Division of Biochemical Toxicology, National Center for Toxicological Research, 3900 NCTR Rd, Jefferson, AR, 72079, USA.
Division of Biochemical Toxicology, National Center for Toxicological Research, 3900 NCTR Rd, Jefferson, AR, 72079, USA; Department of Internal Medicine, Division of Molecular Medicine, Program in Cancer Genetics, Epigenetics and Genomics, University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, 87131, USA.
Food Chem Toxicol. 2018 Nov;121:214-223. doi: 10.1016/j.fct.2018.08.034. Epub 2018 Aug 26.
The increasing number of man-made chemicals in the environment that may pose a carcinogenic risk highlights the need for developing reliable time- and cost-effective approaches for carcinogen detection and identification. To address this issue, we investigated the utility of high-throughput microarray gene expression and next-generation genome-wide DNA methylation sequencing for the in vitro identification of genotoxic and non-genotoxic carcinogens. Terminally differentiated and metabolically competent human liver HepaRG cells were treated at minimally cytotoxic concentrations of (i) the genotoxic human liver carcinogen aflatoxin B (AFB1) and its structural non-carcinogenic analog aflatoxin B (AFB2); (ii) the genotoxic human lung carcinogen benzo[a]pyrene (B[a]P) and its non-carcinogenic isomer benzo[e]pyrene (B[e]P); and (iii) the non-genotoxic liver carcinogen methapyrilene for 72 h and transcriptomic and DNA methylation profiles were examined. Treatment of HepaRG cells with the liver carcinogens AFB1 and methapyrilene generated distinct gene-expression profiles, whereas B[a]P had only a slight effect on gene expression. In contrast to transcriptomic alterations, treatment of HepaRG cells with the carcinogenic and non-carcinogenic chemicals resulted in profound changes in the DNA methylation footprint; however, the correlation between gene-specific DNA methylation and gene expression changes was minimal. Among the carcinogen-altered genes, transferrin (TF) emerged as sensitive marker for an initial screening of chemicals for their potential liver carcinogenicity. Potential liver carcinogens (i.e., chemicals causing altered TF gene expression) could then be subjected to gene-expression analyses to differentiate genotoxic from non-genotoxic liver carcinogens. This approach may substantially enhance the identification and assessment of potential liver carcinogens.
环境中越来越多的人为化学物质可能具有致癌风险，这突出表明需要开发可靠的、省时省钱的方法来检测和识别致癌物。为了解决这个问题，我们研究了高通量微阵列基因表达和下一代全基因组 DNA 甲基化测序在体外鉴定遗传毒性和非遗传毒性致癌物的应用。在最低细胞毒性浓度下，用（i）遗传毒性人类肝癌致癌物黄曲霉毒素 B（AFB1）及其结构非致癌类似物黄曲霉毒素 B2（AFB2）；（ii）遗传毒性人类肺癌致癌物苯并[a]芘（B[a]P）及其非致癌异构体苯并[e]芘（B[e]P）；（iii）非遗传毒性肝癌致癌物甲吡咯烷处理终末分化和代谢功能健全的人肝 HepaRG 细胞 72 小时，并检查转录组和 DNA 甲基化谱。用肝致癌物 AFB1 和甲吡咯烷处理 HepaRG 细胞会产生独特的基因表达谱，而 B[a]P 对基因表达只有轻微影响。与转录组改变相反，用致癌和非致癌化学物质处理 HepaRG 细胞会导致 DNA 甲基化足迹发生深刻变化；然而，基因特异性 DNA 甲基化和基因表达变化之间的相关性很小。在致癌物质改变的基因中，转铁蛋白（TF）作为一种敏感标志物，可用于对潜在的肝脏致癌性进行初步筛选。潜在的肝脏致癌物（即引起 TF 基因表达改变的化学物质）可进一步进行基因表达分析，以区分遗传毒性和非遗传毒性的肝脏致癌物。这种方法可以大大提高潜在肝脏致癌物的识别和评估。
