Project description:We present a computational method for building a regulatory network from global phosphoproteomic and transcription profiling data. To recover the critical missing links between signaling events and transcriptional responses, we relate changes in chromatin accessibility to changes in expression and then uses these links to connect proteomic and transcriptome data. We applied our approach to integrate epigenomic, phosphoproteomic and transcriptome changes induced by the variant III mutation of the epidermal growth factor receptor (EGFRvIII) in a cell line model of glioblastoma multiforme (GBM).
Project description:We present a computational method for building a regulatory network from global phosphoproteomic and transcription profiling data. To recover the critical missing links between signaling events and transcriptional responses, we relate changes in chromatin accessibility to changes in expression and then uses these links to connect proteomic and transcriptome data. We applied our approach to integrate epigenomic, phosphoproteomic and transcriptome changes induced by the variant III mutation of the epidermal growth factor receptor (EGFRvIII) in a cell line model of glioblastoma multiforme (GBM). Genome-wide DNase I hypersensitivity followed by sequencing (DNase-Seq) to measure chromatin accessibility in a cell line derived from the U87MG glioblastoma cell line to express high level of EGFRvIII (U87H; 2 million copies of EGFRvIII per cell) and a control cell line expressing kinase dead EGFRvIII (U87DK; 2 million kinase dead EGFRvIII per cell). A prediction from the computational method, the transcriptional co-regulator p300, was experimentally validated by chromatin immunoprecipitation followed by sequencing (ChIP-Seq).
Project description:We found that the understudied Brain Specific Kinase 2 and 1 (BRSK2/1) proteins suppress NRF2-dependent transcription and NRF2 protein levels in a kinase-dependent fashion. Integrative phosphoproteomic screens, RNAseq profiling and follow-up validation studies revealed BRSK2/1-driven activation of AMPK and suppression of MTOR signaling. BRSK2 over-expression suppressed global protein synthesis and decreased ribosome-RNA associations, which results in decreased NRF2 protein levels. Overall, our data establish the BRSK1 and BRSK2 kinases as negative regulators of NRF2 via the AMPK/MTOR signaling axis.
Project description:Phosphotyrosine (pY) enrichment is critical for expanding fundamental and clinical understanding of cellular signaling by mass spectrometry-based proteomics. However, current pY enrichment methods exhibit a high cost per sample and limited reproducibility due to expensive affinity reagents and manual processing. We present rapid-robotic phosphotyrosine proteomics (R2-pY), which uses a magnetic particle processor and pY superbinders or antibodies. R2-pY can handle up to 96 samples in parallel, requires 2 days to go from cell lysate to mass spectrometry injections, and results in global proteomic, phosphoproteomic and tyrosine-specific phosphoproteomic samples. We benchmark the method on HeLa cells stimulated with pervanadate and serum and report over 4000 unique pY sites from 1 mg of peptide input, strong reproducibility between replicates, and phosphopeptide enrichment efficiencies above 99%. R2-pY extends our previously reported R2-P2 proteomic and global phosphoproteomic sample preparation framework, opening the door to large-scale studies of pY signaling in concert with global proteome and phosphoproteome profiling.
Project description:Activating Kras mutations are the hallmark genetic alterations in pancreatic ductal adenocarcinoma (PDAC) and key drivers of PDAC initiation and progression. Despite increased efforts to develop novel Kras inhibitors, the degree of Kras oncogene addiction in PDAC cells remains unclear. Here, we analyzed the requirement of endogenous Kras for the maintenance of murine PDAC cells using an inducible shRNA-based system that enables temporal control of endogenous Kras expression. Surprisingly, the majority of murine PDAC cells analyzed tolerated acute and sustained Kras knockdown by adapting to a reversible cell state, characterized by differences in cell morphology, proliferative kinetics, and tumor-initiating capacity. While significant mutational or transcriptional changes were not observed in the Kras-inhibited state, global phosphoproteomic profiling revealed alterations in cell signaling, including increased phosphorylation of focal adhesion pathway components. Accordingly, Kras-inhibited cells displayed prominent focal adhesion plaque structures, enhanced adherence properties, and increased dependency on adhesion for viability in vitro. Our analyses highlight the possibility of adaptive non-genetic and non-transcriptional mechanisms of resistance to Kras inhibition. Furthermore, we have identified candidate proteins whose signaling activities are altered in the Kras-inhibited state, providing a basis for the rational design of combination therapeutic strategies with novel Kras inhibitors.
Project description:We used microarrays to detail the global programme of gene expression in lung SCC cells treated with belinostat, a pan-HDAC inhibitor. The primary focus of this work is to investigate the efficacy of belinostat on lung SCC cells. Our phosphoproteomic profiling analyses revealed the downregulation of MAPK signaling pathway upon drug treatment, together with the induction of apoptosis. While HDAC inhibition generally affects transcription, the mechanism of SOS/MAPK downregulation was therefore proposed to be affected at the transcriptomic level. However, genes related to MAPK pathway were not significantly regulated upon belinostat treatment, whereas ubiquitin-proteasome gene signature was affected. This supports an indirect mechanism of epigenetic regulation on MAPK signaling that should be explored further.
Project description:Expression profiling of a total of 656 proteins in 3 high grade non-muslce invasive bladder cancer cases/normal urothelial mucosa pairs
Project description:ELABELA (ELA) is a peptide hormone required for heart development that signals via the Apelin Receptor (APLNR, APJ). ELA is also abundantly secreted by human embryonic stem cells (hESCs), which do not express APLNR. Here we show that ELA signals in a paracrine fashion in hESCs to maintain self-renewal. ELA inhibition by CRISPR/Cas9-mediated deletion, shRNA or neutralizing antibodies causes reduced hESC growth, cell death and loss of pluripotency. Global phosphoproteomic and transcriptomic analyses of ELA-pulsed hESCs show that it activates PI3K/AKT/mTORC1 signaling required for cell survival. ELA promotes hESC cell cycle progression and protein translation, and blocks stress-induced apoptosis. INSULIN and ELA have partially overlapping functions in hESC medium, but only ELA can potentiate the TGFβ pathway to prime hESCs towards the endoderm lineage. We propose that ELA, acting through an alternate cell-surface receptor, is an endogenous secreted growth factor in human embryos and hESCs that promotes growth and pluripotency. Global Transcriptomic Analysis of INSULIN versus ELA-pulsed human embryonic stem cells was performed to elucidate the functional overlap between these two ligands
Project description:Our results successfully showed through profiling of 8268 proteins that five autoantibodies in the metastatic group showed significantly higher intensities than non-metastatic and control groups Healthy or non-cancerous pediatric patients were pooled into a control group; Human ProtoArray that contains total 19200 protein spots of which 1326 are control spots and 8,268 are unique human proteins