BACKGROUND F508del is prototypical of Class 2 CFTR mutations associated with protein misprocessing and reduced function. Corrector compounds like lumacaftor partially rescue the processing defect of F508del-CFTR whereas potentiators like ivacaftor, enhance its channel activity once trafficked to the cell surface. We asked if emerging modulators developed for F508del-CFTR can rescue Class 2 mutations previously shown to be poorly responsive to lumacaftor and ivacaftor. METHODS Rescue of mutant CFTRs by the correctors: AC1, AC2-1 or AC2-2 and the potentiator, AP2, was studied in HEK-293 cells and in primary human nasal epithelial (HNE) cultures, using a membrane potential assay and Ussing chamber, respectively. RESULTS In HEK-293 cells, we found that a particular combination of corrector molecules (AC1 plus AC2-1) and a potentiator (AP2) was effective in rescuing both the misprocessing and reduced function of M1101K and G85E respectively. These findings were recapitulated in patient-derived nasal cultures, although another corrector combination, AC1 plus AC2-2 also improved misprocessing in these primary tissues. Interestingly, while this corrector combination only led to a modest increase in the abundance of mature N1303K-CFTR it did enable its functional expression in the presence of the potentiator, AP2, in part, because the nominal corrector, AC2-2 also exhibits potentiator activity. CONCLUSIONS Strategic combinations of novel modulators can potentially rescue Class 2 mutants thought to be relatively unresponsive to lumacaftor and ivacaftor.

中文翻译：

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为 F508del-CFTR 开发的新兴临床前调节剂有可能对 ORKAMBI 抗性加工突变体有效

背景 F508del 是与蛋白质错误加工和功能降低相关的 2 类 CFTR 突变的原型。像 lumacaftor 这样的校正剂化合物部分地挽救了 F508del-CFTR 的加工缺陷，而像 ivacaftor 这样的增强剂在运输到细胞表面后会增强其通道活性。我们询问为 F508del-CFTR 开发的新兴调节剂是否可以挽救先前显示对 lumacaftor 和 ivacaftor 反应不佳的 2 类突变。方法 在 HEK-293 细胞和原代人鼻上皮 (HNE) 培养物中，使用膜电位测定和 Ussing 室研究了通过校正剂 AC1、AC2-1 或 AC2-2 和增效剂 AP2 拯救突变 CFTR ， 分别。结果在 HEK-293 细胞中，我们发现校正分子（AC1 加 AC2-1）和增效剂 (AP2) 的特定组合可分别有效地挽救 M1101K 和 G85E 的错误处理和功能降低。这些发现在源自患者的鼻腔培养物中得到了概括，尽管另一种校正剂组合 AC1 加 AC2-2 也改善了这些原始组织中的错误处理。有趣的是，虽然这种校正剂组合仅导致成熟 N1303K-CFTR 丰度的适度增加，但它确实能够在增强剂 AP2 存在下实现其功能表达，部分原因是名义校正剂 AC2-2 也表现出增强剂活性. 结论 新型调节剂的战略组合可以潜在地拯救被认为对 lumacaftor 和 ivacaftor 相对无反应的 2 类突变体。