Crenolanib in Vitro Therapy in a RCAS/tv-a Murine Model of Di use Pontine Brainstem Glioma

Amitoz Manhas, MD1, Kelly Barton1, Gerald Grant, MD1, Oren Becher, MD1

1Durham, NC United States

Keywords: chemotherapy, glioma, brain stem, animal model, astrocytoma

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Abstract

     This recapitulates the genetic alteration of 30-40% of DIPGs, which harbor amplification of PDGFR-a. Despite clinical trials using chemotherapy, novel targeted agents, and radiation, the natural history of this disease has not been significantly affected and 90% of children with DIPGs die within 2 years of diagnosis.
     A first phase preclinical study was performed in a genetically engineered mouse model of Diffuse Intrinsic Pontine Glioma (DIPG). This model is driven by over-expression of PDGF-B ligand in nestin expressing cells in the brainstem of Ink4a-ARF deficient mice using the RCAS/tv-a gene transfer system.
     
     BSG cells were harvested from the BSG model and treated in vitro. BrdU and MTT assays were completed to evaluate the anti-tumor activity of a small molecule inhibitor of PDGFR-a (Crenolanib) alone and in combination with rapamycin relative to vehicle-treated cells.
     BrdU assays in vitro revealed the IC50 of Crenolanib to be 10nM in the PDGF-B-driven BSG tumor cells; the IC50 by MTT assays was 1.25µM. The IC50 of rapamycin by BrdU was 1 µM; when 10 nM Crenolanib and 1 µM rapamycin were combined and evaluated by BrdU assay, the inhibition of proliferation relative to vehicle-treated cells was greater than 90%.
     This study used a specific model that may not translate to humans.
     Crenolanib demonstrates significant anti-tumor activity in vitro in this genetically engineered mouse model of BSG.
     The in vivo evaluation of Crenolanib with systemic and convection-enhanced delivery (CED) therapy in this model is currently ongoing.


Acknowledgements

Project Roles:

A. Manhas (), K. Barton (), G. Grant (), O. Becher ()