Project description:Volumetric detection and accurate quantification of fluorescent proteins in entire animals would greatly enhance our ability to monitor biological processes in vivo. Here we present a quantitative tomographic technique for visualization of superficial and deep-seated (>2-3 mm) fluorescent protein activity in vivo. We demonstrate noninvasive imaging of lung tumor progression in a murine model, as well as imaging of gene delivery using a herpes virus vector. This technology can significantly improve imaging capacity over the current state of the art and should find wide in vivo imaging applications in drug discovery, immunology, and cancer research.
Project description:A1874 is a novel BRD4-degrading proteolysis targeting chimera (PROTAC). In primary colon cancer cells and established HCT116 cells, A1874 potently inhibited cell viability, proliferation, cell cycle progression, as well as cell migration and invasion. The BRD4-degrading PROTAC was able to induce caspase and apoptosis activation in colon cancer cells. Furthermore, A1874-induced degradation of BRD4 protein and downregulated BRD-dependent genes (c-Myc, Bcl-2, and cyclin D1) in colon cancer cells. Significantly, A1874-induced anti-colon cancer cell activity was more potent than the known BRD4 inhibitors (JQ1, CPI203, and I-BET151). In BRD4-knockout colon cancer cells A1874 remained cytotoxic, indicating the existence of BRD4-independent mechanisms. In addition to BRD4 degradation, A1874 cytotoxicity in colon cancer cells was also associated with p53 protein stabilization and reactive oxygen species production. Importantly, the antioxidant N-acetyl-cysteine and the p53 inhibitor pifithrin-? attenuated A1874-induced cell death and apoptosis in colon cancer cells. In vivo, A1874 oral administration potently inhibited colon cancer xenograft growth in severe combined immuno-deficient mice. BRD4 degradation and p53 protein elevation, as well as apoptosis induction and oxidative stress were detected in A1874-treated colon cancer tissues. Together, A1874 inhibits colon cancer cell growth through both BRD4-dependent and -independent mechanisms.
Project description:WD repeat domain 5 (WDR5), a chromatin regulator associated with MLL complex and MYC oncoproteins, was shown to be critical for oncogenesis in human cancers and represents an attractive drug target. Inhibitors for targeting protein-protein interaction interfaces (PPIs) within WDR5 were developed; however, they inhibited only a part of WDR5-mediated functional interactions, exerting rather limited antitumor effects. We report a cereblon (CRBN)-based proteolysis targeting chimera (PROTAC) of WDR5, MS40, which is capable of selectively degrading cellular WDR5 and well-established imide:CRBN targets such as Ikaros (IKZF1). MS40-induced WDR5 degradation caused disassociation of MLL complex off chromatin, resulting in a decrease of global H3K4me2. Transcriptomic profiling also revealed targets of both WDR5 and imide:CRBN to be repressed by MS40. In MLL-rearranged acute leukemias, which exhibit high IKZF1 expression and IKZF1 dependency, co-suppression of WDR5 and IKZF1/3 by MS40 is superior at suppressing tumor growth not only to WDR5 PPI inhibitors but also to a VHL-based WDR5 PROTAC, MS169, which selectively targets WDR5 only. Furthermore, MS40 suppressed growth of primary leukemia patient cells in vitro and patient-derived xenografts (PDX) in vivo. Collectively, we report the discovery of a dual WDR5 and Ikaros degrader as anti-cancer therapeutic.
Project description:WD repeat domain 5 (WDR5), a chromatin regulator associated with MLL complex and MYC oncoproteins, was shown to be critical for oncogenesis in human cancers and represents an attractive drug target. Inhibitors for targeting protein-protein interaction interfaces (PPIs) within WDR5 were developed; however, they inhibited only a part of WDR5-mediated functional interactions, exerting rather limited antitumor effects. We report a cereblon (CRBN)-based proteolysis targeting chimera (PROTAC) of WDR5, MS40, which is capable of selectively degrading cellular WDR5 and well-established imide:CRBN targets such as Ikaros (IKZF1). MS40-induced WDR5 degradation caused disassociation of MLL complex off chromatin, resulting in a decrease of global H3K4me2. Transcriptomic profiling also revealed targets of both WDR5 and imide:CRBN to be repressed by MS40. In MLL-rearranged acute leukemias, which exhibit high IKZF1 expression and IKZF1 dependency, co-suppression of WDR5 and IKZF1/3 by MS40 is superior at suppressing tumor growth not only to WDR5 PPI inhibitors but also to a VHL-based WDR5 PROTAC, MS169, which selectively targets WDR5 only. Furthermore, MS40 suppressed growth of primary leukemia patient cells in vitro and patient-derived xenografts (PDX) in vivo. Collectively, we report the discovery of a dual WDR5 and Ikaros degrader as anti-cancer therapeutic.
Project description:WD repeat domain 5 (WDR5), a chromatin regulator associated with MLL complex and MYC oncoproteins, was shown to be critical for oncogenesis in human cancers and represents an attractive drug target. Inhibitors for targeting protein-protein interaction interfaces (PPIs) within WDR5 were developed; however, they inhibited only a part of WDR5-mediated functional interactions, exerting rather limited antitumor effects. We report a cereblon (CRBN)-based proteolysis targeting chimera (PROTAC) of WDR5, MS40, which is capable of selectively degrading cellular WDR5 and the well-established IMiDs:CRBN targets such as Ikaros (IKZF1). MS40-induced WDR5 degradation caused disassociation of MLL complex off chromatin, resulting in a decrease of global H3K4me2. Transcriptomic profiling revealed that gene targets of WDR5 and IMiDs:CRBN were both repressed by MS40. In MLL-rearranged acute leukemias, which exhibit high IKZF1 expression and IKZF1 dependency, co-suppression of WDR5 and IKZF1/3 by MS40 is superior at suppressing tumor growth not only to WDR5 PPI inhibitors but also to a matched VHL-based WDR5 PROTAC, MS169, which selectively targets WDR5 only. Furthermore, MS40 suppressed growth of primary leukemia patient cells in vitro and patient-derived xenografts (PDX) in vivo. Collectively, we report the discovery of a dual WDR5 and Ikaros degrader as anti-cancer therapeutic.
Project description:Bioluminescent sensor proteins have recently gained popularity in both basic research and point-of-care diagnostics. Sensor proteins based on intramolecular complementation of split NanoLuc are particularly attractive because their intrinsic modular design enables for systematic tuning of sensor properties. Here we show how the sensitivity of these sensors can be enhanced by the introduction of catalytically inactive variants of the small SmBiT subunit (DarkBiTs) as intramolecular inhibitors. Starting from previously developed bioluminescent antibody sensor proteins (LUMABS), we developed single component, biomolecular switches with a strongly reduced background signal for the detection of three clinically relevant antibodies, anti-HIV1-p17, cetuximab (CTX), and an RSV neutralizing antibody (101F). These new dark-LUMABS sensors showed 5-13-fold increases in sensitivity which translated into lower limits of detection. The use of DarkBiTs as competitive intramolecular inhibitor domains is not limited to the LUMABS sensor family and might be used to boost the performance of other bioluminescent sensor proteins based on split luciferase complementation.
Project description:Targeted protein degradation offers an alternative modality to classical inhibition and holds the promise of addressing previously undruggable targets to provide novel therapeutic options for patients. Heterobifunctional molecules co-recruit a target protein and an E3 ligase, resulting in ubiquitylation and proteosome-dependent degradation of the target. In the clinic, the oral route of administration is the option of choice but has only been achieved so far by CRBN- recruiting bifunctional degrader molecules. We aimed to achieve orally bioavailable molecules that selectively degrade the BAF Chromatin Remodelling complex ATPase SMARCA2 over its closely related paralogue SMARCA4, to allow in vivo evaluation of the synthetic lethality concept of SMARCA2 dependency in SMARCA4-deficient cancers. Here we outline structure- and property-guided approaches that led to orally bioavailable VHL-recruiting degraders. Our tool compound, ACBI2, shows selective degradation of SMARCA2 over SMARCA4 in ex vivo human whole blood assays and in vivo efficacy in SMARCA4-deficient cancer models. This study demonstrates the feasibility for broadening the E3 ligase and physicochemical space that can be utilised for achieving oral efficacy with bifunctional molecules.
Project description:Certain RNA and DNA viruses that infect plants, insects, fish or poikilothermic animals encode Class 1 RNaseIII endoribonuclease-like proteins. dsRNA-specific endoribonuclease activity of the RNaseIII of rock bream iridovirus infecting fish and Sweet potato chlorotic stunt crinivirus (SPCSV) infecting plants has been shown. Suppression of the host antiviral RNA interference (RNAi) pathway has been documented with the RNaseIII of SPCSV and Heliothis virescens ascovirus infecting insects. Suppression of RNAi by the viral RNaseIIIs in non-host organisms of different kingdoms is not known. Here we expressed PPR3, the RNaseIII of Pike-perch iridovirus, in the non-hosts Nicotiana benthamiana (plant) and Caenorhabditis elegans (nematode) and found that it cleaves double-stranded small interfering RNA (ds-siRNA) molecules that are pivotal in the host RNA interference (RNAi) pathway and thereby suppresses RNAi in non-host tissues. In N. benthamiana, PPR3 enhanced accumulation of Tobacco rattle tobravirus RNA1 replicon lacking the 16K RNAi suppressor. Furthermore, PPR3 suppressed single-stranded RNA (ssRNA)--mediated RNAi and rescued replication of Flock House virus RNA1 replicon lacking the B2 RNAi suppressor in C. elegans. Suppression of RNAi was debilitated with the catalytically compromised mutant PPR3-Ala. However, the RNaseIII (CSR3) produced by SPCSV, which cleaves ds-siRNA and counteracts antiviral RNAi in plants, failed to suppress ssRNA-mediated RNAi in C. elegans. In leaves of N. benthamiana, PPR3 suppressed RNAi induced by ssRNA and dsRNA and reversed silencing; CSR3, however, suppressed only RNAi induced by ssRNA and was unable to reverse silencing. Neither PPR3 nor CSR3 suppressed antisense-mediated RNAi in Drosophila melanogaster. These results show that the RNaseIII enzymes of RNA and DNA viruses suppress RNAi, which requires catalytic activities of RNaseIII. In contrast to other viral silencing suppression proteins, the RNaseIII enzymes are homologous in unrelated RNA and DNA viruses and can be detected in viral genomes using gene modeling and protein structure prediction programs.