Project description:Stat5 is a latent transcription factor that regulates essential growth and survival functions in normal cells. Constitutive activity of Stat5 and the involvement of its C-terminally truncated variant have been implicated in blood cell malignancies and mammary or breast cancer. To distinguish the individual contributions of the Stat5 variants to mammary tumorigenesis, global gene-expression profiling was performed on transgenic STAT5-induced tumors. Experiment Overall Design: Mammary tumors derived from transgenic mice carrying one of two Stat5 variants were collected for RNA extraction and hybridization on Affymetrix GeneChip® Mouse Genome 430A 2.0 array.
Project description:Stat5 is a latent transcription factor that regulates essential growth and survival functions in normal cells. Constitutive activity of Stat5 and the involvement of its C-terminally truncated variant have been implicated in blood cell malignancies and mammary or breast cancer. To distinguish the individual contributions of the Stat5 variants to mammary tumorigenesis, global gene-expression profiling was performed on transgenic STAT5-induced tumors.
Project description:Constitutively active AR variants are truncated proteins lacking the c-terminal region containing the ligand binding domain (LBD) and the activation function 2 (AF-2). The expression of these AR variants in CRPC was also associated with the resistance to novel therapies such as enzalutamide and abiraterone acetate. These variants are also involved in tumor progression.
Project description:Constitutively active AR variants are truncated proteins lacking the c-terminal region containing the ligand binding domain (LBD) and the activation function 2 (AF-2). The expression of these AR variants in CRPC was also associated with the resistance to novel therapies such as enzalutamide and abiraterone acetate. These variants are also involved in tumor progression.
Project description:The goal of this experiment was to compare the gene expression programs mediated by androgen/AR vs. constitutively active, truncated AR variants in castration-resistant CWR-R1 prostate cancer cells. Because constitutive activity of truncated AR variants can mask androgen/AR target genes, the androgen/AR transcriptional program was assessed by silencing the trucnated AR 1/2/3/CE3 variant with siRNA targeting AR exon CE3 and treating cells with vehicle (ethanol) or 1nM DHT. Similarly, because full-length AR activity can mask truncated AR variant target genes, the AR variant transcriptional program was assessed under castrate conditions by selectively silencing full-length AR with siRNA targeting AR exon 7, and comparing this profile with CWR-R1 cells transfected wtih siRNA targeting AR exon 1, which silences all AR expression (full-length and truncated AR variants).
Project description:Activation of canonical Wnt signaling is sufficient and necessary to inhibit the migration of the QR.pa neuroblast of C. elegans. To identify targets of canonical Wnt signaling involved in this process we isolated QR lineage descendants by FACS from control (mab-5(gk670) mutant) animals and animals expressing a constitutively active, N-terminally truncated form of BAR-1/β-catenin in the QR lineage using the egl-17 promoter (ΔN-BAR-1Q). FACS isolation was based on the expression of mCherry and GFP markers under the control of wrt-2 and egl-17 promoters, respectively. We performed differential gene expression analysis to identified genes that are differentially expressed between control and constitutive activation of canonical Wnt signaling.
Project description:While PAX5 is an important tumor suppressor in B-ALL, it is also involved in oncogenic translocations coding for PAX5 fusion proteins. PAX5-JAK2 encodes a protein consisting of the PAX5 DNA-binding region fused to the constitutively active JAK2 kinase domain. Here, we studied the oncogenic function of PAX5-JAK2 in a mouse model expressing it from the endogenous Pax5 locus. The Pax5Jak2/+ mice rapidly developed an aggressive B-ALL in the absence of another cooperating mutation. The DNA-binding function and kinase activity of Pax5-Jak2, as well as IL-7 signaling, all contributed to leukemia development. Interestingly, all Pax5Jak2/+ tumors lost the wild-type Pax5 allele, allowing efficient DNA binding of Pax5-Jak2. While we could not find evidence for a nuclear role of Pax5-Jak2 as an epigenetic regulator, active phosphorylated Stat5 was present at a high level in Pax5Jak2/+ B-ALL tumors, consistent with increased expression of Stat5 target genes. Together, these data identified Pax5-Jak2 as an important nuclear driver of leukemia formation by maintaining phosphorylated Stat5 levels in the nucleus.
Project description:Notch signaling is widely implicated in mouse mammary gland development and tumorigenesis. To investigate the effects of acute activation of Notch signaling in the mammary epithelial compartment, we generated bi-transgenic MMTV-rtTA; TetO-NICD1 (MTB/TICNX) mice that conditionally express a constitutively active NOTCH1 intracellular domain (NICD1) construct in the mammary epithelium upon doxycycline administration.
Project description:STAT5 is critical for differentiation, proliferation and survival of progenitor B cells suggesting a possible role in Acute Lymphoblastic Leukemia (ALL). Herein, we show increased expression of activated STAT5 in ALL patients, which correlates with treatment outcome. Mutations in Ebf1 and Pax5, genes critical for B cell development have also been identified in human ALL. To determine whether mutations in Ebf1 or Pax5 synergize with STAT5 activation to induce ALL we crossed mice expressing a constitutively active form of STAT5 (Stat5b-CA) with mice heterozygous for Ebf1 or Pax5. Haploinsufficiency of either Pax5 or Ebf1 synergized with Stat5b-CA to rapidly induce ALL in 100% of the mice. The leukemic cells displayed reduced expression of both Pax5 and Ebf1 but this had little affect on most EBF1 or PAX5 target genes. However, a subset of these genes was deregulated and included a large percentage of potential tumor suppressor genes and oncogenes. Further, most of these genes appear to be jointly regulated by both EBF1 and PAX5. Our findings suggest a model whereby small perturbations in a self-reinforcing network of transcription factors critical for B cell development, specifically PAX5 and EBF1, cooperate with STAT5 activation to initiate ALL. Gene expression profiling was performed on cells isolated from lymph nodes of Stat5b-CA x Ebf1+/- and Stat5b-CA x Rag2-/- leukemic mice and pre B cells sorted from bone marrow of C57BL/6 mice and Stat5b-CA transgenic mice. 17 Samples.
Project description:Basal-like breast cancer is a heterogeneous disease characterised by the expression of basal cell markers, no oestrogen or progesterone receptor expression and a lack of HER2 overexpression. Recent studies have linked activation of the Wnt/beta-catenin pathway to basal-like breast cancer. Transgenic mice expressing N-terminally truncated stabilised beta-catenin in the mammary basal/myoepithelial cell layer (K5deltaNbetacat strain) develop mammary hyperplasias that progress to invasive carcinomas. Histological and microarray analyses of these lesions have revealed their high similarity to a subset of basal-like human breast tumours with squamous differentiation. As in human basal-like carcinomas, the Myc pathway was found to be activated in the mammary lesions of K5deltaNbetacat mice. Mammosphere and transplantation assays showed that a basal cell population with stem/progenitor characteristics was amplified in K5deltaNbetacat mouse preneoplastic glands. Myc deletion from the mammary basal layer of K5deltaNbetacat mice abolished both basal cell regenerative capacity and tumorigenesis. These results show that Myc is essential for beta-catenin-induced stem cell amplification and tumorigenesis and that basal stem/progenitor cells may be at the origin of a subset of basal-like breast tumours. mammary tissue from K5M-NM-^TNM-NM-2cat mice were dissected at successive stages of development (small hyperplasia (n=5), large hyperplasia (n=5), tumor (n=11) and control (n=4)) for RNA extraction and hybridization on Affymetrix microarrays
