RESUMO
Compound [Ag42 S5 (StBu)25 (CF3 COO)4 (CO3 )](CO3 )0.5 â CH2 Cl2 â 4CH3 OHâ 9DMF (1) has been obtained and well defined. It consists of a multi-shell structure involving two Ag centres, one Ag5 S5 pentagram, two Ag5 S5 pentagons and one Ag25 S15 shell. Compound 1 has been characterized by XPS, FT-IR, PXRD, TGA, NMR, MS, UV/Vis spectrum, TEM and cyclic voltammetry. Temperature-sensitive luminescent property of 1 has also been investigated.
RESUMO
Numerous studies have showed that chemokine receptors, such as CXCR4, contribute to the growth and metastasis of a variety of malignant tumors. In this study, we investigated the role of CXCR4 in the production of angiogenic factor, vascular endothelial growth factor (VEGF), in various human glioma cells from astrocytic origin. The expression of CXCR4 mRNA and protein in three glioma cell lines, U87-MG, SHG-44, and CHG-5, was determined by RT-PCR and immunocytochemistry, respectively. The malignancies of three gliomas were evaluated by expression of glial fibrillary acidic protein and vimentin, the differentiation markers of astrocytic cells. The role of functional CXCR4 in tumor cell migration was studied with chemotaxis assay. Ca2+ mobilization and VEGF production were measured in the cells after stimulation with CXCR4 ligand, SDF1beta. The results showed that the levels of functional CXCR4 expression at both mRNA and protein levels by several human glioma cell lines were correlated with the degree of differentiation of the tumor cells. Activation of CXCR4 induced glioma cell chemotaxis and could trigger the increase of intracellular [Ca2+]i. Such an activation could result in the increased production of VEGF by the stimulated tumor cells. Our results suggest that CXCR4 may contribute to the high level of VEGF produced by malignant glioma cells and thus constitute a therapeutic target for antiangiogenesis strategy.