title: Melittin induces human gastric cancer cell apoptosis via activation of mitochondrial pathway.
abstract: OBJECTIVE
  To investigate the apoptotic effects of melittin on SGC-7901 cells via activation of the mitochondrial signaling pathway in vitro.
  
  
  METHODS
  SGC-7901 cells were stimulated by melittin, and its effect on proliferation and apoptosis of was investigated by methyl thiazolyl tetrazolium assay, morphologic structure with transmission electron microscopy, annexin-V/propidium iodide double-staining assay, measuring mitochondrial membrane potential (MMP) levels, and analyzing reactive oxygen species (ROS) concentrations were analyzed by flow cytometry. Cytochrome C (Cyt C), apoptosis-inducing factor (AIF), endonuclease G (Endo G), second mitochondria-derived activator of caspases (Smac)/direct IAP binding protein with low isoelectric point (Diablo), and FAS were analyzed by western blot. The expression of caspase-3 and caspase-8 was measured using activity assay kits.
  
  
  RESULTS
  Melittin was incubated at 1.0, 2.0, 4.0, or 6.0 μg/mL for 1, 2, 4, 6, or 8 h and showed a time- and concentration-dependent inhibition of SGC-7901 cell growth. Melittin induced SGC-7901 cell apoptosis, which was confirmed by typical morphological changes. Treatment with 4 μg/mL melittin induced early apoptosis of SGC-7901 cells, and the early apoptosis rates were 39.97% ± 3.19%, 59.27% ± 3.94%, and 71.50% ± 2.87% vs 32.63% ± 2.75% for 1, 2, and 4 h vs 0 h (n = 3, P < 0.05); the ROS levels were 616.53% ± 79.78%, 974.81% ± 102.40%, and 1330.94% ± 93.09% vs 603.74% ± 71.99% (n = 3, P < 0.05); the MMP values were 2.07 ± 0.05, 1.78 ± 0.29, and 1.16 ± 0.25 vs 2.55 ± 0.42 (n = 3, P < 0.05); caspase-3 activity was significantly higher compared to the control (5492.3 ± 321.1, 6562.0 ± 381.3, and 8695.7 ± 449.1 vs 2330.0 ± 121.9), but the caspase activity of the non-tumor cell line L-O2 was not different from that of the control. With the addition of the caspase-3 inhibitor (Ac-DEVD-CHO), caspase-3 activity was significantly decreased compared to the control group (1067.0 ± 132.5 U/g vs 8695.7 ± 449.1 U/g). The expression of the Cyt C, Endo G, and AIF proteins in SGC-7901 cells was significantly higher than those in the control (P < 0.05), while the expression of the Smac/Diablo protein was significantly lower than the control group after melittin exposure (P < 0.01). Ac-DEVD-CHO did not, however, have any effect on the expression of caspase-8 and FAS in the SGC-7901 cells.
  
  
  CONCLUSIONS
  Melittin can induce apoptosis of human gastric cancer (GC) cells through the mitochondria pathways, and it may be a potent agent in the treatment of human GC.
authors.affiliation: Gui-Mei Kong, Wen-Hua Tao, Peng-Hua Fang, Ji-Jun Wang, Ping Bo, Feng Qian, Department of Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Medical School of Yangzhou University, Yangzhou 225001, Jiangsu Province, China.
authors.forename: Gui-Mei
authors.initials: GM
authors.lastname: Kong
authors.affiliation: Gui-Mei Kong, Wen-Hua Tao, Peng-Hua Fang, Ji-Jun Wang, Ping Bo, Feng Qian, Department of Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Medical School of Yangzhou University, Yangzhou 225001, Jiangsu Province, China.
authors.forename: Wen-Hua
authors.initials: WH
authors.lastname: Tao
authors.affiliation: Gui-Mei Kong, Wen-Hua Tao, Peng-Hua Fang, Ji-Jun Wang, Ping Bo, Feng Qian, Department of Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Medical School of Yangzhou University, Yangzhou 225001, Jiangsu Province, China.
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Diao
authors.affiliation: Gui-Mei Kong, Wen-Hua Tao, Peng-Hua Fang, Ji-Jun Wang, Ping Bo, Feng Qian, Department of Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Medical School of Yangzhou University, Yangzhou 225001, Jiangsu Province, China.
authors.forename: Peng-Hua
authors.initials: PH
authors.lastname: Fang
authors.affiliation: Gui-Mei Kong, Wen-Hua Tao, Peng-Hua Fang, Ji-Jun Wang, Ping Bo, Feng Qian, Department of Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Medical School of Yangzhou University, Yangzhou 225001, Jiangsu Province, China.
authors.forename: Ji-Jun
authors.initials: JJ
authors.lastname: Wang
authors.affiliation: Gui-Mei Kong, Wen-Hua Tao, Peng-Hua Fang, Ji-Jun Wang, Ping Bo, Feng Qian, Department of Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Medical School of Yangzhou University, Yangzhou 225001, Jiangsu Province, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Bo
authors.affiliation: Gui-Mei Kong, Wen-Hua Tao, Peng-Hua Fang, Ji-Jun Wang, Ping Bo, Feng Qian, Department of Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Medical School of Yangzhou University, Yangzhou 225001, Jiangsu Province, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Qian
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008555:Melitten / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D051336:Mitochondrial Membranes / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000648:ultrastructure; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D017382:Reactive Oxygen Species; D008555:Melitten
keywords: Apoptosis; Cytochrome C; Gastric cancer; Melittin; Mitochondrial