JWA regulates TRAIL-induced apoptosis via MARCH8-mediated DR4 ubiquitination in cisplatin-resistant gastric cancer cells

Combination therapies and novel delivery systems: a new frontier in overcoming TRAIL resistance in gastric cancer

Gastric cancer (GC) presents a formidable challenge in oncology, mainly due to its inherent resistance to therapies such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). This review delineates the multifaceted mechanisms underlying TRAIL resistance in GC, encompassing the deregulation of death receptors (DRs) and decoy receptors (DcRs), aberrant signaling pathways, and the influence of the tumor microenvironment (TME). Innovative strategies such as nanoparticle-based drug delivery systems and oncolytic viral therapies are being explored to counteract these challenges. Nanoparticles enhance TRAIL delivery and efficacy by exploiting the enhanced permeability and retention (EPR) effect, while oncolytic viruses can selectively target cancer cells and stimulate immune responses. Combination therapies, integrating TRAIL with conventional chemotherapeutics like paclitaxel, cisplatin, and 5-fluorouracil, have shown promise in overcoming resistance by modulating apoptotic pathways and downregulating multidrug resistance genes. Additionally, novel agents like cyclopamine, decitabine, and genistein have emerged as effective TRAIL sensitizers by modulating apoptotic pathways and enhancing DR5 expression. Furthermore, the integration of epigenetic modifiers can restore TRAIL sensitivity by demethylating DR4 and DR5 genes. This review emphasizes the need for a comprehensive understanding of the molecular underpinnings of TRAIL resistance and the potential of combination therapies and TRAIL delivery by nanoparticles and oncolytic viruses to enhance treatment outcomes in GC. Future research should focus on elucidating predictive biomarkers and optimizing therapeutic regimens to improve the clinical efficacy of TRAIL-based strategies in GC.

miR-603 Mediates Thyroid Cancer Progression by Inhibiting HACE1-Dependent YAP1 Degradation

This study delineates the regulatory role of MicroRNA-603 (miR-603) on the molecular dynamics of HACE1 and YAP1 in thyroid cancer (TC). Using a combination of bioinformatics, dual-luciferase reporter assays, and various cellular assays, we identified that miR-603 is significantly overexpressed in TC tissues and cells. Our investigations confirmed that miR-603 targets the 3'UTR of HACE1, suppressing its expression, which in turn affects the ubiquitination and stability of the YAP1 protein. Specifically, HACE1's suppression led to decreased YAP1 degradation, promoting cellular processes associated with tumor progression, such as proliferation, migration, and invasion. These in vitro findings were corroborated by in vivo experiments in a TC xenograft model, demonstrating that miR-603 facilitates tumor growth through stabilization of YAP1 protein by targeting HACE1. These results highlight a novel miRNA-mediated pathway influencing TC pathogenesis and suggest potential targets for therapeutic intervention.

miR-335-5p Inhibits EMT and PI3K/AKT Pathways via MARCH8

Ubiquitination is a highly conserved process that regulates protein stability by post-translational modification. Membrane-associated RING-CH (MARCH) proteins belong to a family of transmembrane E3 ligases which are responsible for the degradation of their target proteins. Recently, several MARCH family members, including MARCH8, have been reported to be deregulated in cancers. However, the nuances of the exact mechanism remain unexplored. Herein, we investigated regulation of PI3K/AKT and EMT pathways in esophageal cancer via miR-335-5p/MARCH8 axis. Putative miRNAs regulating MARCH8 expression were predicted using in-silico tools. Correlation between expression of miR-335-5p and MARCH8 in esophageal cancer and distant matched non-malignant tissues was evaluated using Real-time PCR. Further, luciferase assay and western blot analysis were carried out to study the direct regulation of MARCH8 via miR-335-5p in esophageal cancer cells. Expression of MARCH8 and miR-335-5p was modulated in esophageal cancer cells and its effect on PI3K/AKT and EMT pathways was evaluated using western blot analysis. Prediction tools revealed miR-335-5p to be the most promising miRNA that might regulate MARCH8 expression. Next, expression analysis of miR-335-5p and MARCH8 in esophageal cancer and distant matched non-malignant tissues revealed an inverse correlation between miR-335-5p and MARCH8 expression (r= - 0.293; p = 0.139). A significant decrease in MARCH8 expression was observed post-miR-335-5p transfection in esophageal cancer cells (p < 0.05). The direct regulation of MARCH8 via miR-335-5p was established using luciferase assay. Further, forced expression of miR-335-5p and silencing of MARCH8 in esophageal cancer cells resulted in the inhibition of PI3/AKT and EMT pathways. Our findings for the first time, demonstrate miR-335-5p mediated regulation of PI3K/AKT and EMT pathways via MARCH8.

Role of MARCH E3 ubiquitin ligases in cancer development

Membrane-associated RING-CH (MARCH) E3 ubiquitin ligases, a family of RING-type E3 ubiquitin ligases, have garnered increased attention for their indispensable roles in immune regulation, inflammation, mitochondrial dynamics, and lipid metabolism. The MARCH E3 ligase family consists of eleven distinct members, and the dysregulation of many of these members has been documented in several human malignancies. Over the past two decades, extensive research has revealed that MARCH E3 ligases play pivotal roles in cancer progression by ubiquitinating key oncogenes and tumor suppressors and orchestrating various signaling pathways. Some MARCH E3s act as oncogenes, while others act as tumor suppressors, and the majority of MARCH E3s play both oncogenic and tumor suppressive roles in a context-dependent manner. Notably, there is special emphasis on the sole mitochondrial MARCH E3 ligase MARCH5, which regulates mitochondrial homeostasis within cancer cells. In this review, we delve into the diverse functions of MARCH E3 ligases across different cancer types, shedding light on the underlying molecular mechanisms mediating their effects, their regulatory effects on cancer and their potential as therapeutic targets.

NPR1 promotes cisplatin resistance by inhibiting PARL-mediated mitophagy-dependent ferroptosis in gastric cancer

Cisplatin-based chemotherapy serves as the standard of care for individuals with advanced stages of gastric cancer. Nevertheless, the emergence of chemoresistance in GC has detrimental impacts on prognosis, yet the underlying mechanisms governing this phenomenon remain elusive. Level of mitophagy and ferroptosis of GC cells were detected by fluorescence, flow cytometry, GSH, MDA, Fe2+ assays, and to explore the specific molecular mechanisms between NPR1 and cisplatin resistance by performing western blot and coimmunoprecipitation (co-IP) assays. These results indicates that NPR1 positively correlated with cisplatin-resistance and played a crucial part in conferring resistance to cisplatin in gastric cancer cells. Mechanistically, NPR1 affected levels of mitophagy and ferroptosis in human cisplatin-resistance GC cells with cisplatin treatment. Specifically, NPR1 inhibited mitophagy-dependent ferroptosis by reducing the ubiquitination-mediated degradation of PARL; moreover, NPR1 promoted PARL stabilization by disrupting the PARL-MARCH8 complex, which ultimately led to the development of chemoresistance in GC cells. Considering our findings, NPR1 appears to play an important role in chemotherapy for GC. NPR1 could potentially be used to overcome chemotherapy resistance.

Ubiquitination and deubiquitination in cancer: from mechanisms to novel therapeutic approaches

Ubiquitination, a pivotal posttranslational modification of proteins, plays a fundamental role in regulating protein stability. The dysregulation of ubiquitinating and deubiquitinating enzymes is a common feature in various cancers, underscoring the imperative to investigate ubiquitin ligases and deubiquitinases (DUBs) for insights into oncogenic processes and the development of therapeutic interventions. In this review, we discuss the contributions of the ubiquitin-proteasome system (UPS) in all hallmarks of cancer and progress in drug discovery. We delve into the multiple functions of the UPS in oncology, including its regulation of multiple cancer-associated pathways, its role in metabolic reprogramming, its engagement with tumor immune responses, its function in phenotypic plasticity and polymorphic microbiomes, and other essential cellular functions. Furthermore, we provide a comprehensive overview of novel anticancer strategies that leverage the UPS, including the development and application of proteolysis targeting chimeras (PROTACs) and molecular glues.

DR5 disulfide bonding as a sensor and effector of protein folding stress

New agents are needed that selectively kill cancer cells without harming normal tissues. The TRAIL ligand and its receptors, DR5 and DR4, exhibit cancer-selective toxicity, but TRAIL analogs or agonistic antibodies targeting these receptors have not received FDA approval for cancer therapy. Small molecules for activating DR5 or DR4 independently of protein ligands may bypass some of the pharmacological limitations of these protein drugs. Previously described Disulfide bond Disrupting Agents (DDAs) activate DR5 by altering its disulfide bonding through inhibition of the Protein Disulfide Isomerases (PDIs) ERp44, AGR2, and PDIA1. Work presented here extends these findings by showing that disruption of single DR5 disulfide bonds causes high-level DR5 expression, disulfide-mediated clustering, and activation of Caspase 8-Caspase 3 mediated pro-apoptotic signaling. Recognition of the extracellular domain of DR5 by various antibodies is strongly influenced by the pattern of DR5 disulfide bonding, which has important implications for the use of agonistic DR5 antibodies for cancer therapy. Disulfide-defective DR5 mutants do not activate the ER stress response or stimulate autophagy, indicating that these DDA-mediated responses are separable from DR5 activation and pro-apoptotic signaling. Importantly, other ER stressors, including Thapsigargin and Tunicamycin also alter DR5 disulfide bonding in various cancer cell lines and in some instances, DR5 mis-disulfide bonding is potentiated by overriding the Integrated Stress Response (ISR) with inhibitors of the PERK kinase or the ISR inhibitor ISRIB. These observations indicate that the pattern of DR5 disulfide bonding functions as a sensor of ER stress and serves as an effector of proteotoxic stress by driving extrinsic apoptosis independently of extracellular ligands.

JWA inhibits nicotine-induced lung cancer stemness and progression through CHRNA5/AKT-mediated JWA/SP1/CD44 axis

Cigarette smoking is an independent risk factor for lung cancer. Nicotine, as an addictive substance in tobacco and e-cigarettes, is known to promote tumor progression and metastasis despite being a non-carcinogen. As a tumor suppressor gene, JWA is widely involved in the inhibition of tumor growth and metastasis and the maintenance of cellular homeostasis, including in non-small cell lung cancer (NSCLC). However, the role of JWA in nicotine-induced tumor progression remains unclear. Here, we reported for the first time that JWA was significantly downregulated in smoking-related lung cancer and associated with overall survival. Nicotine exposure reduced JWA expression in a dose-dependent manner. Gene Set Enrichment Analysis (GSEA) analysis showed the tumor stemness pathway was enriched in smoking-related lung cancer, and JWA was negatively associated with stemness molecules CD44, SOX2, and CD133. JWA also inhibited nicotine-enhanced colony formation, spheroid formation, and EDU incorporation in lung cancer cells. Mechanically, nicotine downregulated JWA expression via the CHRNA5-mediated AKT pathway. Lower JWA expression enhanced CD44 expression through inhibition of ubiquitination-mediated degradation of Specificity Protein 1 (SP1). The in vivo data indicated that JAC4 through the JWA/SP1/CD44 axis inhibited nicotine-triggered lung cancer progression and stemness. In conclusion, JWA via down-regulating CD44 inhibited nicotine-triggered lung cancer cell stemness and progression. Our study may provide new insights to develop JAC4 for the therapy of nicotine-related cancers.

JAC4 Inhibits EGFR-Driven Lung Adenocarcinoma Growth and Metastasis through CTBP1-Mediated JWA/AMPK/NEDD4L/EGFR Axis

Lung adenocarcinoma (LUAD) is the most common lung cancer, with high mortality. As a tumor-suppressor gene, JWA plays an important role in blocking pan-tumor progression. JAC4, a small molecular-compound agonist, transcriptionally activates JWA expression both in vivo and in vitro. However, the direct target and the anticancer mechanism of JAC4 in LUAD have not been elucidated. Public transcriptome and proteome data sets were used to analyze the relationship between JWA expression and patient survival in LUAD. The anticancer activities of JAC4 were determined through in vitro and in vivo assays. The molecular mechanism of JAC4 was assessed by Western blot, quantitative real-time PCR (qRT-PCR), immunofluorescence (IF), ubiquitination assay, co-immunoprecipitation, and mass spectrometry (MS). Cellular thermal shift and molecule-docking assays were used for confirmation of the interactions between JAC4/CTBP1 and AMPK/NEDD4L. JWA was downregulated in LUAD tissues. Higher expression of JWA was associated with a better prognosis of LUAD. JAC4 inhibited LUAD cell proliferation and migration in both in-vitro and in-vivo models. Mechanistically, JAC4 increased the stability of NEDD4L through AMPK-mediated phosphorylation at Thr367. The WW domain of NEDD4L, an E3 ubiquitin ligase, interacted with EGFR, thus promoting ubiquitination at K716 and the subsequent degradation of EGFR. Importantly, the combination of JAC4 and AZD9191 synergistically inhibited the growth and metastasis of EGFR-mutant lung cancer in both subcutaneous and orthotopic NSCLC xenografts. Furthermore, direct binding of JAC4 to CTBP1 blocked nuclear translocation of CTBP1 and then removed its transcriptional suppression on the JWA gene. The small-molecule JWA agonist JAC4 plays a therapeutic role in EGFR-driven LUAD growth and metastasis through the CTBP1-mediated JWA/AMPK/NEDD4L/EGFR axis.

HPV upregulates MARCHF8 ubiquitin ligase and inhibits apoptosis by degrading the death receptors in head and neck cancer

The membrane-associated RING-CH-type finger ubiquitin ligase MARCHF8 is a human homolog of the viral ubiquitin ligases Kaposi's sarcoma herpesvirus K3 and K5 that promote host immune evasion. Previous studies have shown that MARCHF8 ubiquitinates several immune receptors, such as the major histocompatibility complex II and CD86. While human papillomavirus (HPV) does not encode any ubiquitin ligase, the viral oncoproteins E6 and E7 are known to regulate host ubiquitin ligases. Here, we report that MARCHF8 expression is upregulated in HPV-positive head and neck cancer (HNC) patients but not in HPV-negative HNC patients compared to normal individuals. The MARCHF8 promoter is highly activated by HPV oncoprotein E6-induced MYC/MAX transcriptional activation. The knockdown of MARCHF8 expression in human HPV-positive HNC cells restores cell surface expression of the tumor necrosis factor receptor superfamily (TNFRSF) death receptors, FAS, TRAIL-R1, and TRAIL-R2, and enhances apoptosis. MARCHF8 protein directly interacts with and ubiquitinates the TNFRSF death receptors. Further, MARCHF8 knockout in mouse oral cancer cells expressing HPV16 E6 and E7 augments cancer cell apoptosis and suppresses tumor growth in vivo. Our findings suggest that HPV inhibits host cell apoptosis by upregulating MARCHF8 and degrading TNFRSF death receptors in HPV-positive HNC cells.

Identification of potentially functional modules and diagnostic genes related to amyotrophic lateral sclerosis based on the WGCNA and LASSO algorithms

Amyotrophic lateral sclerosis (ALS) is a genetically and phenotypically heterogeneous disease results in the loss of motor neurons. Mounting information points to involvement of other systems including cognitive impairment. However, neither the valid biomarker for diagnosis nor effective therapeutic intervention is available for ALS. The present study is aimed at identifying potentially genetic biomarker that improves the diagnosis and treatment of ALS patients based on the data of the Gene Expression Omnibus. We retrieved datasets and conducted a weighted gene co-expression network analysis (WGCNA) to identify ALS-related co-expression genes. Functional enrichment analysis was performed to determine the features and pathways of the main modules. We then constructed an ALS-related model using the least absolute shrinkage and selection operator (LASSO) regression analysis and verified the model by the receiver operating characteristic (ROC) curve. Besides we screened the non-preserved gene modules in FTD and ALS-mimic disorders to distinct ALS-related genes from disorders with overlapping genes and features. Altogether, 4198 common genes between datasets with the most variation were analyzed and 16 distinct modules were identified through WGCNA. Blue module had the most correlation with ALS and functionally enriched in pathways of neurodegeneration-multiple diseases', 'amyotrophic lateral sclerosis', and 'endocytosis' KEGG terms. Further, some of other modules related to ALS were enriched in 'autophagy' and 'amyotrophic lateral sclerosis'. The 30 top of hub genes were recruited to a LASSO regression model and 5 genes (BCLAF1, GNA13, ARL6IP5, ARGLU1, and YPEL5) were identified as potentially diagnostic ALS biomarkers with validating of the ROC curve and AUC value.

APAF1-Binding Long Noncoding RNA Promotes Tumor Growth and Multidrug Resistance in Gastric Cancer by Blocking Apoptosome Assembly

Chemotherapeutics remain the first choice for advanced gastric cancers (GCs). However, drug resistance and unavoidable severe toxicity lead to chemotherapy failure and poor prognosis. Long noncoding RNAs (lncRNAs) play critical roles in tumor progression in many cancers, including GC. Here, through RNA screening, an apoptotic protease-activating factor 1 (APAF1)-binding lncRNA (ABL) that is significantly elevated in cancerous GC tissues and an independent prognostic factor for GC patients is identified. Moreover, ABL overexpression inhibits GC cell apoptosis and promotes GC cell survival and multidrug resistance in GC xenograft and organoid models. Mechanistically, ABL directly binds to the RNA-binding protein IGF2BP1 via its KH1/2 domain, and then IGF2BP1 further recognizes the METTL3-mediated m6A modification on ABL, which maintains ABL stability. In addition, ABL can bind to the WD1/WD2 domain of APAF1, which competitively prevent cytochrome c from interacting with APAF1, blocking apoptosome assembly and caspase-9/3 activation; these events lead to resistance to cell death in GC cells. Intriguingly, targeting ABL using encapsulated liposomal siRNA can significantly enhance the sensitivity of GC cells to chemotherapy. Collectively, the results suggest that ABL can be a potential prognostic biomarker and therapeutic target in GC.

Targeting JWA for Cancer Therapy: Functions, Mechanisms and Drug Discovery

Simple Summary

JWA has been identified as a potential therapeutic target for several cancers. In this review, we summarize the tumor suppressive functions of the JWA gene and its role in anti-cancer drug development. The focus is on elucidating the key regulatory proteins up and downstream of JWA and their signaling networks. We also discuss current strategies for targeting JWA (JWA peptides, small molecule agonists, and JWA-targeted Pt (IV) prodrugs).

Abstract

Tumor heterogeneity limits the precision treatment of targeted drugs. It is important to find new tumor targets. JWA, also known as ADP ribosylation factor-like GTPase 6 interacting protein 5 (ARL6IP5, GenBank: AF070523, 1998), is a microtubule-associated protein and an environmental response gene. Substantial evidence shows that JWA is low expressed in a variety of malignancies and is correlated with overall survival. As a tumor suppressor, JWA inhibits tumor progression by suppressing multiple oncogenes or activating tumor suppressor genes. Low levels of JWA expression in tumors have been reported to be associated with multiple aspects of cancer progression, including angiogenesis, proliferation, apoptosis, metastasis, and chemotherapy resistance. In this review, we will discuss the structure and biological functions of JWA in tumors, examine the potential therapeutic strategies for targeting JWA and explore the directions for future investigation.

Membrane-associated RING-CH protein (MARCH8) is a novel glycolysis repressor targeted by miR-32 in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer and leading cause of cancer-related deaths worldwide. Aberrant cellular metabolism is a hallmark of cancer cells, and disturbed metabolism showed clinical significance in CRC. The membrane-associated RING-CH 8 (MARCH8) protein, the first MARCH E3 ligase, plays an oncogenic role and serves as a prognostic marker in multiple cancers, however, the role of MARCH8 in CRC is unclear. In the present study, we aimed to investigate the biomarkers and their underlying mechanism for CRC.

METHOD

In this study, we first examined the function of MARCH8 in CRC by analysing public database. Besides, we performing gene silencing studies and generating cellular overexpression and xenograft models. Then its protein substrate was identified and validated. In addition, the expression of MARCH8 was investigated in tissue samples from CRC patients, and the molecular basis for decreased expression was analysed.

RESULTS

Systematic analysis reveals that MARCH8 is a beneficial prognostic marker in CRC. In CRC, MARCH8 exhibited tumor-suppressive activity both in vivo and in vitro. Furthermore, we found that MARCH8 is negatively correlated with hexokinase 2 (HK2) protein in CRC patients. MARCH8 regulates glycolysis and promotes ubiquitination-mediated proteasome degradation to reduces HK2 protein levels. Then HK2 inhibitor partially rescues the effect of MARCH8 knockdown in CRC. Poised chromatin and elevated miR-32 repressed MARCH8 expression.

CONCLUSION

In summary, we propose that in CRC, poised chromatin and miR-32 decrease the expression of MARCH8, further bind and add ubiquitin, induce HK2 degradation, and finally repress glycolysis to promote tumor suppressors in CRC.

JAC1 targets YY1 mediated JWA/p38 MAPK signaling to inhibit proliferation and induce apoptosis in TNBC

Triple negative breast cancer (TNBC) is a type of breast cancer with poor prognosis, and has no ideal therapeutic target and ideal medicine. Downregulation of JWA is closely related to the poor overall survival in many cancers including TNBC. In this study, we reported at the first time that JWA gene activating compound 1 (JAC1) inhibited the proliferation of TNBC in vitro and in vivo experimental models. JAC1 specifically bound to YY1 and eliminated its transcriptional inhibition of JWA gene. The rescued JWA induced G1 phase arrest and apoptosis in TNBC cells through the p38 MAPK signaling pathway. JAC1 also promoted ubiquitination and degradation of YY1. In addition, JAC1 disrupted the interaction between YY1 and HSF1, and suppressed the oncogenic role of HSF1 in TNBC through p-Akt signaling pathway. In conclusion, JAC1 suppressed the proliferation of TNBC through the JWA/P38 MAPK signaling and YY1/HSF1/p-Akt signaling. JAC1 maybe a potential therapeutic agent for TNBC.

JWA suppresses proliferation in trastuzumab-resistant breast cancer by downregulating CDK12

Breast cancer is the most common cancer worldwide. JWA is a microtubule-associated protein that has been identified as a tumor suppressor, and its downregulation in tumors is an independent adverse prognostic factor. The objective of this study was to explore the expression, regulation, and mechanism of JWA in trastuzumab-resistant breast cancers. In this study, we found that JWA expression was lower in trastuzumab-resistant breast cancers than that in trastuzumab-sensitive breast cancers. Furthermore, it was confirmed that overexpression of JWA inhibited proliferation and promoted apoptosis in trastuzumab-resistant breast cancers both in vitro and in vivo. In addition, the low expression of JWA in trastuzumab-resistant breast cancers is associated with a poor prognosis. Combining RNA-sequence datasets and next-generation sequencing, it was found that JWA negatively regulated CDK12, and was involved in the G1-to-S transition of the cell cycle. It has been reported that CDK12 drives breast cancer initiation and induces trastuzumab resistance. Taken together, high expression of JWA could inhibit the growth of trastuzumab-resistant breast cancer, and JWA is a potential predictive marker for trastuzumab resistance. In addition, targeted therapy with JWA may be a novel therapeutic strategy to improve the survival rate of trastuzumab-resistant breast cancer.

Induction of ferroptosis by ATF3 elevation alleviates cisplatin resistance in gastric cancer by restraining Nrf2/Keap1/xCT signaling

Background

Currently, resistance against cisplatin (DDP) is a frequent problem for the success of advanced gastric carcinoma (GC) chemotherapy. Here, we sought to investigate the function of activating transcription factor 3 (ATF3) n GC chemoresistance.

Methods

Expression of ATF3 was determined in GC cell lines (MNK45, SGC7901, and BGC823) and cisplatin (DDP)-resistant cells (SGC7901/DDP and BGC823/DDP). Biological informatics was performed to analyze ATF3 expression and prognosis in GC patients. Cisplatin resistance was evaluated. Ferroptosis was detected after ATF3 transfection of cells. The underlying molecular mechanism was also investigated.

Results

Transcripts of ATF3 were decreased in GC cells and GC tissues. Kaplan–Meier plotter analysis revealed that ATF3 expression was positively related to the overall survival of GC patients. In particular, lower levels of ATF3 were observed in cisplatin-resistant SGC7901/DDP and BGC823/DDP relative to their parental cells. Notably, ATF3 elevation sensitized cisplatin-resistant cells to cisplatin. Mechanically, compared with parental cells, SGC7901/DDP and BGC823/DDP cells exhibited lower ferroptosis evident by lower ROS, MDA and lipid peroxidation and higher intracellular GSH levels. However, ATF3 elevated ferroptosis in SGC7901/DDP and BGC823/DDP cells. Intriguingly, ATF3 overexpression together with ferroptosis activator erastin or RSL3 treatment further enhanced ferroptosis and cisplatin resistance; however, the ferroptosis suppressor liproxstatin-1 reversed the function of ATF3 in ferroptosis and cisplatin resistance. Additionally, cisplatin-resistant cells exhibited stronger activation of Nrf2/Keap1/xCT signaling relative to parental cells, which was restrained by ATF3 up-regulation. Importantly, restoring Nrf2 signaling overturned ATF3-mediated ferroptosis and cisplatin resistance.

Conclusion

ATF3 may sensitize GC cells to cisplatin by induction of ferroptosis via blocking Nrf2/Keap1/xCT signaling, supporting a promising therapeutic approach for overcoming chemoresistance in GC.

Functional roles of E3 ubiquitin ligases in gastric cancer

To date, >650 E3 ubiquitin ligases have been described in humans, including >600 really interesting new genes (RINGs), 28 homologous to E6-associated protein C-terminus (HECTs) and several RING-in-between-RINGs. They are considered key regulators and therapeutic targets of many types of human cancers, including gastric cancer (GC). Among them, some RING and HECT E3 ligases are closely related to the proliferation, infiltration and prognosis of GC. During the past few years, abnormal expressions and functions of many E3 ligases have been identified in GC. However, the functional roles of E3 ligases in GC have not been fully elucidated. The present article focuses on the functional roles of E3 ligases related to the proteasome in GC. In this comprehensive review, the latest research progress on E3 ligases involved in GC and elaborate their structure, classification, functional roles and therapeutic value in GC was summarized. Finally, 30 E3 ligases that serve essential roles in regulating the development of GC were described. Some of these ligases may serve as oncogenes or tumor suppressors in GC, whereas the pathological mechanism of others needs further study; for example, constitutive photomorphogenic 1. In conclusion, the present review demonstrated that E3 ligases are crucial tumor regulatory factors and potential therapeutic targets in GC. Therefore, more studies should focus on the therapeutic targeting of E3 ligases in GC.

Natural Product Mediated Regulation of Death Receptors and Intracellular Machinery: Fresh from the Pipeline about TRAIL-Mediated Signaling and Natural TRAIL Sensitizers

Rapidly developing resistance against different therapeutics is a major stumbling block in the standardization of therapy. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated signaling has emerged as one of the most highly and extensively studied signal transduction cascade that induces apoptosis in cancer cells. Rapidly emerging cutting-edge research has helped us to develop a better understanding of the signaling machinery involved in inducing apoptotic cell death. However, excitingly, cancer cells develop resistance against TRAIL-induced apoptosis through different modes. Loss of cell surface expression of TRAIL receptors and imbalance of stoichiometric ratios of pro- and anti-apoptotic proteins play instrumental roles in rewiring the machinery of cancer cells to develop resistance against TRAIL-based therapeutics. Natural products have shown excellent potential to restore apoptosis in TRAIL-resistant cancer cell lines and in mice xenografted with TRAIL-resistant cancer cells. Significantly refined information has previously been added and continues to enrich the existing pool of knowledge related to the natural-product-mediated upregulation of death receptors, rebalancing of pro- and anti-apoptotic proteins in different cancers. In this mini review, we will set spotlight on the most recently published high-impact research related to underlying mechanisms of TRAIL resistance and how these deregulations can be targeted by natural products to restore TRAIL-mediated apoptosis in different cancers.

MicroRNA regulation of TRAIL mediated signaling in different cancers: Control of micro steering wheels during the journey from bench-top to the bedside

Large-scale sequencing methodologies have helped us identify numerous genomic alterations and we have started to scratch the surface of many new targets for treatment of cancer and the associated predictive biomarkers. TRAIL (TNF-related apoptosis-inducing ligand) is a highly appreciated anti-cancer molecule because of its ability to selectively target cancer cells. However, confluence of information suggests that cancer cells develop resistance against TRAIL-based therapeutics. It is being realized that overexpression of anti-apoptotic proteins and inactivation of pro-apoptotic proteins significantly impairs TRAIL triggered apoptosis, particularly in clinical settings. Re-balancing of pro-and anti-apoptotic proteins and upregulation of death receptors with functionally active extrinsic and intrinsic apoptotic pathways are necessary to sensitize cancer cells to TRAIL based therapeutics. microRNAs (miRNAs) are involved in regulation of myriad of molecular processes and characterized into oncogenic and tumor suppressor miRNAs. Accumulating data has identified miRNAs which positively or negatively regulate TRAIL mediated signaling in cancer cells, helping us understand different steps at which TRAIL-mediated apoptotic signaling can be targeted. Here, we assess the status of our understanding of the mechanisms related to miRNA regulation of TRAIL mediated signaling, as well as the existing gaps therein, and discuss the challenges and opportunities that will help us get closer to personalized medicine.

Stathmin gene silencing suppresses proliferation, migration and invasion of gastric cancer cells via AKT/sCLU and STAT3 signaling

Globally, gastric cancer is the fifth most common malignancy, with high rates of incidence and mortality. The high mortality rate and poor prognosis of gastric cancer are closely associated with its profound invasiveness, high incidence of metastasis, rapid proliferation, and high rate of recurrence. Previous studies have confirmed that stathmin (STMN) has an important role in the occurrence, development and prognosis of gastric cancer. However, the detailed mechanisms by which STMN affects these processes remain unclear. The aim of the present study was to determine how STMN promotes invasion, migration and proliferation in gastric cancer tumor cells. The results of immunohistochemistry indicated that STMN is overexpressed in stomach neoplasm tissues, and that it is associated with migration, invasion, proliferation and anti‑apoptotic states of gastric cancer cells. The secretory proteins of gastric cancer cells with or without STMN knockdown were further analyzed using the isobaric tags for relative and absolute quantitation method to identify differentially expressed proteins verified by reverse transcription‑quantitative polymerase chain reaction and western blot analysis. Inhibition of STMN decreases the levels of clusterin, cystatin C and matrix metalloproteinases, followed by inhibiting the protein kinase B and signal transducer and activation of transcription activation. These findings suggest that STMN could be a promising therapeutic target for gastric cancer.

The roles of ubiquitination in extrinsic cell death pathways and its implications for therapeutics

Regulation of cell survival and death, including apoptosis and necroptosis, is important for normal development and tissue homeostasis, and disruption of these processes can cause cancer, inflammatory diseases, and degenerative diseases. Ubiquitination is a cellular process that induces proteasomal degradation by covalently attaching ubiquitin to the substrate protein. In addition to proteolytic ubiquitination, nonproteolytic ubiquitination, such as M1-linked and K63-linked ubiquitination, has been shown to be important in recent studies, which have demonstrated its function in cell signaling pathways that regulate inflammation and cell death pathways. In this review, we summarize the TRAIL- and TNF-induced death receptor signaling pathways along with recent advances in this field and illustrate how different types of ubiquitination control cell death and survival. In particular, we provide an overview of the different types of ubiquitination, target residues, and modifying enzymes, including E3 ligases and deubiquitinating enzymes. Given the relevance of these regulatory pathways in human disease, we hope that a better understanding of the regulatory mechanisms of cell death pathways will provide insights into and therapeutic strategies for related diseases.

RNF138 confers cisplatin resistance in gastric cancer cells via activating Chk1 signaling pathway

Chemotherapy resistance represents a major issue associated with gastric cancer (GC) treatment, and arises through multiple mechanisms, including modulation of the cell-cycle check point. Several ubiquitin kinases, including RING finger protein 138 (RNF138), have been reported to mediate the G2/M phase arrest. In this study, we investigated the role of RNF138 in the development of cisplatin resistance of two GC cell lines. We show that RNF138 levels are higher in cisplatin-resistant cell lines, compared with cisplatin-sensitive cells, and RNF138 expression was elevated during drug withdrawal following the cisplatin treatment. Using gene overexpression and silencing, we analyzed the impact of altering RNF138 level on GC cell viability, apoptosis, and cell cycle phenotypes in two isogenic cisplatin-sensitive and resistant cell lines. We show that RNF138 overexpression increased GC cell viability, decreased apoptosis and delayed cell cycle progression in the cisplatin-sensitive GC cells. Conversely, RNF138 silencing produced opposite phenotypes in the cisplatin-resistant cells. Moreover, RNF138-dependent phosphorylation of Chk1 was seen in GC cells, indicating a novel connection between cisplatin-induced DNA damage and apoptosis. Collectively, these data suggest that RNF138 modulates the cisplatin resistance in the GC cells, thus serving as a potential drug target to challenge chemotherapy failure. In addition, RNF138 can also be used as a marker to monitor the development of cisplatin resistance in GC treatment.

Antihypertensive drug-candesartan attenuates TRAIL resistance in human lung cancer via AMPK-mediated inhibition of autophagy flux

Angiotensin II type 1 receptor blockers (ARBs) are widely used as antihypertensive drugs. Candesartan is an ARB that has also been known for its anticancer effects but the exact molecular mechanism is remaining elusive. In this research, we showed for the first time that candesartan treatment significantly sensitized human lung adenocarcinoma cells to Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis by targeting TRAIL-DR5. TRAIL selectively kills cancer cells by binding to death receptors on the cell membrane, beyond the levels causing minimal toxicity in normal cells. However, some non-small-cell lung carcinoma (NSCLC) patients are resistant to TRAIL treatment in clinical trials due to inactivation of the death receptors during cytoprotective autophagy. The molecular mechanisms underlying candesartan-induced TRAIL-mediated apoptosis involved the downstream of AMPK phosphorylation resulting inhibition of autophagy flux, recruitment of death receptor 5 (DR5) and activation of apoptotic caspase cascade. Candesartan treatment also inhibits the expression of anti-apoptotic protein c-FLIP. Furthermore, blocking DR5 signaling using DR5 siRNA negatively regulated the apoptotic pathway and also induced autophagy flux, demonstrating the cytoprotective role of autophagy responsible for treatment resistance. This suggests that candesartan can be used to sensitize tumors to TRAIL treatment and may represent a useful strategy for human adenocarcinoma patients to overcome TRAIL resistance. Candesartan in combination with TRAIL also could be a novel therapeutic treatment for patients presenting both conditions of hypertension and lung cancer.

Astrocytic JWA deletion exacerbates dopaminergic neurodegeneration by decreasing glutamate transporters in mice

Astrocytic JWA exerts neuroprotective roles by alleviating oxidative stress and inhibiting inflammation. However, the molecular mechanisms of how astrocytic JWA is involved in dopaminergic neurodegeneration in Parkinson's disease (PD) remain largely unknown. In this study, we found that astrocyte-specific JWA knockout mice (JWA CKO) exacerbated dopamine (DA) neuronal loss and motor dysfunction, and reduced the levels of DA and its metabolites in a 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine/probenecid (MPTP/p)-induced PD model. Astrocytic JWA deficiency repressed expression of excitatory amino-acid transporter 2 (GLT-1) and glutamate uptake both in vivo and in vitro. Further, the regulation of GLT-1 expression was involved in JWA-triggered activation of the MAPK and PI3K signaling pathways. JWA-increased GLT-1 expression was abolished by inhibitors of MEK and PI3K. Silencing CREB also abrogated JWA-increased GLT-1 expression and glutamate uptake. Additionally, JWA deficiency activated glial fibrillary acidic protein (GFAP), and increased the expression of STAT3. Similarly to the MPTP model, paraquat (PQ) exposure produced PD-like phenotypes in JWA CKO mice. Taken together, our findings provide novel insights into astrocytic JWA function in the pathogenesis of neurotoxin mouse models of PD.