title: Meso-tetra (carboxyphenyl) porphyrin (TCPP) nanoparticles were internalized by SW480 cells by a clathrin-mediated endocytosis pathway to induce high photocytotoxicity.
abstract: We studied the uptake of meso-tetra (carboxyphenyl) porphyrin (TCPP) nanoparticles by SW480 cells and carried out a systematic investigation of the cellular internalization mechanism of TCPP nanoparticles, also studied the photocytotoxicity of TCPP nanoparticles. At first, meso-tetra (carboxyphenyl) porphyrin (TCPP) nanoparticles were prepared by the method of mixing solvent techniques. SW480 cellular uptakes of photosensitizers (TCPP nanoparticles, TCPP-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles and free TCPP) were analyzed by the method of fluorospectrophotometry. Endocytosis mechanism investigation was carried out by preincubating SW480 cells at 4 degrees C, and preincubating SW480 cells with sucrose, K+-free buffer solution and filipin. Clathrin HC expression after incubating SW480 cells with these three photosensitizers was analyzed by methods of Western blot and RT-PCR. At last, we analyzed the photo-cytotoxicity after incubating SW480 cells with photosensitizers and receiving irradiation. SW480 cells showed rapid uptake (0.0083fmoles TCPP/cell) of TCPP nanoparticles after 1h incubation. We also demonstrated that the uptake of TCPP nanoparticles by SW480 cells was a clathrin-mediated endocytosis pathway. As a result of rapid internalization of TCPP nanoparticles by SW480 cells, this special photosensitizer showed very high photocytotoxic effect on SW480 cells in vitro. The nano-sized photosensitizer with no matrix cover: TCPP nanoparticles, can produce higher photocytotoxicity than other photosensitizers (TCPP-loaded PLGA nanoparticles and free TCPP). The in vivo tumor growth inhibition experiment indicated that TCPP nanoparticles plus PDT treatment induced the most dramatic tumor-inhibiting efficacy in all TCPP treated groups. The results of this study suggest that TCPP nanoparticles represent a potential and powerful photodynamic therapy agent.
authors.affiliation: Department of Biomedical Engineering, Xiangya School of medicine, Central South University, Changsha, Hunan 410078, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Hu
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Pan
authors.forename: Jiwei
authors.initials: J
authors.lastname: Wang
authors.forename: Jiji
authors.initials: J
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Lifeng
authors.initials: L
authors.lastname: Ren
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D033922:Clathrin Heavy Chains / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism*; D004705:Endocytosis; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D053758:Nanoparticles; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011166:Porphyrins / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; D033922:Clathrin Heavy Chains; C018395:tetracarboxyphenylporphine; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid