Tranexamic Acid Ameliorates Nonmelanoma Skin Cancer Induced by Long-term Ultraviolet A Irradiation.

To date, there have been no treatments developed to ameliorate nonmelanoma skin cancer induced by long-term exposure to ultraviolet A (UVA) irradiation. In this study, we examined the effects of tranexamic acid (trans-4-aminomethyl cyclohexanecarboxylic acid) on long-term UVA-induced skin cancer. We exposed the dorsal skin of male hairless mice to UVA at a dose of 110 kJ m-2 using an FL20SBLB-A lamp three times weekly for 15 weeks after application of 7,12-dimethylbenz [a] anthracene (DMBA). During the experimental period, the mice were administered tranexamic acid (750 mg kg-1 day-1 ) three times weekly. We found that cancer development was ameliorated by administration of tranexamic acid. Furthermore, tranexamic acid treatment was observed to suppress increases in the plasma levels of matrix metalloproteinase-9 and interleukin (IL)-6, and skin expression of plasmin, CC chemokine 2, macrophages, signal transducer and activator of transcription (STAT)3, cyclin D and vascular endothelial growth factor (VEGF)-A that occurred in mice subjected to long-term UVA irradiation. These results indicated that the nonmelanoma skin cancer induced by DMBA+UVA long-term irradiation is ameliorated by tranexamic acid through regulation of the plasmin/macrophage/IL-6/STAT3/cyclin D signal transmission pathway. In addition, this ameliorative effect against skin cancer may be mediated via inhibition of the IL-6-induced expression of VEGF-A.