Role of transferrin, Fe, and transferrin receptors in myeloid leukemia cell growth. Studies with an antitransferrin receptor monoclonal antibody.
Role of transferrin, Fe, and transferrin receptors in myeloid leukemia cell growth. Studies with an antitransferrin receptor monoclonal antibody.
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DOI：
10.1172/jci111768
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发表时间：
1985-03
期刊：
影响因子：
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通讯作者：
R. Taetle;K. Rhyner;J. Castagnola;D. To;J. Mendelsohn
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文献类型：
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作者：
R. Taetle;K. Rhyner;J. Castagnola;D. To;J. Mendelsohn
在以往的研究中，抗转铁蛋白受体抗体42/6抑制正常粒细胞/巨噬细胞祖细胞和部分恶性骨髓细胞的生长。本研究利用无血清培养的白血病细胞系和新鲜白血病细胞，研究铁、转铁蛋白受体和转铁蛋白在白血病细胞生长中的作用，以及42/6抑制和耐药的机制。在无血清培养基中生长的HL60和KG-1白血病细胞受到42/6的抑制。与胎牛血清（FCS）的结果相反，可溶性铁（硝酸乙酸铁）逆转了无血清HL60细胞42/6的生长抑制。当HL60细胞适应于无血清、无转铁蛋白的培养基中生长时，它们对42/6的生长抑制变得不耐。通过使用放射性标记的转铁蛋白和42/6，FCS和转铁蛋白培养的HL60细胞显示出相似数量的转铁蛋白受体（29,000-30,000/细胞）和相似的Kd （3.8-4.9 X 10(-9) M）。在无转铁蛋白培养基中生长的细胞显示相似的Kd (3.1 X 10(-9) M)，但转铁蛋白结合位点较少（5000个/细胞）。不依赖转铁蛋白的细胞含有高浓度的胞内铁蛋白。对于FCS和无血清的HL60细胞，42/6的计算亲和力较低（5.7-10.0 X 10(-9) M），但结合位点的数量高出3 - 4倍。为了进一步研究正常和恶性骨髓细胞增殖中受体显示与抗体抑制之间的关系，我们采用同步免疫荧光法测定转铁蛋白受体阳性细胞的细胞周期状态。恶性细胞在S + G2/M中显示的转铁蛋白受体约为正常分裂集落刺激因子刺激的骨髓细胞的50%。两例急性非淋巴细胞白血病患者的细胞分裂显示受体是不同的。当二甲亚砜处理HL60细胞时，转铁蛋白受体显示减少，42/6生长抑制消失或明显减弱。在含血清或无血清培养中，42/6的存在并不能阻止二甲亚砜诱导的HL60分化。我们得出结论，人类白血病细胞生长需要铁，42/6通过缺铁抑制转铁蛋白依赖性细胞。一些正在分裂的正常细胞和正在分化的恶性细胞显示转铁蛋白受体减少，也可以逃避抗体抑制。在不依赖转铁蛋白的HL60细胞中，铁蛋白水平升高，转铁蛋白受体减少，证实了细胞铁蛋白含量与转铁蛋白受体显示呈反比关系。这些研究表明铁在白血病细胞生长和细胞分化中可能起关键作用。
In previous studies, antitransferrin receptor antibody 42/6 inhibited growth of normal granulocyte/macrophage progenitors and some malignant myeloid cells. In these studies, leukemia cell lines cultured without serum and fresh leukemia cells were used to investigate the roles of Fe, transferrin receptors, and transferrin in leukemia cell growth, and mechanisms of 42/6 inhibition and resistance. HL60 and KG-1 leukemia cells grown in serum-free medium were inhibited by 42/6. In contrast to results in fetal calf serum (FCS), soluble Fe (ferric nitriloacetate) reversed 42/6 growth inhibition of serum-free HL60 cells. When HL60 cells were adapted for growth in serum-free, transferrin-free medium, they became refractory to 42/6 growth inhibition. By using radiolabeled transferrin and 42/6, HL60 cells cultured in FCS and transferrin displayed similar quantities of transferrin receptors (29,000-30,000/cell) and similar Kd's (3.8-4.9 X 10(-9) M). Cells grown in transferrin-free medium showed a similar Kd (3.1 X 10(-9) M), but fewer transferrin binding sites (5,000/cell). Transferrin-independent cells contained a log higher concentration of intracellular ferritin. For both FCS and serum-free HL60 cells, calculated affinities for 42/6 were lower (5.7-10.0 X 10(-9) M), but the number of binding sites was three- to fourfold higher. To investigate further the relationship between receptor display and antibody inhibition in proliferating normal and malignant myeloid cells, simultaneous immunofluorescence was used to determine the cell cycle status of transferrin receptor-positive cells. Malignant cells in S + G2/M displayed approximately 50% of the amount of transferrin receptors detected in normal dividing colony-stimulating factor-stimulated marrow cells. Receptor display by dividing cells from two patients with acute nonlymphocytic leukemia was variable. When HL60 cells were exposed to dimethyl sulfoxide, transferrin receptor display decreased, and 42/6 growth inhibition was abrogated or greatly diminished. The presence of 42/6 did not prevent dimethyl sulfoxide-induced HL60 differentiation in serum-containing or serum-free cultures. We conclude that human leukemia cells require Fe for growth and that 42/6 inhibits transferrin-dependent cells by Fe deprivation. Some dividing normal and differentiating malignant cells display reduced transferrin receptors, and can also escape antibody inhibition. The increased ferritin levels and decreased transferrin receptors in transferrin-independent HL60 cells confirm the inverse relationship between cell ferritin content and transferrin receptor display. These studies indicate a critical role for Fe in leukemia cell growth and possible roles in cellular differentiation.