Abstract 2467: Association of specificity protein 1 and survivin expression in medulloblastoma: Identifying effective therapeutic targets

Medulloblastoma (MB) is an aggressive malignant brain tumor diagnosed mostly in children. MB is typically treated using a multimodal approach consisting of surgery, craniospinal irradiation, and chemotherapy. These treatments cause delayed consequences in pediatric patients. In order to treat this malignancy effectively, it is important to identify critical markers associated with the disease and finding specific agents to target such markers. The transcription factor, Specificity protein 1 (Sp1) and an inhibitor of apoptosis protein, survivin are over expressed in many cancers and associated with poor prognosis. Sp1 mediates the expression of several oncogenes including survivin. Even though some evidence exists for the expression of survivin, the information on Sp1 is still limited in MB. The primary objective of this study was to determine the association of Sp1 and survivin in MB and developing the strategies to target these candidates using less toxic compounds. A human MB tumor tissue array consisting of 20 tumor and 3 normal controls was stained for Sp1 and survivin using specific antibodies. Tumor specimens showed distinct expression for both Sp1 and survivin in majority of tumor tissues. Using small interference RNA (siRNA) technology, the expression of Sp1 and survivin was inhibited in MB cell line, DAOY, and the cell viability was determined at 24 and 48 h using CellTiter-Glo kit. We observed that the inhibition of Sp1 and survivin by siRNA correlated with a decrease in DAOY cell viability. Previously, our laboratory showed that a small molecule, Tolfenamic Acid (TA) inhibits cell proliferation and tumor growth in mice via targeting Sp1 and anti-apoptotic protein, survivin. Taken together these results highlight the significance of targeting Sp1 and survivin for inhibiting MB cell proliferation and tumor growth in mouse model. Survivin has also been demonstrated to play a role in chemoresistance. We therefore, tested the combination treatment(s) involving TA and standard chemotherapeutic agents, Vincristine (Vinc) and Cisplatin (Cis) using MB cell lines, DAOY and D283. Cells were treated with TA, Vinc, Cis and combination of TA+Vinc and TA+Cis and the effect on cell viability and apoptosis was determined. Each drug alone caused a time and dose dependent decrease in cell viability that was enhanced in the presence of TA. The combination treatment also resulted in a 2-3 fold increase in apoptosis as determined by annexin V and propidium iodide staining. It is plausible that targeting Sp1 and/or survivin induces the susceptibility of MB cells to chemotherapeutic drugs. These preliminary results demonstrate the efficacy of combining inhibitors of Sp1 and survivin with chemotherapeutic agents to enhance their therapeutic response while limiting the toxicity and side-effects. Citation Format: Umesh T. Sankpal, Don Eslin, W. Paul Bowman, Jeffrey C. Murray, Irene Sanchez, Michelle Jones, Sagar Shelake, Yazmin Hernandez, Anmol Wadwani, Hassaan Patel, Ashni Dudhia, Riyaz M. Basha. Association of specificity protein 1 and survivin expression in medulloblastoma: Identifying effective therapeutic targets. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2467.