Golgi Phosphoprotein Research Articles

GOLPH3 inhibition overcomes cisplatin resistance by restoring the glutathione/reactive oxygen species balance in the A549 non‑small cell lung cancer cell line.

Cisplatin resistance is common in non‑small cell lung cancer (NSCLC); however, the molecular mechanisms remain unclear. The present study aimed to identify a new function of Golgi phosphoprotein 3 (GOLPH3) in NSCLC‑associated cisplatin resistance. Using A549 human NSCLC cells and the cisplatin‑resistant variant, stable cell lines with GOLPH3 knockdown or overexpression were established using lentiviral vectors. Through Cell Counting Kit‑8 and EdU assays, it was revealed that knockdown of GOLPH3 significantly enhanced cisplatin sensitivity in NSCLC cells. Specifically, flow cytometric analysis showed that GOLPH3 knockdown promoted apoptosis and G2‑phase cell cycle arrest in A549 cells. Mechanistically, intracellular reactive oxygen species (ROS) and glutathione (GSH) levels were measured using assay kits, and it was demonstrated that GOLPH3 knockdown decreased intracellular GSH levels, and further attenuated intracellular cisplatin efflux and GSH/ROS imbalance. In addition, tumor‑sphere formation assays verified that GOLPH3 knockdown mitigated the stem cell‑like phenotype of NSCLC cells. In conclusion, the present findings indicated the relevance of GOLPH3 in NSCLC‑associated cisplatin resistance, and thus targeting GOLPH3 may be developed into a combination therapy to overcome cisplatin resistance.

GOLPH3 knockdown alleviates the inflammation and apoptosis in lipopolysaccharide-induced acute lung injury by inhibiting Golgi stress mediated autophagy

Pneumonia, an acute inflammatory lesion of the lung, is the leading cause of death in children aged < 5 years. We aimed to study the function and mechanism of Golgi phosphoprotein 3 (GOLPH3) in infantile pneumonia. Lipopolysaccharide (LPS)-induced acute lung injury (ALI) mice and injury of MLE-12 cells were used as the pneumonia model in vitro. After GOLPH3 was knocked down, the histopathological changes of lung tissues were assessed by hematoxylin-eosin (H&E) staining. The Wet/Dry ratio of lung tissues was calculated. The enzyme-linked immunosorbent assay (ELISA) method was used to detecte the contents of inflammatory factors in bronchoalveolar lavage fluid (BALF). The damaged DNA in apoptotic cells in lung tissues was tested by Terminal deoxynucleotidyl transferase-mediated dUTP Nick end labeling (TUNEL) staining. Immunofluorescence staining analyzed LC3II and Golgi matrix protein 130 (GM130) expression in lung tissues and MLE-12 cells. The apoptosis of MLE-12 cells was measured by flow cytometry analysis. Additionally, the expression of proteins related to apoptosis, autophagy and Golgi stress was examined with immunoblotting. Results indicated that GOLPH3 knockdown alleviated lung tissue pathological changes in LPS-triggered ALI mice. LPS-induced inflammation and apoptosis in lung tissues and MLE-12 cells were remarkably alleviated by GOLPH3 deficiency. Besides, GOLPH3 depletion suppressed autophagy and Golgi stress in lung tissues and MLE-12 cells challenged with LPS. Moreover, Rapamycin (Rap), an autophagy inhibitor, counteracted inflammation and apoptosis inhibited by GOLPH3 silencing in LPS-induced MLE-12 cells. Furthermore, brefeldin A (BFA) pretreatment apparently abrogated the inhibitory effect of GOLPH3 knockdown on autophagy in MLE-12 cells exposed to LPS. To be concluded, GOLPH3 knockdown exerted lung protective effect against LPS-triggered inflammation and apoptosis by inhibiting Golgi stress mediated autophagy.

GOLPH3 inhibits erastin-induced ferroptosis in colorectal cancer cells.

Ferroptosis is a novel form of programmed cell death and is considered to be a druggable target for colorectal cancer (CRC) therapy. However, the role of ferroptosis in CRC and its underlying mechanism are not fully understood. In the present study we found that a protein enriched in the Golgi apparatus, Golgi phosphoprotein 3 (GOLPH3), was overexpressed in human CRC tissue and in several CRC cell lines. The expression of GOLPH3 was significantly correlated with the expression of ferroptosis-related genes in CRC. The overexpression of GOLPH3 in Erastin-induced Caco-2 CRC cells reduced ferroptotic phenotypes, whereas the knockdown of GOLPH3 potentiated ferroptosis in HT-29 CRC cells. GOLPH3 induced the expression of prohibitin-1 (PHB1) and prohibitin-2 (PHB2), which also inhibited ferroptosis in Erastin-treated CRC cells. Moreover, GOLPH3 interacted with PHB2 and nuclear factor erythroid 2-related factor 2 (NRF2) in Caco-2 cells. These observations indicate that GOLPH3 is a negative regulator of ferroptosis in CRC cells. GOLPH3 protects these cells from ferroptosis by inducing the expression of PHB1 and PHB2, and by interacting with PHB2 and NRF2.

Chromosomal 3q amplicon encodes essential regulators of secretory vesicles that drive secretory addiction in cancer.

Cancer cells exhibit heightened secretory states that drive tumor progression. Here, we identify a chromosome 3q amplicon that serves as a platform for secretory regulation in cancer. The 3q amplicon encodes multiple Golgi-resident proteins, including the scaffold Golgi integral membrane protein 4 (GOLIM4) and the ion channel ATPase Secretory Pathway Ca2+ Transporting 1 (ATP2C1). We show that GOLIM4 recruits ATP2C1 and Golgi phosphoprotein 3 (GOLPH3) to coordinate calcium-dependent cargo loading and Golgi membrane bending and vesicle scission. GOLIM4 depletion disrupts the protein complex, resulting in a secretory blockade that inhibits the progression of 3q-amplified malignancies. In addition to its role as a scaffold, GOLIM4 maintains intracellular manganese (Mn) homeostasis by binding excess Mn in the Golgi lumen, which initiates the routing of Mn-bound GOLIM4 to lysosomes for degradation. We show that Mn treatment inhibits the progression of multiple types of 3q-amplified malignancies by degrading GOLIM4, resulting in a secretory blockade that interrupts pro-survival autocrine loops and attenuates pro-metastatic processes in the tumor microenvironment. Potentially underlying the selective activity of Mn against 3q-amplified malignancies, ATP2C1 co-amplification increases Mn influx into the Golgi lumen, resulting in a more rapid degradation of GOLIM4. These findings show that functional cooperativity between co-amplified genes underlies heightened secretion and a targetable secretory addiction in 3q-amplified malignancies.

GOLPH3 promotes tumor malignancy via inhibition of ferroptosis by upregulating SLC7A11 in cholangiocarcinoma.

Golgi phosphoprotein 3 (GOLPH3) has been reported as an oncogene in various tumors; however, the role and function of GOLPH3 and its relevant molecular mechanism in cholangiocarcinoma (CCA) are unclear. Herein, GOLPH3 expression in CCA tissues was observed to be significantly higher than that in paired adjacent noncancerous tissues. Clinicopathological analysis showed that GOLPH3 expression correlated positively with the tumor-node-metastasis stage. In addition, GOLPH3 expression correlated inversely with the overall survival of patients with CCA. Multivariate analysis showed that GOLPH3 was an independent prognostic factor for patients with CCA. Transcriptome analysis (RNA sequencing) of GOLPH3 knockdown cells showed that the expression levels of nine ferroptosis-related genes were significantly changed, indicating the important biological function of GOLPH3 in ferroptosis in CCA cells. Furthermore, GOLPH3 knockdown could significantly promote Erastin-induced ferroptosis in vitro and suppress tumor growth in vivo. Overexpression of GOLPH3 had the opposite effect on this phenotype. Further studies revealed that GOLPH3 knockdown was significantly associated with a decrease in cysteine content, an accumulation of the lipid peroxidation product malondialdehyde, an increase in reactive oxygen species, and sensitized CCA cells to Erastin-induced ferroptosis. Moreover, changes in GOLPH3 expression were found to be consistent with the expression of light chain subunit solute carrier family 7 member 11 (SLC7A11). Thus, our study suggested that GOLPH3 functions as an oncoprotein in CCA and may suppress ferroptosis by facilitating SLC7A11 expression, suggesting that GOLPH3 could serve as a therapeutic target for CCA treatment.

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.

Using Drosophila melanogaster to Dissect the Roles of the mTOR Signaling Pathway in Cell Growth.

The evolutionarily conserved target of rapamycin (TOR) serine/threonine kinase controls eukaryotic cell growth, metabolism and survival by integrating signals from the nutritional status and growth factors. TOR is the catalytic subunit of two distinct functional multiprotein complexes termed mTORC1 (mechanistic target of rapamycin complex 1) and mTORC2, which phosphorylate a different set of substrates and display different physiological functions. Dysregulation of TOR signaling has been involved in the development and progression of several disease states including cancer and diabetes. Here, we highlight how genetic and biochemical studies in the model system Drosophila melanogaster have been crucial to identify the mTORC1 and mTORC2 signaling components and to dissect their function in cellular growth, in strict coordination with insulin signaling. In addition, we review new findings that involve Drosophila Golgi phosphoprotein 3 in regulating organ growth via Rheb-mediated activation of mTORC1 in line with an emerging role for the Golgi as a major hub for mTORC1 signaling.

Comparative analysis of GOLPH3 expression in lymph node-positive prostate cancer: immunohistochemistry staining patterns and clinical significance.

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men worldwide. Lymph node metastasis is a poor prognostic factor for PCa. Previous studies have found that Golgi phosphoprotein 3 (GOLPH3) is overexpressed in various cancers, including PCa. We examined GOLPH3 expression in PCa cells from primary tumor and, as the first, also in metastatic lymph nodes to assess its potential as a new risk factor for PCa progression. The study included 78 patients diagnosed with lymph node-positive PCa confirmed in the postoperative material. All the patients underwent radical prostatectomy (RP) with extended lymphadenectomy. The clinical data of the patients were retrospectively analyzed, and their histopathological specimens were selected for further analysis. Immunohistochemistry (IHC) staining was performed and the expression of GOLPH3 was assessed by an experienced uropathologist using an immunoreactive scale (IRS). A correlational analysis of the obtained data with the clinicopathological data of patients was performed. A positive IHC reaction for GOLPH3 was observed in all samples. IRS score for GOLPH3 expression was higher in the metastatic lymph nodes than in the prostate (not statistically significant; p=0.056). Several significant correlations were identified in connection with GOLPH3 expression levels in the prostate and metastatic lymph node tissues. No significant correlations were found between GOLPH3 expression and patient characteristics (e.g. BMI, EAU risk group, or preoperative PSA level), pathological features, or postoperative outcomes. However, we found that lymphovascular invasion (LVI) tended to be more common in patients with a higher percentage of GOLPH3-positive cells (p=0.02). We also found a positive association between the intensity of GOLPH3 staining in metastatic lymph nodes and the EAU classification. Finally, we found a significant negative correlation between the GOLPH3 expression and the efficacy of RP - the higher the expression of GOLPH3, the lower the efficacy of RP was (p<0.05). GOLPH3 is expressed in both prostate and metastatic lymph nodes, with higher expression in metastatic lymph nodes. High GOLPH3 expression was associated with the occurrence of LVI, higher-risk group in the EAU classification, and lower efficacy of the RP, but there was no significant correlation with other pathological features or postoperative outcomes.

Tetramethylpyrazine ameliorates endotoxin-induced acute lung injury by relieving Golgi stress via the Nrf2/HO-1 signaling pathway

PurposeEndotoxin-induced acute lung injury (ALI) is a severe disease caused by an imbalanced host response to infection. It is necessary to explore novel mechanisms for the treatment of endotoxin-induced ALI. In endotoxin-induced ALI, tetramethylpyrazine (TMP) provides protection through anti-inflammatory, anti-apoptosis, and anti-pyroptosis effects. However, the mechanism of action of TMP in endotoxin-induced ALI remains unclear. Here, we aimed to determine whether TMP can protect the lungs by inhibiting Golgi stress via the Nrf2/HO-1 pathway.Methods and resultsUsing lipopolysaccharide (LPS)-stimulated C57BL/6J mice and MLE12 alveolar epithelial cells, we observed that TMP pretreatment attenuated endotoxin-induced ALI. LPS + TMP group showed lesser lung pathological damage and a lower rate of apoptotic lung cells than LPS group. Moreover, LPS + TMP group also showed decreased levels of inflammatory factors and oxidative stress damage than LPS group (P < 0.05). Additionally, LPS + TMP group presented reduced Golgi stress by increasing the Golgi matrix protein 130 (GM130), Golgi apparatus Ca2+/Mn2+ ATPases (ATP2C1), and Golgin97 expression while decreasing the Golgi phosphoprotein 3 (GOLPH3) expression than LPS group (P < 0.05). Furthermore, TMP pretreatment promoted Nrf2 and HO-1 expression (P < 0.05). Nrf2-knockout mice or Nrf2 siRNA-transfected MLE12 cells were pretreated with TMP to explore how the Nrf2/HO-1 pathway affected TMP-mediated Golgi stress in endotoxin-induced ALI models. We observed that Nrf2 gene silencing partially reversed the alleviating effect of Golgi stress and the pulmonary protective effect of TMP.ConclusionOur findings showed that TMP therapy reduced endotoxin-induced ALI by suppressing Golgi stress via the Nrf2/HO-1 signaling pathway in vivo and in vitro.

GOLPH3 promotes endotoxemia-induced liver and kidney injury through Golgi stress-mediated apoptosis and inflammatory response

Sepsis is a serious clinical condition characterized by a systemic inflammatory response, a leading cause of acute liver and kidney injury, and is associated with a high morbidity and mortality. Understanding the molecular mechanisms underlying the acute liver and kidney injury is crucial for developing an effective therapy. Golgi apparatus plays important roles and has various substrates mediating cellular stress responses. Golgi phosphoprotein 3 (GOLPH3), linking Golgi membranes to the cytoskeleton, has been identified as an important oncogenic regulator; however, its role in endotoxemia-induced acute liver and kidney injury remains elusive. Here, we found that upregulation of GOLPH3 was associated with endotoxemia-induced acute liver and kidney injury. Lipopolysaccharide (LPS) treatment increased Golgi stress and fragmentation, and associated pro-inflammatory mediator (Tnfα, IL-6, and IL-1β) production in vivo and in vitro. Interestingly, the downregulation of GOLPH3 significantly decreased LPS-induced Golgi stress and pro-inflammatory mediators (Tnfα, IL-6, Mcp1, and Nos2), and reversed apoptotic cell deaths in LPS-treated hepatocytes and renal tubular cells. GOLPH3 knockdown also reduced inflammatory response in LPS-treated macrophages. The AKT/NF-kB signaling pathway was suppressed in GOLPH3 knockdown, which may be associated with a reduction of inflammatory response and apoptosis and the recovery of Golgi morphology and function. Taken together, GOLPH3 plays a crucial role in the development and progression of acute liver and kidney injury by promoting Golgi stress and increasing inflammatory response and apoptosis, suggesting GOLPH3 as a potential therapeutic target for endotoxemia-induced tissue injury.

GP73 enhances the ox-LDL-induced inflammatory response in THP-1 derived macrophages via affecting NLRP3 inflammasome signaling

BackgroundAtherosclerosis is a chronic inflammatory disease with its molecular basis incompletely understood. Here, we determined whether the Golgi phosphoprotein 73 (GP73), a novel protein highly related to inflammation and disrupted lipid metabolism, was involved in the development of atherosclerosis. MethodsPublic microarray databases of human vascular samples were analyzed for expression patterns. Apolipoprotein-E-gene-deficient (ApoE−/−) mice (8-week-old) were randomly assigned to either a chow diet group or a high-fat diet group. The levels of serum GP73, lipid profiles and key inflammatory cytokines were determined by ELISA. The aortic root plaque was isolated and used for by Oil Red O staining. PMA-differentiated THP-1 macrophages were transfected with GP73 small interfering RNA (siRNA) or infected with adenovirus expressing GP73, and then stimulated with oxidized low density lipoprotein (ox-LDL). The expressions of pro-inflammatory cytokines and signal pathway key targets were determined by ELISA kit and Western blot respectively. In addition, ichloro-dihydro-fluorescein diacetate (DCFH-DA) was used to measure the intracellular ROS levels. ResultsThe expressions of GP73 and NLRP3 were substantially upregulated in human atherosclerotic lesions. There were significant linear correlations between GP73 and inflammatory cytokines expressions. High-fat diet-induced atherosclerosis and increased levels of plasma inflammatory mediators (IL-1β, IL-18, and TNF-α) were observed in ApoE−/− mice. Besides, the expressions of GP73 in the aorta and serum were significantly upregulated and positively correlated with the NLRP3 expression. In the THP-1 derived macrophages, ox-LDL treatment upregulated the expressions of GP73 and NLRP3 proteins and activated the inflammatory responses in a concentration-dependent and time-dependent manner. Silencing of GP73 attenuated the inflammatory response and rescued the decreased migration induced by ox-LDL, inhibiting the NLRP3 inflammasome signaling and the ROS and p-NF-κB activation. ConclusionsWe demonstrated that GP73 promoted the ox-LDL-induced inflammation in macrophages by affecting the NF-κB/NLRP3 inflammasome signaling, and may play a role in atherosclerosis.

1331 Regulation of fibronectin production by Golgi phosphoprotein 3 (GOLPH3) in dermal fibroblasts

1331 Regulation of fibronectin production by Golgi phosphoprotein 3 (GOLPH3) in dermal fibroblasts

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.

Golgi signalling proteins GOLPH3, MYO18A, PITPNC1 and RAB1B: implications in prognosis and survival outcomes of AML patients

Background The role of different Golgi signalling proteins remains unexplored in the progression and spread of acute myeloid leukaemia (AML), whom all interact together in a way that facilitates proliferation and differentiation of myeloid lineage cells. Objective Since Golgi apparatus acts as master brain in membrane trafficking and signalling events that affect cell polarity necessary for migration, division, or differentiation; this study aims to explore the association between signalling proteins and the diagnosis, prognosis, and survival of AML patients. Material and methods This study comprised 70 newly diagnosed AML patients and 20 healthy controls to investigate the serum levels of signalling proteins; Golgi Phosphoprotein 3 (GOLPH3), Myosin 18A (MYO18A), Cytoplasmic Phosphatidylinositol Transfer Protein 1 (PITPNC1) and Ras-Associated Binding Protein 1B (RAB1B). Results AML patients showed higher serum levels of GOLPH3, MYO18A, PITPNC1 and RAB1B when compared to control (p < 0.001). A significant negative correlation was found between the patients’ overall survival and GOLPH3 (p = 0.001), MYO18A (p = 0.011), PITPNC1 (p = 0.001) and RAB1B (p = 0.042). Results were confirmed by Kaplen–Meier survival analysis showing lower survival estimates in patients with higher GOLPH3 (p = 0.014), MYO18A (p = 0.047), PITPNC1 (p = 0.008) and RAB1B (p = 0.033) serum levels. Conclusion GOLPH3, MYO18A, PITPNC1 and RAB1B maybe promising diagnostic and prognostic biomarkers in AML patients.

Development of a Golgi-targeted superoxide anion fluorescent probe for elucidating protein GOLPH3 function in myocardial ischemia-reperfusion injury

Superoxide anion (O2•-) is an important reactive oxygen species (ROS) and participates in various physiological and pathological processes in the organism. The O2•- burst induced by ischemia-reperfusion (I/R) is associated with cardiovascular disease and promotes the cell apoptosis. In this work, a turn-on type Golgi-targeting fluorescent probe Gol-Cou-O2•- was rationally designed for sensitive and selective detection of O2•-. The minimum detection limit concentration for O2•- was about 3.9 × 10−7 M in aqueous solution. Gol-Cou-O2•- showed excellent capacity of detecting exogenous and endogenous O2•- in living cells and zebrafish, and was also used to capture the up-regulated O2•- level during the duration of I/R process in cardiomyocytes. Golgi Phosphoprotein 3 (GOLPH3) is a potential Golgi stress marker protein and plays a key role in cells apoptosis during I/R. The fluorescence imaging and flow cytometry assay results indicated that silencing GOLPH3 through siRNA could give rise to the down-regulated O2•- level and alleviation of apoptosis in I/R myocardial cells. Thus, development of Gol-Cou-O2•- provides a diagnostic tool for myocardial oxidative stress injury and distinct insights on roles of GOLPH3 in myocardial I/R injury.

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 protein controls organ growth by interacting with TOR signaling proteins in Drosophila

The oncoprotein GOLPH3 (Golgi phosphoprotein 3) is an evolutionarily conserved phosphatidylinositol 4-phosphate effector, mainly localized to the Golgi apparatus, where it supports organelle architecture and vesicular trafficking. Overexpression of human GOLPH3 correlates with poor prognosis in several cancer types and is associated with enhanced signaling downstream of mTOR (mechanistic target of rapamycin). However, the molecular link between GOLPH3 and mTOR remains elusive. Studies in Drosophila melanogaster have shown that Translationally controlled tumor protein (Tctp) and 14-3-3 proteins are required for organ growth by supporting the function of the small GTPase Ras homolog enriched in the brain (Rheb) during mTORC1 (mTOR complex 1) signaling. Here we demonstrate that Drosophila GOLPH3 (dGOLPH3) physically interacts with Tctp and 14-3-3ζ. RNAi-mediated knockdown of dGOLPH3 reduces wing and eye size and enhances the phenotypes of Tctp RNAi. This phenotype is partially rescued by overexpression of Tctp, 14-3-3ζ, or Rheb. We also show that the Golgi localization of Rheb in Drosophila cells depends on dGOLPH3. Consistent with dGOLPH3 involvement in Rheb-mediated mTORC1 activation, depletion of dGOLPH3 also reduces levels of phosphorylated ribosomal S6 kinase, a downstream target of mTORC1. Finally, the autophagy flux and the expression of autophagic transcription factors of the TFEB family, which anti correlates with mTOR signaling, are compromised upon reduction of dGOLPH3. Overall, our data provide the first in vivo demonstration that GOLPH3 regulates organ growth by directly associating with mTOR signaling proteins.

Knockdown of circGOLPH3 inhibits cell progression and glycolysis by targeting miR-145-5p/lysine demethylase 2A (KDM2A) axis in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is one of the most common head and neck malignancies. The aim of this study is to explore the role of circRNA Golgi phosphoprotein 3 (GOLPH3) (circGOLPH3) in OSCC. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were performed to detect changes in the levels of circGOLPH3, microRNA-145-5p (miR-145-5p), and lysine demethylase 2A (KDM2A). The functions of circGOLPH3 were assessed using in vitro and in vivo assays. Dual-luciferase reporter assay detected the interaction of miR-145-5p with circGOLPH3 or KDM2A. circGOLPH3 expression was upregulated in OSCC. circGOLPH3 downregulation inhibited cell growth, metastasis, and glycolysis in vitro, and in vivo experiments revealed that circGOLPH3 inhibited tumor growth. In addition, circGOLPH3 bound to miR-145-5p and competitively inhibited KDM2A expression, thereby regulating OSCC cell behaviors as well as glycolysis. circGOLPH3 exerted pro-oncogenic effects through the miR-145-5p/KDM2A axis to regulate OSCC cell behaviors.

Golgi Phosphoprotein 3 Regulates the Physical Association of Glycolipid Glycosyltransferases.

Glycolipid glycosylation is an intricate process that mainly takes place in the Golgi by the complex interplay between glycosyltransferases. Several features such as the organization, stoichiometry and composition of these complexes may modify their sorting properties, sub-Golgi localization, enzymatic activity and in consequence, the pattern of glycosylation at the plasma membrane. In spite of the advance in our comprehension about physiological and pathological cellular states of glycosylation, the molecular basis underlying the metabolism of glycolipids and the players involved in this process remain not fully understood. In the present work, using biochemical and fluorescence microscopy approaches, we demonstrate the existence of a physical association between two ganglioside glycosyltransferases, namely, ST3Gal-II (GD1a synthase) and β3GalT-IV (GM1 synthase) with Golgi phosphoprotein 3 (GOLPH3) in mammalian cultured cells. After GOLPH3 knockdown, the localization of both enzymes was not affected, but the fomation of ST3Gal-II/β3GalT-IV complex was compromised and glycolipid expression pattern changed. Our results suggest a novel control mechanism of glycolipid expression through the regulation of the physical association between glycolipid glycosyltransferases mediated by GOLPH3.

Golgi phosphoprotein 3 promotes ovarian cancer progression and is associated with cisplatin resistance.

Golgi phosphoprotein-3 (GOLPH 3) is involved in the development of several human cancers. However, the clinical significance and biological role of GOLPH 3 in ovarian cancer (OC) remains unknown. The expression of GOLPH 3 in OC cell lines was quantified using real-time quantitative polymerase chain reaction (RT-qPCR) and western blot assays. The role of GOLPH 3 in tumorigenicity, migration, and invasion of OC cell lines by small interference RNA, scratch wound-healing assays, and transwell assays was detected. In addition, western blotting was used to determine whether GOLPH 3 is associated with the PI3K/AKT/mTOR signaling pathway. Furthermore, RT-qPCR verified whether GOLPH 3 is associated with drug resistance. GOLPH 3-positive expression rate was higher in OC. Downregulation of GOLPH 3 markedly inhibited the migration and invasion and may be related to the PI3K/AKT/mTOR signal pathway. Moreover, the result of the experiment proved that GOLPH 3 enhances the sensitivity of OC to cisplatin by regulating ATP7A/B. GOLPH 3 promoted the invasion and migration of OC, and the mechanism may be related to the PI3K/Akt/mTOR pathway. In addition, inhibition of GOLPH 3 increased the sensitivity of OC cells to cisplatin, which may be associated with ATP7A/B. This study found that GOLPH3 may promote the migration and invasion of OC cells through PI3K/Akt/mTOR pathway. At the same time, low expression of GOLPH3 increased the sensitivity of OC cells to cisplatin.