Hwang Mun Kyung, Kang Nam Joo, Heo Yong-Seok, Lee Ki Won, Lee Hyong Joo
Department of Agricultural Biotechnology, Seoul National University, Republic of Korea.
Biochem Pharmacol. 2009 Apr 1;77(7):1213-22. doi: 10.1016/j.bcp.2008.12.021. Epub 2009 Jan 7.
Tumor necrosis factor (TNF)-alpha-mediated cyclooxygenase (COX)-2 expression plays key roles in inflammation and tumorigenesis, particularly skin carcinogenesis, and hence targeting the TNF-alpha-mediated signaling pathway might be a promising strategy for developing chemopreventive agents against skin cancer and other skin disorders. Here we report that Fyn kinase - one of the members of the nonreceptor protein tyrosine kinase family - is involved in TNF-alpha-induced COX-2 expression, and that delphinidin - a major anthocyanidin present in red wine and berries - inhibits these effects by directly inhibiting Fyn kinase activity. Delphinidin strongly inhibited TNF-alpha-induced COX-2 expression in JB6 P+ mouse epidermal (JB6 P+) cells, whereas two other major phenolic compounds (resveratrol and gallic acid) did not exert significant inhibitory effects. Delphinidin inhibited the TNF-alpha-induced phosphorylations of JNK, p38 MAP kinase, Akt, p90RSK, MSK1, and ERK, and subsequently blocked the activation of the eukaryotic transcription factors AP-1 and NF-kappaB. Kinase and pull-down assay data revealed that delphinidin inhibited Fyn kinase activity and directly bound with Fyn kinase noncompetitively with ATP. By using PP2 (a commercial inhibitor of Fyn kinase) and siRNA-Fyn, we confirmed that Fyn kinase is involved in TNF-alpha-induced COX-2 expression mainly by down-regulating JNK in JB6 P+ cells. Together these findings suggest that the targeted inhibition of Fyn kinase activity and COX-2 expression by delphinidin contributes to the chemopreventive potential of red wine and berries.
肿瘤坏死因子（TNF）-α介导的环氧化酶（COX）-2表达在炎症和肿瘤发生过程中发挥关键作用，尤其是在皮肤癌发生过程中。因此，靶向TNF-α介导的信号通路可能是开发针对皮肤癌和其他皮肤疾病的化学预防剂的一种有前景的策略。在此，我们报告Fyn激酶（非受体蛋白酪氨酸激酶家族成员之一）参与TNF-α诱导的COX-2表达，并且飞燕草素（一种存在于红酒和浆果中的主要花青素）通过直接抑制Fyn激酶活性来抑制这些作用。飞燕草素强烈抑制TNF-α诱导的JB6 P+小鼠表皮细胞（JB6 P+）中COX-2的表达，而其他两种主要酚类化合物（白藜芦醇和没食子酸）未发挥显著抑制作用。飞燕草素抑制TNF-α诱导的JNK、p38丝裂原活化蛋白激酶、Akt、p90核糖体S6激酶、丝裂原和应激激活蛋白激酶1及细胞外信号调节激酶的磷酸化，随后阻断真核转录因子AP-1和核因子κB的激活。激酶和下拉分析数据表明，飞燕草素抑制Fyn激酶活性并与Fyn激酶直接结合，且与ATP无竞争性。通过使用PP2（Fyn激酶的商业抑制剂）和siRNA-Fyn，我们证实Fyn激酶在JB6 P+细胞中主要通过下调JNK参与TNF-α诱导的COX-2表达。这些发现共同表明，飞燕草素对Fyn激酶活性和COX-2表达的靶向抑制有助于红酒和浆果的化学预防潜力。
