Repurposing an FDA Approved Drug, B-Raf Inhibitor Dabrafenib, for Protection from Cisplatin- and Noise-Induced Hearing Loss

项目摘要/摘要 噪音、衰老、抗生素和化疗导致的听力损失影响着7亿人 在世界范围内，但还没有FDA批准的药物来预防它。这项提案是为了优化FDA批准的 口服生物可用小分子B-Raf激酶抑制剂达普拉非尼(Tafinlar)，以预防或治疗顺铂- 和噪声性听力损失(分别为CIHL和NIHL)。充分利用以下方面的显著重叠 在CIHL和NIHL中激活的分子通路，4385个生物活性的无偏高通量筛选 化合物(Teitz等人，2018)和187种高度特异的激酶抑制剂(未发表)，可减少顺铂- 在内耳细胞系(HEI-OC1)的诱导细胞死亡中，达普拉非尼是最好的靶点。达普拉非尼是一种强效的 选择性B-Raf激酶小分子抑制剂治疗晚期黑色素瘤和非小细胞肺 癌症。该药对顺铂诱导的毛细胞死亡有保护作用，IC50为30 nM，治疗指数为 &gt；2000，比其他四种基准耳保护剂(硫代硫酸钠、依贝赛林、D-硫代硫酸钠)好70-3,280倍 蛋氨酸和地塞米松；初步数据和Teitz等人，JEM 2018)。三种额外的B-Raf抑制剂 两种MEK1/2抑制剂(直接位于B-Raf激酶下游)也能阻止顺铂诱导的毛细胞 耳蜗外植体死亡。此外，口服达普拉非尼对慢性淋巴细胞性白血病小鼠模型有显著的保护作用。 和NIHL。给小鼠服用达普拉非尼的日剂量在批准的慢性人类剂量范围内。 治疗(6-12个月)。因此，我们假设达普拉非尼可以迅速用于口服。 给人类，以预防CIHL和NIHL。因为达普拉非尼的临床前和临床毒性图谱已经 经FDA批准，拟议的工作重点是必要的非临床实验，以确定 达普拉非尼加速转化为临床使用的有效性，使患有CIHL和NIHL的高危患者受益。 测试不同的时间表以防止CIHL和NIHL，如本提案中所述，将允许识别 最重要的人体临床试验方案。这项研究还将揭示一种新的细胞途径和分子 靶向B-Raf激酶用于耳保护。这些研究的完成将导致FDA的第一批- 经批准的用于预防和治疗听力损失的药物。

PROJECT SUMMARY/ABSTRACT Hearing loss caused by noise, aging, antibiotics and chemotherapy affects seven hundred million people worldwide, yet there are no FDA-approved drugs to prevent it. This proposal is to optimize an FDA-approved, orally bioavailable small molecule B-Raf kinase inhibitor, dabrafenib (TAFINLAR), to prevent or treat cisplatin- and noise-induced hearing loss (CIHL and NIHL, respectively). Taking advantage of the significant overlap in the molecular pathways activated in CIHL and NIHL, unbiased high-throughput screens of 4,385 bioactive compounds (Teitz et al., 2018) and 187 highly-specific kinase inhibitors (unpublished) that reduced cisplatin- induced cell-death in an inner ear cell line (HEI-OC1) revealed dabrafenib as the best hit. Dabrafenib is a potent selective small molecule inhibitor of B-Raf kinase for treating advanced melanoma and non-small cell lung carcinoma. This drug prevented cisplatin-induced hair cell death in vitro, with IC50 of 30 nM and therapeutic index >2000, and 70-3,280 times better than four other benchmark otoprotectants (sodium thiosulfate, ebselen, D- methionine and dexamethasone; preliminary data and Teitz et al., JEM 2018). Three additional B-Raf inhibitors and two MEK1/2 inhibitors (directly downstream from B-Raf kinase) also prevented cisplatin-induced hair cell death in cochlear explants. Furthermore, oral dabrafenib provided significant protection in mouse models of CIHL and NIHL. The daily dose of dabrafenib administered to mice was in the range approved for chronic human treatment (6-12 months). Therefore, we hypothesize that dabrafenib can be rapidly repurposed for oral delivery to humans to prevent CIHL and NIHL. Because preclinical and clinical toxicity profiles of dabrafenib are already approved by FDA, the proposed work focuses on the necessary nonclinical experiments for determining dabrafenib’s efficacy for expedited translation into clinical use to benefit patients at high risk of CIHL and NIHL. Testing the different schedules to prevent CIHL and NIHL as described in this proposal will allow to identify the most important regimens for human clinical trials. The study will also reveal a new cellular pathway and molecular target B-Raf kinase for otoprotection. The completion of the studies will lead to one of the first FDA- approved drugs repurposed for the prevention and treatment of hearing loss.