotes cell motility, while transwell migration and invasion assays indicated a possible role in metastasis. Immunofluorescence co-localization microscopy and immunoblotting showed that GP73 decreases expression of N-cadherin and E-cadherin, two key factors in EMT, which may in turn decrease intracellular adhesive forces and promote cell motility. This study confirmed that GP73 expression leads to increased expression of EMT-related proteins and that GP73 silencing reduces HCC cell migration in vitro. These findings suggest that GP73 silencing through siRNA delivery may provide a novel low-toxicity therapy for the inhibition of tumor proliferation and metastasis.

Abnormal Expression of Golgi Protein 73 in Clinical Values and Their Role in HBV-Related Hepatocellular Carcinoma Diagnosis and Prognosis

BACKGROUND

The up-regulation of hepatic Golgi protein 73 (GP73) is associated with the progression of hepatocellular carcinoma (HCC). However, the exact mechanism and clinical values of its diagnosis and prognosis still need to be clarified.

OBJECTIVES

To investigate the clinical values of abnormal liver or circulating GP73 expression and their effect on HCC diagnosis and prognosis.

MATERIALS AND METHODS

The expression of GP73 was investigated in 88 cancerous and self-control non-cancerous tissues using tissue microarrays with immunohisto- chemistry and was confirmed by Western blotting. Circulating GP73 levels were detected in the sera of 281 patients with liver diseases using enzyme-linked immunosorbent assay.

RESULTS

The levels of circulating GP73 expression in the HCC group were higher than those in any group of benign liver diseases or controls. No significant difference was found between GP73 expression and patients' sex or age, tumor size, or AFP level except for those with hepatitis B virus (HBV) infection or distal metastasis (P < 0.05). The area under the receiver operating characteristic curve, sensitivity, and specificity for HCC diagnosis were 0.881, 78.34%, and 77.59% for GP73 levels over 70 μg/L or 0.754, 71.97%, and 84.48% for alpha-fetoprotein levels over 50 μg/L, respectively. The total incidence of GP73 plus alpha-fetoprotein was up to 87.26% for HCC. A positive GP73 result with brown particles was mainly located in the cytosol, with a few in the nucleus and none in the cell membrane, with abnormal expression in HCC tissues (480.7 ± 148.7) that was significantly higher (t = 10.730, P < 0.001) than those in their non-cancerous tissues (208.0 ± 66.1). The high GP73 expression in HCC was related to lymph node metastasis (χ(2) = 6.940, P = 0.008), gross classification (χ(2) = 6.311, P = 0.012), HBV (χ(2) = 4.803, P = 0.028), tumor node metastasis staging (χ(2) = 4.887, P = 0.027), and five-year survival (χ(2) = 5.206, P = 0.023).

CONCLUSIONS

Abnormality of hepatic or circulating GP73 expression should be regarded as an emerging biomarker for HCC diagnosis and prognosis.

Diagnostic value of combined detection of angiopoietin-2 and Golgi protein 73 in primary liver cancer

AIM: To detect the expression of circulating angiopoietin-2 (Ang-2) and Golgi protein 73 (GP73) in patients with primary liver cancer and to analyze their value in the diagnosis and differential diagnosis of primary liver cancer (PLC).

METHODS: The levels of circulating Ang-2 and GP73 expression were detected by ELISA in patients with PLC, acute hepatitis, chronic hepatitis, or liver cirrhosis. The expression of Ang-2 and GP73 in cancerous and surrounding noncancerous tissues was analyzed by immunohistochemistry and confirmed by Western blot.

RESULTS: Positive expression of hepatic GP73 and Ang-2 was characterized by the presence of brown granules in the cytoplasm or cytomembrane. Hepatic GP73 and Ang-2 expression was significantly higher in cancerous tissue than in surrounding noncancerous tissue (P < 0.01). The levels of circulating Ang-2 and GP73 in PLC patients (40.8 ng/mL ± 3.5 ng/mL and 87.3 ng/mL ± 78.4 ng/mL, respectively) were significantly higher (P < 0.01) than those in normal subjects and patients with acute hepatitis, chronic hepatitis, or liver cirrhosis. There was a positive correlation between Ang-2 and GP73 (r = 0.987, P = 0.013). The area under the receiver operating curve (ROC) for the diagnosis of PLC was 0.915 for Ang-2 and 0.899 for GP73.

CONCLUSION: The overexpression of Ang-2 and GP73 is associated with HCC development and may be useful biomarkers for PLC diagnosis or differential diagnosis.

Evaluation of a magnetic particles-based chemiluminescence enzyme immunoassay for Golgi protein 73 in human serum

BACKGROUND

Golgi protein 73 (GP73) is regarded as a potential serum biomarker for early diagnosis of hepatocellular carcinoma (HCC). We developed a rapid magnetic particles-based chemiluminescence enzyme immunoassay (MPs-CLEIA) for the determination of serum GP73.

METHODS

Fluorescein isothiocyanate (FITC) and alkaline phosphatase (ALP) were used to label 2 different monoclonal antibodies to GP73. Serum GP73 was captured with labeled antibodies and formed a sandwiched immunoreaction. The magnetic particles (MPs) coated with anti-FITC antibody were used as a means of separation of the GP73 protein from other serum proteins. After adding the enzyme substrate solution, the relative light unit (RLU) was measured. A MPs-CLEIA for serum GP73 was established and evaluated.

RESULTS

The RLU was directly proportional to the concentration of GP73. The method linearity was 5-600 μg/l. Limit of the blank was 2.19 μg/l. The intra- and inter-assay imprecision was <3% and <5%, respectively. The average recoveries were between 95% and 105%. The proposed method showed a good correlation with a commercial ELISA assay (r=0.983, p<0.001). We also evaluated the efficiency of serum GP73 measurement for the diagnosis of HCC using this assay. The area under the receiver operating characteristic curve was 0.822 (95% CI, 0.73-0.89), and the sensitivity and specificity, with cut-off value of 115.6 μg/l, were 75.4% and 92.1%, respectively.

CONCLUSIONS

The proposed method demonstrates an acceptable performance for quantifying serum GP73. This assay could be appropriate for routine use in clinical laboratories.