Whole genome profile of SWNCT and MWCNT vs. asbestos subchronic exposures to human small airway epithelial cells. Homo sapiens

Recent in vivo studies reported that inhaled carbon nanotube distribute in the alveolar region resulting in an acute inflammation, progressive fibrotic response and particle accumulation at the bronchoalveolar junction with low clearance. With similar biopersistence and shape as asbestos, a known lung carcinogen, growing concern has arisen for elevated risk of carbon nanotube-induced lung carcinogenesis; however few studies have evaluated long-term human health risks associated with chronic pulmonary carbon nanotube exposures compared to asbestos. To address this knowledge gap, we conducted subchronic in vitro exposures of dispersed single walled carbon nanotube, multi-walled carbon nanotube and crocidolite asbestos to human small airway epithelial cells to assess their neoplastic transformation potential. Subchronic single-, multi-walled carbon nanotube and asbestos exposures caused human lung cell neoplastic transformation exhibited by increased proliferation, anchorage-independent growth, invasion and angiogenesis. Whole genome profiling and protein expression analyses showed that carbon nanotube-induced transformation mechanism(s) was largely different from asbestos-related inflammatory signaling, suggesting specific carbon nanotube-induced carcinogenic potential. This study provides novel carbon nanotube and asbestos toxicogenomic information for risk assessment and an in vitro model to evaluate transformation potential of carbon nanotubes and other nanoparticles. Overall design: Whole genome expression profiling was conducted on human immortalized small airway epithelial cells (SAEC-hTERT) following 6 month in vitro chronic exposure to six separate treatments to assess differences in carbon nanotube (CNT) vs. asbestos potential tumorigenesis signaling. Dispersed single wall CNT (D-SWCNT), multi-wall CNT (D-MWCNT), ultrafine carbon black (D-UFCB), crocidolite asbestos (ASB) and saline (SAL) exposed cells were compared to Survanta® dispersant (DISP) passage control cells. Each treatment possessed 3 biological cDNA replicates. One technical replicate was performed per biological sample.

近期的体内（in vivo）研究表明，吸入的碳纳米管会分布于肺泡区域，引发急性炎症、进行性纤维化反应，并在支气管肺泡连接处出现颗粒蓄积且清除率极低。作为已确认的肺部致癌物，石棉具有相似的生物持久性与形态结构，因此人们对碳纳米管诱发肺癌的风险升高愈发担忧；然而相较于石棉，针对慢性肺部暴露于碳纳米管相关的长期人类健康风险的研究仍较为匮乏。为填补这一研究空白，我们对分散态单壁碳纳米管（single-walled carbon nanotube, SWCNT）、多壁碳纳米管（multi-walled carbon nanotube, MWCNT）以及青石棉开展了体外（in vitro）亚慢性暴露实验，以人类小气道上皮细胞为模型，评估三者的肿瘤转化潜能。亚慢性暴露于单壁、多壁碳纳米管及石棉后，人类肺细胞出现了肿瘤转化特征，具体表现为增殖能力增强、锚定非依赖性生长、侵袭性提升以及血管生成能力上调。全基因组分析与蛋白质表达分析结果显示，碳纳米管诱导的细胞转化机制与石棉相关的炎症信号通路存在显著差异，这表明碳纳米管具有独特的致癌潜能。本研究为风险评估提供了关于碳纳米管与石棉的全新毒理基因组学（toxicogenomic）数据，同时也为评估碳纳米管及其他纳米颗粒的转化潜能提供了体外实验模型。实验整体设计：将人类永生化小气道上皮细胞（SAEC-hTERT）进行为期6个月的体外慢性暴露，共设置6组不同处理，随后开展全基因组表达谱分析，以对比碳纳米管（CNT）与石棉的肿瘤发生信号通路差异。将暴露于分散态单壁碳纳米管（D-SWCNT）、分散态多壁碳纳米管（D-MWCNT）、超细炭黑（D-UFCB）、青石棉（ASB）与生理盐水（SAL）的细胞，与以Survanta®分散剂（DISP）作为传代对照的细胞进行对比。每组处理设置3个生物学重复cDNA样本，每个生物学样本均进行1次技术重复。