Photodynamic Therapy For Gastric Carcinoma With Photosan-loaded TiO₂Nanoparticles Coated With PEG:an In Vitro And In Vivo Study

PART Ⅰ Killing effects of PDT mediated by Photosan and Photosan-loaded TiO2nanoparticles coated with PEG on AGS human gastric carcinoma cellsObjectiveTo explore the killing effects of Photodynamic Therapy (PDT) mediated by Photosan and Photosan-loaded hollow Titanium dioxide (TiO2) nanoparticles (Nano-Photosan) coated with PEG on AGS human gastric carcinoma cells.MethodsUse MTT assay to measure killing effects of Photosan and Nano-Photosan on AGS human gastric carcinoma cells incubated with varied time and then treated with different concentrations of PSs and light doses.ResultsMTT assay showed no therapeutic effects can be induced by PSs or light alone. Photodynamic inactivation of two PSs were in proportion to concentration, incubation time and light doses; compared with Photosan, nano-Photosan reaches similar cytotoxity effect on AGS human gastric cancer cells in shorter incubation time, with lower concentration and light dose.Conclusion1. No cytotoxic effect could be induced with mere PSs or irradiation in both treating groups2. Nano-Photosan exhibits stronger killing effect on AGS human gastric cancer cells PART Ⅱ Anti-tumor effects of photodynamic therapy mediated by Photosan and nano-Photosan on gastric carcinoma xenografs in nude miceObjectiveTo evaluate the anti-tumor effects on tumor-bearing nude mice models transplanted with AGS human gastric carcinoma cells caused by both Photosan and Nano-Photosan mediated PDT.Methods1. To establish tumor-bearing nude mice models transplanted with AGS human gastric carcinoma cells2. To compare the theraputic effects of PDT mediated by Photosan and Nano-Photosan on tumor-bearing nude mice models transplanted with AGS human gastric carcinoma cellsResults1.80%of all nude mice transplanted with AGS human gastric carcinoma cells were successfully established, The success rate of xenografts model is almost80%.14±3days on average were required for tumors to reached to the volume of about0.2cm.2.2days after PDT treatment, the tumor volume in both treatment groups were smaller than the control group, there was significant difference (P<0.05), and starting from the first8days after PDT, the volumes of relapse tumors in Nano-Photosan group were less than Photosan group (P<0.05), the difference was statistically significant. Conclusion1. Both PSs mediated PDT have significant therapeutic effects on tumor-bearing nude mice models transplanted with AGS human gastric carcinoma cells, anti-tumor effect caused by Nano-Photosan mediated PDT demonstrates longer period of tumor-free survival and longer median survival time.