1. Department of Obstetrics and Gynecology, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China.
2. Department of Obstetrics and Gynecology, Guangyuan Traditional Chinese Medicine Hospital, Guangyuan, China.
3. Breast and Thyroid Surgical Department, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, China.
4. Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China.
5. Department of Internal Medicine, Hui Long-Ba Town Hospital, Chongqing, China.
6. Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
# These authors contributed equally to the work.
Given the heterogeneity of solid tumors, single-target CAR-T cell therapy often leads to recurrence, especially in ovarian cancer (OV). Here, we constructed a Tandem-CAR targeting two antigens with secretory activity (IL-12) to improve the effects of CAR-T cell therapy. Twenty coexpressed upregulated genes were identified from the GEO database, and we found FOLR1 (folate receptor 1) and MSLN (mesothelin) were specifically and highly expressed in cancer tissues and only 11.25% of samples were negative for both antigens. We observed an increased proliferation rate for these three CAR-T cells, and Tandem CAR-T cells could efficiently lyse antigen-positive OV cells in vitro and secrete higher levels of cytokines than single-target CAR-T cells. More importantly, in vivo experiments indicated that Tandem CAR-T cells markedly decreased tumor volume, exhibited enhanced antitumor activity, and prolonged mouse survival. Furthermore, the infiltration and persistence of T cells in the Tandem-CAR group were higher than those in the MSLN-CAR and Control-T groups but comparable to those in the FOLR1-CAR group. Collectively, this study demonstrated that Tandem CAR-T cells secreting IL-12 could enhance immunotherapeutic effects by reducing tumor antigen escape and increasing T cell functionality, which could be a promising therapeutic strategy for OV and other solid tumors.
Keywords: ovarian cancer, CAR-T therapy, FOLR1, MSLN, IL-12