NFATc3 mediates the sensitivity of gastric cancer cells to arsenic sulfide

Pharmacology, Toxicology, and Rational Application of Cinnabar, Realgar, and Their Formulations

Ethnopharmacological Relevance. Mineral medicines are widely used traditional Chinese medicines with curative effects. These medicines are used for many refractory diseases. Aim of the Review. In this review, cinnabar (HgS) and realgar (As₂S₂) serve as examples of mineral medicines, and their pharmacology, therapeutic toxicity, use in traditional medicine mixtures, and research perspectives are discussed. Materials and Methods. A search was performed for the literature on cinnabar and realgar in PubMed, the Chinese Pharmacopeia, Google, and other sources. The search included studies using single herbs, traditional formulations, or novel dosage forms. Results. Cinnabar and cinnabar formulas exhibit good efficacy for sedation, sleep improvement, anxiety alleviation, and brain protection. However, previous studies on neurotransmitters have reached different conclusions, and detailed pharmacological mechanisms are lacking. Realgar and its formulas exert promising antitumor activity through regulation of cell cycle arrest, intrinsic and extrinsic apoptosis, induction of differentiation, autophagy, metabolic reprogramming, matrix metalloproteinase-9 (MMP-9) signaling, and reactive oxygen species (ROS) generation. In addition, realgar can be used to treat a variety of refractory diseases by regulating immunity and exerting antibacterial, antiviral, and other effects. However, the existing pharmacological research on the use of realgar for epidemic prevention is insufficient, and animal experiments and research at the cellular level are lacking. Inappropriate applications of cinnabar and realgar can cause toxicity, including neurotoxicity, liver toxicity, kidney toxicity, and genotoxicity. The toxicological mechanism is complex, and molecular-level research is limited. For clinical applications, theory and clinical experience must be combined to guide scientific and rational drug use and to achieve reduced toxicity and increased efficacy through the use of modern preparation methods or combined drugs. Notably, when cinnabar and realgar are used to treat targeted diseases, these agents have a bidirectional effect of “treatment” and “toxicity” on the central nervous system in pathological and normal states. The pharmacological and toxicological mechanisms need to be elucidated in greater detail in the future. Overall, systematic research is needed to provide a basis for better promotion of the rational use of cinnabar and realgar in the clinic. Conclusion. Mineral medicines are multicomponent, multiactivity, and multitargeted substances. The pharmacology and mechanisms of the toxicity and action of realgar and cinnabar are extremely complex. A number of Chinese medicinal preparations of realgar and cinnabar have demonstrated unique efficacy in the treatment of refractory diseases.

Obesity-Associated Differentially Methylated Regions in Colon Cancer

Obesity with adiposity is a common disorder in modern days, influenced by environmental factors such as eating and lifestyle habits and affecting the epigenetics of adipose-based gene regulations and metabolic pathways in colorectal cancer (CRC). We compared epigenetic changes of differentially methylated regions (DMR) of genes in colon tissues of 225 colon cancer cases (154 non-obese and 71 obese) and 15 healthy non-obese controls by accessing The Cancer Genome Atlas (TCGA) data. We applied machine-learning-based analytics including generalized regression (GR) as a confirmatory validation model to identify the factors that could contribute to DMRs impacting colon cancer to enhance prediction accuracy. We found that age was a significant predictor in obese cancer patients, both alone (p = 0.003) and interacting with hypomethylated DMRs of ZBTB46, a tumor suppressor gene (p = 0.008). DMRs of three additional genes: HIST1H3I (p = 0.001), an oncogene with a hypomethylated DMR in the promoter region; SRGAP2C (p = 0.006), a tumor suppressor gene with a hypermethylated DMR in the promoter region; and NFATC4 (p = 0.006), an adipocyte differentiating oncogene with a hypermethylated DMR in an intron region, are also significant predictors of cancer in obese patients, independent of age. The genes affected by these DMR could be potential novel biomarkers of colon cancer in obese patients for cancer prevention and progression.

Mineral medicine: from traditional drugs to multifunctional delivery systems

Mineral drugs are an important constituent of traditional Chinese medicine (TCM). Taking minerals that contain heavy metals as drugs is a very national characteristic part of TCM. However, the safety and scientific nature of mineral drugs are controversial owing to their heavy metals and strong toxicity. In 2000, the Food and Drug Administration (FDA) authorized arsenic trioxide (ATO) as first-line therapy for acute promyelocytic leukemia. This makes the development and utilization of mineral drugs become a research hotspot. The development of nanomedicine has found a great prospect of mineral drugs in nano-delivery carriers. And that will hold promise to address the numerous biological barriers facing mineral drug formulations. However, the studies on mineral drugs in the delivery system are few at present. There is also a lack of a detailed description of mineral drug delivery systems. In this review, the advanced strategies of mineral drug delivery systems in tumor therapy are summarized. In addition, the therapeutic advantages and research progress of novel mineral drug delivery systems are also discussed. Here, we hope that this will provide a useful reference for the design and application of new mineral drug delivery systems.

Arsenic sulfide inhibits the progression of gastric cancer through regulating the circRNA_ASAP2/Wnt/β-catenin pathway

In our paper, the effects of As4S4 treatments on the growth and migration of gastric cancer (GC) cells were explored, and the potential underlying molecular mechanisms were also identified. Cell viability was evaluated by cell counting kit 8 assay. The expression of Ki-67 was examined using immunofluorescence staining. Cell apoptosis was assessed by flow cytometry. The migratory and invasion abilities of cells were determined using Transwell assay. The mRNA and protein levels of related gene were examined by RT-qPCR and western blotting, respectively. CircRNAs chip was performed to identify the differentiated expression of circRNAs in GC cells following the treatment with As4S4. Our results revealed that the proliferation, migration and invasion of GC cells were remarkably suppressed by the treatment with As4S4, while cell apoptosis was promoted. Furthermore, circRNA_ASAP2 was a novel target of As4S4 in GC, and it is involved in As4S4-modulated biological behavior alterations in GC cells. In addition, the activities of the Wnt/β-catenin signaling in GC cells were affected by the overexpression circRNA_ASAP2 and the treatment with As4S4. Moreover, the behavior changes in GC cells caused by the knockdown of circRNA_ASAP2 were reversed by the treatment with Wnt agonist SKL2001. In summary, As4S4 could function as an antitumor agent in GC through regulating the circRNA_ASAP2/Wnt/β-catenin pathway, which in turn influences the growth and metastasis of GC cells.

TUGDA: task uncertainty guided domain adaptation for robust generalization of cancer drug response prediction from in vitro to in vivo settings

MOTIVATION

Large-scale cancer omics studies have highlighted the diversity of patient molecular profiles and the importance of leveraging this information to deliver the right drug to the right patient at the right time. Key challenges in learning predictive models for this include the high-dimensionality of omics data and heterogeneity in biological and clinical factors affecting patient response. The use of multi-task learning techniques has been widely explored to address dataset limitations for in vitro drug response models, while domain adaptation (DA) has been employed to extend them to predict in vivo response. In both of these transfer learning settings, noisy data for some tasks (or domains) can substantially reduce the performance for others compared to single-task (domain) learners, i.e. lead to negative transfer (NT).

RESULTS

We describe a novel multi-task unsupervised DA method (TUGDA) that addresses these limitations in a unified framework by quantifying uncertainty in predictors and weighting their influence on shared feature representations. TUGDA's ability to rely more on predictors with low-uncertainty allowed it to notably reduce cases of NT for in vitro models (94% overall) compared to state-of-the-art methods. For DA to in vivo settings, TUGDA improved over previous methods for patient-derived xenografts (9 out of 14 drugs) as well as patient datasets (significant associations in 9 out of 22 drugs). TUGDA's ability to avoid NT thus provides a key capability as we try to integrate diverse drug-response datasets to build consistent predictive models with in vivo utility.

AVAILABILITYAND IMPLEMENTATION

https://github.com/CSB5/TUGDA.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

TRPC3 promotes tumorigenesis of gastric cancer via the CNB2/GSK3β/NFATc2 signaling pathway

The transient receptor potential canonical (TRPC) channels have been implicated in various types of malignancies including gastric cancer (GC). However, the detailed mechanisms of TRPC channels underlying cell proliferation and apoptosis of GC cells remain largely unknown. Here, we report that TRPC3 was highly expressed in clinical GC specimens and correlated with GC malignant progression and poor prognosis. Forced expression of TRPC3 in GC cells enhanced both receptor-operated Ca²⁺ entry (ROCE) and store-operated Ca²⁺ entry (SOCE) and promoted the nuclear factor of activated T cell 2 (NFATc2) nuclear translocation by AKT/GSK-3β and CNB2 signaling. Pharmacological inhibition of TRPC3 or CRISPR/Cas9-mediated TRPC3 knockout effectively inhibited the growth of GC cells both in vitro and in vivo. These effects were reversible by the rescue of TRPC3 expression. Furthermore, we confirmed the role of TRPC3 and the ROCE-AKT/GSK3β-CNB2/NFATc2 signaling cascade in regulating cell cycle checkpoint, apoptosis cascade, and intracellular ROS production in GC. Overall, our findings suggest an oncogenic role of TRPC3 in GC and may highlight a potential target of TRPC3 for therapeutic intervention of GC and its malignant progression.

Expression, Prognosis and Gene Regulation Network of NFAT Transcription Factors in Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. The nuclear factor of activated T cells (NFAT) family is implicated in tumorigenesis and progression in various types of cancer. However, little is known about their expression patterns, distinct prognostic values, and potential regulatory networks in NSCLC. In this study, we comprehensively analyzed the distinct expression and prognostic value of NFATs in NSCLC through various large databases, including the Oncomine, UCSC Xena Browser, UALCAN databases, Kaplan–Meier Plotter, cBioPortal, and Enrichr. In lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), NFAT1/2/4/5 mRNA expression levels were significantly decreased and NFAT3 mRNA expression level was significantly increased. The cBioPortal database analysis showed that the mRNA dysregulation was one of the single most important factors for NFAT alteration in LUAD and LUSC and that both LUAD and LUSC cases with the alterations in the mRNA expression of NFATs had significantly better overall survival (OS). High expression levels of NFAT1/2/4/5 were significantly associated with better OS in LUAD, whereas high NFAT3 expression led to a worse OS. Overexpression of NFAT1/2 predicted better OS in LUSC, whereas high NFAT5 expression led to a worse OS. The networks for NFATs and the 50 most frequently altered neighbor genes in LUAD and LUSC were also constructed. NFATs and genes significantly associated with NFAT mRNA expression in LUAD and LUSC were significantly enriched in the cGMP-dependent protein kinase and Wnt signaling pathways. These results showed that the NFAT family members displayed varying degrees of abnormal expressions, suggesting that NFATs may be therapeutic targets for patients with NSCLC. Aberrant expression of NFATs was found to be associated with OS in the patients with NSCLC; among NFATs, NFAT3/4 may be new biomarkers for the prognosis of LUAD. However, further studies are required to validate our findings.

Effects of Selenium on Arsenic-Induced Liver Lesions in Broilers

The aim of the present study was to investigate the abilities of selenium to counteract the toxic damage of arsenic (As). Two hundred 1-day-old healthy male broilers were randomly divided into five groups and fed the following diets: control group (0.1 mg/kg As + 0.2 mg/kg Se), As group (3 mg/kg As + 0.2 mg/kg Se), As + Se group I (3 mg/kg As + 5 mg/kg Se), As + Se group II (3 mg/kg As + 10 mg/kg Se), and As + Se group III (3 mg/kg As + 15 mg/kg Se), respectively. The relative weight of the liver, hepatic protein content, GSH-Px levels, SOD activities, NO contents, iNOS and tNOS activities, and increased malondialdehyde contents, ALT and AST activities, and the apoptotic hepatocytes were analyzed. Adding 3 mg/kg arsenic to the diet caused the growth and development of chicken liver to be blocked, resulting in decrease of protein contents in liver tissue, decrease of SOD and GSH-Px activities, increase of MDA contents, decrease of NO contents, decrease of iNOS and TNOs activities, increase of ALT and AST activities, increase of apoptosis rates of liver cells. Compared to the 3-mg/kg arsenic group, adding 5 mg/kg and 10 mg/kg selenium, respectively, could repair the liver growth retardation and steatosis caused by arsenic, increase the protein contents in liver tissue, increase the activities of SOD and GSH-Px, reduce the contents of MDA, increase the contents of NO, enhance the activities of iNOS and TNOs, reduce the activities of ALT and AST, and reduce the rates of apoptosis of liver cells, in which the best effects are to add 10 mg/kg selenium. While 15 mg/kg of sodium selenite may induce progression of As-induced hepatic lesions, the results indicated that 5 and 10 mg/kg of sodium selenite supplied in the diet, through mechanisms of oxidative stress and apoptosis regulation, may ameliorate As-induced hepatic lesions in a dose-dependent manner.

As4S4 Exhibits Good Killing Effect on Multiple Myeloma Cells Via Repressing SOCS1 Methylation-Mediated JAK2/STAT3 Signaling Pathway

Objective:

This study aimed to investigate the effect of tetra-arsenic tetra-sulfide on treating multiple myeloma and its potential regulation on suppressor of cytokine signaling 1 methylation-mediated Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway.

Methods:

Tetra-arsenic tetra-sulfide with different concentrations were used to treat U266 cells, and cell viability was measured at 12, 24, and 48 hours with 0 μM tetra-arsenic tetra-sulfide treatment as control by Cell Counting Kit-8 assay. Suppressor of cytokine signaling 1 methylation and expression were determined by methylation-specific polymerase chain reaction, quantitative polymerase chain reaction, and Western blot, respectively, in U266 cells and normal plasma cells and in U266 cells treated by tetra-arsenic tetra-sulfide. Then, rescue experiments were performed by transfecting suppressor of cytokine signaling 1 small interfering RNA into tetra-arsenic tetra-sulfide-treated U266 cells. Besides, phosphor–Janus kinase 2, Janus kinase 2, phospho–signal transducer and activator of transcription 3, and signal transducer and activator of transcription 3 expressions were determined by Western blot.

Results:

Tetra-arsenic tetra-sulfide inhibited U266 cell viability efficiently in a dose- and time-dependent manner. Suppressor of cytokine signaling 1 methylation was higher while suppressor of cytokine signaling 1 expression was lower in U266 cells compared to normal plasma cells; when treated by tetra-arsenic tetra-sulfide, suppressor of cytokine signaling 1 methylation was decreased while suppressor of cytokine signaling 1 expression was increased in U266 cells, along with the reduced phospho–Janus kinase 2 and phospho–signal transducer and activator of transcription 3 expressions. Then, suppressor of cytokine signaling 1 small interfering RNA enhanced the cell viability and phospho–Janus kinase 2 as well as phospho–signal transducer and activator of transcription 3 expressions in both tetra-arsenic tetra-sulfide treatment-free and tetra-arsenic tetra-sulfide-treated U266 cells.

Conclusion:

Tetra-arsenic tetra-sulfide exhibits good killing effect on multiple myeloma cells via repressing suppressor of cytokine signaling 1 methylation and downstream Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway, which might serve as a potential treatment option for multiple myeloma.

NFATC4 promotes quiescence and chemotherapy resistance in ovarian cancer

Development of chemotherapy resistance is a major problem in ovarian cancer. One understudied mechanism of chemoresistance is the induction of quiescence, a reversible nonproliferative state. Unfortunately, little is known about regulators of quiescence. Here, we identify the master transcription factor nuclear factor of activated T cells cytoplasmic 4 (NFATC4) as a regulator of quiescence in ovarian cancer. NFATC4 is enriched in ovarian cancer stem-like cells and correlates with decreased proliferation and poor prognosis. Treatment of cancer cells with cisplatin resulted in NFATC4 nuclear translocation and activation of the NFATC4 pathway, while inhibition of the pathway increased chemotherapy response. Induction of NFATC4 activity resulted in a marked decrease in proliferation, G0 cell cycle arrest, and chemotherapy resistance, both in vitro and in vivo. Finally, NFATC4 drove a quiescent phenotype in part via downregulation of MYC. Together, these data identify NFATC4 as a driver of quiescence and a potential new target to combat chemoresistance in ovarian cancer.

Arsenic sulfide induces RAG1-dependent DNA damage for cell killing by inhibiting NFATc3 in gastric cancer cells

Background

Arsenic sulfide was found to have potential anti-cancer activities, especially in gastric cancer. However, the underlying mechanism need to be further explored. This study was aimed to investigate the mechanism of arsenic compounds on gastric cancer.

Methods

Gastric cancer cell lines were infected with lentiviral vector carrying shNFATc3 and/or treated with arsenic sulfide. MTT assay were performed to assess cell growth. Flow cytometer assays were used to detect cell cycle and reactive oxygen species (ROS) level of gastric cancer cells. Western blot was carried out to detect nuclear factor of activated T-cells, cytoplasmic 3 (NFATc3), cell cycle markers, DNA damage pathway protein expression as well as other protein expression in gastric cancer cell lines. The expression of recombination activating gene 1 (RAG1) in gastric cancer cell lines was determined by RNA-sequencing analyses and Real-Time qPCR. The effect of NFATc3 on RAG1 were determined by CHIP-qPCR assay. The effect of arsenic sulfide on AGS cells was evaluated in vivo.

Results

We show that arsenic sulfide as well as knockdown of NFATc3 resulted in increased double-strand DNA damage in gastric cancer cells by increasing the expression of RAG1, an endonuclease essential for immunoglobulin V(D) J recombination. Overexpression of NFATc3 blocked the expression of RAG1 expression and DNA damage induced by arsenic sulfide. Arsenic sulfide induced cellular oxidative stress to redistribute NFATc3, thereby inhibiting its transcriptional function, which can be reversed by N-acetyl-L-cysteine (NAC). We show that NFATc3 targets the promoter of RAG1 for transcriptional inhibition. We further showed that NFATc3 upregulation and RAG1 downregulation significantly associated with poor prognosis in patients with gastric cancer. Our in vivo experiments further confirmed that arsenic sulfide exerted cytotoxic activity against gastric cancer cells through inhibiting NFATc3 to activate RAG1 pathway.

Conclusion

These results demonstrate that arsenic sulfide targets NFATc3 to induce double strand DNA break (DSB) for cell killing through activating RAG1 expression. Our results link arsenic compound to the regulation of DNA damage control and RAG1 expression as a mechanism for its cytotoxic effect.

Linc00423 as a tumor suppressor in retroperitoneal liposarcoma via activing MAPK signaling pathway through destabilizing of NFATC3

Unraveling the noncoding RNA expression networks governing cancer initiation and development is essential while remains largely uncompleted in retroperitoneal liposarcoma (RLS). Through RNA-seq technologies and computational biology, deregulated long noncoding RNAs (lncRNAs) are being identified and reveal that lncRNAs are implicated in serial steps of RLS development. High-throughput sequencing with computational methods for assembling the transcriptome of five paired RLS patient’s tissues. We found that long intergenic noncoding RNA 423 (linc00423) was downregulated in RLS tissues. Gain-of-function assays revealed that overexpressed linc00423 obviously inhibited RLS cell growth in vitro and in vivo. Additionally, RNA sequence, RNA-pulldown and RIP assays evidenced that linc00423 involved in MAPK signaling pathway via destabilizing of nuclear factor of activated T-cells 3 (NFATC3). Summing up, our findings demonstrated that linc00423 acted as the tumor suppressor in RLS cells through regulating the protein level of NFATC3 at a post-transcriptional level and negatively regulated the MAPK signaling pathway at a transcriptional level. Linc00423 might serve as a candidate prognostic biomarker and a target for novel therapies of RLS patients.

NFATc3 plays an oncogenic role in oral/oropharyngeal squamous cell carcinomas by promoting cancer stemness via expression of OCT4

Nuclear factor of activated T cells (NFATc1-c4), a family of transcription factors, is involved in many biological processes by regulating various downstream target genes. However, their role in cancer progression remains controversial. We here report that NFATc3 is the dominant isoform of NFAT in human oral epithelial cells, and its expression was increased in a stepwise manner during the progression of oral/oropharyngeal squamous cell carcinoma (OSCC). More importantly, NFATc3 was highly enriched in self-renewing cancer stem-like cells (CSCs) of OSCC. Increased expression of NFATc3 was required for the maintenance of CSC self-renewal, as NFATc3 inhibition suppressed tumor sphere formation in OSCC cells. Conversely, ectopic NFATc3 expression in non-tumorigenic immortalized oral epithelial cells resulted in the acquisition of self-renewal and increase in CSC phenotype, such as enhanced ALDH1^HIGH cell population, mobility and drug resistance, indicating the functional role of NFATc3 in the maintenance of CSC phenotype. NFATc3 expression also converted the non-tumorigenic oral epithelial cells to malignant phenotypes. Mechanistic investigations further reveal that NFATc3 binds to the promoter of OCT4, a stemness transcription factor, for its activation, thereby promoting CSC phenotype. Moreover, suppression of OCT4 abrogated CSC phenotype in the cell with ectopic NFATc3 overexpression and OSCC, and ectopic OCT4 expression sufficiently induced CSC phenotype. Our study indicates that NFATc3 plays an important role in the maintenance of cancer stemness and OSCC progression via novel NFATc3-OCT4 axis, suggesting that this axis may be a potential therapeutic target for OSCC CSCs.

Anti-liver cancer effect and the mechanism of arsenic sulfide in vitro and in vivo

PURPOSE

This study aimed at investigating the anti-tumor effect of arsenic sulfide (As₂S₂) against liver cancer both in vivo and in vitro and to elucidate its underlying mechanisms.

METHODS

Cell viability of the human hepatocellular carcinoma cell lines SMMC-7721, BEL-7402, HepG2 were measured by CCK-8 assay. The effects of As₂S₂ on cell proliferation and apoptosis of SMMC-7721 cells were investigated using Calcein-AM and PI staining, Hoechst 33258 staining, crystal violet staining, and JC-1 staining. Cell cycle and Annexin V/PI assay were analyzed via flow cytometry. The expression of apoptosis-related proteins, phosphorylation of PI3K and AKT were detected by Western blotting. H22-bearing mice model was established to evaluate the anti-tumor effect of As₂S₂ in vivo. HE staining, PCNA was observed via immunohistochemistry, and TUNEL assay was used to assess the anti-proliferation and pro-apoptotic effects of As₂S₂.

RESULTS

As₂S₂ significantly inhibited the growth of human hepatoma cells SMMC-7721, BEL-7402 and HepG2. As₂S₂ inhibited cell proliferation effectively by inducing G0/G1 cell cycle arrest in SMMC-7721 cells. As₂S₂ could increase Bax/Bcl-2 ratio, decrease mitochondrial membrane potential, promote the release of cytochrome c, increase the levels of cleaved caspase-3 and PARP, indicating that As₂S₂ induced apoptosis in SMMC-7721 cells via mitochondrial-mediated apoptosis pathway. Further research showed that As₂S₂ inhibited the PI3K/AKT signaling pathway leading to apoptotic cell death. In addition, As₂S₂ significantly inhibited tumor growth in H22-bearing mice and induced apoptosis by deactivating PI3K/AKT pathway, which was consistent with the in vitro results.

CONCLUSION

These findings suggested that As₂S₂ could induce apoptosis of liver cancer cells in vitro and in vivo, which was related to PI3K/AKT-mediated mitochondrial pathway and may provide a novel promising therapeutic agent for liver cancer treatment.

Arsenic sulfide amplifies JQ1 toxicity via mitochondrial pathway in gastric and colon cancer cells

Purpose

Gastric and colon cancers have been the leading causes of cancer mortality in the world with limited therapy. Small molecules binding to bromodomains of bromodomain-containing protein 4 (BRD4) exert strong antitumor activities against hematological malignancies, while generally have limited efficacy in advanced solid tumors. Here, we found that the bromodomain and extra-terminal (BET)-bromodomain inhibitor JQ1, when combined with arsenic sulfide (As₄S₄, abbreviated as AS), synergistically decreased the expression of nuclear factor of activated T-cells (NFATs) as well as the downstream oncogene c-Myc and largely induced cell apoptosis via mitochondrial pathway in gastric and colon cancer cell lines.

Methods

The synergistic cytotoxicity of AS and JQ1 in gastric and colon cancer cells was determined by MTT assay and verified by FACS assay. Western blot analysis and quantitative real-time PCR (qPCR) assay were used to detect the expression of NFATs and downstream apoptotic proteins. The mitochondrial transmembrane potential was determined by FACS assay, and the metastasis of cancer cells was detected by the wound-healing assay.

Results

AS and JQ1 synergistically induced cell apoptosis in gastric and colon cancer cells by downregulating NFATs and upregulating apoptotic proteins. Combination of AS and JQ1 was associated with the decreased mitochondrial transmembrane potential, the cytochrome c release, and the subsequent caspase-3 activation.

Conclusion

Thus, our data indicate that AS can effectively enhance the cytotoxicity of BET inhibitors in gastric and colon cancer cells through mitochondrial-mediated apoptosis induction.

Nerve growth factor prevents arsenic-induced toxicity in PC12 cells through the AKT/GSK-3β/NFAT pathway

The potential risk of arsenic-related neurodegeneration has been a growing concern. Arsenic exposure has been reported to disrupt neurite growth and neuron body integrity in vitro; however, its underlying mechanism remains unclear. Previously, we showed that arsenic sulfide (AS) exerted cytotoxicity in gastric and colon cancer cells through regulating nuclear factor of the activated T cells (NFAT) pathway. The NFAT pathway regulates axon path finding and neural development. Using neural crest cell line PC12 cells as a model, here we show that AS caused mitochondrial membrane potential collapse, reactive oxygen species production, and cytochrome c release, leading to mitochondria-mediated apoptosis via the AKT/GSK-3β/NFAT pathway. Increased glycogen synthase kinase-3 beta (GSK-3β) activation leads to the inactivation of NFAT and its antiapoptotic effects. Through inhibiting GSK-3β activity, both nerve growth factor (NGF) and Tideglusib, a GSK-3β inhibitor partially rescued the PC12 cells from the AS-induced cytotoxicity and restored the expression of NFATc3. In addition, overexpression of NFATc3 stimulated neurite outgrowth and potentiated the effect of NGF on promoting the neurite outgrowth. Collectively, our results show that NFATc3 serves as the downstream target of NGF and plays a key role in preventing AS-induced neurotoxicity through regulating the AKT/GSK-3β/NFAT pathway in PC12 cells.