University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal.
Department of Pediatrics, 2nd Faculty of Medicine, Charles University and University Hospital Motol, V Uvalu 84,Prague 5, 150 06 Prague, Czech Republic.
Biochim Biophys Acta Mol Basis Dis. 2020 Nov 1;1866(11):165905. doi: 10.1016/j.bbadis.2020.165905. Epub 2020 Jul 28.
For most of the >2000 CFTR gene variants reported, neither the associated disease liability nor the underlying basic defect are known, and yet these are essential for disease prognosis and CFTR-based therapeutics. Here we aimed to characterize two ultra-rare mutations - 1717-2A > G (c.1585-2A > G) and S955P (p.Ser955Pro) - as case studies for personalized medicine.
Patient-derived rectal biopsies and intestinal organoids from two individuals with each of these mutations and F508del (p.Phe508del) in the other allele were used to assess CFTR function, response to modulators and RNA splicing pattern. In parallel, we used cellular models to further characterize S955P independently of F508del and to assess its response to CFTR modulators.
Results in both rectal biopsies and intestinal organoids from both patients evidence residual CFTR function. Further characterization shows that 1717-2A > G leads to alternative splicing generating <1% normal CFTR mRNA and that S955P affects CFTR gating. Finally, studies in organoids predict that both patients are responders to VX-770 alone and even more to VX-770 combined with VX-809 or VX-661, although to different levels.
This study demonstrates the high potential of personalized medicine through theranostics to extend the label of approved drugs to patients with rare mutations.
对于已报道的 >2000 种 CFTR 基因突变中的大多数，相关疾病易感性和潜在的基本缺陷都尚不清楚，而这些对于疾病预后和基于 CFTR 的治疗至关重要。在此，我们旨在将两个超罕见突变（1717-2A>G[c.1585-2A>G]和 S955P[p.Ser955Pro]）作为个体化医学的案例研究进行分析。
我们使用来自这两个突变个体的患者衍生直肠活检组织和肠类器官，以及另一个等位基因的 F508del[p.Phe508del]，来评估 CFTR 功能、对调节剂的反应和 RNA 剪接模式。同时，我们使用细胞模型进一步分析 S955P 独立于 F508del 的情况，并评估其对 CFTR 调节剂的反应。
两个患者的直肠活检组织和肠类器官均证实存在残留 CFTR 功能。进一步的特征表明，1717-2A>G 导致替代剪接，生成 <1%的正常 CFTR mRNA，而 S955P 影响 CFTR 门控。最后，类器官研究预测这两个患者均单独对 VX-770 有反应，甚至对 VX-770 联合 VX-809 或 VX-661 的反应更明显，尽管反应程度不同。
这项研究通过治疗诊断学展示了个体化医学的巨大潜力，能够将已批准药物的适应证扩展到携带罕见突变的患者。
