Repurposing FDA-Approved MEK Inhibitor Trametinib for Protection Against Cisplatin-Induced Hearing Loss

项目摘要/摘要 顺铂耳毒性引起的听力损失影响40-60%的化疗患者，导致听力下降 生活质量和令人衰弱的语言障碍，但没有食品和药物管理局(FDA)批准 治疗目前是可用的。目前在临床前和临床试验中的化合物只提供了部分 保护或与危及生命的副作用有关，因此显然需要替代治疗 策略。最近，BRAF抑制剂达普拉非尼在体内被发现对顺铂的毒性有保护作用 以临床上相关的剂量给药。丝裂原活化蛋白激酶(MAPK)的其他抑制剂 在耳蜗外植体模型中，包括MEK抑制剂曲美替尼在内的通路也对顺铂毒性具有保护作用。 重要的是，达普拉非尼和曲美替尼的组合被fda批准用于黑色素瘤的治疗，并可能 被快速追踪治疗顺铂引起的听力损失。这些化合物对大脑也很有效。 转移，表明它们穿过血脑屏障，这类似于血液迷宫屏障在 耳朵。因此，我们假设曲美替尼在体内对顺铂引起的耳毒性有保护作用。 与达普拉非尼联合使用可提供更强的保护。在目标1中，我们将确定MEK是否 曲美替尼抑制剂在小鼠模型中对顺铂诱导的耳毒性具有保护作用。我们将测试一下 口服曲美替尼减轻CBA小鼠模型顺铂耳毒性的临床相关多剂量，多剂量，多剂量 循环治疗模式。听力损失将通过测量听性脑干反应(ABR)和 失真产物耳声发射(DPOAE)阈值漂移及形态分析 耳蜗生毛细胞、支持细胞、血管纹和神经节。曲美替尼介导的MAPK通路的验证 通过对成年小鼠耳蜗行免疫染色，可获得抑制作用。确认曲美替尼跨过 上述免疫染色和质谱学(LC-MS)实现的血迷路屏障 曲美替尼处理小鼠的外淋巴样本。在目标2中，确定曲美替尼和曲美替尼的组合 达普拉非尼增强了对顺铂所致耳毒性的保护作用，我们将测试该药物组合的 对耳毒性的保护，对MAPK通路的调节，以及跨越血迷路屏障的能力 这项研究将首次研究曲美替尼的潜力，并将其与 曲美替尼联合达普拉非尼，用于预防顺铂引起的听力损失，因为我们寻求提供一种强有力的 目前没有FDA批准的治疗方法的疾病的候选治疗药物。此外，克雷顿接待了7名 经常在项目、联席会议和研讨会上进行合作的听觉研究实验室。另外， 克雷顿翻译听力中心荣获美国国立卫生研究院附属生物医学研究中心 卓越(Cobre)奖助金，将基础听力损失研究转化为实用疗法。它将允许 扩建核心设施设备以及招聘新的研究人员。因此，Creighton提供了一个 为寻求在听觉研究领域建立事业的初级科学家提供良好的环境和支持。

Project Summary/Abstract Hearing loss caused by cisplatin ototoxicity affects 40-60% of chemotherapy patients resulting in decreased quality-of-life and debilitating language barriers, yet no Food and Drug Administration (FDA)-approved treatment is currently available. Current compounds in preclinical and clinical trials provide only partial protection or are associated with life-threatening side effects, thus there is a clear need alternative treatment strategy. Recently, BRAF inhibitor dabrafenib was found to protect from cisplatin toxicity in vivo when administered at clinically relevant doses. Additional inhibitors of the mitogen-activated protein kinase (MAPK) pathway, including MEK inhibitor trametinib, also protect from cisplatin toxicity in cochlear explant models. Importantly, a combination of dabrafenib and trametinib is FDA-approved for treatment of melanoma and may be fast-tracked for treatment cisplatin-induced hearing loss. The compounds are also effective against brain metastases, revealing they cross the blood-brain barrier which is similar to the blood-labyrinth barrier in the ear. We therefore hypothesize trametinib will protect against cisplatin-induced ototoxicity in vivo and provide enhanced protection in combination with dabrafenib. In aim 1, we will determine whether MEK inhibitor trametinib confers protection from cisplatin-induced ototoxicity in mouse models. We will test whether oral trametinib mitigates cisplatin ototoxicity in CBA mouse models using a clinically relevant multi-dose, multi- cycle treatment model. Hearing loss will be determined by measuring auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) threshold shifts, along with morphological analysis of cochlear HCs, supporting cells, stria vascularis, and SGNs. Verification of trametinib-mediated MAPK pathway inhibition will be obtained by immunostaining of adult mouse cochleae. Confirmation trametinib crosses the blood-labyrinth barrier achieved by above mentioned immunostaining and Mass Spectrometry (LC-MS) of perilymph samples from trametinib treated mice. In aim 2, determine if a combination of trametinib and dabrafenib provide enhanced protection from cisplatin-induced ototoxicity We will test the drug combination’s protection from ototoxicity, regulation of the MAPK pathway, and ability to cross the blood-labyrinth barrier as described in aim 1. This study will be the first to investigate the potential of trametinib, and combination of trametinib with dabrafenib, for protection against cisplatin-induced hearing loss as we seek to provide a robust therapeutic candidate for a disorder with no current FDA-approved treatment. Moreover, Creighton hosts 7 auditory research labs who regularly collaborate on projects, joint meetings, and seminars. Additionally, Creighton’s Translational Hearing Center has been awarded an NIH-affiliated Centers of Biomedical Research Excellence (COBRE) grant to translate basic hearing loss research into practical therapies. It will allow for expansion of core facility equipment as well as recruit new research faculty. Thus, Creighton provides an excellent environment and support for junior scientists seeking to build a career in the auditory research field.