Project description:This randomized phase I/II clinical trial is studying the side effects and best dose of gamma-secretase/notch signalling pathway inhibitor RO4929097 when given together with vismodegib and to see how well they work in treating patients with advanced or metastatic sarcoma. Vismodegib may slow the growth of tumor cells. Gamma-secretase/notch signalling pathway inhibitor RO4929097 may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Giving vismodegib together with gamma-secretase/notch signalling pathway inhibitor RO4929097 may be an effective treatment for sarcoma.
Project description:Analysis of five Notch signaling-dependent human T-ALL cell lines (ALLSIL, DND41, HPBALL, KOPTK1, TALL-1) treated with gamma-secretase inhibitor (GSI) to block Notch signaling. Samples include parental cells, cells rescued by retroviral transduction with ICN (a GSI-independent form of activated Notch1), and cells retrovirally transduced with c-Myc (an important downstream target of Notch1). Results allow segregation of bona fide Notch targets from other genes affected by gamma-secretase inhibition as well as from targets downstream of c-Myc. Thirty samples were analyzed. Five human T-ALL cell lines (ALLSIL, DND41, HPBALL, KOPTK1, TALL-1) were treated with gamma-secretase inhibitor (1.0 micromolar compound E) vs. DMSO vehicle control for 12 hours. Each cell line was also retrovirally transduced with ICN or c-Myc, FACS sorted, and then treated with GSI vs. DMSO.
Project description:γ-Secretase is a transmembrane protease complex responsible for processing multiple type I transmembrane proteins, including the amyloid precursor protein (APP) and NOTCH. Using a proteomics-based screening approach, we found that dedicator of cytokinesis protein 2 (DOCK2) interacts with the γ-secretase complex component Nicastrin (NCSTN), regulating NCSTN N45-mannosylation and the effects of γ-secretase on NOTCH receptors. Both genetically depleting DOCK2 and pharmacologically targeting NCSTN mannosylation via Kifunensine ameliorate Notch-dependent leukemia progression in vivo. Together, these results reveal a mechanism by which γ-secretase specifically recognizes its substrate and provide a direction for treating Notch-related diseases.
Project description:Analysis of five Notch signaling-dependent human T-ALL cell lines (ALLSIL, DND41, HPBALL, KOPTK1, TALL-1) treated with gamma-secretase inhibitor (GSI) to block Notch signaling. Samples include parental cells, cells rescued by retroviral transduction with ICN (a GSI-independent form of activated Notch1), and cells retrovirally transduced with c-Myc (an important downstream target of Notch1). Results allow segregation of bona fide Notch targets from other genes affected by gamma-secretase inhibition as well as from targets downstream of c-Myc.
Project description:Glucocorticoids are an essential component of the treatment of lymphoid malignancies and resistance to glucocorticoid therapy constitutes a prominent clinical problem in relapsed and refractory lymphoblastic leukemias. Constitutively active NOTCH signaling is involved in the pathogenesis of over 50% of T-cell lymphoblastic leukemia (T-ALL) which harbor activating mutations in the NOTCH1 gene. Aberrant NOTCH1 signaling has been shown to protect normal thymocytes from glucocorticoid induced cell death. Here we analyzed the interaction of glucocorticoid therapy with inhibition of NOTCH signaling in the treatment of T-ALL. Gamma-secretase inhibitors (GSI), which block the activation of NOTCH receptors, amplified the transcriptional changes induced by glucocorticoid treatment, including glucocorticoid receptor autoinduction and restored sensitivity to dexamethasone in glucocorticoid-resistant T-ALL cells. Apoptosis induction upon inhibition of NOTCH signaling and activation of the glucocorticoid receptor was dependent on transcriptional upregulation of BIM and subsequent activation of the mitochondrial/intrinsic cell death pathway. Finally, we used a mouse xenograft model of T-ALL to demonstrate that combined treatment with dexamethasone and a GSI results in improved antileukemic effects in vivo. These studies provide insight in the mechanisms of glucocorticoid resistance and serve as rationale for the use of glucocorticoid and GSIs in combination in the treatment of T-ALL. Experiment Overall Design: Duplicate samples (biologic replicas) from CUTLL1 cells were treated for 24 hours with vehicle only (DMSO), dexamethasone (1microM), a gamma-secretase inhibitor (CompE 100nM) and a combination of dexamethasome plus gamma secretase inhibitor at the same concentrations indicated before. Gene expression profiling was analyzed to identify gene expression signatures assocuated with glucocorticoid treatment (dexamethasone), inhibition of NOTCH1 by gamma secretase inhibitor (CompE) or the combination of both treatments.
Project description:To determine genes in FL HSCs that are sensitive to Notch signagling, E14.5 FL cells were cultured on DL1( to stimulate Notch signaling). Cells were cultured in the presence of DMSO (vehicle control) or gamma secretase inhibitor (1uM) for 4 hrs or 10hrs. Gamma secretase inhibitor was used to inhibit Notch signaling. SLAM-LSKs were sorted and used for RNA preparation.
Project description:To determine genes in FL HSCs that are sensitive to Notch signagling, E14.5 FL cells were cultured on DL1( to stimulate Notch signaling). Cells were cultured in the presence of DMSO (vehicle control) or gamma secretase inhibitor (1uM) for 4 hrs or 10hrs. Gamma secretase inhibitor was used to inhibit Notch signaling. SLAM-LSKs were sorted and used for RNA preparation. 7 biological replicates (14 totalt samples) were collected for cells cultured for 4hrs. 4 biological replicates (8 total samples) were collected from cells cultured for 10hrs. Each replicate consisted of a DMSO and GSI treated sample
Project description:The intramembrane protease gamma-secretase has broad physiological functions, but also contributes to Notch-dependent tumors and Alzheimer’s disease. To identify naturally short substrates and non-substrates of gamma-secretase, we used four human cell lines of different tissue origins, breast cancer MCF7 cells, cervix carcinoma HeLa cells, T cell leukemia Jurkat cells and lymphoma U937 macrophage-like cells. The cell lines were treated overnight with the established gamma-secretase inhibitor DAPT or DMSO as a control. The proteomes of membrane fractions were determined by nano-liquid chromatography-tandem mass spectrometry and label-free quantitative proteomics. TNFRSF12A, PTPRCAP and C16orf54 were identified as potential naturally short gamma-secretase substrates, whereas other proteins with a short ectodomain including ‘pituitary tumor-transforming gene 1-interacting protein’ (PTTG1IP) did not show an increased abundance upon DAPT treatment.
Project description:Lipopolysaccharide (LPS)/immunue complex (IC) stimulated macrophages produce cytokine profiles that differe from LPS-stimulated inflammatory macropahges. Notch signaling is activated in LPS/IC-stimulated macrophages and inhibition of Notch signaling reduced IL-10 production. This study investigated the effect of gamma-secretase inhibitor (GSI) that suppresses Notch signaling pathway, on gene expression profiles in macrophages activated by LPS/IC.
Project description:Notch signaling relies on ligand-induced proteolysis to liberate a nuclear effector that drives cell fate decisions. The location and timing of individual steps required for proteolysis and movement of Notch from membrane to nucleus, however, remain unclear. Here, we use proximity labeling with quantitative multiplexed mass spectrometry to monitor the microenvironment of endogenous Notch2 after ligand stimulation in the presence of a gamma secretase inhibitor and then as a function of time after inhibitor removal. Our studies show that gamma secretase cleavage of Notch2 occurs in an intracellular compartment and that formation of nuclear complexes and recruitment of chromatin-modifying enzymes occurs within 45 minutes of inhibitor washout. This work provides a spatiotemporal map of unprecedented detail tracking the itinerary of Notch from membrane to nucleus after activation and identifies molecular events in signal transmission that are potential targets for modulating Notch signaling activity.