Me-ALA based photodynamic therapy as a novel putative immunogenic cell death inducer against melanoma

LAMBERTI MJ; MENTUCCI FM; GATTI GA; MACCIONI M; RIVAROLA VA

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

The immunogenicity of tumor cells has recently been acknowledged as a critical determinant of efficacy in cancer therapy. It is now clear that cancer cells can succumb to some anticancer therapies by undergoing a peculiar form of cell death that is characterized by the emission of ?damage/associated molecular patterns? (DAMPs). The release of DAMPs and other immunostimulatory factors by cells dying through immunogenic cell death (ICD) favors the establishment of a productive interface with the immune system. The purpose of the present study was to evaluate the effectiveness of the PS protoporphyrin IX (PpIX) in promoting the exposure of pivotal DAMPs that characterize ICD, such as calreticulin (CRT), on melanoma cells. B16-OVA cells were sensitized with Me-ALA-induced PpIX during 4 h. Interestingly, confocal microscopy images showed that PpIX was preferentially localized in the endoplasmic reticulum (ER) prior to irradiation (Pearson´s r: 0.934). Subsequent photoactivation of PpIX with lethal dose significantly promoted oxidative stress (100% DCF + cells). ROS-scavenger N-acetylcysteine (NAC) inhibited cytotoxic effect of PDT by 33.3% (p