Patient-based cancer models are essential tools for studying tumor biology and for the assessment of drug responses in a translational context. We report the establishment a large cohort of unique organoids and patient-derived orthotopic xenografts (PDOX) of various glioma subtypes, including gliomas with mutations in IDH1, and paired longitudinal PDOX from primary and recurrent tumors of the same patient. We show that glioma PDOXs enable long-term propagation of patient tumors and represent clinically relevant patient avatars that retain histopathological, genetic, epigenetic, and transcriptomic features of parental tumors. We find no evidence of mouse-specific clonal evolution in glioma PDOXs. Our cohort captures individual molecular genotypes for precision medicine including mutations in IDH1, ATRX, TP53, MDM2/4, amplification of EGFR, PDGFRA, MET, CDK4/6, MDM2/4, and deletion of CDKN2A/B, PTCH, and PTEN. Matched longitudinal PDOX recapitulate the limited genetic evolution of gliomas observed in patients following treatment. At the histological level, we observe increased vascularization in the rat host as compared to mice. PDOX-derived standardized glioma organoids are amenable to high-throughput drug screens that can be validated in mice. We show clinically relevant responses to temozolomide (TMZ) and to targeted treatments, such as EGFR and CDK4/6 inhibitors in (epi)genetically defined subgroups, according to MGMT promoter and EGFR/CDK status, respectively. Dianhydrogalactitol (VAL-083), a promising bifunctional alkylating agent in the current clinical trial, displayed high therapeutic efficacy, and was able to overcome TMZ resistance in glioblastoma. Our work underscores the clinical relevance of glioma organoids and PDOX models for translational research and personalized treatment studies and represents a unique publicly available resource for precision oncology.
Omacetaxine mepesuccinate (formerly homoharringtonine) is a molecule with a mechanism of action that is different from tyrosine kinase inhibitors and its activity in chronic myeloid leukemia (CML) seems to be independent of BCR-ABL mutation status. Using BCR-ABL-expressing myelogenous and lymphoid cell lines and mouse models of CML and B cell acute lymphoblastic leukemia (B-ALL) induced by wild type BCR-ABL or T315I mutant-BCR-ABL, we evaluated the inhibitory effects of omacetaxine on CML and B-ALL. We demonstrated that more than 90% of the leukemic stem cells were killed after treatment with omacetaxine in vitro. In contrast, less than 9% or 25% of the leukemic stem cells were killed after treating with imatinib or dasatinib, respectively. After 4 days of treatment of CML mice with omacetaxine, Gr-1+myeloid leukemia cells decreased in the peripheral blood of the treated CML mice. In the omacetaxine treated B-ALL mice, only 0.8% B220+leukemia cells were found in peripheral blood, compared with 34% B220+leukemia cells in the placebo group. Treatment with omacetaxine decreased the number of leukemia stem cells and prolonged survival of mice with BCR-ABL induced CML or B-ALL.
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