STAT4

Gene Summary

Gene:STAT4; signal transducer and activator of transcription 4
Aliases: SLEB11
Location:2q32.2-q32.3
Summary:The protein encoded by this gene is a member of the STAT family of transcription factors. In response to cytokines and growth factors, STAT family members are phosphorylated by the receptor associated kinases, and then form homo- or heterodimers that translocate to the cell nucleus where they act as transcription activators. This protein is essential for mediating responses to IL12 in lymphocytes, and regulating the differentiation of T helper cells. Mutations in this gene may be associated with systemic lupus erythematosus and rheumatoid arthritis. Alternate splicing results in multiple transcript variants that encode the same protein. [provided by RefSeq, Aug 2011]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:signal transducer and activator of transcription 4
HPRD
Source:NCBIAccessed: 25 June, 2015

Ontology:

What does this gene/protein do?
Show (13)
Pathways:What pathways are this gene/protein implicaed in?
Show (3)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 25 June 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Genotype
  • Genetic Predisposition
  • T-Lymphocytes
  • Th2 Cells
  • Base Sequence
  • Apoptosis
  • Genome-Wide Association Study
  • Transcription
  • Interferon-gamma
  • Leukemic Gene Expression Regulation
  • Transcription Factors
  • Cancer Gene Expression Regulation
  • TYK2 Kinase
  • Chromosome 2
  • Lymphoma
  • Phosphorylation
  • Signal Transduction
  • Tissue Array Analysis
  • DNA-Binding Proteins
  • Skin Cancer
  • Interleukin-12
  • Gene Expression
  • STAT1 Transcription Factor
  • Hepatocellular Carcinoma
  • Natural Killer Cells
  • Tumor Markers
  • Sezary Syndrome
  • Oligonucleotide Array Sequence Analysis
  • Case-Control Studies
  • Ubiquitin
  • Twist Transcription Factor
  • STAT4 Transcription Factor
  • Gene Expression Profiling
  • TNF
  • Th1 Cells
  • Liver Cancer
  • RTPCR
  • Single Nucleotide Polymorphism
  • Trans-Activators
  • Neoplastic Cell Transformation
Tag cloud generated 25 June, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: STAT4 (cancer-related)

Chen W, Wang M, Zhang Z, et al.
Replication the association of 2q32.2-q32.3 and 14q32.11 with hepatocellular carcinoma.
Gene. 2015; 561(1):63-7 [PubMed] Related Publications
Hepatocellular carcinoma (HCC) is a malignant tumor. The morbidity and mortality of HCC tend to ascend and become a serious threat to the population health. Genetic studies of HCC have identified several susceptibility loci of HCC. In this study, we aim to replicate the association of these loci in our samples from Chinese population and further investigate the genetic interaction. We selected 16 SNPs within 1p36.22, 2q32.2-q32.3, 3p21.33, 8p12, 14q32.11 and 21q21.3 and genotyped in 507 HCC patients and 3014 controls by using Sequenom MassARRAY system. Association analyses were performed by using PLINK 1.07. We observed that the STAT4 (2q32.2-q32.3) at rs7574865 (P=1.17×10(-3), OR=0.79) and EFCAB11 (14q32.11) at rs8013403 (P=1.54×10(-3), OR=0.80) were significantly associated with HCC in this study. In 3p21.33, genetic variant rs6795737 within GLB1 was also observed with suggestive evidence (P=9.98×10(-3), OR=0.84). In the interaction analysis, the pair of associated SNPs (rs7574865 within STAT4, rs8013403 within EFCAB11) generated evidence for interaction (P=4.10×10(-3)). In summary, our work first reported the association of 14q32.11 (EFCAB11) with HCC in Chinese Han population and revealed the genetic interaction between STAT4 (2q32.2-q32.3) and EFCAB11 (14q32.11) in HCC.

Zhao D, Long XD, Lu TF, et al.
Metformin decreases IL-22 secretion to suppress tumor growth in an orthotopic mouse model of hepatocellular carcinoma.
Int J Cancer. 2015; 136(11):2556-65 [PubMed] Related Publications
Epidemiological, preclinical and cellular studies in the last 5 years have shown that metformin exerts anti-tumoral properties, but its mode of action in cancer remains unclear. Here, we investigated the effects of metformin on a mouse hepatocellular carcinoma (HCC) model and tumor-associated T cell immune responses. Oral metformin administration led to a significant reduction of tumor growth, which was accompanied by decreased interleukin-22 (IL-22). Meanwhile, IL-22-induced STAT3 phosphorylation and upregulation of downstream genes Bcl-2 and cyclin D1 were inhibited by metformin. At the cellular level, metformin attenuated Th1- and Th17-derived IL-22 production. Furthermore, metformin inhibited de novo generation of Th1 and Th17 cells from naive CD4(+) cells. These observations were further supported by the fact that metformin treatment inhibited CD3/CD28-induced IFN-γ and IL-17A expression along with the transcription factors that drive their expression (T-bet [Th1] and ROR-γt [Th17], respectively). The effects of metformin on T cell differentiation were mediated by downregulated STAT3 and STAT4 phosphorylation via the AMP-activated kinase-mammalian target of rapamycin complex 1 pathway. Notably, metformin led to a reduction in glucose transporter Glut1 expression, resulting in less glucose uptake, which is critical to regulate CD4(+) T cell fate. Taken together, these findings provide evidence for the growth-inhibitory and immune-modulatory effects of metformin in HCC and thus, broaden our understanding about the action of metformin in liver cancer treatment.

Zhou X, Xia Y, Su J, Zhang G
Down-regulation of miR-141 induced by helicobacter pylori promotes the invasion of gastric cancer by targeting STAT4.
Cell Physiol Biochem. 2014; 33(4):1003-12 [PubMed] Related Publications
BACKGROUND: The association between Helicobacter pylori infection and gastric cancer has been identified recently. However, the molecular mechanism remained largely unknown.
METHODS AND RESULTS: We found that miR-141 was decreased in Helicobacter pylori positive specimens (n=75) compared with negative tissues (n=75). The knockdown of miR-141 enhanced the invasion ability of gastric cancer cells; meanwhile, over-expression of miR-141 could inhibit the abilities of gastric cancer cells in vitro. A luciferase assay revealed that miR-141 was directly bound to the 3'-untranslated regions (3'-UTR) of STAT4. STAT4 was found up-regulated at mRNA and protein levels, as shown by qRT-PCR and western blot. Over-expression of STAT4 was used to mimic miR-141 action in the invasion of gastric cancer.
CONCLUSION: MiR-141 may play a pivotal role in controlling gastric cancer invasion through regulating STAT4 and maybe a potential target to treat gastric cancer.

Chang HC, Lewis D, Tung CY, et al.
Soypeptide lunasin in cytokine immunotherapy for lymphoma.
Cancer Immunol Immunother. 2014; 63(3):283-95 [PubMed] Free Access to Full Article Related Publications
Immunostimulatory cytokines can enhance anti-tumor immunity and are part of the therapeutic armamentarium for cancer treatment. We have previously reported that post-transplant lymphoma patients have an acquired deficiency of signal transducer and activator of transcription 4, which results in defective IFNγ production during clinical immunotherapy. With the goal of further improving cytokine-based immunotherapy, we examined the effects of a soybean peptide called lunasin that synergistically works with cytokines on natural killer (NK) cells. Peripheral blood mononuclear cells of healthy donors and post-transplant lymphoma patients were stimulated with or without lunasin in the presence of IL-12 or IL-2. NK activation was evaluated, and its tumoricidal activity was assessed using in vitro and in vivo tumor models. Chromatin immunoprecipitation assay was performed to evaluate the histone modification of gene loci that are regulated by lunasin and cytokine. Adding lunasin to IL-12- or IL-2-stimulated NK cells demonstrated synergistic effects in the induction of IFNG and GZMB involved in cytotoxicity. The combination of lunasin and cytokines (IL-12 plus IL-2) was capable of restoring IFNγ production by NK cells from post-transplant lymphoma patients. In addition, NK cells stimulated with lunasin plus cytokines displayed higher tumoricidal activity than those stimulated with cytokines alone using in vitro and in vivo tumor models. The underlying mechanism responsible for the effects of lunasin on NK cells is likely due to epigenetic modulation on target gene loci. Lunasin represents a different class of immune modulating agent that may augment the therapeutic responses mediated by cytokine-based immunotherapy.

Dulmage BO, Geskin LJ
Lessons learned from gene expression profiling of cutaneous T-cell lymphoma.
Br J Dermatol. 2013; 169(6):1188-97 [PubMed] Free Access to Full Article Related Publications
Gene expression studies of cutaneous T-cell lymphoma (CTCL) span a decade, yet the pathogenesis is poorly understood and diagnosis remains a challenge. This review examines the varied approaches to gene expression analysis of CTCL, with emphasis on cell populations, control selection and expression data collection. Despite discordant results, several dysregulated genes have been identified across multiple studies, including PLS3, KIR3DL2, TWIST1 and STAT4. Here, we provide an overview of the most consistently expressed genes across different studies and bring them together through common pathways biologically relevant to CTCL. Four pathways - evasion of activation-induced cell death, T helper 2 lymphocyte differentiation, transforming growth factor-β receptor expression, and tumour necrosis factor receptor ligands - appear to encompass the most frequently affected genes, hypothetically providing insight into the disease pathogenesis.

Chen Y, Lan Q, Zheng T, et al.
Polymorphisms in JAK/STAT signaling pathway genes and risk of non-Hodgkin lymphoma.
Leuk Res. 2013; 37(9):1120-4 [PubMed] Free Access to Full Article Related Publications
Impaired function of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway genes leads to immunodeficiency and various hematopoietic disorders. We evaluated the association between genetic polymorphisms (SNPs) in 12 JAK/STAT pathway genes (JAK3, STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b, STAT6, SCOS1, SCOS2, SCOS3, and SCOS4) and NHL risk in a population-based case-control study of Connecticut women. We identified three SNPs in STAT3 (rs12949918 and rs6503695) and STAT4 (rs932169) associated with NHL risk after adjustment for multiple comparison. Our results suggest that genetic variation in JAK/STAT pathway genes may play a role in lymphomagenesis and warrants further investigation.

Jiang DK, Sun J, Cao G, et al.
Genetic variants in STAT4 and HLA-DQ genes confer risk of hepatitis B virus-related hepatocellular carcinoma.
Nat Genet. 2013; 45(1):72-5 [PubMed] Free Access to Full Article Related Publications
To identify genetic susceptibility loci for hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) in the Chinese population, we carried out a genome-wide association study (GWAS) in 2,514 chronic HBV carriers (1,161 HCC cases and 1,353 controls) followed by a 2-stage validation among 6 independent populations of chronic HBV carriers (4,319 cases and 4,966 controls). The joint analyses showed that HCC risk was significantly associated with two independent loci: rs7574865 at STAT4, P(meta) = 2.48 × 10(-10), odds ratio (OR) = 1.21; and rs9275319 at HLA-DQ, P(meta) = 2.72 × 10(-17), OR = 1.49. The risk allele G at rs7574865 was significantly associated with lower mRNA levels of STAT4 in both the HCC tissues and nontumor tissues of 155 individuals with HBV-related HCC (P(trend) = 0.0008 and 0.0002, respectively). We also found significantly lower mRNA expression of STAT4 in HCC tumor tissues compared with paired adjacent nontumor tissues (P = 2.33 × 10(-14)).

Liu S, Li L, Zhang Y, et al.
The oncoprotein HBXIP uses two pathways to up-regulate S100A4 in promotion of growth and migration of breast cancer cells.
J Biol Chem. 2012; 287(36):30228-39 [PubMed] Free Access to Full Article Related Publications
We have reported that hepatitis B X-interacting protein (HBXIP) promotes the proliferation and migration of breast cancer cells. However, the underlying mechanism is poorly understood. In this study, we report that HBXIP works in the event through up-regulating S100A4. We observed that HBXIP expression was positively correlated to that of S100A4 in 87 clinical breast cancer tissue samples. Then, we identified that HBXIP was able to up-regulate S100A4 expression in breast cancer cells. Notably, we observed the HBXIP nuclear localization, implying that HBXIP may be associated with the promoter of S100A4. Chromatin immunoprecipitation assay (ChIP) and electrophoretic mobility shift assay (EMSA) showed that HBXIP was able to bind to the nucleotides +200~+239 region of S100A4 promoter, containing two putative recognition motif of transcription factor STAT4 and GRβ. It suggests that HBXIP is able to activate S100A4 promoter via interacting with STAT4 in breast cancer cells, leading to the up-regulation of S100A4. In addition, we identified another pathway of S100A4 up-regulation mediated by HBXIP. We found that HBXIP activated the PTEN/PI3K/AKT signaling by inducing DNA methylation of PTEN, which subsequently boosted S100A4 expression. In function, we demonstrated that HBXIP enhanced the growth or migration of breast cancer cells through S100A4 in vivo and in vitro. Collectively, we conclude that HBXIP up-regulates S100A4 through activating S100A4 promoter involving STAT4 and inducing PTEN/PI3K/AKT signaling to promote growth and migration of breast cancer cells. Our finding provides new insight into the mechanism of HBXIP in promotion of the development of breast cancer.

Lupov IP, Voiles L, Han L, et al.
Acquired STAT4 deficiency as a consequence of cancer chemotherapy.
Blood. 2011; 118(23):6097-106 [PubMed] Free Access to Full Article Related Publications
Signal Transducer and Activator of Transcription 4 (STAT4) is a transcription factor that is activated by IL-12 signaling and promotes Th1-cell differentiation and IFN-γ production. Defective IFN-γ production because of STAT4 mRNA and protein deficiency occurs after autologous stem cell transplantation for lymphoma. In the present study, we investigated the mechanisms of STAT4 deficiency in lymphoma patients. The tumor-bearing state is not responsible, because STAT4 levels were not significantly different in PBMCs obtained from healthy control subjects compared with those from lymphoma patients before treatment. STAT4 protein levels were significantly decreased in PBMCs and T cells obtained from lymphoma patients after standard-dose chemotherapy. Furthermore, treatment of control PBMC cultures or a natural killer cell line with chemotherapy drugs in vitro also resulted in reduced STAT4 protein and diminished, IL-12-induced IFN-γ production. Translation of STAT4 protein was not impaired in chemotherapy-treated cells, whereas the STAT4 protein half-life was significantly reduced. Chemotherapy drugs promoted the ubiquitination and proteasomal degradation of STAT4. Treatment with the proteasome inhibitor bortezomib reversed chemotherapy-induced STAT4 deficiency and defective IFN-γ production. We conclude that acquired STAT4 deficiency in lymphoma patients is a consequence of treatment with chemotherapy, results that have important implications for the design of optimal immunotherapy for lymphoma.

Shu ST, Dirksen WP, Lanigan LG, et al.
Effects of parathyroid hormone-related protein and macrophage inflammatory protein-1α in Jurkat T-cells on tumor formation in vivo and expression of apoptosis regulatory genes in vitro.
Leuk Lymphoma. 2012; 53(4):688-98 [PubMed] Free Access to Full Article Related Publications
Parathyroid hormone-related protein (PTHrP) and macrophage inflammatory protein-1α (MIP-1α) have been implicated in the pathogenesis of adult T-cell leukemia/lymphoma, but their effects on T-cells have not been well studied. Here we analyzed the functions of PTHrP and MIP-1α on T-cell growth and death both in vitro and in vivo by overexpressing either factor in human Jurkat T-cells. PTHrP or MIP-1α did not affect Jurkat cell growth in vitro, but PTHrP increased their sensitivity to apoptosis. Importantly, PTHrP and MIP-1α decreased both tumor incidence and growth in vivo. To investigate possible mechanisms, polymerase chain reaction (PCR) arrays and real-time reverse transcription (RT)-PCR assays were performed. Both PTHrP and MIP-1α increased the expression of several factors including signal transducer and activator of transcription 4, tumor necrosis factor α, receptor activator of nuclear factor κB ligand and death-associated protein kinase 1, and decreased the expression of inhibitor of DNA binding 1, interferon γ and CD40 ligand in Jurkat cells. In addition, MIP-1α also increased the expression of transcription factor AP-2α and PTHrP increased expression of the vitamin D3 receptor. These data demonstrate that PTHrP and MIP-1α exert a profound antitumor effect presumably by increasing the sensitivity to apoptotic signals through modulation of transcription and apoptosis factors in T-cells.

Kristensen VN, Vaske CJ, Ursini-Siegel J, et al.
Integrated molecular profiles of invasive breast tumors and ductal carcinoma in situ (DCIS) reveal differential vascular and interleukin signaling.
Proc Natl Acad Sci U S A. 2012; 109(8):2802-7 [PubMed] Free Access to Full Article Related Publications
We use an integrated approach to understand breast cancer heterogeneity by modeling mRNA, copy number alterations, microRNAs, and methylation in a pathway context utilizing the pathway recognition algorithm using data integration on genomic models (PARADIGM). We demonstrate that combining mRNA expression and DNA copy number classified the patients in groups that provide the best predictive value with respect to prognosis and identified key molecular and stromal signatures. A chronic inflammatory signature, which promotes the development and/or progression of various epithelial tumors, is uniformly present in all breast cancers. We further demonstrate that within the adaptive immune lineage, the strongest predictor of good outcome is the acquisition of a gene signature that favors a high T-helper 1 (Th1)/cytotoxic T-lymphocyte response at the expense of Th2-driven humoral immunity. Patients who have breast cancer with a basal HER2-negative molecular profile (PDGM2) are characterized by high expression of protumorigenic Th2/humoral-related genes (24-38%) and a low Th1/Th2 ratio. The luminal molecular subtypes are again differentiated by low or high FOXM1 and ERBB4 signaling. We show that the interleukin signaling profiles observed in invasive cancers are absent or weakly expressed in healthy tissue but already prominent in ductal carcinoma in situ, together with ECM and cell-cell adhesion regulating pathways. The most prominent difference between low and high mammographic density in healthy breast tissue by PARADIGM was that of STAT4 signaling. In conclusion, by means of a pathway-based modeling methodology (PARADIGM) integrating different layers of molecular data from whole-tumor samples, we demonstrate that we can stratify immune signatures that predict patient survival.

Lin L, Benson DM, DeAngelis S, et al.
A small molecule, LLL12 inhibits constitutive STAT3 and IL-6-induced STAT3 signaling and exhibits potent growth suppressive activity in human multiple myeloma cells.
Int J Cancer. 2012; 130(6):1459-69 [PubMed] Free Access to Full Article Related Publications
We characterized the effects of a newly developed signal transducers and activators of transcription 3 (STAT3) inhibitor, LLL12 in multiple myeloma (MM) cells. LLL12 specifically inhibited STAT3 phosphorylation, nuclear localization, DNA binding activity, down-regulated STAT3 downstream genes, and induced apoptosis in MM cells. Importantly, LLL12 significantly inhibited STAT3 phosphorylation, induced apoptosis in primary MM cells which came from patients that were clinically resistant to lenalidomide and bortezomib. LLL12 is a potent inhibitor of cell proliferation with IC50 values ranging between 0.26 and 1.96 μM in MM and primary MM cells. LLL12 also inhibited STAT3 phosphorylation induced by interleukin-6 (IL-6) and interferon-α but not STAT1, STAT2, STAT4 and STAT6 phosphorylation induced by interferon-α, interferon-γ and IL-4 indicating the selectivity of LLL12 for STAT3. The selectively of LLL12 on STAT3 was further demonstrated on 21 protein kinases, which LLL12 had IC50 values ≥ 73.92 μM. In addition, the pretreatment of LLL12 blocked the promotion of the cell proliferation and resistance to lenalidomide by IL-6. Furthermore, LLL12 significantly blocked tumor growth of MM cells in mouse model. Our results indicate that LLL12 blocks constitutive STAT3 and IL-6 induced STAT3 signaling and may be a potential therapeutic agent for MM.

Tosolini M, Kirilovsky A, Mlecnik B, et al.
Clinical impact of different classes of infiltrating T cytotoxic and helper cells (Th1, th2, treg, th17) in patients with colorectal cancer.
Cancer Res. 2011; 71(4):1263-71 [PubMed] Related Publications
The tumor microenvironment includes a complex network of immune T-cell subpopulations. In this study, we systematically analyzed the balance between cytotoxic T cells and different subsets of helper T cells in human colorectal cancers and we correlated their impact on disease-free survival. A panel of immune related genes were analyzed in 125 frozen colorectal tumor specimens. Infiltrating cytotoxic T cells, Treg, Th1, and Th17 cells were also quantified in the center and the invasive margin of the tumors. By hierarchical clustering of a correlation matrix we identified functional clusters of genes associated with Th17 (RORC, IL17A), Th2 (IL4, IL5, IL13), Th1 (Tbet, IRF1, IL12Rb2, STAT4), and cytotoxicity (GNLY, GZMB, PRF1). Patients with high expression of the Th17 cluster had a poor prognosis, whereas patients with high expression of the Th1 cluster had prolonged disease-free survival. In contrast, none of the Th2 clusters were predictive of prognosis. Combined analysis of cytotoxic/Th1 and Th17 clusters improved the ability to discriminate relapse. In situ analysis of the density of IL17+ cells and CD8+ cells in tumor tissues confirmed the results. Our findings argue that functional Th1 and Th17 clusters yield opposite effects on patient survival in colorectal cancer, and they provide complementary information that may improve prognosis.

Chang JS, Wiemels JL, Chokkalingam AP, et al.
Genetic polymorphisms in adaptive immunity genes and childhood acute lymphoblastic leukemia.
Cancer Epidemiol Biomarkers Prev. 2010; 19(9):2152-63 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Childhood acute lymphoblastic leukemia (ALL) has been hypothesized to have an infection- and immune-related etiology. The lack of immune priming in early childhood may result in abnormal immune responses to infections later in life and increase ALL risk.
METHODS: The current analyses examined the association between childhood ALL and 208 single-nucleotide polymorphisms (SNP) of 29 adaptive immune function genes among 377 ALL cases and 448 healthy controls. Single SNPs were analyzed with a log-additive approach using logistic regression models adjusted for sex, age, Hispanic ethnicity, and race. Sliding window haplotype analyses were done with haplotypes consisting of 2 to 6 SNPs.
RESULTS: Of the 208 SNPs, only rs583911 of IL12A, which encodes a critical modulator of T-cell development, remained significant after accounting for multiple testing (odds ratio for each copy of the variant G allele, 1.52; 95% confidence interval, 1.25-1.85; P = 2.9 x 10(-5)). This increased risk was stronger among firstborn children of all ethnicities and among non-Hispanic children with less day care attendance, consistent with the hypothesis about the role of early immune modulation in the development of childhood ALL. Haplotype analyses identified additional regions of CD28, FCGR2, GATA3, IL2RA, STAT4, and STAT6 associated with childhood ALL.
CONCLUSION: Polymorphisms of genes on the adaptive immunity pathway are associated with childhood ALL risk.
IMPACT: Results of this study support an immune-related etiology of childhood ALL. Further confirmation is required to detect functional variants in the significant genomic regions identified in this study, in particular for IL12A.

Stanelle J, Döring C, Hansmann ML, Küppers R
Mechanisms of aberrant GATA3 expression in classical Hodgkin lymphoma and its consequences for the cytokine profile of Hodgkin and Reed/Sternberg cells.
Blood. 2010; 116(20):4202-11 [PubMed] Related Publications
The transcription factor network in Hodgkin lymphoma (HL) represents a unique composition of proteins found in no other hematopoietic cell. Among these factors, an aberrant expression of the T-cell transcription factor GATA3 is observed in B cell-derived Hodgkin and Reed/Sternberg (HRS) tumor cells. Herein, we elucidate the regulation and function of this factor in HL. We demonstrate binding of NFκB and Notch-1, 2 factors with deregulated activity in HL to GATA3 promoter elements. Interference with NFκB and Notch-1 activity led to decreased GATA3 expression, indicating a dependency of deregulated GATA3 expression on these transcription factors. Down-regulation of GATA3 in HL cell lines demonstrated its role in the regulation of IL-5, IL-13, STAT4, and other genes. A correlation between GATA3 and IL-13 expression was confirmed for HRS cells in HL tissues. Thus, GATA3 shapes the cytokine expression and signaling that is typical of HL. Conclusively, aberrant GATA3 expression in HRS cells is stimulated by the deregulated constitutive activity of NFκB and Notch-1, indicating a complex network of deregulated transcription factors in these cells. GATA3 activity significantly contributes to the typical cytokine secretion of and signaling in HRS cells, which presumably plays an essential role in HL pathogenesis.

Chang HC, Han L, Goswami R, et al.
Impaired development of human Th1 cells in patients with deficient expression of STAT4.
Blood. 2009; 113(23):5887-90 [PubMed] Free Access to Full Article Related Publications
IL-12 activates STAT4, which is a critical regulator of inflammation and T helper type I (Th1) lineage development in murine systems. The requirement for STAT4 in the generation of human Th1 cells has not been examined thoroughly. Compared with control Th1 cultures, expression of the Th1 genes IFNgamma, IL-12Rbeta2, and TNFalpha is greatly reduced in Th1 cultures of CD4 T cells isolated from lymphoma patients after autologous stem cell transplantation who have acquired STAT4 deficiency. Moreover, IL-4 and IL-5 production is increased in patient Th1 cultures though there are no defects in the development of Th2 cells. Reconstitution of STAT4 in patient T cells allowed recovery of IFNgamma and IL-12Rbeta2 expression, whereas ectopic expression of IL-12Rbeta2 did not rescue STAT4 expression, and increased IFNgamma production only to levels intermediate between control and patient samples. These results demonstrate that, as in murine systems, STAT4 is required for optimal human Th1 lineage development.

Nebozhyn M, Loboda A, Kari L, et al.
Quantitative PCR on 5 genes reliably identifies CTCL patients with 5% to 99% circulating tumor cells with 90% accuracy.
Blood. 2006; 107(8):3189-96 [PubMed] Free Access to Full Article Related Publications
We previously identified a small number of genes using cDNA arrays that accurately diagnosed patients with Sézary Syndrome (SS), the erythrodermic and leukemic form of cutaneous T-cell lymphoma (CTCL). We now report the development of a quantitative real-time polymerase chain reaction (qRT-PCR) assay that uses expression values for just 5 of those genes: STAT4, GATA-3, PLS3, CD1D, and TRAIL. qRT-PCR data from peripheral blood mononuclear cells (PBMCs) accurately classified 88% of 17 patients with high blood tumor burden and 100% of 12 healthy controls in the training set using Fisher linear discriminant analysis (FLDA). The same 5 genes were then assayed on 56 new samples from 49 SS patients with blood tumor burdens of 5% to 99% and 69 samples from 65 new healthy controls. The average accuracy over 1000 resamplings was 90% using FLDA and 88% using support vector machine (SVM). We also tested the classifier on 14 samples from patients with CTCL with no detectable peripheral involvement and 3 patients with atopic dermatitis with severe erythroderma. The accuracy was 100% in identifying these samples as non-SS patients. These results are the first to demonstrate that gene expression profiling by quantitative PCR on a selected number of critical genes can be employed to molecularly diagnosis SS.

Higashi T, Tsukada J, Yoshida Y, et al.
Constitutive tyrosine and serine phosphorylation of STAT4 in T-cells transformed with HTLV-I.
Genes Cells. 2005; 10(12):1153-62 [PubMed] Related Publications
STAT4 is a critical mediator of IL-12-stimulated gene regulation in T-helper type 1 (Th1) cell. IL-12 activates the Janus family tyrosine kinases JAK2 and Tyk2, which in turn phosphorylate STAT4 on tyrosine 693. The p38 mitogen-activated protein kinase (MAPK) signaling pathway is also activated in response to IL-12, followed by phosphorylation of STAT4 on serine 721, which is required for STAT4 full transcriptional activity. In the present study, we demonstrated constitutive activation of STAT4 in HTLV-I-transformed T-cell lines MT-2, MT-4 and HUT102 by immunoprecipitation, Western blotting and electrophoretic mobility shift assay (EMSA). In HTLV-I-transformed T-cell lines, STAT4 was constitutively phosphorylated not only on tyrosine 693 but also on serine 721, and formed a heterodimer with STAT3. Constitutive phosphorylation of its upstream activators, JAK2, Tyk2 and p38 MAPK was also observed in the cells. EMSA and transient transfection studies further showed that the high-affinity sis-inducible element (hSIE) preferentially binds the STAT3/STAT4 heterodimer and is constitutively transactivated in MT-2 cells in the absence of exogenous cytokine stimulation. When STAT4 expression vector was cotransfected along with STAT3 expression vector into MT-2 cells, STAT4 significantly synergized with STAT3 to transactivate hSIE, showing the functional importance of heterodimer formation between STAT4 and STAT3.

Turkson J
STAT proteins as novel targets for cancer drug discovery.
Expert Opin Ther Targets. 2004; 8(5):409-22 [PubMed] Related Publications
Signal transducer and activator of transcription (STAT) proteins are latent cytoplasmic transcription factors that were discovered in the context of cytokine and growth factor signalling. Normal STAT signalling is tightly controlled with finite kinetics, which is in keeping with standard cellular responses. However, persistent STAT activation has also been observed and is frequently associated with malignant transformation. Constitutive activation of STAT proteins, notably of Stat3 and Stat5, is detected in many human tumour cells and cells transformed by oncoproteins that activate tyrosine kinase signalling pathways. It is well-established that constitutively active Stat3 is one of the molecular abnormalities that has a causal role in oncogenesis. Aberrant Stat3 promotes uncontrolled growth and survival through dysregulation of gene expression, including cyclin D1, c-Myc, Bcl-xL, Mcl-1 and survivin genes, and thereby contributes to oncogenesis. Moreover, recent studies reveal that persistently active Stat3 induces tumour angiogenesis by upregulation of vascular endothelial growth factor induction, and modulates immune functions in favour of tumour immune evasion. Overall, studies have validated Stat3 as a novel target for cancer therapy, and hence provided the rationale for developing small-molecule Stat3 inhibitors. This review will discuss current evidence for the critical role of aberrant STAT signalling in malignant transformation, and examine the validity as well as the therapeutic potential of Stat3 as a cancer target. An update on the efforts to develop novel Stat3 inhibitors for therapeutic application will also be provided.

van Doorn R, Dijkman R, Vermeer MH, et al.
Aberrant expression of the tyrosine kinase receptor EphA4 and the transcription factor twist in Sézary syndrome identified by gene expression analysis.
Cancer Res. 2004; 64(16):5578-86 [PubMed] Related Publications
Sézary syndrome (Sz) is a malignancy of CD4+ memory skin-homing T cells and presents with erythroderma, lymphadenopathy, and peripheral blood involvement. To gain more insight into the molecular features of Sz, oligonucleotide array analysis was performed comparing gene expression patterns of CD4+ T cells from peripheral blood of patients with Sz with those of patients with erythroderma secondary to dermatitis and healthy controls. Using unsupervised hierarchical clustering gene, expression patterns of T cells from patients with Sz were classified separately from those of benign T cells. One hundred twenty-three genes were identified as significantly differentially expressed and had an average fold change exceeding 2. T cells from patients with Sz demonstrated decreased expression of the following hematopoietic malignancy-linked tumor suppressor genes: TGF-beta receptor II, Mxi1, Riz1, CREB-binding protein, BCL11a, STAT4, and Forkhead Box O1A. Moreover, the tyrosine kinase receptor EphA4 and the potentially oncogenic transcription factor Twist were highly and selectively expressed in T cells of patients with Sz. High expression of EphA4 and Twist was also observed in lesional skin biopsy specimens of a subset of patients with cutaneous T cell lymphomas related to Sz, whereas their expression was nearly undetectable in benign T cells or in skin lesions of patients with inflammatory dermatoses. Detection of EphA4 and Twist may be used in the molecular diagnosis of Sz and related cutaneous T-cell lymphomas. Furthermore, the membrane-bound EphA4 receptor may serve as a target for directed therapeutic intervention.

Tracey L, Villuendas R, Dotor AM, et al.
Mycosis fungoides shows concurrent deregulation of multiple genes involved in the TNF signaling pathway: an expression profile study.
Blood. 2003; 102(3):1042-50 [PubMed] Related Publications
Mycosis fungoides (MF) is the most frequent type of cutaneous T-cell lymphoma, whose diagnosis and study is hampered by its morphologic similarity to inflammatory dermatoses (ID) and the low proportion of tumoral cells, which often account for only 5% to 10% of the total tissue cells. cDNA microarray studies using the CNIO OncoChip of 29 MF and 11 ID cases revealed a signature of 27 genes implicated in the tumorigenesis of MF, including tumor necrosis factor receptor (TNFR)-dependent apoptosis regulators, STAT4, CD40L, and other oncogenes and apoptosis inhibitors. Subsequently a 6-gene prediction model was constructed that is capable of distinguishing MF and ID cases with unprecedented accuracy. This model correctly predicted the class of 97% of cases in a blind test validation using 24 MF patients with low clinical stages. Unsupervised hierarchic clustering has revealed 2 major subclasses of MF, one of which tends to include more aggressive-type MF cases including tumoral MF forms. Furthermore, signatures associated with abnormal immunophenotype (11 genes) and tumor stage disease (5 genes) were identified.

Watson CJ
Stat transcription factors in mammary gland development and tumorigenesis.
J Mammary Gland Biol Neoplasia. 2001; 6(1):115-27 [PubMed] Related Publications
Two members of the Stat family of transcription factors play a vital role in mouse mammary gland development. Stat5a was originally described as a regulator of milk protein gene expression and was subsequently shown to be essential for mammary development and lactogenesis. In contrast, Stat3 is an essential mediator of apoptosis and post-lactational regression. Other members of the Stat family may have specific, but as yet undemonstrated, functions in mammary development. However, since Stat1 activity is regulated during mammary development in a pattern different from Stats 3 and 5, this factor too may have a functional role. Although both Stat4 and Stat6 are expressed in mammary tissue, it seems unlikely that they will have a significant function as each of these Stats is activated in response to a limited number of cytokines. Given the essential regulatory roles of Stat signaling molecules in mammary development, it was not surprising to discover that constitutively activated Stat factors are a feature of human breast cancers. Sustained Stat activity has also been described in a variety of tumors including leukemias. The cause of this sustained activation is not clear but probably involves mutation of one of the many Stat regulatory proteins or dysregulation of other signaling pathways which modulate Stat activity. It is now important to understand the mechanism of constitutive Stat activity and to develop strategies which will abrogate aberrant Stat signaling in tumors in vivo.

Leonard WJ
Role of Jak kinases and STATs in cytokine signal transduction.
Int J Hematol. 2001; 73(3):271-7 [PubMed] Related Publications
The Janus family tyrosine kinase-signal transducer and activator of transcription (Jak-STAT) signaling pathway is broadly used by interferons and type I cytokines. These cytokines and interferons activate Janus family tyrosine kinases (Jak kinases), which in turn phosphorylate and thereby activate STAT proteins. Before activation, STAT proteins are cytosolic proteins; after activation, however, they are translocated to the nucleus where they function as transcription factors. This review summarizes salient features of the Jak-STAT pathway and focuses on the functional role of the different Jak kinases and STATs in vivo.

Imada K, Leonard WJ
The Jak-STAT pathway.
Mol Immunol. 2000 Jan-Feb; 37(1-2):1-11 [PubMed] Related Publications
A variety of important cellular functions are regulated by cytokines. The Jak-STAT pathway is one of the important signaling pathways downstream of cytokine receptors. Following binding of a ligand to its cognate receptor, receptor-associated Jaks are activated. STAT proteins are then in turn activated by tyrosine phosphorylation by Jak kinases, allowing their dimerization and subsequent translocation into the nucleus, where they modulate expression of target genes. Indispensable functions of Jaks and STATs in cytokine signaling in vivo have been revealed through knockout mouse studies. Moreover, the recent discovery of the CIS/SOCS/JAB/SSI family of inhibitors has contributed to understanding how this pathway is negatively regulated.

Showe LC, Fox FE, Williams D, et al.
Depressed IL-12-mediated signal transduction in T cells from patients with Sézary syndrome is associated with the absence of IL-12 receptor beta 2 mRNA and highly reduced levels of STAT4.
J Immunol. 1999; 163(7):4073-9 [PubMed] Related Publications
Sézary syndrome (SS) is the leukemic phase of cutaneous T cell lymphoma characterized by the proliferation of clonally derived CD4+ T cells that release cytokines of the Th2 T cell phenotype (IL-4, IL-5, IL-10), whereas Th1 T cell cytokines (IL-2, IFN-gamma) are markedly depressed as is expression of IL-12, a pivotal cytokine for Th1 cell differentiation. Normal Th1 cells express both the beta 1 and beta 2 chains of the IL-12 receptor (IL-12R) and tyrosine phosphorylate STAT4 in response to IL-12. Th2 T cells express only the IL-12R beta 1 and thus do not tyrosine phosphorylate STAT4 in response to IL-12. To determine whether SS cells are Th2-like at the level of IL-12 signal transduction, we analyzed RNA from seven patients for the presence of message for the IL-12R beta 1 and beta 2 genes using RNase protection assays and assessed whether IL-12 induced tyrosine-phosphorylation of STAT4 by immunoblotting. In PBL from six of seven SS patients tested, beta 2 message was expressed at low to undetectable levels and its expression could not be stimulated by either IFN-alpha or IFN- gamma, which stimulated beta 2 expression in control PBL. The absence of beta 2 expression is further supportive evidence for the Th2 lineage of SS cells. However, unlike normal Th2 cells, SS cells also showed severely reduced levels of STAT4, suggesting that they have a depressed response to any inducer of the STAT4 signal transduction pathway, including IFN-alpha. This is the first observation linking STAT4 gene expression with a human disease and suggests that dysregulation of STAT4 expression may be significant to the development and/or progression of SS.

Chen H, Lee JM, Wang Y, et al.
The Epstein-Barr virus latency BamHI-Q promoter is positively regulated by STATs and Zta interference with JAK/STAT activation leads to loss of BamHI-Q promoter activity.
Proc Natl Acad Sci U S A. 1999; 96(16):9339-44 [PubMed] Free Access to Full Article Related Publications
In Epstein-Barr virus (EBV)-associated tumors in nonimmunocompromised patients, EBV gene expression is highly restricted. EBV-encoded nuclear antigen (EBNA)-1 is expressed, whereas the immunogenic and proliferative EBNAs are not. This pattern of EBNA expression is generated by usage of the BamHI-Q promoter (Qp). We have determined that the JAK/STAT pathway positively regulates Qp activity. In transient-transfection assays, a Qp-CAT reporter was activated by cotransfected JAK-1 and by treatment of cells with the cytokine IL-6. The ability of Qp to bind signal transducer and activator of transcription (STAT) proteins was directly demonstrated by electrophoretic mobility-shift assay, and mutation of potential STAT-binding sites reduced Qp responsiveness to Janus kinase (JAK)-1. Consistent with a role for STATs in Qp function, Qp using Burkitt's lymphoma Rael cells and cultured nasopharyngeal carcinoma (NPC) cells contained nuclear STAT protein. We investigated whether the inability to maintain EBV-positive NPC cell lines in culture was related to Qp activity. Passaging of the NPC cell line HK666 led to activation of expression of BZLF1, which encodes Zta and loss of Qp function. Transient expression assays linked Zta expression to the down-regulation of Qp. Cotransfection of Zta reduced Qp activity in reporter assays. This negative regulation required Zta DNA-binding activity. We provide evidence that Zta up-regulation of p53 leads to p53-mediated interference with JAK/STAT activation of Qp. The data imply that JAK/STAT signaling has a role in EBV-associated malignancies.

Anderson R, Macdonald I, Corbett T, et al.
Construction and biological characterization of an interleukin-12 fusion protein (Flexi-12): delivery to acute myeloid leukemic blasts using adeno-associated virus.
Hum Gene Ther. 1997; 8(9):1125-35 [PubMed] Related Publications
Interleukin-12 (IL-12) is a cytokine that exhibits pleiotropic effects on lymphocytes and natural killer cells and has been shown to have promise for the immunotherapy of cancer. The combination of the immune costimulatory molecule B7.1 and IL-12 has been shown to be synergistic for T cell activation. By transfecting tumor cells with both IL-12 and B7.1 cDNAs, it may be possible to use these modified targets as vaccines. A major obstacle in designing a vector to deliver these genes results from the structure of IL-12. Functional IL-12 is a heterodimer composed of two distinct subunits that are encoded by separate genes on different chromosomes. Production of functional IL-12 requires the coordinated expression of both genes. This presents several problems in vectors, particularly those in which additional genes, either a co-stimulatory gene or a selectable marker, are inserted. Therefore, we have constructed a single cDNA that encodes a single-chain protein, called Flexi-12, which retains all of the biological characteristics of recombinant IL-12 (rIL-12). The monomeric polypeptide Flexi-12 is able to induce the proliferation of phytohemagglutinin (PHA) blasts, induce PHA blasts to secrete interferon-gamma (IFN-gamma) and additionally, by preincubation, enhance the killing of K562 targets by PBLs. These phenomena are in a dose-dependent manner comparable to that seen with rIL-12. We have also shown that tyrosine phosphorylation of the STAT 4 transcription factor, which has been shown to be unique to the IL-12 signaling pathway, occurs with Flexi-12 at levels similar to those seen with rIL-12. We have packaged Flexi-12 into a recombinant adeno-associated virus (AAV) and used this vector to infect acute myeloid leukemic (AML) blasts. Infected AML blasts produced between 2 and 6 ng of IL-12/10(6) cells per ml per 48 hr. These studies also confirm that AAV is an efficient delivery vehicle for cytokines to leukemic cells. Direct analysis of these modified cells acting as tumor vaccines is underway.

Yamamoto K, Kobayashi H, Arai A, et al.
cDNA cloning, expression and chromosome mapping of the human STAT4 gene: both STAT4 and STAT1 genes are mapped to 2q32.2-->q32.3.
Cytogenet Cell Genet. 1997; 77(3-4):207-10 [PubMed] Related Publications
Studies of transcriptional activation by interferons and a variety of cytokines have led to the identification of a family of proteins that serve as signal transducers and activators of transcription (STAT). STAT4 is phosphorylated following interleukin (IL)-12 stimulation and is essential for IL-12 signal transduction. The human STAT4 cDNA was cloned, and both STAT4 and STAT1 genes were mapped to human chromosome bands 2q32.2-->q32.3 by fluorescence in situ hybridization. These results suggest that STAT4 and STAT1 may have arisen via a tandem gene duplication. However, human STAT1 is expressed ubiquitously, whereas human STAT4 is expressed in several tissues including spleen, heart, brain, peripheral blood cells, and testis.

Pallard C, Gouilleux F, Bénit L, et al.
Thrombopoietin activates a STAT5-like factor in hematopoietic cells.
EMBO J. 1995; 14(12):2847-56 [PubMed] Free Access to Full Article Related Publications
Thrombopoietin (TPO) is a newly cloned cytokine which is the major regulator of circulating platelet levels, acting on both proliferation and differentiation of megakaryocytes. We have investigated the ability of TPO to activate the JAK/STAT pathway in megakaryocytic cell lines. We used either the granulocyte-macrophage colony-stimulating factor (GM-CSF)- and/or erythropoietin (EPO)-dependent UT7 cell line in which the murine TPO receptor (mumpl) had been transfected (mumpl-UT7 transfectants) or the MO7E and DAMI cells which express endogenous human TPO receptors. We demonstrated that TPO activates the kinase JAK2 and a STAT5-like transcriptional factor but not STAT1, STAT2, STAT3 or STAT4, in a very rapid and transient manner. In order to better ascertain the specificity of the activation of STAT5-related factor by TPO, we investigated the effect of other cytokines/growth factors. Both GM-CSF and EPO activated the STAT5-like factor. In contrast, neither interferon (IFN)-gamma nor the mitogenic stem cell factor (SCF) activated STAT5, although IFN-gamma did activate STAT1 in those cells. The hematopoietic DNA binding activity related to STAT5 was identified as a p97 tyrosine-phosphorylated protein band which exhibited identical gel mobility to the mammary STAT5. Because v-mpl, a truncated form of the TPO receptor c-mpl, was shown to be oncogenic, we tested the activity of v-mpl on STAT5 and found STAT5 constitutively activated in two different v-mpl-expressing cells, the transiently transfected Cos7 cells and the stable v-mpl-UT7 transfectants. Overall, our data indicate that STAT5 is widely expressed in hematopoietic cells and activated by a number of cytokines, including TPO, GM-CSF and EPO, but not by IFN-gamma or SCF.

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