Aim The aim of this study is to determine effect of ST2325 on HER2/neu tyrosine kinase signal pathway and cell cycle in breast cancer BT474 cells. Methods Protein expression was detected with immunoblot analysis. Cell cycle distribution was examined using flow cytometry.Results ST2325 inhibited tyrosine phosphorylation of HER-2/neu in a dose-dependent manner with half maximal inhibition occurring at a concentration of 8.7 ?mol?L -1 without reduced HER-2/neu receptor protein expression. Activation of MAPK and AKT, downstream molecules of HER-2/neu-mediated signal transduction pathway was inhibited following exposure to ST2325. After BT474 cells were treated with different concentrations of ST2325 for 24 h, the results of flow cytometry analysis showed cell cycle arrest in G 1 phase. Western blot assay showed up-regulation of p27 protein expression and decrease of hyperphosphorylated Rb and cyclin D1 protein expression.Conclusions ST2325 inhibits HER2 tyrosine kinase phosphorylation and induces G 1 arrest in BT474 cells. Cell cycle arrest in G 1 is associated with p27 up-regulation, decrease of cyclin D1 protein and hyperphosphorylated Rb.

Object To study the inhibitory effect of Anti-EB Virus Liquor (AEVL) on EB (Epstein-Barr) virus antigen expression and its cytotoxicity. Methods The effect of AEVL on Raji cell early antigen (EA) expression and B 95-8 cell virus capsid antigen (VCA) expression was assayed by indirect fluorescent technique; the cytotoxicity on nasopharyngeal carcinoma CNE 2 cells was determined by MTT method. Results At the non-toxic concentration, AEVL had markedly inhibitory effect on Raji cell EB-virus, IC 50 was 0.667 mg/mL and showed powerfully inhibitory effect on B 95-8 cell EB-virus VCA expression, IC 50 was 0.89 mg/mL; and it had strongly inhibitory effect on B 95-8 cell EB virus VCA expression stimulated by sodium n-butyric acid, IC 50 was 1.4 mg/mL. The IC 50 of AEVL on human nasopharyngeal carcinoma CNE 2 cell was 7.57 mg/mL. Conclusion AEVL could inhibit EB virus antigen expression and have cytotoxicity on nasopharyngel carcinoma cells at high concentration.

Aim To investigate apoptosis induced by 3,3'-diethyl-9-methylthia-carbocyanine iodide(DMTCCI) , an inhibitor of DNA primase found in our previous study, and the mechanism of DMTCCI in human myelogenous leukemia HL-60 cells. Methods HL-60 cells were cultured in RPMI-1640 medium and treated with different concentrations of DMTCCI. MTT assay was used to detect growth inhibition.Flow cytometry and DNA ladders were used to detect apoptosis. Western blotting was used to observe the expression of survivin, Bcl-xL, Bad, Bax, Bcl-2, caspase-9, caspase-3, caspase-6, PARP, DFF45 and lamin B protein. Caspase-3 activity was measured by ApoAlert Caspase-3 Assay Kit. Results DMTCCI inhibited proliferation of human leukemia HL-60 cells with IC50 value of 0. 24 μmol · L-1. The results of flow cytometry and DNA ladders showed that DMTCCI could induce apoptosis of HL-60 cells. The expression levels of protein survivin and Bcl-xL were down-regulated, Bad and Bax were up-regulated,while Bcl-2 protein had no change in response to DMTCCI treatment in HL-60 cells. Treatment of HL-60cells with DMTCCI induced the proteolytic cleavage of caspase-9, caspase-3, caspase-6, PARP, DFF45and lamin B protein. Caspase-3 activity apparently increased at 3 h and reached a peak at 12 h after exposure to 1 μmol · L-1 of DMTCCI in HL-60 cells. Conclusion DMTCCI inhibited proliferation and induced apoptosis of human leukemia HL-60 cells. Bcl-2 family proteins, survivin and caspases family proteins might playa role in the apoptosis process induced by DMTCCI.