Yoshida T, Ishida Y, Sasaki H, Inoue T, Kaku K, Kaneko T
Third Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan.
Am J Hematol. 1992 Jan;39(1):32-8. doi: 10.1002/ajh.2830390108.
In this study, specific binding sites were examined for erythropoietin (EPO) on the mouse leukemic cell line, L8057. This cell line is megakaryoblastic in origin as evidenced by an enlargement of cell size, multinuclearity, intense activity of acetylcholinesterase, more expression of glycoprotein IIb and IIIa antigen, and higher ploidy distribution after the treatment with 12-o-tetradecanoylphorbor-13-acetate (TPA). The original undifferentiated cells possessed a single class of low affinity binding sites for recombinant human (rh) EPO with a Kd of 3.5 nM. Following the treatment with TPA, high affinity binding sites (Kd; 440 pM) were expressed in addition to the low affinity sites. EPO stimulated the incorporation of 3H-leucine into TPA-treated L8057 cells, and the maximal effect of EPO was observed at the same order as the Kd value of high affinity sites. The present data demonstrates that the expression of high affinity binding sites for EPO is associated with the differentiation of L8057 cells which have megakaryocytic characteristics. Furthermore, protein synthesis stimulated by EPO may be mediated through the high affinity sites.
在本研究中，检测了促红细胞生成素（EPO）在小鼠白血病细胞系L8057上的特异性结合位点。该细胞系起源于巨核母细胞，经12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA）处理后，细胞大小增大、多核、乙酰胆碱酯酶活性增强、糖蛋白IIb和IIIa抗原表达增加以及倍性分布更高，均证明了这一点。原始未分化细胞对重组人（rh）EPO具有一类低亲和力结合位点，解离常数（Kd）为3.5 nM。用TPA处理后，除了低亲和力位点外，还表达了高亲和力结合位点（Kd；440 pM）。EPO刺激3H - 亮氨酸掺入TPA处理的L8057细胞中，并且在与高亲和力位点的Kd值相同的顺序下观察到EPO的最大效应。目前的数据表明，EPO高亲和力结合位点的表达与具有巨核细胞特征的L8057细胞的分化相关。此外，EPO刺激的蛋白质合成可能通过高亲和力位点介导。
