Endosomal trafficking and proprotein convertase cleavage of cis Golgi protein GP73 produces marker for hepatocellular carcinoma

Integrating Single-Cell and Spatial Transcriptomics to Uncover and Elucidate GP73-Mediated Pro-Angiogenic Regulatory Networks in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) was characterized as being hypervascular. In the present study, we generated a single-cell spatial transcriptomic landscape of the vasculogenic etiology of HCC and illustrated overexpressed Golgi phosphoprotein 73 (GP73) HCC cells exerting cellular communication with vascular endothelial cells with high pro-angiogenesis potential via multiple receptor-ligand interactions in the process of tumor vascular development. Specifically, we uncovered an interactive GP73-mediated regulatory network coordinated with c-Myc, lactate, Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway, and endoplasmic reticulum stress (ERS) signals in HCC cells and elucidated its pro-angiogenic roles in vitro and in vivo. Mechanistically, we found that GP73, the pivotal hub gene, was activated by histone lactylation and c-Myc, which stimulated the phosphorylation of downstream STAT3 by directly binding STAT3 and simultaneously enhancing glucose-regulated protein 78 (GRP78)-induced ERS. STAT3 potentiates GP73-mediated pro-angiogenic functions. Clinically, serum GP73 levels were positively correlated with HCC response to anti-angiogenic regimens and were essential for a prognostic nomogram showing good predictive performance for determining 6-month and 1-year survival in patients with HCC treated with anti-angiogenic therapy. Taken together, the aforementioned data characterized the pro-angiogenic roles and mechanisms of a GP73-mediated network and proved that GP73 is a crucial tumor angiogenesis niche gene with favorable anti-angiogenic potential in the treatment of HCC.

Progress in pH-Sensitive sensors: essential tools for organelle pH detection, spotlighting mitochondrion and diverse applications

pH-sensitive fluorescent proteins have revolutionized the field of cellular imaging and physiology, offering insight into the dynamic pH changes that underlie fundamental cellular processes. This comprehensive review explores the diverse applications and recent advances in the use of pH-sensitive fluorescent proteins. These remarkable tools enable researchers to visualize and monitor pH variations within subcellular compartments, especially mitochondria, shedding light on organelle-specific pH regulation. They play pivotal roles in visualizing exocytosis and endocytosis events in synaptic transmission, monitoring cell death and apoptosis, and understanding drug effects and disease progression. Recent advancements have led to improved photostability, pH specificity, and subcellular targeting, enhancing their utility. Techniques for multiplexed imaging, three-dimensional visualization, and super-resolution microscopy are expanding the horizon of pH-sensitive protein applications. The future holds promise for their integration into optogenetics and drug discovery. With their ever-evolving capabilities, pH-sensitive fluorescent proteins remain indispensable tools for unravelling cellular dynamics and driving breakthroughs in biological research. This review serves as a comprehensive resource for researchers seeking to harness the potential of pH-sensitive fluorescent proteins.

Novel serum biomarker of Golgi protein 73 for the diagnosis of clinically significant portal hypertension in patients with compensated cirrhosis

Hepatic venous pressure gradient (HVPG) is the gold standard for evaluating clinically significant portal hypertension (CSPH). However, reliable noninvasive methods are limited. Our study aims to investigate the diagnostic value of serum Golgi protein 73 (GP73) for CSPH in patients with compensated cirrhosis. The study enrolled 262 consecutive patients with compensated cirrhosis from three centers in China from February 2021 to September 2023, who underwent both serum GP73 tests and HVPG measurements. CSPH was defined as HVPG ≥ 10 mmHg. Diagnostic accuracy was evaluated using the areas under the receiver operating characteristic curve (AUC). The prevalence of CSPH was 56.9% (n = 149). There were significant differences between the CSPH and non-CSPH groups in the median serum GP73 level (126.8 vs. 73.1 ng/mL, p < 0.001). GP73 level showed a significant positive linear correlation with HVPG (r = 0.459, p < 0.001). The AUC for the diagnosis of CSPH using serum GP73 alone was 0.75 (95% confidence interval [CI] 0.68-0.81). Multivariate logistic regression analysis determined that the levels of GP73, platelets and international normalized ratio were independently associated with CSPH. The combination of these three markers was termed "IP73" score with an AUC value of 0.85 (95% CI 0.80-0.89) for CSPH. Using 0 as a cut-off value, the specificity and sensitivity of IP73 score were 77.9% and 81.9%, respectively. The IP73 score offers a novel, simple and noninvasive method of assessing CSPH in patients with compensated cirrhosis. A cut-off value of the IP73 score at 0 can distinguish patients with or without CSPH.

Unveiling the impact of GOLM1/GP73 on cytokine production in cancer and infectious disease

The Golgi membrane protein GOLM1/GP73/GOLPH2 has been found to impact cytokine production in both infectious disease and cancer. In viral infections, GOLM1 levels are increased, and this lowers the production of type I interferons and other inflammatory cytokines. However, elevated GOLM1 expression levels due to mutations are linked to a higher production of interleukin (IL)-6 during Candida infections, potentially explaining an increased susceptibility to candidemia in individuals carrying these mutations. In cancer, the protease Furin produces a soluble form of GOLM1 that has oncogenic properties by promoting the production of the chemokine CCL2 and suppressing the production of inflammatory cytokines such as IL-12 and interferon gamma. This review will focus on the role of GOLM1 in cytokine production, highlighting how it can both promote and inhibit cytokine production. It is crucial to understand this in order to effectively target GOLM1 for therapeutic purposes in diseases associated with abnormal cytokine production, including cancer and infectious disease.

The crescent-like Golgi ribbon is shaped by the Ajuba/PRMT5/Aurora-A complex-modified HURP

BACKGROUND

Golgi apparatus (GA) is assembled as a crescent-like ribbon in mammalian cells under immunofluorescence microscope without knowing the shaping mechanisms. It is estimated that roughly 1/5 of the genes encoding kinases or phosphatases in human genome participate in the assembly of Golgi ribbon, reflecting protein modifications play major roles in building Golgi ribbon.

METHODS

To explore how Golgi ribbon is shaped as a crescent-like structure under the guidance of protein modifications, we identified a protein complex containing the scaffold proteins Ajuba, two known GA regulators including the protein kinase Aurora-A and the protein arginine methyltransferase PRMT5, and the common substrate of Aurora-A and PRMT5, HURP. Mutual modifications and activation of PRMT5 and Aurora-A in the complex leads to methylation and in turn phosphorylation of HURP, thereby producing HURP p725. The HURP p725 localizes to GA vicinity and its distribution pattern looks like GA morphology. Correlation study of the HURP p725 statuses and GA structure, site-directed mutagenesis and knockdown-rescue experiments were employed to identify the modified HURP as a key regulator assembling GA as a crescent ribbon.

RESULTS

The cells containing no or extended distribution of HURP p725 have dispersed GA membranes or longer GA. Knockdown of HURP fragmentized GA and HURP wild type could, while its phosphorylation deficiency mutant 725A could not, restore crescent Golgi ribbon in HURP depleted cells, collectively indicating a crescent GA-constructing activity of HURP p725. HURP p725 is transported, by GA membrane-associated ARF1, Dynein and its cargo adaptor Golgin-160, to cell center where HURP p725 forms crescent fibers, binds and stabilizes Golgi assembly factors (GAFs) including TRIP11, GRASP65 and GM130, thereby dictating the formation of crescent Golgi ribbon at nuclear periphery.

CONCLUSIONS

The Ajuba/PRMT5/Aurora-A complex integrates the signals of protein methylation and phosphorylation to HURP, and the HURP p725 organizes GA by stabilizing and recruiting GAFs to its crescent-like structure, therefore shaping GA as a crescent ribbon. Therefore, the HURP p725 fiber serves a template to construct GA according to its shape. Video Abstract.

GP73 blockade alleviates abnormal glucose homeostasis in diabetic mice

Golgi protein 73 (GP73), also called Golgi membrane protein 1 (GOLM1), is a resident Golgi type II transmembrane protein and is considered as a serum marker for the detection of a variety of cancers. A recent work revealed the role of the secreted GP73 in stimulating liver glucose production and systemic glucose homeostasis. Since exaggerated hepatic glucose production plays a key role in the pathogenesis of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), GP73 may thus represent a potential therapeutic target for treating diabetic patients with pathologically elevated levels. Here, in this study, we found that the circulating GP73 levels were significantly elevated in T2DM and positively correlated with hemoglobin A1c. Notably, the aberrantly upregulated GP73 levels were indispensable for the enhanced protein kinase A signaling pathway associated with diabetes. In diet-induced obese mouse model, GP73 siRNA primarily targeting liver tissue was potently effective in alleviating abnormal glucose metabolism. Ablation of GP73 from whole animals also exerted a profound glucose-lowering effect. Importantly, neutralizing circulating GP73 improved glucose metabolism in streptozotocin (STZ) and high-fat diet/STZ-induced diabetic mice. We thus concluded that GP73 was a feasible therapeutic target for the treatment of diabetes.

Endogenous tagging reveals a mid-Golgi localization of the glycosyltransferase-cleaving intramembrane protease SPPL3

Numerous Golgi-resident enzymes implicated in glycosylation are regulated by the conserved intramembrane protease SPPL3. SPPL3-catalyzed endoproteolysis separates Golgi enzymes from their membrane anchors, enabling subsequent release from the Golgi and secretion. Experimentally altered SPPL3 expression changes glycosylation patterns, yet the regulation of SPPL3-mediated Golgi enzyme cleavage is not understood and conflicting results regarding the subcellular localization of SPPL3 have been reported. Here, we used precise genome editing to generate isogenic cell lines expressing N- or C-terminally tagged SPPL3 from its endogenous locus. Using these cells, we conducted co-localization analyses of tagged endogenous SPPL3 and Golgi markers under steady-state conditions and upon treatment with drugs disrupting Golgi organization. Our data demonstrate that endogenous SPPL3 is Golgi-resident and found predominantly in the mid-Golgi. We find that endogenous SPPL3 co-localizes with its substrates but similarly with non-substrate type II proteins, demonstrating that in addition to co-localization in the Golgi other substrate-intrinsic properties govern SPPL3-mediated intramembrane proteolysis. Given the prevalence of SPPL3-mediated cleavage among Golgi-resident proteins our results have important implications for the regulation of SPPL3 and its role in the organization of the Golgi glycosylation machinery.

Integrative Analysis Reveals the Potential Role and Prognostic Value of GOLM1 in Hepatocellular Carcinoma

Overexpression of Golgi membrane protein 1 (GOLM1) is closely associated with hepatocellular carcinoma (HCC) vascular invasion. How GOLM1 may be involved in angiogenesis in HCC remains unclear. We explored how GOLM1 promotes angiogenesis in HCC and potential prognostic value. Expression levels of GOLM1 in HCC patients and healthy controls were obtained from The Cancer Genome Atlas (TCGA). Differentially expressed genes (DEGs) between HCC patients and controls were compared. GOLM1 was knocked out in the HCC cell line, and RNA sequencing and DEG expression analysis were performed compared with control cells. Based on TCGA data and cell line RNA sequencing data, DEGs affected by a high expression of GOLM1 were identified. Subsequently, enrichment analysis was performed to explore the functions and pathways of the DEGs affected by a high expression of GOLM1. A relevant network analysis was built. Cox regression, genomic variance analysis scores, minimum absolute shrinkage and selection operator regression, and random forest regression models were applied to determine the best prognostic model and validated using the GSE54236 dataset from the Gene Expression Omnibus (GEO). We determined the effect of GOLM1 expression on immune cell infiltration in liver cancer. GOLM1 was overexpressed in HCC tissues compared with controls, and its level correlated with tumor purity and prognosis. 400 DEGs affected by highly expressed GOLM1 were identified in TCGA and cell line RNA sequencing data. Enrichment analysis revealed that these DEGs may be related to biological processes of oxidative stress and angiogenesis and involved in the VEGF signaling pathway and protein processing in endoplasmic reticulum. We predicted a comprehensive regulatory network in which GOLM1 activated VEGF signaling to promote HCC angiogenesis. GOLM1 may interact with E2F1 and IGF2BP3 to promote angiogenesis. GOLM1 overexpression was associated with greater immune cell infiltration. A random forest regression model was the best prognostic model. Our study reveals a potential molecular mechanism of GOLM1 in promoting HCC. We developed two prognostic models based on DEG associated with GOLM1 overexpression to help stratify HCC prognosis and improve individualized treatment.

Possible roles of Golgi protein-73 in liver diseases

Golgi protein 73 (also known as GP73 or GOLPH2) is a transmembrane glycoprotein present in the Golgi apparatus. In diseased states, GP73 is expressed by hepatocytes rather than by bile duct epithelial cells. Many studies have reported that serum GP73 (sGP73) is a marker for hepatocellular carcinoma (HCC). For HCC diagnosis, the sensitivities of sGP73 were higher than that of other markers but the specificities were lower. Considering that the concentration of GP73 is consistent with the stage of liver fibrosis and cirrhosis, some studies have implied that GP73 may be a marker for liver fibrosis and cirrhosis. Increased sGP73 levels may result from hepatic inflammatory activity. During liver inflammation, GP73 facilitates liver tissue regeneration. By summarizing the studies on GP73 in liver diseases, we wish to focus on the mechanism of GP73 in diseases.

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.

GP73 is a TBC-domain Rab GTPase-activating protein contributing to the pathogenesis of non-alcoholic fatty liver disease without obesity

The prevalence of non-obese nonalcoholic fatty liver disease (NAFLD) is increasing worldwide with unclear etiology and pathogenesis. Here, we show GP73, a Golgi protein upregulated in livers from patients with a variety of liver diseases, exhibits Rab GTPase-activating protein (GAP) activity regulating ApoB export. Upon regular-diet feeding, liver-GP73-high mice display non-obese NAFLD phenotype, characterized by reduced body weight, intrahepatic lipid accumulation, and gradual insulin resistance development, none of which can be recapitulated in liver-GAP inactive GP73-high mice. Common and specific gene expression signatures associated with GP73-induced non-obese NAFLD and high-fat diet (HFD)-induced obese NAFLD are revealed. Notably, metformin inactivates the GAP activity of GP73 and alleviates GP73-induced non-obese NAFLD. GP73 is pathologically elevated in NAFLD individuals without obesity, and GP73 blockade improves whole-body metabolism in non-obese NAFLD mouse model. These findings reveal a pathophysiological role of GP73 in triggering non-obese NAFLD and may offer an opportunity for clinical intervention.

Dysregulation of lipid metabolism and transport contribute to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Here the authors identify GP73 as a TBC-domain Rab GTPase-activating protein that regulates very low-density lipoprotein export and promotes NAFLD development in mice.

Deletion of Golgi protein 73 delayed hepatocyte proliferation of mouse in the early stages of liver regeneration

BACKGROUND AND AIM

Golgi protein 73 (GP73) is a transmembrane protein that can promote the proliferation of cancer cells. However, the roles of GP73 in the proliferation of non-malignant hepatocytes have rarely been investigated.

METHODS

The wild-type (GP73+/+ ) and GP73 gene knockout mice (GP73-/- ) were subject to 70% partial hepatectomy (PHx) to explore the involvement of GP73 in liver regeneration.

RESULTS

After PHx, a significant increase of GP73 expression was observed in GP73+/+ mouse liver. Noticeably, promoted recovery of liver mass was observed in GP73-/- mouse at Day 1 after PHx, as showed by the liver/body weight ratio. RNA sequencing revealed that genes relevant to cell cycle and inflammation response in the residual liver tissues were severely suppressed with the deletion of GP73, particularly the inactivation of NF-κB signal pathway in early phase of liver regeneration. In line with this, we do see the downregulation of cell cycle-related protein including cyclin D1, p-cyclin D1, β-catenin, as well as interleukin 6, tumor necrosis factor-α, CCl2, and CXCl10. In contrast, activation of mTOR signaling pathway was documented, accompanied with the histological hypertrophy of hepatocytes in GP73-/- mouse.

CONCLUSIONS

Golgi protein 73 deletion leads to delayed response of liver regeneration and inflammation in the early stages of liver regeneration after PHx.

Deoxycholic Acid Upregulates Serum Golgi Protein 73 through Activating NF-κB Pathway and Destroying Golgi Structure in Liver Disease

Golgi protein 73 (GP73) is upregulated in a variety of liver diseases, yet the detailed mechanism is poorly characterized. We analyzed GP73 in a retrospective cohort including 4211 patients with chronic liver disease (CLD) or hepatocellular carcinoma (HCC). The effect of deoxycholic acid (DCA) and nuclear factor-kappa B (NF-κB) on expression and release of GP73 in Huh-7 and SMMC7721 cells were studied. A mouse study was used to confirm our findings in vivo. A positive correlation was found between serum GP73 and total bile acid (TBA) in cirrhotic patients (r = 0.540, p < 0.001), higher than that in non-cirrhotic CLD (r = 0.318, p < 0.001) and HCC (r = 0.353, p < 0.001) patients. In Huh-7 and SMMC7721 cells, DCA upregulated the expression and release of GP73 in a dose- and time-dependent manner. After overexpressing NF-κB p65, the promoter activity, GP73 messenger RNA (mRNA) level, and supernatant GP73 level were increased. The promotion effect of DCA on GP73 release was attenuated after inhibiting the NF-κB pathway. Mutating the binding sites of NF-κB in the sequence of the GP73 promoter led to a declined promoting effect of DCA on GP73. The upregulation role of DCA in GP73 expression through the NF-κB pathway was confirmed in vivo. In addition, exposure to DCA caused disassembly of Golgi apparatus. In summary, DCA upregulates the expression and release of GP73 via activating the NF-κB pathway and destroying the Golgi structure.

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.

Recent advances of GOLM1 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common liver malignancies and is a leading cause of cancer-related deaths. Most HCC patients are diagnosed at an advanced stage and current treatments show poor therapeutic efficacy. It is particularly urgent to explore early diagnosis methods and effective treatments of HCC. There are a growing number of studies that show GOLM1 is one of the most promising markers for early diagnosis and prognosis of HCC. It is also involved in immune regulation, activation and degradation of intracellular signaling factors and promotion of epithelial-mesenchymal transition. GOLM1 can promote HCC progression and metastasis. The understanding of the GOLM1 regulation mechanism may provide new ideas for the diagnosis, monitoring and treatment of HCC.

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.

Tumor Microenvironment Regulation by the Endoplasmic Reticulum Stress Transmission Mediator Golgi Protein 73 in Mice

The unfolded protein response (UPR) signal in tumor cells activates UPR signaling in neighboring macrophages, which leads to tumor-promoting inflammation by up-regulating UPR target genes and proinflammatory cytokines. However, the molecular basis of this endoplasmic reticulum (ER) stress transmission remains largely unclear. Here, we identified the secreted form of Golgi protein 73 (GP73), a Golgi-associated protein functional critical for hepatocellular carcinoma (HCC) growth and metastasis, is indispensable for ER stress transmission. Notably, ER stressors increased the cellular secretion of GP73. Through GRP78, the secreted GP73 stimulated ER stress activation in neighboring macrophages, which then released cytokines and chemokines involved in the tumor-associated macrophage (TAM) phenotype. Analysis of HCC patients revealed a positive correlation of GP73 with glucose-regulated protein 78 (GRP78) expression and TAM density. High GP73 and CD206 expression was associated with poor prognosis. Blockade of GP73 decreased the density of TAMs, inhibited tumor growth, and prolonged survival in two mouse HCC models. Conclusion: Our findings provide insight into the molecular mechanisms of extracellular GP73 in the amplification and transmission of ER stress signals.

Golgi membrane protein GP73 modified-liposome mediates the antitumor effect of survivin promoter-driven HSVtk in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of cancer worldwide, and there is currently no effective therapeutic strategy in clinical practice. Gene therapy has great potential for decreasing tumor-induced mortality but has been clinically limited because of the lack of tumor-specific targets and insufficient gene transfer. The study of targeted transport of therapeutic genes in HCC treatment seems to be very important. In this study, we evaluated a gene therapy approach targeting HCC using the herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV) suicide gene system in HCC cell lines and in an in vivo human HCC xenograft mouse model. GP73-modified liposomes targeted gene delivery to the tumor tissue, and the survivin promoter drove HSVtk expression in the HCC cells. Our results showed that the survivin promoter was specifically activated in tumor cells and HSVtk was expressed selectively in tumor cells. Combined with GCV treatment, HSVtk expression resulted in suppression of HCC cell proliferation via enhancing apoptosis. Moreover, tail vein injection of GP73-HSVtk significantly suppressed the growth of xenograft tumors through an apoptosis-dependent pathway and extended the survival of tumor-bearing mice without damaging the mice liver functions. Taken together, this study demonstrates an effective cancer-specific gene therapy strategy using the herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV) suicide gene system for HCC that can be further developed for future clinical trials.

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 GP73 - An Additional Biochemical Marker for Liver Inflammation in Chronic HBV Infected Patients with Normal or Slightly Raised ALT

This study aimed to assess the feasibility of GP73 as a diagnostic marker for liver inflammation and fibrosis in chronic HBV patients with normal or slightly raised ALT (<2 ULN) and to develop models based on GP73 and other biochemical parameters to improve diagnostic accuracy. Serum GP73 levels were analyzed in 220 chronic HBV patients with normal or slightly raised ALT who underwent liver biopsy. The results showed that the area under the receiver operating characteristic (ROC) curve (AUC) was 0.806 for predicting significant liver inflammation (≥G2), while it was 0.742 for predicting significant fibrosis (≥S2). These results suggest that GP73 has higher diagnostic value for liver inflammation than liver fibrosis. Combining GP73, AST and ALB, as a diagnostic model for predicting significant liver inflammation, resulted in superior diagnostic performance over GP73 alone (AUC value increased from 0.806 to 0.854, z = 2.299, P = 0.021). By applying this diagnostic model, over 80% of chronic HBV patients with normal or slightly raised ALT will be correctly identified and hence avoid delay in diagnosis and treatment. In conclusion, GP73 would be an additional serum marker for predicting liver inflammation and fibrosis in chronic HBV patients with normal or slightly raised ALT.

MicroRNA-143 regulates cell migration and invasion by targeting GOLM1 in cervical cancer

Accumulated research has revealed that the abnormal expression of microRNAs play a crucial role in tumorigenesis, potentially serving as therapeutic biomarkers in multiple tumors including cervical cancer. However, the expression level, biological role and the underlying mechanism of miRNA-143 in cervical cancer remain unclear. In the current study, we analyzed the miRNA-143 and golgi membrane protein 1 (GOLM1) expression in cervical cancer tissues and cells to explore their effects on cervical cancer occurrence and metastasis. Reverse transcription-quantitative PCR (RT-qPCR) was used to detect the miRNA-143 expression in cervical cancer tissues and cells. Following transfection, cell Transwell assays, western blot analysis and luciferase reporter assays were carried out in human cervical cancer cells. Results demonstrated that the miRNA-143 expression was dramatically decreased in both cervical cancer tissue samples and cells in contrast with the control group. We also found that the miRNA-143 expression negatively correlated with the GOLM1 expression in cervical cancer tissues and miRNA-143 inhibited cell invasion and migration via targeting GOLM1 in cervical cancer.

The Clinical Significance of GP73 in Immunologically Mediated Chronic Liver Diseases: Experimental Data and Literature Review

There is significant void in establishing validated non-invasive surrogate biomarkers of liver fibrosis/cirrhosis in chronic liver diseases (CLD). Golgi protein 73 (GP73) has been suggested as a potential serum marker for the diagnosis of hepatocellular carcinoma (HCC). However, significant background of cirrhosis could have accounted for the elevation of serum GP73 in HCC. In this study, we have taken advantage of a well-defined extensive cohort of 3044 patients with either compensated cirrhosis (n = 1247), decompensated cirrhosis (n = 841) or pre-cirrhotic CLD (n = 956) and our ability to quantify serum GP73 to define the potential of serum GP73 as a biomarker of liver cirrhosis/fibrosis in CLD. The diagnostic value of GP73 was compared with aspartate aminotransferase-to-platelet ratio index (APRI), fibrosis index based on four factors (FIB-4) and liver stiffness measurement (LSM). Immunohistochemical analysis was performed to measure hepatic GP73 expression. Receiver operating characteristic curve analysis demonstrated that serum GP73 had a good diagnostic potential for compensated cirrhosis regardless of etiology. The diagnostic performance of GP73 is better than APRI, FIB-4 and similar with LSM, especially in patients with severe inflammation, steatosis and cholestasis. Notably, in patients of autoimmune liver diseases, non-alcoholic fatty liver disease and viral hepatitis, serum GP73 also exhibited diagnostic value for advanced fibrosis as well as cirrhosis. Furthermore, there is also a gradual increase in GP73 expression with disease progression from mild fibrosis to cirrhosis. In conclusion, GP73 is an effective and reliable serological marker for the diagnosis of advanced fibrosis and prediction of appearance of cirrhosis.

Expression and correlation of CD44 and GP73 in cerebroma tissues

Cerebroma, a nervous system tumor located in the cranial cavity, seriously affects health and may even become life-threatening. The aim of the study was to investigate and discuss the expression levels of cluster of differentiation 44 (CD44) and Golgi protein 73 (GP73) in different types of cerebroma tissues and to study the correlations of CD44 and GP73. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA expression levels of CD44 and GP73 in four kinds of cerebroma. The immunohistochemical streptavidin-biotin complex (SABC) method was applied to measure the expression levels of CD44 and GP73 in different types of cerebroma. Subsequently, immunofluorescence and western blot analysis were performed to detect the expression levels of CD44 and GP73 in four kinds of cerebroma tissues. Statistical Product and Service Solutions (SPSS) 17.0 software was used to analyze the differences in CD44 and GP73 expression levels of the four kinds of cerebroma tissues and normal brain tissues. Transcription of CD44 and GP73 mRNAs was detected in the four kinds of cerebroma tissues, and CD44 and GP73 proteins were expressed. The immunohistochemical results revealed that the expression levels of CD44 and GP73 in the four kinds of cerebroma were significantly increased compared with those in normal tissues. The immunofluorescence results indicated that both CD44 and GP73 were expressed in four kinds of cerebroma, and the expression of CD44 was higher than that of GP73. The results of analysis of variance showed that the differences in CD44 and GP73 expression levels in the four kinds of cerebroma tissues and normal brain tissues were statistically significant (P<0.01). The results show that the expression levels of CD44 and GP73 are obviously upregulated in four kinds of cerebroma tissues, suggesting that CD44 and GP73 have great value for cerebroma research and can provide a new direction for clinical study as well as the diagnosis and treatment of cerebroma.

GP73 promotes invasion and metastasis of bladder cancer by regulating the epithelial-mesenchymal transition through the TGF-β1/Smad2 signalling pathway

This study investigated the effects of Golgi membrane protein 73 (GP73) on the epithelial-mesenchymal transition (EMT) and on bladder cancer cell invasion and metastasis through the TGF-β1/Smad2 signalling pathway. Paired bladder cancer and adjacent tissue samples (102) and normal bladder tissue samples (106) were obtained. Bladder cancer cell lines (T24, 5637, RT4, 253J and J82) were selected and assigned to blank, negative control (NC), TGF-β, thrombospondin-1 (TSP-1), TGF-β1+ TSP-1, GP73-siRNA-1, GP73-siRNA-2, GP73-siRNA-1+ TSP-1, GP73-siRNA-1+ pcDNA-GP73, WT1-siRNA and WT1-siRNA + GP73-siRNA-1 groups. Expressions of GP73, TGF-β1, Smad2, p-Smad2, E-cadherin and vimentin were detected using RT-qPCR and Western blotting. Cell proliferation, migration and invasion were determined using MTT assay, scratch testing and Transwell assay, respectively. Compared with the blank and NC groups, levels of GP73, TGF-β1, Smad2, p-Smad2, N-cadherin and vimentin decreased, and levels of WT1 and E-cadherin increased in the GP73-siRNA-1 and GP73-siRNA-2 groups, while the opposite results were observed in the WT1 siRNA, TGF-β, TSP-1 and TGF-β + TSP-1 groups. Cell proliferation, migration and invasion notably decreased in the GP73-siRNA-1 and GP73-siRNA-2 groups in comparison with the blank and NC groups, while in the WT1 siRNA, TGF-β, TSP-1 and TGF-β + TSP-1 groups, cell migration, invasion and proliferation showed the reduction after the EMT. These results suggest that GP73 promotes bladder cancer invasion and metastasis by inducing the EMT through down-regulating WT1 levels and activating the TGF-β1/Smad2 signalling pathway.

Algorithm of Golgi protein 73 and liver stiffness accurately diagnoses significant fibrosis in chronic HBV infection

BACKGROUND & AIMS

Serum Golgi protein 73 (GP73) is a potential biomarker for fibrosis assessment. We aimed to develop an algorithm based on GP73 and liver stiffness (LS) for further improvement of accuracy for significant fibrosis in patients with antiviral-naïve chronic hepatitis B virus (HBV) infection.

METHODS

Diagnostic accuracy evaluation of GP73 and development of GP73-LS algorithm was performed in training cohort (n = 267) with an independent cohort (n = 133) for validation.

RESULTS

A stepwise increasing pattern of serum GP73 was observed across fibrosis stages in patients with antiviral-naïve chronic HBV infection. Serum GP73 significantly correlated (rho = 0.48, P < .001) with fibrosis stage and was an independent predictor for the presence of significant fibrosis (OR, 95%CI: 1.02, 1.01-1.03, per increase in 1 ng/mL, P < .001). Both LS (AUROC, 95%CI: 0.82, 0.77-0.87, accuracy: 74.7%) and GP73 (AUROC, 95%CI: 0.76, 0.71-0.82, accuracy: 71.5%) well-predicted significant fibrosis and outperformed APRI (AUROC, 95%CI: 0.69, 0.63-0.76, accuracy: 66%) and FIB-4 (AUROC, 95%CI: 0.66, 0.60-0.73, accuracy: 63.6%). Using GP73-LS algorithm, GP73 < 63 in agreement with LS < 8.5 provided accuracy of 81.7% to excluded significant fibrosis. GP73 ≥ 63 in agreement with LS ≥ 8.5 provided accuracy of 93.3% to confirm significant fibrosis. Almost 64% or 68% of patients in the training or validation cohort could be accurately classified.

CONCLUSIONS

Serum GP73 is a robust biomarker for significant fibrosis diagnosis. GP73-LS algorithm provided better diagnostic accuracy than currently available approaches. More than 60% antiviral naïve CHB patients could use this algorithm without resorting to liver biopsy.

Serum Golgi protein 73 is a prognostic rather than diagnostic marker in hepatocellular carcinoma

Serum Golgi protein 73 (sGP73) is a candidate diagnostic biomarker for hepatocellular carcinoma (HCC). However, current evidence of its diagnostic value is conflicting, primarily due to the small sample sizes of previous studies, and its prognostic role in HCC also remains unclear. In the present study, sGP73 levels in 462 patients with HCC, 186 patients with liver cirrhosis, and 83 healthy controls were evaluated using ELISA, and it was identified that the median sGP73 levels were significantly higher in the HCC (18.7 ng/ml) and liver cirrhosis (18.5 ng/ml) patients than in the healthy controls (0 ng/ml; both P<0.001); however, the levels did not significantly differ between the HCC and liver cirrhosis groups (P=0.632). sGP73 had an inferior sensitivity and specificity for HCC diagnosis (27.79 and 77.96%, respectively) compared with α-fetoprotein (57.36 and 90.96%, respectively; P<0.001). In the HCC group, a high level of sGP73 was associated with aggressive clinicopathological features and independently predicted poor overall survival (OS) time (P<0.001). Additionally, in patients with resectable HCC, a high level of sGP73 was associated with significantly decreased disease-free survival (P<0.001) and OS (P=0.039) times compared with a low level of sGP73. This study demonstrated that sGP73 is unsuitable as a diagnostic marker for the early detection of HCC; however, it is an independent negative prognostic marker, providing a novel risk stratification factor and a potential therapeutic molecular target for HCC.

Manganese-induced trafficking and turnover of GPP130 is mediated by sortilin

By binding and directing the cycling Golgi protein GPP130 to lysosomes, the sorting receptor sortilin mediates the manganese-induced GPP130 down-regulation that protects against Shiga toxicosis.

Elevated, nontoxic doses of manganese (Mn) protect against Shiga toxin-1–induced cell death via down-regulation of GPP130, a cycling Golgi membrane protein that serves as an endosome-to-Golgi trafficking receptor for the toxin. Mn binds to GPP130 in the Golgi and causes GPP130 to oligomerize/aggregate, and the complexes are diverted to lysosomes. In fact, based on experiments using the self-interacting FM domain, it appears generally true that aggregation of a Golgi protein leads to its lysosomal degradation. How such oligomers are selectively sorted out of the Golgi is unknown. Here we provide evidence that Mn-induced exit of GPP130 from the trans-Golgi network (TGN) toward lysosomes is mediated by the sorting receptor sortilin interacting with the lumenal stem domain of GPP130. In contrast, FM-induced lysosomal trafficking of the Golgi protein galactosyltransferase was sortilin independent and occurred even in the absence of its native lumenal domain. Thus sortilin-dependent as well as sortilin-independent sorting mechanisms target aggregated Golgi membrane proteins for lysosomal degradation.

GP73 represses host innate immune response to promote virus replication by facilitating MAVS and TRAF6 degradation

Hepatitis C virus (HCV) infection is a leading cause of chronic liver diseases and hepatocellular carcinoma (HCC) and Golgi protein 73 (GP73) is a serum biomarker for liver diseases and HCC. However, the mechanism underlying GP73 regulates HCV infection is largely unknown. Here, we revealed that GP73 acts as a novel negative regulator of host innate immunity to facilitate HCV infection. GP73 expression is activated and correlated with interferon-beta (IFN-β) production during HCV infection in patients’ serum, primary human hepatocytes (PHHs) and human hepatoma cells through mitochondrial antiviral signaling protein (MAVS), TNF receptor-associated factor 6 (TRAF6) and mitogen-activated protein kinase kinase/extracellular regulated protein kinase (MEK/ERK) pathway. Detailed studies revealed that HCV infection activates MAVS that in turn recruits TRAF6 via TRAF-interacting-motifs (TIMs), and TRAF6 subsequently directly recruits GP73 to MAVS via coiled-coil domain. After binding with MAVS and TRAF6, GP73 promotes MAVS and TRAF6 degradation through proteasome-dependent pathway. Moreover, GP73 attenuates IFN-β promoter, IFN-stimulated response element (ISRE) and nuclear factor κB (NF-κB) promoter and down-regulates IFN-β, IFN-λ1, interleukin-6 (IL-6) and IFN-stimulated gene 56 (ISG56), leading to the repression of host innate immunity. Finally, knock-down of GP73 down-regulates HCV infection and replication in Huh7-MAVSR cells and primary human hepatocytes (PHHs), but such repression is rescued by GP73m4 (a mutant GP73 resists to GP73-shRNA#4) in Huh7-MAVSR cells, suggesting that GP73 facilitates HCV infection. Taken together, we demonstrated that GP73 acts as a negative regulator of innate immunity to facilitate HCV infection by interacting with MAVS/TRAF6 and promoting MAVS/TRAF6 degradation. This study provides new insights into the mechanism of HCV infection and pathogenesis, and suggests that GP73 is a new potential antiviral target in the prevention and treatment of HCV associated diseases.

Golgi protein 73 (GP73) is a serum biomarker for liver diseases and hepatocellular carcinoma (HCC). In this study, the authors reveal that GP73 acts as a novel negative regulator of host innate immunity to facilitate hepatitis C virus (HCV) infection. GP73 expression is activated and correlated with IFN-β production during HCV infection in patients’ serum, primary human hepatocytes (PHHs) and human hepatoma cells through mitochondrial antiviral signaling protein (MAVS), TNF receptor-associated factor 6 (TRAF6) and MEK/ERK pathway. They further demonstrate that during viral infection, MAVS recruits TRAF6 that subsequently directly binds with GP73. After binding with MAVS and TRAF6, GP73 promotes MAVS and TRAF6 degradation. Moreover, GP73 attenuates IFN-β promoter, IFN-stimulated response element (ISRE) and NF-κB promoter and down-regulates IFN-β, IFN-λ1, interleukin-6 (IL-6) and IFN-stimulated gene 56 (ISG56), leading to the repression of host innate immunity and the facilitation of virus infection. These results reveal a novel mechanism by which GP73 acts as a novel negative regulator of host innate immunity to facilitate virus infection and also provide new insights into the therapeutic design of anti-HCV drugs.

Evaluation of prothrombin induced by vitamin K absence, macrophage migration inhibitory factor and Golgi protein-73 versus alpha fetoprotein for hepatocellular carcinoma diagnosis and surveillance

Hepatocellular carcinoma (HCC) represents a challenging malignancy of worldwide importance. It is the third most common cause of cancer-related death globally as most patients present with unresectable disease. Alpha-fetoprotein (AFP) is the widely and solely used biomarker for HCC diagnosis; yet, its usefulness is hampered by low sensitivity and specificity. We aimed to identify more sensitive biomarkers for HCC diagnosis and a surveillance algorithm that may facilitate early detection of HCC. A total of 305 Egyptian and Saudi participants grouped as healthy controls, cancer controls, benign hepatic lesions, chronic viral hepatitis and HCC were included. Serum AFP, prothrombin induced by vitamin K absence-II (PIVKA-II), macrophage migration inhibitory factor (MIF) and Golgi protein-73 (GP-73) levels were quantitated by enzyme immunoassay. Significantly higher levels of GP-73 and PIVKA-II were detected in the HCC group than in all other groups, while MIF showed a highly significant increase in HCC from all groups except the cancer control group. The HCC group showed no significant difference between the studied biomarkers and the type of chronic viral hepatitis. On the basis of multiple ROC curve analyses, GP-73 and PIVKA-II showed the highest sensitivity and specificity for surveillance and diagnosis. In conclusion, PIVKA-II and GP-73 offer an effective approach for early HCC diagnosis and surveillance of high-risk groups with a higher accuracy than AFP. MIF may serve as a promising screening tumor marker for the detection of gastrointestinal tract (GIT) malignancy.

Golgi protein 73 activation of MMP-13 promotes hepatocellular carcinoma cell invasion

Golgi Protein 73 (GP73) is a serum biomarker for hepatocellular carcinoma (HCC), however its role in HCC is not clear. We report that GP73 promotes cell invasion, the hallmark of malignancy, through the upregulation of matrix metalloproteinase-13 (MMP-13). GP73 enhances MMP-13 expression through cAMP responsive element binding protein (CREB)-mediated transcription activation. Levels of GP73 and MMP-13 are increased and positively correlated in human HCC tissues. Augmented MMP-13 potentiates HCC cell metastasis. Thus, the GP73-CREB-MMP-13 axis potentiates cancer cell invasion and may be a target for HCC treatment.

Aberrant expression of Golgi protein 73 is indicative of a poor outcome in hepatocellular carcinoma

Golgi protein 73 (GP73), a resident Golgi type-II membrane protein, is often upregulated in hepatocytes. In the present study, shRNA-mediated suppression of GP73 expression in hepatocellular carcinoma (HCC) cell lines (MHCC97H, HCCLM3) resulted in a significant inhibition of cell motility and invasion and also led to the regression of epithelial-mesenchymal transition phenotypes. In contrast, overexpression of GP73 in the SMMC7721 cell line retrieved the expression of EMT markers, and promoted cell motility and invasion. High expression of GP73 was also found in HCC tissues with metastasis, as detected by western blot and immunohistochemistry analyses. Kaplan-Meier survival analysis showed that the survival of patients with high GP73 expression was significantly poorer than that of patients with low GP73 expression (p=0.027). Our findings demonstrated an important role of GP73 in HCC metastasis, and indicated that GP73 is a candidate target for HCC therapy.

Golgi phosphoprotein 2 (GOLPH2) is a novel bile acid-responsive modulator of oesophageal cell migration and invasion

BACKGROUND

The aetiology of Barrett's oesophagus (BO) and oesophageal cancer is poorly understood. We previously demonstrated that Golgi structure and function is altered in oesophageal cancer cells. A Golgi-associated protein, GOLPH2, was previously established as a tissue biomarker for BO. Cellular functions for GOLPH2 are currently unknown, therefore in this study we sought to investigate functional roles for this Golgi-associated protein in oesophageal disease.

METHODS

Expression, intracellular localisation and secretion of GOLPH2 were identified by immunofluorescence, immunohistochemistry and western blot. GOLPH2 expression constructs and siRNA were used to identify cellular functions for GOLPH2.

RESULTS

We demonstrate that the structure of the Golgi is fragmented and the intracellular localisation of GOLPH2 is altered in BO and oesophageal adenocarcinoma tissue. GOLPH2 is secreted by oesophageal cancer cells and GOLPH2 expression, cleavage and secretion facilitate cell migration and invasion. Furthermore, exposure of cells to DCA, a bile acid component of gastric refluxate and known tumour promoter for oesophageal cancer, causes disassembly of the Golgi structure into ministacks, resulting in cleavage and secretion of GOLPH2.

CONCLUSIONS

This study demonstrates that GOLPH2 may be a useful tissue biomarker for oesophageal disease. We provide a novel mechanistic insight into the aetiology of oesophageal cancer and reveal novel functions for GOLPH2 in regulating tumour cell migration and invasion, important functions for the metastatic process in oesophageal cancer.

The microRNA-23b/27b/24-1 cluster is a disease progression marker and tumor suppressor in prostate cancer

Our recent study of microRNA (miRNA) expression signatures in prostate cancer (PCa) has revealed that all members of the miR-23b/27b/24-1 cluster are significantly downregulated in PCa tissues. The aim of this study was to investigate the effectiveness of these clustered miRNAs as a disease progression marker and to determine the functional significance of these clustered miRNAs in PCa. Expression of the miR-23b/27b/24-1 cluster was significantly reduced in PCa tissues. Kaplan-Meier survival curves showed that low expression of miR-27b predicted a short duration of progression to castration-resistant PCa. Gain-of-function studies using mature miR-23b, miR-27b, and miR-24-1 significantly inhibited cell proliferation, migration and invasion in PCa cells (PC3 and DU145). To identify the molecular targets of these miRNAs, we carried out gene expression and in silico database analyses. GOLM1 was directly regulated by miR-27b in PCa cells. Elucidation of the molecular targets and pathways regulated by the tumor-suppressive microRNAs should shed light on the oncogenic and metastatic processes in PCa.

Effect of Golgi phosphoprotein 2 (GOLPH2/GP73) on autophagy in human hepatocellular carcinoma HepG2 cells

This study aims to investigate the effect of Golgi Protein 73 (GP73) on autophagy in human hepatoma line cells HepG2. We investigated the functional effects of GP73 on autophagy in hepatoma cell line HepG2 using immunofluoscence staining, Western blotting and real-time PCR. Our data showed that specific small interference RNA (siRNA) notably induced formation of autophagic vacuoles. In addition, upregulation of GP73 significantly inhibited formation of starvation-induced LC3-positive structures. We provide the first experimental evidence to show that GP73 may play an important role in the inhibitory regulation of autophagy. Therefore, our data suggest a new molecular mechanism for GP73-related hepatoma progression.

Serum Golgi protein 73 levels and liver pathological grading in cases of chronic hepatitis B

The present study was designed to assess the correlation between serum Golgi protein 73 (GP73) and liver pathological grading and staging in patients with chronic hepatitis B (CHB). Two hundred and fifty‑three patients with chronic hepatitis B virus (HBV) infections were enrolled in the present study. All patients received a serum GP73 test, and 91 CHB patients underwent liver biopsy. GP73 expression in liver tissue was assessed by immunohistochemical analysis. The results indicated that serum GP73 levels were positively correlated with disease progression in patients with chronic HBV infection (r=0.677). There was no significant difference in serum GP73 levels between hepatitis B e antigen‑positive and ‑negative patients (P>0.05). There were also no significant differences in serum GP73 levels among specimens with varying HBV DNA contents (P>0.05). Serum GP73 levels were positively correlated with increased liver pathological grading (r=0.737) and staging (r=0.692), and immunohistochemical analysis indicated that GP73 protein expression increased concurrently with liver pathological grading and staging. In conclusion, serum GP73 was found to be correlated with liver pathological grading and staging in patients with CHB, and may be an effective indicator for the evaluation of disease progression. However, serum GP73 levels were not associated with HBV replication.

Serum gp73 is also a biomarker for diagnosing cirrhosis in population with chronic HBV infection

OBJECTIVES

To clarify the role of Golgi membrane glycoprotein 73 (gp73) in evaluating the progression of chronic hepatitis B virus (HBV) infection.

DESIGN AND METHODS

Participants included 958 controls, 421 chronic hepatitis B, 944 hepatic cirrhosis, and 127 hepatocellular carcinoma (HCC) patients. All the patients, with the exception of the controls, were diagnosed HBsAg positive. Serum biomarkers, including gp73, alpha-fetoprotein (AFP), alpha-l-fucosidase, and Lens culinaris agglutinin-reactive fraction of AFP, were determined.

RESULTS

The patients with Hepatic cirrhosis gp73 levels over 150 ng/mL had an odds ratio of 3.21 (95% CI: 2.07-5.00). In hepatic cirrhosis patients, serum gp73 correlated with the Child-Pugh score. gp73 is a marker for diagnosing cirrhosis in the hepatitis populations. When the cut-off was set at 75.5 ng/mL, the sensitivity, specificity, and AUC were 75.6% (95% CI: 71.30%-79.62%), 60.3% (95% CI: 56.95%-63.63%) and 0.72 (95% CI: 0.69-0.75), respectively.

CONCLUSION

The variation trend of gp73 in chronic liver disease may indicate that monitoring of serum gp73 is helpful to diagnose cirrhosis in population with chronic HBV infection.

Manganese induces oligomerization to promote down-regulation of the intracellular trafficking receptor used by Shiga toxin

Manganese down-regulates the Shiga toxin receptor GPP130, which protects against lethal toxin doses. This study reveals a major aspect of the mechanism. Manganese binds GPP130, inducing GPP130 oligomerization, which is required and sufficient to redirect GPP130 out of the Golgi toward lysosomes.

Manganese (Mn) protects cells against lethal doses of purified Shiga toxin by causing the degradation of the cycling transmembrane protein GPP130, which the toxin uses as a trafficking receptor. Mn-induced GPP130 down-regulation, in addition to being a potential therapeutic approach against Shiga toxicosis, is a model for the study of metal-regulated protein sorting. Significantly, however, the mechanism by which Mn regulates GPP130 trafficking is unknown. Here we show that a transferable trafficking determinant within GPP130 bound Mn and that Mn binding induced GPP130 oligomerization in the Golgi. Alanine substitutions blocking Mn binding abrogated both oligomerization of GPP130 and GPP130 sorting from the Golgi to lysosomes. Further, oligomerization was sufficient because forced aggregation, using a drug-controlled polymerization domain, redirected GPP130 to lysosomes in the absence of Mn. These experiments reveal metal-induced oligomerization as a Golgi sorting mechanism for a medically relevant receptor for Shiga toxin.

Evaluation of α-fetoprotein-L3 and Golgi protein 73 detection in diagnosis of hepatocellular carcinoma

Aim of the study

Hepatocellular carcinoma (HCC) is common throughout the world. Most HCCs are diagnosed at an advanced stage. There is an urgent need to find new methods for screening and surveillance of individuals at risk for HCC. The aim of this study was to evaluate serum α-fetoprotein (AFP)-L3 and serum Golgi protein 73 (GP73) detection in diagnosis of HCC with different AFP concentration.

Material and methods

One hundred and eighty one patients were involved, including 102 with HCC and 79 with benign liver disease. The serum AFP-L3 and GP73 was measured by a liquid-phase binding assay and quantitative enzyme-linked immunosorbent assay, respectively.

Results

Of the 102 HCC patients, 53 were positive for AFP, 77 were positive for AFP-L3, and 79 were positive for GP73. The maximum area under the curve for AFP-L3% and for GP73 was significantly different from the AUC of 0.5525 for total AFP (p < 0.01). AFP-L3% was not detected for AFP < 20 ng/ml. However, elevated GP73 was detected in 87.50% of the patients. In the HCC patients with total AFP 20–400 ng/ml, elevated AFP-L3 was detected in 26 patients, whereas in 23 patients elevated GP73 could be detected. In the HCC patients with a total AFP > 400 ng/ml, AFP-L3% > 10% was present in 96.23%, and GP73 was detected in 87.50%.

Conclusions

The determination of AFP-L3% and GP73 in combination with AFP can increase the sensitivity and specificity in diagnosis of HCC. α-fetoprotein-L3% and GP73, in combination with AFP, are useful biomarkers to confirm the diagnosis of HCC.

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

Although Golgi protein 73 (GP73) has been widely evaluated for diagnosing hepatocellular carcinoma (HCC) and other liver diseases in recent decade, its serum profile of patients with hepatitis B virus (HBV)-associated acute-on-chronic liver failure (HBV-ACLF) is still unknown. This study was designed to evaluate the serum levels of GP73 in patients with HBV-ACLF. The participants included 200 apparently healthy controls; 200 patients with chronic hepatitis B (CHB); 200 patients with HCC; 210 patients with HBV-ACLF, in which 29 HBV-ACLF patients were followed up for 3 months. All patients were Hepatitis B virus surface antigen (HBsAg) positive. The concentrations of GP73 in patients with HBV-ACLF (285.3 ± 128.5 ng/mL) were markedly higher than those HCC patients (159.1 ± 105.8 ng/mL), CHB patients (64.65 ± 44.99 ng/mL), and healthy controls (35.37 ± 12.41 ng/mL). When the cut-off value was set at 182.1 ng/mL, the sensitivity and specificity of HBV-ACLF diagnosis were 77.62% (95% confidence interval [CI]: 71.37%-83.07%) and 95.50% (95% CI: 92.27%-98.26%), respectively. If serum GP73 concentration was still above 361.6 ng/mL after 14 days of follow-up, the patient's prognosis may be depressed. Serum GP73 may be used to diagnosis HBV-ACLF in population with chronic HBV infections.

The tumor-suppressive microRNA-143/145 cluster inhibits cell migration and invasion by targeting GOLM1 in prostate cancer

Our recent study of microRNA (miRNA) expression signature of prostate cancer (PCa) has revealed that the microRNA-143/145 (miR-143/145) cluster is significantly downregulated in cancer tissues, suggesting that these cluster miRNAs are candidate tumor suppressors. The aim of this study was to investigate the functional significance of the miR-143/145 cluster in PCa cells and to identify novel targets regulated by these cluster miRNAs in PCa. Restoration of miR-143 or miR-145 in PCa cell lines (PC3 and DU145) revealed that these miRNAs significantly inhibited cancer cell migration and invasion. Gene expression data and in silico analysis demonstrated that Golgi membrane protein 1 (GOLM1) resembling a type II golgi transmembrane protein was a potential target of miR-143/145 cluster target gene. Gene expression studies and luciferase reporter assays showed that GOLM1 was directly regulated by the miR-143/145 cluster. Silencing of GOLM1 resulted in significant inhibition of cell migration and invasion in PCa cells. Furthermore, the expression of GOLM1 was upregulated in cancer tissues by immunohistochemistry. Loss of the tumor-suppressive miR-143/145 cluster enhanced cancer cell migration and invasion in PCa through directly regulating GOLM1. Our data on target genes regulated by the tumor-suppressive miR-143/145 cluster provide new insights into the potential mechanisms of PCa oncogenesis and metastasis.

Evaluation of circulating Transforming growth factor-beta1, Glypican-3 and Golgi protein-73 mRNAs expression as predictive markers for hepatocellular carcinoma in Egyptian patients

Hepatocellular carcinoma (HCC) incidence is fast-growing especially in countries highly prevalent with viral hepatitis. Its poor prognosis has driven the research toward the discovery of sensitive markers for early detection. We investigated the usefulness of serum Transforming growth factor-beta1 (TGF-β1), Glypican-3 (GPC3), and Golgi protein-73 (GP73) mRNAs as early biomarkers in HCC Egyptian patients chronically infected with hepatitis C virus (HCV) in comparison with serum alpha-fetoprotein (AFP). Using semi-quantitative RT-PCR and densitometry analysis, circulating TGF-β1, GPC3, and GP73 mRNAs expressions were estimated in 15 healthy adults, 15 chronic HCV (CHC) patients and 25 HCC patients. Serum GP73 expression percentage in HCC group was significantly higher than controls (100 vs. 40 %, P ≤ 0.001) and when compared to elevated serum AFP levels (100 vs. 36 %, P ≤ 0.001). TGF-β1 and GP73 expression means were also higher in HCC patients than controls and CHC patients (P < 0.05). GPC3 expression showed higher frequency in CHC patients compared to HCC group (80 vs. 28 %, P = 0.0016). According to the study cutoffs, serum TGF-β1 and GP73 mRNAs showed 60 and 96 % sensitivities for HCC diagnosis with 100 and 95 % specificities, respectively. Furthermore, elevated GP73 mRNA expression levels in early HCC were significantly increased compared to those of TGF-β1 mRNA and to high serum AFP (92.3 vs. 53.8 and 23.1 %; P = 0.03 and 0.0004, respectively). In conclusion, circulating TGF-β1 and GP73 mRNAs could be useful biomarkers for HCV-induced HCC diagnosis. Moreover, serum GP73 mRNA is sensitive for early cancer detection than AFP and TGF-β1 mRNA. However, these results need further validation studies.

Gradually increased Golgi protein 73 expression in the progression of benign liver diseases to precancerous lesions and hepatocellular carcinoma correlates with prognosis of patients

AIM

Serum Golgi protein 73 (sGP73) is a novel biomarker for hepatocellular carcinoma (HCC). However, there are few reports on the pattern of GP73 expression in the progression of benign liver diseases to precancerous lesions and HCC. This study aimed to investigate GP73 expression and its correlation with clinicopathological parameters.

METHODS

Tissue GP73 (tGP73) levels were detected in specimens of group A (n = 186) including HCC, peritumoral tissue (PTL), high/low-grade hepatic atypical hyperplasia (AH), chronic hepatitis B (CHB) and normal controls (NC) by immunohistochemistry, and GP73 expression in group B (n = 159) and group C (n = 16) were detected by reverse transcription polymerase chain reaction and western blot, respectively. sGP73 levels were detected in subjects of group D (n = 287) by enzyme-linked immunoassay.

RESULTS

GP73 expression increased gradually from NC, CHB, PTL to high-grade AH and HCC at both protein and mRNA levels (P < 0.05), while sGP73 in the HCC group was lower than in the liver cirrhosis (LC) group (P < 0.001). Both tGP73 and sGP73 levels were negatively associated with tumor size and tumor-node-metastasis stage, and tGP73 levels were positively associated with tumor differentiation. The high-tGP73 group showed significantly better overall and disease-free survival than the low-tGP73 group (P = 0.008, P = 0.018). Multivariate analysis revealed that the tGP73 level was an independent prognostic factor for HCC, but not sGP73.

CONCLUSION

GP73 expression pattern suggests that the regulatory mechanism of GP73 is related to the progression of chronic liver diseases. Furthermore, a high level of tGP73 is a favorable prognostic factor for HCC.

GP73 is a potential marker for evaluating AIDS progression and antiretroviral therapy efficacy

Golgi protein-73 (GP73) is upregulated in cancers and viral infections; however, its role in human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) remains undetermined. GP73 was evaluated as a biomarker of HIV progression and AIDS treatment efficacy. Forty-eight HIV patients (≤ 350 CD4 + T cells/μL) undergoing highly active antiretroviral therapy (HAART group) and 18 HIV patients expected to undergo HAART within 9 months (>350 CD4 + T cells/μL) (control group) were enrolled in a prospective, single center, cohort study from May 2009 to Jun 2012. Blood aspartate aminotransferase, alanine aminotransferase (ALT), cholesterol, triglycerides, and total bilirubin were assessed at baseline, 2 weeks, and 1, 3, 6, 9, and 12 months (HAART group) or 3 month intervals (control group). Serum HIV RNA level (viral load) was determined by reverse-transcriptase polymerase chain reaction (RT-PCR), and serum and peripheral blood mononuclear cell (PBMC) GP73 concentration were determined by chemiluminescent immunoassay kit and western blot, respectively. Significant positive and negative correlations in baseline serum GP73 concentration and HIV viral load (r = 0.39, P < 0.001) and CD4 + T cell count (r = -0.501, P < 0.001) were observed, respectively. In receiver operator characteristic (ROC) analysis, area under the curve (AUC) was 0.79 (95 % CI 0.66-0.92). The sensitivity and specificity of GP73 for correct identification of patients with ≤350 CD4 + T cells/μL were 76.09 and 75.0 %, respectively, with an ROC-derived cut-off of 100.6 ng/mL. For HIV patients undergoing antiretroviral therapy, GP73 may be a potential biomarker treatment efficacy useful in AIDS management.

GP73 is down-regulated in gastric cancer and associated with tumor differentiation

Background

Golgi protein 73 (GP73) is a type II Golgi transmembrane protein. It is over-expressed in several cancers, including hepatocellular carcinomas, bile duct carcinomas, lung cancer and prostate cancer. However, there are few reports of GP73 in gastric cancer. This study is aimed at investigating the expression of GP73 and its relationship with clinical pathological characters in gastric cancer.

Methods

GP73 mRNA level was determined by quantitative real-time RT-PCR in 41 pairs of matched gastric tumorous tissues and adjacent non-tumorous mucosal tissues. Western blotting was also performed to detect the GP73 protein level. GP73 protein expression was analyzed by immunohistochemistry in 52 clinically characterized gastric cancer patients and 10 non-tumorous gastric mucosal tissue controls.

Results

The mRNA and protein level of GP73 were significantly down-regulated in gastric tumorous tissues compared with the non-tumorous mucosal tissues. In non-tumorous mucosa, strong diffuse cytoplasmic staining can be seen in cells located at the surface of the glandular and foveolar compartment; while in tumorous tissues, the staining was much weaker or even absent, and mainly in a semi-granular dot-like staining pattern. The expression level of GP73 protein was associated with patients’ gender and tumor differentiation.

Conclusions

GP73 was normally expressed in non-tumorous gastric mucosa and down-regulated in gastric cancer. Its expression in gastric cancer was correlated with tumor differentiation.

Diagnostic value of immunohistochemical staining of GP73, GPC3, DCP, CD34, CD31, and reticulin staining in hepatocellular carcinoma

It has been reported that Golgi protein-73 (GP73), glypican-3 (GPC3), and des-γ-carboxy prothrombin (DCP) could serve as serum markers for the early detection of hepatocellular carcinoma (HCC). This study aimed to evaluate a panel of immunostaining markers (including GP73, GPC3, DCP, CD34, and CD31) as well as reticulin staining to distinguish HCC from the mimickers. Our results revealed that CD34 immunostaining and reticulin staining were highly sensitive for the diagnosis of HCC. A special immunoreaction pattern of GP73--a diffuse coarse-block pattern in a perinuclear region or a concentrated cluster-like or cord-like pattern in a certain part of the cytoplasm--was observed in HCC cells, in contrast to the cytoplasmic fine-granular pattern in surrounding non-tumor cells and non-malignant nodules. This coarse-block pattern correlated significantly with less differentiated HCC. In comparison, GPC3 displayed a good advantage in diagnosing well-differentiated HCC. In our study, DCP and CD31 showed little diagnostic value for HCC as an immunostaining marker. When GP73, GPC3, and CD34 were combined, the specificity improved to 96.6%. Our findings demonstrate for the first time that the immunohistochemical panel of GP73, GPC3, and CD34 as well as reticulin staining is highly specific for the pathological diagnosis of HCC.