Chromatin remodeling induced by ARID1A loss in lung cancer promotes glycolysis and confers JQ1 vulnerability

The current status and future trends of BET research in oncology

Background

BET family proteins are important epigenetic and transcriptional regulators involved in the control of tumorigenesis and development and have become important targets for cancer therapy. However, there is no systematic bibliometric analysis in this field. A visual analysis of the research hotspots and trends of BET is helpful to understand the future development direction.

Method

We used CiteSpace, VOSviewer, and Excel to visualize and analyze the trends regarding authors, journals, countries or regions, highly cited papers, and keywords in the field.

Result

The results included a total of 946 publications. There are many more papers on BET proteins published since 2013. The papers are mainly from 44 countries, led by the U.S. and China. A total of 7381 authors were identified, among which Bradner, J.E. had the greatest number of articles and the greatest influence. Cancer Discovery was the journal with the most citations per article. Our analysis identified the most influential papers in the field, including highly cited papers and citation burst references. The most frequent keywords included 'expression', 'c-Myc', 'cancer', 'BRD4', 'BET inhibition', 'resistance', 'differentiation', and 'JQ1', which represent the focus of current and developing research fields.

Conclusion

Research on BET is thriving. Collaboration and exchanges between countries and institutions must be strengthened in the future, and the mechanisms of BET-related pathways, the relationship between BET and various diseases, and the development of new BET inhibitors have become the major focus of current research and the trend of future research.

Preclinical evidence in the assembly of mammalian SWI/SNF complexes: Epigenetic insights and clinical perspectives in human lung disease therapy

The SWI/SNF complex, also known as the BRG1/BRM-associated factor (BAF) complex, represents a critical regulator of chromatin remodeling mechanisms in mammals. It is alternatively referred to as mSWI/SNF and has been suggested to be imbalanced in human disease compared with human health. Three types of BAF assemblies associated with it have been described, including (1) canonical BAF (cBAF), (2) polybromo-associated BAF (PBAF), and (3) non-canonical BAF (ncBAF) complexes. Each of these BAF assemblies plays a role, either functional or dysfunctional, in governing gene expression patterns, cellular processes, epigenetic mechanisms, and biological processes. Recent evidence increasingly links the dysregulation of mSWI/SNF complexes to various human non-malignant lung chronic disorders and lung malignant diseases. This review aims to provide a comprehensive general state-of-the-art and a profound examination of the current understanding of mSWI/SNF assembly processes, as well as the structural and functional organization of mSWI/SNF complexes and their subunits. In addition, it explores their intricate functional connections with potentially dysregulated transcription factors, placing particular emphasis on molecular and cellular pathogenic processes in lung diseases. These processes are reflected in human epigenome aberrations that impact clinical and therapeutic levels, suggesting novel perspectives on the diagnosis and molecular therapies for human respiratory diseases.

Proteomic insights into the regulatory function of ARID1A in colon cancer cells

The AT-rich interacting domain-containing protein 1A (ARID1A) is a tumor suppressor gene that has been implicated in several cancers, including colorectal cancer (CRC). The present study used a proteomic approach to elucidate the molecular mechanisms of ARID1A in CRC carcinogenesis. Stable ARID1A-overexpressing SW48 colon cancer cells were established using lentivirus transduction and the successful overexpression of ARID1A was confirmed by western blotting. Label-free quantitative proteomic analysis using liquid chromatography-tandem mass spectrometry identified 705 differentially altered proteins in the ARID1A-overexpressing cells, with 310 proteins significantly increased and 395 significantly decreased compared with empty vector control cells. Gene Ontology enrichment analysis highlighted the involvement of the altered proteins mainly in the Wnt signaling pathway. Western blotting supported these findings, as a decreased protein expression of Wnt target genes, including c-Myc, transcription factor T cell factor-1/7 and cyclin D1, were observed in ARID1A-overexpressing cells. Among the altered proteins involved in the Wnt signaling pathway, the interaction network analysis revealed that ARID1A exhibited a direct interaction with E3 ubiquitin-protein ligase zinc and ring finger 3 (ZNRF3), a negative regulator of the Wnt signaling pathway. Further analyses using the The Cancer Genome Atlas colon adenocarcinoma public dataset revealed that ZNRF3 expression significantly impacted the overall survival of patients with CRC and was positively correlated with ARID1A expression. Finally, an increased level of ZNRF3 in ARID1A-overexpressing cells was confirmed by western blotting. In conclusion, the findings of the present study suggest that ARID1A negatively regulates the Wnt signaling pathway through ZNRF3, which may contribute to CRC carcinogenesis.

Single-cell transcriptome analysis revealed heterogeneity in glycolysis and identified IGF2 as a therapeutic target for ovarian cancer subtypes

BACKGROUND

As the most malignant tumor of the female reproductive system, ovarian cancer (OC) has garnered increasing attention. The Warburg effect, driven by glycolysis, accounts for tumor cell proliferation under aerobic conditions. However, the metabolic heterogeneity linked to glycolysis in OC remains elusive.

METHODS

We integrated single-cell data with OC to score glycolysis level in tumor cell subclusters. This led to the identification of a subcluster predominantly characterized by glycolysis, with a strong correlation to patient prognosis. Core transcription factors were pinpointed using hdWGCNA and metaVIPER. A specific transcription factor regulatory network was then constructed. A glycolysis-related prognostic model was developed and tested for estimating OC prognosis with a total of 85 machine-learning combinations, focusing on specific upregulated genes of two subtypes. We identified IGF2 as a key within the prognostic model and investigated its impact on OC progression and drug resistance through in vitro experiments, including the transwell assay, lactate production detection, and the CCK-8 assay.

RESULTS

Analysis showed that the Malignant 7 subcluster was primarily related to glycolysis. Two OC molecular subtypes, CS1 and CS2, were identified with distinct clinical, biological, and microenvironmental traits. A prognostic model was built, and IGF2 emerged as a key gene linked to prognosis. Experiments have proven that IGF2 can promote the glycolysis pathway and the malignant biological progression of OC cells.

CONCLUSIONS

We developed two novel OC subtypes based on glycolysis score, established a stable prognostic model, and identified IGF2 as the marker gene. These insights provided a new avenue for exploring OC's molecular mechanisms and personalized treatment approaches.

Identification of subgroups and development of prognostic risk models along the glycolysis-cholesterol synthesis axis in lung adenocarcinoma

Lung cancer is one of the most dangerous malignant tumors affecting human health. Lung adenocarcinoma (LUAD) is the most common subtype of lung cancer. Both glycolytic and cholesterogenic pathways play critical roles in metabolic adaptation to cancer. A dataset of 585 LUAD samples was downloaded from The Cancer Genome Atlas database. We obtained co-expressed glycolysis and cholesterogenesis genes by selecting and clustering genes from Molecular Signatures Database v7.5. We compared the prognosis of different subtypes and identified differentially expressed genes between subtypes. Predictive outcome events were modeled using machine learning, and the top 9 most important prognostic genes were selected by Shapley additive explanation analysis. A risk score model was built based on multivariate Cox analysis. LUAD patients were categorized into four metabolic subgroups: cholesterogenic, glycolytic, quiescent, and mixed. The worst prognosis was the mixed subtype. The prognostic model had great predictive performance in the test set. Patients with LUAD were effectively typed by glycolytic and cholesterogenic genes and were identified as having the worst prognosis in the glycolytic and cholesterogenic enriched gene groups. The prognostic model can provide an essential basis for clinicians to predict clinical outcomes for patients. The model was robust on the training and test datasets and had a great predictive performance.

Lactate-induced IGF1R protein lactylation promotes proliferation and metabolic reprogramming of lung cancer cells

Lung cancer (LC) is regarded as a fatal cancer, and insulin-like growth factor 1 (IGF1) and its receptor (IGF1R) have been found to play a key role in regulating tumor glycolytic metabolism. The aim of this study is to investigate LC proliferation regulated by metabolite-mediated IGF1R lactylation. IGF1R was highly expressed in LC tissues and cells, and the effects of IGF1R on protein stability were inhibited by Lactate dehydrogenase A (LDHA) inhibition. Moreover, the tightness of IGF1R binding to IGF1 was also enhanced by exogenous lactic acid but suppressed by LDHA silencing, while cell viability and proliferation were promoted by over-expression of IGF1R. Exogenous lactic acid further exacerbated the effects of the IGF1R gene, while LDHA knocking down reduced the IGF1R-induced malignant behaviors. The IGF1R and exogenous lactic acid were also found to increase extracellular acidification rate (ECAR) and decrease oxygen consumption rate to regulate glycolysis, which was inhibited by LDHA deficiency in LC cells. The study concluded that IGF1R-mediated aggressive behaviors of LC cells were associated with higher levels of IGF1R lactylation. Moreover, lactic acid can improve the protein stability of the IGF1R oncogene, thus promoting glycolysis and generating lactic acid, forming a closed loop. Therefore, targeting IGF1R is envisaged to provide a novel strategy for developing therapeutic agents against LC.

Preclinical Evaluation of JAB-2485, a Potent AURKA Inhibitor with High Selectivity and Favorable Pharmacokinetic Properties

As a critical mitotic regulator, Aurora kinase A (AURKA) is aberrantly activated in a wide range of cancers. Therapeutic targeting of AUKRA is a promising strategy for the treatment of solid tumors. In this study, we evaluated the preclinical characteristics of JAB-2485, a small-molecule inhibitor of AURKA currently in Phase I/IIa clinical trial in the US (NCT05490472). Biochemical studies demonstrated that JAB-2485 is potent and highly selective on AURKA, with subnanomolar IC50 and around 1500-fold selectivity over AURKB or AURKC. In addition, JAB-2485 exhibited favorable pharmacokinetic properties featured by low clearance and good bioavailability, strong dose-response relationship, as well as low risk for hematotoxicity and off-target liability. As a single agent, JAB-2485 effectively induced G2/M cell cycle arrest and apoptosis and inhibited the proliferation of small cell lung cancer, triple-negative breast cancer, and neuroblastoma cells. Furthermore, JAB-2485 exhibited robust in vivo antitumor activity both as monotherapy and in combination with chemotherapies or the bromodomain inhibitor JAB-8263 in xenograft models of various cancer types. Together, these encouraging preclinical data provide a strong basis for safety and efficacy evaluations of JAB-2485 in the clinical setting.

ARID1A loss induces P4HB to activate fibroblasts to support lung cancer cell growth, invasion, and chemoresistance

Loss of AT-interacting domain-rich protein 1A (ARID1A) frequently occurs in human malignancies including lung cancer. The biological consequence of ARID1A mutation in lung cancer is not fully understood. This study was designed to determine the effect of ARID1A-depleted lung cancer cells on fibroblast activation. Conditioned media was collected from ARID1A-depleted lung cancer cells and employed to treat lung fibroblasts. The proliferation and migration of lung fibroblasts were investigated. The secretory genes were profiled in lung cancer cells upon ARID1A knockdown. Antibody-based neutralization was utilized to confirm their role in mediating the cross-talk between lung cancer cells and fibroblasts. NOD-SCID-IL2RgammaC-null (NSG) mice received tumor tissues from patients with ARID1A-mutated lung cancer to establish patient-derived xenograft (PDX) models. Notably, ARID1A-depleted lung cancer cells promoted the proliferation and migration of lung fibroblasts. Mechanistically, ARID1A depletion augmented the expression and secretion of prolyl 4-hydroxylase beta (P4HB) in lung cancer cells, which induced the activation of lung fibroblasts through the β-catenin signaling pathway. P4HB-activated lung fibroblasts promoted the proliferation, invasion, and chemoresistance in lung cancer cells. Neutralizing P4HB hampered the tumor growth and increased cisplatin cytotoxic efficacy in two PDX models. Serum P4HB levels were higher in ARID1A-mutated lung cancer patients than in healthy controls. Moreover, increased serum levels of P4HB were significantly associated with lung cancer metastasis. Together, our work indicates a pivotal role for P4HB in orchestrating the cross-talk between ARID1A-mutated cancer cells and cancer-associated fibroblasts during lung cancer progression. P4HB may represent a promising target for improving lung cancer treatment.

ARID1A deficiency promotes progression and potentiates therapeutic antitumour immunity in hepatitis B virus-related hepatocellular carcinoma

BACKGROUND

Exploring predictive biomarkers and therapeutic strategies of ICBs has become an urgent need in clinical practice. Increasing evidence has shown that ARID1A deficiency might play a critical role in sculpting tumor environments in various tumors and might be used as pan-cancer biomarkers for immunotherapy outcomes. The current study aims to explored the immune-modulating role of ARID1A deficiency in Hepatitis B virus (HBV) related hepatocellular carcinoma (HBV-HCC) and its potential immunotherapeutic implications.

METHODS

In the current study, we performed a comprehensive analysis using bioinformatics approaches and pre-clinical experiments to evaluate the ARID1A regulatory role on the biological behavior, and immune landscape of Hepatitis B virus (HBV) related hepatocellular carcinoma (HBV-HCC). A total of 425 HBV-related hepatocellular carcinoma patients from TCGA-LIHC, AMC and CHCC-HBV cohort were enrolled in bioinformatics analysis. Immunohistochemical staining of HBV-HCC specimens and ARID1A deficiency cellular models were used to validate the results of the analysis.

RESULTS

Our results have shown that ARID1A deficiency promoted tumor proliferation and metastasis. More importantly, ARID1A deficiency in HBV-HCC was associated with the higher TMB, elevated immune activity, and up-regulated expression of immune checkpoint proteins, especially TIM-3 in HBV-HCC. Further, the expression of Galectin-9, which is the ligand of TIM-3, was elevated in the ARID1A knockout HBV positive cell line.

CONCLUSION

To conclude, we have shown that the ARID1A deficiency was correlated with more active immune signatures and higher expression of immune checkpoints in HBV-HCC. Additionally, the present study provides insights to explore the possibility of the predictive role of ARID1A in HBV-HCC patients responsive to immunotherapy.

Amplifying "eat me signal" by immunogenic cell death for potentiating cancer immunotherapy

Immunogenic cell death (ICD) is a unique mode of cell death, which can release immunogenic damage-associated molecular patterns (DAMPs) and tumor-associated antigens to trigger long-term protective antitumor immune responses. Thus, amplifying "eat me signal" during tumor ICD cascade is critical for cancer immunotherapy. Some therapies (radiotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), etc.) and inducers (chemotherapeutic agents, etc.) have enabled to initiate and/or facilitate ICD and activate antitumor immune responses. Recently, nanostructure-based drug delivery systems have been synthesized for inducing ICD through combining treatment of chemotherapeutic agents, photosensitizers for PDT, photothermal transformation agents for PTT, radiosensitizers for radiotherapy, etc., which can release loaded agents at an appropriate dosage in the designated place at the appropriate time, contributing to higher efficiency and lower toxicity. Also, immunotherapeutic agents in combination with nanostructure-based drug delivery systems can produce synergetic antitumor effects, thus potentiating immunotherapy. Overall, our review outlines the emerging ICD inducers, and nanostructure drug delivery systems loading diverse agents to evoke ICD through chemoradiotherapy, PDT, and PTT or combining immunotherapeutic agents. Moreover, we discuss the prospects and challenges of harnessing ICD induction-based immunotherapy, and highlight the significance of multidisciplinary and interprofessional collaboration to promote the optimal translation of this treatment strategy.

The Role of the AT-Rich Interaction Domain 1A Gene (ARID1A) in Human Carcinogenesis

The switch/sucrose non-fermentable (SWI/SNF) (SWI/SNF) complex uses energy from ATP hydrolysis to mobilise nucleosomes on chromatin. Components of SWI/SNF are mutated in 20% of all human cancers, of which mutations in AT-rich binding domain protein 1A (ARID1A) are the most common. ARID1A is mutated in nearly half of ovarian clear cell carcinoma and around one-third of endometrial and ovarian carcinomas of the endometrioid type. This review will examine in detail the molecular functions of ARID1A, including its role in cell cycle control, enhancer regulation, and the prevention of telomerase activity. ARID1A has key roles in the maintenance of genomic integrity, including DNA double-stranded break repair, DNA decatenation, integrity of the cohesin complex, and reduction in replication stress, and is also involved in mismatch repair. The role of ARID1A loss in the pathogenesis of some of the most common human cancers is discussed, with a particular emphasis on gynaecological cancers. Finally, several promising synthetic lethal strategies, which exploit the specific vulnerabilities of ARID1A-deficient cancer cells, are briefly mentioned.

Identification and characterization of ARID1A-interacting proteins in renal tubular cells and their molecular regulation of angiogenesis

BACKGROUND

Defects and deficiency of AT-rich interactive domain-containing protein 1A (ARID1A) encoded by a tumor suppressor gene ARID1A have recently been suggested to get involved in angiogenesis, a crucial process in carcinogenesis. However, molecular mechanisms of ARID1A deficiency to induce angiogenesis in kidney cancer remain underinvestigated.

METHODS

We performed large-scale identification of ARID1A protein interactors in renal tubular epithelial cells (RTECs) using immunoprecipitation (IP) followed by nanoLC-ESI-LTQ-Orbitrap tandem mass spectrometry (MS/MS). Their roles in angiogenesis were investigated using various assays.

RESULTS

A total of 74 ARID1A-interacting proteins were identified. Protein-protein interactions analysis revealed that these identified proteins interacted directly or indirectly with ARID1A. Among them, the direct interaction between ARID1A and β-actin was validated by IP and reciprocal IP followed by Western blotting. Small interfering RNA (siRNA) was used for single and double knockdowns of ARID1A and ACTB. Semi-quantitative RT-PCR demonstrated that deficiency of ARID1A, but not ACTB, significantly affected expression of angiogenesis-related genes in RTECs (VEGF and FGF2 were increased, whereas PDGF and EGF were decreased). However, the knockdowns did not affect TGFB1 and FGF1 levels. The quantitative mRNA expression data of VEGF and TGFB1 were consistent with the secreted levels of their protein products as measured by ELISA. Only secreted products derived from ARID1A-deficient RTECs significantly increased endothelial cells (ECs) migration and tube formation. Some of the other carcinogenic features could also be confirmed in the ARID1A-deficient RTECs, including increased cell migration and chemoresistance. Double knockdowns of both ARID1A and ACTB did not enhance the effects of single ARID1A knockdown in all assays.

CONCLUSIONS

We report herein a large dataset of the ARID1A-interacting proteins in RTECs using an IP-MS/MS approach and confirm the direct interaction between ARID1A and β-actin. However, the role of ARID1A deficiency in angiogenesis is independent of β-actin.

Gene-network analysis predicts clinical response to immunotherapy in patients affected by NSCLC

OBJECTIVES

Predictive biomarkers of response to immune checkpoint inhibitors (ICIs) have been extensively studied in non-small cell lung cancer (NSCLC) with controversial results. Recently, gene-network analysis emerged as a new tool to address tumor biology and behavior, representing a potential tool to evaluate response to therapies.

METHODS

Clinical data and genetic profiles of 644 advanced NSCLCs were retrieved from cBioPortal and the Cancer Genome Atlas (TCGA); 243 ICI-treated NSCLCs were used to identify an immunotherapy response signatures via mutated gene network analysis and K-means unsupervised clustering. Signatures predictive values were tested in an external dataset of 242 cases and assessed versus a control group of 159 NSCLCs treated with standard chemotherapy.

RESULTS

At least two mutations in the coding sequence of genes belonging to the chromatin remodelling pathway (A signature), and/or at least two mutations of genes involved in cell-to-cell signalling pathways (B signature), showed positive prediction in ICI-treated advanced NSCLC. Signatures performed best when combined for patients undergoing first-line immunotherapy, and for those receiving combined ICIs.

CONCLUSIONS

Alterations in genes related to chromatin remodelling complexes and cell-to-cell crosstalk may force dysfunctional immune evasion, explaining susceptibility to immunotherapy. Therefore, exploring mutated gene networks could be valuable for determining essential biological interactions, contributing to treatment personalization.

Low level of ARID1A contributes to adaptive immune resistance and sensitizes triple-negative breast cancer to immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) shed new light on triple-negative breast cancer (TNBC), but only a minority of patients demonstrate response. Therefore, adaptive immune resistance (AIR) needs to be further defined to guide the development of ICI regimens.

METHODS

Databases, including The Cancer Genome Atlas, Gene Ontology Resource, University of California Santa Cruz Genome Browser, and Pubmed, were used to screen epigenetic modulators, regulators for CD8+ T cells, and transcriptional regulators of programmed cell death-ligand 1 (PD-L1). Human peripheral blood mononuclear cell (Hu-PBMC) reconstruction mice were adopted for xenograft transplantation. Tumor specimens from a TNBC cohort and the clinical trial CTR20191353 were retrospectively analyzed. RNA-sequencing, Western blotting, qPCR and immunohistochemistry were used to assess gene expression. Coculture assays were performed to evaluate the regulation of TNBC cells on T cells. Chromatin immunoprecipitation and transposase-accessible chromatin sequencing were used to determine chromatin-binding and accessibility.

RESULTS

The epigenetic modulator AT-rich interaction domain 1A (ARID1A) gene demonstrated the highest expression association with AIR relative to other epigenetic modulators in TNBC patients. Low ARID1A expression in TNBC, causing an immunosuppressive microenvironment, promoted AIR and inhibited CD8+ T cell infiltration and activity through upregulating PD-L1. However, ARID1A did not directly regulate PD-L1 expression. We found that ARID1A directly bound the promoter of nucleophosmin 1 (NPM1) and that low ARID1A expression increased NPM1 chromatin accessibility as well as gene expression, further activating PD-L1 transcription. In Hu-PBMC mice, atezolizumab demonstrated the potential to reverse ARID1A deficiency-induced AIR in TNBC by reducing tumor malignancy and activating anti-tumor immunity. In CTR20191353, ARID1A-low patients derived more benefit from pucotenlimab compared to ARID1A-high patients.

CONCLUSIONS

In AIR epigenetics, low ARID1A expression in TNBC contributed to AIR via the ARID1A/NPM1/PD-L1 axis, leading to poor outcome but sensitivity to ICI treatment.

ARID1A mutations in lung cancer: biology, prognostic role, and therapeutic implications

Mutations in the AT-interacting domain-rich protein 1A (ARID1A) gene, a critical component of the switch/sucrose nonfermentable (SWI/SNF) complex, are frequently found in most human cancers. Approximately 5-10% of lung cancers carry ARID1A mutations. ARID1A loss in lung cancer correlates with clinicopathological features and poor prognosis. Co-mutation of ARID1A and epidermal growth factor receptor (EGFR) results in the limited efficacy of EGFR tyrosine kinase inhibitors (EGFR-TKIs) but increases the clinical benefit of immune checkpoint inhibitors (ICIs). ARID1A gene mutation plays a role in cell cycle regulation, metabolic reprogramming, and epithelial-mesenchymal transition. We present the first comprehensive review of the relationship between ARID1A gene mutations and lung cancer and discuss the potential of ARID1A as a new molecular target.

Recent insights into the SWI/SNF complex and the molecular mechanism of hSNF5 deficiency in rhabdoid tumors

Genetic information encoded by DNA is packaged in the nucleus using the chromatin structure. The accessibility of transcriptional elements in DNA is controlled by the dynamic structural changes of chromatin for the appropriate regulation of gene transcription. Chromatin structure is regulated by two general mechanisms, one is histone modification and the other is chromatin remodeling in an ATP-dependent manner. Switch/sucrose nonfermentable (SWI/SNF) complexes utilize the energy from ATP hydrolysis to mobilize nucleosomes and remodel the chromatin structure, contributing to conformational changes in chromatin. Recently, the inactivation of encoding genes for subunits of the SWI/SNF complexes has been documented in a series of human cancers, accounting for up to almost 20% of all human cancers. For example, human SNF5 (hSNF5), the gene that encodes a subunit of the SWI/SNF complexes, is the sole mutation target that drives malignant rhabdoid tumors (MRT). Despite remarkably simple genomes, the MRT has highly malignant characteristics. As a key to understanding MRT tumorigenesis, it is necessary to fully examine the mechanism of chromatin remodeling by the SWI/SNF complexes. Herein, we review the current understanding of chromatin remodeling by focusing on SWI/SNF complexes. In addition, we describe the molecular mechanisms and influences of hSNF5 deficiency in rhabdoid tumors and the prospects for developing new therapeutic targets to overcome the epigenetic drive of cancer that is caused by abnormal chromatin remodeling.

ARID1A Inactivation Increases Expression of circ0008399 and Promotes Cisplatin Resistance in Bladder Cancer

OBJECTIVE

Cisplatin (CDDP)-based chemotherapy is a first-line, drug regimen for muscle-invasive bladder cancer (BC) and metastatic bladder cancer. Clinically, resistance to CDDP restricts the clinical benefit of some bladder cancer patients. AT-rich interaction domain 1A (ARID1A) gene mutation occurs frequently in bladder cancer; however, the role of CDDP sensitivity in BC has not been studied.

METHODS

We established ARID1A knockout BC cell lines using CRISPR/Cas9 technology. IC50 determination, flow cytometry analysis of apoptosis, and tumor xenograft assays were performed to verify changes in the CDDP sensitivity of BC cells losing ARID1A. qRT-PCR, Western blotting, RNA interference, bioinformatic analysis, and ChIP-qPCR analysis were performed to further explore the potential mechanism of ARID1A inactivation in CDDP sensitivity in BC.

RESULTS

It was found that ARID1A inactivation was associated with CDDP resistance in BC cells. Mechanically, loss of ARID1A promoted the expression of eukaryotic translation initiation factor 4A3 (EIF4A3) through epigenetic regulation. Increased expression of EIF4A3 promoted the expression of hsa_circ_0008399 (circ0008399), a novel circular RNA (circRNA) identified in our previous study, which, to some extent, showed that ARID1A deletion caused CDDP resistance through the inhibitory effect of circ0008399 on the apoptosis of BC cells. Importantly, EIF4A3-IN-2 specifically inhibited the activity of EIF4A3 to reduce circ0008399 production and restored the sensitivity of ARID1A inactivated BC cells to CDDP.

CONCLUSION

Our research deepens the understanding of the mechanisms of CDDP resistance in BC and elucidates a potential strategy to improve the efficacy of CDDP in BC patients with ARID1A deletion through combination therapy targeting EIF4A3.

Transcriptional-translational conflict is a barrier to cellular transformation and cancer progression

We uncover a tumor-suppressive process in urothelium called transcriptional-translational conflict caused by deregulation of the central chromatin remodeling component ARID1A. Loss of Arid1a triggers an increase in a nexus of pro-proliferation transcripts, but a simultaneous inhibition of the eukaryotic elongation factor 2 (eEF2), which results in tumor suppression. Resolution of this conflict through enhancing translation elongation speed enables the efficient and precise synthesis of a network of poised mRNAs resulting in uncontrolled proliferation, clonogenic growth, and bladder cancer progression. We observe a similar phenomenon in patients with ARID1A-low tumors, which also exhibit increased translation elongation activity through eEF2. These findings have important clinical implications because ARID1A-deficient, but not ARID1A-proficient, tumors are sensitive to pharmacologic inhibition of protein synthesis. These discoveries reveal an oncogenic stress created by transcriptional-translational conflict and provide a unified gene expression model that unveils the importance of the crosstalk between transcription and translation in promoting cancer.

The Role of Genetic Mutations in Mitochondrial-Driven Cancer Growth in Selected Tumors: Breast and Gynecological Malignancies

There is an increasing understanding of the molecular and cytogenetic background of various tumors that helps us better conceptualize the pathogenesis of specific diseases. Additionally, in many cases, these molecular and cytogenetic alterations have diagnostic, prognostic, and/or therapeutic applications that are heavily used in clinical practice. Given that there is always room for improvement in cancer treatments and in cancer patient management, it is important to discover new therapeutic targets for affected individuals. In this review, we discuss mitochondrial changes in breast and gynecological (endometrial and ovarian) cancers. In addition, we review how the frequently altered genes in these diseases (BRCA1/2, HER2, PTEN, PIK3CA, CTNNB1, RAS, CTNNB1, FGFR, TP53, ARID1A, and TERT) affect the mitochondria, highlighting the possible associated individual therapeutic targets. With this approach, drugs targeting mitochondrial glucose or fatty acid metabolism, reactive oxygen species production, mitochondrial biogenesis, mtDNA transcription, mitophagy, or cell death pathways could provide further tailored treatment.

Targeting ARID1A-Deficient Cancers: An Immune-Metabolic Perspective

Epigenetic remodeling and metabolic reprogramming, two well-known cancer hallmarks, are highly intertwined. In addition to their abilities to confer cancer cell growth advantage, these alterations play a critical role in dynamically shaping the tumor microenvironment and antitumor immunity. Recent studies point toward the interplay between epigenetic regulation and metabolic rewiring as a potentially targetable Achilles' heel in cancer. In this review, we explore the key metabolic mechanisms that underpin the immunomodulatory role of AT-rich interaction domain 1A (ARID1A), the most frequently mutated epigenetic regulator across human cancers. We will summarize the recent advances in targeting ARID1A-deficient cancers by harnessing immune-metabolic vulnerability elicited by ARID1A deficiency to stimulate antitumor immune response, and ultimately, to improve patient outcome.

Establishing a prognostic model of chromatin modulators and identifying potential drug candidates in renal clear cell patients

BACKGROUND

Renal carcinoma is a common malignant tumor of the urinary system. Advanced renal carcinoma has a low 5-year survival rate and a poor prognosis. More and more studies have confirmed that chromatin regulators (CRs) can regulate the occurrence and development of cancer. This article investigates the functional and prognostic value of CRs in renal carcinoma patients.

METHODS

mRNA expression and clinical information were obtained from The Cancer Genome Atlas database. Univariate Cox regression analysis and LASSO regression analysis were used to select prognostic chromatin-regulated genes and use them to construct a risk model for predicting the prognosis of renal cancer. Differences in prognosis between high-risk and low-risk groups were compared using Kaplan-Meier analysis. In addition, we analyzed the relationship between chromatin regulators and tumor immune infiltration, and explored differences in drug sensitivity between risk groups.

RESULTS

We constructed a model consisting of 11 CRs to predict the prognosis of renal cancer patients. We not only successfully validated its feasibility, but also found that the 11 CR-based model was an independent prognostic factor. Functional analysis showed that CRs were mainly enriched in cancer development-related signalling pathways. We also found through the TIMER database that CR-based models were also associated with immune cell infiltration and immune checkpoints. At the same time, the genomics of drug sensitivity in cancer database was used to analyze the commonly used drugs of renal clear cell carcinoma patients. It was found that patients in the low-risk group were sensitive to medicines such as axitinib, pazopanib, sorafenib, and gemcitabine. In contrast, those in the high-risk group may be sensitive to sunitinib.

CONCLUSION

The chromatin regulator-related prognostic model we constructed can be used to assess the prognostic risk of patients with clear cell renal cell carcinoma. The results of this study can bring new ideas for targeted therapy of clear cell renal carcinoma, helping doctors to take corresponding measures in advance for patients with different risks.

Hypoxic microenvironment in cancer: molecular mechanisms and therapeutic interventions

Having a hypoxic microenvironment is a common and salient feature of most solid tumors. Hypoxia has a profound effect on the biological behavior and malignant phenotype of cancer cells, mediates the effects of cancer chemotherapy, radiotherapy, and immunotherapy through complex mechanisms, and is closely associated with poor prognosis in various cancer patients. Accumulating studies have demonstrated that through normalization of the tumor vasculature, nanoparticle carriers and biocarriers can effectively increase the oxygen concentration in the tumor microenvironment, improve drug delivery and the efficacy of radiotherapy. They also increase infiltration of innate and adaptive anti-tumor immune cells to enhance the efficacy of immunotherapy. Furthermore, drugs targeting key genes associated with hypoxia, including hypoxia tracers, hypoxia-activated prodrugs, and drugs targeting hypoxia-inducible factors and downstream targets, can be used for visualization and quantitative analysis of tumor hypoxia and antitumor activity. However, the relationship between hypoxia and cancer is an area of research that requires further exploration. Here, we investigated the potential factors in the development of hypoxia in cancer, changes in signaling pathways that occur in cancer cells to adapt to hypoxic environments, the mechanisms of hypoxia-induced cancer immune tolerance, chemotherapeutic tolerance, and enhanced radiation tolerance, as well as the insights and applications of hypoxia in cancer therapy.

ARID1A loss in pancreas leads to islet developmental defect and metabolic disturbance

ARID1A is a tumor suppressor gene mutated in 7-10% of pancreatic cancer patients. However, its function in pancreas development and endocrine regulation is unclear. We generated mice that lack Arid1a expression in the pancreas. Our results showed that deletion of the Arid1a gene in mice caused a reduction in islet numbers and insulin production, both of which are associated with diabetes mellitus (DM) phenotype. RNA sequencing of isolated islets confirmed DM gene signature and decrease of developmental lineage genes. We identified neurogenin3, a transcription factor that controls endocrine fate specification, is a direct target of Aird1a. Gene set enrichment analysis indicated the enhancement of histone deacetylase (HDAC) pathway after Arid1a depletion and a clinically approved HDAC inhibitor showed therapeutic benefit by suppressing disease onset. Our data suggest that Arid1a is required for the development of pancreatic islets by regulating Ngn3+-mediated transcriptional program and is important in maintaining endocrine function.

Targeting sphingosine kinase 1/2 by a novel dual inhibitor SKI-349 suppresses non-small cell lung cancer cell growth

Sphingosine kinase 1 (SphK1) and sphingosine kinase (SphK2) are both important therapeutic targets of non-small cell lung cancer (NSCLC). SKI-349 is a novel, highly efficient and small molecular SphK1/2 dual inhibitor. Here in primary human NSCLC cells and immortalized cell lines, SKI-349 potently inhibited cell proliferation, cell cycle progression, migration and viability. The dual inhibitor induced mitochondrial depolarization and apoptosis activation in NSCLC cells, but it was non-cytotoxic to human lung epithelial cells. SKI-349 inhibited SphK activity and induced ceramide accumulation in primary NSCLC cells, without affecting SphK1/2 expression. SKI-349-induced NSCLC cell death was attenuated by sphingosine-1-phosphate and by the SphK activator K6PC-5, but was potentiated by the short-chain ceramide C6. Moreover, SKI-349 induced Akt-mTOR inactivation, JNK activation, and oxidative injury in primary NSCLC cells. In addition, SKI-349 decreased bromodomain-containing protein 4 (BRD4) expression and downregulated BRD4-dependent genes (Myc, cyclin D1 and Klf4) in primary NSCLC cells. At last, SKI-349 (10 mg/kg) administration inhibited NSCLC xenograft growth in nude mice. Akt-mTOR inhibition, JNK activation, oxidative injury and BRD4 downregulation were detected in SKI-349-treated NSCLC xenograft tissues. Taken together, targeting SphK1/2 by SKI-349 potently inhibits NSCLC cell growth in vitro and in vivo.