Zhang M, Liu W, Ding D, Salvi R
Center for Hearing and Deafness, Hearing Research Laboratory, 215 Parker Hall, University at Buffalo, Buffalo, NY 14214, USA.
Neuroscience. 2003;120(1):191-205. doi: 10.1016/s0306-4522(03)00286-0.
Cisplatin, a commonly used antineoplastic agent, destroys the sensory hair cells in the cochlear and vestibular system leading to irreversible hearing loss and balance problems. Cisplatin-induced hair cell damage presumably occurs by apoptosis. Recent studies suggest that p53 may play an important role initiating cisplatin-induced apoptosis in some cell types. To determine if p53 plays a role in cisplatin-mediated hair cell loss, cochlear and utricular organotypic cultures were prepared from postnatal day 3-4 rats and treated with cisplatin or cisplatin plus pifithrin-alpha (PFT), a p53 inhibitor. Control cultures were devoid of p53 immunolabeling, caspase-1 and caspase-3 labeling and p53 protein was absent from Western blots. Cisplatin (1-10 microg/ml) caused a dose-dependent loss of hair cells in cochlear and utricular cultures, up-regulated phospho-p53 serine 15 immunolabeling, increased the expression of phospho-p53 serine 15 in Western blots from 6 to 48 h after the onset of cisplatin-treatment, and increased caspase-1 and caspase-3 labeling in cochlear and vestibular cultures. Addition of PFT (20-100 microM) to cisplatin-treated cochlear and utricular cultures resulted in a dose-dependent increase in hair cell survival; suppressed the expression of p53 in Western blots and eliminated caspase-1 and caspase-3 labeling in cultures. These results suggest that the tumor suppressor protein, p53, plays a critical role in initiating apoptosis in cochlear and vestibular hair cells. Temporary suppression of p53 with PFT provides significant protection against cisplatin-induced hair cell loss and offers the potential for reducing the ototoxic, vestibulotoxic and neurotoxic side effects of cisplatin.
顺铂是一种常用的抗肿瘤药物，它会破坏耳蜗和前庭系统中的感觉毛细胞，导致不可逆的听力丧失和平衡问题。顺铂诱导的毛细胞损伤可能是通过凋亡发生的。最近的研究表明，p53可能在某些细胞类型中启动顺铂诱导的凋亡过程中发挥重要作用。为了确定p53是否在顺铂介导的毛细胞损失中起作用，从出生后第3 - 4天的大鼠制备了耳蜗和椭圆囊器官型培养物，并用顺铂或顺铂加pifithrin-α（PFT，一种p53抑制剂）进行处理。对照培养物没有p53免疫标记、caspase-1和caspase-3标记，Western印迹中也没有p53蛋白。顺铂（1 - 10微克/毫升）导致耳蜗和椭圆囊培养物中的毛细胞呈剂量依赖性损失，上调了磷酸化p53丝氨酸15免疫标记，在顺铂处理开始后6至48小时内，Western印迹中磷酸化p53丝氨酸15的表达增加，并且耳蜗和前庭培养物中的caspase-1和caspase-3标记增加。向顺铂处理的耳蜗和椭圆囊培养物中添加PFT（20 - 100微摩尔）导致毛细胞存活率呈剂量依赖性增加；抑制了Western印迹中p53的表达，并消除了培养物中的caspase-1和caspase-3标记。这些结果表明，肿瘤抑制蛋白p53在启动耳蜗和前庭毛细胞凋亡中起关键作用。用PFT暂时抑制p53可显著保护免受顺铂诱导的毛细胞损失，并有可能减少顺铂的耳毒性、前庭毒性和神经毒性副作用。
