ID #144 Intranasal Delivery of PDGFRA-Targeted Immunoliposome SN-38 in H3K27-altered Diffuse Midline Glioma
Eita Uchida, Jun Watanabe, Kentaro Mineji, Savneet Kaur, Katerina Petrosky, Yasuhide Makino, Daichi Hagita, Yuji Kibe, Jiawei Huo, Manabu Natsumeda, Tomonari Suzuki, Peeng Zhang, Rintaro HashizumeAbstract
Diffuse midline glioma (DMG) is the most lethal pediatric brain tumor, with a median survival of less than 12 months. The blood-brain barrier (BBB) severely limits systemic drug delivery. Intranasal delivery (IND) bypasses the BBB, and immunoliposome (iLS) formulations enable receptor-targeted delivery to tumor cells while minimizing toxicity to normal tissues. This study developed and validated an IND strategy using PDGFRA-targeted immunoliposomes encapsulating SN-38 (PDGFRA-iLS-SN38) for selective DMG therapy.PDGFRA expression was assessed in DMG cell lines by Western blot, DIPG007 (PDGFRA-high) and SF8628 (PDGFRA-low) cells were selected for comparison. Cellular uptake of rhodamine-labeled PDGFRA-iLS was quantified by fluorescence microscopy. Anti-proliferative effects were measured using MTS viability, colony formation, BrdU incorporation, and Annexin V apoptosis assays. DNA damage (γH2AX, cleaved PARP) and DNA repair (BRCA1, RAD51) markers were analyzed by Western blot and immunocytochemistry. In vivo efficacy was evaluated in orthotopic DMG patient-derived xenograft (PDX) models using bioluminescence imaging and survival analysis.PDGFRA-iLS exhibited significantly enhanced cellular uptake in DIPG007 cells compared to non-targeted liposomes (LS), whereas minimal differential uptake was observed in SF8628 cells. In DIPG007 cells, PDGFRA-iLS-SN38 demonstrated greater anti-proliferative effects than LS-SN38, as evidenced by reduced cell viability and colony formation, suppression of S-phase progression, and increased apoptosis. PDGFRA-iLS-SN38 upregulated DNA damage markers (γH2AX, cleaved PARP) while downregulating DNA repair markers (BRCA1, RAD51) in DIPG007 cells.In orthotopic PDX models, IND of PDGFRA-iLS-SN38 significantly suppressed tumor growth and prolonged survival in PDGFRA-high DMG models compared to LS-SN38. Immunohistochemical analysis further revealed reduced Ki-67 proliferation and increased TUNEL-positive apoptosis in PDGFRA-high DMG models treated with PDGFRA-iLS-SN38.