Anti-tumor activities of macromolecular fractions of fresh gecko in vivo and their induction of Bel-7402 cell differentiation

Abstract Objective To investigate the anti-tumor effect of macromolecular fractions of fresh gecko (M-AG) in vivo and their differentiation-inducing activity in Bel-7402 cells in vitro . Methods An H22 hepatocarcinoma-bearing mouse model was used to evaluate the anti-tumor activity of M-AG samples. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was applied to analyze cell viability. Cell morphology was observed by phase contrast microscopy. The quantity of the alpha-fetoprotein was detected by a radioimmunoassay. Chromatometry was used to assay the albumin quantity. Activities of alkaline phosphatase and γ-glutamyl trans-peptidase were measured by biochemical methods. Finally, western blotting was applied to assess proteins in the mitogen-activated protein kinase (MAPK) signaling pathway. Results Macromolecular fractions of fresh gecko exerted a significant anti-tumor effect in mice. The inhibition rate of tumor growth was 63% in the moderate M-AG dose group. Cells treated with M-AG displayed a differentiated state. The treatment lowered alpha-fetoprotein secretion and significantly decreased the activities of γ-glutamyl trans-peptidase and alkaline phosphatase in Bel-7402 cells. In contrast, M-AG increased the amount of albumin in the cell culture medium. All biochemical indices demonstrated that M-AG induced Bel-7402 cell differentiation. Western blotting showed no changes in the quantities of extracellular signal-regulated kinase (ERK) 1/2, p38 MAPK, or c-Jun N-terminal protein kinase 1/2. However, M-AG significantly activated the phosphorylation of ERK1/2 in a dose-dependent manner. In addition, M-AG had no significant influence on the expression of nuclear factor-kappa B. Conclusion Macromolecular fractions of fresh gecko has an anti-tumor activity in H22 hepatocarcinoma-bearing mice in vivo and inhibits Bel-7402 cell proliferation in vitro by inducing cell differentiation related to activation of ERK1/2.