The Mechanism And Killing Effects In Gastrointestinal Stromal Tumor Cells Using Photodynamic Therapy

Objective:1.Explore whether have the specific killing effect of photodynamic technology for GIST-T1.2.Compare the different killing effects between Photosan and nano Photosan mediated photodynamic therapy to gastrointestinal stromal tumor cell.3.Preliminary study nano Photosan and Photosan mediated PDT on cell killing mechanism of gastrointestinal stromal tumor.Methods:1.Using the MTT assay the cytotoxicity of Photosan mediated PDT for gastrointestinal stromal tumor cells (GIST-T1) and fibroblasts (WI-38) and compare the differences.2.Using the MTT detected the cytotoxicity of Photosan and nano Photosan mediated PDT for GIST-T1.3. Using flow cytometry experiments observe cell killing effect of the two photosensitizers mediated PDT for GIST-T1cells, and compare the differences between them, initially identifying the major way of GIST-T1cell death caused by PDT.Results:l.MTT assay showed that under the same conditions (sensitizer concentration, incubation time, light dose) the cell death effect of GIST-T1induced by Photosan-PDT is more obvious than of the WI-38, having specificity (P<0.5). 2.MTT assay showed that Photosan and nano Photosan mediated PDT both have the significant cytotoxicity for GIST-T1cells (P<0.05), while the killing effect of the latter is stronger (P<0.05).3. Killing effect of photodynamic therapy in a range of incubation time, photosensitizer concentration and light dose showed a positive correlation. Two kinds of photosensitizers of best effect parameters is inconsistent.The optimum interaction parameter of nano Photosan required show that the killing effect of it is more stronger than Photosan.4. Flow cytometry experiments show that between Photosan and nano Photosan mediated PDT,the latter of GIST-T1cell killing effect is stronger than the former (P<0.05), and both of them the main pathway of causing GIST-T1cell death is apoptosis. Conclusion:1. In vitro experiments, photodynamic therapy for GIST-T1cells have the specific cytotoxicity.2. Killing effect on GIST-T1cells of PDT showed a positive correlation with photosensitizer incubation time, the concentration of photosensitizer and light dose within a certain range of them.3. Nano Photosan mediated photodynamic therapy have more stronger killing effect to GIST-T1cells with other conditions in the line (photosensitizer incubation time, the concentration of photosensitizer and light dose), and have faster rate to achieve a therapeutically effective concentration, also have lower cytotoxicity and higher security comparing to the Photosan mediated photodynamic therapy.4. In vitro, the mainly pathway of photodynamic therapy to cause GIST-T1cell death is apoptosis.