ULK1 promotes metastatic progression in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is a leading cause of gynecological cancer mortality, driven largely by late diagnosis and chemo-resistant disease. While autophagy plays a critical role in the survival of EOC spheroids during metastasis, the role of ULK1, a key regulator of autophagy, in EOC progression remains unclear. To investigate this, we utilized CRISPR/Cas9 technology to delete ULK1 in EOC cell lines OVCAR8 and HEYA8, and the immortalized fallopian tube epithelial cell line FT190. Immunoblotting confirmed ULK1 loss and its associated autophagy disruption in EOC spheroids, evidenced by reduced Beclin-1 phosphorylation, impaired LC3 processing, and p62 accumulation. Culture-based assays revealed that ULK1 knockout decreased EOC spheroid cell viability due to increased apoptosis and, notably, impaired matrix-bound organoid growth, offering new insights into the potential role of ULK1 in affecting EOC tumor growth and spread. These findings were further demonstrated by in vivo xenograft models, in which ULK1 loss significantly reduced tumor burden and metastatic potential. The potential for ULK1 requirement in metastatic properties was supported by diminished invasive capacity of ULK1 knockout spheroid cells in mesothelial clearance assays. To investigate the mechanisms by which ULK1 contributes EOC tumor progression and metastasis, we conducted proteomic analyses of OVCAR8 spheroids, which revealed that ULK1 loss disrupted critical signaling pathways, including MEK-MAPK, PI3K-AKT-mTOR, and apoptosis regulation. Although ULK1 knockout failed to synergize with standard-of-care chemotherapeutics, it significantly enhanced sensitivity to MEK and mTOR inhibition, revealing potential therapeutic combinations to target autophagy via ULK1 and MAPK and PI3K-AKT-mTOR pathway vulnerabilities in EOC. Overall, this study highlights ULK1 as a critical regulator of multiple steps of EOC growth and metastasis, underscoring its potential as a novel therapeutic target in advanced ovarian cancer.