Abstract 2368: Intratumoral delivery of HER-2-CD3hFc mRNA-LNP inhibits ovarian tumor growth

Abstract Her-2 is a well-known driver of carcinogenesis that is overexpressed in breast, ovarian and other tumors. Immunotherapy with bispecific antibodies is a promising cancer therapy approach. Her-2 (Herceptin) antibody was used to test bispecific antibody against ovarian cancer cells. First, Her-2-CAR-T cells with Her-2 (4D5) ScFv and 4-1BB costimulatory domain were generated and tested using in vitro killing and IFN-gamma assays, and in vivo efficacy SKOV-3 xenograft NSG mouse model. Her-2-CAR-T cells killed SKBR-3 breast and SKOV-3 ovarian cancer cells and stopped SKOV-3 xenograft tumor growth. This Her-2-ScFv was used to generate bispecific Her-2 ScFv-CD3-ScFv human Fc antibody using in vitro transcribed mRNA. The 5’capped Her-2-CD3-hFc mRNA with 5’UTR, 3’UTR and poly A tail was generated by in vitro transcription using DNA template. The mRNA was embedded into lipid nanoparticles (LNP) using microfluidic PreciGenome Flex S NanoGenerator. Western blotting detected 160 kDa bispecific antibody secreted from A1847 and 293 cells transfected with mRNA-LNPs. The bispecific antibody was binding Her-2-positive A1847 ovarian cancer cell lines and T cells by FACS analysis. The Her-2-CD3-hFc bispecific antibody with T cells effectively killed Her-2-positive target cells in a dose-dependent manner in RTCA assay and produced high level of IFN-gamma. Moreover, intratumoral delivery of Her-2-CD3-hFc mRNA-LNP with intravenous injection of T cells completely blocked A1847 xenograft tumor growth. In conclusion. intratumoral delivery of Her-2-CD3 mRNA-LNP blocks ovarian xenograft tumor growth and provides a solid basis for future pre-clinical and clinical studies. Citation Format: Vita M. Golubovskaya, John Sienkiewicz, Jinying Sun, Shiming Zhang, Yanwei Huang, Liang Hu, Hua Zhou, Hizkia Harto, Shirley Xu, Robert Berahovich, Lijun Wu. Intratumoral delivery of HER-2-CD3hFc mRNA-LNP inhibits ovarian tumor growth abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 2368.