DDDR-35. TARGETING GBM INVASION BY INHIBITING KCNA1 WITH 4-AMINOPYRIDINE: AN FDA APPROVED DRUG THAT EASILY PASS THROUGH THE BBB

Abstract

Abstract Diffuse invasion is a hall mark of glioblastoma (GB) and one of the primary causes of poor clinical outcomes in GBM patients. Tumor cells migrate deep into the normal brain tissues are frequently protected by the BBB, making them particularly difficult to treat. New therapeutic targets are needed. Our previous studies using spatially dissected and functionally validated matching pairs of invasive and tumor core GBM cells identified KCNA1 as a shared gene that is selectively over-expressed in the invasive GBM cells in 6 patient derived orthotopic xenograft (PDOX) mouse models of pediatric GBM (Huang YL et al, Adv Science 2021). A subsequent analysis of adult GBM RNAseq data from IVY Atlas revealed a significantly elevated expression of KCNA1 (4.9 fold) in the invasive edges of patient GBM tumors. It is also one of the 11 core molecules identified in GEO and TCGA databases through an integrated bioinformatic analysis (Yang J, Front Onc 2021). To determine the anti-invasive activities of targeting KCNA1, we treated three highly invasive adult GBM PDOX models with 4-aminopyridine (4-AP), an old lipid soluble drug that easily penetrate the BBB, at 5 mg/kg, i.p., 5 days/week for 8 weeks acing alone or in combination with fractionated radiation (at 2 Gy/day x days). As single agent, 4-AP significantly extended median animal survival times in 1/3 GBM models (69 to 77 days, P = 0.033). Combination with XRT did not significantly improve the animal survival times in the three models. Systematic analysis of GBM invasion in mouse brains of the 3 PDOX models before, during and after 4-AP treatment revealed remarkable inhibition of tumor invasion. Our data highlighted the role of KCNA1 in promoting GBM invasion and support the fine tuning of 4-AP dose, schedule, and length of treatment to serve as a novel component of anti-GBM invasion therapies.