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Benchmark Dose Modeling Approaches for Volatile Organic Chemicals using a Novel Air-Liquid Interface In Vitro Exposure System

ABSTRACT: Inhalation is the most relevant route of volatile organic chemical (VOC) exposure; however, due to unique challenges posed by their chemical properties and poor solubility in aqueous solutions, in vitro chemical safety testing is predominantly performed using direct application dosing/submerged exposures. To address the difficulties in screening toxic effects of VOCs, our cell culture exposure system permits cells to be exposed to multiple concentrations at air-liquid interface (ALI) in a 24-well format. ALI exposure methods permit direct chemical-to-cell interaction with the test article at physiological conditions. In the present study, BEAS-2B and primary normal human bronchial epithelial cells (pHBEC) are used to assess gene expression, cytotoxicity, and cell viability responses to a variety of volatile chemicals including acrolein, formaldehyde, 1,3-butadiene, acetaldehyde, 1-bromopropane, carbon tetrachloride, dichloromethane, and trichloroethylene. BEAS-2B cells were exposed to all the test agents, while pHBECs were only exposed to the latter four listed above. The VOC concentrations tested elicited only slight cell viability changes in both cell types. Gene expression changes were analyzed using benchmark dose (BMD) modeling. The BMD for the most sensitive gene set was within one order of magnitude of the threshold-limit value reported by the American Conference of Governmental Industrial Hygienists, and the most sensitive gene sets impacted by exposure correlate to known adverse health effects recorded in epidemiologic and in vivo exposure studies. Overall, our study outlines a novel in vitro approach for evaluating molecular-based points-of-departure in human airway epithelial cell exposure to volatile chemicals.

ORGANISM(S): Homo sapiens

PROVIDER: GSE199794 | GEO | 2022/04/17

REPOSITORIES: GEO

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Project description:As environmental pollutants and possible carcinogens, carbon nanotubes (CNTs) have recently been found to promote tumorigenesis and tumor metastasis after long-term pulmonary exposure. However, whether CNT-induced carcinogenesis can be inherited and last for generations remains unknown. Here, we establish a post-chronic single-walled carbon nanotubes (SWCNTs) exposed human bronchial epithelium BEAS-2B cell model to investigate SWCNTs-induced carcinogenesis. At a tolerated sublethal dose level, post-chronic SWCNTs exposure significantly increases the migration and colony formation abilities of BEAS-2B cells, leading to cell malignant transformation. Notably, the malignant transformation of BEAS-2B cells is irreversible within 60 days recovery period after SWCNTs exposure, and the malignant transformation activities of cells gradually increase during the recovery period. Mechanism analyses show that post-chronic exposure to SWCNTs causes substantial DNA methylation and transcriptome dysregulation of BEAS-2B cells. Subsequent enrichment and clinical database analyses reveal that differentially expressed/methylated genes of BEAS-2B cells are enriched in cancer-related biological pathways, and several of these genes are validated in lung cancer patients. As environmental pollutants and possible carcinogens, carbon nanotubes (CNTs) have recently been found to promote tumorigenesis and tumor metastasis after long-term pulmonary exposure. However, whether CNT-induced carcinogenesis can be inherited and last for generations remains unknown. Here, we establish a post-chronic single-walled carbon nanotubes (SWCNTs) exposed human bronchial epithelium BEAS-2B cell model to investigate SWCNTs-induced carcinogenesis. At a tolerated sublethal dose level, post-chronic SWCNTs exposure significantly increases the migration and colony formation abilities of BEAS-2B cells, leading to cell malignant transformation. Notably, the malignant transformation of BEAS-2B cells is irreversible within 60 days recovery period after SWCNTs exposure, and the malignant transformation activities of cells gradually increase during the recovery period. Mechanism analyses show that post-chronic exposure to SWCNTs causes substantial DNA methylation and transcriptome dysregulation of BEAS-2B cells. Subsequent enrichment and clinical database analyses reveal that differentially expressed/methylated genes of BEAS-2B cells are enriched in cancer-related biological pathways, and several of these genes are validated in lung cancer patients.

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Benchmark Dose Modeling Approaches for Volatile Organic Chemicals using a Novel Air-Liquid Interface In Vitro Exposure System

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