High-Content SRS Imaging Unveils Altered Cholesterol Metabolism in Ovarian Cancers Under CAR-T Treatment.

Ovarian cancer is one of the most lethal gynecological cancers worldwide and has one of the highest recurrence rates. Recently developed Chimeric Antigen Receptor (CAR) -T cell therapy has shown potent clinical efficacy against hematological malignancies. However, solid tumors, including ovarian cancer, possess several mechanisms that hinder T cell activity, and metabolic alteration of cancer cells has been shown to contribute to resistance to immune cell attack against solid tumors. Here, we explore the metabolic response of ovarian cancer cells to CAR-T cell attack using label-free high-content hyperspectral stimulated Raman scattering (h2SRS) imaging. Utilizing visible h2SRS imaging with much improved spatial resolution, we find an altered cholesterol metabolism, featured by increased storage of cholesteryl ester in lipid droplets and free cholesterol, in ovarian cancer cells that survive the CAR-T treatment. Administration of Avasimibe, an inhibitor of cholesteryl esterification, further enhances CAR-T cytotoxicity. Our study shows the promise of implementing metabolic modulation to facilitate CAR-T cell treatment of solid tumors.