Detection of the effect of bortezomib with arsenic trioxide different concentration on the cell cycle and apoptosis of Raji cells by flow cytometry / 白血病·淋巴瘤

Objective To investigate the effect of bortezomib with arsenic trioxide different concentration on the cell cycle and apoptosis of Raji cells. Methods Flow cytometry analysis showed that the relative number of cells in different phases and the percentages of cells calculated in G1 and S phase of the cell cycle and apoptosis were assessed after treatment with As2O3 and BOR or in combination with BOR in different concentration at indicated time (24 h, 48 h, 72 h). Results Flow cytometric analysis showed that the cell cycle was arrested at G1 phase, the number of cells G1 period increased significantly, and S phase decreased on Raji cells after As2O3 treatment. The relationship between the cellular DNA contents and the concentration of As2O3 showed a dose-and time-dependent manner (P ＜0.0001). But it was found that BOR had no effect on Raji cell cycle, but, in two drugs combination, cell apoptosis rate significantly increased from 16.98 % to 45.84 %. Conclusion The results show that As2O3 exerted variable and definite effects on lymphoma Raji cells, which indicated that As2O3 might induce apoptosis and arrest cell cycle. The combination of two drugs had a effective and synergistic effect on apoptosis.

Toosendanin Modifies K~+-and Ca~(2+)-Channel Activity and Intracellular Ca~(2+) Concentration / 生物化学与生物物理进展

Usage of the fruit and bark of a Melia-family plant as a digestive tract-parasiticide and agricultural insecticide was recorded about two thousant years ago in ancient China. Toosendanin (TSN), a triterpenoid, is an effectual ingredient extracted from the plant. Studies have demonstrated that TSN selectively affects neurotransmitter release, effectively antagonizes botulism, induces cell differentiation and apoptosis and inhibits proliferation of various human cancer cells, inhibits feeding and dovelopment in insects and modifies K+- and Ca2+-channel activity. The research data to demonstrate that TSN inhibits K+-channel and facilitates L-type Ca2+-channel are summarized, and the mechanism of action of TSN is discussed.

Studies on The Receptors of Botulinum Neurotoxins / 生物化学与生物物理进展

Botulinum neurotoxin(BoNT) is the most lethal biotoxin known to mankind. It inhibits acetylcholinerelease from the cholinergic nerve ending by cleavage of SNARE proteins, followed by neuromuscular blockadeand paralysis. Gangliosides are considered to act as a first receptor of BoNT with low affinity.Then the membranebound gangliosides-BoNT complex moves laterally to reach and bind the toxin specific protein receptor,synaptotagmin, with a high affinity constant. At last the gangliosides-BoNT-synaptotagmin complex undergoesreceptor-mediated endocytosis. This double-receptors theory is widely accepted. The research data are summarizedand reviewed.