Golgi tethering factor golgin-97 suppresses breast cancer cell invasiveness by modulating NF-κB activity

EGF-mediated Golgi dynamics and cell migration require CARP2

In mammalian cells, the Golgi exists in ribbon architecture-individual stacks laterally linked to each other by tubular structures. Golgi architecture changes dynamically to cater to cellular needs. Loss of architecture is linked with pathological conditions like cancer and neurodegeneration. Not much is known about the regulators of Golgi dynamics. Here, we demonstrate that CARP2 (caspase-8- and caspase-10-associated RING-containing protein 2), an endosomal ubiquitin ligase and a known regulator of cell migration, modulates Golgi dynamics. Epidermal growth factor (EGF) treatment modestly increases CARP2 protein and disperses Golgi. An exogenous supply of CARP2 also leads to Golgi dispersal. Conversely, Golgi remains intact in CARP2 knockout (KO) cells upon EGF treatment. CARP2 variants defective in either endosomal association or ligase activity are unable to affect Golgi dispersal. Importantly, CARP2 targets Golgin45 for ubiquitination and degradation in EGF-stimulated cells. Collectively, our findings unravel the existence of crosstalk between endosomal ubiquitin signaling and Golgi dynamics.

GCC2 promotes non-small cell lung cancer progression by maintaining Golgi apparatus integrity and stimulating EGFR signaling pathways

Fundamental changes in intracellular processes, such as overactive growth signaling pathways, are common in carcinomas and are targets of many cancer therapeutics. GRIP and coiled-coil containing 2 (GCC2) is a trans-Golgi network (TGN) golgin maintaining Golgi apparatus structure and regulating vesicle transport. Here, we found an aberrant overexpression of GCC2 in non-small cell lung cancer (NSCLC) and conducted shRNA-mediated gene knockdown to investigate the role of GCC2 in NSCLC progression. shRNA-mediated GCC2 knockdown suppressed NSCLC cell growth, migration, stemness, and epithelial-mesenchymal transition (EMT) in vitro and tumor growth in vivo. In addition, GCC2 knockdown suppressed cancer cell exosome secretion and the oncogenic capacity of cancer cell-derived exosomes. Mechanistically, GCC2 inhibition decreased epidermal growth factor receptor (EGFR) expression and downstream growth and proliferation signaling. Furthermore, GCC2 inhibition compromised Golgi structural integrity in cancer cells, indicating a functional role of GCC2 in regulating intracellular trafficking and signaling to promote lung cancer progression. Together, these findings suggest GCC2 as a potential therapeutic target for the treatment of NSCLC.

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.

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.

Inhibition of Golgi stress alleviates sepsis-induced cardiomyopathy by reducing inflammation and apoptosis

BACKGROUND

Sepsis is often accompanied by multiple organ dysfunction, in which the incidence of cardiac injury is about 60%, and is closely related to high mortality. Recent studies have shown that Golgi stress is involved in liver injury, kidney injury, and lung injury in sepsis. However, whether it is one of the key mechanisms of sepsis-induced cardiomyopathy (SIC) is still unclear. The aim of this study is to investigate whether Golgi stress mediates SIC and the specific mechanism.

METHODS

Sepsis model of male C57BL/6J mice was established by cecal ligation and puncture. To observe the effect of Golgi stress on SIC, mice were injected with Golgi stimulant (Brefeldin A) or Golgi inhibitor (Glutathione), respectively. The 7-day survival rate of mice were recorded, and myocardial injury indicators including cardiac function, myocardial enzymes, myocardial pathological tissue score, myocardial inflammatory factors, and apoptosis were detected. The morphology of Golgi was observed by immunofluorescence, and the Golgi stress indices including GM-130, GOLPH3 and Goligin97 were detected by WB and qPCR.

RESULTS

After CLP, the cardiac function of mice was impaired and the levels of myocardial enzymes were significantly increased. Golgi stress was accompanied by increased myocardial inflammation and apoptosis. Moreover, the expressions of morphological proteins GM-130 and Golgin97 were decreased, and the expression of stress protein GOLPH3 was increased. In addition, Brefeldin A increased 7-day mortality and the above indicators in mice. The use of glutathione improves all of the above indicators.

CONCLUSION

Golgi stress mediates SIC, and the inhibition of Golgi stress can improve SIC by inhibiting apoptosis and inflammation.

Connexin 43 mediated collective cell migration is independent of Golgi orientation

Cell migration is vital for multiple physiological functions and is involved in the metastatic dissemination of tumour cells in various cancers. For effective directional migration, cells often reorient their Golgi apparatus and, therefore, the secretory traffic towards the leading edge. However, not much is understood about the regulation of Golgi's reorientation. Herein, we address the role of gap junction protein Connexin 43 (Cx43), which connects cells, allowing the direct exchange of molecules. We utilized HeLa WT cells lacking Cx43 and HeLa 43 cells, stably expressing Cx43, and found that functional Cx43 channels affected Golgi morphology and reduced the reorientation of Golgi during cell migration. Although the migration velocity of the front was reduced in HeLa 43, the front displayed enhanced coherence in movement, implying an augmented collective nature of migration. On BFA treatment, Golgi was dispersed and the high heterogeneity in inter-regional front velocity of HeLa WT cells was reduced to resemble the HeLa 43. HeLa 43 had higher vimentin expression and stronger basal F-actin. Furthermore, non-invasive measurement of basal membrane height fluctuations revealed a lower membrane tension. We, therefore, propose that reorientation of Golgi is not the major determinant of migration in the presence of Cx43, which induces collective-like coherent migration in cells.

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.

New insights into the role of the Golgi apparatus in the pathogenesis and therapeutics of human diseases

The Golgi apparatus is an essential cellular organelle that mediates homeostatic functions, including vesicle trafficking and the post-translational modification of macromolecules. Its unique stacked structure and dynamic functions are tightly regulated, and several Golgi proteins play key roles in the functioning of unconventional protein secretory pathways triggered by cellular stress responses. Recently, an increasing number of studies have implicated defects in Golgi functioning in human diseases such as cancer, neurodegenerative, and immunological disorders. Understanding the extraordinary characteristics of Golgi proteins is important for elucidating its associated intracellular signaling mechanisms and has important ramifications for human health. Therefore, analyzing the mechanisms by which the Golgi participates in disease pathogenesis may be useful for developing novel therapeutic strategies. This review articulates the structural features and abnormalities of the Golgi apparatus reported in various diseases and the suspected mechanisms underlying the Golgi-associated pathologies. Furthermore, we review the potential therapeutic strategies based on Golgi function.

Golgi Complex: A Signaling Hub in Cancer

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

Shedding Light on NF-κB Functions in Cellular Organelles

NF-κB is diffusely recognized as a transcriptional factor able to modulate the expression of various genes involved in a broad spectrum of cellular functions, including proliferation, survival and migration. NF-κB is, however, also acting outside the nucleus and beyond its ability to binds to DNA. NF-κB is indeed found to localize inside different cellular organelles, such as mitochondria, endoplasmic reticulum, Golgi and nucleoli, where it acts through different partners in mediating various biological functions. Here, we discuss the relationship linking NF-κB to the cellular organelles, and how this crosstalk between cellular organelles and NF-κB signalling may be evaluated for anticancer therapies.

Endogenous and Exogenous Regulatory Signaling in the Secretory Pathway: Role of Golgi Signaling Molecules in Cancer

The biosynthetic transport route that constitutes the secretory pathway plays a fundamental role in the cell, providing to the synthesis and transport of around one third of human proteins and most lipids. Signaling molecules within autoregulatory circuits on the intracellular membranes of the secretory pathway regulate these processes, especially at the level of the Golgi complex. Indeed, cancer cells can hijack several of these signaling molecules, and therefore also the underlying regulated processes, to bolster their growth or gain more aggressive phenotypes. Here, we review the most important autoregulatory circuits acting on the Golgi, emphasizing the role of specific signaling molecules in cancer. In fact, we propose to draw awareness to highlight the Golgi-localized regulatory systems as potential targets in cancer therapy.

Sec22b Regulates Inflammatory Responses by Controlling the Nuclear Translocation of NF-κB and the Secretion of Inflammatory Mediators

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) regulate the vesicle transport machinery in phagocytic cells. Within the secretory pathway, Sec22b is an endoplasmic reticulum-Golgi intermediate compartment (ERGIC)-resident SNARE that controls phagosome maturation and function in macrophages and dendritic cells. The secretory pathway controls the release of cytokines and may also impact the secretion of NO, which is synthesized by the Golgi-active inducible NO synthase (iNOS). Whether ERGIC SNARE Sec22b controls NO and cytokine secretion is unknown. Using murine bone marrow-derived dendritic cells, we demonstrated that inducible NO synthase colocalizes with ERGIC/Golgi markers, notably Sec22b and its partner syntaxin 5, in the cytoplasm and at the phagosome. Pharmacological blockade of the secretory pathway hindered NO and cytokine release, and inhibited NF-κB translocation to the nucleus. Importantly, RNA interference-mediated silencing of Sec22b revealed that NO and cytokine production were abrogated at the protein and mRNA levels. This correlated with reduced nuclear translocation of NF-κB. We also found that Sec22b co-occurs with NF-κB in both the cytoplasm and nucleus, pointing to a role for this SNARE in the shuttling of NF-κB. Collectively, our data unveiled a novel function for the ERGIC/Golgi, and its resident SNARE Sec22b, in the production and release of inflammatory mediators.

Alterations of Golgi Structural Proteins and Glycosylation Defects in Cancer

As the central hub in the secretory and endocytic pathways, the Golgi apparatus continually receives the flow of cargos and serves as a major processing station in the cell. Due to its dynamic nature, a sophisticated and constantly remodeling mechanism needs to be set up to maintain the Golgi architecture and function in the non-stop trafficking of proteins and lipids. Abundant evidence has been accumulated that a well-organized Golgi structure is required for its proper functions, especially protein glycosylation. Remarkably, altered glycosylation has been a hallmark of most cancer cells. To understand the causes of Golgi defects in cancer, efforts have been made to characterize Golgi structural proteins under physiological and pathological conditions. This review summarizes the current knowledge of crucial Golgi structural proteins and their connections with tumor progression. We foresee that understanding the Golgi structural and functional defects may help solve the puzzle of whether glycosylation defect is a cause or effect of oncogenesis.

Heme oxygenase-1(HO-1) regulates Golgi stress and attenuates endotoxin-induced acute lung injury through hypoxia inducible factor-1α (HIF-1α)/HO-1 signaling pathway

Sepsis caused acute lung injury (ALI) is a kind of serious disease in critically ill patients with very high morbidity and mortality. Recently, it has been demonstrated that Golgi is involved in the process of oxidative stress. However, whether Golgi stress is associated with oxidative stress in septic induced acute lung injury has not been elucidated. In this research, we found that lipopolysaccharide (LPS) induced oxidative stress, apoptosis, inflammation and Golgi morphology changes in acute lung injury both in vivo and in vitro. The knockout of heme oxygenase-1(HO-1) aggravated oxidative stress, inflammation, apoptosis and reduced the expression of Golgi matrix protein 130 (GM130), mannosidase Ⅱ, Golgi-associated protein golgin A1 (Golgin 97), and increased the expression of Golgi phosphoprotein 3 (GOLPH3), which caused the fragmentation of Golgi. Furtherly, the activation of hypoxia inducible factor-1α (HIF-1α)/HO-1 pathway, attenuates Golgi stress and oxidative stress by increasing the levels of GM130, mannosidase Ⅱ, Golgin 97, and decreasing the expression of GOLPH3 both in vivo and in vitro. Therefore, the activation of HO-1 plays a crucial role in alleviating sepsis-induced acute lung injury by regulating Golgi stress, oxidative stress, which may provide a therapeutic target for the treatment of acute lung injury.

Golgi-associated Rab GTPases implicated in autophagy

Autophagy is a conserved cellular degradation process in eukaryotes that facilitates the recycling and reutilization of damaged organelles and compartments. It plays a pivotal role in cellular homeostasis, pathophysiological processes, and diverse diseases in humans. Autophagy involves dynamic crosstalk between different stages associated with intracellular vesicle trafficking. Golgi apparatus is the central organelle involved in intracellular vesicle trafficking where Golgi-associated Rab GTPases function as important mediators. This review focuses on the recent findings that highlight Golgi-associated Rab GTPases as master regulators of autophagic flux. The scope for future research in elucidating the role and mechanism of Golgi-associated Rab GTPases in autophagy and autophagy-related diseases is discussed further.

Comparative bioinformatics analysis of prognostic and differentially expressed genes in non-muscle and muscle invasive bladder cancer

Bladder cancer (BC) is classified into non-muscle (NMIBC) and muscle invasive (MIBC) diseases. Several molecular alterations were previously associated with NMIBC and MIBC, but few studies have systematically compared the molecular differences between these subtypes. Here, we analyzed prognostic and differentially expressed genes in NMIBC and MIBC, using an integrative bioinformatics approach. These genes were used in functional enrichment and co-expression protein interaction (COPI) network analyses to reveal common and exclusive biological functions involved in NMIBC and MIBC. In NMIBC, the enriched functions were related to oxidative stress response, cell cycle, glutathione metabolism, ubiquitination and protein translation. Conversely, enriched functions in MIBC were extracellular matrix organization, cell migration and actin cytoskeleton. Several genes in NMIBC did not overlap with those reported to MIBC, suggesting these subtypes may have distinct underlying mechanisms. Particularly, MIBC genes were enriched for functions involved in cell migration and invasion, which could help to molecularly differentiate NMIBC and MIBC. The analysis of COPI networks disclosed high centrality nodes that may be essential for NMIBC and MIBC. Further research will determine to which extent NMIBC and MIBC share common biological functions and identify potential candidates for the differential diagnosis, prognosis and treatment of NMIBC and MIBC. SIGNIFICANCE: This study has systematically compared prognostic and differentially expressed genes between non-muscle (NMIBC) and muscle invasive (MIBC) bladder cancer, using an integrative bioinformatics approach. Many genes and biological functions were exclusively associated with either NMIBC or MIBC, suggesting that these disease subtypes could be driven by distinct molecular mechanisms. Particularly, prognostic and differentially expressed genes in MIBC were involved in cell migration and invasion, which can help to molecularly differentiate the NMIBC and MIBC subtypes. Moreover, the analysis of co-expression protein interaction networks identified high centrality nodes that could be potential candidates for the prognosis and treatment of NMIBC and MIBC.

Selected Golgi-Localized Proteins and Carcinogenesis: What Do We Know?

The role of the Golgi apparatus in carcinogenesis still remains unclear. A number of structural and functional cis-, medial-, and trans-Golgi proteins as well as a complexity of metabolic pathways which they mediate may indicate a central role of the Golgi apparatus in the development and progression of cancer. Pleiotropy of cellular function of the Golgi apparatus makes it a "metabolic heart" or a relay station of a cell, which combines multiple signaling pathways involved in carcinogenesis. Therefore, any damage to or structural abnormality of the Golgi apparatus, causing its fragmentation and/or biochemical dysregulation, results in an up- or downregulation of signaling pathways and may in turn promote tumor progression, as well as local nodal and distant metastases. Three alternative or parallel models of spatial and functional Golgi organization within tumor cells were proposed: (1) compacted Golgi structure, (2) normal Golgi structure with its increased activity, and (3) the Golgi fragmentation with ministacks formation. Regardless of the assumed model, the increased activity of oncogenesis initiators and promoters with inhibition of suppressor proteins results in an increased cell motility and migration, increased angiogenesis, significantly activated trafficking kinetics, proliferation, EMT induction, decreased susceptibility to apoptosis-inducing factors, and modulating immune response to tumor cell antigens. Eventually, this will lead to the increased metastatic potential of cancer cells and an increased risk of lymph node and distant metastases. This chapter provided an overview of the current state of knowledge of selected Golgi proteins, their role in cytophysiology as well as potential involvement in tumorigenesis.