495 DNA targeting autoantibody for brain tumor therapy

Objectives/Goals: Nucleoside transport by ENT2 facilitates transit of the lupus anti-DNA autoantibody Deoxymab into cells and across the blood–brain barrier into brain tumors. This work examines the Deoxymab-nucleoside interactions that contribute to membrane crossing and apply them in brain tumor therapeutics. Methods/Study Population: Deoxymab interactions with individual nucleosides, nucleobases, and pentose sugars are examined by surface plasma resonance (SPR) and cell penetration assays in a panel of cell lines including glioblastoma, breast cancer, and normal breast epithelial cells. Deoxymab-conjugated gold nanoparticles are generated and tested for binding to normal human astrocytes and glioma cells, and the impact of supplemental nucleosides on this binding is determined. Deoxymab-gold nanoparticles are tested for brain tumor localization by systemic and local administration in mice bearing orthotopic glioblastoma brain tumors and enhancement of laser interstitial thermal therapy (LITT) examined. Results/Anticipated Results: Individual nucleosides significantly increase the efficiency of cell penetration by Deoxymab in all cell lines tested. In contrast, component nucleobases and pentose sugars significantly suppress the uptake of the autoantibody into cells. Deoxymab-conjugated gold nanoparticles bind DNA in vitro and to astrocytes in culture and are anticipated will enhance the efficacy if LITT in vivo by associating with DNA released by necrotic tumors and/or by locally administered nucleosides in brain tumor environments and subsequently act as heat sink to amplify LITT impact. Discussion/Significance of Impact: Deoxymab is a DNA-targeting, cell-penetrating autoantibody. These findings establish nucleosides as the components of DNA that promote autoantibody membrane crossing through ENT2 activity and indicate potential for use of Deoxymab-gold nanoparticles in combination with LITT for brain tumor therapy.