OBJECTIVE:To investigate the inhibitory effect of astragalus polysaccharide(APS)on the proliferation of human neuroblastoma SH-SY5Y cells. METHODS:After the cells were cultured with 0(blank control),25,50 and 100 mg/ml APS for 6,12 and 24 h,MTT method was used to determine cell viability and calculate inhibition rate. Following cell cultured with 0 (blank control),25,50 and 100 mg/ml APS for 24 h,Hoechst 33258 fluorescent staining was performed,and then cell nucleus morphology was observed under the fluorescence microscope;flow cytometer was used to detect the distribution of cell cycles and apoptosis;western blot was employed to determine the expression of extracellular regulated protein kinases (ERK) 1/2 protein in cells. Enzyme linked immunosorbent assay (ELISA) was conducted to determine the contents of interleukin 2 (IL-2),IL-6 and IL-12 in the cells. RESULTS:Compared to the blank control,those cultured with 100 mg/ml APS for 6 h,50 and 100 mg/ml APS for 12 h and 25,50 and 100 mg/ml APS for 24 h demonstrated higher inhibition rate. After the cells were cultured with 50 and 100 mg/ml APS for 24 h,those in G0/G1 phase increased and those in G2/M and S phases decreased,and the contents of IL-2 and IL-6 increased. After cells were cultured with 25,50 and 100 mg/ml APS for 24 h,the apoptosis rate was higher,densely hyperchromat-ic fragments in cell nuclei and apoptotic bodies appeared,the phosphorylation level of ERK1/2 protein in the cells was lower,and the content of IL-12 was higher. There was statistically significance (P<0.01 or P<0.05). CONCLUSIONS:APS can inhibit the proliferation of SH-SY5Y cells by arresting cell cycle and inducing cell apoptosis through a mechanism which may be correlated to the decrease in the phosphorylation of ERK1/2 and increase in cytokine.

Objective:To investigate the role of Smad7 in the Hepatocellular carcinoma (HCC) migration and proliferation and its clinical significance.Methods:Through transfecting pcDNA3.1 (+)-Smad7 or siRNA Smad7 to overexpress or knockdown the Smad7 expression in HCC cell lines HepG2 and Huh7.The MTT assays were used to test the role of Smad7 in proliferation of HCC cells.Transwell and wound-healing assays were used to detect the effect of Smad7 on migratory ability in both tow cell lines.RT-PCR was used to test the Smad7 expression in 9 clinical HCC patients' specimens.Results:As the results,overexpression of Smad7 significantly inhibited the proliferation of cells compared with the control group,while knockdown Smad7 promoted the proliferation.At the same time,overexpression of Smad7 could inhibit the migratory ability of HCC cells compared with the control group,while knockdown smad7 could accelerate this ability.The expression of Smad7 in cancer tissue was significantly lower compared with normal mucosa tissue adjacent to cancer.Conclusions:Smad7 is a kind of anti-progressive molecule in HCC.