The interactions between human erythrocyte spectrin(SP) and Pt(II) complexes with different composition and configuration were studied by fluorescence and circular dichroism spectra. The results showed that there are 4.7×10 2 binding sites of cisplatin(CDDP) in a spectrin tetramer(SPT). Among them, about 70 sites with apparent binding constant K 1>3.47×10 6 were of highest affinity, 1.8×10 2 sites with K 2 = 3.47×10 6 were of high affinity, and other 2.2×10 2 sites with K 3 = 8.77×10 5 were of low affinity. The conformation change of spectrin, depending on the concentration of Pt(II) complex and molar ratio(R) of Pt(II) complex to spectrin, was induced by the binding of Pt(II) complexes. It indicated that the interaction of both CDDP and cis diaquodiamine platinum(DADP) with SP followed a two step first order kinetic process in the first stage (1 h), and the kinetic constants were determined. In the second stage, the induced conformation change, polymerization and depolymerization of SP were probably involved. It was noticed that in the reaction of SP and Pt(II) complexes with 1,2 cyclohexanediammine isomers as chiral carrier ligand, stereo matching played a more important role than the affinity of Pt(II) to thiol groups of SP.
In the present study, we investigated the role of reactive oxygen species（ROS） elevation induced by an anti-diabetic vanadium compound, vanadyl acetylacetonate（VO（acac）2）, in the regulation of lipolysis and glucose metabolism using differentiated 3T3L1 adipocytes as a model system. By confocal laser scanning microscopy, we found that VO（acac）2 induced ROS generation under high glucose stimulation, and the pretreatment of NADPH oxidase inhibitors could significantly reduce the elevated ROS level. Meanwhile, the decreased phosphorylated levels of AKT and the two key modulators of lipolysis（HSL and perilipin） were observed by western blot analysis. We also found that the contents of glycerol release were further reduced as well. In addition, the levels of key regulatory proteins, AS160 and GSK3β, in glucose metabolism pathway were correspondingly reduced. These findings demonstrated that ROS induced by vanadium compounds could act as a metabolic signal to activate AKT pathway to inhibit lipolysis and promote glucose transport and glycogen synthesis rather than by direct action by themselves. Our study contributed to elucidate the anti-diabetic effects of vanadium compounds and provided a theoretical basis for the further development of new vanadium complexes in the prevention and therapeutics of diabetes.
In the present study, we investigated the activation of protein kinase C （PKC） family in mouse embryonic fibroblast NIH3T3 cells using gadolinium chloride as a representative lanthanide ion. With live cell imaging system and confocal laser scanning microscopy, we found that the treatment of 50 μM GdCI3 promoted cell survival under the condition of serum-starvation. Moreover, better cell attachment and cytoskeleton reorganization were also observed. Additionally, GdC13 treatment resulted in the phosphorylation of PKC family at different time points. Furthermore, bisindolylmaleimide （a PKCpan inhibitor） could efficiently reduce the level of phosphorylated PKCpan （βIISer660）, alleviating ERK activation induced by GdC13. This finding indicated that the PKC activation was involved in GdC13-induced MAPK/ERK signaling and thus might contribute to GdClβ-indueed cell cycle progression and cell survival.
