Methods: G-chlorin e6 was synthesized with a core photosensitizer chlorin e6 conjugated to glucose. 1); The half maximal inhibitory concentration (IC50) was measured to compare the PDT effects of G-chlorin e6 and TS. 2); Flow cytometry was performed to examine the accumulation of G-chlorin e6 in cancer cells. We also compared the accumulation of G-chlorin e6 between normal immortalized esophageal epithelial cells and esophageal cancer cells. 3); In vivo using mice evaluation, the radio activated carbon 14 labeled G-chlorin e6 was manufactured for evaluation of the excretion from the body. 4); Antitumor effects of G-chlorin e6 PDT were analyzed in allograft tumor mouse models.
Results: 1); PDT in vitro using G-chlorin e6 elicited 9, 000-34,000 times stronger antitumor effects than TS. 2); there was 70-190 times more G-chlorin e6 accumulated than TS by flow cytometry. G-chlorin e6 accumulated more selectively in esophageal cancer cells than in esophageal immortalized epithelial cells. 3); The excretion of G-chlorin e6 from plasma to bile juice was much faster than that of TS. 4); In an allograft model, PDT with G-chlorin e6 showed very strong antitumor effects and a 40% complete response (CR) rate.