Anales RANF

P.73 P2X7 RECEPTOR INFLUENCES METASTATIC POTENTIAL AND VESICULAR RELEASE IN MELANOMA A. Pegoraro 1 , E. De Marchi 1 , E. Orioli 1 , F. Di Virgilio 1 , E. Adinolfi 1 1 . University of Ferrara, Ferrara, Italy. Metastatic melanoma is still a clinical challenge and new targeted drugs and therapeutic approaches are needed. It was already demonstrated that the administration of P2X7 antagonists in an in vivo model of melanoma reduced cancer growth suggesting P2X7 as a potential therapeutic target for this disease. We investigated the expression of P2X7 in commercially available melanoma specimens by immune-histochemical and RT-PCR analysis. Moreover, the metastatic potential of SK-MEL-28 and MA-MEL-19, two human melanoma cell lines expressing P2X7, was tested in in vitro scratch and soft agar assays after treatment with P2X7 antagonists AZ10606120 and A740003. Finally, in an effort to identify the mechanisms activated by P2X7 in metastatic melanoma, we studied release of vesicles from SK-MEL-28 and MA-MEL-19 following stimulation with the agonists ATP and BzATP. Data obtained from immunohistochemistry show increased P2X7 expression in metastatic melanoma patients. Moreover, mRNA expression of P2X7A and B was higher in stage IV melanomas that spread in lung and distant organs than stage III and stage IV with skin metastasis. These data suggest a role for P2X7 isoforms in melanoma dissemination. P2X7 antagonists treatment reduced in vitro migration and invasion capacity of SK-MEL-28 and MA-MEL-19. Interestingly, these cell lines released vesicles when stimulated with P2X7 agonists ATP and BZATP. To our knowledge this is the first demonstration of P2X7 mediated vesicles released from cancer cells. These preliminary data suggest a possible role of P2X7 in melanoma metastasis possibly due to vesicles release and make P2X7 a potential pharmacological target for advanced melanoma treatment.