Effects Of Melittin On The Growth In SGC-7901 Cells And Studies On Its Partly Mechanisms Of Action

Gastric cancer is one of the most common malignant tumor, the morbidity and mortality of Gastric cancer accounted for the first place in malignant tumors. Now, Search for effective chemicals is an important research topic for Metastatic gastric cancer patients. Bee venom is eliminated from sting of spado, which is applied for treatment of rheumatoid arthritis, cancer, skin diseases and other diseases, but there are complicated, toxic side effects.melittin is the principal toxic component in the venom of the European honey bee Apis mellifera, it is a small linear peptide composed of 26 amino acid residues. SGC-7901 gastric cancer cell lines are established in vitro. By observing the Melittin on cell proliferation, cell cycle, calcium ion and effect of telomerase in SGC-7901, Discuss the mechanism of Melittin, which provide experimental foundation for development of anti-tumor drug. Mainly includes the following:1. Effects of Melittin on the growth in SGC-7901 cells.1.1. Effects of Melittin on the Morphology of SGC-7901 cells.Melittin could significantly inhibit proliferation of SGC-7901 cells at concentration of 1,2,4,μg·ml-1 in vitro. Using the inverted microscope to observe the Morphology of SGC-7901 cells. 1.2. Using SRB to observe the Melittin on the proliferation of SGC-7901 cellsUsing SRB to observe the effect of Melittin on sensitivity and cell growth curves of SGC-7901 cells, with the dose and time increased, cell growth curve is decreased, and with comparing Melittin to positive control 5-fluorouracil, Melittin displays faster and stronger effects.2. Studies on the anti-tumor mechanisms of Melittin2.1. Effects of Melittin on the cell cycle in SGC-7901 cellsThe changes of cell cycle were detected by flow cytometer when SGC-7901 cells were treated by Melittin after 24 h, SGC-7901 cells accumulated in the G2/M phase after treatment with Melittin (4μg·ml-1) for 24 h, the expression of CylinB 1, CDK1 and Cdc25c mRNA were decreased. Also, related related with cell DNA synthesis of proliferating cell nuclear antigen (PCNA) of mRNA expression were inhibited.2.2. Effects of Melittin on the [Ca2+]i of SGC-7901 cellsThe changes of intracellular free calcium ([Ca2+]i) in HUVECs were determined using fluorescent Ca2+-indicator fluo-3/AM with confocal laser scanning microscope. Result indicate, Melittin significantly promote the Ca2+influx in SGC-7901 cells, the Ca2+ influx changes homeostasis of SGC-7901 cells, resulting in intracellular calcium overload, Melittin combined with calcium channel blockers, the inhibition of cell proliferation increased.2.3. Effects of Melittin on the TERT of SGC-7901 cellsTelomerase reverse transcriptase (TERT) as an important catalytic subunit of telomerase is a major regulator of telomerase activity. effect of Melittin on the TERT protein expression in SGC-7901 cells using Western Blotting, result show, TERT protein expression was decreased after treatment with Melittin (4,8μg·ml-1) for 24 h.