Hispolon (a phenolic compound isolated from Phellinus linteus) has been shown to possess strong antioxidant, anti-inflammatory, anticancer, and antidiabetic properties. In this study, we investigated the antiproliferative effect of hispolon on human hepatocellular carcinoma NB4 cells using the MTT assay, DNA fragmentation, DAPI (4, 6-diamidino-2-phenylindole dihydrochloride) staining, and flow cytometric analysis. Hispolon inhibited the cellular growth of NB4 cells in a dose-dependent manner through the induction of cell cycle arrest at G0/G1 phase measured using flow cytometric analysis and apoptotic cell death, as demonstrated by DNA laddering. Exposure of NB4 cells to hispolon-induced apoptosis-related protein expressions, such as the cleavage form of caspase 3, caspase 8, caspase 9, poly (ADP ribose) polymerase, and the proapoptotic Bax protein. Western blot analysis showed that the protein levels of extrinsic apoptotic proteins (Fas and FasL), intrinsic related proteins (cytochrome c), and the ratio of Bax/Bcl-2 were increased in NB4 cells after hispolon treatment. Hispolon-induced G0/G1-phase arrest was associated with a marked decrease in the protein expression of p53, cyclins D1, and cyclins E, and cyclin-dependent kinases (CDKs) 2, and 4, with concomitant induction of p21waf1/Cip1 and p27Kip1. We conclude that hispolon induces both of extrinsic and intrinsic apoptotic pathways in NB4 human leukemia cells in vitro.

characterized by proteolytic cleavage at a G-protein-coupled receptor proteolysis site (GPS) into an N-terminal fragment (NTF) and a C-terminal fragment (CTF), which remain associated noncovalently. The molecular mechanism and the role of GPS proteolysis in CD97-modulated cell migration are not completely understood. We report here that CD97 expression in HT1080 fibrosarcoma cells enhanced tissue inhibitor of metalloproteinase-2 secretion, leading to reduced membrane type 1 matrix metalloproteinase and matrix metalloproteinase 2 activities. This, in turn, impaired cell migration and invasion in vitro and lung macrometastasis in vivo. CD97 expression also upregulated the expression of integrins, promoting cell adhesion. Importantly, these cellular functions absolutely required the presence of both the NTF and the CTF of CD97, confirming functional cooperation between the two receptor subunits. CD97 gene knockdown reversed these phenotypic changes. We conclude that GPS proteolysis and the functional interplay between the NTF and the CTF are indispensible for CD97 to inhibit HT1080 cell migration by suppressing matrix metalloproteinase activity.

Chitosan and Agaricus blazei Murill (ABM) extracts possess antitumor activities. The aim of the present study was to investigate whether chitosan, ABM extract or the two in combination were effective against tumors in tumor-bearing mice. The mice were subcutaneously injected with SK-Hep 1 cells and were then were divided into the following six groups: Group 1, control group; group 2, chitosan 5 mg/kg/day; group 3, chitosan 20 mg/kg/day; group 4, ABM (246 mg/kg/day) and chitosan (5 mg/kg/day) combined; group 5, ABM (984 mg/kg/day) and chitosan (20 mg/kg/day) combined; and group 6, ABM (984 mg/kg/day). The mice were treated with the different concentrations of chitosan, ABM or combinations of the two for 6 weeks. The levels of glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and vascular endothelial growth factor (VEGF), and tissue histopathological features were examined in the surviving animals. Based on the results of the investigation, the treatments performed in groups 2, 3 and 4 were identified as being capable of reducing the weights of the tumors, however, group 4, which was treated with chitosan (5 mg/kg/day) in combination with ABM (246 mg/kg/day) was able to reduce the levels of GOT and VEGF. As a result, treatment with chitosan in combination with ABM may offer potential in cancer therapy and requires further investigation.