ABSTRACT
Objective To explore the causes of Fra-1 high expression in breast cancer cells and molecular mechanism of Fra-1 high transcription activity .Methods Two human breast cancer cell lines MDA231 and MCF-7 and 1 human umbilical vein endothelial cell ECV304 were selected as the research objects .Real time fluorescent quantitative reverse transcription -polymerase chain re-action and Western blotting were used to detect the Fra-1 mRNA and protein expression ;the Fra-1 dual fluorescence reporter vector was constructed ,and the Fra-1 promotor transcription activity was detected ;the Fra-1 promotor short-cut reporter vector and mutation reporter vector at related loci were constructed ,and the transcription activity of short-cut reporter vector and mutation reporter vector was detected ;the binding situation of specific probe marked by biotin with activator protein-1(AP1) was observed by using the gel migration block test .Results The relative expression of mRNA and protein and promotor whole length reporter vector transcription activity of Fra-1 in human breast cancer cell lines MDA231 and MCF-7 cells were higher than that in human umbilical vein endothelial cell MCV304 ,the difference was statistically significant (P＜0 .05);in constructed series Fra-1 promotor shortcut reporter vectors ,only the activity of pGL3B-256 was obviously decreased ,the difference was statistically significant (P＜0 .05);the activity of AP1 mutation reporter vector pGL3B-M2 and SP1 and AP1 dual mutation reporter vector pGL3B-M3 was significantly lower than that of wild repoter vector pGL 3B-M1 ,the difference was statistically significant (P＜0 .05);the gel migration block test found that the binding of specific probe marked by biotin with AP1 had obvious blocking effect .Conclusion In in vitro cultured breast cancer cell lines MDA231 and MCF-7 ,the trans-acting factor AP1 up-regulates its expression by activating Fra-1 gene promoter .