慢性粒细胞白血病DNA聚合酶β蛋白研究

Study of DNA polymerase β protein in chronic myeloid leukemia

目的探讨慢性粒细胞白血病（CML）DNA聚合酶β蛋白表达及其与CML急变机制的关系。方法用Western blotting方法检测62例CML患者及K562细胞DNA聚合酶β蛋白表达，并与23例健康人作对照；对26例异基因外周血干细胞移植（allo-PBSCT）及12例使用伊马替尼治疗的CML患者用RT-PCR、Western blotting分别动态检测bcr-abl mRNA和DNA聚合酶β蛋白表达；伊马替尼体外作用于CML患者MNC及K562细胞后，用Western blotting方法检测DNA聚合酶β表达及bcr-abl融合蛋白磷酸化。结果与健康人比较，CML患者及K562细胞DNA聚合酶β蛋白的表达明显升高（P〈0．05）。allo-PBSCT及伊马替尼治疗后患者DNA聚合酶β蛋白的表达随着bcr-abl mRNA表达的降低而下降。伊马替尼体外作用后，DNA聚合酶β蛋白表达随着bcr-abl融合蛋白酪氨酸磷酸化水平的降低而下降。结论bcr-abl融合基因增加DNA聚合酶β蛋白表达；DNA聚合酶β蛋白增加可能是CML急变机制之一。

Objective To investigate expression and regulation mechanism of DNA polymerase β in CML and in blast crisis of CML. Methods Expression of DNA polymerase β was detected by Western blotting in 62 patients with CML and K562 celt line, which were compared with those of normal controls（n =23）. In 26 CML with allogeneic peripheral blood stem cell transplantation （allo-PBSCT） and 12 CML with imatinib treatment, the expression of bcr-abl mRNA and DNA polymerase β protein was detected by semi-quantitative reverse transcription polymerase chain reaction （RT-PCR） and Western blotting, respeetively. After treatment with imatinib to mononuclear cell （MNC） of CML and K562 in vitro, the expression of DNA polymerase β protein and tyrosine phosphorylation of bcr-abl fusion protein was detected by Western blotting. Results The expression of DNA polymerase β protein was significantly enhanced in CML and K562 compared to those of normal controls （P 〈0.05）. In 26 CML with allo-PBSCT and 12 CML patients with imatinib treatment, the expression of DNA polymerase β protein was decreased as the expression of bcr-abl.mRNA decreased. After treatment with imatinib to CML and K562 in vitro, the expression of DNA polymerase β was reduced as tyrosine phosphorylation of bcr-abl fusion protein decreased. Conclusion Bcr-abl fusion gene may enhance expression of DNA polymerase β in CML which may be significantly associated with CML in blast crisis.