Transcriptome changes induced in vitro by alcohol‐containing mouthwashes in normal and dysplastic oral keratinocytes

• Published in: Journal of oral pathology & medicine Vol. 47; no. 5; pp. 511 - 518
• Main Authors: Fox, Simon A., Currie, Sean S., Dalley, Andrew J., Farah, Camile S.
• Format: Journal Article
• Language: English
• Published: Denmark Wiley Subscription Services, Inc 01.05.2018
• Subjects: Alcohol; alcohol mouthwash; Alcohols - adverse effects; Bioinformatics; Carcinogens; Cell Line; Comet assay; DNA damage; DNA Damage - drug effects; dysplasia; Epidemiology; Ethanol; Ethanol - adverse effects; Gene expression; Gene Expression - drug effects; Genotoxicity; Humans; In Vitro Techniques; Inflammation; Inflammation - genetics; Keratinocytes; Keratinocytes - drug effects; Keratinocytes - metabolism; Mouth Mucosa - cytology; Mouth Mucosa - drug effects; Mouth Neoplasms - chemically induced; Mouth Neoplasms - genetics; Mouthwashes; Mouthwashes - adverse effects; Mouthwashes - chemistry; Oral cancer; Ribonucleic acid; Risk Factors; RNA; Signal transduction; transcriptome; Transcriptome - drug effects; dysplasia; genotoxicity; alcohol mouthwash; transcriptome; oral cancer
• ISSN: 0904-2512; 1600-0714; 1600-0714
• DOI: 10.1111/jop.12704

Background The role of alcohol‐containing mouthwash as a risk factor for the development of oral cancer is a subject of conflicting epidemiological evidence in the literature despite alcohol being a recognised carcinogen. The aim of this study was to use in vitro models to investigate mechanistic and global gene expression effects of exposure to alcohol‐containing mouthwash. Methods Two brands of alcohol‐containing mouthwash and their alcohol‐free counterparts were used to treat two oral cell lines derived from normal (OKF6‐TERT) and dysplastic (DOK) tissues. Genotoxicity was determined by Comet assay. RNA‐seq was performed using the Ion Torrent platform. Bioinformatics analysis used R/Bioconductor packages with differential expression using DEseq2. Pathway enrichment analysis used EnrichR with the WikiPathways and Kegg databases. Results Both cell lines displayed dose‐dependent DNA damage in response to acute exposure to ethanol and alcohol‐containing mouthwashes as well as alcohol‐free mouthwashes reconstituted with ethanol as shown by Comet assay. The transcriptomic effects of alcohol‐containing mouthwash exposure were more complex with significant differential gene expression ranging from >2000 genes in dysplastic (DOK) cells to <100 genes in normal (OKF6‐TERT) cells. Pathway enrichment analysis in DOK cells revealed alcohol‐containing mouthwashes showed common features between the two brands used including DNA damage response as well as cancer‐associated pathways. In OKF6‐TERT cells, the most significantly enriched pathways involved inflammatory signalling. Conclusions Alcohol‐containing mouthwashes are genotoxic in vitro to normal and dysplastic oral keratinocytes and induce widespread changes in gene expression. Dysplastic cells are more susceptible to the transcriptomic effects of mouthwash.