慢性粒细胞白血病错配修复基因的研究

Study on mismatch repair genes of chronic myeloid leukemia

目的探讨慢性粒细胞白血病(CML)错配修复(MMR)基因的表达水平及调控机制。方法用半定量RT-PCR方法检测62例CML患者及K562细胞的5个MMR基因(hMSH2、hMSH3、 hMSH6、hMLH1、hPMS2)mRNA的表达;用RT．PCR方法动态检测26例进行异基因外周血造血干细胞移植(allo-PBSCT)及4例使用伊马替尼治疗的CML患者bcr．abl及MMR mRNA的表达水平;用伊马替尼体外作用于CML患者的单个核细胞(MNC)及K562细胞后,用Western blot方法检测BCR-ABL融合蛋白的酪氨酸磷酸化水平,RT-PCR方法检测MMR mRNA表达水平。结果与正常人比较,CML患者及K562细胞的hMSH2、hMSH3、hMLH1 mRNA的表达明显降低(P<0．05);26例行allo-PBSCT及4例使用伊马替尼治疗的CML患者,其hMSH2、hMSH3、hMLH1 mRNA的表达随着bcr-abl mRNA的表达降低而升高;伊马替尼体外作用于CML患者MNC及K562细胞后,其hMSH2、hMSH3、hMLH1 mRNA的表达随着BCR-ABL融合蛋白酪氨酸磷酸化水平的降低而升高。结论CML患者、K562细胞hMSH2、 hMSH3、hMLH1 mRNA比正常人降低,bcr-abl融合基因抑制hMSH2、hMSH3、hMLH1 mRNA的表达。

Objective To investigate the expression and regulation mechanism of mismatch repair （MMR） genes in chronic myeloid leukemia （CML）. Methods Expression of MMR genes hMSH2, hMSH3, hMSH6, hMLH1 and hPMS2 mRNAs in 62 CML patients and K562 cell line were detected by semiquantitative reverse transcription polymerase chain reaction （RT-PCR）. Expression of bcr-abl mRNA and MMR genes mRNA were detected by RT-PCR in 26 CML patients with allogeneic peripheral blood stem cell transplantation （allo-PBSCT） and 4 CML patients on imatinib treatment. Expression of bcr-abl mRNA was detected by RT-PCR and tyrosine phosphorylation of BCR-ABL fusion protein by Western blot. Results Expression of hMSH2, hMSH3 and hMLH1 mRNA was significantly lower in CML and K562 cells than in normal control（P 〈0.05）. In 26 CML with allo-PBSCT and 4 CML patients on imatinib treatment, expressions of hMSH2,hMSH3 and hMLH1 mRNA was enhanced while expression of bcr-abl mRNA decreased. In CML MNC after imatinib treatment and in K562 cells, expression of hMSH2, hMSH3 and hMLH1 mRNA was enhanced while tyrosine phosphorylation of BCR-ABL fusion protein decreased. Conclusion Expressions of hMSH2, hMSH3 and hMLH1 mRNA were down-regulated by bcr-abl fusion gene.