Triple negative breast cancer (TNBC) is a complex and aggressive subtype of breast cancer lacking estrogen receptor, progesterone receptor, and HER2 amplifications; making it difficult to target therapeutically. Consequently, there’s a constant demand for better treatment options for TNBC. To help address the need for TNBC models, we highlighted the EMT6 model last month and herein we put forth the E0771 model, another TNBC syngeneic model for use in preclinical immuno-oncology. The E0771 cell line is a spontaneously developing medullary breast adenocarcinoma from C57BL/6 mice. Parental E0771 is poorly metastatic when compared to 4T1 and has homozygous mutations in the Trp53 and KRAS genes.
In this spotlight, we present data from our initial growth and efficacy studies with the E0771 model. The data presented here provides an overview of the E0771 cell line’s response to immuno-oncology agents and radiation therapy to enable design of rational combination studies.
Tumor growth kinetics for the E0771 model is shown in Figure 1. The median doubling time is ~5-6 days with a steady increase in tumor volume with no apparent tumor related body weight loss. The growth rate allows for a three-week therapeutic window to evaluate anti-tumor responses. The growth parameters of untreated tumors and isotype control (Rat IgG2b) treated tumors are similar (Fig. 1).