Effects of chronic exposure to norepinephrine and tobacco-derived carcinogen NNK on the malignant phenotypic characteristics in human oral keratinocytes

Abstract

Recent evidence shows that stress-related hormone norepinephrine may influence cancer progression. However, the effects of norepinephrine on cancer onset are poorly known. Chronic tobacco use is the main risk factor for oral cancer development. The carcinogen derived from tobacco 4 (N-methyl-nitrosamino)-1-(3-pyridyl) butan-1-one) (NNK) can induce oral carcinogenesis. There are no studies that have evaluated the effects of chronic exposure to norepinephrine and NNK on the malignant transformation of oral keratinocytes. This project aim to investigate the effects of norepinephrine and NNK on the induction of malignant phenotypic characteristics in human normal oral keratinocytes. These cells will be exposed to norepinephrine (10 uM) in the presence or absence of NNK (10 uM). Non-exposed cells will be used as control. After a 30-day exposure period to norepinephrine and/or NNK, the morphological characteristics of malignancy found in the epithelial cells will be evaluated using the cytological technique. Malignant cell transformation will be assessed by the soft agar colony formation assay. In addition, cell proliferation and migration will also be evaluated after exposure to norepinephrine and/or NNK. Statistical tests will be used to determine possible differences between the groups treated with norepinephrine in the presence or absence of NNK.