Article

6 METTL16 S-glutathionylation-triggered RNA m A modification of IGF2BP3 inhibits CFTR expression and promotes chemoresistance in colorectal cancer

Lu Xu1,2,3, Yan Ma1, Wang Yao1, Ya-ju Qiu1, Chao Xu1,3,4,5, Fang-yue Xu1,6, Zhi-miao Zou1,7, Wu-min Dai1,7, Wan-gang Gong1, De-ning Ma1, Xiao-wan Chen1,8, Wen-kai Ye1,6, Yi-yun Huang1,6, Hai-tao Chen1,3,4,5, Lue Hong1,9, Jia-ping Mo1, Jian-guo Feng1,7, En-yan Yu1, Wei Chen1,7,8, Yu-hua Zhang1,6, Qing-hua Yao1,2,3,4,5, Xia Li1,6,7,8
1 Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou 310022, China
2 State Key Laboratory of Quality Research in Chinese Medicine & Faculty of Chinese Medicine, Macau University of Science and Technology, Macao 999078, China
3 Department of Oncology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Xinhua Hospital of Zhejiang Province, Hangzhou 310005, China
4 Key Laboratory for Research on the Pathogenesis of ‘Inflammation-Cancer Transformation’ in Intestinal Diseases, Hangzhou 310005, China
5 Zhejiang Engineering Research Center of Intelligent Equipment of Chronic Chinese and Western Medicine, Hangzhou 310005, China
6 The Second School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou 310053, China
7 Zhejiang Cancer Research Institute, Zhejiang Cancer Hospital, Hangzhou 310022, China
8 Postgraduate Training Base Alliance of Wenzhou Medical University (Zhejiang Cancer Hospital), Hangzhou 310022, China
9 The First School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou 310053, China
Correspondence to: Wei Chen: chenwei@zjcc.org.cn, Yu-hua Zhang: zhangyuhua1013@126.com, Qing-hua Yao: 20234052@zcmu.edu.cn, Xia Li: lixia@zjcc.org.cn,
DOI: 10.1038/s41401-026-01821-w
Received: 21 August 2025
Accepted: 9 April 2026
Advance online: 20 May 2026

Abstract

5-Fluorouracil (5-FU) resistance in colorectal cancer (CRC) involves oxidative stress mechanisms, but the role of epitranscriptomic regulation remains unclear. This study investigates how oxidative post-translational modifications of the N6-methyladenosine (m6A) methyltransferase METTL16 contribute to 5-FU resistance. Parental (HCT8, HCT15) and 5-FU-resistant CRC cells were compared using redox proteomics, m6A-seq, RNA-seq, and functional assays. METTL16 S-glutathionylation was assessed via streptavidin pulldown and mass spectrometry. IGF2BP3’s role was validated through knockdown/overexpression, patient-derived organoids (PDOs), and xenograft models. Clinical relevance was evaluated in 112 CRC patient tissues and data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Drug synergy was tested using isoliquiritigenin (ISO) combined with 5-FU. Resistant cells exhibited elevated global protein S-glutathionylation and reduced m6A RNA methylation. METTL16 underwent site- specific S-glutathionylation at Cys548, leading to its degradation and subsequent m6A loss. Integrative omics identified IGF2BP3 as a key METTL16 target: reduced m6A on IGF2BP3 mRNA enhanced its nuclear export, splicing, and overexpression. IGF2BP3 knockdown sensitized resistant cells to 5-FU in vitro and in vivo, while overexpression conferred resistance. Mechanistically, IGF2BP3 destabilized CFTR mRNA (an ABC transporter), reducing 5-FU uptake. Clinically, high IGF2BP3 correlated with poor survival and 5-FU resistance in CRC patients. Targeting IGF2BP3 with ISO synergized with 5-FU, overcoming resistance in cells and xenografts. Oxidative stress-induced METTL16 S-glutathionylation drives 5-FU resistance by reducing m6A modification, enabling IGF2BP3 overexpression and CFTR suppression. IGF2BP3 is a biomarker of clinical resistance, and its targeting with ISO represents a promising combinatorial strategy to restore 5-FU efficacy in CRC.
Keywords: IGF2BP3; METTL16; S-glutathionylation; CFTR; isoliquiritigenin; colorectal cancer

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