ABSTRACT
Objective To observe the effect of bromodomain4 (brd4) inhibitor JQ1 on proliferation inhibition and apoptosis of Ph positive acute lymphocytic leukemia (Ph+ ALL) cells, and to explore the influence on the expression of brd4 and its downstream genes (myc and p53), and the reverse effect on bcr-abl.Methods Different concentrations of JQ1 were used on SUP-B15 cells.The proliferation inhibition rate was detected by MTT, the apoptosis rate was determined by flow cytometry (FCM), and the expressions of bcr-abl mRNA, brd4 mRNA, myc mRNA and p53 mRNA were detected by real-time fluorescent quantitative PCR (RT-PCR).Results Different concentrations of JQ1 inhibited SUP-B15 cells proliferation and induced cell apoptosis.The apoptosis rate was significantly increased compared with that in control group with a time-dose dependent manner.Median inhibitory concentration at 72 h was 1.0 pmol/L.At the same time, JQ1 decreased the transcription levels of bcr-abl mRNA, brd4 mRNA and myc mRNA, and increased the transcription level of p53 mRNA.Conclusions As a brd4 inhibitor, JQ1 can decrease the expression of brd4 to affect the expression of its downstream genes myc and p53, meanwhile, it can change the over expression of bcr-abl to suppress the proliferation of Ph+ ALL cells and induce apoptosis.
ABSTRACT
Objective It has been reported that Ik6 overexpression is associated with poor outcome of childhood pre-B acute lymphoblastic leukemia and Sup-B15 cell line is Ik6 positive.There were fewer studies on the Sup-B15 in the country,so the aim of this research is to explore chemosensitivity and angiogenic potency of pre-B acute lymphoblastic leukemia cell line Sup-B15 associated with Ik6 positive expression through making a comparison between Sup-B15 and Nalm-6 cell line.Methods The Ik6 mRNA and protein expression were detected by nested reverse transcription polymearse chain reaction and Western blot.The effect of vincristine,daunorubicin,L-asparaginase and dexamethasone on the proliferation of cells was measured by using CCK-8 assay.The migration and invasion of cells were detected by transwell assay and mRNA expression of angiogenesis genes (VEGF,Flt-1,PlGF,IGF-1,Ang1 and Ang2) was measured by real-time PCR.Results No expression of Ik6 was detected in Nalm-6 cell line.Compared with Nalm-6,Sup-B15 cell line had a lower rate of growth.The 4 drugs could inhibit the proliferation of cells in a dose-and time-depen-dence manner.Sup-B15 was more sensitive to daunorubicin,L-asparaginase and dexamethasone,and the folds of respective IC50 value were 9.5,1.1 and 1.5.But Sup-B15 was more resistant to vincristine than Nalm-6.The result of transwell assay showed that less Sup-B15 cells transmigrated to the lower chamber.A significant lower expression level of angiogenesis genes was detected in Sup-B15 cells.Conclusion These findings suggest that Sup-B15 is more sensitive to chemotherapy and less angiogenic compared with Nalm-6.