Project description:Multiple cancer-associated single nucleotide polymorphisms (SNPs) have been mapped to conserved sequences within a 500 kilobase region upstream of the MYC oncogene on human chromosome 8q24. These SNPs may affect cancer development through altered regulation of MYC expression, but this hypothesis has been difficult to confirm. We generated mice deficient in Myc-335, a putative MYC regulatory element that contains rs6983267, a SNP accounting for more human cancer- related morbidity than any other genetic variant or mutation. In Myc-335 null mice, Myc transcripts were expressed in the intestinal crypts in a pattern similar to that in wild-type mice but at modestly reduced levels. The mutant mice displayed no overt phenotype but were markedly resistant to intestinal tumorigenesis induced by the APCmin mutation. These results establish that a cancer-associated SNP identified in human genome-wide association studies has a functional effect in vivo. Exon-array analysis of mouse colon tissues from Myc-335 null and wild-type mouse (both mice are male and from the same litter). Related ChIP-seq data available in Short Read Archive, Accession ERP001919
Project description:Multiple cancer-associated single nucleotide polymorphisms (SNPs) have been mapped to conserved sequences within a 500 kilobase region upstream of the MYC oncogene on human chromosome 8q24. These SNPs may affect cancer development through altered regulation of MYC expression, but this hypothesis has been difficult to confirm. We generated mice deficient in Myc-335, a putative MYC regulatory element that contains rs6983267, a SNP accounting for more human cancer- related morbidity than any other genetic variant or mutation. In Myc-335 null mice, Myc transcripts were expressed in the intestinal crypts in a pattern similar to that in wild-type mice but at modestly reduced levels. The mutant mice displayed no overt phenotype but were markedly resistant to intestinal tumorigenesis induced by the APCmin mutation. These results establish that a cancer-associated SNP identified in human genome-wide association studies has a functional effect in vivo.
Project description:Analysis of Gene Expression in KO mice lacking the NOTCH1-bound MYC putative enhancer located at +1.43K downstream of the MYC gene. Enrichment of MYC signature genes were analyzed by GSEA. Results show that MYC expression signature is indeed significantly enriched. Conditional Knockout or WT mice were treated with Tamoxifen or Veicle
Project description:We identified an enhancer element near IGF2 locus that is possibly involved with dopamine function and schizophrenia. A knockout mouse was generated for the enhancer element in the IGF2 locus. We then characterized the striatal synaptosomes ( i.e. biological fraction representing pre- post synaptic nerve terminal)by mass spectometry from WT and Igf2 enhancer KO mice.
Project description:Analysis of Gene Expression in KO mice lacking the NOTCH1-bound MYC putative enhancer located at +1.43K downstream of the MYC gene. Enrichment of MYC signature genes were analyzed by GSEA. Results show that MYC expression signature is indeed significantly enriched.
Project description:Chromosomal rearrangements are a frequent cause of oncogene deregulation in human malignancies. Overexpression of EVI1 is found in a subgroup of acute myeloid leukemia (AML) with 3q26 chromosomal rearrangements which are often therapy resistant. In a cohort of primary t(3;8)(q26;q24) AML samples we observed the translocation of a MYC super-enhancer to EVI1. We generated a patient-based t(3;8)(q26;q24) model in vitro using CRISPR-Cas9 technology and demonstrated hyper-activation of EVI1 by the hijacked MYC super-enhancer. One MYC super-enhancer element in particular, which recruits early hematopoietic regulators, is critical for EVI1 expression and enhancer-promoter interaction. This interaction is facilitated by a CTCF-bound motif upstream of the EVI1 promoter that acts as an enhancer-docking site in t(3;8) AML. Genomic analyses of 3q26-rearranged AML samples point to a common mechanism by which EVI1 uses this CTCF-bound enhancer-docking site to hijack early hematopoietic enhancers.
Project description:The transition from castration resistant prostate adenocarcinoma (CRPC) to neuroendocrine prostate cancer (NEPC) is emerging as an important mechanism of treatment resistance. NEPC are associated with over-expression and gene amplification of MYCN (encoding N-Myc). N-Myc is a bona fide driver oncogene in several rare tumor types, but its role in prostate cancer progression is not well established. Integrating a novel genetically engineered mouse model and human prostate cancer transcriptome data, we show that N-Myc over-expression leads to the development of poorly differentiated, invasive prostate cancer that is molecularly similar to human NEPC tumors which includes an abrogation of AR signaling and induction of Polycomb Repressive Complex 2 signaling and that N-Myc interacts with AR and this interaction depends on Enhancer of Zeste Homolog 2. Altogether, our data shows that N-Myc drives the neuroendocrine phenotype in prostate cancer.
Project description:Mitochondrial stress triggers both metabolic and transcriptomic reprogramming but its effects on tumor development remains unclear. It is also unknown whether the genetic status has any influence on the capacity of mitochondrial stress to control tumor development. To explore these issues, we generated a mouse model lacking the lipid transfer protein Stard7 in intestinal epithelial cells (IECs) and assessed tumor development in both Wnt-dependent tumor initiation and in inflammation-driven tumor development. The loss of Stard7 in both models of intestinal tumors impaired mitochondrial Complex I activity, led to a severe metabolic and lipidomic reprogramming and potentiated mTORC1 activation. As a result, levels of enzymes involved in serine biosynthesis were enhanced in Stard7-deficient IECs showing or not constitutive Wnt signaling. Strikingly, despite similar molecular signatures upon Stard7 deficiency in intestinal crypts showing or not constitutive Wnt signaling, Stard7 contributed to tumor development in AOM/DSS-treated mice but inhibits Wnt-driven cancer initiation in the intestine. Apc+/min mice lacking Stard7 in IECs developed more tumors in the distal colon as well as a specific microbiota signature. Collectively, our results suggest that the Apc genetic status critically controls the effects of mitochondrial stress on intestinal tumor development.
Project description:Neuroendocrine prostate cancer is an aggressive disease characterized by early metastasis, drug resistance and poor prognosis. Genome-wide association studies (GWAS) previously identified numerous single nucleotide polymorphisms (SNPs) associated with prostate cancer. SNP rs11067228 as a significant variant associated with castration-resistant metastasis (CM) in prostate cancer (PCa). However, mechanisms underlying activity of the rs11067228 risk variant remain unclear. Here, we demonstrated that risk SNP rs11067228 is located in an H3K27ac-enriched active enhancer, and that activity of that region affects castration-resistance and neuroendocrine differentiation in PCa cells. We identified the RNA-splicing factor SRRM4 as a functional target gene as shown in both cell line and xenograft model. In addition, overexpression of SRRM4 is sufficient to induce PCa cell drug resistance and neuroendocrine differentiation. Moreover, site-directed mutation of the rs11067228 non-risk G to the risk A allele enabled binding of the transcription factor SOX4, activating candidate target gene expression. Taken together, our findings indicated that the rs11067228-associated enhancer modulates expression of SRRM4 via allele-specific long-range chromatin interactions, thereby governing PCa drug resistance and neuroendocrine differentiation.