Das Samrat, Thakur Shefali, Cahais Vincent, Virard François, Claeys Liesel, Renard Claire, Cuenin Cyrille, Cros Marie-Pierre, Keïta Stéphane, Venuti Assunta, Sirand Cécilia, Ghantous Akram, Herceg Zdenko, Korenjak Michael, Zavadil Jiri
Epigenomics and Mechanisms Branch, International Agency for Research on Cancer, Lyon, France.
The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK.
bioRxiv. 2024 Oct 15:2024.10.14.618077. doi: 10.1101/2024.10.14.618077.
Chronic arsenic exposure can lead to various health issues, including cancer. Concerns have been mounting about the enhancement of arsenic toxicity through co-exposure to various prevalent lifestyle habits. Smokeless tobacco products are commonly consumed in South Asian countries, where their use frequently co-occurs with exposure to arsenic from contaminated groundwater. To decipher the molecular and cellular responses to arsenic and/or smokeless tobacco, we performed temporal multi-omics analysis of the transcriptome and DNA methylome remodelling in exposed hTERT-immortalized human normal oral keratinocytes (NOK), as well as arsenic and/or smokeless tobacco genotoxicity and mutagenicity investigations in NOK cells and in human p53 knock-in murine embryonic fibroblasts (Hupki MEF). RNAseq results from acute exposures to arsenic alone and in combination with smokeless tobacco extract revealed upregulation of genes with roles in cell cycle changes, apoptosis and inflammation responses. This was in keeping with global DNA hypomethylation affecting genes involved in the same processes in response to chronic treatment in NOK cells. At the phenotypic level, we observed a dose-dependent decrease in NOK cell viability, induction of DNA damage, cell cycle changes and increased apoptosis, with the most pronounced effects observed under arsenic and SLT co-exposure conditions. Live-cell imaging experiments indicated that the DNA damage likely resulted from induction of apoptosis, an observation validated by a lack of exome-wide mutagenesis in response to chronic exposure to arsenic and/or smokeless tobacco. In sum, our integrative omics study provides novel insights into the acute and chronic responses to arsenic and smokeless tobacco (co-)exposure, with both types of responses converging on several key mechanisms associated with cancer hallmark processes. The generated rich catalogue of molecular programs in oral cells regulated by arsenic and smokeless tobacco (co-)exposure may provide bases for future development of biomarkers for use in molecular epidemiology studies of exposed populations at risk of developing oral cancer.
长期接触砷会导致各种健康问题，包括癌症。人们越来越担心，通过同时接触各种常见的生活方式习惯会增强砷的毒性。无烟烟草制品在南亚国家很常见，在这些国家，人们经常在接触受污染地下水中的砷的同时使用无烟烟草制品。为了解析对砷和/或无烟烟草的分子和细胞反应，我们对暴露于砷的人端粒酶逆转录酶永生化人正常口腔角质形成细胞（NOK）进行了转录组和DNA甲基化组重塑的时间多组学分析，以及在NOK细胞和人p53基因敲入小鼠胚胎成纤维细胞（Hupki MEF）中进行砷和/或无烟烟草的遗传毒性和致突变性研究。单独急性暴露于砷以及与无烟烟草提取物联合暴露的RNAseq结果显示，参与细胞周期变化、凋亡和炎症反应的基因上调。这与NOK细胞长期处理后影响相同过程相关基因的全基因组DNA低甲基化一致。在表型水平上，我们观察到NOK细胞活力呈剂量依赖性下降、DNA损伤诱导、细胞周期变化和凋亡增加，在砷和无烟烟草联合暴露条件下观察到的影响最为明显。活细胞成像实验表明，DNA损伤可能是由凋亡诱导引起的，这一观察结果通过对长期暴露于砷和/或无烟烟草的全外显子组诱变缺乏得到验证。总之，我们的综合组学研究为砷和无烟烟草（联合）暴露的急性和慢性反应提供了新的见解，两种类型的反应都集中在与癌症特征过程相关的几个关键机制上。由砷和无烟烟草（联合）暴露调节的口腔细胞中生成的丰富分子程序目录可能为未来开发用于有患口腔癌风险的暴露人群分子流行病学研究的生物标志物提供基础。
