Molecular Analysis of Acute Myelogenous Leukemia Cells Using G-CSF

G-CSF是一种生理性糖蛋白，能够特异性地刺激干细胞向中性粒细胞的增殖和分化，并激活天然中性粒细胞的功能。因此，研究G-CSF是否以及如何作用于以成熟阻滞为特征的急性髓性白血病细胞具有重要意义。大多数急性髓系白血病细胞在G-CSF的特异性结合下表现为增殖但不分化。在一些典型的髓系白血病细胞中，G-CSF可诱导GTP结合蛋白/腺苷酸环化酶系统激活，细胞内Ca ~（2+）增加，蛋白激酶C移位，ALP和hck mRNA表达增加，MPO和myc mRNA表达减少。然而，我们不能显示正常细胞和白血病细胞之间的这些参数的任何明显差异。为了进一步研究，我们试图表征髓系白血病细胞的G-CSF受体（G-CSFR）以及G-CSF应答基因。至于G-CSFR，Nagata博士的小组（大坂生物科学研究所）已经成功地纯化了G-CSFR并克隆了其cDNA。然后，我们与他的小组合作研究了G-CSFR mRNA在各种人白血病细胞中的表达。迄今为止的结果与我们从结合研究中获得的结果一致。根据这些数据，我们正在分析白血病细胞的DNA水平是否存在异常。至于G-CSF应答基因，另一方面，我们最近成功地构建了cDNA文库，使用白血病细胞用或不用G-CSF刺激。我们希望在这一领域的进一步研究可能是重要的，以确定新的基因负责的成熟阻滞特征的急性髓性白血病细胞。

G-CSF is a physiological glycoprotein capable specifically stimulation of the proliferation and differentiation from stem cells to neutrophils as well as activating the functions of nature meutrophils. Therefore it is of great interest to investigate whether or not and how G-CSF might act on acute myelogenous leukemia cells characteristically associated with maturation block. Most of acute myelogenous leukemia cells were shown to proliferate but not to differentiate following the specifical binding of G-CSF. It was also demonstrated in some typical myelogenous leukemia cells that G-CSF induces the activation of the GTP binding proteins/adenylate cyclase system, the increase of intracellular Ca^<++>, the translocation of protein kinase C, the increased expression of ALP and hck mRNAs, and the decreased expression of MPO and myc mRNAs. However, we could not show any clear differences in these parameters between normal and leukemia cells. For further investigation we attempted to characterize the G-CSF receptors (G-CSFR) as well as the G-CSF responsive genes of the myeloid leukemia cells. As for the G-CSFR, Dr. Nagata's group (Osaka Bioscience Institute) had successfully purified G-CSFR and cloned its cDNA. Then we investigated the expression of G-CSFR mRNA in various human leukemia cells in collaboration with his group. The results to date have been compatible with those which we obtained from the binding study. Based on these data, we are now analyzing whether or not there might be any abnormalities at the DNA levels in the leukemia cells. As for the G-CSF responsive genes, on the other hand, we have recently succeeded in constructing the cDNA library using the leukemia cells stimulated with or without G-CSF. We expect that further studies in this area might be important to identify new genes responsible to the maturation block characteristic of acute myelogenous leukemia cells.