Jiang Jian-Gang, Chen Chun-Lian, Card Jeffrey W, Yang Shilin, Chen Ji-Xiong, Fu Xiang-Ning, Ning Yao-Gui, Xiao Xiao, Zeldin Darryl C, Wang Dao Wen
Department of Internal Medicine and Gene Therapy Center, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, PR China.
Cancer Res. 2005 Jun 1;65(11):4707-15. doi: 10.1158/0008-5472.CAN-04-4173.
Cytochrome P450 (CYP) arachidonic acid epoxygenase 2J2 converts arachidonic acid to four regioisomeric epoxyeicosatrienoic acids, which exert diverse biological activities in cardiovascular system and endothelial cells. However, it is unknown whether this enzyme highly expresses and plays any role in cancer. In this study, we found that very strong and selective CYP2J2 expression was detected in human carcinoma tissues in 101 of 130 patients (77%) as well as eight human carcinoma cell lines but undetectable in adjacent normal tissues and nontumoric human cell lines by Western, reverse transcription-PCR, and immunohistochemical staining. In addition, forced overexpression of CYP2J2, and CYP BM3F87V or addition of epoxyeicosatrienoic acids (EET) in cultured carcinoma cell lines in vitro markedly accelerated proliferation by analyses of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, cell accounts, and cell cycle analysis, and protected carcinoma cells from apoptosis induced by tumor necrosis factor alpha (TNF-alpha) in cultures. In contrast, antisense 2J2 transfection or addition of epoxygenase inhibitors 17-ODYA inhibited proliferation and accelerated cell apoptosis induced by TNF-alpha. Examination of signaling pathways on the effects of CYP2J2 and EETs revealed activation of mitogen-activated protein kinases and PI3 kinase-AKT systems and elevation of epithelial growth factor receptor phosphorylation level. These results strongly suggest that CYP epoxygenase 2J2 plays a previously unknown role in promotion of the neoplastic cellular phenotype and in the pathogenesis of a variety of human cancers.
细胞色素P450（CYP）花生四烯酸环氧化酶2J2可将花生四烯酸转化为四种区域异构体环氧二十碳三烯酸，这些环氧二十碳三烯酸在心血管系统和内皮细胞中发挥多种生物学活性。然而，该酶是否在癌症中高表达并发挥作用尚不清楚。在本研究中，我们发现，通过蛋白质免疫印迹法、逆转录PCR和免疫组织化学染色，在130例患者中的101例（77%）的人类癌组织以及8种人类癌细胞系中检测到非常强且选择性的CYP2J2表达，但在相邻正常组织和非肿瘤人类细胞系中未检测到。此外，通过3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐分析、细胞计数和细胞周期分析，在体外培养的癌细胞系中强制过表达CYP2J2和CYP BM3F87V或添加环氧二十碳三烯酸（EET）可显著加速细胞增殖，并保护癌细胞免受肿瘤坏死因子α（TNF-α）诱导的凋亡。相反，反义2J2转染或添加环氧酶抑制剂17-ODYA可抑制增殖并加速TNF-α诱导的细胞凋亡。对CYP2J2和EETs作用的信号通路研究显示，丝裂原活化蛋白激酶和PI3激酶-AKT系统被激活，上皮生长因子受体磷酸化水平升高。这些结果强烈表明，CYP环氧化酶2J2在促进肿瘤细胞表型及多种人类癌症的发病机制中发挥了前所未知的作用。
