Project description:Activation of Signal Transducer and Activator of Transcription 3 (STAT3) is common in prostate cancers. STAT3 may induce cell proliferation and resistance to apoptosis, as well as promote tumor angiogenesis, invasion, and migration by activating gene expression. Many STAT3-dependent transcriptional responses are mediated through protein-protein interactions that involve the amino-terminal domain (N-domain). In this study, we found that inhibition of the STAT3 N-domain using novel inhibitor ST3-Hel2A-2 induces apoptotic death in prostate cancer cells. The cell death was accomponied by robust activation of pro-apoptotic gene. Using chromatin immunoprecipitation and tiling human promoter arrays (ChIP-chip), we have defined genome-wide targets of STAT3 in DU145 prostate cancer cells. We found that upregulated pro-apoptotic genes were bound by STAT3 in prostate cancer cells, and that STAT3 binding was decreased following inhibition of the STAT3 N-domain. DU145 cells were treated with ST3-Hel2A-2 or DMSO as a control for 3 hr. Total RNA has been extracted and prepared for hybridization on Affymetrix HG-U133A 2.0 arrays.
Project description:Activation of Signal Transducer and Activator of Transcription 3 (STAT3) is common in prostate cancers. STAT3 may induce cell proliferation and resistance to apoptosis, as well as promote tumor angiogenesis, invasion, and migration by activating gene expression. Many STAT3-dependent transcriptional responses are mediated through protein-protein interactions that involve the amino-terminal domain (N-domain). In this study, we found that inhibition of the STAT3 N-domain using novel inhibitor ST3-Hel2A-2 induces apoptotic death in prostate cancer cells. The cell death was accomponied by robust activation of pro-apoptotic gene. Using chromatin immunoprecipitation and tiling human promoter arrays (ChIP-chip), we have defined genome-wide targets of STAT3 in DU145 prostate cancer cells. We found that upregulated pro-apoptotic genes were bound by STAT3 in prostate cancer cells, and that STAT3 binding was decreased following inhibition of the STAT3 N-domain. STAT3 siRNA knockdow confirmed specificity of STAT3 binding and changes in gene expression. DU145 cells were treated with STAT3 siRNA or scrambled siRNA for 48hr. Total RNA has been extracted and prepared for hybridization on Affymetrix HG-U133A 2.0 arrays.
Project description:Activation of Signal Transducer and Activator of Transcription 3 (STAT3) is common in prostate cancers. STAT3 may induce cell proliferation and resistance to apoptosis, as well as promote tumor angiogenesis, invasion, and migration by activating gene expression. Many STAT3-dependent transcriptional responses are mediated through protein-protein interactions that involve the amino-terminal domain (N-domain). In this study, we found that inhibition of the STAT3 N-domain using novel inhibitor ST3-Hel2A-2 induces apoptotic death in prostate cancer cells. The cell death was accomponied by robust activation of pro-apoptotic gene. Using chromatin immunoprecipitation and tiling human promoter arrays (ChIP-chip), we have defined genome-wide targets of STAT3 in DU145 prostate cancer cells. We found that upregulated pro-apoptotic genes were bound by STAT3 in prostate cancer cells, and that STAT3 binding was decreased following inhibition of the STAT3 N-domain. STAT3 siRNA knockdow confirmed specificity of STAT3 binding and changes in gene expression.
Project description:Activation of Signal Transducer and Activator of Transcription 3 (STAT3) is common in prostate cancers. STAT3 may induce cell proliferation and resistance to apoptosis, as well as promote tumor angiogenesis, invasion, and migration by activating gene expression. Many STAT3-dependent transcriptional responses are mediated through protein-protein interactions that involve the amino-terminal domain (N-domain). In this study, we found that inhibition of the STAT3 N-domain using novel inhibitor ST3-Hel2A-2 induces apoptotic death in prostate cancer cells. The cell death was accomponied by robust activation of pro-apoptotic gene. Using chromatin immunoprecipitation and tiling human promoter arrays (ChIP-chip), we have defined genome-wide targets of STAT3 in DU145 prostate cancer cells. We found that upregulated pro-apoptotic genes were bound by STAT3 in prostate cancer cells, and that STAT3 binding was decreased following inhibition of the STAT3 N-domain.
Project description:Activation of Signal Transducer and Activator of Transcription 3 (STAT3) is common in prostate cancers. STAT3 may induce cell proliferation and resistance to apoptosis, as well as promote tumor angiogenesis, invasion, and migration by activating gene expression. Many STAT3-dependent transcriptional responses are mediated through protein-protein interactions that involve the amino-terminal domain (N-domain). In this study, we found that inhibition of the STAT3 N-domain using novel inhibitor ST3-Hel2A-2 induces apoptotic death in prostate cancer cells. The cell death was accomponied by robust activation of pro-apoptotic gene. Using chromatin immunoprecipitation and tiling human promoter arrays (ChIP-chip), we have defined genome-wide targets of STAT3 in DU145 prostate cancer cells. We found that upregulated pro-apoptotic genes were bound by STAT3 in prostate cancer cells, and that STAT3 binding was decreased following inhibition of the STAT3 N-domain.
Project description:Dendritic cells (DC) play a vital role in the induction of activation or tolerance of immune response. STAT3 is a master transcriptional regulator of immune response in DCs by positively or negatively regulating DC function, but the mechanisms are unknown. STAT3 is post-translationally modified by acetylation or phosphorylation. While much is understood about transcriptional targets of phosphorylated STAT3, the gene targets and the functional impact of acetylated-STAT3 remain unclear. We aimed to answer the gene targets of acetylated-STAT3 and test the hypothesis that acetylation of STAT3 plays a key role in negative regulation of DCs. We performed genome-wide binding analysis of acetyl-STAT3 by ChIP-Seq coupled with gene expression microarrays. Acetylation of STAT3 induced by SAHA increased its capability to bind to target DNA sites in genome. Theses binding sites were mostly proximal but some were also distal up to over 100 kb from transcription start site. Gene expression array showed 1701 genes up-regulated and 1668 genes down-regulated. Proximal binding of acety-STAT3 showed more effective transcription function than distal binding. In top 500 binding peaks, the frequency of canonical motifs bound by acetyl-STAT3 were significantly higher than that for noncanonical motifs (p<0.00001). Functional analysis revealed that acetyl-STAT3 regulates target genes by upregulating genes that are primarily involved in negative regulation of cytokine production and IL-10 signaling, or downregulating genes that are primarily involved in immune effector process and antigen processing/presentation. Upregulation of IL-10Ra by acetyl-STAT3 contributes to the enhanced sensitivity of IL-10 signaling and negative regulation of DC function. Bone marrow derived dendritic cells were treated with SAHA (500 nm) or diluent for 12 hours. ChIP was performed using antibodies against STAT3, H3K4me3 and matched IgG control. DNA binding profiles were generated by deep sequencing using Illumina HiSeq 2000.
Project description:Interleukin-21 (IL-21) is a pleiotropic cytokine that induces expression of transcription factor BLIMP1 (encoded by Prdm1), which regulates plasma cell differentiation and T cell homeostasis. We identified an IL-21 response element downstream of Prdm1 that binds the transcription factors STAT3 and IRF4, which are required for optimal Prdm1 expression. Genome-wide ChIP-Seq mapping of STAT3- and IRF4-binding sites showed that most regions with IL-21-induced STAT3 binding also bound IRF4 in vivo, and furthermore, revealed that the noncanonical TTCnnnTAA GAS motif critical in Prdm1 was broadly used for STAT3 binding. Comparing genome-wide expression array data to binding sites revealed that most IL-21-regulated genes were associated with combined STAT3-IRF4 sites rather than pure STAT3 sites. Correspondingly, ChIP-Seq analysis of Irf4_/_ T cells showed greatly diminished STAT3 binding after IL-21 treatment, and Irf4_/_ mice showed impaired IL- 21-induced Tfh cell differentiation in vivo. These results reveal broad cooperative gene regulation by STAT3 and IRF4. Affymetrix expression data: Prepare CD4+ T cells from spleen. CD4+ T cells were preactivated, rested, and treated with IL-21 for 1, 6, and 24 hours. ChIP-seq data: Profiling of IRF4 and Stat3 binding with and without IL-21 stimulation in wild type and IRF4 KO mice.