Experimental Study On Anti-Cancer Effects Of Tyroserleutide And Its Mechanisms By Affecting Calcium Homeostasis Of Cancer Cells

Objective: To research the anticancer effect of polypeptides tyroserleutide on human hepatocarcinoma BEL-7402 and to investigate its possible mechanism by affecting calcium homeostasis of tumor cell.Methods: The animal model of human hepatocarcinoma BEL-7402 transplanted in nude is established to observe anticancer effect of tyroserleutide; the electron microscopy is used to investigate effect of tyroserleutide on ultrastructure of human hepatocarcinoma BEL-7402 transplanted in nude mice; applying confocal laser scanning microscope(CLSM) to investigate transient effect of tyroserleutide on calcium homeostasis of BEL-7402 and human normal hepatocyte Chang's Liver cultured in vitro; applying flow cytometry to study them prolonged effect of tyroserleutide on calcium homeostasis ofBEL-7402 and Chang's Liver in vitro; applying flow cytometry to observe effect of tyroserleutide on mitochondria transmembrane potential of BEL-7402 in vitro; measure Ca²⁺-Mg²⁺ ATPase activity of BEL-7402 cells treated by tyroserleutide; applying flow cytometry, electron microscopy and TNUEL technique to observe effect of tyroserleutide on apoptosis and necrosis of BEL-7402 in vitro and in vivo.Results: Tyroserleutide can inhibit growth of human hepatocarcinoma BEL-7402 transplanted in nude mice markedly, the inhibitory rate of tumor growth of 80μg/kg/d, 160μg/kg/d and 320μg/kg/d dosage are 21.66%, 34.78% and 41.34% respectively. Tyroserleutide can also induce tumor cells transplanted in nude mice apoptosis and necrosis, cell organelle mitochondria and endoplasmic reticulum damage, and calcium overload.Observation by CLSM and flow cytometry shows that tyroserleutide can induce concentration of cytoplasmic free calcium in BEL-7402 cell increase markedly in a very short period in vitro. The proportion of calcium increase of BEL-7402 can attain...