Abstract 1390: Dysregulation of microtubule dynamics caused by <i>LOXL3</i> knockout triggers mitosis catastrophe and senescence in U87MG and U251 cells

The amine oxidase LOXL3 has been implicated in tumor development and progression, with elevated expression in glioblastoma (GBM), the most malignant central nervous system tumor. This enzyme influences adhesion, migration, and proliferation of GBM cells. Furthermore, LOXL3 upregulation contributes to poorer GBM patient outcomes, and its expression is correlated with genes encoding tubulins. Microtubules, the major component of the cytoskeleton, are crucial for the cell cycle and mitotic progression. In this study, LOXL3 knockout was performed using CRISPR-Cas9 in two GBM cell lines, U87MG and U251, which resulted in decreased cell viability and migration in both cell lines. Transcriptome enrichment analysis revealed downregulation of genes associated with tubulin acetylation, which was subsequently confirmed by western blot and immunofluorescence analyses. Both U87MG and U251 cells exhibited downregulation of cell cycle- and proliferation-related genes. Functional assays confirmed that LOXL3-knockout cells exhibited delayed cell cycle progression and significant alterations in mitotic spindles during the metaphase-anaphase transition. Nuclear analysis revealed morphological changes indicative of mitotic catastrophe in U87MG cells (with wild-type TP53) and senescence in U251 cells (with mutated TP53). U87MG cells with LOXL3 knocked out presented increased apoptotic cells, which was enhanced after TMZ treatment. Our results suggest that LOXL3 is a potential therapeutic target for GBM treatment, especially in those with higher LOXL3 expression. LOXL3 inhibition can induce tumor cell senescence in GBM with TP53 mutation and apoptosis in cases with wild-type TP53 boosting TMZ treatment, improving GBM patients´ outcome. Citation Format: Talita de Souza Laurentino, Roseli da Silva Soares, Ricardo Cesar Cintra, Antonio Marcondes Lerario, Suely Kazue Marie, Sueli Mieko Oba-Shinjo. Dysregulation of microtubule dynamics caused by LOXL3 knockout triggers mitosis catastrophe and senescence in U87MG and U251 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1390.