Abstract 1168: Cathelicidin is a novel mediator of cancer immune surveillance

Cathelicidins are evolutionarily conserved anti-microbial peptides that have been identified in several epithelial tissues and a wide variety of immune cells. These peptides display multiple host-defense activities, as well as documented but underexplored antitumor activity. Using the regressor MCA sarcoma system as a model of immune mediated tumor rejection, we observed that deficiency in cathelicidin in cnlp-/- mice impaired the rejection of multiple regressor cell lines. Cnlp-/- mice also developed spontaneous lymphoma with age, thus confirming in a separate model system the requirement for cathelicidin in tumor immune surveillance. To decipher the immune defect that may engender impaired tumor surveillance, macrophages from cnlp-/- versus wild type (wt) mice were examined. Interestingly, cnlp-/- macrophages were defective in polarizing towards an antitumor M1 phenotype and less potent at phagocytosing target tumor cells. Altogether, these preliminary data suggest a crucial role of cathelicidin in limiting tumor formation and progression. Future experiments will define the role of cathelicidin in tumor surveillance mediated by macrophages and potentially other innate cells that also express cathelicidin, such as neutrophils and natural killer cells. Citation Format: Emilie T. Gross, Carlos D. Peinado, Isis G. Perez, Samaneh Keshavarz, Jack D. Bui. Cathelicidin is a novel mediator of cancer immune surveillance. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1168. doi:10.1158/1538-7445.AM2014-1168