Signal integration by transcription-factor assemblies: interactions of NF-AT1 and AP-1 on the IL-2 promoter

RNA Therapeutics for Improving CAR T-cell Safety and Efficacy

Autologous chimeric antigen receptor (CAR) T cells have recently emerged as potent tools in the fight against cancer, with promising therapeutic efficacy against hematological malignancies. However, several limitations hamper their widespread clinical use, including availability of target antigen, severe toxic effects, primary and secondary resistance, heterogeneous quality of autologous T cells, variable persistence, and low activity against solid tumors. Development of allogeneic off-the-shelf CAR T cells could help address some of these limitations but is impeded by alloimmunity with either rejection and limited expansion of allo-CAR T cells or CAR T cells versus host reactions. RNA therapeutics, such as small interfering RNAs, microRNAs, and antisense oligonucleotides, are able to silence transcripts in a sequence-specific and proliferation-sensitive way, which may offer a way to overcome some of the challenges facing CAR T-cell development and clinical utility. Here, we review how different RNA therapeutics or a combination of RNA therapeutics and genetic engineering could be harnessed to improve the safety and efficacy of autologous and allogeneic CAR T-cell therapy.

Murine RAW Macrophages Are a Suitable Model to Study the CD3 Signaling in Myeloid Cells

In recent years, a growing body of evidence has shown the presence of a subpopulation of macrophages that express CD3, especially in the context of mycobacterial infections. Despite these findings, the function of these cells has been poorly understood. Furthermore, the low frequency of CD3+ macrophages in humans limits the study of this subpopulation. This work aimed to evaluate the expression of CD3 in a murine macrophage cell line and its potential for the study of CD3 signaling. The murine macrophage cell line RAW was used to evaluate CD3 expression at the transcriptional and protein levels and the effect of in vitro infection with the Mycobacterium bovis Bacillus Calmette-Guérin (BCG) on these. Our data showed that RAW macrophages express CD3, both the ε and ζ chains, and it is further increased at the transcriptional level after BCG infection. Furthermore, our data suggest that CD3 can be found on the cell surface and intracellularly. However, this molecule is internalized constantly, mainly after activation with anti-CD3 stimulus, but interestingly, it is stably maintained at the transcriptional level. Finally, signaling proteins such as NFAT1, c-Jun, and IKK-α are highly expressed in RAW macrophages. They may play a role in the CD3-controlled signaling pathway to deliver inflammatory cytokines such as TNF and IL-6. Our study provides evidence to support that RAW cells are a suitable model to study the function and signaling of the CD3 complex in myeloid cells.

The Trinity of Matrix Metalloproteinases, Inflammation, and Cancer: A Literature Review of Recent Updates

The critical link between cancer and inflammation has been known for many years. This complex network was further complexed by revealing the association of the matrix metalloproteinase family members with inflammatory cytokines, which were previously known to be responsible for the development of metastasis. This article summarizes the current studies which evaluate the relationship between cancer and inflammatory microenvironment as well as the roles of MMPs on invasion and metastasis together.

Cross‑validation of genes potentially associated with neoadjuvant chemotherapy and platinum‑based chemoresistance in epithelial ovarian carcinoma

Ovarian carcinomas have the poorest prognosis and the highest mortality among gynecological malignancies. Neoadjuvant chemotherapy (NACT) is considered as a novel therapeutic strategy and an alternative treatment for advanced epithelial ovarian cancer (AEOC). The aim of the present study was to identify the core genes related to platinum‑based NACT resistance in AEOC and to allow screening at the molecular level for the most appropriate ovarian cancer patients for NACT. We obtained three drug‑resistant microarrays GSE114206, GSE41499 and GSE33482 from the Gene Expression Omnibus (GEO) database as well as a microarray representing NACT, GSE109934. Bioinformatics analysis revealed the nature of the four potential candidate genes for using in functional enrichment analyses and interaction network construction. The potential associations and possible genetic alterations among the DEGs were summarized using the STRING database in Cytoscape and the cBioPortal visualization tool, respectively. A total of 63 genes were identified as DEGs from GSE109934 representing NACT. From the drug‑resistant GSE114206 and GSE41499 datasets, 106 DEGs containing 36 upregulated genes and 70 downregulated genes were selected, and from the drug‑resistant GSE114206 and GSE33482 datasets, 406 DEGs with 157 upregulated genes and 249 downregulated genes were selected. The 36 upregulated DEGs and the 70 downregulated genes were notably abundant in the different categories. In KEGG pathway analysis, the 157 upregulated genes and the 249 downregulated genes were concentrated in distinctive signaling pathways. Four potential genes associated with NACT and platinum‑based chemoresistance were screened, including nuclear factor of activated T‑cells, cytoplasmic 1 (NAFTc1), Kruppel‑like factor 4 (KLF4), nuclear receptor subfamily 4 group A member 3 (NR4A3) and hepatocyte growth factor (HGF). Our study showed that the mRNA expression levels of NAFTc1, NR4A3 and HGF were increased in drug‑resistant OC cell lines (all P<0.01), whereas the mRNA expression levels of KLF4 were notably lower in the SKOV3‑CDDP and HeyA8‑CDDP cell line (all P<0.01) but higher in the A2780‑CBP cell line. The NAFTc1, KLF4, NR4A3 and HGF genes may be potential therapeutic targets for NACT and platinum‑based chemoresistance factors as well as candidate biomarkers in AEOC. Determination of the expression levels of these four genes in tumor tissues before planning NACT treatment or initial surgery would be beneficial for AEOC patients.

Glycogen Synthase Kinase-3β Facilitates Cytokine Production in 12-O-Tetradecanoylphorbol-13-Acetate/Ionomycin-Activated Human CD4+ T Lymphocytes

Cytokines are the major immune regulators secreted from activated CD4⁺ T lymphocytes that activate adaptive immunity to eradicate nonself cells, including pathogens, tumors, and allografts. The regulation of glycogen synthase kinase (GSK)-3β, a serine/threonine kinase, controls cytokine production by regulating transcription factors. The artificial in vitro activation of CD4⁺ T lymphocytes by a combination of 12-O-tetradecanoylphorbol-13-acetate and ionomycin, the so-called T/I model, led to an inducible production of cytokines, such as interferon-γ, tumor necrosis factor-α, and interleukin-2. As demonstrated by the approaches of pharmacological targeting and genetic knockdown of GSK-3β, T/I treatment effectively caused GSK-3β activation followed by GSK-3β-regulated cytokine production. In contrast, pharmacological inhibition of the proline-rich tyrosine kinase 2 and calcineurin signaling pathways blocked cytokine production, probably by deactivating GSK-3β. The blockade of GSK-3β led to the inhibition of the nuclear translocation of T-bet, a vital transcription factor of T lymphocyte cytokines. In a mouse model, treatment with the GSK-3β inhibitor 6-bromoindirubin-3’-oxime significantly inhibited T/I-induced mortality and serum cytokine levels. In summary, targeting GSK-3β effectively inhibits CD4⁺ T lymphocyte activation and cytokine production.

PTPN22 interacts with EB1 to regulate T-cell receptor signaling

The PTPN22 gene encoding the Lyp/Pep protein tyrosine phosphatase is a negative regulator of T-cell receptor (TCR) signaling. Recent studies have shown that phosphorylation of end-binding protein 1 (EB1) is associated with the TCR activation. In this study, using 2-hybrid and mass spectrometry analyses, we identified EB1 as a protein associated with PTPN22. Furthermore, we discovered that EB1 specifically bound to the P1 domain of PTPN22 by competing with CSK, and the variant PTPN22-R620W does not affect the association with EB1, which is instrumental with respect to the regulation of TCR signaling. In addition, PTPN22 dephosphorylates EB1 at tyrosine-247 (Y247), which decreases the expression of the T-cell activation markers CD25 and CD69 and the phosphorylation levels of the TCR molecules ZAP-70, LAT, and Erk, leading to the eventual downregulation of the transcription factor NFAT and reduced the levels of secreted IL-2. The findings of this study provide new insights into the TCR signaling and the T-cell immune response, which are important for clarifying the mechanism of PTPN22-related autoimmune diseases.

Cyclosporine Broadens the Therapeutic Potential of Lenalidomide in Myeloid Malignancies

The immunomodulatory drug lenalidomide is used for the treatment of certain hematologic malignancies, including myelodysplastic syndromes (MDS). Lenalidomide interacts with cereblon (CRBN), a component of the CRL4CRBN E3 ubiquitin ligase complex, leading to ubiquitination and subsequent degradation of substrates, such as transcription factor Ikaros (Ikaros family zinc finger 1, IKZF1). With a genome loss of function screen, we recently identified two novel pathways mediated by lenalidomide in MDS. In this review, we summarized the major findings of these two pathways and their clinical implications. Depletion of G protein-coupled receptor 68 (GPR68) or an endogenous calcineurin (CaN) inhibitor, regulator of calcineurin 1 (RCAN1), reversed the inhibitory effect of lenalidomide on MDSL cells, an MDS cell line. Intriguingly, both GPR68 and RCAN1 expression levels were upregulated in MDSL cells after treatment with lenalidomide that was dependent on diminishment of IKZF1, indicating that IKZF1 functioned as a transcription repressor for GPR68 and RCAN1. Mechanistic studies revealed that upregulation or activation of GPR68 induced a Ca2+/calpain pro-apoptotic pathway, while upregulation of RCAN1 inhibited the CaN pro-survival pathway in MDSL cells. Notably, the pharmacological CaN inhibitor, cyclosporine, enhanced the sensitivity to lenalidomide in MDS as well as acute myeloid leukemia (AML). Surprisingly, pretreatment with lenalidomide reversed the immunosuppressive effects of cyclosporine on T lymphocytes. Our studies suggest that lenalidomide mediates degradation of IKZF1, leading to derepression of GPR68 and RCAN1 that activates the Ca2+/calpain pro- apoptotic pathway and inhibits the CaN pro-survival pathway, respectively. Our studies implicate that cyclosporine extends the therapeutic potential of lenalidomide to myeloid malignancies without compromising immune function.

NFAT-Specific Inhibition by dNP2-VIVITAmeliorates Autoimmune Encephalomyelitisby Regulation of Th1 and Th17

Nuclear factor of activated T cells (NFATs) is an important transcription factor for T cell activation and proliferation. Recent studies have highlighted the role of NFATs in regulating the differentiation of effector CD4 T helper (Th) subsets including Th1 and Th17 cells. Because controlling the effector T cell function is important for the treatment of autoimmune diseases, regulation of NFAT functions in T cells would be an important strategy to control the pathogenesis of autoimmune diseases. Here, we demonstrated that an NFAT inhibitory peptide, VIVIT conjugated to dNP2 (dNP2-VIVIT), a blood-brain barrier-permeable peptide, ameliorated experimental autoimmune encephalomyelitis (EAE) by inhibiting Th1 and Th17 cells, but not regulatory T (T_reg) cells. dNP2-VIVIT negatively regulated spinal cord-infiltrating interleukin-17A (IL-17A) and interferon (IFN)-γ-producing CD4⁺ T cells without affecting the number of Foxp3⁺ CD4⁺ T_reg cells, whereas dNP2-VEET or 11R-VIVIT could not significantly inhibit EAE. In comparison with cyclosporin A (CsA), dNP2-VIVIT selectively inhibited Th1 and Th17 differentiation, whereas CsA inhibited the differentiation of all T cell subsets including that of Th2 and T_reg cells. Collectively, this study demonstrated the role of dNP2-VIVIT as a novel agent for the treatment of autoimmune diseases such as multiple sclerosis by regulating the functions of Th1 and Th17 cells.

Revisiting the Concept of Targeting NFAT to Control T Cell Immunity and Autoimmune Diseases

The nuclear factor of activated T cells (NFAT) family of transcription factors, which includes NFAT1, NFAT2, and NFAT4, are well-known to play important roles in T cell activation. Most of NFAT proteins are controlled by calcium influx upon T cell receptor and costimulatory signaling results increase of IL-2 and IL-2 receptor. NFAT3 however is not shown to be expressed in T cells and NFAT5 has not much highlighted in T cell functions yet. Recent studies demonstrate that the NFAT family proteins involve in function of lineage-specific transcription factors during differentiation of T helper 1 (Th1), Th2, Th17, regulatory T (Treg), and follicular helper T cells (Tfh). They have been studied to make physical interaction with the other transcription factors like GATA3 or Foxp3 and they also regulate Th cell signature gene expressions by direct binding on promotor region of target genes. From last decades, NFAT functions in T cells have been targeted to develop immune modulatory drugs for controlling T cell immunity in autoimmune diseases like cyclosporine A, FK506, etc. Due to their undesirable side defects, only limited application is available in human diseases. This review focuses on the recent advances in development of NFAT targeting drug as well as our understanding of each NFAT family protein in T cell biology. We also discuss updated detail molecular mechanism of NFAT functions in T cells, which would lead us to suggest an idea for developing specific NFAT inhibitors as a therapeutic drug for autoimmune diseases.

Adenosine and anergy

T cells must integrate multiple environmental cues when deciding whether to mount an immunogenic or tolerogenic response. Since not all self-reactive T cells are eliminated during thymic development, mechanisms of peripheral tolerance such as T cell anergy contribute to preventing autoimmunity. Recent studies have implicated extracellular adenosine and the adenosine A(2A) receptor as playing an important role in inhibiting T cell effector function. Herein, we review the current literature regarding T cell anergy and the emerging literature implicating the A(2A) receptor as critical regulator of immune activation. Finally, we present evidence to suggest a possible role for adenosine A(2A) receptor signaling in T cell anergy.

Opposing regulation of T cell function by Egr-1/NAB2 and Egr-2/Egr-3

TCR-induced NF-AT activation leads to the up-regulation of multiple genes involved in T cell anergy. Since NF-AT is also involved in T cell activation, we have endeavored to dissect TCR-induced activating and inhibitory genetic programs. This approach revealed roles for the early growth response (Egr) family of transcription factors and the Egr coactivator/corepressor NGFI-A-binding protein (NAB)2 in regulating T cell function. TCR-induced Egr-1 and NAB2 enhance T cell function, while Egr-2 and Egr-3 inhibit T cell function. In this report, we demonstrate that Egr-2 and Egr-3 are induced by NF-AT in the absence of AP-1, while Egr-1 and NAB2 both require AP-1-mediated transcription. Our data suggest that Egr-3 is upstream of Egr-2, and that mechanistically Egr-2 and Egr-3 suppress Egr-1 and NAB2 expression. Functionally, T cells from Egr-2 and Egr-3 null mice are hyperresponsive while T cells from Egr-3 transgenic, overexpressing mice are hyporesponsive. Furthermore, an in vivo model of autoimmune pneumonitis reveals that T cells from Egr-3 null mice hasten death while Egr-3-overexpressing T cells cause less disease. Overall, our data suggest that just as the Egr/NAB network of genes control cell fate in other systems, TCR-induced Egr-1, 2, 3 and NAB2 control the fate of antigen recognition in T cells.

Calcium-dependent expression of TNF-α in neural cells is mediated by the calcineurin/NFAT pathway

We report induction of TNF-alpha via the calcium/calcineurin/NFAT pathway in PC12 neural cells. In PC12, expression of TNF-alpha mRNA, protein and TNF-alpha gene promoter activity was induced by co-stimulation with phorbol ester and either calcium ionophore A23187 or the L-type Voltage Gated Calcium Channel agonist Bay K 8644. Pre-treatment with calcineurin inhibitors CsA or FK506 inhibited the dominant calcium-dependent component of this induction, limiting it to the level achieved with phorbol ester alone. Promoter activation by Bay was abolished by nifedipine, a specific inhibitor of L-type Voltage Gated Calcium Channels. Exogenous NFAT protein transactivated the TNF-alpha promoter, and the peptide VIVIT-a specific inhibitor of calcineurin/NFAT binding-blocked calcium-inducible transactivation of the TNF-alpha promoter. Given proposed functions of TNF-alpha in spatial learning, memory and the pathogenesis of neurodegenerative diseases, the data presented suggest an important role for calcineurin/NFAT signaling in these key neurological processes.

Immunomodulatory Drugs (IMiDs) Increase the Production of IL-2 from Stimulated T Cells by Increasing PKC-θ Activation and Enhancing the DNA-Binding Activity of AP-1 but Not NF-κB, OCT-1, or NF-AT

Immunomodulatory drugs (IMiDs) are orally available small molecules that potently inhibit tumor necrosis factor-alpha (TNF-alpha) production by lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (HuPBMCs) but enhance secretion of such cytokines as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) by stimulated T cells. The mechanism of cytokine regulation by IMiDs has not yet been determined. In the present study, we investigated the effects of one of the IMiDs, CC-4047 (Actimid, Celgene, Warren, NJ), on synthesis of IL-2 protein and mRNA and on the activity and expression of transcription factors. Treatment with CC-4047 enhances the secretion of IL-2 protein and the expression of IL-2 mRNA in a dose-dependent and time-dependent manner. In T cells stimulated with phorbol myristate acetate (PMA)/ionomycin, CC-4047 enhanced the DNA-binding activity of activated protein-1 (AP-1) but not NF-kappaB, Octomer-1 (OCT-1), or NFAT by 2-fold and 4-fold after an incubation time of 1 and 3 h, respectively. Luciferase reporter assays in Jurkat cells showed similar effects on transcription factor activity. Using in vitro kinase activity assays, we also showed that CC-4047 enhances the activity of protein kinase C-theta (PKC-theta) in stimulated T cells. The secreted IL-2 from HuPBMCs was shown to activate natural killer (NK) cells to lyse their target cell line K562. Taken together, our results demonstrate that the IMiDs exert their effects at least in part by activating PKC-theta and acting on AP-1 DNA-binding activity in T cells, resulting in augmented IL-2 synthesis and activation of IL- 2-dependent downstream effectors, such as NK cells.

Depolarization of neural cells induces transcription of the Down syndrome critical region 1 isoform 4 via a calcineurin/nuclear factor of activated T cells-dependent pathway

In this study we showed that the transcriptional regulation of Down syndrome critical region isoform 4 (DSCR1.4) is mediated by the calcineurin/nuclear factor of activated T cells (NFAT) pathway in neural cells. Stimuli that elicit an increase in the intracellular concentrations of calcium, such as membrane depolarization, induced de novo transcription of DSCR1.4, with mRNA expression peaking after 4 h and then declining. Action via the physiologically relevant L-type calcium channel was confirmed by blockade with nifedipine and verapamil. This calcium-dependent transcription of DSCR1.4 was inhibited by the calcineurin inhibitors cyclosporin A and FK506. Deletional analysis showed that the calcium- and calcineurin-dependent activation is mediated by the promoter region between nucleotides -350 and -166, a region that contains putative NFAT-binding motifs. Exogenous NFATc2 potently augmented the DSCR1.4 promoter transcriptional activity, and the involvement of endogenous NFAT signaling pathway in DSCR1.4 transcription was confirmed by the suppression of depolarization-inducible promoter activity with the NFAT inhibitor peptide VIVIT. Exogenous overexpression of DSCR1 protein (calcipressin 1) resulted in the inhibition of the transcription of DSCR1.4 and NFAT-dependent signaling. These findings suggest that calcineurin-dependent induction of DSCR1.4 product may represent an important auto-regulatory mechanism for the homeostatic control of NFAT signaling in neural cells.

Cells as vehicles for cancer gene therapy: the missing link between targeted vectors and systemic delivery?

Systemic administration of currently manufactured viral stocks has not so far achieved sufficient circulating titers to allow therapeutic targeting of metastatic disease. This is due to low initial viral titers, immune inactivation, nonspecific adhesion, and loss of particles. One way to exploit the elegant molecular manipulations that have been made to increase vector targeting is to protect these vectors until they reach the local sites of tumor growth. Various cell types home preferentially to tumors and can be loaded with the constructs required to produce targeted vectors. Here we discuss the potential of using such cell carriers to chaperone precious vectors directly to the tumors. The vectors can incorporate mechanisms to achieve tumor site-inducible expression, along with tumor cell-specific expression of the therapeutic gene and/or replicating viral genomes that would be released at the tumor. In this way, the great advances that have so far been made with the engineering of vector tropisms might be genuinely exploited and converted into clinical benefit.

Nonsteroidal anti-inflammatory drugs prevent early diabetic retinopathy via TNF-alpha suppression

Leukocyte adhesion to the diabetic retinal vasculature results in blood-retinal barrier breakdown, capillary nonperfusion, and endothelial cell injury and death. Intercellular adhesion molecule-1 (ICAM-1) and the leukocyte integrin CD18 are required for these processes. Diabetes was induced in Long Evans rats, resulting in a two- to threefold increase in retinal leukocyte adhesion. Following one week of diabetes, neutrophil CD11a, CD11b, and CD18 expression was increased significantly, as were retinal ICAM-1 levels. Animals were treated with aspirin, a cyclooxygenase 2 (COX-2) inhibitor (meloxicam), or a soluble tumor necrosis factor alpha (TNF-alpha) receptor/Fc construct (TNFR-Fc, etanercept). High-dose aspirin, etanercept, and high-dose meloxicam each reduced leukocyte adhesion and suppressed blood-retinal barrier breakdown. High-dose aspirin also reduced the expression of CD11a, CD11b, and CD18, whereas meloxicam and etanercept did not. High-dose aspirin, etanercept, and high-dose meloxicam each reduced retinal ICAM-1 expression. Aspirin and meloxicam both lowered retinal TNF-alpha levels. Notably, aspirin, meloxicam, and etanercept did not change retinal vascular endothelial growth factor levels. High-dose aspirin, etanercept and high-dose meloxicam, each suppressed the retinal expression of eNOS and the DNA-binding capacity of retinal nuclear factor-kappaB. High-dose aspirin also suppressed Erk kinase activity, which is involved in CD18 up-regulation. Taken together, these data identify COX-2 and TNF-alpha as operative in the early signature pathologies of diabetic retinopathy, a newly recognized inflammatory disease.

Bridging the NFAT and NF-kappaB families: NFAT5 dimerization regulates cytokine gene transcription in response to osmotic stress

The transcription factor NFAT5/TonEBP is evolutionarily the oldest member of the NFAT/Rel family of transcription factors. We show that NFAT5 is uniquely related to NF-kappaB and is the only member of the Rel/NFAT family to be activated by osmotic stress. Like Rel/NF-kappaB proteins but unlike the calcium-regulated NFAT proteins, NFAT5 is constitutively dimeric, and dimerization is essential for DNA binding and transcriptional activity. Using dominant-negative proteins that inhibit NFAT5 dimerization, we show that NFAT5 regulates expression of the TNFalpha and lymphotoxin-beta genes in osmotically stressed T cells. Chromatin immunoprecipitation experiments confirm that NFAT5 binds to the TNFalpha promoter in vivo. We suggest that NFAT5 participates in specific aspects of host defense by upregulating TNF family genes and other target genes in T cells.