Endoplasmic reticulum targeting tin porphyrins with oligoethyleneglycol chains: synthesis, DFT studies and anti-cancer activities

Abstract

The A2B2 and A3B type porphyrins and their tin(IV) complexes are reported bearing two or three oligoethyleneglycol (OEG) chains at the meso‑positions. The other meso‑positions of tin(IV) porphyrins were substituted with N-butylcarbazole and triphenylamine moieties. The structures of all eight porphyrins were confirmed by IR, NMR and MALDI-mass; their UV–vis absorption, fluorescence properties were also analysed. The cellular uptake and anti-cancer activities of four tin porphyrins were examined in lung cancer cells. The presence of three OEG chains enhanced their cell permeability and bioactivity against cancer cells. A3B type tin porphyrins with three OEG chains displayed endoplasmic reticulum (ER) colocalization and generated ROS after light exposure as judged by confocal microscopy. The in-vitro photocytotoxicity studies revealed excellent IC50 values between 0.76 to 1.36 μM for A3B type porphyrins. Furthermore, these porphyrins were non-toxic in dark conditions, suggesting their potential as PDT agents for cancer treatment in near future.