Guo Meng, Roman Richard J, Falck John R, Edwards Paul A, Scicli A Guillermo
Eye Care Services, Henry Ford Hospital, Detroit, MI 48202-3450, USA.
J Pharmacol Exp Ther. 2005 Nov;315(2):526-33. doi: 10.1124/jpet.105.088567. Epub 2005 Aug 4.
We have previously reported that HET0016 [N-hydroxy-N'-(4-butyl-2 methylphenyl)formamidine], a selective inhibitor of CYP4A and thus 20-HETE (20-hydroxyeicosatetraenoic acid) synthesis, inhibits endothelial cell proliferation and decreases angiogenesis induced by human glioma cell U251. A stable 20-HETE agonist, WIT003 [20-hydroxyeicosa-5(Z),14(Z)-dienoic acid (1 microM)], increased U251 cell proliferation from 3.9- to 4.8-folds from T(0) (time of the treatment). We examined the effects of HET0016 on the growth of U251. HET0016 inhibited U251 basal cell proliferation in a dose-dependent manner. 10 microM HET0016 suppressed 56% of U251 proliferation and significantly increased the proportions of the cells arrested in the G(0)/G(1) phase of the cell cycle. Exposure to HET0016 (as early as 4 h) reduced protein tyrosine and p42/p44 MAPK (mitogen-activated protein kinase) phosphorylation. Furthermore, HET0016 significantly inhibited the U251 proliferation and phosphorylation of both the epidermal growth factor (EGF) receptor and p42/p44 MAPK induced by EGF. CYP4A mRNA and proteins were both present in U251. This suggests that HET0016 inhibited U251 proliferation by inhibiting 20-HETE synthesis. However, U251 did not synthesize 20-HETE in the presence of arachidonic acid. This implies that HET0016 suppresses U251 proliferation by mechanisms that are not yet clear but may involve activities other than inhibition of 20-HETE synthesis. We concluded that HET0016 may be the prototype of novel compounds that suppress human glioma cell proliferation.
我们之前曾报道，HET0016 [N-羟基-N'-(4-丁基-2-甲基苯基)甲脒]，一种细胞色素P450 4A（CYP4A）的选择性抑制剂，因而也是20-羟基二十碳四烯酸（20-HETE）合成的抑制剂，可抑制内皮细胞增殖，并减少人胶质瘤细胞U251诱导的血管生成。一种稳定的20-HETE激动剂，WIT003 [20-羟基-5(Z),14(Z)-二十碳二烯酸（1微摩尔）]，使U251细胞增殖从处理时的T(0)起增加了3.9至4.8倍。我们研究了HET0016对U251生长的影响。HET0016以剂量依赖性方式抑制U251基础细胞增殖。10微摩尔的HET0016抑制了56%的U251增殖，并显著增加了停滞在细胞周期G(0)/G(1)期的细胞比例。暴露于HET0016（早在4小时）可降低蛋白质酪氨酸和p42/p44丝裂原活化蛋白激酶（MAPK）的磷酸化。此外，HET0016显著抑制表皮生长因子（EGF）受体和EGF诱导的p42/p44 MAPK的U251增殖和磷酸化。CYP4A mRNA和蛋白质在U251中均有表达。这表明HET0016通过抑制20-HETE合成来抑制U251增殖。然而，U251在花生四烯酸存在的情况下并不合成20-HETE。这意味着HET0016通过尚不清楚的机制抑制U251增殖，但可能涉及除抑制20-HETE合成之外的其他活性。我们得出结论，HET0016可能是抑制人胶质瘤细胞增殖的新型化合物的原型。
