Zhou Jiaxin, Xiong Rui, Zhou Jiazhen, Guan Xinchao, Jiang Guanqing, Chen Yuyang, Yang Qiaoyuan
The Institute for Chemical Carcinogenesis, Guangzhou Medical University, Xinzao, Panyu District, Guangzhou 511436, China.
School of Anesthesiology, Southern Medical University, 1023-1063 Shatai Nan Road, Baiyun District, Guangzhou 510515, China.
Toxicol Appl Pharmacol. 2022 Feb 1;436:115849. doi: 10.1016/j.taap.2021.115849. Epub 2021 Dec 30.
Nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a Group 1 human carcinogen, as classified by the International Agency for Research of Cancer (IARC), and plays a significant role in lung carcinogenesis. However, its carcinogenic mechanism has not yet been fully elucidated. In this study, we performed colony formation assays, soft-agar assays, and tumor growth in nude mice to show that 100 mg/L NNK facilitates the malignant transformation of human bronchial epithelial Beas-2B cells. Transcriptome sequencing showed that insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), a post-transcriptional regulator, was differentially expressed in NNK-induced malignant transformed Beas-2B cells (2B-NNK cells). Small interfering RNA (SiRNA) was used to downregulate the expression of the IGF2BP1 gene. The reduction in protein expression, cell proliferation rate, and colony-forming ability and the increase in the apoptosis rate of Beas-2B cells transfected with the SiRNA indicated a role for IGF2BP1 in NNK-induced malignant transformation. IGF2BP1 is an N6-methyladenosine (m6A) regulatory factor, but it is not known whether its association with m6A mediates the malignant transformation of cells. Therefore, we measured the overall levels of m6A in Beas-2B cells. We found that the overall m6A level was lower in 2B-NNK cells, and knocking down IGF2BP1, the overall level of m6A was restored. Hence, we concluded that IGF2BP1 is involved in the NNK-induced malignant transformation of Beas-2B cells, possibly via m6A modification. This study therefore contributes novel insights into the environmental pathogenesis of lung cancer and the gene regulatory mechanisms of chemical carcinogenesis.
亚硝胺4-（甲基亚硝基氨基）-1-（3-吡啶基）-1-丁酮（NNK）是国际癌症研究机构（IARC）分类的1类人类致癌物，在肺癌发生中起重要作用。然而，其致癌机制尚未完全阐明。在本研究中，我们进行了集落形成试验、软琼脂试验和裸鼠肿瘤生长试验，以表明100mg/L的NNK促进人支气管上皮Beas-2B细胞的恶性转化。转录组测序显示，胰岛素样生长因子2 mRNA结合蛋白1（IGF2BP1），一种转录后调节因子，在NNK诱导的恶性转化Beas-2B细胞（2B-NNK细胞）中差异表达。使用小干扰RNA（SiRNA）下调IGF2BP1基因的表达。用SiRNA转染的Beas-2B细胞中蛋白质表达、细胞增殖率和集落形成能力的降低以及凋亡率的增加表明IGF2BP1在NNK诱导的恶性转化中起作用。IGF2BP1是一种N6-甲基腺苷（m6A）调节因子，但尚不清楚其与m6A的关联是否介导细胞的恶性转化。因此，我们测量了Beas-2B细胞中m6A的总体水平。我们发现2B-NNK细胞中的总体m6A水平较低，敲低IGF2BP1后，m6A的总体水平得以恢复。因此，我们得出结论，IGF2BP1可能通过m6A修饰参与NNK诱导的Beas-2B细胞恶性转化。因此，本研究为肺癌的环境发病机制和化学致癌的基因调控机制提供了新的见解。
