A High-Throughput In Vitro Drug Screen in a Genetically Engineered Mouse Model of Diffuse Intrinsic Pontine Glioma Identifies BMS-754807 as a Promising Therapeutic Agent

Abstract

Diffuse intrinsic pontine gliomas (DIPGs) represent a particularly lethal type of pediatric brain cancer with no effective therapeutic options. Our laboratory has previously reported the development of genetically engineered DIPG mouse models using the RCAS/tv-a system, including a model driven by PDGF-B, H3.3K27M, and p53 loss. These models can serve as a platform in which to test novel therapeutics prior to the initiation of human clinical trials. In this study, an in vitro high-throughput drug screen as part of the DIPG preclinical consortium using cell-lines derived from our DIPG models identified BMS-754807 as a drug of interest in DIPG. BMS-754807 is a potent and reversible small molecule multi-kinase inhibitor with many targets including IGF-1R, IR, MET, TRKA, TRKB, AURKA, AURKB. In vitro evaluation showed significant cytotoxic effects with an IC50 of 0.13 μM, significant inhibition of proliferation at a concentration of 1.5 μM, as well as inhibition of AKT activation. Interestingly, IGF-1R signaling was absent in serum-free cultures from the PDGF-B; H3.3K27M; p53 deficient model suggesting that the antitumor activity of BMS-754807 in this model is independent of IGF-1R. In vivo, systemic administration of BMS-754807 to DIPG-bearing mice did not prolong survival. Pharmacokinetic analysis demonstrated that tumor tissue drug concentrations of BMS-754807 were well below the identified IC50, suggesting that inadequate drug delivery may limit in vivo efficacy. In summary, an unbiased in vitro drug screen identified BMS-754807 as a potential therapeutic agent in DIPG, but BMS-754807 treatment in vivo by systemic delivery did not significantly prolong survival of DIPG-bearing mice.

Pre-Clinical Study of Panobinostat in Xenograft and Genetically Engineered Murine Diffuse Intrinsic Pontine Glioma Models

“…To determine the effects of panobinostat on the growth, survival, and death of brainstem glioma (BSG) cells, we generated H3.3-K27M-expressing tumors by injecting neonatal Nestin-tv-a (Ntv-a);p53-fl/fl mice with RCAS-PDGF-B, RCAS-H3.3-K27M, and RCAS-Cre viruses as described in [22] and in Materials and Methods. In this autochthonous model, tumors are initiated via in vivo viral transduction of endogenous Nestin-expressing progenitors of the neonatal mouse brainstem, and tumor symptoms develop within 3–5 weeks of virus injection.…”

“…Nestin-Tv-a (Ntv-a); p53 fl/fl mice have been previously described [22] and were created by breeding Ntv-a mice with p53-floxed mice (C57BL/6J background) from Jackson Labs.…”

ABCG2 and ABCB1 Limit the Efficacy of Dasatinib in a PDGF-B–Driven Brainstem Glioma Model

“…Each cell-line was generated in the Becher lab in 2014 from one of our murine brainstem gliomas induced with PDGF-B and p53 loss in either ABC WT mouse background or ABK KO mouse background (ABC KO 1 = 14-801-1, ABC KO 2 = 12-801-2, ABC WT 1 = 14-410-1, ABC WT 2 = 14-506-2) as previously described (31). ABC transporter status of each cell-line was confirmed with genotyping in May 2015 and early passage cells were used for cell viability assays below (passage 3-5).…”

A Murine Model for Quantitative, Real-Time Evaluation of Convection-Enhanced Delivery (RT-CED) Using an 18[F]-Positron Emitting, Fluorescent Derivative of Dasatinib

“…Brain tissue was resected and flash frozen. The extracted glioma was excised, frozen, and submitted for immunohistochemical staining (supplementary figure 2, 3) (14). …”

“…However, Gd-based contrast agents are not effective therapeutics on their own, and require micromolar quantities to resolve (10–12). Gd-DTPA cannot serve as a universal indicator of drug distribution as the diffusive properties of a drug are related to molecular size, mass, hydrogen-bonding and partition coefficient, properties that widely vary between drugs and tracers (8,13,14). Positron emission tomography (PET) can be more sensitive than MR contrast (8,9,15), making PET uniquely useful for tracking chemotherapeutics at nanomolar concentration.…”