EGCG enhances TRAIL-mediated apoptosis in human melanoma A375 cell line.
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anti-cancer agent. Epigallocatechin-3-gallate (EGCG) is a polyphenolic constituent of green tea. In this study, inhibitory effect of combined use of EGCG and TRAIL on human melanoma A375 cells was examined and the possible mechanism investigated. The cells were divided into 4 groups: control group, EGCG group (EGCG: 10, 20 mug/mL), TRAIL group (TRAIL: 25 ng/mL) and EGCG+TRAIL group (combined group). The growth inhibition was measured in the A375 cells treated with different concentrations of TRAIL ((25, 50, 75, 100, 125, 150 ng/mL) by MTT assay. The apoptosis was assessed by flow cytometry. The expressions of DR4 and DR5 were detected by flow cytometry and western blotting. The activities of caspase-8 and caspase-3 were determined by colorimetric assay. The results showed that TRAIL could dose-dependently inhibit the growth of A375 cells and the IC(50) of TRAIL was 150 ng/mL. The apoptosis rate was 11.8% in the TRAIL group, 5%-7% in the EGCG group and 48.9%-59.1% in the combined group. Significant difference was found in the apoptosis rate between the combined group and the EGCG or TRAIL group (P<0.05 for each). The expression of DR4 instead of DR5 was significantly increased in the EGCG group. The activity of caspase-3 rather than caspase-8 was substantially enhanced in the EGCG group. These results suggest that EGCG is useful for the TRAIL-based treatment for melanoma.
Shen
Qin
Q
Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China. shenqin1220@tom.com
Tian
Fen
F
Jiang
Ping
P
Li
Yanqiu
Y
Zhang
Li
L
Lu
Jingjing
J
Li
Jiawen
J
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D004357:Drug Synergism; D006801:Humans; D008545:Melanoma / Q000473:pathology*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism; D012878:Skin Neoplasms / Q000473:pathology; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*
D000970:Antineoplastic Agents; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505653:TNFSF10 protein, human; D002392:Catechin; C045651:epigallocatechin gallate; C505407:CASP3 protein, human; C505530:CASP8 protein, human; D053148:Caspase 3; D053181:Caspase 8