Expression Of Homeobox A7in Acute Promyelocytic Leukemia(NB4) Cell And Effect Of ATRA On Its Expression

bjective: This research was aimed at investigate theespression of the homeobox A7(HOXA7) in human Acute PromyelocyticLeukemia (NB4)Cell and what effect the all-trends retinoic acid (ATRA)have on its expression to explore the pathogenesis of leukemia mediated byHOXA7. Methods:1. Culture NB4cell cline in vitro as a model of themyeloid leukemia cell.2. CCK-8method was adopted to detect both thefinal concentration of drug and the point-in-time of Intervention to NB4cellproliferation.3.Group (divide the experiments into four groups):Everygroup contains106/ml logarithmic cells.And optimal concentration ofATRA was injected into the other three experimental group at4h,48h,96hrespectivey,also the control group insteaded of same1640culture medium.4. Investgate the growth of NB4cell line in every group with the interfere ofthe ATRA.5. Use Wright staining to identify the NB4cells and to observethe morphological change of nucleus and cytoplasm and the growthdifferentiation in different NB4cell induced by ATRA.6.The distributionlevel of HOXA7protein in NB4cells were detected by Real-timefluorescent quantitative-PCR (FQ-RT-PCR)， Western blot(WB) andimmunohistochemical technique(IHC).7.All the data was processed byhomogeneity test of variance by using the statistical software SPSSl7.OAONVA，between group mean pairwise comparisons with LSD method. If P<0.05,it was considered statistically signification. Results:1. The CCK-8method confirmed that the optimal concentration of ATRA were1.0μmol/l,lower concentration almost have no affect and higherconcentration have toxicity to it. After intervention, the proliferation ofNB4cell was inhibited, and it is obvious after48hours, also the inhibitingbecomes stronger with the time goes by.So at4h,48h,96h respectively afterthe ARTA had been injected was the most appropriate time.2.Morphological identification of NB4cell line:In wright staining,the cell isacute promyelocytic leukemia cell.after being induced by ATRA, observedby an invert optical microscope,the leukocytes showed that nucleusbecomes smaller and with lobes,folding,fossa also inclined to oneside.Besides,the leukocytes demonstrared more for increasing cytoplasmand decreasing or disappearing nucleolus. And it is obvious after48h.3.Invitro culture system of NB4cells,with a final concentration of1μmol/lATRA continued interventing the cell can promote the differentiation of tnecells in every experimental group.4.The high expression ofHOXA7showed a downward trend in the NB4cells after injecting withATRA at4h,48h and96h respectively.And the expression quantity ofHOXA7mRNA and protein at48h and96h was significantly lower than thecontrol group (P<0.05). Conclusion:The experiment proved that theHOXA7protein and gene express on the acute myeloid leukemia NB4cellline. And1.0μmol/l ATRA could induce the NB4cells to differentiate into the mature cell through decreasing the expression of HOXA7mRNA andprotein. The research also suggested that HOXA7might be a new gene thatinfluences the maturation of acute myeloid leukemia and the treatmentmechanism for leukemia may have something to do with the expression ofHOXA7mRNA and protein regulated by ATRA..