A functional comparison of two transplantable syngeneic mouse models of melanoma: B16F0 and YUMM1.7

Abstract

The B16 murine melanoma cell lines are considered the gold standard for testing melanoma immunotherapies due to low treatment success rates. However, the clinical relevance of these models has been questioned due to a mutational landscape void of driver mutations typically seen in human melanomas and a tendency to form necrotic cores at high tumor volumes. Creating the YUMM1.7 line addressed these limitations by providing an additional contextually consistent model with a more clinically relevant genetic background. The combined use of both models can generate stronger studies in melanoma immunology and immunotherapy. However, to date, there have been no direct functional comparisons of the characteristics of these two models to inform the design of such studies. To address this, we conducted a series of functional experiments to characterize the kinetics of tumor growth, chemotherapeutic sensitivity, and immunogenicity of these models. We found that the B16F0 model had faster intrinsic tumor growth rates, was more susceptible to lysis by tumor-specific CD8+ T cells, and secreted higher levels of the angiogenic factors VEGF and Ang2. Meanwhile, the YUMM1.7 model was more sensitive to chemotherapeutic treatment, secreted higher levels of chemokines CCL2, CXCL1, and CX3CL1, and showed higher infiltration of lymphocyte and myeloid subsets at the same tumor size. Overall, YUMM1.7 model may be better suited for in vivo studies of mechanisms that require a wider observation window and intervention than the B16F0 model, such as immune response. However, angiogenesis and immunotherapy studies may benefit from a more in-depth comparative analyses of both models.