Project description:The expression of the extracellular sulfatase, SULF2, has been strongly associated with increased hepatocellular carcinoma (HCC) tumor growth and poorer patient survival. However, to date, the molecular mechanisms underlying this phenomenon remain in part unclear. To address this issue, we developed a transgenic mouse overexpressing Sulf2 in hepatocytes under the control of the transthyretin promoter. In this mouse model Sulf2 overexpression potentiated DEN-induced HCC. Further analysis demonstrated a central role for the zinc finger transcription factor Gli1 as a mediator of Sulf2 during HCC development. The cross of the Sulf2 transgenic with Gli1 knockout mice showed that the inactivation of this transcription factor impaired Sulf2-induced HCC. Transcriptomic analysis revealed a Stat3 gene signatures associated with Sulf2 overexpression. Interestingly, Gli1 knockout abrogates Sulf2-induction of several Stat3 target genes including Socs2/3, Pim1 and Flt4. Human orthologues were similarly regulated by SULF2 and dependent on intact GLI1 and STAT3 function in human HCC cells. SULF2 overexpression not only resulted in GLI1 and STAT3 interaction, but also promoted enrichment of GLI1 and STAT3 at consensus sites at the target gene promoters. Interestingly, GLI1 was found to be enriched at select STAT3 consensus sites with SULF2 overexpression and vice versa. siRNA-mediated knockdown of STAT3 or GLI1 reduced promoter binding of GLI1 and STAT3 respectively. Finally, chromatin capture PCR confirmed long-range co-regulation of SOCS2 and FLT3 through changes in promoter conformation. Thus, these findings define a novel mechanism by which SULF2 drives HCC and highlights the role of GLI1-STAT3 transcriptional complex as an effector of this sulfatase.
Project description:GLI1 is a transcription factor correlated to decreased survival in several cancers. We have identified SMARCA2 as a co-regulator that enhances GLI1-mediated transcriptional activity and functions through the C-terminal transcriptional activation domain of GLI1. Central domains including the ATPase motif of SMARCA2 physically interact with GLI1. Evaluation of DNA density indicates GLI1, like SMARCA2, can increase the DNA accessibility with a preference for sites distal to gene transcription start sites and outside the promoter regions (i.e. enhancers). The putative enhancers where accessibility is decreased by the knock down of GLI1 and SMARCA2 are located cis to genes, such as HHIP, that are regulated by GLI1 and implicated in cancer functions. At the putative enhancer for HHIP, the localization of SMARCA2 is at least partially dependent on GLI1’s presence. Understanding this transcriptional regulation by GLI1 and SMARCA2 through altering chromatin accessibility at enhances can provide additional therapeutic targets for cancers dependent on GLI1.
Project description:Increased expression of GLI1 is associated with poor prognosis for some breast cancer subtypes. A conditional transgenic GLI1 expressing mouse model, with or without heterozygous deletion of Trp53, was used to generate and study GLI1 induced mammary gland tumours. Tumour tissue was serially orthotopically transplanted for at least 10 generations in NSG mice.
Project description:GLI1 is a transcription factor correlated to decreased survival in several cancers. We have identified SMARCA2 as a co-regulator that enhances GLI1-mediated transcriptional activity and functions through the C-terminal transcriptional activation domain of GLI1. Central domains including the ATPase motif of SMARCA2 physically interact with GLI1. Evaluation of DNA density indicates GLI1, like SMARCA2, can increase the DNA accessibility with a preference for sites distal to gene transcription start sites and outside the promoter regions (i.e. enhancers). The putative enhancers where accessibility is decreased by the knock down of GLI1 and SMARCA2 are located cis to genes, such as HHIP, that are regulated by GLI1 and implicated in cancer functions. At the putative enhancer for HHIP, the localization of SMARCA2 is at least partially dependent on GLI1’s presence. Understanding this transcriptional regulation by GLI1 and SMARCA2 through altering chromatin accessibility at enhances can provide additional therapeutic targets for cancers dependent on GLI1.
Project description:Gli1 is necessary for the progression from chronic gastric inflammation to metaplasia in the stomach. We therefore compared the expression patterns between 6-month H. felis infected WT and Gli1-/- stomachs. Pooled tissue from the gastric fundi of 3 mice per group. Groups are WT, WT + H. felis (6 months), Gli1-/-, and Gli1-/- +H. felis (6 months). All the infected and control mice were obtained from the same experiment.
Project description:We sought to determine the effects of over-expression of Gli1 on gene expression in C2C12 myotube cultures. C2C12 myoblasts were induced to differentiate for 4 days. At that time, when >80% of nuclei were incorporated into multi-nucleated syncitial myotubes, we infected the cultures with recombinant adenovirus expressing GFP alone or GFP and a full length human Gli1. Media was changed 12 hours later. Cultures were lysed 60 hours after the initial infection. Gli1 over-expression induces de-differentiation of myotubes and proliferation of myoblasts. Results provide insight into the molecular basis of SHH signaling on skeletal muscle cells.
Project description:Skeletal growth promoted by endochondral ossification is tightly coordinated by self-renewal and differentiation of chondrogenic progenitors. Emerging evidence has shown that multiple skeletal stem cells (SSCs) participate in cartilage formation. However, as yet, no study has reported the existence of common long-lasting chondrogenic progenitors in various types of cartilage. Here, we identified Gli1+ chondrogenic progenitors (Gli1+ CPs), which were distinct from SSCs, were responsible for the lifelong generation of chondrocytes in the growth plate, vertebrae, ribs, and other cartilage. The absence of Gli1+ CPs led to cartilage defects and dwarfishness phenotype in mice. Furthermore, we found that the BMP signal played an important role in self-renewal and maintenance of Gli1+ CPs. The deletion of Bmpr1α caused the exhaustion of Gli1+ CPs, consequently disrupting columnar cartilage. Collectively, our data demonstrate that Gli1+ CPs are common long-term chondrogenic progenitors in multiple types of cartilage and are essential to maintain cartilage homeostasis.
Project description:hybridisation of mRNA from HaCaT keratinocytes expressing GLI1 or GLI2 in an tet-inducible manner for 24h or 72h on Incyte clone set Detailed information about the protocols we used for array production, hybridisation and analysation and the biological background of our experiments can be found in our publications: PMID: 15140221, 14691458, 12165851 Keywords = GLI1/2 target genes Keywords: time-course
Project description:This goal of this microarray analysis is to determine whether the mesonephros-derived theca cells exhibt a different gene expression profile from that of the whole theca cell population The mesonephros-derived (n=3, Tamoxifen at E12.5, E14.5 and E16.5) and the neonatal ovary-derived Gli1-positive cells (n=3 Tamoxifen at P1-3 via lactating dams), were isolated from the adult ovaries of Gli1-CreERT2; Rosa-LSL-tdTomato mice at 2 months of age and were sorted by FACS
Project description:SHH signaling pathway is activated in many type of cancers. However, the role of its activation in particular type of cancer was poorly understood. The GLI family transcription factor GLI1 is the effector of Shh pathway activation and functions as oncogene. Our goal of research is to identify the GLI1 targets in desmoplastic medulloblastomas. We used microarrays to obtain the global gene expression profiles in cells transformed by GLI1 and identified distinct classes of genes by comparing with those of desmoplastic medulloblastomas