Synthesis, Characterization And Pro-apoptotic Activity Of Organoantimony And Organobismuth Compounds

Objective:To design and synthesize heterocyclic hypervalent organobismuth and organoantimony compounds and to explore the antitumor function of the cyclic organic antimony and bismuth mechanism.Methods:(1) Ligand precursors including O and N ligating atom have been designed and synthesized, then several heterocyclic hypervalent organobismuth and organoantimony compounds have been synthesized, and characterized by techniques such as nuclear magnetic resonance (NMR), melting point determination, element analysis and X-ray single crystal diffraction analysis technology.(2) It is UV-analysis result that shows interaction between organobismuth (organoantimony) compounds and calf thymus DNA (CT-DNA).(3) Using A549cells, HepG2cells, and Ec109of esophageal carcinoma cells as the model, the complexes with highly anticancer activity can be screened through CCK-8method.(4) Laser confocal microscope is employed to observe the morphology and apoptosis of A549cells.(5) The flow cytometry is adopted to detect the effect of these compounds on cell cycle and cell apoptosis.(6) Realtime PCR and Western blot method is adopted to analyze apoptosis-related genes and proteins levels.Results:(1) Several heterocyclic hypervalent organobismuth and organoantimony compounds have been synthesized, and characterized by techniques such as nuclear magnetic resonance (NMR), melting point determination, element analysis and X-ray single crystal diffraction analysis technology.(2) Organobismuth (organoantimony) compounds interact with calf thymus DNA (CT-DNA) through inserting way. (3) It is found that [t-BuN(CH2C6H4)2BiCl (2a),[O(CH2C6H4)2] BiCl (2d),[O(CH2C6H4)2]BiNO3(2e),[t-BuN(CH2C6H4)2]SbCl (3a) and [{t-BuN(CH2C6H4)2}Sb]2O (3d) that can effectively inhibit tumor cell growth using the CCK-8method.(4) Morphological changes and apoptosis phenomena of A549cells were observed under Laser confocal microscope.(5) Under the treatment by10μmol/L organobismuth compounds2a,2d, and2e for48h, cell cycle was blocked on S phase, and apoptoic rate reached16.07,38.02, and36.69percent, respectively. Organoantimony compounds arrested cell cycle on G2/M phase, and apoptoic rate reached9.08%and16.17percent.(6) It was found that organobismuth compounds2a,2d and2e may increase Bax/Bcl-2mRNA ratio;2a may decrease Caspase-3、Caspase-8mRNA expression (P<0.01);2d may cause Caspase-8mRNA expression falling (P<0.01). Organoantimony compounds3a and3d may up-regulate the ratio of Bax/Bcl-2mRNA; Caspase-3and Caspase-9mRNA expression fall after the treatment of3a (P<0.01), while3d can increase Caspase-9mRNA expression level (P<0.01). Western blot results indicated organobismuth compounds2d and2e may increase the ratio of Bax/Bcl-2protein and Caspase-3protein levels; organoantimony compounds3a and3d could up-regulate the ration of Bax/Bcl-2protein with no obvious change of Caspase-3.Conclusion:(1) Organobismuth (organoantimony) compounds inertact with calf thymus DNA (CT-DNA) through inserting way.(2) Organobismuth (organoantimony) compounds may inhibit A549growth through cell cycle arrest.(3) Through a series experiments on cellular and molecular levels, it is confirmed that organoantimony(organobismuth) compounds can induce cell apoptosis.