Effects of tachyplesin on proliferation and differentiation of human hepatocellular carcinoma SMMC-7721 cells

AIM:To investigate the antitumor activities of tachyplesinon human hepatocellular carcinoma(HCC)cells.METHODS:Tachyplesin,isolated from acid extracts ofChinese horseshoe crab(Tachypleus tndentatus)hemocytes,was used to treat the human HCC cell line SMMC-7721.Effectsof tachyplesin on the proliferation of SMMC-7721 cells weremeasured with trypan blue dye exclusion test and HE staining.The morphology and ultrastructure of the cells were examinedby light microscopy and transmission electron microscopy,respectively.The activities of γ-glutamyltransferase(γ-GT)andtyrosine aminotransferase(TAT)were assayed withbiochemical methods.The levels of alpha fetoprotein(α-FP),proliferating cell nuclear antigen(PCNA),p21WAF1/CIP1and c-myc were examined by immunocytochemistry.RESULTS:After treatment with tachyplesin 3.0 mg/L,theproliferation of SMMC-7721 cells was inhibited significantly,with the cell growth inhibitory rate amounted to 55.57 % andthe maximum cell mitotic index declined by 43.68 %.Themorphology and ultrastructure underwent restorationalalteration.The activity of γ-GT declined while TAT activityincreased obviously,and the levels of α-FP and PCNA decreased.Moreover,the expression of p21WAF1/CIP1protein was up-regulated and that of c-myc protein was down-regulated.CONCLUSION:Tachyplesin could effectively inhibit theproliferation of hepatocarcinoma cells,reverse the malignantmorphological and ultrastructural characteristics,alter thelevels of enzymes and antigens,regulate the expression ofdifferentiation-associated oncogene and tumor suppressorgene,and induce hepatocarcinama cell differentiation.