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Background: Tobacco consumption in smoking and non‐smoking forms has been consequential in the rise of oral cancer cases. Among different forms, epidemiological studies from Middle Eastern countries and rural parts of northern India have reported increasing association of oral cancer with waterpipe (hookah) smoking. However, molecular mechanisms and role played by waterpipe smoking in the onset of oral carcinogenesis remains unexplored. Methods: In this study, immortalized normal human oral keratinocytes were chronically treated with extracts of two varieties of waterpipe tobacco—crude tobacco and processed shisha. Phenotypic changes and molecular aberrations were examined using cell culture‐based assays and mass spectrometry‐based quantitative proteomic analysis, respectively. Bioinformatics analysis was utilized to analyze proteomics data and identify dysregulated pathways. Results: Our data indicate that chronic treatment with waterpipe tobacco extracts increased proliferation, invasion, migration, and significant dysregulation of protein expression in oral keratinocytes. Altered expression of proteins involved in interferon signaling pathway were observed with both varieties of tobacco. Overexpression of cholesterol metabolism and vesicle‐mediated transport proteins were identified exclusively in cells treated with crude tobacco extract. Bioinformatics analyses revealed different oncogenic response in oral cells based on the type of waterpipe tobacco used. Conclusions: This study may serve as a useful resource in understanding the early onset of oral cancer attributed to waterpipe smoking. [ABSTRACT FROM AUTHOR]

Oral squamous cell carcinoma (OSCC) is known for its aggressiveness associated with poor prognosis. The molecular mechanisms underlying the invasion and metastasis are still poorly understood. An improved understanding of these mechanisms shall precede the development of new diagnostic tools and targeted therapies. We report an integrated approach using bioinformatics to predict candidate genes, coupled with proteomics and immunohistochemistry for validating their presence and involvement in OSCC pathways heralding invasion and metastasis. Four genes POSTN, TNC, CAV1 and FSCN1 were identified. A protein–protein interaction network analysis teamed with pathway analysis led us to propose the role of the identified genes in invasion and metastasis in OSCC. Further analyses of archived FFPE blocks of various grades of oral cancer was carried out using TMT-based mass spectrometry and immunohistochemistry. Results of this study expressed a strong communiqué and interrelationship between these candidate genes. This study emphasizes the significance of a molecular biomarker panel as a diagnostic tool and its correlation with the invasion and metastatic pathway of OSCC. An insight into the probable association of CAF's and these biomarkers in the evolution and malignant transformation of OSCC further magnifies the molecular-biological spectrum of OSCC tumour microenvironment. [ABSTRACT FROM AUTHOR]

BACKGROUND: Shisha smoking has been associated with multiple diseases including oral cancer. However, a mechanistic study to investigate alteration of secreted proteins in oral cells due to shisha smoking is lacking. OBJECTIVES: Elucidation of differentially secreted proteins by immortalized human normal oral keratinocytes (OKF6/TERT1) upon chronic exposure to shisha. METHODS: OKF6/TERT1 was chronically treated with 0.5% shisha extract for 8 months. Conditioned media from shisha treated (OKF6/TERT1-Shisha) and untreated (OKF6/TERT1-Parental) cells were subjected to TMT-based quantitative proteomic analysis. Bioinformatics analysis of differentially secreted proteins was carried out using SignalP, SecretomeP and TMHMM. Immunoblot validation of selected proteins was carried out to confirm the proteomics results. RESULTS: Proteomic analysis of OKF6/TERT1-Parental and OKF6/TERT1-Shisha secretome resulted in the identification of 1,598 proteins, of which 218 proteins were found to be differentially secreted (⩾ 1.5-fold; p -value ⩽ 0.05) in shisha treated cells. Bioinformatics analysis using prediction tools showed secretory potential of differentially secreted proteins identified in OKF6/TERT1-Shisha. Western blotting validated the expression of AKR1C2, HSPH1 and MMP9 in OKF6/TERT1-Shisha secretome in agreement with proteomic data. CONCLUSION: This study serves as a useful resource to understand the effect of chronic shisha smoking on the milieu of secreted proteins of oral cells. In vivo studies are warranted to supplement our in vitro data to elucidate the role of these proteins as early diagnostic biomarkers for oral carcinogenesis among shisha smokers. [ABSTRACT FROM AUTHOR]

Tobacco abuse is a major risk factor associated with the development of oral squamous cell carcinoma. Differences in molecular aberrations induced by tobacco exposure by chewing or smoking form are not well studied in case of oral cancer. We used tandem mass tag-based quantitative proteomic approach to delineate proteomic alterations in oral cancer patients based on their history of tobacco using habits (patients who chewed tobacco, patients who smoked tobacco, and those with no history of tobacco consumption). Our data identified distinct dysregulation of biological processes and pathways in each patient cohort. Bioinformatics analysis of dysregulated proteins identified in our proteomic study revealed dysregulation of collagen formation and antigen processing/presentation pathway in oral cancer patients who smoked tobacco, whereas proteins associated with the process of keratinization showed enrichment in patients who chewed tobacco. In addition, we identified overexpression of proteins involved in immune pathways and downregulation of muscle contraction-mediated signaling events in all three cohorts, irrespective of tobacco using habits. This study lays the groundwork for identification of protein markers that may aid in identification of high-risk patients for cancer development based on the history of tobacco exposure habits. [ABSTRACT FROM AUTHOR]

Proteins present in human saliva offer an immense potential for clinical applications. However, exploring salivary proteome is technically challenged due to the presence of amylase and albumin in high abundance. In this study, we used four workflows to analyze human saliva from healthy individuals which involved depletion of abundant proteins using affinity-based separation methods followed by protein or peptide fractionation and high resolution mass spectrometry analysis. We identified a total of 1256 human salivary proteins, 292 of them being reported for the first time. All identifications were verified for any shared proteins/peptides from the salivary microbiome that may conflict with the human protein identifications. On integration of our results with the analyses reported earlier, we arrived at an updated human salivary proteome containing 3449 proteins, 808 of them have been reported as differentially expressed proteins in oral cancer tissues. The secretory nature of 598 of the 808 proteins has also been supported on the basis of the presence of signal sequence, transmembrane domain or association with exosomes. From this subset, we provide a priority list of 139 proteins along with their proteotypic peptides, which may serve as a reference for targeted investigations as secretory markers for clinical applications in oral malignancies. This article is part of a Special Issue entitled: Proteomics in India. [ABSTRACT FROM AUTHOR]