Cutaneous squamous cell carcinoma (cSCC), a form of non-melanoma skin cancer, is the second most common form of cancer in the United States, with over one million cases diagnosed annually. Tpl2 (MAP3K8) is a serine threonine protein kinase in the mitogen-activated protein kinase (MAPK) signal transduction cascade. Tpl2 was identified by our laboratory as having a tumor suppressive function in skin carcinogenesis, with Tpl2 knockout mice developing significantly more papillomas and squamous cell carcinomas than matched wildtype (WT) controls. Cellular mesenchymal to epithelial transition factor (c-Met) is a receptor heightened in malignant skin cancers and involved in Tpl2 signaling. When bound to its ligand, hepatocyte growth factor (HGF), c-Met can regulate cell proliferation, survival, angiogenesis and invasion. The aim of this study was to ascertain whether c-Met signaling contributes to the heightened skin tumorigenesis in Tpl2-/- mice. Forty-four WT and Tpl2 -/- mice were subjected to a two-stage chemical carcinogenesis protocol for one year to induce skin tumors. Starting at the time of promotion, half of the WT and Tpl2 -/- mice were placed on normal diet and half received diet plus 30mg/kg Capmatinib, a pharmacological inihibitor of c-Met. This diet continued for the duration of the study. No adverse health effects were found in Capmatinib-treated mice. Similar to what we previously reported, Tpl2 -/- mice developed tumors earlier than WT controls and had statistically higher tumor incidence and overall tumor burden than WT mice. The number of tumor bearing Tpl2 -/- and Tpl2 -/- + Capmatinib fed mice was similar, although Capmatinib fed mice had a 60% reduction in overall tumor burden. Studies are underway to determine if Capmatinib affected the frequency of malignant conversion in Tpl2 -/- mice. In summary, our studies demonstrate that heightened c-Met signaling contributes to the higher tumor formation in Tpl2-/- mice and should be evaluated further as a possible therapeutic target in Tpl2-related skin cancers.

Citation Format: Nicole F. Bonan, David Kowalski, Kaitlin Kudlac, Lauren G. Falkenberg, Erik Maradiaga, Kira Flaherty, Jonathan S. Wiest, Katie L. DeCicco-Skinner. Role of c-Met in the development and progression of Tpl2-related skin cancer [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 2809. doi:10.1158/1538-7445.AM2017-2809