Dopamine prevents ultraviolet B-induced development and progression of premalignant cutaneous lesions through its D2 receptors.

Although the role of dopamine (DA) in malignant tumors has been reported, its function in premalignant lesions is unknown. Herein we report that the stimulation of DA D2 receptors in endothelial cells in ultraviolet B (UVB)-induced cutaneous lesions in mice significantly reduced the tumor number, tumor burden, and malignant squamous cell carcinoma in these animals. DA D2 receptor agonist inhibited vascular-endothelial growth factor-A (VEGF)-dependent proangiogenic genes in vitro and in vivo. However, the mice pretreated with selective DA D2 receptor antagonist inhibited the actions of the agonist, thereby suggesting that the action of DA was through its D2 receptors in the endothelial cells. To our knowledge, this study is the first to report DA-mediated regulation of pathogenesis and progression of UVB-induced premalignant skin lesions.