Project description:<p>The purpose of the original study was to search for somatic mutations in the tyrosine kinome of serous and clear cell endometrial carcinomas (human). The study was conducted in two phases.</p> <p>Phase 1: A mutation discovery screen, in which ~577 exons encoding the catalytic domains of 86 tyrosine kinases were PCR-amplified and bidirectionally Sanger sequenced from 24 serous, 11 clear cell, and 5 mixed histology endometrial tumors. This was followed by alignment of sequence reads to the human reference sequence and subsequent nucleotide variant calling to identify potential somatic (tumor-specific) mutations. Potential somatic mutations were confirmed by re-amplification and sequencing of the relevant tumor DNA as well as matched non-tumor ("normal") DNA from the same case.</p> <p>Phase 2: A mutation prevalence screen, in which the non-catalytic regions two tyrosine kinase genes, TNK2 and DDR1, were PCR-amplified and sequenced from the 40 discovery screen tumors, and all coding exons of TNK2 and DDR1 were PCR-amplified and sequenced from another 10 clear cell, 21 serous, and 41 endometrioid endometrial tumors, in an effort to identify additional somatic mutations in each gene. Exons encoding the exonuclease domain of POLE were also sequenced to document somatic mutations.</p>
Project description:Protein kinase inhibitors are effective cancer therapies, but acquired resistance often limits clinical efficacy. Despite the cataloguing of numerous resistance mutations with model studies and in the clinic, we still lack a comprehensive understanding of kinase inhibitor resistance. Here, we measured the resistance of thousands of Src tyrosine kinase mutants to a panel of ATP-competitive inhibitors. We found that ATP-competitive inhibitor resistance mutations are distributed throughout Src’s catalytic domain. In addition to inhibitor contact residues, residues that participate in regulating Src’s phosphotransferase activity were prone to the development of resistance. Unexpectedly, a resistance-prone cluster of residues that are on the top face of the N-terminal lobe of the catalytic domain contributes to Src autoinhibition by reducing the dynamics of the catalytic domain, and mutations in this cluster led to resistance by lowering inhibitor affinity and promoting kinase hyperactivation. Together, our studies demonstrate how comprehensive profiling of drug resistance can be used to understand potential resistance pathways and uncover new mechanisms of kinase regulation.
Project description:Extensive efforts are underway to identify anti-angiogenic therapies for the treatment of human cancers. Many proposed therapeutics target vascular endothelial cell growth factor (VEGF) or the kinase insert domain receptor (KDR/VEGFR-2/FLK-1), the mitogenic VEGF receptor tyrosine kinase expressed by endothelial cells. Inhibition of KDR catalytic activity blocks tumor neo-angiogenesis, reduces vascular permeability, and, in animal models, inhibits tumor growth and metastasis. Using a gene expression profiling strategy in rat tumor models, we identified a set of six genes that are selectively overexpressed in tumor endothelial cells relative to tumor cells, and whose pattern of expression correlates with the rate of tumor endothelial cell proliferation. In addition to being potential targets for anti-angiogenesis tumor therapy, the expression patterns of these genes or their protein products may aid the development of pharmacodynamic assays for small molecule inhibitors of the KDR kinase in human tumors. Keywords: Endothelial cell proliferation
Project description:Gastrointestinal stromal tumor (GIST) is a mesenchymal neoplasm characterized by activating mutations in the related receptor tyrosine kinases KIT or PDGFRA. GIST relies on expression of these unamplified receptor tyrosine kinase (RTK) genes through a large enhancer domain, producing high expression levels of the oncogene required for tumor growth. Though kinase inhibition is an effective therapy for many GIST patients, disease progression from kinase resistance mutations is common, and no other efficacious classes of systemic therapy exist. Given GIST’s reliance upon enhancer-driven expression of an RTK, we hypothesized that the enhancer domain could be therapeutically targeted by a BET bromodomain inhibitor (BBI). Treatment of GIST cells with BBIs led to cell cycle arrest, apoptosis and cell death, with unique sensitivity in GIST cells arising from attenuation of the KIT enhancer domain and reduced KIT gene expression. BBI treatment in KIT-dependent GIST cells produced genome-wide changes in the H3K27ac enhancer landscape and gene expression program, which was also seen with direct KIT inhibition using a tyrosine kinase inhibitor (TKI). Combination treatment with BBI and TKI led to synergistic cytotoxic effects in vitro and in vivo, with BBIs preventing tumor growth in TKI-resistant xenografts. A novel mechanism of resistance to select BBIs was found in GIST attributable to drug efflux pumps. These results define a therapeutic vulnerability and clinical strategy for targeting oncogenic kinase dependency in GIST.
Project description:Gastrointestinal stromal tumor (GIST) is a mesenchymal neoplasm characterized by activating mutations in the related receptor tyrosine kinases KIT or PDGFRA. GIST relies on expression of these unamplified receptor tyrosine kinase (RTK) genes through a large enhancer domain, producing high expression levels of the oncogene required for tumor growth. Though kinase inhibition is an effective therapy for many GIST patients, disease progression from kinase resistance mutations is common, and no other efficacious classes of systemic therapy exist. Given GIST’s reliance upon enhancer-driven expression of an RTK, we hypothesized that the enhancer domain could be therapeutically targeted by a BET bromodomain inhibitor (BBI). Treatment of GIST cells with BBIs led to cell cycle arrest, apoptosis and cell death, with unique sensitivity in GIST cells arising from attenuation of the KIT enhancer domain and reduced KIT gene expression. BBI treatment in KIT-dependent GIST cells produced genome-wide changes in the H3K27ac enhancer landscape and gene expression program, which was also seen with direct KIT inhibition using a tyrosine kinase inhibitor (TKI). Combination treatment with BBI and TKI led to synergistic cytotoxic effects in vitro and in vivo, with BBIs preventing tumor growth in TKI-resistant xenografts. A novel mechanism of resistance to select BBIs was found in GIST attributable to drug efflux pumps. These results define a therapeutic vulnerability and clinical strategy for targeting oncogenic kinase dependency in GIST.
Project description:Genome-wide DNA methylation profiling of 30 low-grade neuroepithelial tumors with FGFR1 alterations including rosette-forming glioneuronal tumor, pilocytic astrocytoma, dysembryoplastic neuroepithelial tumor, and extraventricular neurocytoma. The Illumina Infinium EPIC 850k Human DNA Methylation Beadchip was used to obtain DNA methylation profiles across approximately 850,000 CpG sites of genomic DNA extracted from formalin-fixed, paraffin-embedded tumor tissue of 30 low-grade neuroepithelial tumors with FGFR1 alterations including kinase domain tandem duplication, in-frame fusion with TACC1, and hotspot missense mutation within the intracellular tyrosine kinase domain.
Project description:Increased FTO expression has been connected to resistance to tyrosine kinase inhibitors in CML. To explore the therapeutic potential of targeting FTO in CML, we tested the FTO catalytic inhibitor in the K562 CML cell line. The RNA-seq was performed to identify relevant regulated genes.
Project description:Treatment induced-resistance of CRPC is an imminent undesirable outcome in patients. Tissue and lineage-specific super-enhancers (SEs) determine cell fate and plasticity during development and disease respectively. However, the identity and function of CRPC-specific SEs (CSEs) regulated genes is unknown. Herein we report the lysine 13 acetylation of the prostate-enriched transcription factor HOXB13 (acK13-HOXB13) mediated by the histone acetyl transferase (HAT) CBP/p300 as a critical mechanism of CSE establishment. Mechanistically, acK13-HOXB13 establishes the CRPC enhanceosome comprising chromatin remodeling bromo-domain proteins SMARCA2/BAZ2B and the HAT p300/CBP which enable histone and non-histone protein acetylation at CSEs. Such CSEs sprout at tyrosine kinase genes encoding ACK1/TNK2, VEGFA, and ANGPT2/ANGPTL3 to increase pathogenic output in primary human tumors. These tyrosine kinase mediated signaling cascades establish robust networks to conduce growth, survival and androgen-bypass. Consistently, the loss of function acK13-HOXB13 mutants show significant reduction of proliferation, spheroid formation, and xenograft tumor growth that correlates with the high sensitivity to the AR-antagonist Enzalutamide. Targeting HOXB13 acetylation mediated CRPC-SE establishment at critical tyrosine kinase genes could therefore have significant clinical implications in preventing PC recurrence.
Project description:Mammary specific deletion of Lfng induces basal-like and claudin-low tumors with accumulation of Notch intracellular domain fragments, increased expression of proliferation-associated Notch targets, amplification of the Met/Caveolin locus, and elevated Met and Igf-1R signaling. Tumor DNAs from Lfngflox/flox; MMTV-Cre conditional mutant mice are being compared to control DNAs from the same animals in order to identify common alterations associated with tumor progression