Norepinephrine upregulates VEGF, IL-8, and IL-6 expression in human melanoma tumor cell lines: Implications for stress-related enhancement of tumor progression

Studies suggest that stress can be a co-factor for the initiation and progression of cancer. The catecholamine stress hormone, norepinephrine (NE), may influence tumor progression by modulating the expression of factors implicated in angiogenesis and metastasis. The goal of this study was to examine the influence of NE on the expression of VEGF, IL-8, and IL-6 by the human melanoma cell lines, C8161, 1174MEL, and Me 18105. Cells were treated with NE and levels of VEGF, IL-8, and IL-6 were measured using ELISA and real-time PCR. The expression of beta-adrenergic receptors (beta-ARs) mRNA and protein were also assessed. Finally, immunohistochemistry was utilized to examine the presence of beta 1- and beta 2-AR in primary and metastatic human melanoma biopsies. We show that NE treatment upregulated production of VEGF, IL-8, and IL-6 in C8161 cells and to a lesser extent 1174MEL and Me18105 cells. The upregulation was associated with induced gene expression. The effect on C8161 cells was mediated by both beta 1- and beta 2-ARs. Furthermore, 18 of 20 melanoma biopsies examined expressed beta 2-AR while 14 of 20 melanoma biopsies expressed beta 1-AR. Our data support the hypothesis that NE can stimulate the aggressive potential of melanoma tumor cells, in part, by inducing the production VEGF, IL-8, and IL-6. This line of research further suggests that interventions targeting components of the activated sympathetic-ad renal medullary (SAM) axis, or the utilization of beta-AR blocking agents, may represent new strategies for slowing down the progression of malignant disease and improving cancer patients' quality of life. (C) 2008 Elsevier Inc. All rights reserved.