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.
Project description:Neuroblastoma is an embryonal tumour of the peripheral sympathetic nervous system (SNS). One of the master regulator genes for peripheral SNS differentiation, the homeobox transcription factor PHOX2B, is mutated in familiar and sporadic neuroblastomas. Here we report that inducible expression of PHOX2B in the neuroblastoma cell line SJNB-8 down-regulates MSX1, a homeobox gene important for embryonic neural crest development. Inducible expression of MSX1 in SJNB-8 caused inhibition of both cell proliferation and colony formation in soft agar. Affymetrix micro- array and Northern blot analysis demonstrated that MSX1 strongly up-regulated the Delta-Notch pathway. These experiments describe for the first time regulation of the Delta-Notch pathway by MSX1, and connect these genes to the PHOX2B oncogene, indicative of a role in neuroblastoma biology. Experiment Overall Design: Time course experiments of two independent clones (K2 and K5), with 2 or 4 time points, respectively.
Project description:We investigated the effects of transfecting Malat1 antisense oligonucleotides on the whole Neuro2 neuroblastoma transcriptome. In this work, global transcription analyses were combined with detailed analyses of some synaptic genes. Our results provide insight on Malat1 effect on the regulation of gene expression in a mouse neuroblastoma cell line. Keywords: Comparative transcriptome analysis from Mus Musculus Neuro2 neuroblastoma cells transfected by Malat1 or Scamble oligodeoxynucleotides.
Project description:MYCN amplification in neuroblastoma leads to aberrant expression of MYCN oncoprotein, which binds active genes promoting transcriptional amplification. Yet how MYCN coordinates transcription elongation to meet productive transcriptional amplification and which elongation machinery represents MYCN-driven vulnerability remain to be identified. We conducted a targeted screen of transcription elongation factors and identified the super elongation complex (SEC) as a unique vulnerability in MYCN-amplified neuroblastomas. MYCN directly binds EAF1 and recruits SEC to enhance processive transcription elongation. Depletion of EAF1 or AFF1/AFF4, another core subunit of SEC, leads to a global reduction in transcription elongation and elicits selective apoptosis of MYCN-amplified neuroblastoma cells. A combination screen reveals SEC inhibition synergistically potentiates the therapeutic efficacies of FDA-approved BCL2 antagonist ABT-199, in part due to suppression of MCL1 expression, both in MYCN-amplified neuroblastoma cells and in patient-derived xenografts. These findings identify disruption of the MYCN-SEC regulatory axis as a promising therapeutic strategy in neuroblastoma.