Photodynamic antitumor activity of halogenated gallium(III) and phosphorus(V) corroles

Abstract

Four new phosphorus(V) and gallium(III) corrole complexes were prepared and evaluated as antitumor agents in photodynamic therapy (PDT) in vivo and vitro. All complexes showed low dark toxicity and good photocytotoxicity under light illumination (625 ± 2 nm, 3 W/m2). Especially, phosphorus(V) corrole (1-P) exhibited quite excellent photocytotoxicity with IC50 of 0.03 (±0.003) μM with phototoxic indices (p.i.) of >3333.33 against MDA-MB-231 tumor cells. Under light irradiation, 1-P could produce reactive oxygen species (ROS) in cells and destroy mitochondrial membrane potential, leading to apoptosis. The PDT treatment with 1-P arrested the cell at sub-G1 phase. Animal test showed 1-P could effectively inhibit the growth of MDA-MB-231 tumor cell grafted BALB/c nude mice. The PDT generated ROS might boost the anti-tumor immune response (e.g., CD3+, CD4+ and CD8+). It is well known that edible bird's nest (EBN) helps to improve the immune system and thus is beneficial to health. Photodynamic therapy combined with EBN (100 mg/kg) treatment was conducted for the first time to evaluate the possible antitumor synergistic effect in mice. It turned that EBN may do significant positive help in eliminating the tumors in PDT-treated mice by enhancing T cell expression as indicated by the detection of remarkable higher CD3+ expression in tumor and spleen tissue.