磷酰肌醇-3激酶途径在CML细胞增殖和抗凋亡中的作用

The Effect of phosphatidylinositol-3 kinase on the proliferation and apoptosis blockage in CML cells

为探讨磷酰肌醇-3激酶(PI3K)通路在CML细胞增殖和抗凋亡中的作用,作者应用沃氏篮酶素(Wortmannin,WT)特异性地抑制PI3K激酶活性,经细胞生长曲线测定、半固体集落培养和流式细胞膜联蛋白 V(Annexin V)标记技术,观察了K562和NB4细胞增殖能力与凋亡抗性的改变。结果:WT显著抑制K562细胞增殖能力,24,48及72小时增殖抑制率分别为23.13％。45.17％和60.42％,集落形成抑制率为53.91％(均P<0.05),而对NB4细胞的增生无明显影响;WT可促进由Vp16诱导的K562细胞凋亡。凋亡指数提高1.49倍,NB4细胞的凋亡指数无显著改变。上述结果证明了PI3K在CML细胞增殖和抗凋亡中占重要地位。

The BCR/ABL oncogenic tyrosine kinase is responsible for initiating and maintaining the leukemic pheno-type of Ph + cells. It was recently found that phosphatidylinositol-3 kinase(PI3K) is a substrate of BCR/ABL. The present study is to clarify whether PI3K is functionally significant for Ph+ cell proliferation, and if so, whether inhibition of PI3K activity can promote apoptosis in Ph + cells. The report here showed that wortman-nin (WT), a specific inhibitor of the enzymatic activity of PI3K, suppressed the proliferation and colony forming efficiency of K562 cells as assessed by trypan blue excluxion and colony culture assays. The 24 hrs, 48 hrs and 72 hrs growth inhibition rates were 23.14%, 45.17% and 60.42% respectively, and that of colony forming efficiency was 53.91% . WT dramatically promoted apoptosis of K562 cells induced by Vpl6, as evaluated by flow cytometric annexin-V labelling method, the percentage of apoptotic cells increased more than twice, and the apoptotic index-ratio of apoptotic to necrotic cells was 1.49 times higher than single Vpl6 treatment. However, WT had no effect on the proliferation and apoptosis in NB4 cells. The differential sensitivity of BCR/ABL dependent and independent cell lines to WT suggested that PI3K be required for BCR/ABL to elicit tumorigenic growth and to block apoptotic cell death.