Zou Shaomin, Huang Yizhi, Yang Ziqing, Zhang Jieping, Meng Manqi, Zhang Yijing, Feng Junyan, Sun Rui, Li Weiyao, Wang Wencong, López Jesús García-Foncillas, Fang Lekun
Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Clin Transl Med. 2024 Mar;14(3):e1621. doi: 10.1002/ctm2.1621.
NOP2/Sun domain 2 (NSUN2) is one of the important RNA methyltransferases catalyzing 5-methylcytosine (m5C) formation and participates in many critical bioprocesses. However, the roles and underlying molecular mechanisms of NSUN2-mediated m5C modification in colorectal cancer (CRC) remain unclear.
To explore the NSUN2 expression in CRC, fresh tissue samples were collected and Nsun2 knockout mouse was constructed. In vitro and in vivo functional assays were conducted to assess the role of NSUN2. RNA array and bisulfite sequencing were used to investigate the potential targets. The mechanisms of NSUN2 function on SKIL were identified by m5C-methylated-RNA immunoprecipitation and RNA stability assays. Additionally, tissue microarray analysis was conducted and patient-derived tumour xenograft mouse (PDX) models were used to define the potential therapeutic targets.
NSUN2 was highly expressed in CRC and correlated with poor CRC patient survival. Moreover, silencing NSUN2 suppressed CRC tumourigenesis and progression in Nsun2 knockout mouse models. In vitro and in vivo studies suggested that NSUN2 promoted colorectal cancer cell growth. Mechanistically, SKI-like proto-oncogene (SKIL) is positively regulated by NSUN2, and the NSUN2-SKIL axis is clinically relevant to CRC. NSUN2 induced m5C modification of SKIL and stabilized its mRNA, which was mediated by Y-box binding protein 1 (YBX1). Elevated SKIL levels increased transcriptional coactivator with PDZ-binding motif (TAZ) activation.
Our findings highlight the importance of NSUN2 in the initiation and progression of CRC via m5C-YBX1-dependent stabilization of the SKIL transcript, providing a promising targeted therapeutic strategy for CRC.
NOP2/太阳结构域蛋白2（NSUN2）是催化5-甲基胞嘧啶（m5C）形成的重要RNA甲基转移酶之一，并参与许多关键生物过程。然而，NSUN2介导的m5C修饰在结直肠癌（CRC）中的作用及潜在分子机制仍不清楚。
为探究NSUN2在CRC中的表达，收集新鲜组织样本并构建Nsun2基因敲除小鼠。进行体外和体内功能试验以评估NSUN2的作用。采用RNA阵列和亚硫酸氢盐测序研究潜在靶点。通过m5C甲基化RNA免疫沉淀和RNA稳定性试验确定NSUN2对SKIL发挥功能的机制。此外，进行组织芯片分析并使用患者来源的肿瘤异种移植小鼠（PDX）模型确定潜在治疗靶点。
NSUN2在CRC中高表达，且与CRC患者的不良生存相关。此外，在Nsun2基因敲除小鼠模型中，沉默NSUN2可抑制CRC的肿瘤发生和进展。体外和体内研究表明，NSUN2促进结肠癌细胞生长。机制上，SKI样原癌基因（SKIL）受NSUN2正向调控，且NSUN2-SKIL轴在临床上与CRC相关。NSUN2诱导SKIL的m5C修饰并使其mRNA稳定，这由Y盒结合蛋白1（YBX1）介导。SKIL水平升高会增加含PDZ结合基序的转录共激活因子（TAZ）的活性。
我们的研究结果突出了NSUN2通过m5C-YBX1依赖的SKIL转录本稳定作用在CRC起始和进展中的重要性，为CRC提供了一种有前景的靶向治疗策略。
