Exploring Predictors of Response to Dacomitinib in -Amplified Recurrent Glioblastoma.

Purpose: Despite the high frequency of genetic alterations in glioblastoma (GBM), EGFR-targeted therapies have not had success in this disease. To improve the likelihood of efficacy, we targeted adult patients with recurrent GBM enriched for gene amplification, which occurs in approximately half of GBM, with dacomitinib, a second-generation, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that penetrates the blood-brain barrier, in a multicenter phase II trial.

Patients And Methods: We retrospectively explored whether previously described extracellular domain (ECD)-sensitizing mutations in the context of gene amplification could predict response to dacomitinib, and in a predefined subset of patients, we measured post-treatment intratumoral dacomitinib levels to verify tumor penetration.

PI3K/AKT/mTOR Pathway Alterations Promote Malignant Progression and Xenograft Formation in Oligodendroglial Tumors.

Purpose: Oligodendroglioma has a relatively favorable prognosis, however, often undergoes malignant progression. We hypothesized that preclinical models of oligodendroglioma could facilitate identification of therapeutic targets in progressive oligodendroglioma. We established multiple oligodendroglioma xenografts to determine if the PI3K/AKT/mTOR signaling pathway drives tumor progression.

The Alkylating Chemotherapeutic Temozolomide Induces Metabolic Stress in -Mutant Cancers and Potentiates NAD Depletion-Mediated Cytotoxicity.

-mutant gliomas are dependent upon the canonical coenzyme NAD for survival. It is known that PARP activation consumes NAD during base excision repair (BER) of chemotherapy-induced DNA damage. We therefore hypothesized that a strategy combining NAD biosynthesis inhibitors with the alkylating chemotherapeutic agent temozolomide could potentiate NAD depletion-mediated cytotoxicity in mutant cancer cells.

Myc-Driven Glycolysis Is a Therapeutic Target in Glioblastoma.

Purpose: Deregulated Myc drives an oncogenic metabolic state, including pseudohypoxic glycolysis, adapted for the constitutive production of biomolecular precursors to feed rapid tumor cell growth. In glioblastoma, Myc facilitates renewal of the tumor-initiating cell reservoir contributing to tumor maintenance. We investigated whether targeting the Myc-driven metabolic state could be a selectively toxic therapeutic strategy for glioblastoma.

A new patient-derived orthotopic malignant meningioma model treated with oncolytic herpes simplex virus.

Background: Higher-grade meningiomas (HGMs; World Health Organization grades II and III) pose a clinical problem due to high recurrence rates and the absence of effective therapy. Preclinical development of novel therapeutics requires a disease model that recapitulates the genotype and phenotype of patient HGM. Oncolytic herpes simplex virus (oHSV) has shown efficacy and safety in cancers in preclinical and clinical studies, but its utility for HGM has not been well characterized.

Extreme Vulnerability of IDH1 Mutant Cancers to NAD+ Depletion.

Heterozygous mutation of IDH1 in cancers modifies IDH1 enzymatic activity, reprogramming metabolite flux and markedly elevating 2-hydroxyglutarate (2-HG). Here, we found that 2-HG depletion did not inhibit growth of several IDH1 mutant solid cancer types. To identify other metabolic therapeutic targets, we systematically profiled metabolites in endogenous IDH1 mutant cancer cells after mutant IDH1 inhibition and discovered a profound vulnerability to depletion of the coenzyme NAD+.

Rapid Intraoperative Molecular Characterization of Glioma.

Importance: Conclusive intraoperative pathologic confirmation of diffuse infiltrative glioma guides the decision to pursue definitive neurosurgical resection. Establishing the intraoperative diagnosis by histologic analysis can be difficult in low-cellularity infiltrative gliomas. Therefore, we developed a rapid and sensitive genotyping assay to detect somatic single-nucleotide variants in the telomerase reverse transcriptase (TERT) promoter and isocitrate dehydrogenase 1 (IDH1).

Sporadic hemangioblastomas are characterized by cryptic VHL inactivation.

Hemangioblastomas consist of 10-20% neoplastic "stromal" cells within a vascular tumor cell mass of reactive pericytes, endothelium and lymphocytes. Familial cases of central nervous system hemangioblastoma uniformly result from mutations in the Von Hippel-Lindau (VHL) gene. In contrast, inactivation of VHL has been previously observed in only a minority of sporadic hemangioblastomas, suggesting an alternative genetic etiology.

Targetable signaling pathway mutations are associated with malignant phenotype in IDH-mutant gliomas.

Purpose: Isocitrate dehydrogenase (IDH) gene mutations occur in low-grade and high-grade gliomas. We sought to identify the genetic basis of malignant phenotype heterogeneity in IDH-mutant gliomas.

Methods: We prospectively implanted tumor specimens from 20 consecutive IDH1-mutant glioma resections into mouse brains and genotyped all resection specimens using a CLIA-certified molecular panel.

Mesenchymal differentiation mediated by NF-κB promotes radiation resistance in glioblastoma.

Despite extensive study, few therapeutic targets have been identified for glioblastoma (GBM). Here we show that patient-derived glioma sphere cultures (GSCs) that resemble either the proneural (PN) or mesenchymal (MES) transcriptomal subtypes differ significantly in their biological characteristics. Moreover, we found that a subset of the PN GSCs undergoes differentiation to a MES state in a TNF-α/NF-κB-dependent manner with an associated enrichment of CD44 subpopulations and radioresistant phenotypes.