Project description:Analysis of Foxp3(+)epigenetics(-) T cells, Foxp3(-)epigenetics(+) T cells, and Foxp3(+)epigenetics(+) T cells. Results indicate regulatory T cell (Treg) ontogenesis requires two independent processes, expression of the transcription factor Foxp3 and establishment of Treg epigenetic programs induced by T cell receptor (TCR) stimulation.
Project description:Analysis of Foxp3(+)epigenetics(-) T cells, Foxp3(-)epigenetics(+) T cells, and Foxp3(+)epigenetics(+) T cells. Results indicate regulatory T cell (Treg) ontogenesis requires two independent processes, expression of the transcription factor Foxp3 and establishment of Treg epigenetic programs induced by T cell receptor (TCR) stimulation. GFP+CD4+ and GFP-CD4+ splenocytes were sorted from DEREG and DEREG/Scurfy mice. These cells were activated with anti-CD3/CD28 antibodies, and then transduced with Foxp3-expressing retrovirus (pGCSamIN, NGFR marker). NGFR+ T cells sorted were subjected to microarray analysis (Affymetrix, mouse genome 430 2.0 array). To normalize the experimental conditions, Tregs (GFP+ T cells from DEREG) and Tconv (GFP- T cells from DEREG) were also activated and transduced with empty vector. Two replicates each.
Project description:Despite the identification of MYCN amplification as an adverse prognostic marker in neuroblastoma, MYCN inhibitors have yet to be developed. Here, by integrating evidence from a whole genome shRNA library screen and the computational inference of master regulator proteins, we identify Transcription Factor Activating Protein 4 (TFAP4) as a critical effector of MYCN amplification in neuroblastoma, providing a novel synthetic lethal target. We demonstrate that TFAP4 is a direct target of MYCN in neuroblastoma cells, and that its expression and activity strongly negatively correlate with neuroblastoma patient survival. Silencing TFAP4 selectively inhibits MYCN-amplified neuroblastoma cell growth both in vitro and in vivo, in xenograft mouse models. Mechanistically, silencing TFAP4 induces neuroblastoma differentiation, as evidenced by increased neurite outgrowth and up-regulation of neuronal markers. Taken together, our results demonstrate that TFAP4 is a master regulator of MYCN-amplified neuroblastoma and may represent a valuable novel therapeutic target.