Dürig J, Rosenthal C, Elmaagacli A, Heyworth C, Halfmeyer K, Kasper C, Novotny J, Dührsen U
Department of Haematology, University Hospital Essen, Germany.
Leukemia. 2000 Sep;14(9):1652-60. doi: 10.1038/sj.leu.2401875.
We compared the biological effects of the CXC chemokine SDF-1alpha on immunomagnetically purified CD34+ cells isolated from human normal bone marrow (NBM), leukapheresis products (LP) and patients with chronic myeloid leukaemia (CML). LP CD34+ cells showed a significantly stronger migration response to SDF-1alpha (100 ng/ml) than CD34+ cells isolated from the peripheral blood (PB) of CML patients (P < 0.05). The chemotactic response to SDF-1alpha was also reduced in CML BM CD34+ cells in comparison to NBM CD34+ cells but the observed differences were not statistically significant. In analogy to normal CD34+ cells circulating CML PB CD34+ cells were less responsive to SDF-1alpha than their BM counterparts (P < 0.05). Furthermore, SDF-1alpha elicited similar concentration-dependent growth suppressive effects on normal and CML CD34+ cells (P > 0.05) in colony-forming cell assays. We then demonstrated that SDF-1alpha triggers intracellular calcium increases in CD34+ cells and there were no differences in the time course and dose response characteristics of normal and CML CD34+ cells. The reduced migration response to SDF-1alpha in CML CD34+ cells was not due to a down-regulation of the SDF-1alpha receptor CXCR-4 as flow cytometric analysis revealed similar CXCR-4 expression levels on NBM, LP, CML PB and CML BM CD34+ cells (P > 0.05). Finally, no differences in the modulation of CXCR-4 levels in response to SDF-1alpha and serum were observed in CML and normal CD34+ cells. Our data suggest that the impaired chemotactic response of CML CD34+ cells to SDF-1alpha is not caused by a lack or complete uncoupling of CXCR-4, but may be due to an intracellular signalling defect downstream of the receptor.
我们比较了CXC趋化因子SDF-1α对从人正常骨髓（NBM）、白细胞分离产物（LP）以及慢性髓性白血病（CML）患者中免疫磁珠纯化的CD34+细胞的生物学效应。LP CD34+细胞对SDF-1α（100 ng/ml）的迁移反应显著强于从CML患者外周血（PB）分离的CD34+细胞（P < 0.05）。与NBM CD34+细胞相比，CML骨髓CD34+细胞对SDF-1α的趋化反应也降低，但观察到的差异无统计学意义。与正常CD34+细胞类似，循环中的CML PB CD34+细胞对SDF-1α的反应性低于其骨髓对应细胞（P < 0.05）。此外，在集落形成细胞试验中，SDF-1α对正常和CML CD34+细胞产生了相似的浓度依赖性生长抑制作用（P > 0.05）。然后我们证明SDF-1α可引发CD34+细胞内钙增加，正常和CML CD34+细胞在时间进程和剂量反应特征上无差异。CML CD34+细胞对SDF-1α迁移反应降低并非由于SDF-1α受体CXCR-4下调，因为流式细胞术分析显示NBM、LP、CML PB和CML骨髓CD34+细胞上CXCR-4表达水平相似（P > 0.05）。最后，在CML和正常CD34+细胞中，未观察到对SDF-1α和血清反应时CXCR-4水平调节的差异。我们的数据表明，CML CD34+细胞对SDF-1α趋化反应受损并非由CXCR-4缺乏或完全解偶联引起，而可能是由于受体下游的细胞内信号缺陷。
