PDTM-04. EARLY DETECTION BY MRI OF MOUSE MODELS WITH DIFFUSE INTRINSIC PONTINE GLIOMA

Abstract

Abstract Diffuse intrinsic pontine glioma (DIPG) is the most common brainstem tumor in childhood with a very devastating prognosis and no curative treatment options as of yet. Approximately 300 children in the U.S. are diagnosed with DIPG each year. Our project hopes to assess the effectiveness of OKlahoma Nitrone-007 (OKN-007) as a therapeutic agent for DIPG. This agent has shown promise in prior studies involving pediatric glioma mouse models by decreasing growth of blood vessels, which is essential for any tumor progression, and by decreasing temozolomide (TMZ) resistance when used as adjunct therapy in adult GBM. We have successfully created an in vivo DIPG model using post-mortem patient-derived neurospheres, harboring the H3 K27M mutation, injected into the pontine region of immunocompromised mouse (SCID) brainstems via a stereotaxic device. After surgical implantation, mice are imaged every week using a 7.0 Tesla 30-cm bore Bruker Biospec Magnetic Resonance Imaging (MRI) system to assess tumor growth and progression of disease. We describe to you the first pre-clinical DIPG mouse model that shows evidence of tumor growth as early as 42 days, as detected on T2-weighted MR images. Another characteristic feature is that the blood-brain barrier (BBB) is intact in this DIPG model, as assessed by contrast-enhanced MRI. Additional MRI methods, including diffusion-weighted imaging (DWI), and perfusion imaging (arterial spin labeling) are also evaluated. Prior pre-clinical DIPG mouse models only had tumor detection by MRI 78 days after implantation. Once the tumors are large enough for treatment (clinically relevant), we separate the mice into a control group (no treatment), OKN-007 treatment alone, as well as combination therapy with OKN-007 and TMZ. With the dismal prognosis and limited effective chemotherapy available for DIPG, there is significant room for continued research studies to help clinicians better understand and treat pediatric DIPG patients.