Golgi Phosphoprotein 2 Research Articles

Platelet-Derived Apoptotic Vesicles Promote Bone Regeneration via Golgi Phosphoprotein 2 (GOLPH2)-AKT Signaling Axis.

Apoptotic vesicles (apoVs) are apoptotic-cell-derived nanosized vesicles that take on dominant roles in regulating bone homeostasis. We have demonstrated that mesenchymal stem cell (MSC)-derived apoVs are promising therapeutic agents for bone regeneration. However, clinical translation of MSC-derived apoVs has been hindered due to cell expansion and nuclear substance. As another appealing source for apoV therapy, blood cells could potentially eliminate these limitations. However, whether blood cells can release apoVs during apoptosis is uncertain, and the detailed characteristics and biological properties of respective apoVs are not elucidated. In this study, we showed that platelets (PLTs) could rapidly release abundant apoVs during apoptosis in a short time. To recognize the different protein expressions between PLT-derived apoVs and PLTs, we established their precise protein landscape. Furthermore, we identified six proteins specifically enriched in PLT-derived apoVs, which could be considered as specific biomarkers. More importantly, PLT-derived apoVs promoted osteogenesis of MSCs and rescued bone loss via Golgi phosphoprotein 2 (GOLPH2)-induced AKT phosphorylation, therefore, leading to the emergence of their potential in bone regeneration. In summary, we comprehensively determined characteristics of PLT-derived apoVs and confirmed their roles in bone metabolism through previously unrecognized GOPLH2-dependent AKT signaling, providing more understanding for exploring apoV-based therapy in bone tissue engineering.

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

BACKGROUNDReliable 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.AIMTo assess serum GP73 efficacy as a diagnostic marker of cirrhosis and/or HCC or as predictor of liver disease progression.METHODSGP73 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.RESULTSIncreased 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.CONCLUSIONGP73 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.

Therapeutic Targeting of Golgi Phosphoprotein 2 (GOLPH2) with Armed Antibodies: A Preclinical Study of Anti-GOLPH2 Antibody Drug Conjugates in Lung and Colorectal Cancer Models of Patient Derived Xenografts (PDX).

Golgi phosphoprotein 2 (GOLPH2) has been shown to be involved in chronic inflammatory processes and carcinogenesis. GOLPH2 is prominently overexpressed in hepatocellular carcinoma, melanoma, glioblastoma, prostate, lung, and colorectal cancer. With a low and tightly regulated expression in non-malignant tissues, GOLPH2 has been proposed as an attractive target for cancer therapy. However, GOLPH2 is predominantly located intracellularly and when situated outside of the cell it is proteolytically cleaved and shed from the cell surface. Until now, GOLPH2 has been regarded as an "undruggable" target. We sought to create antibodies that specifically bind to GOLPH2 overexpressing tumor cells. Antibodies binding to membranous GOLPH2 despite shedding of the protein were generated from a scFV library screening. These antibodies target the part of GOLPH2 that remains at the cell surface after proteolytic cleavage. These antibodies were then tested in vitro and in vivo. Two candidates (G2-1 and G2-2) showed target specific binding in vitro. Utilizing a tumor array (n = 128 tumors) with G2-2 and a reference antibody, a GOLPH2 expression scoring system was established. Rapid internalization of the antibodies was noted so this was exploited to deliver a toxic payload of pyrrolobenzodiazepine (PBD). In two patient-derived xenograft (PDX)-models, colorectal and lung cancer, the G2-2 antibody drug conjugate (ADC) displayed high efficacy with significant tumor responses (P = 0.001; P = 0.013) and improved survival (P = 0.0001; P = 0.0011) compared with controls. Treatment with GOLPH2-directed antibodies induces durable responses in colorectal and lung cancer models. With a robust companion assay for GOLPH2 positivity at hand our findings prepare for the translation into a clinical trial.

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

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. 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. 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. 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.

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.

Expression of GOLPH2 is associated with the progression of and poor prognosis in gastric cancer.

Golgi phosphoprotein 2 (GOLPH2) has been associated with the development and progression of various human cancers. The aims of this study were to investigate the relationship between GOLPH2 and gastric cancer (GC) progression and explore the clinical significance of GOLPH2 in GC. GOLPH2 expression was examined in fourpairs of primary GC tissues and the adjacent non-cancerous tissues from the same patients, using immunohistochemistry (IHC), quantitative PCR and western blotting. Furthermore, GOLPH2 protein expression was analyzed in 10normal gastric tissues and 385clinicopathologically characterized cases of GC by IHC. Statistical analyses were performed to determine the prognostic and diagnostic associations. GOLPH2 mRNA and protein expression were both markedly upregulated in GC tissues, compared with the paired adjacent non-cancerous tissues. The Chi-square test and Spearman analysis revealed a significant correlation between GOLPH2 expression and clinical stage, Tclassification, lymph node metastasis, metastasis and venous invasion. Patients with a higher GOLPH2 expression had a shorter overall survival (OS), compared to patients with lower GOLPH2 expression. Notably, our results suggested that GOLPH2 is associated with the development and progression of GC. Therefore, additional studies focusing on the potential of GOLPH2 as a novel therapeutic target in GC are required.

Golgi Phosphoprotein 2 Down-regulates the Th1 Response in Human Gastric Cancer Cells by Suppressing IL-12A

Golgi phosphoprotein 2 (GOLPH2) is a very important biomarker in a variety of diseases. Its biological function is not clear, particularly in gastric cancer. To investigate the role of GOLPH2 in human gastric cancer, and determine its effect on the Th1 lymphocyte response, its expression and that of IL-12A were measured by real-time PCR and immunohistochemistry. The relationship between GOLPH2 and IL-12A was analysed statistically. The effect of GOLPH2 on the Th1 lymphocyte response was investigated with an in vitro co-culture system. The results showed that in human gastric cancer, the expression of GOLPH2 was significantly higher and the expression of IL-12A was lower than in normal gastric mucosal tissues, and the expression levels of GOLPH2 and IL-12A were negatively correlated. In addition, obvious down-regulation of the Th1 response was observed when lymphocytes were co-cultured with gastric cancer SGC7901 cells over-expressing GOLPH2. GOLPH2 down-regulated the expression of IL-12A, and inhibited the expression of TNF-α and IFN-γ. The results indicated that GOLPH2 down-regulates the Th1 response via suppression of IL-12A in human gastric cancer, and this might provide a target for the prevention and treatment.

The Golgi Localization of GOLPH2 (GP73/GOLM1) Is Determined by the Transmembrane and Cytoplamic Sequences

Golgi phosphoprotein 2 (GOLPH2) is a resident Golgi type-II membrane protein upregulated in liver disease. Given that GOLPH2 traffics through endosomes and can be secreted into the circulation, it is a promising serum marker for liver diseases. The structure of GOLPH2 and the functions of its different protein domains are not known. In the current study, we investigated the structural determinants for Golgi localization using a panel of GOLPH2 truncation mutants. The Golgi localization of GOLPH2 was not affected by the deletion of the C-terminal part of the protein. A truncated mutant containing the N-terminal portion (the cytoplasmic tail and transmembrane domain (TMD)) localized to the Golgi. Sequential deletion analysis of the N-terminal indicated that the TMD with a positively charged residue in the cytoplasmic N-terminal tail were sufficient to support Golgi localization. We also showed that both endogenous and secreted GOLPH2 exist as a disulfide-bonded dimer, and the coiled-coil domain was sufficient for dimerization. This structural knowledge is important for the understanding the pathogenic role of GOLPH2 in liver diseases, and the development of GOLPH2-based hepatocellular cancer diagnostic methods.

Up-regulated Golgi phosphoprotein 2 (GOLPH2) expression in lung adenocarcinoma tissue

Objectives The aim of the study was to evaluate Golgi Phosphoprotein 2 (GOLPH2) expression in lung cancer. Design and methods GOLPH2 expression was analyzed from 178 lung cancer tumor tissue samples using immunohistochemistry. Levels of 133 lung cancer patients' serum GOLPH2 (sGOLPH2) were also quantitatively compared with 70 healthy individuals by a sandwich enzyme-linked immunosorbent assay (ELISA). Results All adenocarcinoma (ADC) tissue samples (100%) displayed strong staining, 83.6% of which displayed cytoplasmic diffused staining. However, for squamous cell carcinoma samples, only 16.3% displayed strong staining intensity. Statistically, GOLPH2 expression in tissues of ADC was significantly higher than in other types of lung cancer ( P < 0.001). Levels of sGOLPH2 were also detected. The mean value of sGOLPH2 concentration is 69 ng/ml in lung cancer patients and 53 ng/ml in healthy individuals. Conclusions Significantly elevated GOLPH2 expression was observed in ADC tumor tissues. The levels of sGOLPH2 were about 30% higher in lung cancer patients compared with healthy individuals.

Alpha-fetoprotein and serum golgi phosphoprotein 2 are equally discriminative in detecting early hepatocellular carcinomas #

Li et al. have analyzed golgi phosphoprotein 2 (GOLPH2) serum levels in a cohort of patients with liver cirrhosis, healthy controls, and patients with hepatocellular carcinoma (HCC). They found elevated serum levels of GOLPH2 (sGOLPH2) in early HCC cases. From their findings, the authors conclude that sGOLPH2 is a better marker than alpha-fetoprotein (AFP) for detection of early HCC. In our patients, no significant differences between controls, viral hepatitis (HBV/HCV), and HCC (independent of etiology) were found. However, HCC arising in a hepatitis C virus background had significantly higher GOLPH2 serum levels than healthy controls.1 The findings of Li, Wu, and Fan prompted us to conduct an extended analysis of our dataset. No significant difference of sGOLPH between early HCCs (T1/2 [United Network for Organ Sharing–modified Tumor-Node-Metastasis stages 1 and 2]) and late HCCs (T3/4) was seen. Li et al. had comparable levels of sGOLPH2 in healthy individuals and patients with liver cirrhosis. Although we did not compare cirrhosis with early HCCs, we too see a trend (P = 0.097) of rising values when comparing controls (median 5.7 mg/L) to early HCCs (median 15.8 mg/L). With regard to the notion of Li et al. that sGOLPH2 is a superior marker of early HCC, we find AFP (cutoff 10 ng/mL) and sGOLPH2 (cutoff 10 mg/L) to be equally discriminative and recommend the complementary use of both markers to improve the detection and surveillance of HCCs. We agree that larger studies of GOLPH2 should be pursued to define the role of GOLPH2 in serum-based diagnosis and monitoring of HCC. Ideally, this should be embedded in a prospective, randomized controlled trial. Marc-Oliver Riener*, Frank Stenner , Heike Liewen , Claus Hellerbrand , Marcus Bahra§, Glen Kristiansen*, * Department of Pathology, University Hospital Zürich, Zürich, Switzerland, Department of Oncology, University Hospital Zürich, Zürich, Switzerland, Department of Internal Medicine I, University of Regensburg, Regensburg, Germany, § Visceral and Transplantation Surgery, University Hospital Charité, Berlin, Germany.

Serum Golgi Phosphoprotein 2 level: A better marker than alpha-fetoprotein for diagnosing early hepatocellular carcinoma #

We read with interest the article by Riener et al.1 reporting the potential usefulness of Golgi Phosphoprotein 2 (GOLPH2) as a new serum biomarker for diagnosing hepatocellular carcinoma (HCC). We would like to draw attention to similar studies on the use of serum GOLPH2 in the differentiation of HCC patients from controls with no liver disease and patients with cirrhosis. GOLPH2 was originally described as a resident Golgi type II transmembrane protein expressed primarily in epithelial cells of many human tissues.2 In the normal human liver, GOLPH2 expression was found in biliary epithelial cells, but it was barely detectable in hepatocytes. However, expression of GOLPH2 was found to be strongly up-regulated in hepatocytes from patients with viral and nonviral liver diseases.3 A recent study showed that GOLPH2 was detected in human serum, and it was found to be elevated in the serum and tissue in the woodchuck model of HCC in comparison with the nonneoplastic liver.4 Thus, GOLPH2 may be a potential marker for the early detection of HCC. We tested the serum GOLPH2 levels in patients with HCC (50), patients with cirrhosis (50), and controls with no liver disease (50). Our results showed that GOLPH2 was detected in the sera of all patients, but the levels were higher in patients with HCC and cirrhosis in comparison with controls with no liver disease. Median serum GOLPH2 levels were 1.35 relative units (range, 0.52–12.99) in controls with no liver disease, 4.39 relative units (range, 0.52–26.78) in patients with cirrhosis, and 14.37 relative units (range, 1–57) in those with HCC (P < 0.0001 for HCC versus patients with cirrhosis and controls with no liver disease). Median serum alpha-fetoprotein (AFP) levels were 2.46 ng/mL (range, 1.15–7.68) in controls with no liver disease, 6.11 ng/mL (range, 0.28–625) in patients with cirrhosis, and 16.2 ng/mL (range, 0.89–352,000) in HCC patients (P < 0.0001 for HCC patients versus controls with no liver disease and patients with cirrhosis). When patients with cirrhosis were compared to those with early HCC (United Network for Organ Sharing modified tumor-node-metastasis stages 1 and 2), the median serum GOLPH2 levels were significantly higher in those with early HCC: 12.69 relative units (range, 1–49) versus 4.39 relative units (range, 0.52–26.78) in patients with cirrhosis (P < 0.0001). Median serum AFP levels were also significantly higher in patients with early HCC than in those with cirrhosis: 11.23 ng/mL (range, 1.48–137,000) versus 6.11 ng/mL (range, 0.28–625) in patients with cirrhosis (P < 0.001). However, when we evaluated the sensitivity and specificity of GOLPH2 in patients with early HCC versus those with cirrhosis, the results showed that GOLPH2 (sensitivity, 62%; specificity, 88%) was significantly better than AFP (sensitivity, 25%; specificity, 97%; P < 0.0001). In summary, our data highlight three points. First, we have shown that GOLPH2 is a better marker than AFP for diagnosing early HCC, partially concurring with the findings from Riener et al.'s study. Second, the sample size is not large enough, so we could not establish the performance of GOLPH2 according to the etiology of the underlying liver disease. Third, before this marker can be applied clinically, multicenter cohorts of validation are still needed. Xiaohua Li Ph.D.*, Kaichun Wu Ph.D.*, Daiming Fan Ph.D.*, * Xijing Hospital of Digestive Diseases, Xi'an, China.

Golgi phosphoprotein 2 (GOLPH2) expression in liver tumors and its value as a serum marker in hepatocellular carcinomas #

Hepatocellular carcinomas (HCCs) and bile duct carcinomas (BDCs) have a poor prognosis. Therefore, surveillance strategies including sensitive and specific serum markers for early detection are needed. Recently, Golgi Phosphoprotein 2 (GOLPH2) has been proposed as a serum marker for HCC, but GOLPH2 expression data in liver tissues was not available. Using tissue microarrays and immunohistochemistry, we semiquantitatively analyzed GOLPH2 protein expression in patients with HCC (n = 170), benign liver tumors (n = 22), BDC (n = 114) and normal liver tissue (n = 105). A newly designed sandwich enzyme-linked immunoassay (ELISA) was used to analyze GOLPH2 levels in the sera of patients with HCC (n = 62), hepatitis C virus (HCV) (n = 29), BDC (n = 10), and healthy control persons (n = 12). By immunohistochemistry 121/170 (71%) of HCC showed strong GOLPH2 expression, which was significantly associated with a higher tumor grade (P = 0.01). A total of 97/114 (85%) BDCs showed a strong GOLPH2 expression which proved to be an independent prognostic factor for overall survival (P < 0.05). Serum levels of GOLPH2 measured by ELISA were significantly elevated in patients with HCC with underlying HCV infection (median 18 mg/L, P < 0.05) and patients with BDC (median = 14.5 mg/L, P < 0.01) in comparison to healthy controls (median 4 mg/L). GOLPH2 protein is highly expressed in tissues of HCC and BDC. GOLPH2 protein levels are detectable and quantifiable in sera by ELISA. In patients with hepatitis C, serial ELISA measurements in the course of the disease appear to be a promising complementary serum marker in the surveillance of HCC. GOLPH2 should be further evaluated as a serum tumor marker in BDC on a larger scale.

GOLPH2 and MYO6: Putative prostate cancer markers localized to the Golgi apparatus

Malignant transformation is often accompanied by morphological and functional alterations in subcellular organelles. The Golgi apparatus is a subcellular structure primarily involved in modification and sorting of macromolecules for secretion and transport to other cellular destinations. Molecular alterations associated with the Golgi apparatus may take place during prostate carcinogenesis but such alterations have not been documented. To demonstrate that the Golgi apparatus undergoes alterations during prostate carcinogenesis, we examined the expression and localization of two candidate molecules, Golgi phosphoprotein 2 (GOLPH2) and myosin VI (MYO6), both overexpressed in prostate cancer as initially identified by expression microarray analysis. Elevated GOLPH2 expression in prostate cancers was validated through real-time RT-PCR, Western blot, and tissue microarray analysis, and its Golgi localization in surgical prostate cancer tissues confirmed using two-color immunofluorescence. In addition, distinctive juxtanuclear MYO6 staining pattern consistent with Golgi localization was observed in surgical prostate cancer tissues. Two-color immunofluorescence revealed intensive Golgi-specific staining for both GOLPH2 and myosin VI in prostate cancer cells but not in the adjacent normal prostate epithelium. We show that the Golgi apparatus in prostate cancer cells differs from the normal Golgi by elevated levels of two molecules, GOLPH2 and MYO6. These results for the first time demonstrated consistent cancer cell-specific alterations in the molecular composition of the Golgi apparatus. Such alterations can be explored for discovery of novel prostate cancer biomarkers through targeted organellar approaches.