RESUMO
The developmental process of epithelial-mesenchymal transition (EMT) occurs when epithelial cells acquire invasive mesenchymal cell characteristics, and the activation of this process has been indicated to be involved in tumor progression. EMT could be induced by growth factors, cytokines and matrix metalloproteinases (MMPs). sphingosine-1-phosphate (S1P) is a biologically-active lipid that plays an important role in cancer metastasis. S1P also contributes to the activation of EMT. However, the mechanism underlying S1P-induced EMT is unclear. Increased evidence has demonstrated that the cell surface glycocalyx is closed associated with S1P and plays an important role in tumor progression, suggesting that S1P-induced EMT could be Snail-MMP signaling-dependent. Thus, we hypothesize that an S1P-glycocalyx-Snail-MMP signaling axis mediates S1P-induced EMT. This is an essential step towards improved understanding of the underlying mechanism involved in S1P-regulted EMT, and the development of novel diagnostic and anticancer therapeutic strategies.
RESUMO
The interaction of Ru(bipy)2(dppx)2+ (bipy = 2.2'-bipyridine,dppx = 7,8-dimethyldipyrido phenazine) with the calfthymus DNA has been studied with fluorescence and ultraviolet visible absorption spectroscopy. The results of fluorescence quenching and salt effect show that Ru(bipy)2(dppx)2+ intercalate into the double helix of DNA. The ultraviolet visible absorption spectrum of Ru(bipy)2(dppx)2+, calfthymus DNA, and their interaction indicate that Ru(bipy)2(dppx)2+ intercalate into the double helix of DNA via the ligand dppx.