The photodynamic activity of 131-[2'-(2-pyridyl)ethylamine] chlorin e6 photosensitizer in human esophageal cancer.

A novel 131-pyridine substituted chlorin e6 derivative (Chlorin A) was synthesized. It has characteristic long wavelength absorption at 664 nm and the emission wavelength at 667 nm. The generation rate of singlet oxygen of this compound is higher than Temoporfin. In vitro, Chlorin A showed higher phototoxicity against the human esophageal cancer cells than Temoporfin while with lower dark-toxicity. Its accumulation effect in mitochondria, lysosomes and endoplasmic reticulum was traced in subcellular localization tests. In flow cytometry obvious apoptosis cells were observed after 2 h irradiation. Significant in vivo photodynamic anti-tumor efficacy was also exhibited on mice bearing esophageal cancer. So Chlorin A could be suggested as a promising anti-tumor drug candidate in photodynamic therapy.