Authors: Liang Hu, Shiming Zhang, John Sienkiewicz, Hua Zhou, Robert Berahovich, Jinying Sun, Michael Li, Adrian Ocampo, Xianghong Liu, Yanwei Huang, Hizkia Harto, Shirley Xu, Vita Golubovskaya, and Lijun Wu
Abstract
The human epidermal growth factor receptor 2 (HER2) is a transmembrane tyrosine kinase receptor and tumor-associated antigen abnormally expressed in various types of cancer, including breast, ovarian, and gastric cancer. HER2 overexpression is highly correlated with increased tumor aggressiveness, poorer prognosis, and shorter overall survival. Consequently, multiple HER2-targeted therapies have been developed and approved; however, only a subset of patients benefit from these treatments, and relapses are common. More potent and durable HER2-targeted therapies are desperately needed for patients with HER2-positive cancers. In this study, we developed a lipid nanoparticle (LNP)-based therapy formulated with mRNA encoding a novel HER2-CD3-Fc bispecific antibody (bsAb) for HER2-positive cancers. The LNPs efficiently transfected various types of cells, such as HEK293S, SKOV-3, and A1847, leading to robust and sustained secretion of the HER2-CD3-Fc bsAb with high binding affinity to both HER2 and CD3. The bsAb induced potent T-cell-directed cytotoxicity, along with secretion of IFN-λ, TNF-α, and granzyme B, against various types of HER2-positive tumor cells in vitro, including A549, NCI-H460, SKOV-3, A1847, SKBR3, and MDA-MB-231. The bsAb-mediated antitumor effect is highly specific and strictly dependent on its binding to HER2, as evidenced by the gained resistance of A549 and A1847 her2 knockout cells and the acquired sensitivity of mouse 4T1 cells overexpressing the human HER2 extracellular domain (ECD) or epitope-containing subdomain IV to the bsAb-induced T cell cytotoxicity. The bsAb also relies on its binding to CD3 for T-cell recruitment, as ablation of CD3 binding abolished the bsAb’s ability to elicit antitumor activity. Importantly, intratumoral injection of the HER2-CD3-Fc mRNA-LNPs triggers a strong antitumor response and completely blocks HER2-positive tumor growth in a mouse xenograft model of human ovarian cancer. These results indicate that the novel HER2-CD3-Fc mRNA-LNP-based therapy has the potential to effectively treat HER2-positive cancer.
Fig. Intratumoral injection of HER2-CD3-Fc mRNA-LNPs induces a strong antitumor response in an NSG mouse ovarian cancer xenograft model. (A–G) A total of 2 × 106 A1847 cells were inoculated into NSG mice subcutaneously (s.c.) on day 0 of the study, then 20 μL of PBS, GFP mRNA-LNPs (containing 1 μg mRNA), or HER2-CD3-Fc mRNA-LNPs (containing 1 μg mRNA) were injected intratumorally (i.t.) on days 7, 14, and 21. On day 9, 1 × 107 human T cells were injected intravenously (i.v.). The tumor sizes were measured with calipers and used to calculate tumor volume with the formula (width2 × length)/2. The tumor volumes (B,C) and mouse body weights (D) were monitored and recorded every three days. Blood samples were collected at the end of the study and tested for toxicology biomarkers alanine aminotransferase (ALT) (E), aspartate aminotransferase (AST) (F), and amylase (G). Each line in (B) represents a tumor. Data are presented as the means ± SD in (C,D). N.S., not significant; ****, p < 0.0001.
Selected Figures
Keywords: HER2; cancer; bispecific antibody; CD3; lipid nanoparticle; immunotherapy; Flex-S
Vaccines 2024, 12(7), 808