Molecular alterations associated with chronic exposure to cigarette smoke and chewing tobacco in normal oral keratinocytes

Abstract

Tobacco usage is a known risk factor associated with development of oral cancer. It is mainly consumed in two different forms (smoking and chewing) that vary in their composition and methods of intake. Despite being the leading cause of oral cancer, molecular alterations induced by tobacco are poorly understood. We therefore sought to investigate the adverse effects of cigarette smoke/chewing tobacco exposure in oral keratinocytes (OKF6/TERT1). OKF6/TERT1 cells acquired oncogenic phenotype after treating with cigarette smoke/chewing tobacco for a period of 8 months. We employed whole exome sequencing (WES) and quantitative proteomics to investigate the molecular alterations in oral keratinocytes chronically exposed to smoke/ chewing tobacco. Exome sequencing revealed distinct mutational spectrum and copy number alterations in smoke/ chewing tobacco treated cells. We also observed differences in proteomic alterations. Proteins downstream of MAPK1 and EGFR were dysregulated in smoke and chewing tobacco exposed cells, respectively. This study can serve as a reference for fundamental damages on oral cells as a consequence of exposure to different forms of tobacco.

Multiomic analysis of oral keratinocytes chronically exposed to shisha

“…30 We have previously observed marked overexpression and activation of MAPK1 in OKF6/ TERT1 cells chronically exposed to cigarette smoke. 12 Despite distinct genomic anomalies in OKF6/TERT1 cells chronically treated with cigarette smoke and shisha extract, interferon-signaling cascade was a commonly affected pathway in both models.…”

“…Previous study by our group elucidated the molecular alterations in oral cells upon chronic cigarette smoke exposure. 12 In that study, OKF6/TERT1-Parental cells were chronically treated with cigarette C>T transversions is known to be associated with various cancers. 21 We did not observe any commonalities among genomic anomalies, however, pathway analysis using IPA predicted activation of mitogen-activated protein kinase 1 (MAPK1) pathway (z-score ≥ 2) ( Figure 2B).…”

“…We developed a cell line model using immortalized normal oral keratinocytes by chronically treating them with shisha extract for a period of 8 months. We have previously investigated cellular models using cigarette smoke and chewing tobacco to understand molecular alterations associated with different forms of tobacco …”

“…We have previously investigated cellular models using cigarette smoke and chewing tobacco to understand molecular alterations associated with different forms of tobacco. 12,13 In this study, we investigated mutational spectrum and dysregulation of gene expression pattern in immortalized normal human oral keratinocytes (OKF6/TERT1) chronically treated with shisha extract.…”

Multi-Omics Analysis to Characterize Cigarette Smoke Induced Molecular Alterations in Esophageal Cells

“…However, molecular alterations associated with cigarette smoke exposure in esophageal cells remains poorly understood. We and others have shown that in vitro cell models with chronic cigarette smoke extract/condensate are helpful in understanding oncogenic transformation of non-neoplastic esophageal cells (41), lung epithelial type-II cells (42), urothelial cells (43), breast epithelial cells (44), and oral cells (45,46). Cigarette smoke contains more than 70 carcinogenic compounds that are responsible for development of cancer.…”