10247-ET-8 HHYPOXIA-TARGETING RADIOPHARMACEUTICAL 64CU-ATSM FOR PET MONITORING WITH LOCAL THERAPY IN HIGH-GRADE GLIOMA PATIENT-DERIVED XENOGRAFT MODEL

Abstract High-grade gliomas (HGGs) are highly aggressive brain cancers characterized by the presence of hypoxia within a rapidly-growing tumor mass. Due to invasion to the surrounding brain parenchyma, these tumors commonly recur locally,, and novel local approaches are required. Here, we show a positron emission tomography (PET) integrated local therapy (PETx), to target HGGs. This technique consists of a one-step local theranostic application, followed by PET monitoring, with a hypoxia-targeting radiopharmaceutical64Cu-diacetyl-bis (N4-methylthiosemicarbazone) (64Cu-ATSM). We examined the safety and therapeutic potential of 64Cu-ATSM PETx for HGG patient-derived xenograft (PDX) tumors. PDX models were recapitulated the parent tumor phenotype of high expression of HIF-1 alpha and BNIP3, biomarkers of tissue hypoxia. We confirmed that HIF-1 alpha and BNIP3 were highly upregulated under hypoxia and 64Cu-ATSM was retained with potent cytotoxic effect under hypoxic condition in vitro. We determined that determined the maximum tolerated dose (MTD) to be 3.7 MBq in mouse. PETx using the MTD dose of 64Cu-ATSM indicated high tumor penetration, distribution, and retention of 64Cu-ATSM in PDX tumors, as compared to sham-treated mice. The 64Cu-ATSM PETx promoted DNA double-strand breaks, followed by apoptosis in tumors, and extensively prolonged overall survival with tolerable systemic toxicity. These findings indicate the potential of 64Cu-ATSM PETx to induce high uptake in the hypoxic tumor microenvironment, and strong therapeutic effects in PDX models. These findings establish 64Cu-ATSM PETx as a potential novel theranostic approach to facilitate local control of HGGs.