Brodie C, Siriwardana G, Lucas J, Schleicher R, Terada N, Szepesi A, Gelfand E, Seligman P
Department of Medicine, University of Colorado Health Sciences Center, Denver 80262.
Cancer Res. 1993 Sep 1;53(17):3968-75.
Iron (Fe) is known to be necessary for cellular proliferation. Previous studies have suggested that neuroblastoma cells appear to be relatively sensitive to growth inhibition by a specific Fe chelator, deferrioxamine (DFO), in vitro. Also, DFO has been recently used for the treatment of neuroblastoma patients. In this paper we demonstrate that neuroblastoma cell proliferation in vitro is extremely sensitive to inhibition by DFO as compared to another cell line with almost identical growth kinetics. Neuroblastoma cells treated with DFO adapt appropriately to Fe chelation as measured by marked upregulation of transferrin receptor mRNA, increased functional transferrin receptor, and decreased cellular ferritin concentration. Further studies that quantitated cellular incorporation of 59Fe from added transferrin-59Fe in the presence of DFO indicated that neuroblastoma cells were more sensitive to inhibition of Fe incorporation by the chelator as compared to the other cell line. Neuroblastoma cells treated with DFO showed a consistent arrest in the G1 phase of the cell cycle. For cells taken from the "resting" state this block occurred before the vast majority of cells had entered S or G2-M phases of the cell cycle. Further evidence that neuroblastoma cells were arrested before the G1-S interface was provided when cells inhibited by DFO and released into aphidicolin exhibit arrest at the G1-S interface, whereas release from aphidicolin into DFO resulted in entry into S phase. Also, DFO-treated cells exhibited a decrease in both p34cdc2 immunoreactive protein as well as kinase activity. The results of these latter studies strongly indicate evidence for a Fe requirement for malignant cell proliferation before the onset of DNA synthesis. Our results also provide a basis for further studies that will better define a therapeutic approach to patients with neuroblastoma utilizing DFO treatment.
已知铁（Fe）对于细胞增殖是必需的。先前的研究表明，神经母细胞瘤细胞在体外似乎对特定的铁螯合剂去铁胺（DFO）的生长抑制相对敏感。此外，DFO最近已被用于治疗神经母细胞瘤患者。在本文中，我们证明，与另一种具有几乎相同生长动力学的细胞系相比，神经母细胞瘤细胞在体外增殖对DFO的抑制极其敏感。用DFO处理的神经母细胞瘤细胞通过转铁蛋白受体mRNA的显著上调、功能性转铁蛋白受体的增加和细胞铁蛋白浓度的降低来适当地适应铁螯合。进一步的研究对在DFO存在下从添加的转铁蛋白 - 59Fe中细胞摄取59Fe进行了定量，结果表明与另一种细胞系相比，神经母细胞瘤细胞对螯合剂抑制铁摄取更敏感。用DFO处理的神经母细胞瘤细胞在细胞周期的G1期出现持续停滞。对于从“静止”状态获取的细胞，这种阻滞发生在绝大多数细胞进入细胞周期的S期或G2 - M期之前。当被DFO抑制并释放到阿非科林中的细胞在G1 - S界面处停滞，而从阿非科林释放到DFO中导致进入S期时，进一步证明了神经母细胞瘤细胞在G1 - S界面之前被阻滞。此外，DFO处理的细胞在p34cdc2免疫反应性蛋白以及激酶活性方面均表现出下降。这些后续研究的结果有力地表明，在DNA合成开始之前，恶性细胞增殖需要铁。我们的结果也为进一步的研究提供了基础，这些研究将更好地确定利用DFO治疗神经母细胞瘤患者的治疗方法。
