Project description:The emergence of drug-resistant viruses against nucleot(s)ide analogs (NAs), which are the main treatment for chronic hepatitis B virus (HBV) infection, has become a problem. To discover novel anti-HBV compounds with a low risk of emergence of drug-resistant viruses, we performed screening of a G protein-coupled receptor-associated compound library and identified Rimonabant as a candidate. Transcriptome analysis of Rimonabant-treated primary hepatocytes by RNA sequencing revealed that the transcriptional activity of HNF4α, which is known to stimulate viral RNA synthesis, was depressed.
Project description:There is a need to discover and develop non-toxic antibiotics that are effective against metabolically dormant bacteria, which underlie chronic infections and promote antibiotic resistance. Traditional antibiotic discovery has historically favored compounds effective against actively metabolizing cells, a property that is not predictive of efficacy in metabolically inactive contexts. Here, we combine a stationary-phase screening method with deep learning-powered virtual screens and toxicity filtering to discover compounds with lethality against metabolically dormant bacteria and favorable toxicity profiles. The most potent and structurally novel compound without any obvious mechanistic liability was semapimod, an anti-inflammatory drug effective against stationary-phase E. coli and A. baumannii. Integrating microbiological assays, biochemical measurements, and single-cell microscopy, we show that semapimod selectively disrupts and permeabilizes the bacterial outer membrane by binding lipopolysaccharide. This work illustrates the value of harnessing non-traditional screening methods and deep learning models to identify non-toxic antibacterial compounds that are effective in infection-relevant contexts.
Project description:We identified novel nicotinamide-based FLT3 inhibitors ( HSN748) that specifically target FLT3-ITD at sub-nanomolar concentrations and are effective against drug-resistant secondary mutations. In the current study, we evaluated these compounds’ antileukemic activity against FLT3-ITD and gatekeeper mutations in drug-resistant AML, relapsed/refractory AMLs with FLT3 mutations
Project description:Chemotherapy resistance is considered one of the main causes of tumor relapse, still challenging researchers for the identification of the molecular mechanisms sustaining its emergence. Here, we setup and characterized chemotherapy-resistant models of Medulloblastoma (MB), one of the most lethal pediatric brain tumors, to uncover targetable vulnerabilities associated to their resistant phenotype. Integration of proteomic, transcriptomic and kinomic data revealed a significant deregulation of several pathways in resistant MB cells, converging to cell metabolism, RNA/protein homeostasis, and immune response, eventually impacting on patient outcome. Moreover, resistant MB cell response to a large library of compounds through a high-throughput screening, highlighted nucleoside metabolism as a relevant vulnerability of chemotolerant cells, with peculiar antimetabolites demonstrating increased efficacy against them and even synergism with conventional chemotherapeutics. Our results suggest that drug-resistant cells significantly rewire multiple cellular processes, allowing their adaptation to a chemotoxic environment, nevertheless exposing alternative actionable susceptibilities for their specific targeting. In this study, we generated and characterized from a proteomic, transcriptional and kinomic point of view chemothrapy-resistant MB cells. Integrated data were then associated to the response of MB resistant cells to a large library of compounds through an high throughput screening approach identifying nucleoside metabolism as a peculiar targetable vulnerability emerged after chemotherapy adaptation.
Project description:Screening of various bisquaternary bisnaphthalimides against a variety of human pathogens revealed one compound, designated MT02, with strong inhibitory effects against gram-positive bacteria. The minimal inhibitory concentrations ranged from 0.31 µg/ml against community-acquired methicillin resistant Staphylococcus aureus (MRSA) strain USA300 to 20 µg/ml against Streptococcus pneumonia. DNA-microarray studies generated a transcriptional signature characterized by a strong increase of genes involved in DNA-metabolism, DNA-replication, SOS-response and transport of positively charged compounds. Radioactive whole cell labeling experiments indicated a strong impact of MT02 on bacterial DNA-replication. Furthermore, surface plasmon resonance and gel retardation experiments demonstrated direct binding of MT02 to DNA in a concentration dependent, reversible and sequence-unspecific manner. The data presented suggest that the bisquaternary bisnaphthalimide MT02 exerts anti-gram-positive activity by binding to DNA and thereby prohibiting appropriate DNA-replication. WT strain exposed to MT02 for 60 minutes in rich medium
Project description:Screening of various bisquaternary bisnaphthalimides against a variety of human pathogens revealed one compound, designated MT02, with strong inhibitory effects against gram-positive bacteria. The minimal inhibitory concentrations ranged from 0.31 µg/ml against community-acquired methicillin resistant Staphylococcus aureus (MRSA) strain USA300 to 20 µg/ml against Streptococcus pneumonia. DNA-microarray studies generated a transcriptional signature characterized by a strong increase of genes involved in DNA-metabolism, DNA-replication, SOS-response and transport of positively charged compounds. Radioactive whole cell labeling experiments indicated a strong impact of MT02 on bacterial DNA-replication. Furthermore, surface plasmon resonance and gel retardation experiments demonstrated direct binding of MT02 to DNA in a concentration dependent, reversible and sequence-unspecific manner. The data presented suggest that the bisquaternary bisnaphthalimide MT02 exerts anti-gram-positive activity by binding to DNA and thereby prohibiting appropriate DNA-replication.
Project description:T-box riboswitches belong to a specific class of RNA regulatory elements that control gene expression in Gram-positive bacteria, including prominent human pathogens. They sense the availability of amino acids by detecting the aminoacylation status of their cognate tRNAs and regulate the expression of genes involved in aminoacylation, amino acid transport, and metabolism. Recent advances on the structures and mechanisms of several regulatory non-coding RNAs among pathogenic bacteria have garnered attention for the development of a new generation of species-specific antibacterials. The frequently acquired resistance against current antibiotics has emerged as a significant challenge for healthcare systems and a serious threat to public health. Herein, we report the characterization of an effective T-box riboswitch inhibitor, termed T-box-i, which efficiently disrupts T-box riboswitch-mediated transcription in vivo. T-box-i was selected through a virtual screening campaign of commercially available small molecules against high-resolution crystallographic structures of T-box riboswitches. It exhibited no cytotoxicity in mammalian cells nor induced antibiotic resistance in S. aureus cultures. These findings provide valuable insights into exploiting T-box riboswitches as antibiotic targets and underscore the therapeutic potential of compounds that selectively target extensively structured regulatory RNA elements and interfaces to combat drug-resistant pathogens.