靶向SOAT1增强NK细胞介导的高级别浆液性卵巢癌细胞毒作用

Rationale: Despite advances in surgery and chemotherapy, high-grade serous ovarian cancer (HGSOC) still carries poor long-term survival, and most patients with advanced disease suffer relapse. Tumor cells exploit cholesterol metabolism, and the enzyme sterol O-acyltransferase 1 (SOAT1/ACAT1), which converts free cholesterol to cholesteryl esters, has emerged as a potential driver of tumor progression and immune evasion. NK cell degranulation, widely monitored via CD107a surface expression, provides a readout of NK cytotoxicity. We sought to identify genes whose loss enhances NK-mediated killing of HGSOC cells. Methods: We implemented a whole-genome CRISPR/Cas9 screen in OVCAR8 HGSOC cells challenged with allogeneic primary NK cells at an effector:target ratio. Relative guide RNA abundance was measured by next-generation sequencing before and after co-culture to identify genes whose disruption decreased tumor cell survival. Candidate negative genes were prioritized using filters: (1) ovarian cancer DepMap CERES score > -0.3 to avoid highly fitness-essential genes; (2) removal of curated core-essential genes; (3) at least three effective sgRNAs exhibiting consistent depletion; and (4) higher expression in ovarian cancer compared with normal ovary in public transcriptomic cohorts. SOAT1 emerged from this pipeline and was taken forward. OVCAR8 cells were transfected with SOAT1 siRNA and then co-cultured with NK92 cells. Tumor viability was quantified using metabolic/viability assay, while NK92 activation was evaluated by CD107a staining and flow cytometry. To assess clinical relevance, we interrogated independent ovarian cancer datasets (GSE118828, GSE26712) for relationships between SOAT1 expression, NK-related transcriptional signatures, and overall survival. Results: The CRISPR screen pinpointed SOAT1 as a top metabolic modifier of NK-mediated tumor clearance. SOAT1 silencing produced mRNA knockdown in OVCAR8 and significantly reduced tumor cell survival under NK92 attack, with median viability falling to 50-60% of control conditions. NK92 cells co-cultured with SOAT1-deficient OVCAR8 exhibited increased CD107a surface expression, indicating augmented degranulation and effector activity. Across public datasets, SOAT1 expression was elevated in ovarian tumors versus normal and adjacent tissues and aligned positively with transcriptional scores of NK infiltration and cytotoxic function. Notably, in cases with high NK infiltration, patients with higher SOAT1 expression experienced worse overall survival. Conclusions: By integrating genome-wide CRISPR screening with functional and bioinformatic analyses, we identify SOAT1 as a cholesterol-metabolic regulator that attenuates NK cell cytotoxicity in ovarian cancer. These findings nominate SOAT1 inhibition as an approach to metabolically reprogram HGSOC and improve the efficacy of NK-directed immunotherapies.