Mojca Stampar

Vamorolone, a dissociative steroidal compound, reduces pro-inflammatory cytokine expression in glioma cells and increases activity and survival in a murine model of cortical tumor

Corticosteroids, such as dexamethasone, are routinely used as palliative care in neuro-oncology for their anti-inflammatory benefits, however many patients experience dose limiting side effects caused by glucocorticoid response element (GRE)-mediated transcription. The purpose of this study was to use a murine model to investigate a new steroid alternative, vamorolone, which promises to reduce side effects through dissociating GRE-mediated transcription and NF-κB -mediated anti-inflammatory actions. To compare vamorolone to dexamethasone in reducing pro-inflammatory signals in vitro, murine glioma cells were treated with dexamethasone, vamorolone or vehicle control. Changes in mRNA expression were assessed using the nanostring inflammatory platform. Furthermore, drug efficacy, post-treatment behavioral activity and side effects were assessed by treating two cohorts of brain tumor bearing mice with dexamethasone, vamorolone, or vehicle control. Our investigation showed that treatment with vamorolone resulted in a reduction of pro-inflammatory signals in tumor cells in vitro similar to treatment with dexamethasone. Treatment with vamorolone resulted in a better safety profile in comparison to dexamethasone treatment. Vamorolone- treated mice showed similar or better activity and survival when compared to dexamethasone-treated mice. Our data indicate vamorolone is a potential steroid-sparing alternative for treating patients with brain tumors.

Abstract 810: Establishing patient derived preclinical in vitro and in vivo models of pediatric brain cancers

The recent surge in understanding genomic aberrations of some of the deadliest childhood brain cancers has highlighted the need for robust preclinical models. Such models will allow for robust drug screening and preclinical evaluation of efficacy, toxicity, and tumor penetrance in vivo. Given the rarity and importance of patient derived specimens, handling and processing methods are perhaps the most critical steps for successful establishment of viable and reproducible in vitro and in vivo models. Since specimen source varies (biopsy, autopsy, or cryo-preserved), processing methods should be refined to allow for optimal extraction of maximum numbers of viable cells from each specimen type. We have developed standardized procedures for handling and processing of tissue samples obtained from biopsy, autopsy, or cryo-preserved specimens as well as necropsy tissue obtained from existing xenograft models. Two processing methods for generating viable cell suspensions are described. The first method, which uses collagenase-DNAse mediated digestion of the tissue is efficient with bulky samples and can be used with tissues obtained at autopsy. The second method uses a commercially available enzymatic dissociation kit optimal for small volume samples such as biopsy, cryo-preserved and mouse necropsy specimens. We show that obtaining viable cell suspension from precious tumor tissue by these methods results in successful generation of pre-clinical in vitro and in vivo models of DIPG, pilocytic astrocytoma and medulloblastoma that represent the exact genetic makeup of the original patient tumor. We further demonstrate intracranial injections of these cells into P2 mice for generating orthotopic xenograft models of brainstem or cortical tumors. Our methods and results allow for rapid establishment of preclinical models using rare and valuable childhood brain tumor specimens. These pre-clinical models serve as valuable tools for understanding the molecular mechanisms of the disease, identifying targetable molecules, and screening of novel therapeutics. Citation Format: Sridevi Yadavilli, Madhuri Kambhampati, Jamila Gittens, Eshini Panditharatna, Mojca Stampar, Lindsay B. Kilburn, Suresh Magge, Roger J. Packer, Javad Nazarian. Establishing patient derived preclinical in vitro and in vivo models of pediatric brain cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 810. doi:10.1158/1538-7445.AM2017-810