title: Antitumor function and mechanism of phycoerythrin from Porphyra haitanensis.
abstract: The anti-tumor effect of R-Phycoerythrin (R-PE) from Porphyra haitanensis was studied using cell line HeLa as an in vitro model and Sarcoma-180 (S180) tumor-bearing mice as an in vivo model. The results showed that the combination treatment of R-PE and photodynamic therapy PDT) significantly inhibited the growth of HeLa cells up to 81.5%, with a fair dose-effect relationship, but did not inhibit endothelial cells. The annexin v-fitc/PI fluorescence staining experiments demonstrated that at doses between 0~60µg/mL, apoptosis cells and later stage apoptosis cells or necrosis cells increased significantly as the R-PE dosage increased. DNA electrophoresis showed that after R-PE+PDT treatment of HeLa cells for 24 hours, a light "smear" band between 100~400bp appeared to indicate the degradation of genomic DNA. The QRT-PCR results showed that R-PE+PDT treatment increased caspase-3 and caspase-10 gene expression and decreased the Bcl-2 gene expression level significantly as the R-PE dose increased, implying that R-PE promoted HeLa cell apoptosis. Compared with untreated S180 tumor-bearing mice, R-PE injection significantly inhibited the growth of S180 in tumor-bearing mice up to 41.3% at a dose of 300mg-kg⁻¹. Simultaneously, the significant increase of superoxide dismutase (SOD) activity in serum (p < 0.01) and the decrease of the malondialdehyde (MDA) level in liver suggests that R-PE improved the anti-oxidant ability of the S180 tumor-bearing mice, which may related to its antitumor effect. In addition, the R-PE caused a significant increase (p < 0.05) in the spleen index and thymus index, and a significant increase (p < 0.01) in lymphocyte proliferation, NK cell kill activity and the TNF-α level in the serum of S180 tumor-bearing mice. These results strongly suggest that the antitumor effect of R-PE from Porphyra haitanensis functioned by increasing the immunity and antioxidant ability of S180 tumor-bearing mice, promoting apoptosis by increasing protease gene expression and TNF-α secretion.
authors.affiliation: Department of Biology and Guangdong provincial key laboratory of Marine Biotechnology, Shantou University, Shantou, Guangdong 515063, China.
authors.forename: Qunwen
authors.initials: Q
authors.lastname: Pan
authors.forename: Meizhen
authors.initials: M
authors.lastname: Chen
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Chao
authors.initials: C
authors.lastname: Zhen
authors.forename: Bin
authors.initials: B
authors.lastname: Liang
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage*; D017209:Apoptosis / Q000187:drug effects; D001706:Biopsy; D020169:Caspases / Q000235:genetics; D019254:Genes, bcl-2 / Q000235:genetics; D006367:HeLa Cells / Q000187:drug effects*; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects; D008297:Male; D008315:Malondialdehyde / Q000494:pharmacology; D051379:Mice; D008970:Molecular Weight; D010778:Photochemotherapy; D010799:Phycoerythrin / Q000008:administration & dosage* / Q000302:isolation & purification; D008517:Phytotherapy / Q000379:methods*; D028321:Plant Preparations / Q000008:administration & dosage; D044664:Porphyra / Q000737:chemistry*; D012510:Sarcoma 180 / Q000188:drug therapy* / Q000473:pathology; D013482:Superoxide Dismutase / Q000494:pharmacology
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D028321:Plant Preparations; D010799:Phycoerythrin; D008315:Malondialdehyde; D013482:Superoxide Dismutase; D020169:Caspases