47 A CTS approach to golden allies: Merging adoptive cell therapy and nanotechnology in the fight against brain tumors

Objectives/Goals: Our lab’s novel adoptive cellular therapy (ACT) significantly improves survival in brain tumor models. However, there is a lack of biomarkers to assess immunotherapy responses. Our objective is to use gold nanorods to track hematopoietic stem cell migration, a critical arm of ACT, and validate it as a prognostic biomarker. Methods/Study Population: Hematopoietic stem cells (HSCs) were isolated from the bone marrow of 6-week-old C57BL/6J mice and co-cultured with varying gold nanorod (GNR) concentrations and time points. GNR uptake in HSCs was evaluated with inductive coupled plasma mass spectrometry, two-photon luminescence, and tissue histology. After GNR co-culture, HSC viability and differentiation were quantified with flow cytometry and colony forming unit assays. To evaluate the impact of GNRs on HSC reconstitution, mice received myeloablative total body irradiation and intravenously received GNR-labeled HSCs. Computed tomography (CT) contrast of GNRs will be confirmed through microCT. Lastly, mice will intracranially receive KR158b glioma and GNR-labeled HSC bio-distribution will be measured after ACT and correlated with survival outcomes. Results/Anticipated Results: We have demonstrated that GNRs are readily taken up by HSCs within 30 minutes, and retained within intracellular compartments, via TPL. Incubation of GNRs with HSCs did not significantly alter cell viability or differentiation, supporting the GNR’s favorable biosafety profile. Colony-forming unit assays revealed that GNR incubation did not significantly disrupt the total number of colonies formed and qualitatively, colonies did not demonstrate significant lineage differences. GNR-labeled HSCs demonstrated significant reconstitution after myeloablative total body irradiation in mice. We expect that GNR-labeled HSCs will distribute to the glioma microenvironment and draining lymph nodes, positively correlating with long-term survival after ACT. Discussion/Significance of Impact: GNRs harbored high biosafety and feasibility for tracking HSC migration after ACT. We seek to translate this theranostic tool into the current first-in-human clinical trials at our institution for patients diagnosed with neuroblastoma and diffuse intrinsic pontine glioma to improve immunotherapies against brain malignancies.