Golgi protein 73 activation of MMP-13 promotes hepatocellular carcinoma cell invasion. Oncotarget. 2015;6:33523-33533. [PMID: 26378022 PMCID: PMC4741783 DOI: 10.18632/oncotarget.5590]

The first structure of human Golm1 coiled coil domain reveals an unexpected tetramer and highlights its structural diversity

Golgi membrane protein 1 (Golm1), a transmembrane protein with diverse subcellular localizations, has garnered significant attention in recent years due to its strong association with the development and progression of liver diseases and numerous cancers. Interestingly, although Golm1 is a membrane protein, the C-terminal of Golm1, which contains a coiled coil domain and a flexible acid region, can also be detected in the plasma of patients with various liver diseases. Notably, the coiled coil domain of serum Golm1 is postulated to play a pivotal role in physiological and pathological functions. However, little is currently known about the structure of this coiled coil domain and the full-length protein, which may limit our understanding of Golm1. Therefore, this study aims to address this gap in knowledge and reports the first crystal structure of the coiled coil domain of Golm1 at a resolution of 2.28 Å. Meanwhile, we have also confirmed that the Golm1 coiled coil domain in solution can form tetramer. Our results reveal that Golm1 can form a novel tetrameric structure that differs from the previous reported dimeric structure Golm1 could assemble, which may provide novel insights into the diversity of physiological functions and pathological roles.

Loss of MTA2-mediated downregulation of PTK7 inhibits hepatocellular carcinoma metastasis progression by modulating the FAK-MMP7 axis

The expression of metastasis tumor-associated protein 2 (MTA2) and protein tyrosine kinase 7 (PTK7) is associated with hepatocellular carcinoma (HCC) progression. However, the functional effect and mechanism through which MTA2 regulates PTK7-mediated HCC progression remains unclear. Here, we found that MTA2 knockdown significantly down-regulated PTK7 expression in HCC cells (SK-Hep-1 and PLC/PRF/5). Data from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases show that the PTK7 expression level was higher in HCC tissues than in normal liver tissues. In HCC patients, the PTK7 expression level clearly correlated with tumor stage and grade, lower overall survival (OS) correlated positively with MTA2 level, and PTK7 expression acted as a downstream factor for MTA2 expression. In addition, matrix metalloproteinase 7 (MMP7) expression was closely regulated by PTK7, and the mRNA and protein expression levels of MTA2 and PTK7 correlated positively with lower OS. MMP7 downregulation by PTK7 knockdown clearly decreased the migration and invasion abilities of HCC cells. In HCC cells, recombinant human MMP7 reversed the PTK7 knockdown-induced suppression of migration and invasion. Furthermore, deactivation of FAK using siFAK or FAK inhibitor (PF-573228, PF) synergistically contributed to PTK7 knockdown-inhibited FAK activity, MMP7 expression, and the migration and invasion abilities of HCC cells. Collectively, our findings show that PTK7 mediates HCC progression by regulating the MTA2-FAK-MMP7 axis and may be a diagnostic value for HCC patients.

An updated patent review of matrix metalloproteinase (MMP) inhibitors (2021-present)

INTRODUCTION

Matrix metalloproteinases (MMPs) are strongly interlinked with the progression and mechanisms of several life-threatening diseases including cancer. Thus, novel MMP inhibitors (MMPIs) as promising drug candidates can be effective in combating these diseases. However, no MMPIs are marketed to date due to poor pharmacokinetics and lower selectivity. Therefore, this review was performed to study the newer MMPIs patented after the COVID-19 period for an updated perspective on MMPIs.

AREAS COVERED

This review highlights patents related to MMPIs, and their therapeutic implications published between January 2021 and August 2023 available in the Google Patents, Patentscope, and Espacenet databases.

EXPERT OPINION

Despite various MMP-related patents disclosed up to 2020, newer patent applications in the post-COVID-19 period decreased a lot. Besides major MMPs, other isoforms (i.e. MMP-3 and MMP-7) have gained attention recently for drug development. This may open up newer dimensions targeting these MMPs for therapeutic advancements. The isoform selectivity and bioavailability are major concerns for effective MMPI development. Thus, adopting theoretical approaches and experimental methodologies can unveil the development of novel MMPIs with improved pharmacokinetic profiles. Nevertheless, the involvement of MMPs in cancer, and the mechanisms of such MMPs in other diseases should be extensively studied for novel MMPI development.

An Overview of Hepatocellular Carcinoma Surveillance Focusing on Non-Cirrhotic NAFLD Patients: A Challenge for Physicians

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease worldwide and it ranges from simple steatosis to hepatocellular carcinoma (HCC). HCC represents the first liver tumor and the third source of cancer death. In the next few years, the prevalence of NAFLD and consequently of HCC is estimated to increase, becoming a major public health problem. The NAFLD-HCC shows several differences compared to other causes of chronic liver disease (CLD), including the higher percentage of patients that develop HCC in the absence of liver cirrhosis. In HCC surveillance, the international guidelines suggest a six months abdominal ultrasound (US), with or without alpha-fetoprotein (AFP) evaluation, in patients with cirrhosis and in a subgroup of patients with chronic hepatitis B infection. However, this screening program reveals several limitations, especially in NAFLD patients. Thus, new biomarkers and scores have been proposed to overcome the limits of HCC surveillance. In this narrative review we aimed to explore the differences in the HCC features between NAFLD and non-NAFLD patients, and those between NAFLD-HCC developed in the cirrhotic and non-cirrhotic liver. Finally, we focused on the limits of tumor surveillance in NAFLD patients, and we explored the new biomarkers for the early diagnosis of HCC.

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.

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 Complex: A Signaling Hub in Cancer

The Golgi Complex is the central hub in the endomembrane system and serves not only as a biosynthetic and processing center but also as a trafficking and sorting station for glycoproteins and lipids. In addition, it is an active signaling hub involved in the regulation of multiple cellular processes, including cell polarity, motility, growth, autophagy, apoptosis, inflammation, DNA repair and stress responses. As such, the dysregulation of the Golgi Complex-centered signaling cascades contributes to the onset of several pathological conditions, including cancer. This review summarizes the current knowledge on the signaling pathways regulated by the Golgi Complex and implicated in promoting cancer hallmarks and tumor progression.

Dance of The Golgi: Understanding Golgi Dynamics in Cancer Metastasis

The Golgi apparatus is at the center of protein processing and trafficking in normal cells. Under pathological conditions, such as in cancer, aberrant Golgi dynamics alter the tumor microenvironment and the immune landscape, which enhances the invasive and metastatic potential of cancer cells. Among these changes in the Golgi in cancer include altered Golgi orientation and morphology that contribute to atypical Golgi function in protein trafficking, post-translational modification, and exocytosis. Golgi-associated gene mutations are ubiquitous across most cancers and are responsible for modifying Golgi function to become pro-metastatic. The pharmacological targeting of the Golgi or its associated genes has been difficult in the clinic; thus, studying the Golgi and its role in cancer is critical to developing novel therapeutic agents that limit cancer progression and metastasis. In this review, we aim to discuss how disrupted Golgi function in cancer cells promotes invasion and metastasis.

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.

Suppression of GOLM1 by EGCG through HGF/HGFR/AKT/GSK-3β/β-catenin/c-Myc signaling pathway inhibits cell migration of MDA-MB-231

Golgi Membrane Protein 1 (GOLM1) has been identified as a prime target for cancer therapy because it overexpresses in many solid tumors, increases tumor growth and metastasis and leads to unfavorable survival. Though various approaches including siRNA interference and antibody targeting have been attempted, GOLM1 has remained an un-targetable molecule because of its mainly intracellular location and the lack of domains that could possibly be interfered with by small molecules. Numerous natural anti-tumoral plant substances have been identified, while their possible function on GOLM1 has never been revealed. This is the first report to study the relationship between GOLM1 downregulation and natural anti-tumoral plant substances and the possible mechanism. Among three tested possible migration-inhibiting natural substances (Epigallocatechin gallate (EGCG), Betulinic acid (BA) and Lupeol), EGCG showed the most potent inhibition effect on GOLM1 expression and MDA-MB-231 cell migration. Knocking down GOLM1 expression further increased the EGCG treatment effect. Molecular docking prediction and following experiments suggested that EGCG may inhibit GOLM1 expression and MDA-MB-231 cells migration through HGF/HGFR/AKT/GSK-3/β-catenin/c-Myc signaling pathway. In all, EGCG is the first identified GOLM1 downregulation natural product. Silencing GOLM1 may be a novel mechanism of potentiated anti-cancer migration effects and cytotoxic effect of EGCG. In addition, this study shed a new way for cancer therapy by combination of GOLM1 silencing and EGCG treatment in the future.

Serum Tumor Markers for Early Diagnosis of Primary Hepatocellular Carcinoma

Primary hepatocellular carcinoma (HCC) is one of the most frequently occurring pernicious tumors in the world. It is typically very insidious in the early stages with no obvious symptoms. Its development and metastasis are very rapid. Upon diagnosis, most patients have already reached a local advanced stage or have established distant metastases. The treatment of HCC is limited, with poor prognosis and short natural survival time. In order to improve the efficiency of early diagnosis, it is particularly significant to choose economic and effective diagnosis methods. Ultrasound, magnetic resonance imaging, and computed tomography are usually used in the clinic, but these methods are extremely limited in the diagnosis of HCC. Tumor markers have become the main effective early clinical diagnosis method. Potential serum tumor markers include alpha fetoprotein heterogeneity, Golgi protein 73, phosphatidylinositol proteoglycan (GPC-3), osteopontin, abnormal prothrombin, and heat shock protein. These tumor markers provide new ideas and methods for the diagnosis of HCC. A combination of multiple markers can make up for the deficiency of single marker detection and provide a new strategy for the prognosis and auxiliary diagnosis of HCC. This review introduces protein tumor markers utilized over the past five years.

Microenvironmental Hypoxia Induces Dynamic Changes in Lung Cancer Synthesis and Secretion of Extracellular Vesicles

Extracellular vesicles (EVs) mediate critical intercellular communication within healthy tissues, but are also exploited by tumour cells to promote angiogenesis, metastasis, and host immunosuppression under hypoxic stress. We hypothesize that hypoxic tumours synthesize hypoxia-sensitive proteins for packing into EVs to modulate their microenvironment for cancer progression. In the current report, we employed a heavy isotope pulse/trace quantitative proteomic approach to study hypoxia sensitive proteins in tumour-derived EVs protein. The results revealed that hypoxia stimulated cells to synthesize EVs proteins involved in enhancing tumour cell proliferation (NRSN2, WISP2, SPRX1, LCK), metastasis (GOLM1, STC1, MGAT5B), stemness (STC1, TMEM59), angiogenesis (ANGPTL4), and suppressing host immunity (CD70). In addition, functional clustering analyses revealed that tumour hypoxia was strongly associated with rapid synthesis and EV loading of lysosome-related hydrolases and membrane-trafficking proteins to enhance EVs secretion. Moreover, lung cancer-derived EVs were also enriched in signalling molecules capable of inducing epithelial-mesenchymal transition in recipient cancer cells to promote their migration and invasion. Together, these data indicate that lung-cancer-derived EVs can act as paracrine/autocrine mediators of tumorigenesis and metastasis in hypoxic microenvironments. Tumour EVs may, therefore, offer novel opportunities for useful biomarkers discovery and therapeutic targeting of different cancer types and at different stages according to microenvironmental conditions.

Clinicopathological significance of miR-27b targeting Golgi protein 73 in patients with hepatocellular carcinoma

Using five bioinformatics analysis software, we identified Golgi protein 73 (GP73) as a putative target of microRNA-27b (miR-27b), which is closely related to various biological processes or diseases such as bone metabolism disease, adipose cell and muscle cell development, pulmonary hypertension, cervical cancer, and breast cancer. However, the clinical significance of miR-27b in hepatocellular carcinoma (HCC) is still unclear. The differential expression of miR-27b in HCC and adjacent normal liver tissues was measured by quantitative reverse transcription PCR. Our results showed that the expression of miR-27b in tumor tissues is lower than that in adjacent nontumor tissues. The expression of miR-27b was significantly lower in HCC tissues with high expression of GP73, when compared with adjacent nontumor tissues. Moreover, down-regulated expression of miR-27b was closely correlated with serum GP73, tumor-node-metastasis stage, tumor size, and portal vein thrombosis. GP73 mRNA might be a target of miR-27b. The 5-year overall survival rate of the low miR-27b expression group was significantly lower than that of the high miR-27b expression group. Moreover, multivariate analysis of prognostic factors, with a Cox proportional hazards model, showed that low miR-27b expression was a significant and independent predictor of poor survival in HCC. Hence, the abnormal expression of miR-27b might be related to the occurrence and development of tumors. Similarly, a study in the Cancer Genome Atlas database demonstrated that the expression of miR-27b in 50 normal individuals was 1.6 times higher than that of 372 patients with liver cancer. The overall survival rate of the low GP73 expression group (275 liver cancer patients) was significantly longer than that of the high GP73 expression group (90 normal individuals). MiR-27b suppresses the expression of GP73 and is therefore a potential prognostic biomarker and therapy target in HCC.

Golgi protein-73: A biomarker for assessing cirrhosis and prognosis of liver disease patients

BACKGROUND

Reliable biomarkers of cirrhosis, hepatocellular carcinoma (HCC), or progression of chronic liver diseases are missing. In this context, Golgi protein-73 (GP73) also called Golgi phosphoprotein-2, was originally defined as a resident Golgi type II transmembrane protein expressed in epithelial cells. As a result, GP73 expression was found primarily in biliary epithelial cells, with only slight detection in hepatocytes. However, in patients with acute or chronic liver diseases and especially in HCC, the expression of GP73 is significantly up-regulated in hepatocytes. So far, few studies have assessed GP73 as a diagnostic or prognostic marker of liver fibrosis and disease progression.

AIM

To assess serum GP73 efficacy as a diagnostic marker of cirrhosis and/or HCC or as predictor of liver disease progression.

METHODS

GP73 serum levels were retrospectively determined by a novel GP73 ELISA (QUANTA Lite® GP73, Inova Diagnostics, Inc., Research Use Only) in a large cohort of 632 consecutive patients with chronic viral and non-viral liver diseases collected from two tertiary Academic centers in Larissa, Greece (n = 366) and Debrecen, Hungary (n = 266). Aspartate aminotransferase (AST)/Platelets (PLT) ratio index (APRI) was also calculated at the relevant time points in all patients. Two hundred and three patients had chronic hepatitis B, 183 chronic hepatitis C, 198 alcoholic liver disease, 28 autoimmune cholestatic liver diseases, 15 autoimmune hepatitis, and 5 with other liver-related disorders. The duration of follow-up was 50 (57) mo [median (interquartile range)]. The development of cirrhosis, liver decompensation and/or HCC during follow-up were assessed according to internationally accepted guidelines. In particular, the surveillance for the development of HCC was performed regularly with ultrasound imaging and alpha-fetoprotein (AFP) determination every 6 mo in cirrhotic and every 12 mo in non-cirrhotic patients.

RESULTS

Increased serum levels of GP73 (> 20 units) were detected at initial evaluation in 277 out of 632 patients (43.8%). GP73-seropositivity correlated at baseline with the presence of cirrhosis (96.4% vs 51.5%, P < 0.001), decompensation of cirrhosis (60.3% vs 35.5%, P < 0.001), presence of HCC (18.4% vs 7.9%, P < 0.001) and advanced HCC stage (52.9% vs 14.8%, P = 0.002). GP73 had higher diagnostic accuracy for the presence of cirrhosis compared to APRI score [Area under the curve (AUC) (95%CI): 0.909 (0.885-0.934) vs 0.849 (0.813-0.886), P = 0.003]. Combination of GP73 with APRI improved further the accuracy (AUC: 0.925) compared to GP73 (AUC: 0.909, P = 0.005) or APRI alone (AUC: 0.849, P < 0.001). GP73 levels were significantly higher in HCC patients compared to non-HCC [22.5 (29.2) vs 16 (20.3) units, P < 0.001) and positively associated with BCLC stage [stage 0: 13.9 (10.8); stage A: 17.1 (16.8); stage B: 19.6 (22.3); stage C: 32.2 (30.8); stage D: 45.3 (86.6) units, P < 0.001] and tumor dimensions [very early: 13.9 (10.8); intermediate: 19.6 (18.4); advanced: 29.1 (33.6) units, P = 0.004]. However, the discriminative ability for HCC diagnosis was relatively low [AUC (95%CI): 0.623 (0.570-0.675)]. Kaplan-Meier analysis showed that the detection of GP73 in patients with compensated cirrhosis at baseline, was prognostic of higher rates of decompensation (P = 0.036), HCC development (P = 0.08), and liver-related deaths (P < 0.001) during follow-up.

CONCLUSION

GP73 alone appears efficient for detecting cirrhosis and superior to APRI determination. In combination with APRI, its diagnostic performance can be further improved. Most importantly, the simple GP73 measurement proved promising for predicting a worse outcome of patients with both viral and non-viral chronic liver diseases.

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.

Matrix Metalloproteinases as Potential Biomarkers and Therapeutic Targets in Liver Diseases

Chronic liver diseases, characterized by an excessive accumulation of extracellular matrix (ECM) resulting in scar tissue formation, are a growing health problem causing increasing morbidity and mortality worldwide. Currently, therapeutic options for tissue fibrosis are severely limited, and organ transplantation is the only treatment for the end-stage liver diseases. During liver damage, injured hepatocytes release proinflammatory factors resulting in the recruitment and activation of immune cells that activate quiescent hepatic stellate cells (HSCs). Upon activation, HSCs transdifferentiate into highly proliferative, migratory, contractile and ECM-producing myofibroblasts. The disrupted balance between ECM deposition and degradation leads to the formation of scar tissue referred to as fibrosis. This balance can be restored either by reducing ECM deposition (by inhibition of HSCs activation and proliferation) or enhancing ECM degradation (by increased expression of matrix metalloproteinases (MMPs)). MMPs play an important role in ECM remodeling and represent an interesting target for therapeutic drug discovery. In this review, we present the current knowledge about ECM remodeling and role of the different MMPs in liver diseases. MMP expression patterns in different stages of liver diseases have also been reviewed to determine their role as biomarkers. Finally, we highlight MMPs as promising therapeutic targets for the resolution of liver diseases.

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.

mTOR/miR-145-regulated exosomal GOLM1 promotes hepatocellular carcinoma through augmented GSK-3β/MMPs

Golgi membrane protein 1 (GOLM1/GP73) is a serum marker of hepatocellular carcinoma (HCC). We have previously shown that mTOR promoted tumorigenesis of HCC through stimulating GOLM1 expression. In this study, we demonstrated that the mammalian target of rapamycin (mTOR) was a negative regulator of microRNA-145 (miR-145) expression. miR-145 inhibited GOLM1 expression by targeting a coding sequence of GOLM1 gene. GOLM1 and miR-145 were inversely correlated in human HCC tissues. GOLM1-enriched exosomes activated the glycogen synthase kinase-3β/matrix metalloproteinases (GSK-3β/MMPs) signaling axis of recipient cells and accelerated cell proliferation and migration. In contrast, miR-145 suppressed tumorigenesis and metastasis. We suggest that mTOR/miR-145/GOLM1 signaling pathway should be targeted for HCC treatment.

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.

Role of microRNA-141-3p in the progression and metastasis of hepatocellular carcinoma cell

Hepatocellular carcinoma (HCC) is a leading cause of cancer related death worldwide. However, the mechanisms underlying HCC progression and metastasis are still in obscure. Here, we used bioinformatic analysis to identify miRNAs that regulate GP73, a specific marker for HCC diagnosis and prognosis. The correlations between miR-141-3p and clinic-pathological factors were analyzed in HCC patient samples; proliferation, migration, invasion, and colony formation were studied using established HCC cell lines. Expression levels of target genes (miR-141-3p, GP73, E-cadherin, N-cadherin, occludin, vimentin, and cytokeratin 18) were detected by either Western blot or qRT-PCR analysis. Xenograft models were established to evaluate tumor growth and metastasis. MiR-141-3p was significantly reduced in HCC tumors and cell lines, highly correlated with tumor progression. In contrast, GP73 was negatively correlated with miR-141-3p in HCC tumors. MiR-141-3p overexpression significantly decreased HCC cell proliferation, migration, and invasion by inhibiting epithelial-mesenchymal transition (EMT). GP73 overexpression partially restored the inhibitory effects of miR-141-3p, while miR-141-3p overexpression markedly inhibited tumor growth and pulmonary metastasis, which were partially reversed by GP73 overexpression. Our findings suggest that miR-141-3p targets GP73 to reverse EMT, subsequently inhibiting HCC progression and metastasis. Thus, overexpression of miR-141-3p could serve as a therapeutic strategy to arrest HCC.

A Nonsynonymous Variant in the GOLM1 Gene in Cutaneous Malignant Melanoma

Background

Statistically significant linkage of melanoma to chromosome 9q21 was previously reported in a Danish pedigree resource and independently confirmed in Utah high-risk pedigrees, indicating strong evidence that this region contains a melanoma predisposition gene.

Methods

Whole-exome sequencing of pairs of related melanoma case subjects from two pedigrees with evidence of 9q21 linkage was performed to identify the responsible predisposition gene. Candidate variants were tested for association with melanoma in an independent set of 454 unrelated familial melanoma case subjects and 396 unrelated cancer-free control subjects from Utah, and 1534 melanoma case subjects and 1146 noncancer control subjects from Texas (MD Anderson) via a two-sided Fisher exact test.

Results

A rare nonsynonymous variant in Golgi Membrane Protein 1 (GOLM1), rs149739829, shared in two hypothesized predisposition carriers in one linked pedigree was observed. Segregation of this variant in additional affected relatives of the index carriers was confirmed. A statistically significant excess of carriers of the variant was observed among Utah case subjects and control subjects (odds ratio [OR] = 9.81, 95% confidence interval [CI] = 8.35 to 11.26, P < .001) and statistically significantly confirmed in Texas case subjects and control subjects (OR = 2.45, 95% CI = 1.65 to 3.25, P = .02).

Conclusion

These findings support GOLM1 as a candidate melanoma predisposition gene.

Regulatory mechanisms of miR-145 expression and the importance of its function in cancer metastasis

MicroRNAs are post-transcriptional mediators of gene expression and regulation, which play influential roles in tumorigenesis and cancer metastasis. The expression of tumor suppressor miR-145 is reduced in various cancer cell lines, containing both solid tumors and blood malignancies. However, the responsible mechanisms of its down-regulation are a complicated network. miR-145 is potentially able to inhbit tumor cell metastasis by targeting of multiple oncogenes, including MUC1, FSCN1, Vimentin, Cadherin, Fibronectin, Metadherin, GOLM1, ARF6, SMAD3, MMP11, Snail1, ZEB1/2, HIF-1α and Rock-1. This distinctive role of miR-145 in the regulation of metastasis-related gene expression may introduce miR-145 as an ideal candidate for controlling of cancer metastasis by miRNA replacement therapy. The present review aims to discuss the current understanding of the different aspects of molecular mechanisms of miR-145 regulation as well as its role in r metastasis regulation.

Novel biomarkers in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths and the fifth most common cancer worldwide. Most of these patients are seen with advanced disease at the time of presentation. In spite of its high prevalence, there are not many therapeutic options available for patients with advanced-stage HCC. There is an urgent need for improving early detection and prognostication of patients with HCC. In addition, the development of new therapies targeting specific pathways involved in the pathogenesis of HCC should be a major goal for future research, with the objective of improving outcomes of patients with HCC. Biomarkers represent a relatively easy and noninvasive way to detect and estimate disease prognosis. In spite of the numerous efforts to find molecules as possible biomarkers, there is not a single ideal marker in HCC. Many new findings have shown promising results both in diagnosing and treating HCC. In this review, we summarized the most recent and relevant biomarkers in HCC.

Research progress on GP73 in malignant tumors

Malignant cancer is one of the most serious diseases that currently endanger human health. As most tumors are diagnosed at an advanced stage, the current treatments show poor therapeutic efficacy, and the patients have poor prognosis. However, a 5-year survival rate higher than 80% could be achieved if tumors are diagnosed at an early stage. Therefore, early diagnosis and treatment play important roles in the prevention and treatment of malignant tumors, and serum tumor markers are important for the early diagnosis of malignant cancers. Recent studies have shown that GP73, a transmembrane protein, has greater diagnostic value in primary liver cancer than in other types of cancers, and research on the regulation of GP73 expression has unveiled broad prospects in anticancer targeted therapy. Thus, GP73, as a new tumor marker, deserves further study.

TMEM165, a Golgi transmembrane protein, is a novel marker for hepatocellular carcinoma and its depletion impairs invasion activity

Transmembrane protein 165 (TMEM165), a Golgi protein, functions in ion homeostasis and vesicular trafficking in the Golgi apparatus. While mutations in TMEM165 are known to cause human 'congenital disorders of glycosylation', a recessive autosomal metabolic disease, the potential association of this protein with human cancer development has not been explored to date. In the present study, we revealed that TMEM165 is overexpressed in HCC and its depletion weakens the invasive activity of cancer cells through suppression of matrix metalloproteinase‑2 (MMP‑2) expression. Levels of TMEM165 mRNA and protein were clearly increased in HCC patient tissues and cell cultures. Quantitative real‑time RT‑PCR analysis of fresh HCC tissues (n=88) revealed association of TMEM165 overexpression with more frequent macroscopic vascular invasion, microscopic serosal invasion and higher α‑fetoprotein levels. Notably, depletion of TMEM165 led to a marked decrease in the invasive activity of two different HCC cell types, Huh7 and SNU475, accompanied by downregulation of MMP‑2. Our collective findings clearly indicated that TMEM165 contributed to the progression of HCC by promoting invasive activity, supporting its utility as a novel biomarker and therapeutic target for cancer.

Overexpression of Golgi Phosphoprotein 2 Is Associated With Poor Prognosis in Oral Squamous Cell Carcinoma

OBJECTIVES

The aims of this study were to investigate the relationship between Golgi phosphoprotein 2 (GOLPH2) and oral squamous cell carcinoma (OSCC) and explore the clinical significance of GOLPH2 in OSCC.

METHODS

Tissue microarrays from human OSCC samples were stained for GOLPH2 expression and clinicopathologic features. Kaplan-Meier analysis was used to compare the survival of patients with high GOLPH2 expression and patients with low GOLPH2 expression.

RESULTS

We found GOLPH2 is highly expressed in OSCC tissue, and the GOLPH2 expression in metastatic lymph nodes is higher than in tumor tissue. Our data indicate that patients with higher GOLPH2 expression have poor overall survival compared with those with lower GOLPH2 expression. This study demonstrated that GOLPH2 was associated with CD44, SOX2, Slug, B7-H3, B7-H4, TIM3, and VISTA.

CONCLUSIONS

These findings suggest GOLPH2 is a potential marker for estimating the patient's prognosis and may be a target for molecular-targeted therapy against OSCC.

The Emerging Role of Circular RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) ranks the third leading cause of cancer death in the world and has a notably low survival rate. Circular RNAs (circRNAs) are newly classed non-coding RNA (ncRNA) members that are capable of regulating gene expression at transcription or post-transcription levels. Recent studies demonstrate that some circRNAs are differentially expressed in HCC, and the deregulation of these circRNAs is associated with the clinical pathological and prognostic significance. They also play essential roles in HCC progression, and contribute to cell proliferation, migration, invasion and metastasis by targeting different microRNAs (miRNAs) and protein-coding genes. In this review, we concentrate on recent progress of some important circRNAs in HCC, with an emphasis on their deregulation, functions and regulatory mechanisms, and discuss their potential utility as diagnostic and/or prognostic biomarkers or therapeutic targets for HCC.

GP73 N-glycosylation at Asn144 reduces hepatocellular carcinoma cell motility and invasiveness

Golgi Protein 73 (GP73) is a potential liver disease glycobiomarker warranting comprehensive analyses of its glycan structure and glycosylation function. In this study, we used mass spectrometry to identify glycosylation sites and the glycan structure, high-throughput lectin microarray to provide rapid and sensitive profiling of glycoconjugates, and site-directed mutagenesis to clarify the impact of glycans on target glycoproteins in vivo. We identified three GP73 N-glycosylation sites: Asn109, Asn144 and Asn398. We found five glycoforms on Asn144, including biantennary, triantennary and fucosylated glycans. Removal of N-glycans at Asn144 enhanced the motility and invasiveness of hepatocellular carcinoma cells, possibly due to inhibition of cell adhesion related to the changes of cell membrane glycosylation. This study increases our understanding of the functional relevance of GP73 glycosylation and suggests that Asn144-deleted GP73 can influence the progression and metastasis of hepatocellular carcinoma.

GOLM1 promotes prostate cancer progression through activating PI3K-AKT-mTOR signaling

BACKGROUND

Prostate cancer (PCa) is the most commonly diagnosed cancer in men. Various molecular mechanisms account for PCa progression and elucidation of these mechanisms is key for selection of optimal therapies and improvement of patient outcome. Golgi membrane protein 1 (GOLM1) has been identified as a novel biomarker for PCa, but its biological functions and molecular mechanisms remain poorly understood.

METHOD

GOLM1 expression was determined in PCa by tissue microarrays (TMAs) and real-time RT-PCR, Western blot, and immunohistochemistry (IHC) analyses. To investigate GOLM1 functions in vitro and in vivo, we overexpressed and knocked down GOLM1 in PCa cell lines and established xenograft mice models. A series of cytological function assays were used to determine the role of GOLM1 in cell proliferation, migration, invasion, and apoptosis. PI3K-AKT-mTOR signaling pathway downstream of GOLM1 was detected by Western blot and IHC analyses.

RESULT

GOLM1 expression is up-regulated in PCa of all stages and grades. GOLM1 promotes proliferation, migration and invasion, and inhibits apoptosis in PCa cell lines (DU145, PC3, and CWR22Rv1) and xenograft mice models. Moreover, PI3K-AKT-mTOR signaling is positively regulated by GOLM1, whereas PI3 K inhibitor BKM120 significantly abrogates the oncogenic functions of GOLM1.

CONCLUSION

GOLM1 acts as a critical oncogene by promoting PCa cell proliferation, migration and invasion, and inhibiting apoptosis. GOLM1 plays oncogenic functions mainly through activating PI3K-AKT-mTOR signaling pathway. Therefore, agents that block PI3K-AKT-mTOR signaling pathway could be used in PCa patients with GOLM1 up-regulation.

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.

Association of GOLPH2 expression with survival in non-small-cell lung cancer: clinical implications and biological validation

AIM

We investigated the role of GOLPH2 in non-small-cell lung cancer (NSCLC).

METHODS

We analyzed the relationship between the expression of GOLPH2 and the clinical pathological characteristics of patients with NSCLC. The function of GOLPH2 in NSCLC cell lines was also explored through overexpression and knockdown studies.

RESULTS

The positive expression rate of GOLPH2 protein in NSCLC tissue was higher than that of normal lung tissue. We found that positive GOLPH2 expression was closely associated with unfavorable features of patients with NSCLC. The GOLPH2 expression was an independent predictor of the prognosis of patients with NSCLC. That GOLPH2 can promote the proliferation and invasion of NSCLC cells.

CONCLUSION

The GOLPH2 is a novel marker for NSCLC.

MicroRNA-27a/b mediates endothelin-1-induced PPARγ reduction and proliferation of pulmonary artery smooth muscle cells

The down-regulation of peroxisome proliferator-activated receptor γ (PPARγ) expression has been found to correlate with the proliferation of pulmonary artery smooth muscle cells (PASMC), pulmonary vascular remodeling and pulmonary hypertension, while the molecular mechanisms underlying PPARγ reduction in PASMC remain largely unclear. The aim of the current study is to address this issue. Endothelin-1 (ET-1) dose- and time-dependently resulted in PPARγ reduction and proliferation of primary cultured rat PASMC, which was accompanied by the activation of nuclear factor-kappaB (NF-κB) and subsequent induction of microRNA-27a/b (miR-27a/b) expression. Chromatin immunoprecipitation assay revealed that NF-κB directly bound to the promoter regions of miR-27a/b. Luciferase reporter assay identified that miR-27a/b directly regulates the expression of PPARγ in PASMC. Further study indicated that the presence of either NF-κB inhibitor pyrrolidinedithiocarbamate or prior silencing miR-27a/b with anti-miRNA oligonucleotides suppressed ET-1-induced PPARγ reduction and proliferation of PASMC, while overexpression of miR-27a/b reduced PPARγ expression and enhanced PASMC proliferation. Taken together, our study demonstrates that ET-1 stimulates miR-27a/b expression by activation of the NF-κB pathway, which in turn results in PPARγ reduction and contributes to ET-1-induced PASMC proliferation.

Atmospheric particulate matter2.5 promotes the migration and invasion of hepatocellular carcinoma cells

Epidemiological data has demonstrated that particulate matter (PM) with an aerodynamic diameter ≤ 2.5 µm (PM_2.5) is associated with cancer incidence. However, the precise mechanisms underlying PM_2.5-mediated hepatocellular carcinoma cancer (HCC) migration and invasion remain unclear. The aim of the present study was to explore the response of the HCC cell lines HepG2 and HuH-7 to PM_2.5 exposure. The results revealed that PM_2.5 treatment promoted the migration and invasion of HCC cells, in addition to increasing protein levels of matrix metalloproteinase (MMP)-13. Additionally, PM_2.5 induced intracellular reactive oxygen species formation in HCC cells. Further investigation revealed that phosphorylation of RAC-alpha serine/threonine-protein kinase (AKT) increased in response to PM_2.5 exposure in HCC cells, and the AKT antagonist LY294002 reduced PM_2.5-induced migration, invasion and MMP-13 expression. In addition, the data from the present study demonstrated that high concentrations of PM_2.5 decreased the proliferation of normal HL7702 hepatocyte cells and promoted apoptosis. These results indicate that the activation of AKT by PM_2.5 results in MMP-13 overexpression, and stimulates HCC cell migration and invasion. In conclusion, the results from the present study demonstrate that PM_2.5 promotes HCC development and elucidate a potential underlying molecular mechanism for this effect.

A sensitive three monoclonal antibodies based automatic latex particle-enhanced turbidimetric immunoassay for Golgi protein 73 detection

Golgi protein 73 (GP73) is a novel and potential marker for diagnosing hepatocellular carcinoma (HCC) that has been found to be abnormally elevated in liver disease. A latex particle-enhanced turbidimetric immunoassay (LTIA) was recently introduced and licensed for application in a variety of automated clinical chemistry analyzers. However, no studies have reported sufficient data on analytical performance of this method when using 3 monoclonal antibodies for GP73 measurement. The experimental conditions were firstly optimized and range of linearity, diagnostic potential, clinical relevance were compared with the LTIA based on polyclonal antibodies and ELISA. Dilution tests for the LTIA using 3 monoclonal antibodies produced a calibration curve from 10 to 350 ng/mL while the polyclonal antibodies produced the curve from 20 to 320 ng/mL. The detection limit was achieved at 1.82 ng/mL concentration. Within-run CV was obtained in the range of 1.5-2.9% and ROC curves indicated sensitivity and specificity of the LTIA based on 3 monoclonal antibodies were 96.7% and 93.3%, respectively, higher than for the polyclonal antibodies (94.6% and 72.4%) and ELISA (70.0% and 83.3%). Therefore, the LTIA assay based on 3 monoclonal antibodies is thus applicable in quantification of GP73 concentration in automated biochemistry analyzers.

Golgi-Related Proteins GOLPH2 (GP73/GOLM1) and GOLPH3 (GOPP1/MIDAS) in Cutaneous Melanoma: Patterns of Expression and Prognostic Significance

GOLPH2 and GOLPH3 are Golgi-related proteins associated with aggressiveness and progression of a number of cancers. Their prognostic significance in melanoma has not yet been analyzed. We performed immunohistochemical analysis for GOLPH2 and GOLPH3 in 20 normal skin, 30 benign nevi and 100 primary melanoma tissue samples and evaluated their expression in three compartments: cancer cells, tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs). High levels of both proteins in melanoma cells were associated with characteristics of aggressive disease, and shorter disease-free survival (DFS) and cancer-specific overall survival (CSOS). On the contrary, increased numbers of GOLPH2-positive and GOLPH3-positive TAMs were observed in thinner, non-ulcerated tumors, with brisk lymphocytic reaction and absent lymphangioinvasion. Distant metastases were not observed among patients with high numbers of GOLPH2-positive TAMs. Increased expression of either protein in TAMs was related to prolonged CSOS and DFS. Similarly, GOLPH3-expressing CAFs were more frequent in thin melanomas with low mitotic rate, without ulceration and lymphangioinvasion. Moreover, increased GOLPH3-positive CAFs correlated with the absence of regional or distant metastases, and with longer CSOS and DFS. GOLPH2 expression was not observed in CAFs. Our results suggest that GOLPH2 and GOLPH3 play a role in melanoma progression and are potential targets for molecular-based therapies.