Gill J S, Windebank A J
Molecular Neuroscience Program, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
J Clin Invest. 1998 Jun 15;101(12):2842-50. doi: 10.1172/JCI1130.
Platinum compounds induce apoptosis in malignant cells and are used extensively in the treatment of cancer. Total dose is limited by development of a sensory neuropathy. We now demonstrate that when rats are administered cisplatin (2 mg/kg i.p. for 5 d), primary sensory neurons in the dorsal root ganglion die by apoptosis. This was reproduced by exposure of dorsal root ganglion neurons and PC12 cells to cisplatin (3 microg/ml) in vitro. Apoptosis was confirmed by electron microscopy, DNA laddering, and inhibition by the caspase inhibitor z-VAD.fmk (100 microM). Cell death in vitro was preceded by upregulation of cyclin D1, cdk4, and increased phosphorylation of retinoblastoma protein; all are indicators of cell cycle advancement. The level of p16(INK4a), an endogenous inhibitor of the cyclin D1/cdk4 complex decreased. Exposure of PC12 cells and dorsal root ganglion neurons to increased levels of nerve growth factor (100 ng/ ml) prevented both apoptosis and upregulation of the cell cycle markers. Cancer cells without nerve growth factor receptors (gp140TrkA) were not protected by the neurotrophin. This indicated that cisplatin may kill cancer cells and neurons by a similar mechanism. In postmitotic neurons, this involves an attempt to re-enter the cell cycle resulting in apoptosis which is specifically prevented by nerve growth factor.
铂类化合物可诱导恶性细胞凋亡，广泛用于癌症治疗。总剂量受感觉神经病变发展的限制。我们现在证明，当给大鼠腹腔注射顺铂（2毫克/千克，连续5天）时，背根神经节中的初级感觉神经元会因凋亡而死亡。体外将背根神经节神经元和PC12细胞暴露于顺铂（3微克/毫升）可重现这一现象。通过电子显微镜、DNA梯状条带分析以及半胱天冬酶抑制剂z-VAD.fmk（100微摩尔）的抑制作用证实了凋亡。体外细胞死亡之前，细胞周期蛋白D1、细胞周期蛋白依赖性激酶4上调，视网膜母细胞瘤蛋白磷酸化增加；这些都是细胞周期进展的指标。细胞周期蛋白D1/细胞周期蛋白依赖性激酶4复合物的内源性抑制剂p16(INK4a)水平降低。将PC12细胞和背根神经节神经元暴露于增加水平的神经生长因子（100纳克/毫升）可防止凋亡和细胞周期标志物的上调。没有神经生长因子受体（gp140TrkA）的癌细胞不受神经营养因子的保护。这表明顺铂可能通过类似机制杀死癌细胞和神经元。在有丝分裂后神经元中，这涉及试图重新进入细胞周期，导致凋亡，而神经生长因子可特异性阻止这种凋亡。
