Selenium dioxide induces leukemia cell apoptosis and changes of intracellular reactive oxygen species (ROS) and Ca~(2+) levels / 中国病理生理杂志

AIM: The effects of selenium dioxide (SeO_2) on proliferation, apoptosis, intracellular reactive oxygen species (ROS) and Ca~(2+) levels in three leukemia cell lines NB4, K562 and HL-60 were investigated. METHODS: Three leukemia cell lines were treated with 3-30 ?mol/L SeO_2. Flow cytometry was used to detect apoptosis rate, and analyze the changes of ROS and Ca~(2+) level within cells. RESULTS: SeO_2 at 10 and 30 ?mol/L inhibited proliferation in three leukemia cell lines. Treatment with 30 ?mol/L SeO_2 for 48 h induced 54.0%, 46.5%, 49.6% apoptosis in NB4, K562, and HL-60 cells, respectively, and also markedly decreased ROS and Ca~(2+) levels among three cell lines. The rate of ROS positive cells in NB4 and HL-60 decreased with the increase in SeO_2 concentrations. ROS was clearly reduced with 30 ?mol/L SeO_2 in K562. Ca~(2+) levels were tardily declined with 10, 30 ?mol/L SeO_2 in NB4 and HL-60 cells. Ca~(2+) levels were clearly reduced with 30 ?mol/L SeO_2 in K562. CONCLUSION: SeO_2 induces apoptosis in three leukemia cells. The declines of intracellular ROS and Ca~(2+) levels are involved in apoptosis induced by SeO_2.

INHIBITION OF TETRANDRINE AND DEMETHYL TETRANDRINE ON DNA, RNA AND PROTEIN SYNTHESES OF LEUKEMIA 7712 AND SARCOMA 180 CELLS / 中国药理学通报

The 50% inhibition doses ( ID50 ) of tetrandrine and demethyl tetrandrine on DNA synthesis in L7712 and Sl80 cells are 2.6, 3 .5mg/ L and 27.5, 24.5mg/L respectively. The DNA synthesis inhibition is likely due to DNA template damage caused by both natural products. The inhibition of DNA, RNA and protein syntheses by tetrandrine or demethyl tetrandrine increased with incubating time. The inhibiting activities of two natural products on DNA and RNA synthesis are s-tronger than on protein. There are no differences either in inhibiting activity or in inhibiting mechanism between two natural products.

The antitumor activity of clostridium difficile toxin A / 中国药理学通报

AIM To examine the antitumor activity of clostridium difficile toxin A. METHODS Highly purified toxin A from clostridium difficile was obtained by bovine thyroglobulin affinity chromatography followed by ion exchange chromatography steps on Q sepharose. The antitumor activity of toxin A of clostridium difficile on TPC 1 cell line was studied with Vero cell line as the normal cell line. The estimating ways used in this study were trypan blue exclusion test, MTT calorimetric assay, membrane damage test using 3H Uridine and observation by optical, fluorescence microscopes. RESULTS Exposed to toxin A, the cell growth inhibition, apoptosis index, non adherent cells and membrane damage in TPC 1 cell line were much more great than that in vero cell line, and the effect was dependent upon the concentration and treating time. CONCLUSION The antitumor activity of toxin A on TPC 1 cells was much higher than that on vero cell line. The data are of potential importance for the development of toxin A and the exploration of antitumor drugs.