慢性髓系白血病细胞中SphK-1／S1P信号通路的初步研究

慢性髓系白血病（CML）是一种以髓系细胞受累为主的多能造血干细胞的克隆性疾病。为探讨SphK-1／S1P信号通路元件在CML细胞中的表达情况，研究P210^bcr/abl是否涉及到SphK-1／S1P信号通路，首先采用RT—PCR检测bcr／abl阳性的K562细胞和bcr／abl阳性的原代CML细胞中SphK-1和S1P受体mRNA的表达.进一步利用P210^bcr/abl特异抑制剂甲磺酸伊马替尼处理bcr／abl阳性的K562细胞和CML原代细胞，然后通过^32P-ATP掺入法测定细胞内SphK-1的酶活性。结果表明：K562细胞经2．5μmol／L甲磺酸伊马替尼处理0．5,2,6,24和48小时后，对SphK-1活性抑制强度分别为0．007％、38．9％、34．6％、28．1％和76．1％；CML原代细胞在使用2．5μmol／L甲磺酸伊马替尼处理后SphK-1活性较对照下降（16．8—41．9）％。结论：CML细胞中存在SphK-1和S1P的表达，P210^bcr/abl具有激活SphK-1的作用。

SphK-1/S1P Signal Pathway in CML Cells

Chronic myelogenous leukemia (CML) is a clonal myeloproliferative disease of transformed hematopoietic progenitor cells. In order to investigate the role of sphingosine kinase-1 (SphK-1)/sphingosine 1-phosphate (S1P) signal pathway in the expression of CML cells, and to explore whether P210(bcr/abl) involved is activating SphK-1/S1P signal pathwey, the expressions of SphK-1 and S1P receptor mRNA in bcr/abl positive K562 cells and bcr/abl positive primary CML cells were detected by RT-PCR, the imatinib mesylate, the specific inhibitor of P210(bcr/abl) was employed to inhibit the P210(bcr/abl) tyrosine kinases of K562 cells and CML primary cells, and then the intracellular SphK-1 activity was assayed. The results indicated that after being cultured with 2.5 micromol/L imatinib mesylate for 0.5, 2, 6, 24 and 48 hours, the intensions of inhibiting SphK-1 activity were 0.007%, 38.9%, 34.6%, 28.1% and 76.1% resepectively. SphK-1 activity in CML cells also was reduced by 2.5 micromol/L imatinib mesylate (16.8% - 41.9% decrease). It is concluded that the CML cells express SphK-1 and different S1P receptor, and P210(bcr/abl) fusion protein in CML cells can activate SphK-1.