GOLPH3 promotes glioma progression via facilitating JAK2-STAT3 pathway activation

GOLPH3 promotes calcium oxalate-induced renal injury and fibrosis through Golgi stress-mediated apoptosis and inflammatory responses

A common urological disorder, calcium oxalate (CaOx) stones are the most common form of kidney stones. Deposition of CaOx crystals leads to tubular damage, interstitial fibrosis, and chronic kidney disease. Understanding the intrinsic mechanisms of kidney stone formation is essential for the prevention of kidney stones and the development of new therapeutic agents. The Golgi apparatus is a key organelle in the secretory pathway of eukaryotic cells, which plays an important role in the sorting, modification, and transport of proteins within the cell, and has been reported to be involved in several diseases, including prostate tumors, gastrointestinal tumors, sepsis, and so on. GOLPH3 is also known as GPP34, GMx33, or MIDAS. It is a glycoprotein that regulates traffic between the trans-Golgi network and the cell membrane. However, its role in renal injury caused by CaOx crystal deposition is still unclear. Results from immunohistochemistry, qRT-PCR, western blot, and public database single nucleotide RNA-seq showed that GOLPH3 was significantly upregulated in kidney stone patients and animal kidneys. Significant inhibition of Golgi stress, apoptosis, and renal fibrosis by GOLPH3 inhibition with siRNA in CaOx-stimulated HK-2 cells. The PI3K\AKT\mTOR signaling pathway was inhibited by GOLPH3 knockdown, which may be associated with reduced inflammatory response and apoptosis, as well as restoration of Golgi morphology and function. In conclusion, GOLPH3 plays a critical role in CaOx-induced kidney injury by promoting Golgi stress and increasing inflammatory responses, apoptosis, and renal fibrosis, suggesting that GOLPH3 is a potential therapeutic target for kidney stones.

CircRNA-CIRH1A Promotes the Development of Osteosarcoma by Regulating PI3K/AKT and JAK2/STAT3 Signaling Pathways

Osteogenic sarcoma (OS), one of the mesenchymal tumors with a high degree of malignancy, mainly occurs in the metaphysis of the long bones and around the knee joints in children and adolescents. The poor diagnosis in patients with OS can be attributed to the lack of early clinical symptoms, although the growth of tumor mass gradually results in severe pain and systemic symptoms. The mechanisms underlying the pathogenesis of OS are not fully understood. Thus, identifying early diagnostic biomarkers and novel targets involved in the progression of OS is of critical significance in the management of OS. CircRNA is a class of non-coding RNAs characterized by the close-loop structure and increased stability, which are implicated in the regulation of cell proliferation, differentiation, migration, and apoptosis. Moreover, circRNAs also play significant roles in aging and chronic disorders, such as cancer and cardiovascular diseases. Accordingly, we reported the upregulation of circRNA-CIRH1A in OS tissues and cell lines. Silencing circRNA-CIRH1A in OS cell lines (U2OS, HOS, Saos-2, and MG-63) could inhibit the cell proliferation, invasion, migration, and apoptosis, which was also validated in xenograft tumorigenesis mouse model. We further demonstrated that circRNA-CIRH1A sponged miR-1276, which subsequently disrupted the effect of miR-1276 on PI3K/AKT and JAK2/STAT3 signaling pathways. Together, our study revealed the oncogenic role of circRNA-CIRH1A in OS, and identified miR-1276/ PI3K-AKT and JAK2-STAT3 signaling axis as the key downstream mediators of circRNA-CIRH1A.

PMF-GRN: a variational inference approach to single-cell gene regulatory network inference using probabilistic matrix factorization

Inferring gene regulatory networks (GRNs) from single-cell data is challenging due to heuristic limitations. Existing methods also lack estimates of uncertainty. Here we present Probabilistic Matrix Factorization for Gene Regulatory Network Inference (PMF-GRN). Using single-cell expression data, PMF-GRN infers latent factors capturing transcription factor activity and regulatory relationships. Using variational inference allows hyperparameter search for principled model selection and direct comparison to other generative models. We extensively test and benchmark our method using real single-cell datasets and synthetic data. We show that PMF-GRN infers GRNs more accurately than current state-of-the-art single-cell GRN inference methods, offering well-calibrated uncertainty estimates.

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.

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.

Long Intergenic Noncoding RNA 00641 Promotes Growth and Invasion of Colorectal Cancer through Regulating miR-450b-5p/GOLPH3 Axis

Background

Long noncoding RNAs (lncRNAs) have a vital function in tumor onset and progress. For instance, long intergenic noncoding RNA 00641 (LINC00641) has been linked to cancer modulation. Nonetheless, the precise biological roles of LINC00641 in colorectal cancer (CRC) remain elusive.

Methods

The expression levels of LINC00641 as well as the docking sites for LINC00641 and miR-450b-5p were analyzed using public data resources and web-based analytic tools. The putative downstream targets of miR-450b-5p were also predicted. Next, we evaluated the biological functions and the contents of LINC00641 in CRC both in vivo and in vitro. We next explored the influence of LINC00641 on the growth, migration, and infiltration of CRC cells via cell proliferation, migration, and invasion experiments. Besides, qRT-PCR, western blotting, flow cytometry, luciferase enzyme reporter assay, and in vivo tumorigenicity assays were conducted.

Results

Our results confirmed that LINC00641 was markedly upmodulated in CRC tissues and CRC cell lines, and the upmodulation was linked to poor survival. Notably, the proliferative and migratory abilities of HCT-116 and SW480 cells were significantly inhibited by the knockdown of LINC00641 both in vitro and in vivo, illustrating that LINC00641 exerted a tumor-promotion role in CRC. Mechanistically, LINC00641 could competitively bind miR-450b-5p, thereby expunging its inhibitory effect on GOLPH3 expression. Moreover, miR-450-5p and GOLPH3 were able to reverse LINC00641-mediated cellular processes.

Conclusions

Overall, the findings of this study suggest that LINC00641 promotes the proliferative and migratory abilities of CRC through sponging the miR-450b-5p/GOLPH3 axis.

Golgi Phosphoprotein 3 Promotes Colon Cancer Cell Metastasis Through STAT3 and Integrin α3 Pathways

Background: Golgi phosphoprotein 3 (GOLPH3) overexpression was recently reported to be associated with a poor clinical outcome in patients with colorectal cancer (CRC). However, the underlying molecular mechanism through which GOLPH3 promotes CRC metastasis remains poorly understood.

Methods:In vitro genetic ablation of GOLPH3 was performed using siRNA transfection, and a stably overexpressed GOLPH3 colon cancer cell line was constructed using the lentivirus system. Cell invasion and migration assays were conducted with or without Matrigel. Immunoblotting, qRT-PCR, immunofluorescence and immunohistochemistry were utilized to study the expression level of GOLPH3, ZEB1, integrin α3 and phosphorylation level of STAT3, AKT/mTOR and Raf/MEK/ERK pathways. Co-immunoprecipitation was used to investigate the interaction between GOLPH3 and p-STAT3 (Tyr705) or total STAT3.

Results: Overexpression of GOLPH3 was found in CRC tissues and colon cancer cell lines. Knockdown of GOLPH3 using siRNAs significantly suppressed the invasion and migration of HCT116 and HCT8 cells. In contrast, the overexpression of GOLPH3 promoted the migratory and invasive ability of colon cancer cells. The phosphorylation level of STAT3 as well as the protein and mRNA levels of ZEB1 and integrin α3, were significantly decreased after GOLPH3 knockdown. Moreover, Integrin α3 expression was correlated with GOLPH3 expression in CRC tissues. Co-immunoprecipitation assay revealed that GOLPH3 interacted with pSTAT3 (Tyr705) and total STAT3. Our further experiments suggested that GOLPH3 facilitated IL-6 induced STAT3 activation and subsequently induced transcription of integrin α3 and ZEB1, which promoted the metastasis and progression of CRC.

Conclusion: Our current work demonstrates that GOLPH3 facilitates STAT3 activation and regulates the expression of EMT transcription factor ZEB1 and Integrin α3 in colon cancer cells. These findings indicate that GOLPH3 plays a critical role in CRC metastasis and might be a new therapeutic target for CRC treatment.

C/EBPβ regulates the JAK/STAT signaling pathway in triple-negative breast cancer

C/EBPβ is a member of the CCAAT/enhancer‐binding protein (C/EBP) family, which consists of a number of b‐ZIP transcription factors. Although C/EBPβ has been implicated in the development of certain cancers, including breast cancer, it remains unknown whether dysregulation of C/EBPβ in breast cancer is subtype‐specific. Moreover, the underlying mechanisms by which C/EBPβ regulates breast cancer carcinogenesis are not fully understood. Here, we present evidence that C/EBPβ is specifically overexpressed in human TNBC samples, but not in non‐TNBC samples. C/EBPβ depletion dramatically suppressed TNBC cell growth, migration, invasion, and colony formation ability. A subsequent mechanistic study revealed that the JAK/STAT signaling pathway was upregulated in C/EBPβ_high TNBC samples compared with C/EBPβ_low TNBC samples. C/EBPβ ChIP‐seq and qPCR were performed to demonstrate that C/EBPβ directly binds to and regulates JAK/STAT signaling pathway genes in TNBC. Taken together, our data indicate the oncogenic role of C/EBPβ in human TNBC and reveal a novel mechanism by which C/EBPβ promotes TNBC carcinogenesis.

Gefitinib induces EGFR and α5β1 integrin co-endocytosis in glioblastoma cells

Overexpression of EGFR drives glioblastomas (GBM) cell invasion but these tumours remain resistant to EGFR-targeted therapies such as tyrosine kinase inhibitors (TKIs). Endocytosis, an important modulator of EGFR function, is often dysregulated in glioma cells and is associated with therapy resistance. However, the impact of TKIs on EGFR endocytosis has never been examined in GBM cells. In the present study, we showed that gefitinib and other tyrosine kinase inhibitors induced EGFR accumulation in early-endosomes as a result of an increased endocytosis. Moreover, TKIs trigger early-endosome re-localization of another membrane receptor, the fibronectin receptor alpha5beta1 integrin, a promising therapeutic target in GBM that regulates physiological EGFR endocytosis and recycling in cancer cells. Super-resolution dSTORM imaging showed a close-proximity between beta1 integrin and EGFR in intracellular membrane compartments of gefitinib-treated cells, suggesting their potential interaction. Interestingly, integrin depletion delayed gefitinib-mediated EGFR endocytosis. Co-endocytosis of EGFR and alpha5beta1 integrin may alter glioma cell response to gefitinib. Using an in vitro model of glioma cell dissemination from spheroid, we showed that alpha5 integrin-depleted cells were more sensitive to TKIs than alpha5-expressing cells. This work provides evidence for the first time that EGFR TKIs can trigger massive EGFR and alpha5beta1 integrin co-endocytosis, which may modulate glioma cell invasiveness under therapeutic treatment.

GOLPH3 Regulates EGFR in T98G Glioblastoma Cells by Modulating Its Glycosylation and Ubiquitylation

Protein trafficking is altered when normal cells acquire a tumor phenotype. A key subcellular compartment in regulating protein trafficking is the Golgi apparatus, but its role in carcinogenesis is still not well defined. Golgi phosphoprotein 3 (GOLPH3), a peripheral membrane protein mostly localized at the trans-Golgi network, is overexpressed in several tumor types including glioblastoma multiforme (GBM), the most lethal primary brain tumor. Moreover, GOLPH3 is currently considered an oncoprotein, however its precise function in GBM is not fully understood. Here, we analyzed in T98G cells of GBM, which express high levels of epidermal growth factor receptor (EGFR), the effect of stable RNAi-mediated knockdown of GOLPH3. We found that silencing GOLPH3 caused a significant reduction in the proliferation of T98G cells and an unexpected increase in total EGFR levels, even at the cell surface, which was however less prone to ligand-induced autophosphorylation. Furthermore, silencing GOLPH3 decreased EGFR sialylation and fucosylation, which correlated with delayed ligand-induced EGFR downregulation and its accumulation at endo-lysosomal compartments. Finally, we found that EGF failed at promoting EGFR ubiquitylation when the levels of GOLPH3 were reduced. Altogether, our results show that GOLPH3 in T98G cells regulates the endocytic trafficking and activation of EGFR likely by affecting its extent of glycosylation and ubiquitylation.

Human Golgi phosphoprotein 3 is an effector of RAB1A and RAB1B

Golgi phosphoprotein 3 (GOLPH3) is a peripheral membrane protein localized at the trans-Golgi network that is also distributed in a large cytosolic pool. GOLPH3 has been involved in several post-Golgi protein trafficking events, but its precise function at the molecular level is not well understood. GOLPH3 is also considered the first oncoprotein of the Golgi apparatus, with important roles in several types of cancer. Yet, it is unknown how GOLPH3 is regulated to achieve its contribution in the mechanisms that lead to tumorigenesis. Binding of GOLPH3 to Golgi membranes depends on its interaction to phosphatidylinositol-4-phosphate. However, an early finding showed that GTP promotes the binding of GOLPH3 to Golgi membranes and vesicles. Nevertheless, it remains largely unknown whether this response is consequence of the function of GTP-dependent regulatory factors, such as proteins of the RAB family of small GTPases. Interestingly, in Drosophila melanogaster the ortholog of GOLPH3 interacts with- and behaves as effector of the ortholog of RAB1. However, there is no experimental evidence implicating GOLPH3 as a possible RAB1 effector in mammalian cells. Here, we show that human GOLPH3 interacted directly with either RAB1A or RAB1B, the two isoforms of RAB1 in humans. The interaction was nucleotide dependent and it was favored with GTP-locked active state variants of these GTPases, indicating that human GOLPH3 is a bona fide effector of RAB1A and RAB1B. Moreover, the expression in cultured cells of the GTP-locked variants resulted in less distribution of GOLPH3 in the Golgi apparatus, suggesting an intriguing model of GOLPH3 regulation.

IL-22 promotes tumor growth of breast cancer cells in mice

Increased interleukin-22 (IL-22) level was reported to associate with progression of breast cancer. Regulation of IL-22 in breast cancer still needs to be elucidated. We assessed the effect of giving IL-22 in tumor growth of mice inoculated with 4T1, MCF7 and MDA-MB-231 breast cancer cells. IL-22-producing cells were analyzed in tumor tissues. We also analyzed the impact of giving IL-1β and IL-23 on IL-22 levels in tumor tissues. Giving exogenous IL-22 increased tumor size and intra-tumor Ki-67-positive cells in vivo. IL-22 increased phosphorylated STAT3 level and proliferation of breast cancer cells in vitro, an effect blocked by a STAT3-inhibitor stattic. Endogenous IL-22 mRNA level was up-regulated in tumor tissue, compared with normal mammary tissue. Innate lymphoid cell group 3 (ILC3) is a major producer of IL-22 in 4T1 tumor. Giving IL-1β and/or IL-23 increased cell proliferation in 4T1 tumor, which was reversed by concurrent use of an IL-22 neutralization antibody. IL-1β and IL-23 increased levels of IL-22 mRNA and IL-22-producing ILC3 in 4T1 tumor. Our findings suggest a mechanism for how IL-22 regulates tumor growth in breast cancer, and indicate blocking IL-22 function might reduce IL-1β- and IL-23-induced tumor progression of breast cancer.

TROY signals through JAK1-STAT3 to promote glioblastoma cell migration and resistance

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults and carries a discouraging prognosis. Its aggressive and highly infiltrative nature renders the current standard treatment of maximal surgical resection, radiation, and chemotherapy relatively ineffective. Identifying the signaling pathways that regulate GBM migration/invasion and resistance is required to develop more effective therapeutic regimens to treat GBM. Expression of TROY, an orphan receptor of the TNF receptor superfamily, increases with glial tumor grade, inversely correlates with patient overall survival, stimulates GBM cell invasion in vitro and in vivo, and increases resistance to temozolomide and radiation therapy. Conversely, silencing TROY expression inhibits GBM cell invasion, increases sensitivity to temozolomide, and prolongs survival in a preclinical intracranial xenograft model. Here, we have identified for the first time that TROY interacts with JAK1. Increased TROY expression increases JAK1 phosphorylation. In addition, increased TROY expression promotes STAT3 phosphorylation and STAT3 transcriptional activity that is dependent upon JAK1. TROY-mediated activation of STAT3 is independent of its ability to stimulate activity of NF-κB. Inhibition of JAK1 activity by ruxolitinib or knockdown of JAK1 expression by siRNA significantly inhibits TROY-induced STAT3 activation, GBM cell migration, and decreases resistance to temozolomide. Taken together, our data indicate that the TROY signaling complex may represent a potential therapeutic target with the distinctive capacity to exert effects on multiple pathways mediating GBM cell invasion and resistance.

High SOX8 expression promotes tumor growth and predicts poor prognosis through GOLPH3 signaling in tongue squamous cell carcinoma

According to our previous study, GOLPH3 is markedly up-expressed in tongue squamous cell carcinoma (TSCC), which is also associated with poor survival. However, it remains unclear about key upstream and downstream mechanisms of GOLPH3. This study aimed to illuminate new mechanisms modulating GOLPH3 upregulation and promoting TSCC development at the molecular level. Using mass spectrometry and agarose-streptavidin-biotin pull-down analyses, SOX8 (SRY-Box 8) was identified to be the new protein to bind the GOLPH3 promoter within TSCC cells, which was further verified to be the regulator of GOLPH3 upregulation. The knockdown of SOX8 suppressed the promoter activity of GOLPH3, while secondarily inhibiting TSCC cell proliferation both in vivo and in vitro. Interestingly, GOLPH3 overexpression rescued the SOX8 knockdown-mediated suppression on TSCC proliferation. Additionally, exogenous over-expression of SOX8 also activated the activity of promoter as well as GOLPH3 expression, in the meantime of promoting TSCC development. Moreover it was discovered that SOX8 regulated GOLPH3 expression through interacting with TFAP2A. Moreover our results suggested that the SOX8 level was increased within tumor tissue compared with that in para-cancer normal counterpart, which showed positive correlation with the GOLPH3 level. According to Kaplan-Meier analyses, TSCC cases having higher SOX8 and GOLPH3 expression were associated with poorer prognostic outcomes. Taken together, this study reveals that SOX8 enhances the TSCC cell growth via the direct transcriptional activation of GOLPH3, which also indicates the potential to use SOX8/GOLPH3 pathway as the treatment target among TSCC patients.

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.

MiR-3150b-3p inhibits the progression of colorectal cancer cells via targeting GOLPH3

The aim of this study was to investigate the function of miR-3150b-3p in malignant behaviors of colorectal cancer (CRC). The tumor-inhibitive effect of miR-3150b-3p was determined by cell viability, invasion, and migration assays. The influence of miR-3150b-3p on the expression of Golgi phosphoprotein 3 (GOLPH3) and Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway was evaluated by luciferase reporter, qRT-PCR and western blot analysis. MiR-3150b-3p was markedly decreased in CRC cell lines compared with colonic mucosal epithelial cell line (FHC). Furthermore, miR-3150b-3p inhibited malignant biological behaviors by targeting GOLPH3, an oncogene in CRC. Additionally, we suggested that miR-3150b-3p ameliorated CRC tumorigenesis in vitro through GOLPH3-mediated JAK2/STAT3 pathway. MiR-3150b-3p might function as a promising tumor suppressor in CRC.

Endoplasmic reticulum and Golgi stress in microcephaly

Microcephaly is a neurodevelopmental condition characterized by a small brain size associated with intellectual deficiency in most cases and is one of the most frequent clinical sign encountered in neurodevelopmental disorders. It can result from a wide range of environmental insults occurring during pregnancy or postnatally, as well as from various genetic causes and represents a highly heterogeneous condition. However, several lines of evidence highlight a compromised mode of division of the cortical precursor cells during neurogenesis, affecting neural commitment or survival as one of the common mechanisms leading to a limited production of neurons and associated with the most severe forms of congenital microcephaly. In this context, the emergence of the endoplasmic reticulum (ER) and the Golgi apparatus as key guardians of cellular homeostasis, especially through the regulation of proteostasis, has raised the hypothesis that pathological ER and/or Golgi stress could contribute significantly to cortical impairments eliciting microcephaly. In this review, we discuss recent findings implicating ER and Golgi stress responses in early brain development and provide an overview of microcephaly-associated genes involved in these pathways.

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.

The knocking down of the oncoprotein Golgi phosphoprotein 3 in T98G cells of glioblastoma multiforme disrupts cell migration by affecting focal adhesion dynamics in a focal adhesion kinase-dependent manner

Golgi phosphoprotein 3 (GOLPH3) is a conserved protein of the Golgi apparatus that in humans has been implicated in tumorigenesis. However, the precise function of GOLPH3 in malignant transformation is still unknown. Nevertheless, clinicopathological data shows that in more than a dozen kinds of cancer, including gliomas, GOLPH3 could be found overexpressed, which correlates with poor prognosis. Experimental data shows that overexpression of GOLPH3 leads to transformation of primary cells and to tumor growth enhancement. Conversely, the knocking down of GOLPH3 in GOLPH3-overexpressing tumor cells reduces tumorigenic features, such as cell proliferation and cell migration and invasion. The cumulative evidence indicate that GOLPH3 is an oncoprotein that promotes tumorigenicity by a mechanism that impact at different levels in different types of cells, including the sorting of Golgi glycosyltransferases, signaling pathways, and the actin cytoskeleton. How GOLPH3 connects mechanistically these processes has not been determined yet. Further studies are important to have a more complete understanding of the role of GOLPH3 as oncoprotein. Given the genetic diversity in cancer, a still outstanding aspect is how in this inherent heterogeneity GOLPH3 could possibly exert its oncogenic function. We have aimed to evaluate the contribution of GOLPH3 overexpression in the malignant phenotype of different types of tumor cells. Here, we analyzed the effect on cell migration that resulted from stable, RNAi-mediated knocking down of GOLPH3 in T98G cells of glioblastoma multiforme, a human glioma cell line with unique features. We found that the reduction of GOLPH3 levels produced dramatic changes in cell morphology, involving rearrangements of the actin cytoskeleton and reduction in the number and dynamics of focal adhesions. These effects correlated with decreased cell migration and invasion due to affected persistence and directionality of cell motility. Moreover, the knocking down of GOLPH3 also caused a reduction in autoactivation of focal adhesion kinase (FAK), a cytoplasmic tyrosine kinase that regulates focal adhesions. Our data support a model in which GOLPH3 in T98G cells promotes cell migration by stimulating the activity of FAK.

Hes3 Enhances the Malignant Phenotype of Lung Cancer through Upregulating Cyclin D1, Cyclin D3 and MMP7 Expression

Hes3 is a basic helix-loop-helix factor gene, which was found to be involved in neural cell differentiation. Expression and clinicopathological significance of Hes3 in non-small cell lung cancer was not clear. In this study, we used immunohistochemistry to examine Hes3 expression in normal human lung and non-small cell lung cancer tissues. Hes3 expression was detected in cytoplasm and nucleus. Hes3 expression in bronchial epithelial cells and epithelial cells of submucosal glands was relatively weak and the positive rate was of 30.3% (10/33). Hes3 expression in non-small cell lung cancer tissues (51.8% (58/112)) was significantly higher than that in normal lung tissues (p < 0.05). Hes3 expression in cancer tissues was significantly associated with poor differentiation, advanced TNM stages, lymph node metastasis, and a shorter patient survival time (p < 0.05). In vitro study showed that overexpression of Hes3 in A549 cells significantly promoted cancer cell proliferation and invasion, while inhibition of Hes3 expression significantly downregulated cancer cell proliferation and invasion (p < 0.05). Western blotting showed that overexpression of Hes3 significantly upregulated expression of Cyclin D1, Cyclin D3, and MMP7 in A549 cells, while inhibition of Hes3 expression in LK2 cells significantly downregulated the expression of these molecules (p < 0.05). These results indicated that Hes3 may contribute to the malignant phenotype of non-small cell lung cancer, possibly through regulation of Cyclin D1, Cyclin D3, and MMP7, and may be a promising cancer marker.

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.