NFAT1 transcription factor is central in the regulation of tissue microenvironment for tumor metastasis

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.

Alterations of Growth and Focal Adhesion Molecules in Human Breast Cancer Cells Exposed to the Random Positioning Machine

In this study, we evaluated changes in focal adhesions (FAs) in two types of breast cancer cell (BCC) lines (differentiated MCF-7 and the triple-negative MDA-MB-231 cell line) exposed to simulated microgravity (s-μg) created by a random positioning machine (RPM) for 24 h. After exposure, the BCC changed their growth behavior and exhibited two phenotypes in RPM samples: one portion of the cells grew as a normal two-dimensional monolayer [adherent (AD) BCC], while the other portion formed three-dimensional (3D) multicellular spheroids (MCS). After 1 h and 30 min (MDA-MB-231) and 1 h 40 min (MCF-7), the MCS adhered completely to the slide flask bottom. After 2 h, MDA-MB-231 MCS cells started to migrate, and after 6 h, a large number of the cells had left the MCS and continued to grow in a scattered pattern, whereas MCF-7 cells were growing as a confluent monolayer after 6 h and 24 h. We investigated the genes associated with the cytoskeleton, the extracellular matrix and FAs. ACTB, TUBB, FN1, FAK1, and PXN gene expression patterns were not significantly changed in MDA-MB-231 cells, but we observed a down-regulation of LAMA3, ITGB1 mRNAs in AD cells and of ITGB1, TLN1 and VCL mRNAs in MDA-MB-231 MCS. RPM-exposed MCF-7 cells revealed a down-regulation in the gene expression of FAK1, PXN, TLN1, VCL and CDH1 in AD cells and PXN, TLN and CDH1 in MCS. An interaction analysis of the examined genes involved in 3D growth and adhesion indicated a central role of fibronectin, vinculin, and E-cadherin. Live cell imaging of eGFP-vinculin in MCF-7 cells confirmed these findings. β-catenin-transfected MCF-7 cells revealed a nuclear expression in 1g and RPM-AD cells. The target genes BCL9, MYC and JUN of the Wnt/β-catenin signaling pathway were differentially expressed in RPM-exposed MCF-7 cells. These findings suggest that vinculin and β-catenin are key mediators of BCC to form MCS during 24 h of RPM-exposure.

OSW-1 inhibits tumor growth and metastasis by NFATc2 on triple-negative breast cancer

OSW‐1 is a natural compound extracted from the bulbs of Ornithogalum saundersiae in 1992. It has been shown strong antitumor activities in various cancer cells. However, the effects of OSW‐1 on tumor growth and metastasis in breast cancer are still poorly understood. In our research, we showed that OSW‐1 had a strong anticancer effect on breast cancer cells, but lower toxicity to normal cells. Accordingly, it also revealed significant inhibition of tumor growth by OSW‐1 in xenograft model. In addition, we performed Annexin V/PI‐labeled flow cytometric assay and TUNEL assay and showed that OSW‐1 inhibited tumor growth by inducing apoptosis. Furthermore, we carried out transwell assays and found that OSW‐1 significantly repressed the migratory and invasive capabilities of triple‐negative breast cancer (TNBC) cells via mediating epithelial‐mesenchymal transition. Besides, OSW‐1 also could inhibit metastasis in an orthotopic model and resulted in a longer survival compared with control group. Finally, we performed RNA‐sequencing and cellular functions to investigate the molecular mechanism of how OSW‐1 inhibits TNBC, and identified NFATc2 may as a pivotal factor for OSW‐1‐mediated effects on cell death, tumor growth, invasion, and migration.

Multifaceted Role of the Placental Growth Factor (PlGF) in the Antitumor Immune Response and Cancer Progression

The sharing of molecules function that affects both tumor growth and neoangiogenesis with cells of the immune system creates a mutual interplay that impairs the host’s immune response against tumor progression. Increasing evidence shows that tumors are able to create an immunosuppressive microenvironment by recruiting specific immune cells. Moreover, molecules produced by tumor and inflammatory cells in the tumor microenvironment create an immunosuppressive milieu able to inhibit the development of an efficient immune response against cancer cells and thus fostering tumor growth and progression. In addition, the immunoediting could select cancer cells that are less immunogenic or more resistant to lysis. In this review, we summarize recent findings regarding the immunomodulatory effects and cancer progression of the angiogenic growth factor namely placental growth factor (PlGF) and address the biological complex effects of this cytokine. Different pathways of the innate and adaptive immune response in which, directly or indirectly, PlGF is involved in promoting tumor immune escape and metastasis will be described. PlGF is important for building up vascular structures and functions. Although PlGF effects on vascular and tumor growth have been widely summarized, its functions in modulating the immune intra-tumoral microenvironment have been less highlighted. In agreement with PlGF functions, different antitumor strategies can be envisioned.

Dose-Dependent Sorafenib-Induced Immunosuppression Is Associated with Aberrant NFAT Activation and Expression of PD-1 in T Cells

The multikinase inhibitor sorafenib is the only standard first-line therapy for hepatocellular carcinoma (HCC). Here, we report the dose-dependent effects of sorafenib on the immune response, which is related to nuclear factor of activated T cells 1 (NFAT1) activity. In vitro and in vivo experiments were performed with low and high doses of sorafenib using human T cells and spontaneous developed woodchuck HCC models. In vitro studies demonstrated that following exposure to a high dose of sorafenib the baseline activity of NFAT1 in T cells was significantly increased. In a parallel event, high dose sorafenib resulted in a significant decrease in T cell proliferation and increased the proportion of PD-1 expressing CD8+ T cells with NFAT1 activation. In the in vivo model, smaller tumors were detected in the low-dose sorafenib treated group compared to the placebo and high-dose treated groups. The low-dose sorafenib group showed a significant tumor growth delay with significantly more CD3+ cells in tumor. This study demonstrates that sorafenib has immunomodulatory effects in a dose- and time-dependent manner. Higher dose of sorafenib treatment was associated with immunosuppressive action. This observed effect of sorafenib should be taken into consideration in the selection of optimum starting dose for future trials.

NFAT1 enhances the effects of tumor-associated macrophages on promoting malignant melanoma growth and metastasis

Tumor-associated macrophages (TAMs) play substantial roles in tumor growth, invasion, and metastasis. Nuclear factor of activated T cell (NFAT1) has been shown to promote melanoma growth and metastasis in vivo We herein aim to investigate whether NFAT1 is capable to promote melanoma growth and metastasis by influencing TAM properties. Melanoma-conditioned TAMs were obtained from human monocytes after incubation with conditioned medium from A375 cell culture. The phenotype of the macrophages was detected. Cell proliferation, migration, and invasion were evaluated. Human malignant melanoma tissues exhibited increased CD68+-macrophage infiltration and NFAT1 expression compared with the normal pigmented nevus tissues. Melanoma-conditioned TAMs displayed M2-like phenotype. Melanoma-conditioned TAMs also promoted proliferation, migration, and invasion of human malignant melanoma cell lines A375 and WM451. Furthermore, NFAT1 expression in TAMs was significantly increased compared with the M0 group. NFAT1 overexpression significantly strengthened the melanoma-conditioned TAM-mediated promotion of cell migration and invasion in A375 and WM451 cells, whereas NFAT1 knockdown exerted the opposite effects. Moreover, NFAT1 overexpression in melanoma-conditioned TAMs promoted CD68+-macrophage infiltration, tumor growth, and metastasis in vivo NFAT1 may play a critical role in enhancing the TAM-mediated promotion of growth and metastasis in malignant melanoma.

NFATc2 enhances tumor-initiating phenotypes through the NFATc2/SOX2/ALDH axis in lung adenocarcinoma

Tumor-initiating cells (TIC) are dynamic cancer cell subsets that display enhanced tumor functions and resilience to treatment but the mechanism of TIC induction or maintenance in lung cancer is not fully understood. In this study, we show the calcium pathway transcription factor NFATc2 is a novel regulator of lung TIC phenotypes, including tumorspheres, cell motility, tumorigenesis, as well as in vitro and in vivo responses to chemotherapy and targeted therapy. In human lung cancers, high NFATc2 expression predicted poor tumor differentiation, adverse recurrence-free and cancer-specific overall survivals. Mechanistic investigations identified NFATc2 response elements in the 3’ enhancer region of SOX2, and NFATc2/SOX2 coupling upregulates ALDH1A1 by binding to its 5’ enhancer. Through this axis, oxidative stress induced by cancer drug treatment is attenuated, leading to increased resistance in a mutation-independent manner. Targeting this axis provides a novel approach for the long-term treatment of lung cancer through TIC elimination.

DOI:http://dx.doi.org/10.7554/eLife.26733.001

Cancer develops when cells become faulty and start to grow uncontrollably. They eventually form lumps or tumors, which may spread to surrounding tissues or even to other areas in the body. One of the reasons why cancer treatment remains a challenge is that there are over 200 types of cells in the body, and there are a lot of moments in the life cycle of a cell when things could go wrong. Researchers have shown that many cancers, including lung cancer, are not only extremely different from patient to patient, but also display great differences between cancer cells within the same tumor.

Increasing evidence suggest that these differences may be caused by a type of cells called tumor initiating cells, or TICs for short. These TICs behave like stem cells and can renew themselves or mature into different types of cells. They are thought to help cancers grow and spread, and even make them resistant to treatments. Previous research has shown that in many types of cancer, the protein NFATc2 helps cancer cells to grow and spread. Until now, however, it was not known if NFATc2 is also important in TICs in lung cancer.

Using human lung cancer cell lines and animal models, Xiao et al. show that the protein NFATc2 stimulates the stem-cell like behavior of TICs. The results showed that TICs had higher levels of the NFATc2 protein than other lung cancer cells that were not TICs. Tumors with higher levels were also more aggressive. When NFATc2 was removed from the cells, they formed smaller tumors and were more sensitive to drug treatment compared to cancer cells with NFATc2.

Further experiments revealed that NFATc2 helped to increase the levels of a protein called Sox2, which gives cells the ability to renew or develop into different cell types. Together, these two proteins stimulated the production of another protein that was already known to play a crucial role in TIC maintenance.

A better understanding of the mechanisms regulating TICs in lung cancer will help scientists tackle new questions about how this cancer progresses and resists to therapy. In the longer-term, combining classic cancer treatments with new therapeutic strategies targeting NFATc2 could make treatments for lung cancer patients more effective.

DOI:http://dx.doi.org/10.7554/eLife.26733.002

Regulation of CacyBP/SIP expression by NFAT1 transcription factor

In this work we have shown that NFAT1 transcription factor is involved in the regulation of CacyBP/SIP expression. We have demonstrated, by applying Western blot, RT-PCR and luciferase assay that the level of CacyBP/SIP increases upon NFAT1 overexpression. Moreover, inhibition or stimulation of NFAT transcriptional activity exerts a corresponding effect on the expression of CacyBP/SIP gene. Furthermore, EMSA and chromatin immunoprecipitation (ChIP) assay have shown that NFAT1 binds to its specific binding sites within the CacyBP/SIP gene. In conclusion, our data have shown for the first time the regulation of CacyBP/SIP gene expression by NFAT1. Since NFAT transcription factors are involved in processes related to immune response, these results indicate potential involvement of CacyBP/SIP in the immune system.

NFAT1 Directly Regulates IL8 and MMP3 to Promote Melanoma Tumor Growth and Metastasis

Nuclear factor of activated T cell (NFAT1, NFATC2) is a transcription factor that binds and positively regulates IL2 expression during T-cell activation. NFAT1 has important roles in both innate and adaptive immune responses, but its involvement in cancer is not completely understood. We previously demonstrated that NFAT1 contributes to melanoma growth and metastasis by regulating the autotaxin gene (Enpp2). Here, we report a strong correlation between NFAT1 expression and metastatic potential in melanoma cell lines and tumor specimens. To elucidate the mechanisms underlying NFAT1 overexpression during melanoma progression, we conducted a microarray on a highly metastatic melanoma cell line in which NFAT1 expression was stably silenced. We identified and validated two downstream targets of NFAT1, IL8, and MMP3. Accordingly, NFAT1 depletion in metastatic melanoma cell lines was associated with reduced IL8 and MMP3 expression, whereas NFAT1 overexpression in a weakly metastatic cell line induced expression of these targets. Restoration of NFAT1 expression recovered IL8 and MMP3 expression levels back to baseline, indicating that both are direct targets of NFAT1. Moreover, in vivo studies demonstrated that NFAT1 and MMP3 promoted melanoma tumor growth and lung metastasis. Collectively, our findings assign a new role for NFAT1 in melanoma progression, underscoring the multifaceted functions that immunomodulatory factors may acquire in an unpredictable tumor microenvironment. Cancer Res; 76(11); 3145-55. ©2016 AACR.

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.

NFAT as cancer target: mission possible?

The NFAT signaling pathway regulates various aspects of cellular functions; NFAT acts as a calcium sensor, integrating calcium signaling with other pathways involved in development and growth, immune response, and inflammatory response. The NFAT family of transcription factors regulates diverse cellular functions such as cell survival, proliferation, migration, invasion, and angiogenesis. The NFAT isoforms are constitutively activated and overexpressed in several cancer types wherein they transactivate downstream targets that play important roles in cancer development and progression. Though the NFAT family has been conclusively proved to be pivotal in cancer progression, the different isoforms play distinct roles in different cellular contexts. In this review, our discussion is focused on the mechanisms that drive the activation of various NFAT isoforms in cancer. Additionally, we analyze the potential of NFAT as a valid target for cancer prevention and therapy.

Nfatc2 and Tob1 have non-overlapping function in T cell negative regulation and tumorigenesis

Nfatc2 and Tob1 are intrinsic negative regulators of T cell activation. Nfatc2-deficient and Tob1-deficient T cells show reduced thresholds of activation; however, whether these factors have independent or overlapping roles in negative regulation of T cell responses has not been previously examined. Here, we show that Nfatc2 knockout (KO) but not Tob1 KO mice have age-associated accumulation of persistently activated T cells in vivo and expansion of the CD44+ memory cell compartment and age-associated lymphocytic infiltrates in visceral organs, without significant changes in numbers of CD4+CD25+Foxp3+ regulatory T cells (Treg). In vitro, CD4+CD25- "conventional" T cells (Tconvs) from both KO strains showed greater proliferation than wild type (WT) Tconvs. However, while Tregs from Nfatc2 KO mice retained normal suppressive function, Tregs from Tob1 KOs had enhanced suppressive activity. Nfatc2 KO Tconvs expanded somewhat more rapidly than WT Tconvs under conditions of homeostatic proliferation, but their accelerated growth capacity was negated, at least acutely, in a lymphoreplete environment. Finally, Nfatc2 KO mice developed a previously uncharacterized increase in B-cell malignancies, which was not accelerated by the absence of Tob1. The data thus support the prevailing hypothesis that Nfatc2 and Tob1 are non-redundant regulators of lymphocyte homeostasis.

The role of the dysfunctional akt-related pathway in cancer: establishment and maintenance of a malignant cell phenotype, resistance to therapy, and future strategies for drug development

Akt serine/threonine kinases, or PKB, are key players in the regulation of a wide variety of cellular activities, such as growth, proliferation, protection from apoptotic injuries, control of DNA damage responses and genome stability, metabolism, migration, and angiogenesis. The Akt-related pathway responds to the stimulation mediated by growth factors, cytokines, hormones, and several nutrients. Akt is present in three isoforms: Akt1, Akt2, and Akt3, which may be alternatively named PKB α , PKB β , and PKB γ , respectively. The Akt isoforms are encoded on three diverse chromosomes and their biological functions are predominantly distinct. Deregulations in the Akt-related pathway were observed in many human maladies, including cancer, cardiopathies, neurological diseases, and type-2 diabetes. This review discusses the significance of the abnormal activities of the Akt axis in promoting and sustaining malignancies, along with the development of tumor cell populations that exhibit enhanced resistance to chemo- and/or radiotherapy. This occurrence may be responsible for the relapse of the disease, which is unfortunately very often related to fatal consequences in patients.

NFAT gene family in inflammation and cancer

Calcineurin-NFAT signaling is critical for numerous aspects of vertebrate function during and after embryonic development. Initially discovered in T cells, the NFAT gene family, consisting of five members, regulates immune system, inflammatory response, angiogenesis, cardiac valve formation, myocardial development, axonal guidance, skeletal muscle development, bone homeostasis, development and metastasis of cancer, and many other biological processes. In this review we will focus on the NFAT literature relevant to the two closely related pathological systems: inflammation and cancer.

A single extra copy of Dscr1 improves survival of mice developing spontaneous lung tumors through suppression of tumor angiogenesis

The incidence of most solid tumors is remarkably reduced in individuals with Down syndrome. Using mouse models of Down syndrome, we have previously shown that this decrease in tumor incidence is due, in part, to suppression of tumor angiogenesis as a consequence of attenuated calcineurin signaling in endothelial cells. Our prior studies utilized xenografted tumors in a transgenic mouse model with three copies of the Down syndrome critical region-1 (Dscr1) gene, a chromosome 21-encoded endogenous calcineurin inhibitor. These data indicate that upregulated Dscr1 contributes to broad cancer protection by suppressing tumor angiogenesis through inhibiting the calcineurin pathway in the vascular endothelium. However, it still remains to be confirmed whether a single extra copy of Dscr1 is also sufficient to suppress tumor angiogenesis in slow growing spontaneous tumors that more accurately recapitulate molecular features of human malignancies. In this study, utilizing LSL-Kras(G12D) mice, an inducible and autochthonous model of human lung adenocarcinoma, on a Dscr1 transgenic mouse background, we show that a single extra transgenic copy of Dscr1 provides a survival advantage in these mice developing spontaneous lung tumors driven by oncogenic Kras(G12D) without affecting either initiation or progression of spontaneous lung tumors. Furthermore, we show that Dscr1 trisomy significantly reduces microvessel density in lung tumors and thus limits the growth of lung tumors through decreased proliferation and increased apoptosis of lung tumor cells. These data provide evidence that a single extra copy of Dscr1 is sufficient to suppress tumor angiogenesis during spontaneous lung tumorigenesis and further support our hypothesis that suppression of tumor angiogenesis by an additional copy of Dscr1 contributes to the reduced cancer incidence in individuals with Down syndrome and the calcineurin pathway in the tumor vasculature is a potential target for cancer treatment.

Nuclear factor of activated T cells - a transcription factor family as critical regulator in lung and colon cancer

Nuclear factor of activated T cells (NFAT) was first identified as a transcription factor which is activated upon T cell stimulation. Subsequent studies uncovered that a whole family of individual NFAT proteins exists with pleiotropic functions not only in immune but also in nonimmune cells. However, dysregulation of NFAT thereby favors malignant growth and cancer. Summarizing the recent advances in understanding how individual NFAT factors regulate the immune system, this review gives new insights into the critical role of NFAT in cancer development with special focus on inflammation-associated colorectal cancer.

Galectin-3 contributes to melanoma growth and metastasis via regulation of NFAT1 and autotaxin

Melanoma is the deadliest form of skin cancer in which patients with metastatic disease have a 5-year survival rate of less than 10%. Recently, the overexpression of a β-galactoside binding protein, galectin-3 (LGALS3), has been correlated with metastatic melanoma in patients. We have previously shown that silencing galectin-3 in metastatic melanoma cells reduces tumor growth and metastasis. Gene expression profiling identified the protumorigenic gene autotaxin (ENPP2) to be downregulated after silencing galectin-3. Here we report that galectin-3 regulates autotaxin expression at the transcriptional level by modulating the expression of the transcription factor NFAT1 (NFATC2). Silencing galectin-3 reduced NFAT1 protein expression, which resulted in decreased autotaxin expression and activity. Reexpression of autotaxin in galectin-3 silenced melanoma cells rescues angiogenesis, tumor growth, and metastasis in vivo. Silencing NFAT1 expression in metastatic melanoma cells inhibited tumor growth and metastatic capabilities in vivo. Our data elucidate a previously unidentified mechanism by which galectin-3 regulates autotaxin and assign a novel role for NFAT1 during melanoma progression.

NFAT1 supports tumor-induced anergy of CD4(+) T cells

Cancer cells express antigens that elicit T cell-mediated responses, but these responses are limited during malignant progression by the development of immunosuppressive mechanisms in the tumor microenvironment that drive immune escape. T-cell hyporesponsiveness can be caused by clonal anergy or adaptive tolerance, but the pathophysiological roles of these processes in specific tumor contexts has yet to be understood. In CD4+ T cells, clonal anergy occurs when the T-cell receptor is activated in the absence of a costimulatory signal. Here we report that the key T-cell transcription factor NFAT mediates expression of anergy-associated genes in the context of cancer. Specifically, in a murine model of melanoma, we found that cancer cells induced anergy in antigen-specific CD4+ T-cell populations, resulting in defective production of several key effector cytokines. NFAT1 deficiency blunted the induction of anergy in tumor antigen-specific CD4+ T cells, enhancing antitumor responses. These investigations identified tumor-induced T-cell hyporesponsiveness as a form of clonal anergy, and they supported an important role for CD4+ T-cell anergy in driving immune escape. By illustrating the dependence of tumor-induced CD4+ T-cell anergy on NFAT1, our findings open the possibility of targeting this transcription factor to improve the efficacy of cancer immunotherapy or immunochemotherapy.