Effects Of Sp100 And LG268 On Acute Promyelocytic Leukemia Cell Line NB4 Cells And Its Mechanism

PART ?Expression of Sp100 induced by ATRA and its effect onproliferation in NB4 cellsObjective:To investigate the expression of Sp100 in ATRA-treated NB4 cells and its effect on proliferation in NB4 cells.Methods : NB4 cells were treated with 1 ?M ATRA,and then quantitative PCR(q-PCR)was employed to measure the expression of Sp100 m RNA;Western blot was used to detect the expression of Sp100 protein;Indirect immunofluorescence was adopted to determine the location of Sp100.The lentivirus harboring RNA interference sequence targeting the Sp100 was used to infect NB4 cells,and western blot was use to verify the expression of Sp100 protein;Cell viability was analyzed by CCK8 and Flow cytometry was used for cell cycle analysis.Results: ATRA could induce obviously the expression of m RNA and protein of Sp100 in NB4 cells;ATRA changed the location of Sp100 from a micro-punctate pattern into a punctate nuclear pattern.NB4 cells with stable knockdown of Sp100 protein were constructed,and Sp100-sh RNA promoted the proliferation of NB4 cells and increased the cells in G2/M phase.Conclusions: The expression of Sp100 was significantly increased in ATRA-treated NB4 cells,and Sp100 may be involved in the regulation of proliferation activity of NB4 cells.PART ?Effects of LG268 on Cell Proliferation andApoptosis of NB4 CellsAims: To investigate the effects of LG100268(LG268)on cell proliferation and apoptosis in NB4 cells.Methods: NB4 cells were treated with LG268 for 24 h or 48 h,and the effect of LG268 on cell proliferation was assessed by the CCK-8 assay and colony-forming assay.Apoptosis and cell cycle were evaluated by FCM.The protein expression levels of Survivin,PARP,c-Myc,cyclin D1,ERK,p-ERK,p38 MAPK,and p-p38 MAPK were detected by western blot.Results: We found that LG268 inhibited the proliferation of NB4 cells in a dose-dependent manner.FCM showed that LG268 accelerated apoptosis in NB4 cells in a time-dependent manner and that LG268 treatment led to cell cycle arrest at G0/G1 phase.Moreover,LG268 significantly decreased the protein levels of Survivin,c-Myc,and cyclin D1.Cleaved PARP was observed only in the LG268 treatment group but not in the control group.In addition,LG268 increased the phosphorylation level of p38 MAPK and decreased the phosphorylation level of ERK.Conclusions: LG268 inhibited cell proliferation and promoted cell apoptosis in NB4 cells.