Therapy Resistance In Glioblastoma Research Articles

Abstract 2748: Aurora A kinase inhibitor MLN8237 suppresses neurosphere proliferation of pediatric glioblastoma and prolongs animal survival in patient tumor-derived orthotopic xenograft mouse model

Abstract Background: Pediatric glioblastoma (GBM) is highly aggressive and development of novel therapy is needed. Aurora A kinase is critical for mitosis and its overexpression results in malignant transformation of normal cells. MLN8237 (Alisertib) is the first orally available reversible selective inhibitor of the Aurora A serine/threonine kinase. We investigated the effects of MLN8237 on glioma stem cell proliferation and animal survival, as well as the effects on clinically-proven therapy resistant GBM cells. Methods: Levels of Aurora A kinase expression were screened in a panel of patient tumor-derived orthotopic xenograft mouse models. Anti-tumor effects was examined by Cell Counting Kit-8 assay in paired monolayer cell lines (in FBS-based media) and neurosphere cultures (in serum-free media containing EGF and bFGF) from two xenograft mouse models, IC-4687GBM (previously untreated) and IC-R0315GBM (established from a therapy-resistant autopsy sample). Therapeutic efficacy was examined in vivo by orally administered MLN8237 (30 mg/kg/day for 12 days) in NOD/SCID mice (n=10 per group) two weeks post intra-cerebral tumor cell implantation. Tumor growth was examined by MRI and histopathological analysis. Results: Overexpression of Aurora A kinase mRNA (4-10 fold over normal control) was observed in our pediatric GBM models. Tumor growth in FBS medium was suppressed in the previously untreated line (4687GBM) but not in the therapy-resistant line (R0315GBM). Cell growth of neurospheres, which are enriched with cancer stem cells, was suppressed in both GBM lines in a time- and dose-dependent manner. In IC-4687GBM, suppression of xenograft tumor growth was confirmed by MRI and histopathological analysis along with significant prolongation of animal survival in the treatment group. In the therapy-resistant model IC-R0315GBM, no significant suppression was observed, which correlates with the in vitro lack of effect on the monolayer cells. Conclusion: We detected high levels Aurora A kinase expression in pediatric GBM models and demonstrated the efficacy of MLN8237 in targeting GBM in vitro and in vivo. Our data in the therapy-resistant model IC-R0315GBM suggests the need for combination treatment in therapy-resistant GBMs. Our results support the evaluation of MLN8237 as a novel agent for pediatric GBMs. Citation Format: Mari Kogiso, Linna Zhang, Lin Qi, Holly B. Lindsay, Frank Y. Lin, Stacey Berg, Xiao-Nan Li, Jodi A. Muscal. Aurora A kinase inhibitor MLN8237 suppresses neurosphere proliferation of pediatric glioblastoma and prolongs animal survival in patient tumor-derived orthotopic xenograft mouse model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2748. doi:10.1158/1538-7445.AM2014-2748

Nanomolar concentrations of epothilone D inhibit the proliferation of glioma cells and severely affect their tubulin cytoskeleton.

The purpose of this study was to investigate the potential effects of epothilones (EPOs), a new class of microtubule stabilizing cytotoxic drugs, on glioma cells in vitro. The effects of 1, 10 and 100 nM concentrations of EPO D in four malignant human glioma cell lines were measured using a microtiter-tetrazolium assay. Besides the cell lines U87MG, U138MG and LN405, one cell line was used, which had been derived from a recurrent and therapy-resistant glioblastoma in our laboratory. In addition, changes of the cell morphology were followed by light microscopy and changes in the microtubule and actin cytoskeleton were visualized by a confocal laser microscope. In all four human glioma cell lines, 10 and 100 nM concentrations of the drug, applied for 96 h, lead to a highly significant decrease in the viable cell number (p < 0.001). A mean reduction of the viable cell number between 30% and 40% (60% and 90%) was observed for a drug concentration of 10 nM (100 nM). A round cell morphology occured in most EPO treated cells and the organized network of microtubules was shrunk in these round cells. The tubulin immunostaining now appeared amorphous and was restricted to small perinuclear regions. Large actin filaments also disappeared, but actin staining was present in the whole cytosplasm. These results prove that EPOs have antiproliferative effects in glioma cells and affect their tubulin cytoskeleton, as it was previously observed in several types of carcinoma cells.