Targeted PDT, a novel way to induce immunoactivating properties and stimulate anti-tumoral immune response: Illustration in human Pancreatic Adenocarcinoma and Peritoneal Ovarian Cancer models

Otherwise, the use of Photodynamic Therapy (PDT), based on the use of a photosensitizer (PS) and a light with a specific wavelength, has already proved its worth and has prompted a growing interest in the field of oncology. The combination of these factors will generate cytotoxic reactive oxygen species capable of inducing cancer cell death and very importantly, to close the tumor-associated vasculature and trigger the host immune system. More specifically, the damage induced by the PDT generates various alarm signals that could be detected by effectors of innate and adaptative immunity. Nevertheless, the effect of PDT on the regulation of the immune system remains poorly investigated. Although PDT appears to be more selective than other cancer treatment procedures, cancers such as pancreatic adenocarcinoma (ADKP) and intraperitoneal ovarian cancers (OVC) are more problematic and, therefore, the PS used must be much more selective for these tumors. Our previous study described the specificity of a new patented PS coupled with folate receptor (FR) and capable of targeting specifically cancer cells which overexpresses FR. In this context, the aim of this study was (i) to evaluate in vitro and in vivo the efficacy of this new-patented photosensitizer on ADKP and ovarian cancer, which expressed FR in 100% of ADKP and OVC or over-expressed in almost 50% of cases and (ii) to analyze the consequences of this treatment on the regulation of the human immune cells (PBMC).