Abstract 5088: Silibinin inhibits UVB-induced promotion and progression of microscopic basal cell carcinoma formation via targeting bone morphogenic protein 2

Non-melanoma skin cancers (NMSCs) account for about half of all malignancies diagnosed annually in the United States. Around 80% of NMSCs are basal cell carcinoma (BCC) and 20% are squamous cell carcinoma (SCC). Whereas the efficacy of several chemopreventive agents has been examined and reported against both BCC and SCC, a majority of these studies have focused on the test agent’s activity in a long-term setting to determine the amount of tumors formed. Notably, the studies evaluating the efficacy of chemopreventive agents during early stage/s of BCC development are lacking. Accordingly, utilizing the well-established patched (Ptch)+/- mouse model of UVB-induced BCC formation, we excised skin samples from UVB exposed mice prior to tumor formation to study the promotion/progression of BCC and to determine the target/s of silibinin, a well-known skin cancer (SCC) chemopreventive agent, in tumor growth inhibition. Ptch+/- and Ptch+/+ mice were irradiated with UVB 240mJ/cm2 3 times per week with or without topically applied silibinin 5 times per week. As early as one month, we found that UVB exposure significantly increased the number of mast cells in Ptch+/- mice by about 48% (P Citation Format: Cynthia M. Rigby, Gagan Deep, Anil K. Jain, David J. Orlicky, Chapla Agarwal, Komal Raina, Rajesh Agarwal. Silibinin inhibits UVB-induced promotion and progression of microscopic basal cell carcinoma formation via targeting bone morphogenic protein 2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5088.