Identification of tumor promoter of UV-carcinogenesis of the skin and the suppression of carcinogenesis by inhibiting tumor promoter

点击翻译按钮获取中文摘要

(1)Cyclooxygenase-2 (COX-2) has been shown to be activated by UV and has been suggested to act as a tumor promotor. We examined the mechanism of COX-2 activation by UVB in HaCaT keratinocytes and found that oxygen radicals and activation of EGF-receptor are involved in this event. (2)To reveal that oxidized diacylglycerol acts as tumor promotor of UV-carcinogenesis, oxidized diacylglycerol was applied to the mouse skin after the initiation with DMBA. However, we could not observe the tumor formation. (3)Telomerase activation is the critical step for carcinogenesis and the inhibition of telomerase may lead to suppression of carcinogenesis. The mechanism of telomerase activation in squamous cell carcinome cells was examined and we found that the EGF-receptor activity is important for the telomerase activity. (3)Induction of apoptosis is crucial for the treatment of cancer. Genistein, an isoflavon in soy beans, was examined whether it augments apoptosis in melanoma cells by cisplatinum. Treatment with genistein and cisplatinum increased apoptosis in association with the decreased expression of bcl-2 and bcl-xL and increased expression of Apaf-1.