Effect of low dose radiation on expression of p16 gene in chronic myelogenous leukemia cells / 中华放射医学与防护杂志

ABSTRACT

Objective To investigate the effect of low dose radiation on the expression of p16 gene in chronic myelogenous leukemia.Methods Leukemic stem cells(LSCs)which expressed CD34+,CD38- and CD123+ were isolated from bone marrow cells obtained from twenty patients newly-diagnosedas chronic myeloid leukemia with EasySepTM magnet beads.Hematopoietie stem cells(HSCs) which expressed CD34+ and CD38- were isolated from human cord blood cells obtained from twenty full-term deliveries with EasySepTM magnet beads as control.HSCs vs LSCs samples were further divided into three dose groups,including 0,12.5 and 50 cGy,respectively.RT-PCR and real-time quantitative reverse transcription-polymerase chain reaction methods were used to detect mRNA expression of p16 gene in HSCs and LSCs after irradiation.Cells were harvested at different time for detection of cell cycle and apoptosis by flow cytometer.Results p16 mRNA level in CML-LSCs was increased slightly at 12.5 cGy,and significantly increased at 50 cGy(Z=-3.39,P<0.01),but ho significant change was found in HSCs.The percentage of CML-LSCs cell in G0/G1 stagewas increased 48 h after 12.5 cGy irradiation,and 72 h post-irradiation with 50 cGy.The apoptosis rate of CML-LSCs was gradually raised after LDR,especially at 72 h post-irradiation of 50 cGy[(17.75±11.76)%vs(6.13±4.71)%,Z=-2.37,P<0.01 ].Conclusions p16 gene transcription could be up-regulated by low dose radiation,which might provide a theoretical evidence for CML therapy and LDR in leukemic clinical application.