Activation of NFAT signaling establishes a tumorigenic microenvironment through cell autonomous and non-cell autonomous mechanisms

Delayed and limited administration of the JAKinib tofacitinib mitigates chronic DSS-induced colitis

In inflammatory bowel disease, dysregulated T cells express pro-inflammatory cytokines. Using a chronic azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis model resembling ulcerative colitis, we evaluated whether and when treatment with the Janus kinase (JAK) inhibitor tofacitinib could be curative. Comparing the treatment with two and three cycles of tofacitinib medication in drinking water - intermittently with DSS induction - revealed that two cycles were not only sufficient but also superior over the 3-x regimen. The two cycles of the 2-x protocol paralleled the second and third cycles of the longer protocol. T cells were less able to express interferon gamma (IFN-γ) and the serum levels of IFN-γ, interleukin (IL)-2, IL-6, IL-17, and tumor necrosis factor (TNF) were significantly reduced in sera, while those of IL-10 and IL-22 increased under the 2-x protocol. Likewise, the frequency and effector phenotype of regulatory T cells (Tregs) increased. This was accompanied by normal weight gain, controlled clinical scores, and restored stool consistency. The general and histologic appearance of the colons revealed healing and tissue intactness. Importantly, two phases of tofacitinib medication completely prevented AOM-incited pseudopolyps and the hyper-proliferation of epithelia, which was in contrast to the 3-x regimen. This implies that the initial IBD-induced cytokine expression is not necessarily harmful as long as inflammatory signaling can later be suppressed and that time-restricted treatment allows for anti-inflammatory and tissue-healing cytokine activities.

NFATc1 signaling drives chronic ER stress responses to promote NAFLD progression

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) can persist in the stage of simple hepatic steatosis or progress to steatohepatitis (NASH) with an increased risk for cirrhosis and cancer. We examined the mechanisms controlling the progression to severe NASH in order to develop future treatment strategies for this disease.

DESIGN

NFATc1 activation and regulation was examined in livers from patients with NAFLD, cultured and primary hepatocytes and in transgenic mice with differential hepatocyte-specific expression of the transcription factor (Alb-cre, NFATc1^c.a . and NFATc1^Δ/Δ ). Animals were fed with high-fat western diet (WD) alone or in combination with tauroursodeoxycholic acid (TUDCA), a candidate drug for NAFLD treatment. NFATc1-dependent ER stress-responses, NLRP3 inflammasome activation and disease progression were assessed both in vitro and in vivo.

RESULTS

NFATc1 expression was weak in healthy livers but strongly induced in advanced NAFLD stages, where it correlates with liver enzyme values as well as hepatic inflammation and fibrosis. Moreover, high-fat WD increased NFATc1 expression, nuclear localisation and activation to promote NAFLD progression, whereas hepatocyte-specific depletion of the transcription factor can prevent mice from disease acceleration. Mechanistically, NFATc1 drives liver cell damage and inflammation through ER stress sensing and activation of the PERK-CHOP unfolded protein response (UPR). Finally, NFATc1-induced disease progression towards NASH can be blocked by TUDCA administration.

CONCLUSION

NFATc1 stimulates NAFLD progression through chronic ER stress sensing and subsequent activation of terminal UPR signalling in hepatocytes. Interfering with ER stress-responses, for example, by TUDCA, protects fatty livers from progression towards manifest NASH.

Transcriptional analysis of lung fibroblasts identifies PIM1 signaling as a driver of aging-associated persistent fibrosis

Idiopathic pulmonary fibrosis (IPF) is an aging-associated disease characterized by myofibroblast accumulation and progressive lung scarring. To identify transcriptional gene programs driving persistent lung fibrosis in aging, we performed RNA-Seq on lung fibroblasts isolated from young and aged mice during the early resolution phase after bleomycin injury. We discovered that, relative to injured young fibroblasts, injured aged fibroblasts exhibited a profibrotic state characterized by elevated expression of genes implicated in inflammation, matrix remodeling, and cell survival. We identified the proviral integration site for Moloney murine leukemia virus 1 (PIM1) and its target nuclear factor of activated T cells-1 (NFATc1) as putative drivers of the sustained profibrotic gene signatures in injured aged fibroblasts. PIM1 and NFATc1 transcripts were enriched in a pathogenic fibroblast population recently discovered in IPF lungs, and their protein expression was abundant in fibroblastic foci. Overexpression of PIM1 in normal human lung fibroblasts potentiated their fibrogenic activation, and this effect was attenuated by NFATc1 inhibition. Pharmacological inhibition of PIM1 attenuated IPF fibroblast activation and sensitized them to apoptotic stimuli. Interruption of PIM1 signaling in IPF lung explants ex vivo inhibited prosurvival gene expression and collagen secretion, suggesting that targeting this pathway may represent a therapeutic strategy to block IPF progression.

STIM1 is a core trigger of airway smooth muscle remodeling and hyperresponsiveness in asthma

Stromal-interacting molecule 1 (STIM1) proteins are essential for the function of store-operated Ca²⁺ entry (SOCE). Using transcriptomics, metabolomics, imaging, and inducible smooth muscle–specific STIM1 knockout mice expressing genetically encoded Ca²⁺ sensors, we reveal a crucial function of STIM1 in airway remodeling and airway hyperresponsiveness in asthma. STIM1-mediated Ca²⁺ oscillations in airway smooth muscle (ASM) cells are critical for ASM remodeling through metabolic and transcriptional reprogramming and cytokine secretion, including IL-6. These effects are driven by Ca²⁺-dependent activation of the transcription factor isoform NFAT4 specifically in ASM. Our data provide evidence that ASM STIM1 and SOCE are central triggers of asthma manifestations and advocate for the future use of STIM1 as a molecular target in asthma therapy.

Airway remodeling and airway hyperresponsiveness are central drivers of asthma severity. Airway remodeling is a structural change involving the dedifferentiation of airway smooth muscle (ASM) cells from a quiescent to a proliferative and secretory phenotype. Here, we show up-regulation of the endoplasmic reticulum Ca²⁺ sensor stromal-interacting molecule 1 (STIM1) in ASM of asthmatic mice. STIM1 is required for metabolic and transcriptional reprogramming that supports airway remodeling, including ASM proliferation, migration, secretion of cytokines and extracellular matrix, enhanced mitochondrial mass, and increased oxidative phosphorylation and glycolytic flux. Mechanistically, STIM1-mediated Ca²⁺ influx is critical for the activation of nuclear factor of activated T cells 4 and subsequent interleukin-6 secretion and transcription of pro-remodeling transcription factors, growth factors, surface receptors, and asthma-associated proteins. STIM1 drives airway hyperresponsiveness in asthmatic mice through enhanced frequency and amplitude of ASM cytosolic Ca²⁺ oscillations. Our data advocates for ASM STIM1 as a target for asthma therapy.

NFAT2-HDAC1 signaling contributes to the malignant phenotype of glioblastoma

BACKGROUND

Deregulation of the nuclear factor of activated T cell (NFAT) pathway has been reported in several human cancers. Particularly, NFAT2 is involved in the malignant transformation of tumor cells and is identified as an oncogene. However, the role of NFAT2 in glioblastoma (GBM) is largely unknown.

METHODS

The expression and prognostic value of NFAT2 were examined in the databases of the Repository of Molecular Brain Neoplasia Data and The Cancer Genome Atlas (TCGA) and clinical samples. The functional effects of silencing or overexpression of NFAT2 were evaluated in glioma stem cell (GSC) viability, invasion, and self-renewal in vitro and in tumorigenicity in vivo. The downstream target of NFAT2 was investigated.

RESULTS

High NFAT2 expression was significantly associated with mesenchymal (MES) subtype and recurrent GBM and predicted poor survival. NFAT2 silencing inhibited the invasion and clonogenicity of MES GSC-enriched spheres in vitro and in vivo. NFAT2 overexpression promoted tumor growth and MES differentiation of GSCs. A TCGA database search showed that histone deacetylase 1 (HDAC1) expression was significantly correlated with that of NFAT2. NFAT2 regulates the transcriptional activity of HDAC1. Rescue of HDAC1 in NFAT2-knockdown GSCs partially restored tumor growth and MES phenotype. Loss of NFAT2 and HDAC1 expression resulted in hyperacetylation of nuclear factor-kappaB (NF-κB), which inhibits NF-κB-dependent transcriptional activity.

CONCLUSION

Our findings suggest that the NFAT2-HDAC1 pathway might play an important role in the maintenance of the malignant phenotype and promote MES transition in GSCs, which provide potential molecular targets for the treatment of GBMs.

Gene expression profile involved in signaling and apoptosis of osteoblasts in contact with cellulose/MWCNTs scaffolds

The aim of this work was to evaluate the expression profile of genes involved in signaling, intracellular and extracellular Ca⁺² concentration and apoptosis pathways of osteoblasts in contact with a scaffold made of a composite of BCN/MWCNTs. Osteoblasts were cultivated on BCN, MWCNTs and their mixtures. Osteoblast RNA was extracted for sintering cDNA to amplify genes of interest by PCR; intra- and extracellular calcium (Ca²⁺⁾ was also quantified. Regarding the genes that participate in the regulation paths (MAPK and NF-KB), it was found that only the expression of NF-KB was affected in all treatments. The expression of VEGFA increased, except in the treatment of high concentration of MWCNTs, where remained unchanged. The expression of genes Apaf-1 and Bcl-2/Bax and TP53 increased as compared to the control (except for TP53 in BC and C1/MWCNTs) indicating that cells are responding to the presence of BCN-MWCNTs composites scaffolds. The results suggest that osteoblast developed a modification in the expression profile of genes that actively participate in cellular processes such as proliferation, vasculogenesis and apoptosis, which may be modulated by the increase of intra- and extracellular Ca²⁺ concentration.

NFAT2 overexpression suppresses the malignancy of hepatocellular carcinoma through inducing Egr2 expression

BACKGROUND

Nuclear factor of activated T cells 2 (NFAT2) has been reported to regulate the development and malignancy of few tumors. In this study, we aimed to explore the effect of NFAT2 expression on cell fate of HepG2 cell and its potential mechanisms.

METHODS

Firstly, the pcDNA3.1-NFAT2 plasmid was transfected into HepG2 cells to construct NFAT2 overexpressed HepG2 cells. Then, the chemical count kit-8 cell viability assay, Annexin V-FITC apoptosis detection, EdU labeling proliferation detection, transwell and wound healing experiments were performed. The expression of Egr2 and FasL, and the phosphorylation of AKT and ERK, after ionomycin and PMA co-stimulation, was detected, while the Ca2+ mobilization stimulated by K+ solution was determined. At last, the mRNA and protein expression of NFAT2, Egr2, FasL, COX-2 and c-myc in carcinoma and adjacent tissues was investigated.

RESULTS

The NFAT2 overexpression suppressed the cell viability, invasion and migration capabilities, and promoted apoptosis of HepG2 cells. NFAT2 overexpression induced the expression of Egr2 and FasL and suppressed the phosphorylation of AKT and ERK. The sensitivity and Ca2+ mobilization of HepG2 cells was also inhibited by NFAT2 overexpression. Compared with adjacent tissues, the carcinoma tissues expressed less NFAT2, Egr2, FasL and more COX-2 and c-myc.

CONCLUSION

The current study firstly suggested that NFAT2 suppressed the aggression and malignancy of HepG2 cells through inducing the expression of Egr2. The absence of NFAT2 and Egr2 in carcinoma tissues reminded us that NFAT2 may be a promising therapeutic target for hepatocellular carcinoma treatment.

Creation of a Prognostic Risk Prediction Model for Lung Adenocarcinoma Based on Gene Expression, Methylation, and Clinical Characteristics

Background

This study aimed to identify important marker genes in lung adenocarcinoma (LACC) and establish a prognostic risk model to predict the risk of LACC in patients.

Material/Methods

Gene expression and methylation profiles for LACC and clinical information about cases were downloaded from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases, respectively. Differentially expressed genes (DEGs) and differentially methylated genes (DMGs) between cancer and control groups were selected through meta-analysis. Pearson coefficient correlation analysis was performed to identify intersections between DEGs and DMGs and a functional analysis was performed on the genes that were correlated. Marker genes and clinical factors significantly related to prognosis were identified using univariate and multivariate Cox regression analyses. Risk prediction models were then created based on the marker genes and clinical factors.

Results

In total, 1975 DEGs and 2095 DMGs were identified. After comparison, 16 prognosis-related genes (EFNB2, TSPAN7, INPP5A, VAMP2, CALML5, SNAI2, RHOBTB1, CKB, ATF7IP2, RIMS2, RCBTB2, YBX1, RAB27B, NFATC1, TCEAL4, and SLC16A3) were selected from 265 overlapping genes. Four clinical factors (pathologic N [node], pathologic T [tumor], pathologic stage, and new tumor) were associated with prognosis. The prognostic risk prediction models were constructed and validated with other independent datasets.

Conclusions

An integrated model that combines clinical factors and gene markers is useful for predicting risk of LACC in patients. The 16 genes that were identified, including EFNB2, TSPAN7, INPP5A, VAMP2, and CALML5, may serve as novel biomarkers for diagnosis of LACC and prediction of disease prognosis.

Phenformin Promotes Keratinocyte Differentiation via the Calcineurin/NFAT Pathway

Phenformin is a drug in the biguanide class that was previously used to treat type 2 diabetes. We have reported the antitumor activities of phenformin to enhance the efficacy of BRAF-MAPK kinase-extracellular signal-regulated kinase pathway inhibition and to inhibit myeloid-derived suppressor cells in various melanoma models. Here we demonstrate that phenformin suppresses tumor growth and promotes keratinocyte differentiation in the 7,12-dimethylbenz[a]anthracene/12-O-tetradecanoylphorbol-13-acetate two-stage skin carcinogenesis mouse model. Moreover, phenformin enhances the suspension-induced differentiation of mouse and human keratinocytes. Mechanistically, phenformin induces the nuclear translocation of NFATc1 in keratinocytes in an AMPK-dependent manner. Pharmacologic or genetic inhibition of calcineurin and NFAT signaling reverses the effects of phenformin on keratinocyte differentiation. Taken together, our study reveals an antitumor activity of phenformin to promote keratinocyte differentiation that warrants future translational efforts to repurpose phenformin for the treatment of cutaneous squamous cell carcinomas.

Role of the calcium toolkit in cancer stem cells

Cancer stem cells are a subpopulation of tumor cells that proliferate, self-renew and produce more differentiated tumoral cells building-up the tumor. Responsible for the sustained growth of malignant tumors, cancer stem cells are proposed to play significant roles in cancer resistance to standard treatment and in tumor recurrence. Among the mechanisms dysregulated in neoplasms, those related to Ca²⁺ play significant roles in various aspects of cancers. Ca²⁺ is a ubiquitous second messenger whose fluctuations of its intracellular concentrations are tightly controlled by channels, pumps, exchangers and Ca²⁺ binding proteins. These components support the genesis of Ca²⁺ signals with specific spatio-temporal characteristics that define the cell response. Being involved in the coupling of extracellular events with intracellular responses, the Ca²⁺ toolkit is often hijacked by cancer cells to promote notably their proliferation and invasion. Growing evidence obtained during the last decade pointed to a role of Ca²⁺ handling and mishandling in cancer stem cells. In this review, after a general overview of the concept of cancer stem cells we analyse and discuss the studies and current knowledge regarding the complex roles of Ca²⁺ toolkit and signaling in these cells. We highlight that numbers of Ca²⁺ signaling actors promote cancer stem cell state and are associated with cell resistance to current cancer treatments and thus may represent promising targets for potential clinical applications.

Camphor white oil induces tumor regression through cytotoxic T cell-dependent mechanisms

Bioactive derivatives from the camphor laurel tree, Cinnamomum camphora, are posited to exhibit chemopreventive properties but the efficacy and mechanism of these natural products are not fully understood. We tested an essential-oil derivative, camphor white oil (CWO), for anti-tumor activity in a mouse model of keratinocyte-derived skin cancer. Daily topical treatment with CWO induced dramatic regression of pre-malignant skin tumors and a two-fold reduction in cutaneous squamous cell carcinomas. We next investigated underlying cellular and molecular mechanisms. In cultured keratinocytes, CWO stimulated calcium signaling, resulting in calcineurin-dependent activation of nuclear factor of activated T cells (NFAT). In vivo, CWO induced transcriptional changes in immune-related genes identified by RNA-sequencing, resulting in cytotoxic T cell-dependent tumor regression. Finally, we identified chemical constituents of CWO that recapitulated effects of the admixture. Together, these studies identify T cell-mediated tumor regression as a mechanism through which a plant-derived essential oil diminishes established tumor burden.

Arsenite increases Cyclin D1 expression through coordinated regulation of the Ca2+/NFAT2 and NF-κB pathways via ERK/MAPK in a human uroepithelial cell line

To understand the direct link between Cyclin D1, and nuclear factor of activated T cells 2 (NFAT2) and nuclear factor (NF)-κB in arsenic-treated bladder cells, as well as the association between MAPK and NFAT signaling, we determined whether or not the Ca²⁺/NFAT pathway is activated in an arsenic-treated normal urothelial cell line and determined the roles of NFAT and NF-κB signals in the regulation of Cyclin D1 expression. The SV-40 immortalized human uroepithelial cell line, SV-HUC-1, was treated with NaAsO₂ for 24 h (0, 1, 2, 4, 8, and 10 μM) and 10, 20, 30, and 40 weeks (0 and 0.5 μM). We found that arsenite increased the intracellular Ca²⁺ levels and induced NFAT2 nuclear translocation after treatment for 24 h. The level of NFAT2 mRNA and expression of total protein and nuclear protein were increased after long-term treatment with 0.5 μM arsenite for 30 and 40 weeks compared to the cells treated for 24 h. In addition, NF-κB p50 and p65 nuclear protein expression increased significantly in cells treated with 2-8 μM arsenite for 24 h, which was consistent with NFAT2 nuclear expression. Furthermore, an ERK inhibitor (U0126) significantly reduced the expression of NFAT2 nuclear protein, and an ERK and JNK inhibitor decreased the levels of p65 and p50 nuclear protein. Cyclin D1 is known as a proto-oncogene and the level of this protein was increased in SV-HUC-1 cells treated with arsenite for 24 h and long-term. An NFAT inhibitor (CsA) and NF-κB inhibitor (PDTC) all markedly reduced Cyclin D1 protein expression. Treatment with U0126 also significantly decreased Cyclin D1 protein expression while JNK and p38 inhibitors did not attenuate the arsenite-associated increase in Cyclin D1 protein expression. The results suggest that regulation of Cyclin D1 protein expression by arsenite in SV-HUC-1 cells is dependent on ERK/NFAT2 and ERK/NF-κB, but is not dependent on JNK or p38.

Ca2+/nuclear factor of activated T cells signaling is enriched in early-onset rectal tumors devoid of canonical Wnt activation

Our previous extensive analysis revealed a significant proportion of early-onset colorectal tumors from India to be localized to the rectum in younger individuals and devoid of deregulated Wnt/β-catenin signaling. In the current study, we performed a comprehensive genome-wide analysis of clinically well-annotated microsatellite stable early-onset sporadic rectal cancer (EOSRC) samples. Results revealed extensive DNA copy number alterations in rectal tumors in the absence of deregulated Wnt/β-catenin signaling. More importantly, transcriptome profiling revealed a (non-Wnt/β-catenin, non-MSI) genetic signature that could efficiently and specifically identify Wnt- rectal cancer. The genetic signature included a significant representation of genes belonging to Ca²⁺/NFAT signaling pathways that were validated in additional samples. The validated NFAT target genes exhibited significantly higher expression levels than canonical Wnt/β-catenin targets in Wnt- samples, an observation confirmed in other CRC expression data sets as well. We confirmed the validated genes to be transcriptionally regulated by NFATc1 by (a) evaluating their respective transcript levels and (b) performing promoter-luciferase and chromatin immunoprecipitation assays following ectopic expression as well as knockdown of NFATc1 in CRC cells. NFATc1 and its targets RUNX2 and GSN could drive increased migration in CRC cells. Finally, the validated genes were associated with poor survival in the cancer genome atlas CRC expression data set. This study is the first comprehensive molecular characterization of EOSRC that appears to be driven by noncanonical tumorigenesis pathways.

KEY MESSAGES

Early-onset sporadic rectal cancer exhibits DNA gain and loss without Wnt activation. Ca²⁺/NFAT signaling appears to be activated in the absence of Wnt activation. An eight-gene genetic signature distinguishes Wnt+ and Wnt- rectal tumors. NFAT and its target genes regulate tumorigenic properties in CRC cells.

Gene and miRNA expression signature of Lewis lung carcinoma LLC1 cells in extracellular matrix enriched microenvironment

Background

The extracellular matrix (ECM), one of the key components of tumor microenvironment, has a tremendous impact on cancer development and highly influences tumor cell features. ECM affects vital cellular functions such as cell differentiation, migration, survival and proliferation. Gene and protein expression levels are regulated in cell-ECM interaction dependent manner as well. The rate of unsuccessful clinical trials, based on cell culture research models lacking the ECM microenvironment, indicates the need for alternative models and determines the shift to three-dimensional (3D) laminin rich ECM models, better simulating tissue organization. Recognized advantages of 3D models suggest the development of new anticancer treatment strategies. This is among the most promising directions of 3D cell cultures application. However, detailed analysis at the molecular level of 2D/3D cell cultures and tumors in vivo is still needed to elucidate cellular pathways most promising for the development of targeted therapies. In order to elucidate which biological pathways are altered during microenvironmental shift we have analyzed whole genome mRNA and miRNA expression differences in LLC1 cells cultured in 2D or 3D culture conditions.

Methods

In our study we used DNA microarrays for whole genome analysis of mRNA and miRNA expression differences in LLC1 cells cultivated in 2D or 3D culture conditions. Next, we indicated the most common enriched functional categories using KEGG pathway enrichment analysis. Finally, we validated the microarray data by quantitative PCR in LLC1 cells cultured under 2D or 3D conditions or LLC1 tumors implanted in experimental animals.

Results

Microarray gene expression analysis revealed that 1884 genes and 77 miRNAs were significantly altered in LLC1 cells after 48 h cell growth under 2D and ECM based 3D cell growth conditions. Pathway enrichment results indicated metabolic pathway, MAP kinase, cell adhesion and immune response as the most significantly altered functional categories in LLC1 cells due to the microenvironmental shift from 2D to 3D. Comparison of the expression levels of selected genes and miRNA between LLC1 cells grown in 3D cell culture and LLC1 tumors implanted in the mouse model indicated correspondence between both model systems.

Conclusions

Global gene and miRNA expression analysis in LLC1 cells under ECM microenvironment indicated altered immune response, adhesion and MAP kinase pathways. All these processes are related to tumor development, progression and treatment response, suggesting the most promising directions for the development of targeted therapies using the 3D cell culture models.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2825-9) contains supplementary material, which is available to authorized users.

Luteolin and apigenin activate the Oct-4/Sox2 signal via NFATc1 in human periodontal ligament cells

Identifying small molecules to activate the Oct-4/Sox2-derived pluripotency network represents a hopeful and safe method to pluripotency without genetic manipulation. Luteolin and apigenin, two major bioactive flavonoids, enhance reprogramming efficiency and increase expression of Oct-4/Sox2/c-Myc, albeit the detailed mechanism regulating pluripotency in dental-derived cells remains unknown. In the present study, to elucidate the effect of luteolin/apigenin on pluripotency of periodontal ligament cells (PDLCs) through interaction with downstream signals, we examined cell cycle, proliferation, apoptosis, expression of Oct-4/Sox2/c-Myc, and multilineage differentiation of PDLCs with luteolin/apigenin treatment. Moreover, we profiled the differentially expressed pluripotency genes by PCR arrays. Our results demonstrated that luteolin/apigenin restrained cell proliferation, increased apoptosis, and arrested PDLCs in G2/M and S phase. Luteolin and apigenin activated expression of Oct-4, Sox2, and c-Myc in a time- and dose-dependent pattern, and repressed lineage-specific differentiation. PCR arrays profiled multiple signals in PDLCs with luteolin/apigenin treatment, among which NFATc1 was the major upregulated gene. Notably, blocking of the NFATc1 signal with INCA-6 significantly decreased mRNA and protein expression of Oct-4, Sox2, and c-Myc in PDLCs with luteolin/apigenin treatment, indicating that NFATc1 may act as an upstream modulator of Oct-4/Sox2 signal. Taken together, this study showed that luteolin and apigenin effectively maintain pluripotency of PDLCs through activation of Oct-4/Sox2 signal via NFATc1.

NFATc1 regulates cell proliferation, migration, and invasion of ovarian cancer SKOV3 cells in vitro and in vivo

NFATc1 (nuclear factor of activated T‑cells c1) is associated with malignancy in several cancer models. However, the expression and function of NFATc1 in ovarian cancer remain elusive. In the present study, we investigated the role of NFATc1 in human epithelial ovarian cancer (EOC) using human ovarian adenocarcinoma SKOV3 cells and patient characteristics. NFATc1 expression was silenced by siRNA in the SKOV3 ovarian cancer cell line and in human ovarian cancer nude mouse xenografts. Real‑time PCR, western blotting, immunohistochemical staining, MTT, flow cytometry, transwell, erasion trace and mouse assays were used to detect NFATc1 expression, cell proliferation, apoptosis, cell invasion and migration, tumor growth and angiogenesis. Survival analysis was performed to assess the correlation between NFATc1 expression and survival. NFATc1 was overexpressed in the SKOV3 ovarian cancer cell line and in human serous/mucinous ovarian cancer tissues. The silencing of NFATc1 expression by siRNA reduced cell proliferation and migration and promoted apoptosis in vitro and decreased the ovarian cancer cell tumorigenesis in vivo in nude mice. NFATc1 overexpression in high‑grade serous ovarian carcinomas was an independent prognostic factor of poor overall survival and of early relapse (P<0.01) in a univariate analysis. Our present data provide evidence that NFATc1 is overexpressed in human serous/mucinous ovarian cancer and is associated with a poor prognosis. NFATc1 silencing regulates the cell cycle, apoptosis, invasion and migration. NFATc1 thus has the potential to be a therapeutic target and to be used in EOC diagnosis and prognosis.

DNA damage-induced apoptosis suppressor (DDIAS), a novel target of NFATc1, is associated with cisplatin resistance in lung cancer

In a previous study, we reported that DNA damage induced apoptosis suppressor (DDIAS; hNoxin), a human homolog of mouse Noxin, functions as an anti-apoptotic protein in response to DNA repair. Here we reveal that DDIAS is a target gene of nuclear factor of activated T cells 2 (NFATc1) and is associated with cisplatin resistance in lung cancer cells. In the DDIAS promoter analysis, we found that NFATc1 activated the transcription of DDIAS through binding to NFAT consensus sequences in the DDIAS promoter. In addition, tissue array immunostaining revealed a correlation between DDIAS and NFATc1 expression in human lung tumors. NFATc1 knockdown or treatment with the NFAT inhibitor cyclosporine A induced apoptosis and led to growth inhibition of lung cancer cells, indicating the functional relevance of both the proteins. In contrast, DDIAS overexpression overcame this NFATc1 knockdown-induced growth inhibition, supporting the cancer-specific role of DDIAS as a target gene of NFATc1. NFATc1 or DDIAS inhibition clearly enhanced apoptosis induced by cisplatin in NCI-H1703 and A549 cells. Conversely, DDIAS overexpression rescued NCI-H1703 cells from cisplatin-mediated cell death and caspase-3/7 activation. These results suggest that NFATc1-induced DDIAS expression contributes to cisplatin resistance, and targeting DDIAS or NFATc1 impairs the mechanism regulating cisplatin resistance in lung cancer cells. Taken together, DDIAS is a target of NFATc1 and is associated with cisplatin resistance in lung cancer cells.

NFATc1 promotes prostate tumorigenesis and overcomes PTEN loss-induced senescence

Despite recent insights into prostate cancer (PCa)-associated genetic changes, full understanding of prostate tumorigenesis remains elusive due to complexity of interactions among various cell types and soluble factors present in prostate tissue. We found upregulation of Nuclear Factor of Activated T Cells c1 (NFATc1) in human PCa and cultured PCa cells, but not in normal prostates and non-tumorigenic prostate cells. To understand the role of NFATc1 in prostate tumorigenesis in situ, we temporally and spatially controlled the activation of NFATc1 in mouse prostate and showed that such activation resulted in prostatic adenocarcinoma with features similar to those seen in human PCa. Our results indicate that the activation of a single transcription factor, NFATc1 in prostatic luminal epithelium to PCa can affect expression of diverse factors in both cells harboring the genetic changes and in neighboring cells through microenvironmental alterations. In addition to the activation of oncogenes c-MYC and STAT3 in tumor cells, a number of cytokines and growth factors, such as IL1β, IL6, and SPP1 (Osteopontin, a key biomarker for PCa), were upregulated in NFATc1-induced PCa, establishing a tumorigenic microenvironment involving both NFATc1 positive and negative cells for prostate tumorigenesis. To further characterize interactions between genes involved in prostate tumorigenesis, we generated mice with both NFATc1 activation and Pten inactivation in prostate. We showed that NFATc1 activation led to acceleration of Pten-null–driven prostate tumorigenesis by overcoming the PTEN loss–induced cellular senescence through inhibition of p21 activation. This study provides direct in vivo evidence of an oncogenic role of NFATc1 in prostate tumorigenesis and reveals multiple functions of NFATc1 in activating oncogenes, in inducing proinflammatory cytokines, in oncogene addiction, and in overcoming cellular senescence, which suggests calcineurin-NFAT signaling as a potential target in preventing PCa.

Loss of endogenous Nfatc1 reduces the rate of DMBA/TPA-induced skin tumorigenesis

Immunosuppressive therapies using calcineurin inhibitors, such as cyclosporine A, are associated with a higher incidence of squamous cell carcinoma formation in mice and humans. Calcineurin is believed to suppress tumorigenesis in part through Nfatc1, a transcription factor expressed primarily in hair follicle bulge stem cells in mice. However, mice overexpressing a constitutively active Nfatc1 isoform in the skin epithelium developed increased spontaneous skin squamous cell carcinomas. Because follicular stem cells can contribute to skin tumorigenesis, whether the endogenous expression of Nfatc1 inhibits or enhances skin tumorigenesis is unclear. Here we show that loss of the endogenous expression of Nfatc1 suppresses the rate of DMBA/TPA-induced skin tumorigenesis. Inducible deletion of Nfatc1 in follicular stem cells before tumor initiation significantly reduces the rate of tumorigenesis and the contribution of follicular stem cells to skin tumors. We find that skin tumors from mice lacking Nfatc1 display reduced Hras codon 61 mutations. Furthermore, Nfatc1 enhances the expression of genes involved in DMBA metabolism and increases DMBA-induced DNA damage in keratinocytes. Together these data implicate Nfatc1 in the regulation of skin stem cell-initiated tumorigenesis via the regulation of DMBA metabolism.

Tissue Factor-Factor VII Complex As a Key Regulator of Ovarian Cancer Phenotypes

Tissue factor (TF) is an integral membrane protein widely expressed in normal human cells. Blood coagulation factor VII (fVII) is a key enzyme in the extrinsic coagulation cascade that is predominantly secreted by hepatocytes and released into the bloodstream. The TF–fVII complex is aberrantly expressed on the surface of cancer cells, including ovarian cancer cells. This procoagulant complex can initiate intracellular signaling mechanisms, resulting in malignant phenotypes. Cancer tissues are chronically exposed to hypoxia. TF and fVII can be induced in response to hypoxia in ovarian cancer cells at the gene expression level, leading to the autonomous production of the TF–fVII complex. Here, we discuss the roles of the TF–fVII complex in the induction of malignant phenotypes in ovarian cancer cells. The hypoxic nature of ovarian cancer tissues and the roles of TF expression in endometriosis are discussed. Arguments will be extended to potential strategies to treat ovarian cancers based on our current knowledge of TF–fVII function.

A novel role for an RCAN3-derived peptide as a tumor suppressor in breast cancer

The members of the human regulators of calcineurin (RCAN) protein family are endogenous regulators of the calcineurin (CN)-cytosolic nuclear factor of activated T-cells (NFATc) pathway activation. This function is explained by the presence of a highly conserved calcipressin inhibitor of calcineurin (CIC) motif in RCAN proteins, which has been shown to compete with NFATc for the binding to CN and therefore are able to inhibit NFATc dephosphorylation and activation by CN. Very recently, emerging roles for NFATc proteins in transformation, tumor angiogenesis and metastasis have been described in different cancer cell types. In this work, we report that the overexpression of RCAN3 dramatically inhibits tumor growth and tumor angiogenesis in an orthotopic human breast cancer model. We suggest that RCAN3 exerts these effects in a CN-dependent manner, as mutation of the CIC motif in RCAN3 abolishes the tumor suppressor effect. Moreover, the expression of the EGFP-R3(178-210) peptide, spanning the CIC motif of RCAN3, is able to reproduce all the antitumor effects of RCAN3 full-length protein. Finally, we show that RCAN3 and the EGFP-R3(178-210) peptide inhibit the CN-NFATc signaling pathway and the induction of the NFATc-dependent gene cyclooxygenase-2. Our work suggests that the EGFP-R3(178-210) peptide possess potent tumor suppressor properties and therefore constitutes a novel lead for the development of potent and specific antitumoral agents. Moreover, we propose the targeting of the CN-NFATc pathway in the tumor cells constitutes an effective way to hamper tumor progression by impairing the paracrine network among tumor, endothelial and polymorphonucleated cells.

Nuclear factor of activated T cells in cancer development and treatment

Since nuclear factor of activated T cells (NFAT) was first identified as a transcription factor in T cells, various NFAT isoforms have been discovered and investigated. Accumulating studies have suggested that NFATs are involved in many aspects of cancer, including carcinogenesis, cancer cell proliferation, metastasis, drug resistance and tumor microenvironment. Different NFAT isoforms have distinct functions in different cancers. The exact function of NFAT in cancer or the tumor microenvironment is context dependent. In this review, we summarize our current knowledge of NFAT regulation and function in cancer development and treatment. NFATs have emerged as a potential target for cancer prevention and therapy.

NFAT1 promotes intratumoral neutrophil infiltration by regulating IL8 expression in breast cancer

NFAT transcription factors are key regulators of gene expression in immune cells. In addition, NFAT1-induced genes play diverse roles in mediating the progression of various solid tumors. Here we show that NFAT1 induces the expression of the IL8 gene by binding to its promoter and leading to IL8 secretion. Thapsigargin stimulation of breast cancer cells induces IL8 expression in an NFAT-dependent manner. Moreover, we show that NFAT1-mediated IL8 production promotes the migration of primary human neutrophils in vitro and also promotes neutrophil infiltration in tumor xenografts. Furthermore, expression of active NFAT1 effectively suppresses the growth of nascent and established tumors by a non cell-autonomous mechanism. Evaluation of breast tumor tissue reveals that while the levels of NFAT1 are similar in tumor cells and normal breast epithelium, cells in the tumor stroma express higher levels of NFAT1 compared to normal stroma. Elevated levels of NFAT1 also correlate with increased neutrophil infiltrate in breast tumors. These data point to a mechanism by which NFAT1 orchestrates the communication between breast cancer cells and host neutrophils during breast cancer progression.

Inflammation-induced NFATc1-STAT3 transcription complex promotes pancreatic cancer initiation by KrasG12D

Cancer-associated inflammation is a molecular key feature in pancreatic ductal adenocarcinoma. Oncogenic KRAS in conjunction with persistent inflammation is known to accelerate carcinogenesis, although the underlying mechanisms remain poorly understood. Here, we outline a novel pathway whereby the transcription factors NFATc1 and STAT3 cooperate in pancreatic epithelial cells to promote Kras(G12D)-driven carcinogenesis. NFATc1 activation is induced by inflammation and itself accelerates inflammation-induced carcinogenesis in Kras(G12D) mice, whereas genetic or pharmacologic ablation of NFATc1 attenuates this effect. Mechanistically, NFATc1 complexes with STAT3 for enhancer-promoter communications at jointly regulated genes involved in oncogenesis, for example, Cyclin, EGFR and WNT family members. The NFATc1-STAT3 cooperativity is operative in pancreatitis-mediated carcinogenesis as well as in established human pancreatic cancer. Together, these studies unravel new mechanisms of inflammatory-driven pancreatic carcinogenesis and suggest beneficial effects of chemopreventive strategies using drugs that are currently available for targeting these factors in clinical trials.

SIGNIFICANCE

Our study points to the existence of an oncogenic NFATc1-STAT3 cooperativity that mechanistically links inflammation with pancreatic cancer initiation and progression. Because NFATc1-STAT3 nucleoprotein complexes control the expression of gene networks at the intersection of inflammation and cancer, our study has significant relevance for potentially managing pancreatic cancer and other inflammatory-driven malignancies.