RESUMO
To study the behavior of MDM2-p53 inhibitors in a disease-relevant cellular model, we have developed and validated a set of bioorthogonal probes that can be fluorescently labeled in cells and used in high-content screening assays. By using automated image analysis with single-cell resolution, we could visualize the intracellular target binding of compounds by co-localization and quantify target upregulation upon MDM2-p53 inhibition in an osteosarcoma model. Additionally, we developed a high-throughput assay to quantify target occupancy of non-tagged MDM2-p53 inhibitors by competition and to identify novel chemical matter. This approach could be expanded to other targets for lead discovery applications.
Assuntos
Antineoplásicos/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Corantes Fluorescentes/análise , Indóis/farmacologia , Osteossarcoma/tratamento farmacológico , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Proteína Supressora de Tumor p53/antagonistas & inibidores , Antineoplásicos/química , Técnicas Biossensoriais , Linhagem Celular Tumoral , Corantes Fluorescentes/química , Humanos , Indóis/química , Modelos Moleculares , Estrutura Molecular , Osteossarcoma/patologia , Análise de Célula ÚnicaRESUMO
Fragile X syndrome (FXS) is the most common form of inherited mental retardation, and it is caused in most of cases by epigenetic silencing of the Fmr1 gene. Today, no specific therapy exists for FXS, and current treatments are only directed to improve behavioral symptoms. Neuronal progenitors derived from FXS patient induced pluripotent stem cells (iPSCs) represent a unique model to study the disease and develop assays for large-scale drug discovery screens since they conserve the Fmr1 gene silenced within the disease context. We have established a high-content imaging assay to run a large-scale phenotypic screen aimed to identify compounds that reactivate the silenced Fmr1 gene. A set of 50,000 compounds was tested, including modulators of several epigenetic targets. We describe an integrated drug discovery model comprising iPSC generation, culture scale-up, and quality control and screening with a very sensitive high-content imaging assay assisted by single-cell image analysis and multiparametric data analysis based on machine learning algorithms. The screening identified several compounds that induced a weak expression of fragile X mental retardation protein (FMRP) and thus sets the basis for further large-scale screens to find candidate drugs or targets tackling the underlying mechanism of FXS with potential for therapeutic intervention.