Objective To investigate the role of hydroxyapatite nanoparticle (nHAP) in the gene transfection of human colorectal cancer cell line SW480/M5 and the possible mechanisms.Methods The combination and protection of nHAP-Mg2+ to DNA were analyzed by gelose gelatin electrophoresis.Liposome and nHAP modified by magnesium chloride was combined,and the PEGFP-N1 plasmids were transfected into SW480/M5 cells.The gene transfection rate and the mean fluorescence intensity were observed by flow cytometry.The effect of nHAP-Mg2+ on the growth of the cells were studied by MTT.Results At appropriate proportion,nHAP-Mg2+ could combine the plasmids compeletly and protected the DNA.The gene could not be transferred by nHAP-Mg2+ alone.Combining the nanoparticles and liposome,the gene could be transferred very efficiently and the transfection rates were significantly higher than the liposome (P ＜ 0.05).The inhibition of cell growth was increased along with the concentration of nHAP-Mg2+ wether it was used alone or with the combination of liposome (P ＜ 0.05).Conclusions nHAP-Mg2+ has the ability to combining and protecting DNA and can be used to transfer gene as the adjunct carrier of liposome for the gene therapy of tumor cells to elevate the gene tansfection and expression rate and also enhance the anti-tumor effection.

To investigate the effects of genistein (Gen) on the biosynthesis of N-glycolylneuraminic acid (Neu5Gc) in rats, 80 4-week-old male SD rats were randomly equally into the control and genistein groups. The rats of control and genistein groups were fed 5% ethanol and 300 mg/(kg·d) genistein respectively by gavage. The contents of Neu5Gc in hind leg muscle, kidney and liver tissues of rats were measured by using high performance liquid chromatography coupled with fluorescence detector (HPLC/FLD), and the mechanism of inhibition of Neu5Gc synthesis was investigated by using the molecular docking of Gen and sialyltransferase. On the 15th day, the content of Neu5Gc in hind leg muscle and liver tissues decreased 13.77% and 15.45%, respectively, and there was no significant change in the content of Neu5Gc in kidney tissues. On the 30th day, the content of Neu5Gc in liver tissues decreased 13.35%, however, there was no significant change in the content of Neu5Gc in kidney tissues and Neu5Gc was not detected in hind leg muscle. The content of Neu5Gc in hind leg muscle, kidney and liver tissues decreased respectively 32.65%, 32.78%, 16.80% and 12.72%, 11.42%, 12.30% while rats fed on the 45th and the 60th days. Genistein has formed the hydrogen bond with sialyltransferase activity site residues His319, Ser151, Gly293, Thr328 and formed a hydrophobic interactions with the residues His302, His301, Trp300, Ser271, Phe292, Thr328, Ser325 and Ile274. The results of molecular docking indicated that the weak intermolecular interaction was the main cause of genistein inhibiting sialyltransferase activity. The research results provided an experimental basis for the subsequent reduction of Neu5Gc in red meat before slaughter.
Animals ; Gene Expression Regulation, Enzymologic ; drug effects ; Genistein ; pharmacology ; Male ; Molecular Docking Simulation ; Neuraminic Acids ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Transferases ; metabolism