AUTHOR=Robles-Planells Claudia , Michelson Sofia A. , Mena Javier , Escrig Daniela , Rojas Juan L. , Sanchez-Guerrero Giselle , Hernández Ronny , Barrera-Avalos Carlos , Rojo Leonel E. , Sauma Daniela , Kalergis Alexis M. , Imarai Mónica , Fernández Ricardo , Robles Carolina A. , Leiva-Salcedo Elías , Santander Rocio , Escobar Alejandro , Acuña-Castillo Claudio TITLE=Lithraea caustic (Litre) Extract Promotes an Antitumor Response Against B16 Melanoma JOURNAL=Frontiers in Pharmacology VOLUME=10 YEAR=2019 URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2019.01201 DOI=10.3389/fphar.2019.01201 ISSN=1663-9812 ABSTRACT=

Melanoma immunotherapy, specifically the autotransplant of dendritic cells charged with tumors antigens, has shown promising results in clinical trials. The positive clinical effects of this therapy have been associated to increased Th17 response and delayed-type hypersensitivity (DTH) against to tumor antigens. Some synthetic compounds, such as diphenylcyclopropenone (DPCP), are capable of triggering a DTH response in cutaneous malignancies and also to induce clinically relevant effects against melanoma. In this work, we evaluated Litre extract (LExT), a standardized extract of a Chilean stinging plant, Lithraea caustic (Litre). As Litre plant is known to induce DTH, we used a murine B16 melanoma model to compare the topical and intratumor efficacy of LExT with synthetic DTH inducers (DPCP and 2,4-dinitrochlorobenzene [DNCB]). LExt contained mainly long chain catechols and sesquiterpenes. The intratumor injection of LExT induced a significant delay in tumor growth, similarly topical treatment of an established tumor with 0.1% LExT ointment induced a growth delay and even tumor regression in 15% of treated animals. No significant changes were observed on the T-cell populations associated to LExT treatment, and neither DNCB nor DPCP were capable to induce none of the LExT-induced antitumoral effects. Interestingly, our results indicate that LExT induces an antitumor response against melanoma in a mouse model and could bring a new –and affordable- treatment for melanoma in humans.