Siddiqui, M. Y. | Search bioRxiv

bioRxiv2025

Cholesterol metabolism modulation facilitates CAR-T induced killing of ovarian cancer

Ovarian cancer is one of the most lethal gynecological cancers worldwide and has one of the highest recurrence rates. Recently developed Chimeric Antigen Receptor T (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 explored 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 found an altered cholesterol metabolism, featured by increased storage of cholesteryl ester in lipid droplets and free cholesterol, in ovarian cancer cells that survived the CAR-T treatment. Administration of Avasimibe, an inhibitor of cholesteryl esterification, further enhanced CAR-T cytotoxicity. Our study shows the promise of implementing metabolic modulation to facilitate CAR-T cell treatment of solid tumors. Significance StatementOvarian cancer is a major global health challenge, mainly due to relapse driven by chemotherapy resistance development. Meanwhile, immunotherapies such as CAR-T have revolutionized treatment for blood cancers, but their application in solid tumors like ovarian cancer is hindered by limited efficacy. This study uses high-content stimulated Raman scattering (SRS) imaging to reveal metabolic adaptations that help ovarian cancer cells survive CAR-T-mediated cytotoxicity. Guided by these insights, we apply metabolic interventions that enhance CAR-T cytotoxicity efficacy. This approach reveals therapeutic vulnerabilities in ovarian cancer and demonstrates an investigative strategy applicable for overcoming resistance in solid tumors.

cell biology↗

bioRxiv2024

Tunable Universal OR-gated CAR T cells for AML

Abstract/SummaryAcute myeloid leukemia (AML) is a hematopoietic malignancy characterized by antigen heterogeneity and poor prognosis. A potential therapeutic approach to address this heterogeneity is targeting multiple surface antigens to prevent antigen escape and relapse. Chimeric antigen receptor (CAR) T cells are an adoptive cell therapy that have demonstrated remarkable clinical success in the treatment of B cell malignancies, and many efforts are underway to adapt them to myeloid malignancies. To tackle the heterogeneity of AML, logically targeting multiple antigens through an "A OR B" gated CAR circuit would be desirable. Here we combined FLT3 antigen targeting with the well characterized CD33 myeloid marker as a combinatorial OR gate approach using our split, universal, programmable (SUPRA) CAR platform. The split platform affords tunability over activation levels and multiplexed targeting that cannot be achieved through a tandem bispecific approach. We systematically characterized the specificity and sensitivity of different SUPRA CAR adapters against each target individually and in combination against a panel of target cell lines. Our results demonstrate that this CAR system can effectively target two antigens with equivalent efficacy to conventional CARs while reducing the engineering burden associated with designing CAR T cells against multiple antigens. Furthermore, we can characterize an effective dose range where off-target cytotoxicity against hematopoietic stem and progenitor cells is minimized. With the recent clinical advances in universal CAR designs, our SUPRA OR gate has the potential to provide an effective and safer solution to treating AML.

synthetic biology↗