Résumé
Aim To express and purify rhα-Gal A with a 6 X His tag via using a serum-free expression system in high-density suspension culture of Chinese hamster ovary cells ( CHO-S) , and to verify the scavenging effect of rhα-Gal A on globular trisaccharide ceramide (Gb3 or GL3) . Methods The construction of recombinant protein expression vector, pcDNA4-GLA, was achieved by fusing the human α-galactosidase cDNA, gla, with 6 X His tag and artificial DNA synthesis. The expression plasmid was transfected into the suspended CHO-S to express rhα-Gal A and then purified. Following this procedure, we determined rhα-Gal A's expression, the enzymatic activity, and the glycosylation of the recombinant enzyme. Co-incubation with cultured cells was performed to examine whether rhα-Gal A could be taken up into the cells and effectively remove Gb3 substrates. Results rhα-Gal A was successfully expressed and purified after transiently transfecting pcDNA4-GLA into the suspended CHO-S, and the yield was up to (100 ±20. 6) mg • L
Résumé
Aim To investigate the effect of methionine restriction on the proliferation, migration and invasion of human oral squamous carcinoma CAL-27 cells. Methods Cell proliferation and colony formation ability were detected by cell counting and colony forming assay. The changes in cell cycle and apoptosis were detected by propidium iodide (PI) staining flow cytometry and Annexin V/7-amino-actinomycin staining flow cytometry. The migration and invasion ability of CAL-27 was detected by scratch and Transwell assay. The expression levels of apoptosis proteins Bax and Bcl-2, cyclins CDK2 and CDK4 and migration and invasion proteins N-cadherin and E-cadherin were examined by Western blot. Results Methionine restriction significantly inhibited the proliferation and clone formation of oral squamous cancer cell CAL-27 (P < 0. 01), induced cell cycle arrest at G