PLKB1is Implicated In The Stemness Maintaining Of Acute Myeloid Leukemia Stem Cells

Objective:Our previous studies found that CD34+CD38-acute myeloid leukemia cellshave increased accumulation of DNA damage and ROS but present a lower level ofsenescence. The purpose in this study is further to investigate the mechanisms ofuncoupling ROS and DNAdamage induced cellular senescence in AML stem cells bydetecting the expression and roles of p-LKB1.Methods: The proteins of SIRT1and p-LKB1of CD34+CD38-KG1a AMLcells wereexamined and compared with CD34+CD38-normal cord blood cells byimmunoblotting. Then the inhibition of p-LKB1was induced by activation of SIRT1with resveratrol, and at the same time its effects on senescence, cell cycle,proliferationand apoptosis of CD34+CD38-KG1a AMLcells were investigated.Results: The CD34+CD38-KG1a AML cells remained expression of p-LKB1oncertain level. After treated with resveratol, a activator of SIRT1, they had an increasedexpression of SIRT1but a decreased expression of p-LKB1.At the same time theypresented an increased size, a character of senescent cell, and an elevated expressionof p21, a molecular marker of senescent cell;the analysis of cell cycle showed thepercentage of G0/G1phase cells decreased from39.64%±6.05%to23.35%±5.85%,and that of S and G2/M cells increased from51.85%±5.74%and8.51%±2.47%to64.80%±5.13%and11.85%±5.17%respectively; the absorbance(spectrophotometer reading) of resveratrol treated group, which was detected by MTTfor cells growth, presented a important decrease compared to control group (0.093±6.74%vs0.520±2.45%);the proportion of early apoptosis cells also increased from 0.6%±3.42%to47.5%±4.71%.Conclusion:p-LKB1is implicated in the stemness maintaining of acute myeloidleukemia stem cells, which more enter cell cycle,and present senescence–like change,apoptosis and growth inhibition after p-LKB1is down-regulated.