Mechanisms of GOLPH3 associated with the progression of gastric cancer: a preliminary study

PRDX1 affects acrylamide-induced neural damage through the PTEN/AKT signaling pathway

Peroxiredoxin 1 (PRDX1) is a member of the peroxidase family of antioxidant enzymes. However, the role and mechanism of PRDX1 in acrylamide (ACR)-induced nerve damage have not been reported. We used SD rats and well-differentiated rat pheochromocytoma cells (PC-12 cells) to established in vivo and in vitro models of ACR. Immunohistochemistry, immunofluorescence and RT-qPCR experiments were used to detect the expression of PRDX1 in neurons of rat hippocampal tissue. The ultrastructural changes of neurons and PC-12 cells in rat hippocampal tissue were observed under transmission electron microscope. Western blot detected the protein expression levels of PRDX1, PTEN, AKT and p-AKT. In vivo and in vitro experimental results showed that PRDX1 showed a significant up-regulation trend after ACR exposure (p < 0.05). In vitro experiments showed that after inhibiting PRDX1 expression with PRDX1 siRNA, the survival rate of PC-12 cells significantly increased, and the damage to cell morphology and organelles was markedly improved. Western blot analysis revealed that ACR exposure can cause a significant increase in PTEN protein expression level and p-AKT/AKT protein ratio (p < 0.05). After inhibiting the expression of PRDX1, the protein expression level of PTEN and the protein ratio of p-AKT/AKT were significantly reduced, while the protein levels of SYN1 and BDNF were significantly increased (p < 0.05). This study, for the first time, demonstrates that PRDX1 affects ACR-induced neurotoxicity by regulating the PTEN/AKT signaling pathway. And, provides novel insights into the prevention and treatment of neurotoxicity in populations exposed to ACR.

Golgi apparatus targeted therapy in cancer: Are we there yet?

Membrane trafficking within the Golgi apparatus plays a pivotal role in the intracellular transportation of lipids and proteins. Dysregulation of this process can give rise to various pathological manifestations, including cancer. Exploiting Golgi defects, cancer cells capitalise on aberrant membrane trafficking to facilitate signal transduction, proliferation, invasion, immune modulation, angiogenesis, and metastasis. Despite the identification of several molecular signalling pathways associated with Golgi abnormalities, there remains a lack of approved drugs specifically targeting cancer cells through the manipulation of the Golgi apparatus. In the initial section of this comprehensive review, the focus is directed towards delineating the abnormal Golgi genes and proteins implicated in carcinogenesis. Subsequently, a thorough examination is conducted on the impact of these variations on Golgi function, encompassing aspects such as vesicular trafficking, glycosylation, autophagy, oxidative mechanisms, and pH alterations. Lastly, the review provides a current update on promising Golgi apparatus-targeted inhibitors undergoing preclinical and/or clinical trials, offering insights into their potential as therapeutic interventions. Significantly more effort is required to advance these potential inhibitors to benefit patients in clinical settings.

Golgi Apparatus Target Proteins in Gastroenterological Cancers: A Comprehensive Review of GOLPH3 and GOLGA Proteins

The Golgi apparatus plays a central role in protein sorting, modification and trafficking within cells; its dysregulation has been implicated in various cancers including those affecting the GI tract. This review highlights two Golgi target proteins, namely GOLPH3 and GOLGA proteins, from this apparatus as they relate to gastroenterological cancers. GOLPH3-a highly conserved protein of the trans-Golgi network-has become a key player in cancer biology. Abnormal expression of GOLPH3 has been detected in various gastrointestinal cancers including gastric, colorectal and pancreatic cancers. GOLPH3 promotes tumor cell proliferation, survival, migration and invasion via various mechanisms including activating the PI3K/Akt/mTOR signaling pathway as well as altering Golgi morphology and vesicular trafficking. GOLGA family proteins such as GOLGA1 (golgin-97) and GOLGA7 (golgin-84) have also been implicated in gastroenterological cancers. GOLGA1 plays an essential role in protein trafficking within the Golgi apparatus and has been associated with poor patient survival rates and increased invasiveness; GOLGA7 maintains Golgi structure while having been shown to affect protein glycosylation processes. GOLPH3 and GOLGA proteins play a pivotal role in gastroenterological cancer, helping researchers unlock molecular mechanisms and identify therapeutic targets. Their dysregulation affects various cellular processes including signal transduction, vesicular trafficking and protein glycosylation, all contributing to tumor aggressiveness and progression.

Expression and Clinical Significance of Golgi Phosphoprotein 3 (GOLPH3) in Papillary Thyroid Carcinoma

This study aimed to explore the correlation of Golgi phosphoprotein 3 (GOLPH3) levels in papillary thyroid carcinoma (PTC) and papillary thyroid microcarcinoma (PTMC) with clinicopathologic features. GOLPH3 expression was determined by western blotting in solid tumors and the adjacent normal thyroid tissues. Mammalian target of rapamycin (mTOR) and Ki-67 were examined by immunohistochemical staining. Significantly higher levels of GOLPH3 protein were observed in PTC and PTMC compared with the adjacent normal thyroid tissues ( P <0.001). GOLPH3 level was positively associated with lymph node metastasis and clinical stage in PTC ( P <0.05) and utterly related to the clinical stage in PTMC ( P =0.012). No correlation was observed between GOLPH3 level and other clinicopathologic parameters such as sex, local invasion, tumor number, and tumor size. The expression level of GOLPH3 protein in mTOR-positive PTC was significantly higher than in mTOR-negative PTC ( P =0.002 in PTC, P =0.022 in PTMC) and positively correlated with Ki-67 proliferation index in PTC via Pearson correlation analysis ( r =0.353, P =0.007 in PTC; r =0.583, P <0.001 in PTMC). In conclusion, the relative expression level of GOLPH3 protein was significantly higher in PTC and PTMC than in normal thyroid tissues and increased with cancer severity. It may provide adjunctive information for diagnosing and predicting prognosis in patients with PTC or PTMC.

GOLPH3 modulates expression and alternative splicing of transcription factors associated with endometrial decidualization in human endometrial stromal cells

Endometrial decidualization is a decidual tissue formed by the proliferation and re-differentiation of endometrial stroma stimulated by decidualization inducing factors. It is very important for the proper maintenance of pregnancy. Previous studies speculated that Golgi phosphoprotein 3 (GOLPH3) may have a regulatory role in the process of endometrial decidualization, while the specific molecular mechanisms of GOLPH3 is unclear. In this part, GOLPH3 was silenced in human endometrial stromal cells (hESCs), and the transcriptome data (RNA-seq) by GOLPH3 knockdown (siGOLPH3) was obtained by high-throughput sequencing technology so as to analyze the potential targets of GOLPH3 at expression and alternative splicing levels in hESCs. Through bioinformatics analysis, we found that siGOLPH3 can significantly affect the overall transcriptional level of hESCs. A total of 6,025 differentially expressed genes (DEGs) and 4,131 differentially alternative splicing events (DASEs) were identified. Through functional cluster analysis of these DEGs and genes where differential alternative splicing events are located, it is found that they are enriched in the PI3K/Akt signaling pathway, RNA splicing and processing, transcription factors and other pathways related to endometrial decidualization and important biological processes, indicating the important biological function of GOLPH3. At the same time, we focused on the analysis of the transcription factors regulated by GOLPH3, including gene expression regulation and the regulation of variable splicing. We found that GOLPH3can regulate the expression of transcription factors such as LD1, FOSL2, GATA2, CSDC2 and CREB3L1. At the same time, it affects the variable splicing mode of FOXM1 and TCF3. The function of these transcription factors is directly related to decidualization of endometrium. Therefore, we infer that GOLPH3 may participate in endometrial de membrane by regulating expression and alternative splicing levels of transcription factors. We further identified the role of GOLPH3 in the transcriptional mechanism. At the same time, it also expands the function mode of GOLPH3 protein molecule, and provides a theoretical basis for downstream targeted drug research and development and clinical application.

Linking GOLPH3 and Extracellular Vesicles Content-a Potential New Route in Cancer Physiopathology and a Promising Therapeutic Target is in Sight?

Golgi phosphoprotein 3 (GOLPH3), a highly conserved phosphatidylinositol 4-phosphate effector, is required for maintenance of Golgi architecture, vesicle trafficking, and Golgi glycosylation. GOLPH3 overexpression has been reported in several human solid cancers, including glioblastoma, breast cancer, colorectal cancer, nonsmall cell lung cancer, epithelial ovarian cancer, prostate cancer, gastric cancer, and hepatocellular carcinoma. Although the molecular mechanisms that link GOLPH3 to tumorigenesis require further investigation, it is likely that GOLPH3 may act by controlling the intracellular movement of key oncogenic molecules, between the Golgi compartments and/or between the Golgi and the endoplasmic reticulum. Indeed, numerous evidence indicates that deregulation of intracellular vesicle trafficking contributes to several aspects of cancer phenotypes. However, a direct and clear link between extracellular vesicle movements and GOLPH3 is still missing. In the past years several lines of evidence have implicated GOLPH3 in the regulation of extracellular vesicle content. Specifically, a new role for GOLPH3 has emerged in controlling the internalization of exosomes containing either oncogenic proteins or noncoding RNAs, especially micro-RNA. Although far from being elucidated, growing evidence indicates that GOLPH3 does not increase quantitatively the excretion of exosomes, but rather regulates the exosome content. In particular, recent data support a role for GOLPH3 for loading specific oncogenic molecules into the exosomes, driving both tumor malignancy and metastasis formation. Additionally, the older literature indirectly implicates GOLPH3 in cancerogenesis through its function in controlling hepatitis C virus secretion, which in turn is linked to hepatocellular carcinoma formation. Thus, GOLPH3 might promote tumorigenesis in unexpected ways, involving both direct and indirect routes. If these data are further confirmed, the spectrum of action of GOLPH3 in tumor formation will significantly expand, indicating this protein as a strong candidate for targeted cancer therapy.

MiR-1/GOLPH3/Foxo1 Signaling Pathway Regulates Proliferation of Bladder Cancer

Objective:

To investigate role of microRNA-1/Golgi phosphoprotein 3/Foxo1 axis in bladder cancer.

Methods:

The expression of Golgi phosphoprotein 3 was determined in both bladder cancer tissues and cell lines using quantitative real-time polymerase chain reaction and Western blotting, respectively. Golgi phosphoprotein 3 was knocked down by small hairpin RNA. MicroRNA-1 was overexpressed or inhibited by microRNA-1 mimic or inhibitor. Cell viability and proliferation were determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) and colony-formation assay. Cell apoptosis and cycle was detected using flow cytometer. The expression of microRNA-1 and Golgi phosphoprotein 3 was determined using quantitative real-time polymerase chain reaction and Western blotting was used to test the expression of Golgi phosphoprotein 3, Foxo1, p-Foxo1, AKT, p-AKT, p27, and CyclinD1. Binding between microRNA-1 and Golgi phosphoprotein 3 was confirmed by Dual-Luciferase Reporter Assay.

Results:

MicroRNA-1 was downregulated in bladder cancer tissues, while Golgi phosphoprotein 3 was overexpressed in bladder cancer cells and tissues. In both bladder cancer 5637 and T24 cell lines, the cell viability and proliferation were dramatically reduced when Golgi phosphoprotein 3 was knocked down. The inhibition of Golgi phosphoprotein 3 remarkably promoted cell apoptosis and induced cell-cycle arrest, as well as decreased the expression of p-Foxo1, p-AKT, and CyclinD1 and increased the expression of p27. The overexpression of microRNA-1 significantly inhibited cell viability and proliferation, induced G-S cell-cycle arrest, and decreased the expression of Golgi phosphoprotein 3, p-Foxo1, and CyclinD1 and upregulated p27, while inhibition of microRNA-1 led to opposite results. Golgi phosphoprotein 3 was a direct target for microRNA-1.

Conclusion:

Overexpression of microRNA-1 inhibited cell proliferation and induced cell-cycle arrest of bladder cancer cells through targeting Golgi phosphoprotein 3 and regulation of Foxo1.

Golgi phosphoprotein 3 (GOLPH3) promotes endometrial carcinoma cell invasion and migration by regulating the epithelial-mesenchymal transition

BACKGROUND:

Golgi phosphoprotein 3 (GOLPH3) is a novel oncogene overexpressed in several human cancers, but specific contributions to endometrial carcinoma (EC) have not been examined. The aims of this study were to evaluate the GOLPH3 expression in EC and investigate its functions in EC cell proliferation, migration, and survival.

METHODS:

The expression levels of GOLPH3 in EC patient samples and EC cell lines (HEC-1A, KLE, RL95-2, and Ishikawa) were examined using qRT-PCR, western blotting and immunohistochemistry. Further, EC cell lines with either ectopic GOLPH3 overexpression or knockdown were established, and the effects on proliferation, apoptosis, invasion, and migration were investigated in vitro using cell viability and transwell assays and in mice following cell injection.

RESULTS:

Compared to adjacent non-cancerous tissues, expression of GOLPH3 was significantly upregulated in EC tissues (P< 0.05), and the expression level of GOPLPH3 was related to the grade of the tumor (P< 0.05). The expression of GOLPH3 was also higher in all four EC cell lines than endometrial stromal cells (ESCs) (P< 0.05). Moreover, GOLPH3 expression was greater in EC cell lines with high invasive capacity than in non-invasive EC cells (P< 0.05). Knockdown of GOLPH3 inhibited EC cell proliferation and increased cell apoptosis in vitro. Further, knockdown of GOLPH3 also inhibited EC cell invasion and migration in vitro and in vivo by regulating the epithelial-mesenchymal transition (EMT). Conversely, GOLPH3 overexpression promoted proliferation and migration.

CONCLUSIONS:

The present study provides evidence that GOLPH3 promotes EMT and metastasis of EC cells and predicts the risk of EC progression, highlighting its potential as a therapeutic target for this malignancy.

Oncogenic Roles of GOLPH3 in the Physiopathology of Cancer

Golgi phosphoprotein 3 (GOLPH3), a Phosphatidylinositol 4-Phosphate [PI(4)P] effector at the Golgi, is required for Golgi ribbon structure maintenance, vesicle trafficking and Golgi glycosylation. GOLPH3 has been validated as an oncoprotein through combining integrative genomics with clinopathological and functional analyses. It is frequently amplified in several solid tumor types including melanoma, lung cancer, breast cancer, glioma, and colorectal cancer. Overexpression of GOLPH3 correlates with poor prognosis in multiple tumor types including 52% of breast cancers and 41% to 53% of glioblastoma. Roles of GOLPH3 in tumorigenesis may correlate with several cellular activities including: (i) regulating Golgi-to-plasma membrane trafficking and contributing to malignant secretory phenotypes; (ii) controlling the internalization and recycling of key signaling molecules or increasing the glycosylation of cancer relevant glycoproteins; and (iii) influencing the DNA damage response and maintenance of genomic stability. Here we summarize current knowledge on the oncogenic pathways involving GOLPH3 in human cancer, GOLPH3 influence on tumor metabolism and surrounding stroma, and its possible role in tumor metastasis formation.

Clinicopathologic Features and Prognostic Implications of Golgi Phosphoprotein 3 in Non-small Cell Lung Cancer: A Meta-analysis

Background: A number of studies have investigated the role of Golgi phosphoprotein-3 (GOLPH3) in the pathogenesis and progression of non-small cell lung cancer (NSCLC). However, the results of previous studies are heterogeneous and controversial. The aim of this meta-analysis was to clarify its association with the clinicopathological characteristics of patients and evaluate the prognostic significance of GOLPH3 in NSCLC.

Methods: A systematic search was conducted through PMC, PubMed, Medline, Web of Science, Chinese National Knowledge Infrastructure and Wanfang database. The odds ratio (OR) and hazard ratio (HR) with 95 % CI were calculated by STATA 12.0.

Results: 8 qualified studies with a total of 1001 patients with NSCLC were included. Pooled results showed that GOLPH3 was highly expressed in tumor tissues compared with adjacent lung tissues (OR, 7.55), and overexpression of GOLPH3 was significantly correlated with advanced clinical stage (OR, 3.42), poor differentiation of tumor (OR, 1.97) and positive lymph node metastasis (OR, 2.58), but no association with histological type, gender, age or tumor size was found in NSCLC patients. In addition, the pooled HR for overall survival was 1.79 by univariate analysis and 1.91 by multivariate analysis. The pooled HR for progression-free survival was 2.50.

Conclusions: GOLPH3 could be a risk factor for progression of NSCLC and might act as a potential prognostic biomarker for NSCLC patients.

The Great Escape: how phosphatidylinositol 4-kinases and PI4P promote vesicle exit from the Golgi (and drive cancer)

Phosphatidylinositol 4-phosphate (PI4P) is a membrane glycerophospholipid and a major regulator of the characteristic appearance of the Golgi complex as well as its vesicular trafficking, signalling and metabolic functions. Phosphatidylinositol 4-kinases, and in particular the PI4KIIIβ isoform, act in concert with PI4P to recruit macromolecular complexes to initiate the biogenesis of trafficking vesicles for several Golgi exit routes. Dysregulation of Golgi PI4P metabolism and the PI4P protein interactome features in many cancers and is often associated with tumour progression and a poor prognosis. Increased expression of PI4P-binding proteins, such as GOLPH3 or PITPNC1, induces a malignant secretory phenotype and the release of proteins that can remodel the extracellular matrix, promote angiogenesis and enhance cell motility. Aberrant Golgi PI4P metabolism can also result in the impaired post-translational modification of proteins required for focal adhesion formation and cell–matrix interactions, thereby potentiating the development of aggressive metastatic and invasive tumours. Altered expression of the Golgi-targeted PI 4-kinases, PI4KIIIβ, PI4KIIα and PI4KIIβ, or the PI4P phosphate Sac1, can also modulate oncogenic signalling through effects on TGN-endosomal trafficking. A Golgi trafficking role for a PIP 5-kinase has been recently described, which indicates that PI4P is not the only functionally important phosphoinositide at this subcellular location. This review charts new developments in our understanding of phosphatidylinositol 4-kinase function at the Golgi and how PI4P-dependent trafficking can be deregulated in malignant disease.

GOLPH3: a Golgi phosphatidylinositol(4)phosphate effector that directs vesicle trafficking and drives cancer

GOLPH3 is a peripheral membrane protein localized to the Golgi and its vesicles, but its purpose had been unclear. We found that GOLPH3 binds specifically to the phosphoinositide phosphatidylinositol(4)phosphate [PtdIns(4)P], which functions at the Golgi to promote vesicle exit for trafficking to the plasma membrane. PtdIns(4)P is enriched at the trans-Golgi and so recruits GOLPH3. Here, a GOLPH3 complex is formed when it binds to myosin18A (MYO18A), which binds F-actin. This complex generates a pulling force to extract vesicles from the Golgi; interference with this GOLPH3 complex results in dramatically reduced vesicle trafficking. The GOLPH3 complex has been identified as a driver of cancer in humans, likely through multiple mechanisms that activate secretory trafficking. In this review, we summarize the literature that identifies the nature of the GOLPH3 complex and its role in cancer. We also consider the GOLPH3 complex as a hub with the potential to reveal regulation of the Golgi and suggest the possibility of GOLPH3 complex inhibition as a therapeutic approach in cancer.

Golgi phosphoprotein 3 (GOLPH3) promotes hepatocellular carcinoma progression by activating mTOR signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the second leading cause of cancer-related deaths worldwide. Despite new technologies in diagnosis and treatment, the incidence and mortality of HCC continue rising. And its pathogenesis is still unclear. As a highly conserved protein of the Golgi apparatus, Golgi phosphoprotein 3 (GOLPH3) has been shown to be involved in tumorigenesis of HCC. This study aimed to explore the exact oncogenic mechanism of GOLPH3 and provide a novel diagnose biomarker and therapeutic strategy for patients with HCC.

METHODS

Firstly, the expression of GOLPH3 was detected in the HCC tissue specimens and HCC cell lines. Secondly, RNA interference was used for GOLPH3 gene inhibition. Thirdly, cell proliferation was analyzed by MTT; cell apoptosis was analyzed by Annexin-V/PI staining, Hoechst 33,342 staining and caspase 3/7 activity assay. Fourthly, xenograft tumor model was used to study the function of GOLPH3 in tumor growth in vivo. Finally, western blotting and immunohistochemistry were used to investigate the role of GOLHP3 in the mTOR signaling pathway.

RESULTS

Data showed that the mRNA and protein expression of GOLPH3 were up-regulated in HCC tumor tissue and cell lines compared with those of control (P < 0.05). Correlation analyses showed that GOLPH3 expression was positively correlated with serum alpha-fetoprotein level (AFP, P = 0.006). Knockdown GOLPH3 expression inhibited proliferation and promoted apoptosis in HCC cell lines. What's more, knockdown GOLPH3 expression led to tumor growth restriction in xenograft tumor model. The expression of phosphorylated mTOR, AKT and S6 K1 were significantly higher in HCC tumor tissue and cell lines compared with those in normal liver tissues (p < 0.05). While the phosphorylated mTOR, AKT and S6 K1 were much lower when diminished GOLPH3 expression in HCC cell lines both in vitro and in vivo.

CONCLUSION

The current study suggests that GOLPH3 contributes to the tumorigenesis of HCC by activating mTOR signaling pathway. GOLPH3 is a promising diagnose biomarker and therapeutic target for HCC. Our study may provide a scientific basis for developing effective approaches to treat the HCC patients with GOLPH3 overexpression.

GOLPH3 overexpression correlates with poor response to neoadjuvant therapy and prognosis in locally advanced rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) combined with surgery is a standard therapy for locally advanced rectal cancer (LARC). The aim of this study was to assess the expression of GOLPH3 (Golgi phosphoprotein 3), a newly found oncogene, in LARC as well as its relationship with nCRT sensitivity and prognosis. We retrospectively analyzed 148 LARC cases receiving nCRT and total mesorectal excision (TME). Immunohistochemistry was used to assess GOLPH3 and mTOR (mammalian target of rapamycin) in tumor tissues. Then, the associations of GOLPH3 with pathological characteristics and prognosis of rectal cancer were assessed. The 148 cases included 77 with high GOLPH3 expression (52.03%), which was associated with tumor invasive depth and lymphatic metastasis. Cases with high GOLPH3 expression had 2.58 and 2.71 fold higher local relapse and distant metastasis rates compared with the low expression group. Correlation analyses showed that GOLPH3 was an independent indicator for judging tumor down-staging and postoperative TRG (tumor regression grade), indicating it could predict nCRT sensitivity. In addition, GOLPH3 expression was associated with mTOR levels. Multiple-factor analysis indicated that GOLPH3 was an independent prognosis indicator for 5 year-DFS (disease free survival) and OS (overall survival) in LARC. These results reveal that GOLPH3 is an independent predictive factor for nCRT sensitivity and prognosis in LARC, with a mechanism related to mTOR.

CENPH Inhibits Rapamycin Sensitivity by Regulating GOLPH3-dependent mTOR Signaling Pathway in Colorectal Cancer

Background: Centromere protein H (CENPH) is known as a fundamental component of the active centromere complex, and its overexpression is correlated with poor prognosis in various solid tumors. mTOR inhibitor rapamycin has been shown to possess antitumor activity, as well as prevent intestinal tumorigenesis. However, the prognostic value of CENPH in colorectal cancer (CRC) and the role of CENPH in rapamycin sensitivity remain unknown. Materials and methods: The effect of CENPH on the cell proliferation, clonogenicity, and cell response to rapamycin in CRC were evaluated by MTT and/or colony formation assays. For the underlying mechanisms, the interaction between CENPH and GOLPH3 were detected by co-immunoprecipitation, GST pull-down, and His-tag pull-down assays, as well as the laser scanning confocal microscopy. The status of kinases in mTOR signaling was determined by Western blot. Finally, the clinical significance of CENPH was analyzed using public CRC datasets with CENPH transcripts and clinical information. Results: CENPH inhibited CRC malignant phenotypes, conferred reduced sensitivity to rapamycin, and attenuated both mTORC1 and mTORC2 in mTOR signaling pathway through the interaction with golgi phosphoprotein 3 (GOLPH3), which has been identified as a potential oncogene and modulates the response to rapamycin. Moreover, elevated levels of CENPH were detected in CRC tissues, compared with normal colorectal tissues. High levels of CENPH expression gradually decreased according to CRC tumor stages. Patients with high CENPH expression had favorable survival. Conclusions: Our results suggest that CENPH inhibits rapamycin sensitivity by regulating GOLPH3 dependent mTOR pathway. High CENPH expression is associated with better prognosis in CRC patients. Taken together, CENPH may serve as a potential predictor for rapamycin sensitivity and therapeutic target for CRC patients.

Golgi Phosphoprotein 3 Inhibits the Apoptosis of Human Glioma Cells in Part by Downregulating N-myc Downstream Regulated Gene 1

Background

Golgi phosphoprotein 3 (GOLPH3) has been reported to be involved in the development of several human cancers. Our previous study showed that GOLPH3 expression in glioma tissues was related to the severity of the malignancy of the cancer. However, the mechanism by which GOLPH3 affects cell apoptosis is largely unknown. The present study was designed to explore the possible mechanism of GOLPH3 in cell apoptosis.

Material/Methods

To analyze the biological role of GOLPH3 in glioma cells, we used GOLPH3 small interference RNA in apoptosis of glioma cells. The apoptosis of glioma cells was detected by flow cytometry. The expression level of GOLPH3 and NDRG1 protein was determined by Western blot analyses and immunohistochemical staining, respectively, to evaluate their association with glioma. Tumor tissues were collected from patients with glioma. Normal cerebral tissues were acquired from cerebral trauma patients undergoing internal decompression surgery.

Results

We confirm that the decrease of GOLPH3 that promotes the apoptosis of glioma cells may be regulated by the activation of NDRG1 and cleaved capcase 3. There was a inverse association between GOLPH3 and NDRG1 in glioma samples.

Conclusions

Our findings indicate that GOLPH3 and NDRG1 both play an important role in glioma etiology. Either GOLPH3 or NDRG1 might be a potential candidate for malignant glioma therapy.

Cigarette Smoking Condensate Disrupts Endoplasmic Reticulum-Golgi Network Homeostasis Through GOLPH3 Expression in Normal Lung Epithelial Cells

INTRODUCTION

Cigarette smoke (CS) is associated with a broad range of diseases including lung cancer. Many researchers have suggested that cigarette smoke condensate (CSC) may be more toxic compared to cigarette smoke extract (CSE) because CSC contains the lipid-soluble faction of smoke while CSE contains the hydrophilic or gas phase. The aim of this research is to investigate the effects of CSC on the disruption of endoplasmic reticulum (ER)-Golgi homeostasis in normal lung epithelial cells.

METHODS

CS was generated according to the ISO 3308 method. To ascertain the mechanistic effects of CSC on lung toxicity, normal lung epithelial cells of the cell line 16HBE14o- were treated with CSC (0.1mg/mL) for 48 hours. The toxic effects of CSC on ER-Golgi homeostasis and GOLPH3 expression were observed through diverse molecular tools including transmission electron microscope analysis.

RESULTS

Our results demonstrated that CSC treatment increased reactive oxygen species generation in lung cells and led to the alteration of ER-Golgi homeostasis in conjunction with increased autophagy. In particular, GOLPH3, known as an oncogene and a marker protein for the trans-Golgi network, was upregulated in CSC-treated cells. GOLPH3 protein overexpression was also confirmed in the lungs of human lung cancer patients as well as NNK-treated mice.

CONCLUSION

Our study revealed that CSC caused lung damage through the disruption of ER-Golgi homeostasis and autophagy induction. The expression level of the trans-Golgi marker protein GOLPH3 could serve as a reliable bio-indicator for CS-related lung cancer.

IMPLICATIONS

CS is a harmful factor in the development of many diseases including cancer. In this research, we demonstrated that CSC treatment led to malfunction of the ER-Golgi network, with the disrupted ER and Golgi causing GOLPH3 overexpression and abnormal autophagy accumulation. In addition, although the value of GOLPH3 as a predictor remains to be fully elucidated, our data suggest that GOLPH3 levels may be a novel prognostic biomarker of tobacco related lung disease.

Identification of prostate cancer biomarkers in urinary exosomes

Exosomes have recently appeared as a novel source of non-invasive cancer biomarkers since tumour-specific molecules can be found in exosomes isolated from biological fluids. We have here investigated the proteome of urinary exosomes by using mass spectrometry to identify proteins differentially expressed in prostate cancer patients compared to healthy male controls. In total, 15 control and 16 prostate cancer samples of urinary exosomes were analyzed. Importantly, 246 proteins were differentially expressed in the two groups. The majority of these proteins (221) were up-regulated in exosomes from prostate cancer patients. These proteins were analyzed according to specific criteria to create a focus list that contained 37 proteins. At 100% specificity, 17 of these proteins displayed individual sensitivities above 60%. Even though several of these proteins showed high sensitivity and specificity for prostate cancer as individual biomarkers, combining them in a multi-panel test has the potential for full differentiation of prostate cancer from non-disease controls. The highest sensitivity, 94%, was observed for transmembrane protein 256 (TM256; chromosome 17 open reading frame 61). LAMTOR proteins were also distinctly enriched with very high specificity for patient samples. TM256 and LAMTOR1 could be used to augment the sensitivity to 100%. Other prominent proteins were V-type proton ATPase 16 kDa proteolipid subunit (VATL), adipogenesis regulatory factor (ADIRF), and several Rab-class members and proteasomal proteins. In conclusion, this study clearly shows the potential of using urinary exosomes in the diagnosis and clinical management of prostate cancer.

[Effect of phosphoinositide 4-phosphate on invasion and migration of human glioma U87 cells]

OBJECTIVE

To investigate the effect of phosphoinositide 4-phosphate (PI4P) on human glioma U87 cells and the mechanism of action of PI4P in the development of human glioma through the overexpression or silencing of PI4P in human glioma U87 cells, and to provide a new target for basic research and clinical treatment of glioma.

METHODS

LV-Helper1, LV-Helper2, pWPXLd-PI4P, and pLL3.7-shPI4P were used to package pWPXLd-PI4P and pLL3.7-shPI4P lentiviruses. The U87-GFP (PI4P-overexpression control group), U87-GFP-PI4P (PI4P-overexpression experimental group), U87-Scramble (PI4P-silencing control group), and U87-shPI4P (PI4P-silencing experimental group) cell lines were established. Wound-healing assay and Transwell assay were used to evaluate cell migration and invasion, and Western blot was used to measure the expression of PI4P in each group.

RESULTS

Western blot detected the expression of exogenous PI4P in the U87-GFP-PI4P cell line, and the U87-shPI4P cell line showed reduced expression of PI4P compared with the U87-Scramble cell line in the control group. The U87-GFP-PI4P cell line with PI4P overexpression had a significantly stronger ability of migration than the U87-GFP cell line in the control group (P<0.01); the U87-shPI4P cell line with PI4P silencing had a reduced ability of migration than the U87-Scramble cell line in the control group (P<0.01). The U87 cell line with PI4P overexpression had a significantly stronger invasion ability than the control group (P<0.05); after PI4P silencing, the experimental group showed a significant reduction in invasion ability compared with the control group (P<0.05).

CONCLUSIONS

In human glioma U87 cells, PI4P can promote the invasion and migration of glioma cells and may become a new target in the basic research and clinical treatment of glioma.

Correlation of GOLPH3 Gene with Wnt Signaling Pathway in Human Colon Cancer Cells

Objective: Overexpression of GOLPH3 in colorectal cancer tissue may promote cell proliferation and activate the Wnt signaling pathway. We investigated the correlation between GOLPH3 gene expression and the Wnt signaling pathway to explore the mechanism of the overexpression of GOLPH3 gene which promotes proliferation in human colon cancer cells.

Methods: We measured expression of GOLPH3 mRNA in the human colon cancer cell lines HCT116, HT29, SW480 and SW620 by RT-PCR, and the cells with the highest expression were selected and divided into four groups: negative control, GOLPH3 siRNA transfection (siRNA-GOLPH3), Akt inhibitor (Tricinbine), and glycogen synthase kinase (GSK)-3β inhibitor (TWS119). After human colon cancer cells were transfected with siRNA-GOLPH3, we used RT-PCR to investigate the silencing effect of GOLPH3 gene. We assessed the activity of the Wnt signaling pathway in all groups using the Topflash method. Proliferation and apoptosis of colon cancer SW620 cells were detected by MTT assay, colony formation assay and flow cytometry. Expression of Golgi phosphoprotein (GOLPH)3, β-catenin, GSK-3β and pS9-GSK-3β in cancer cells was determined by Western blotting.

Results: SW620 cells expressed the highest level of GOLPH3 mRNA, and the silence effect was good after they were transfected with siRNA-GOLPH3. The relative luminescence units (RLU) values in the experimental groups were significantly lower than in the negative control group (P<0.001). There was no significant difference in the RLU values among the experimental groups (P> 0.05). The growth inhibition ratio and apoptosis rate of cancer cells in each experimental group were significantly higher than those in the control group, and the cell colony count in the experimental group was significantly lower than in the control group (P<0.05). In addition, the RLU value, proliferation and apoptosis rate of cancer cells did not differ significantly between each two experimental groups. Western blotting showed that, compared with the control group, expression of β-catenin and pS9-GSK3 proteins were significantly decreased in the experimental group. Expression of GSK-3β in the experimental group did not different from that of the control group.

Conclusions: Overexpression of GOLPH3 gene activated the Wnt signaling pathway, as well as increasing expression of β-catenin, promoting proliferation and inhibiting apoptosis in human colon cancer cells. The mechanism of action was that overexpression of GOLPH3 gene activated Akt, which may also further activate the Wnt signaling pathway via GSK-3β, and promote proliferation in human colon cancer cells.

Distinct Biochemical Pools of Golgi Phosphoprotein 3 in the Human Breast Cancer Cell Lines MCF7 and MDA-MB-231

Golgi phosphoprotein 3 (GOLPH3) has been implicated in the development of carcinomas in many human tissues, and is currently considered a bona fide oncoprotein. Importantly, several tumor types show overexpression of GOLPH3, which is associated with tumor progress and poor prognosis. However, the underlying molecular mechanisms that connect GOLPH3 function with tumorigenicity are poorly understood. Experimental evidence shows that depletion of GOLPH3 abolishes transformation and proliferation of tumor cells in GOLPH3-overexpressing cell lines. Conversely, GOLPH3 overexpression drives transformation of primary cell lines and enhances mouse xenograft tumor growth in vivo. This evidence suggests that overexpression of GOLPH3 could result in distinct features of GOLPH3 in tumor cells compared to that of non-tumorigenic cells. GOLPH3 is a peripheral membrane protein mostly localized at the trans-Golgi network, and its association with Golgi membranes depends on binding to phosphatidylinositol-4-phosphate. GOLPH3 is also contained in a large cytosolic pool that rapidly exchanges with Golgi-associated pools. GOLPH3 has also been observed associated with vesicles and tubules arising from the Golgi, as well as other cellular compartments, and hence it has been implicated in several membrane trafficking events. Whether these and other features are typical to all different types of cells is unknown. Moreover, it remains undetermined how GOLPH3 acts as an oncoprotein at the Golgi. Therefore, to better understand the roles of GOLPH3 in cancer cells, we sought to compare some of its biochemical and cellular properties in the human breast cancer cell lines MCF7 and MDA-MB-231 with that of the non-tumorigenic breast human cell line MCF 10A. We found unexpected differences that support the notion that in different cancer cells, overexpression of GOLPH3 functions in diverse fashions, which may influence specific tumorigenic phenotypes.

A Genome Wide Study of Copy Number Variation Associated with Nasopharyngeal Carcinoma in Malaysian Chinese Identifies CNVs at 11q14.3 and 6p21.3 as Candidate Loci

Background

Nasopharyngeal carcinoma (NPC) is a neoplasm of the epithelial lining of the nasopharynx. Despite various reports linking genomic variants to NPC predisposition, very few reports were done on copy number variations (CNV). CNV is an inherent structural variation that has been found to be involved in cancer predisposition.

Methods

A discovery cohort of Malaysian Chinese descent (NPC patients, n = 140; Healthy controls, n = 256) were genotyped using Illumina^® HumanOmniExpress BeadChip. PennCNV and cnvPartition calling algorithms were applied for CNV calling. Taqman CNV assays and digital PCR were used to validate CNV calls and replicate candidate copy number variant region (CNVR) associations in a follow-up Malaysian Chinese (NPC cases, n = 465; and Healthy controls, n = 677) and Malay cohort (NPC cases, n = 114; Healthy controls, n = 124).

Results

Six putative CNVRs overlapping GRM5, MICA/HCP5/HCG26, LILRB3/LILRA6, DPY19L2, RNase3/RNase2 and GOLPH3 genes were jointly identified by PennCNV and cnvPartition. CNVs overlapping GRM5 and MICA/HCP5/HCG26 were subjected to further validation by Taqman CNV assays and digital PCR. Combined analysis in Malaysian Chinese cohort revealed a strong association at CNVR on chromosome 11q14.3 (P_combined = 1.54x10^-5; odds ratio (OR) = 7.27; 95% CI = 2.96–17.88) overlapping GRM5 and a suggestive association at CNVR on chromosome 6p21.3 (P_combined = 1.29x10^-3; OR = 4.21; 95% CI = 1.75–10.11) overlapping MICA/HCP5/HCG26 genes.

Conclusion

Our results demonstrated the association of CNVs towards NPC susceptibility, implicating a possible role of CNVs in NPC development.

Golgi phosphoprotein 3 regulates metastasis of prostate cancer via matrix metalloproteinase 9

Recent studies suggest that Golgi phosphoprotein 3 (GOLPH3) protein is a candidate metastasis gene in human cancer. The goal of this study was to determine the function of GOLPH3 in prostate cancer metastasis and to identify GOLPH3-regulated pathways and genes involved in prostate cancer metastasis. GOLPH3 expression was detected in prostate cancer. To investigate its function, PC-3 cells were stably transfected with shRNA targeting GOLPH3. Cell abilities of invasion and migration were measured in vitro. Downstream regulatory pathways of GOLPH3 were characterized using quantitative RT-PCR and Western blotting analysis. Immunohistochemical studies in prostate cancer specimens revealed a positive correlation of GOLPH3 expression with prostate cancer. GOLPH3 was expressed in prostate cancer cell lines. GOLPH3 repression resulted in the reduction of mRNA level and protein level of MMP9, accompanied with reduced phosphorylation of mTOR, EGFR and Src. Our findings suggest GOLPH3 regulate MMP9 expression which impact cell migration and invasion. This regulation is probably mediated by EGFR and Src signaling pathways.

The multiple cellular functions of the oncoprotein Golgi phosphoprotein 3

The highly conserved Golgi phosphoprotein 3 (GOLPH3) protein, a component of Trans-Golgi Network (TGN), has been defined as a "first-in-class Golgi oncoprotein" and characterized as a Phosphatidylinositol 4-phosphate [PI(4)P] effector at the Golgi. GOLPH3 is commonly amplified in several solid tumors. Furthermore this protein has been associated with poor prognosis in many cancers. Highly conserved from yeast to humans, GOLPH3 provides an essential function in vesicle trafficking and Golgi structure. Recent data have also implicated this oncoprotein in regulation of cytokinesis, modulation of mitochondrial mass and cellular response to DNA damage. A minute dissection of the molecular pathways that require GOLPH3 protein will be helpful to develop new therapeutic cancer strategies.

Increased Expression of GOLPH3 is Associated with the Proliferation of Prostate Cancer

Background: Golgi phosphoprotein 3 (GOLPH3) is a metastasis-associated gene, however its role in cell proliferation of prostate cancer (PCa) has not yet been elucidated.

Methods: The level of expression of GOLPH3 and other genes was examined by quantitative real-time PCR (QPCR) and western blot analysis. Furthermore, we performed a comprehensive analysis of the expression of GOLPH3 in PCa using a tissue microarray (TMA) and correlated our findings with pathological parameters of PCa. RNA interference (RNAi) was used to silence the expression of GOLPH3 in PC-3 cells and to measure the effects on proliferation and cell cycle using the CCK-8 assay and flow cytometry. Western blots were also employed to assess AKT-mTOR and cell cycle-related proteins.

Results: We showed that the expression of GOLPH3 was located at the trans-Golgi membranes in PCa cells. We found that GOLPH3 was expressed in all PCa cells and was significantly higher in two androgen-independent cell lines, DU145 and PC-3. TMA immunohistochemistry showed that GOLPH3 was positive in 64% of cancer tissue samples compared with 20% in normal and 30% in benign samples (P<0.05). In vitro, silencing GOLPH3 expression inhibited cell proliferation and arrested the cell cycle at the G2/M phase. Silencing GOLPH3 also activated P21 expression but suppressed the expression of CDK1/2 and cyclinB1 protein together with the phosphorylation of AKT and mTOR.

Conclusions: The expression of the GOLPH3 protein was significantly elevated in PCa. GOLPH3 can promote cell proliferation by enhancing the activity of AKT-mTOR signaling. Altogether, these findings suggest that GOLPH3 play important roles in proliferation and cell cycle regulation in PCa and might serve as promising biomarkers for PCa progression as well as potential therapeutic targets.

GOLPH3 links the Golgi, DNA damage, and cancer

GOLPH3 is the first example of an oncogene that functions in secretory trafficking at the Golgi. The discovery of GOLPH3's roles in both cancer and Golgi trafficking raises questions about how GOLPH3 and the Golgi contribute to cancer. Our recent investigation of the regulation of GOLPH3 revealed a surprising response by the Golgi upon DNA damage that is mediated by DNA-PK and GOLPH3. These results provide new insight into the DNA damage response with important implications for understanding the cellular response to standard cancer therapeutic agents.