Objective To investigate the effect of periplocin of cortex periplocae (CPP) on Stat3 signaling and its probable molecular mechanism of inducing apoptosis and anti-tumor activity. Methods Cell proliferation was detected by MTT. Cell apoptosis and cell cycle were investigated by flow cytometry. Expression of Stat3 protein in SMMC-7721 cells was analyzed by Western blot. Mcl-1, Survivin and XIAP mRNA expressions were measured by RT-PCR. Results CPP inhibited the proliferation of SMMC-7721 cells significantly, induced their apoptosis and arrested their cell cycle at G2/M phase. Decreased expression of Stat3 protein in the cell nucleus was observed after CPP treatment, but no significant changes were found in cytoplasma. Mcl-1, Survivin and XIAP mRNA expression levels were decreased in a time-dependent manner. Conclusion CPP inhibits cell proliferation and induces apoptosis by inhibiting Stat3 signal transduction in human hepatocellular carcinoma cell line SMMC-7721.

OBJECTIVETo study the mechanism of anti-tumor activity of Acanthopanax gracilistylus extract (Age).

METHODSThe tumor cells proliferation was detected by using (3H)-TdR incorporation method, and the effects of Age on cell cycle of tumor cells, retinoblastoma (Rb) protein and cyclin-dependent kinases (Cdk) were analyzed by flow cytometry and Western blotting assay, respectively.

RESULTSIt was indicated by cytoactivity test in vitro that Age only had effect in inhibiting the proliferation of tumor cells, it couldn't lead to death of cells. Under action of Age, the proliferation of tumor cells was halted at G0/G1 stage of cell cycle, and showed no direct cytotoxic effect by Age. Age could induce lowering of the expression of Rb, Cdk2 and Cdk4, cause halt of tumor cell proliferation.

CONCLUSIONThe tumor inhibitory effect of Age is realized by way of regulating the activity of cell cycle controlling enzymes to suspend the proliferation of tumor cells.

Adenocarcinoma ; pathology ; Antineoplastic Agents, Phytogenic ; pharmacology ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase 2 ; biosynthesis ; Cyclin-Dependent Kinase 4 ; biosynthesis ; Drugs, Chinese Herbal ; pharmacology ; Eleutherococcus ; chemistry ; Humans ; Leukemia, T-Cell ; pathology ; Mouth Neoplasms ; pathology ; Retinoblastoma Protein ; biosynthesis ; Stomach Neoplasms ; pathology ; Tumor Cells, Cultured