Abstract 1276: UV radiation interacts with Endothelin 3 and loss of nucleotide excision repair pathway to promote melanomagenesis.

Melanomagenesis is influenced by the interaction of environmental (such as UV radiation) and genetic factors. The Xpa gene is important in the Nucleotide Excision Repair (NER) pathway. Similar to humans afflicted with Xeroderma Pigmentosum, which results from mutations in genes that play a role in NER, Xpa deficient mice show high sensitivity to UV light, leading to skin cancer development. However, Xpa deficient mice do not develop melanoma even upon UV exposure. The Endothelin 3 (Edn3) signaling pathway is essential for proliferation, survival and migration of melanocyte precursor cells. In humans, this pathway has also been implicated in melanoma progression and its metastatic potential. The purpose of this study is to develop a UV induced melanoma mouse model that combines Xpa deficiency with the over-activation of the Edn3 pathway. To this end, transgenic mice over-expressing Edn3 under the control of the keratin 5 promoter (K5-Edn3) and carrying a targeted mutation in Xpa were exposed to a single suberythemal neonatal dose of UV radiation. A subgroup of mice was also exposed to a second dose of UV radiation at 6 weeks of age. Histomorphology and immunostaining were used to confirm the melanocytic origin of primary skin tumors and metastases. Melanoma was only found in animals with the K5-Edn3 transgene. High penetrance was observed in animals exposed to one dose of UV radiation that were Xpa null (100%, n=3) when compared to Xpa heterozygous (73%, n=11) or Xpa wild type (43%, n=7). Enlarged and hyperpigmented lymph nodes were present in animals with melanoma skin lesions and these were diagnosed as local metastases. These results indicate that UV radiation exposure, in conjunction with over-activation of the Edn3 pathway is sufficient to lead to melanomagenesis in mice. Citation Format: Ana Paula Benaduce, Deannys Batista, Gabriel Grilo, Karen Jorge, Lidia Kos. UV radiation interacts with Endothelin 3 and loss of nucleotide excision repair pathway to promote melanomagenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1276. doi:10.1158/1538-7445.AM2013-1276