Abstract 1664: Inhibition of 4T1 mammary tumor growth in BALB/c mice by subcutaneous and intraperitoneal injection of a 4T1 whole cell vaccine containing IL-2 and GM-CSF as adjuvants

Developing animal tumor models for human cancer vaccines creates a tool to investigate the mechanism of action, variations in formulation, dosing schedules, and combinations with other forms of cancer therapy. In this study we developed a mouse whole cell mammary cancer vaccine model with both subcutaneous and intraperitoneal injection of the vaccine. The vaccine, containing 4T1 mouse mammary cancer cells (1,000,000 cells), IL-2 (0.2 µg) and GM-CSF (0.1 µg) in a total volume of 150 µl, was injected either subcutaneously into the backs of BALB/c mice or intraperitoneally. There were six injections of the vaccine (weeks 1, 2, 3, 7, 11, 15) and one week after the last injection 100,000 4T1 cells from cell culture in a volume of 100 µl were injected into the scapular region of the mice. At 22 days post 4T1 tumor transplantation there was a 37% inhibition of the growth of the 4T1 tumor in the mice receiving the subcutaneous injection of the vaccine and a 42% inhibition of the growth of the 4T1 tumor in the mice receiving the intraperitoneal injection of the vaccine. The inhibition of 4T1 mammary tumor growth in this mouse model with subcutaneous injection of a whole cell vaccine gives further support for the previously reported efficacy in a Phase 1/2 clinical trial of our therapeutic breast cancer vaccine containing autologous and allogeneic breast cancer cells in the adjuvant setting. The inhibition of 4T1 tumor growth with intraperitoneal injection suggests a delivery method that may be applicable to ovarian cancer and cancer patients with malignant ascites. Citation Format: Jonathan F. Head, Jeffrey T. Phillips, Xianpeng Jiang, Robert L. Elliott. Inhibition of 4T1 mammary tumor growth in BALB/c mice by subcutaneous and intraperitoneal injection of a 4T1 whole cell vaccine containing IL-2 and GM-CSF as adjuvants [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1664. doi:10.1158/1538-7445.AM2017-1664