Project description:Bromodomain and extraterminal domain (BET) proteins have emerged as therapeutic targets in multiple cancers, including the most common primary adult brain tumor glioblastoma (GBM). Although several bet inhibitors have entered clinical trials, few are brain penetrant. We have generated UM-002, a novel brain penetrant BET inhibitor that reduces GBM cell proliferation in vitro and in a human cerebral brain organoid model. Since UM-002 is more potent than other BET inhibitors, it could potentially be developed for GBM treatment. Furthermore, UM-002 treatment reduces the expression of cell-cycle related genes in vivo, and reduces the expression of invasion related genes within the non-proliferative cells present in tumors as measured by single cell RNAsequencing. These studies suggest that BET inhibition alters the transcriptional landscape of GBM tumors, which has implications for designing combination therapies. Importantly, they also provide an integrated dataset that combines in vitro and ex vivo studies with in vivo single-cell RNA-sequencing to characterize a novel BET inhibitor in GBM.
Project description:Bromodomain and extraterminal domain (BET) proteins have emerged as therapeutic targets in multiple cancers, including the most common primary adult brain tumor glioblastoma (GBM). Although several BET inhibitors have entered clinical trials, few are brain penetrant. We have generated UM-002, a novel brain penetrant BET inhibitor that reduces GBM cell proliferation in vitro and in a human cerebral brain organoid model. Since UM-002 is more potent than other BET inhibitors, it could potentially be developed for GBM treatment. Furthermore, UM-002 treatment reduces the expression of cell-cycle related genes in vivo and reduces the expression of invasion related genes within the non-proliferative cells present in tumors as measured by single cell RNA-sequencing. These studies suggest that BET inhibition alters the transcriptional landscape of GBM tumors, which has implications for designing combination therapies. Importantly, they also provide an integrated dataset that combines in vitro and ex vivo studies with in vivo single-cell RNA-sequencing to characterize a novel BET inhibitor in GBM.
Project description:Bromodomain and extra-terminal domain (BET) proteins are therapeutic targets in several cancers including the most common malignant adult brain tumor glioblastoma (GBM). Multiple small molecule inhibitors of BET proteins have been utilized in preclinical and clinical studies. Unfortunately, BET inhibitors have not shown efficacy in clinical trials enrolling GBM patients. One possible reason for this may stem from resistance mechanisms that arise after prolonged treatment within a clinical setting. However, the mechanisms and timeframe of resistance to BET inhibitors in GBM is not known. To identify the temporal order of resistance mechanisms in GBM we performed quantitative proteomics using multiplex-inhibitor bead mass spectrometry and demonstrated that resistance to BET inhibitors in GBM treatment occurs rapidly within hours and involves the fibroblast growth factor receptor 1 (FGFR1) protein. Small molecule inhibition of BET proteins and FGFR1 simultaneously induces synergy in reducing GBM tumor growth in vitro and in vivo. Further, FGFR1 knockdown synergizes with BET inhibitor mediated reduction of GBM cell proliferation. Collectively, our studies suggest that co-targeting BET and FGFR1 may dampen resistance mechanisms to yield a clinical response in GBM.
Project description:Glioblastoma multiforme (GBM), the most advanced form of a large subset of brain tumors collectively known as glioma, is the most aggressive and invasive type of brain tumor. Patients usually experience a median survival range of 9 to 12 months. GBMs are extremely difficult to manage because of the tumor cellsâ tendency to migrate and pervade into adjacent tissues. Surgical resection of GBMs generally only slows disease progression because any remaining tumor cells proceed to migrate through brain tissues and reform a new tumor mass. It is hypothesized that the invasive phenotype of these tumor cells may be attributable to unique gene expression. Stationary core and invasive rim tumor cells were collected separately by laser capture microdissection (LCM) from 19 biopsy samples. Identification of differentially expressed genes in the tumor core and invasive rim can give valuable insight to the genes and pathways potentially involved with the invasive phenotype. This information can then be used to generate possible biomarkers, diagnostic markers, or drug targets. Human glioblastoma tumor samples were obtained from patients who underwent primary therapeutic brain tumor resection. All specimens were collected and submitted to the study under institutional review board approved protocols. None of the patients had been subjected to chemotherapy or radiotherapy prior to resection, in order to avoid genetic signatures that are due to exposure to alkylating agents and/or ionizing radiation. All specimens were verified as GBMs by a neuropathologist. Tumors are embedded in OCT, then sectioned in a cryostat at -20C, to a thickness of 8-10 um and placed onto HistoGene slides. Sections to be microdissected are removed from the -80C fixed and stained with an abbreviated Hematoxylin and Eosin protocol. Two thousand tumor core and invasive cells are dissected onto separate caps using the PixCell II instrument using CapSure⢠Macro LCM Caps. The CapSure⢠Macro LCM Caps LCM 0211 should be used with the AutoPix instrument. Cells in the tumor core are identified by nuclear atypia and size and captured using the larger spot sizes. Tumor cells immediately adjacent to necrotic areas, cortical areas, cells with small regular nuclei, endothelial and blood cells should be avoided. Individual white matter invading GBM cells can be identified by means of their nuclear atypia and heteropyknotic staining, which is consistent with that of the cells within the tumor core. They should be microdissected using the 7.5 um laser spot size and the initial power settings recommended by the PixCell II manual. After microdissection all harvested material should immediately be lysed on the cap by applying the lysis buffer (XB) from the PicoPure RNA Isolation Kit according to the PicoPure protocol and stored -80C. Cell populations harvested on different caps can be pooled at the time of RNA isolation. RNA integrity is varified by identification of distinct 28S and 18S ribosomal bands with an Agilent Bioanalyzer using the RNA 6000 Nano LabChip kit. Total RNA was isolated from 2000 LCM cells (to ensure at least 500 ng total RNA) using the PicoPure RNA solation Kit, following manufacturers protocol. mRNA is reverse transcribed with the RiboAmp RNA Amplification kit. 500 ng total RNA is amplified with the RiboAmp RNA Amplification kit, following manufacturerâs instructions. The total yield that can be expected falls between 30 and 60 µg copy RNA. The size of the copy RNA should be verified by gel electrophoresis. Approximately 500ng of copy RNA can be separated on a 1% agarose gel in TAE buffer. A smear of amplified material should be seen between 200 and 3000bp. Six µg amplified RNA are labeled in a RT with SuperScriptIII in the presence of dUTP Cy5 utilizing 6 µg random hexamers as primers. Universal reference RNA is amplified one round in the same manner and labeled with Cy3 dUTP. Labeled cDNA is hybridized overnight onto cDNA microarray. Following hybridization, arrays are washed, scanned and quantitated with the Axon GenePix 4000 microarray reader (Axon Instruments). Gene expression results are analyzed using GeneSpring (Silicon Genetics) software. Intensity dependent normalization is applied, where the ratio is reduced to the residual Lowess fit of the intensity versus ratio curve. The measured intensity of each gene is divided by its reference channel (signal from the universal reference RNA) in each sample. When the reference channel is below 10, the data point is considered uninformative. The ratios (sample over reference) for the tumor core experiments and invasive rim experiments are averaged and compared. Genes that are more than two-fold differentially regulated in the majority of the matched core/invasive rim sets are selected.
Project description:Bromodomain and extra-terminal domain (BET) proteins are therapeutic targets in several cancers including the most common malignant adult brain tumor glioblastoma (GBM). Multiple small molecule inhibitors of BET proteins have been utilized in preclinical and clinical studies. Unfortunately, BET inhibitors have not shown efficacy in clinical trials enrolling GBM patients. One possible reason for this may stem from resistance mechanisms that arise after prolonged treatment within a clinical setting. However, the mechanisms and timeframe of resistance to BET inhibitors in GBM is not known. To identify the temporal order of resistance mechanisms in GBM we performed quantitative proteomics using multiplex-inhibitor bead mass spectrometry and demonstrated that intrinsic resistance to BET inhibitors in GBM treatment occurs rapidly within hours and involves the fibroblast growth factor receptor 1 (FGFR1) protein. Additionally, small molecule inhibition of BET proteins and FGFR1 simultaneously induces synergy in reducing GBM tumor growth in vitro and in vivo. Further, FGFR1 knockdown synergizes with BET inhibitor mediated reduction of GBM cell proliferation. Collectively, our studies suggest that co-targeting BET and FGFR1 may dampen resistance mechanisms to yield a clinical response in GBM.
Project description:Glioblastoma multiforme (GBM) is the most prevalent and deadliest adult brain tumor. To systematically characterize the pathways governing brain invasion, we developed a three-dimensional (3D) ex vivo organotypic invasion model with clinical relevance to GBM. We used this model to enrich for highly invasive GBM cell population. Using next-generation sequencing to transcriptomically profile highly invasive and poorly invasive GBM cell populations, we have identified a network of extracellular matrix (ECM) components, including multiple collagens and collagen-interacting proteins, which are upregulated by invading GBM cells and strongly correlate in expression with clinical glioma progression outcomes. We identify the interferon regulatory factor 3 (IRF3) as a direct transcriptional repressor of ECM factors in GBM and show that IRF3 acts as an endogenous suppressor of GBM invasion. Therapeutic activation of IRF3 by inhibiting casein kinase 2 (CK2) -- a negative regulator of IRF3 phosphorylation -- downregulated the expression of ECM factors and suppressed GBM invasion in ex vivo and in vivo models across a panel of patient-derived GBM cell lines representative of the main molecular GBM subtypes in the clinic. Our findings illustrate an integrated and systematic approach for the discovery of novel pathways regulating brain tumor invasion and provide a strong mechanistic insight into the notorious, yet poorly understood, invasion capacity of GBM tumors.
Project description:Combination therapy with Smo and PI3K inhibitors results in a synergistic effect in reducing tumor growth in PTEN-deficient Glioblastoma. To identify consequences of combination therapy with an Smo inhibitor and a PI3K inhibitor on a genome-wide scale, we performed Affymetrix microarrays with two different PTEN-deficient GBMs treated with single drugs or combination therapy. A small set of genes was significantly affected by combination therapy in hBT70 and/or hBT112, including several genes implicated in GBM prognosis, or identified as targets of Shh, PI3K or S6 pathways 29-33 . There are two different human GBM tumors (BT70 and BT112). Both are PTEN deficient. Samples were treated with DMSO (Control), LDE225 at 1 uM for 5 days, BKM 120 100 nM for 5 days, or LDE225 1 uM and BKM 120 100 nM for 5 days (Combo). Two biological replicates of each condition were analyzed.
Project description:Glioblastoma multiforme (GBM), the most advanced form of a large subset of brain tumors collectively known as glioma, is the most aggressive and invasive type of brain tumor. Patients usually experience a median survival range of 9 to 12 months. GBMs are extremely difficult to manage because of the tumor cells’ tendency to migrate and pervade into adjacent tissues. Surgical resection of GBMs generally only slows disease progression because any remaining tumor cells proceed to migrate through brain tissues and reform a new tumor mass. It is hypothesized that the invasive phenotype of these tumor cells may be attributable to unique gene expression. Stationary core and invasive rim tumor cells were collected separately by laser capture microdissection (LCM) from 19 biopsy samples. Identification of differentially expressed genes in the tumor core and invasive rim can give valuable insight to the genes and pathways potentially involved with the invasive phenotype. This information can then be used to generate possible biomarkers, diagnostic markers, or drug targets.
Project description:Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults. Patients usually undergo surgery followed by aggressive radio- and chemotherapy with the alkylating agent temozolomide (TMZ). Still, median survival is only 12-15 months after diagnosis. Many human cancers including GBMs demonstrate addiction to MYC transcription factor signaling and can become susceptible to inhibition of MYC downstream genes. JQ1 is an effective inhibitor of BET Bromodomains, a class of epigenetic readers regulating expression of downstream MYC targets. Here, we show that BET inhibition decreases viability of patient-derived GBM cell lines. We propose a distinct expression signature of MYCN-elevated GBM cells that correlates with significant sensitivity to BET inhibition. In tumors showing JQ1 sensitivity, we found enrichment of pathways regulating cell cycle, DNA damage response and repair. As DNA repair leads to acquired chemoresistance to TMZ, JQ1 treatment in combination with TMZ synergistically inhibited proliferation of sensitive cells. Bioinformatic analyses showed that JQ1-sensitive cells could also respond to Aurora Kinase A inhibition which indeed showed synergistic efficacy in combination with BET inhibition. Collectively, our data suggest that BET inhibition could potentiate the efficacy of TMZ or could be combined with Aurora Kinase inhibitors in MYCN-elevated GBM.