Abstract 889: Metformin treatment inhibits proliferation and induces apoptosis in medulloblastoma cells

Abstract

Abstract Medulloblastoma is the most common malignant brain tumor in children that typically requires a patient specific combination of surgical resection, chemotherapy, and radiation. Up to 80% of medulloblastoma patients respond to treatment and survive long-term. However, survivors often suffer from severe long term sequelae secondary to treatment that affects their neurocognitive and growth potential. Therefore, there is an urgency to develop less toxic, more focused treatment strategies that target specific pathways or molecules involved in medulloblastoma development and progression. Metformin is a widely used non-toxic anti-diabetic drug that has mild, generally well-tolerated side effects. Studies have shown that it can reduce cancer risk and improve the prognosis of certain malignancies. However, the mechanism underlying its anti-cancer effect is still unclear and varies depending on the type of cancer. There are reports that metformin can target the specificity protein 1 (Sp1) transcription factor. Sp1 regulates the expression of a variety of proteins involved in regulation of cancer cell proliferation including survivin, an Inhibitor of Apoptosis Protein family member. Expression of survivin is increased in medulloblastoma cells and often correlates with poor prognosis. We studied the anti-cancer activity of metformin on medulloblastoma using DAOY and D283 cells. Metformin treatment resulted in a dose and time dependent reduction in cell proliferation in both cell lines. This growth inhibition was accompanied by the induction of apoptosis as determined by annexin-V staining, PARP cleavage, and activation of caspase3/7. Metformin also induced cell cycle arrest in G0/G1 phase. Western blot analysis using extracts from cells treated with metformin revealed that the anti-proliferative and apoptotic effects of metformin in medulloblastoma were accompanied by a reduction in the expression of survivin protein. Overexpression of survivin is reported to be associated with chemo- and radio-resistance. This study suggests the use of metformin as a novel anticancer agent in combination with standard therapy for the treatment of medulloblastoma. Citation Format: Kristen C. Payne, Abigail Hunter, W Paul Bowman, Jeffrey C. Murray, Riyaz Basha, Umesh T. Sankpal. Metformin treatment inhibits proliferation and induces apoptosis in medulloblastoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 889.