Abstract 1807: Tolfenamic acid inhibits medulloblastoma cell proliferation and tumor growth in mice by targeting Sp1 and survivin.

Abstract

Abstract Medulloblastoma (MB) is the most common malignant tumor of the central nervous system in children. MB requires intensive multimodality treatment that often causes extensive long term side-effects. The morbidities associated with intensive therapy for treating this malignancy are a serious concern in children. Hence research focusing on identifying novel agents with less toxicity is very important. Specificity protein1 (Sp1) is a transcription factor which regulates several genes involved in cell proliferation and cell survival. Sp1 is also known to mediate the expression of survivin, a member of the inhibitor of apoptosis protein family that is associated with aggressive disease and poor prognosis in multiple human cancers. Recently we showed that Tolfenamic acid (TA), a non-steroidal anti-inflammatory drug (NSAID) inhibits neuroblastoma cell growth by targeting Sp1 and survivin. Strategies to target Sp1 and transcriptional regulation of survivin for treating MB have not yet been evaluated. The aim of the current investigation was to test the anti-cancer activity of TA using in vitro assays and a mouse model for MB. Human MB cells, DAOY and D283, were treated with vehicle (DMSO) or increasing concentrations (5-20 μg/ml) of TA and cell viability was measured at 24, 48 and 72 hours post-treatment. TA inhibited MB cell growth in a time and dose dependent manner. MB cells were treated with vehicle (DMSO) or TA (10 or 20 μg/ml) and the effect on cell apoptosis was measured. Apoptotic cells were measured by flow cytometry (Annexin-V staining) and caspase (3/7, 8, and 9) activity was determined using Caspase Glo kits. TA up-regulated caspase activity and augmented the apoptotic cell population. The expression of Sp1, c-PARP and survivin was determined by Western blot analysis. TA significantly inhibited the expression of Sp1, c-PARP, and survivin. Cell cycle phase distribution was measured using flow cytometry and results revealed that TA caused G0/G1 arrest in MB cells. For the in vivo assay, athymic nude mice were subcutaneously injected with D283 cells and treated with TA (50 mg/kg 3 times/wk) for 4 weeks. TA treatment caused 30-40% decrease in tumor weight and volume. Tumor tissue was subjected to immunohistochemical analysis to evaluate the expression of Sp1 and survivin. Consistent with in vitro results, TA-induced tumor growth inhibition in mice was accompanied with a decrease in Sp1 and survivin expression in mice tumor tissue. These pre-clinical data demonstrate that TA can act as an anti-cancer agent in medulloblastoma potentially targeting Sp1 and survivin. Citation Format: Don Eslin, Chris M. Lee, Umesh T. Sankpal, Robert M. Sutphin, Riyaz Basha. Tolfenamic acid inhibits medulloblastoma cell proliferation and tumor growth in mice by targeting Sp1 and survivin. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1807. doi:10.1158/1538-7445.AM2013-1807