NSUN2-mediated mC modification drives alternative splicing reprogramming and promotes multidrug resistance in anaplastic thyroid cancer through the NSUN2/SRSF6/UAP1 signaling axis.
Xiukun Hou, Qiman Dong, Jie Hao, Min Liu, Junya Ning, Mei Tao, Zhongyu Wang, Fengli Guo, Dongmei Huang, Xianle Shi, Ming Gao, Dapeng Li, Xiangqian Zheng
Author Information
Xiukun Hou: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Qiman Dong: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Jie Hao: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Min Liu: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Junya Ning: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Mei Tao: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Zhongyu Wang: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Fengli Guo: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Dongmei Huang: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Xianle Shi: School of Medicine, Nankai University, Tianjin 300071, China.
Ming Gao: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Dapeng Li: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Xiangqian Zheng: Department of Thyroid and Neck Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300040, China.
Anaplastic thyroid carcinoma (ATC) is an extraordinarily aggressive form of thyroid cancer, frequently presenting with locally advanced infiltration or distant metastases at the time of initial diagnosis, thus missing the optimal window for surgical intervention. Consequently, systemic chemotherapy and targeted therapies are vital for improving the prognosis of ATC. However, ATC exhibits significant resistance to conventional treatments, highlighting the need to elucidate the biological mechanisms underlying this drug resistance and identify novel therapeutic targets to overcome it. We conducted a comprehensive analysis of both bulk and single-cell RNA sequencing (scRNA-seq) data from ATC samples to screen for mC modification-related genes associated with multidrug resistance (MDR). We then performed IC assays, flow cytometry, and employed a spontaneous tumorigenic ATC mouse model with Nsun2 knockout to demonstrate that NSUN2 promotes MDR in ATC. To investigate the mechanisms of NSUN2-mediated drug resistance, we generated NSUN2-knockout ATC cell lines and performed transcriptomic, proteomic, and MeRIP-seq analyses. Additionally, RNA sequencing and alternative splicing analyses were conducted to determine global changes upon NSUN2 knockout. We further explored the underlying mechanisms of the NSUN2/SRSF6/UAP1 axis through glycoprotein staining, denaturing IP ubiquitination, nuclear-cytoplasmic fractionation, and PCR. Lastly, we evaluated the synergistic effects of a small-molecule NSUN2 inhibitor with anticancer agents both and . Our findings reveal that NSUN2 expression correlates significantly with MDR in ATC. NSUN2 operates as a "writer" and ALYREF as a "reader" of mC on SRSF6 mRNA, inducing alternative splicing reprogramming and redirecting the splice form of the UAP1 gene from AGX1 to AGX2. As a result, AGX2 enhances the N-linked glycosylation of ABC transporters, stabilizing them by preventing ubiquitination-mediated degradation. Furthermore, an NSUN2 inhibitor reduces NSUN2 enzymatic activity and diminishes downstream target expression, presenting a novel, promising therapeutic approach to overcome MDR in ATC. These findings suggest that the NSUN2/SRSF6/UAP1 signaling axis plays a vital role in MDR of ATC and identify NSUN2 as a synergistic target for chemotherapy and targeted therapy in ATC.
