Antisense oligonucleotide targeting the E3 ligase RFFL potentiates CFTR modulator efficacy in CF primary bronchial epithelial cells

Daichi Hinata; Yukari Kai; Ryosuke Fukuda; Yuka Kamada; Yuuya Kasahara; Kiyomi Sasaki; Tokuyuki Yoshida; Satoshi Obika; Takao Inoue; Tsukasa Okiyoneda

doi:10.1016/j.omtn.2025.102756

Antisense oligonucleotide targeting the E3 ligase RFFL potentiates CFTR modulator efficacy in CF primary bronchial epithelial cells

Mol Ther Nucleic Acids. 2025 Oct 31;36(4):102756. doi: 10.1016/j.omtn.2025.102756. eCollection 2025 Dec 9.

Authors

Affiliations

¹ Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, Hyogo 669-1330, Japan.
² National Institutes of Biomedical Innovation, Health and Nutrition, Osaka 567-0085, Japan.
³ Graduate School of Pharmaceutical Sciences, The University of Osaka, Osaka 565-0871, Japan.
⁴ Division of Molecular Target and Gene Therapy Products, National Institute of Health Sciences, Kawasaki, Kanagawa 210-9501, Japan.

Abstract

Cystic fibrosis (CF) is most commonly caused by the ΔF508 mutation in the CFTR gene, leading to misfolding and degradation of the CFTR protein. Although CFTR modulators such as elexacaftor/tezacaftor/ivacaftor (ETI) provide clinical benefit, their efficacy is limited, particularly in patients with rare or poorly responsive CFTR mutations. RFFL, an E3 ubiquitin ligase, plays a central role in peripheral quality control of CFTR, reducing its plasma membrane (PM) expression and attenuating the effects of modulators. Here, we developed antisense oligonucleotides (ASOs) containing artificial nucleic acids to selectively suppress RFFL expression. An optimized RFFL-targeting ASO enhanced the efficacy of CFTR modulators by increasing the functional PM expression of ΔF508-CFTR in primary human bronchial epithelial (CF-HBE) cells derived from CF patients. Notably, the ASO also potentiated the effects of ETI on CFTR mutants associated with rare forms of CF, including those with limited responsiveness to modulators. In some cases, the ASO alone restored CFTR levels to those achieved by ETI treatment. These findings establish RFFL-targeting ASOs as first-in-class CFTR stabilizers and highlight their potential as a nucleic acid-based therapeutic strategy for CF caused by both common and rare CFTR mutations.

Keywords: ASO; CF; CFTR; MT: Oligonucleotides: Therapies and Applications; RFFL; antisense oligonucleotide; cystic fibrosis; cystic fibrosis transmembrane conductance regulator; ubiquitin ligase.