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Smokeless tobacco increases aneuploidy in oral HPV 16 E6/E7‐transformed keratinocytes in vitro
Author(s) -
Merne Marina,
Rautava Jaana,
Ruutu Merja,
Syrjänen Stina
Publication year - 2014
Publication title -
journal of oral pathology and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 83
eISSN - 1600-0714
pISSN - 0904-2512
DOI - 10.1111/jop.12185
Subject(s) - keratinocyte , flow cytometry , smokeless tobacco , aneuploidy , in vitro , biology , snuff , cell culture , andrology , immunology , medicine , cancer research , microbiology and biotechnology , pathology , gene , population , genetics , environmental health , tobacco use , chromosome
Background The scope of this work was to study synergism between human papillomavirus ( HPV ) infection and tobacco in vitro , both known to be independent risk factors for oral cancer. Methods HPV‐positive and HPV‐negative oral keratinocytes and oral HPV ‐negative fibroblasts were exposed to smokeless tobacco extract ( STE ) prepared from the S candinavian ( STE 1) and US‐type ( STE 2) snuff. Cell cycle profiles were determined with flow cytometry, and HPV E6/E7 mRNA expression in HPV‐positive cells was assayed using RT‐ qPCR . Results The exposure of HPV ‐positive keratinocytes with STE 2 increased the number of aneuploid cells from 27% to 80% of which 44% were in S‐phase, while none of the diploid cells were in S‐phase. The changes after STE 1 exposure were less than seen after STE 2: from 27% to 31% of which 34% were in S‐phase. STE had no effect on HPV 16 E6/E7 expression in HPV ‐positive keratinocytes. In oral spontaneously transformed, HPV ‐negative keratinocytes, the number of aneuploid cells at G2‐M stage increased after STE 1 and STE 2 exposure from 3% to 9% and 7%, respectively. In HPV ‐negative oral fibroblasts, the number of cells at G2‐M phase increased from 11% to 21% after STE 1 and 29% after STE 2 exposure. Conclusions The effect of STE varied in the cell lines studied. STE 2 increased significantly the proportion of aneuploid cells in HPV ‐positive oral keratinocytes, but not HPV 16 E6/E7 expression. This indicates that tobacco products may enhance the effects of HPV 16 and the risk of DNA aneuploidy increasing risk to malignant transformation.