Abstract 4638: Integrated proteogenomic characterization of longitudinal glioblastoma

Abstract Glioblastoma multiforme (GBM) is the most aggressive form of primary brain tumor, with no curative treatment options and median patient survival time of almost one year. Despite multi-modal therapy including surgery, irradiation and chemotherapy, all patients experience tumor progression and recurrence. Our group proposed and validated the first single cell guided functional classification of primary GBM in four tumor-intrinsic cell states which informed clinical outcome and delivered therapeutic options. However, recurrent GBM remains therapeutically unresolved due in part to the diffusely invasive nature and in part to marked cellular heterogeneity of the tumor.The evolutionary trajectory of glioblastoma after therapy is a multifaceted biological process that extends beyond discrete genetic alterations alone. Here, we profiled by multi-omics platforms the largest dataset of matched primary and recurrent GBM including 123 longitudinal glioblastoma pairs, temporally separated by standard-of-care treatment. Genomics, proteomics, and phosphoproteomics all independently captured the loss of proliferative-progenitor characteristics and a significant upregulation of specialized neuronal and synaptic signaling programs in recurrent GBM. Proteomic and phosphoproteomic analyses revealed that the molecular transition from proliferative to neuronal state at recurrence is marked by coherent post-translational activation of the WNT/PCP signaling pathway and the BRAF protein kinase. Multi-omic analysis of Patient-Derived Xenograft (PDX) models mimicked the patterns of evolutionary trajectory, consisting of marked activation of neuronal signaling programs in recurrent patients. Inhibition of the BRAF kinase with small molecule inhibitors impaired both neuronal transition and migration capability of recurrent glioblastoma cells, which are the phenotypic hallmarks of glioblastoma progression after therapy. Accordingly, combinatorial treatment of temozolomide with BRAF inhibitor, vemurafenib, significantly prolonged the survival of mouse PDX models. This work provides comprehensive insights into the biological mechanisms of glioblastoma evolution and treatment resistance and highlights new therapeutic opportunities to effectively counter them in the clinic. Citation Format: Simona Migliozzi, Kyung-Hee Kim, Harim Koo, Jun-Hee Hong, Seung Min Park, Hyung Joon Kwon, Luciano Garofano, Young Taek Oh, Fulvio D'Angelo, Chan Il Kim, Anna-Luisa Di Stefano, Franck Bielle, Jinlong Yin, Marc Sanson, Do-Hyun Nam, Jason K. Sa, Anna Lasorella, Jong Bae Park, Antonio Iavarone. Integrated proteogenomic characterization of longitudinal glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4638.