Abstract 516: The role of clathrin-mediated endocytosis of EGFR in glioblastoma cell viability and cell cycle progression

Abstract Glioblastoma (GBM) is characterized by poor prognosis and overexpression of epidermal growth factor receptor (EGFR). EGFR signaling is regulated through endocytosis, including clathrin-mediated endocytosis. We hypothesized that clathrin-mediated EGFR endocytosis promotes GBM cell viability and proliferation. Analysis of patient data from the Gliovis database revealed decreased overall survival in GBM patients with above-median clathrin expression (n=262) compared to below-median expression (n=263, p0. 05). Immunocytochemistry and Western blot analysis confirmed increased clathrin levels in GBM patient samples compared to normal brain tissue (n=15, p0. 01). To determine the functional effect of inhibiting clathrin-mediated endocytosis, U87 and U251 GBM cells were treated with 15 μM Pitstop-2, a clathrin inhibitor, for 24 hours. Pitstop-2 significantly reduced clathrin levels and cell viability by 40% compared to control (p0. 001, n=3). Cell cycle analysis by flow cytometry revealed Pitstop-2 treatment led to G2/M arrest in both cell lines versus control (p0. 01, n=3). Together, these findings indicate clathrin-mediated endocytosis of EGFR may promote GBM cell viability and proliferation. Further studies on the effects of clathrin inhibition on EGFR signaling and tumor growth in vivo will elucidate the therapeutic potential of targeting this pathway. Citation Format: Aaron Deter, Andrew J. Tsung, Maheedhara R. Guda, Swapna Asuthkar, Kiran Velpula. The role of clathrin-mediated endocytosis of EGFR in glioblastoma cell viability and cell cycle progression 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 (6Suppl): Abstract nr 516.