Yonemoto M, Satoh T, Arakawa H, Suzuki-Takahashi I, Monden Y, Kodera T, Tanaka K, Aoyama T, Iwasawa Y, Kamei T, Nishimura S, Tomimoto K
Tsukuba Research Institute, Banyu Pharmaceutical, Ltd., Tsukuba, 300-2611 Japan.
Mol Pharmacol. 1998 Jul;54(1):1-7. doi: 10.1124/mol.54.1.1.
Farnesylation of the activated ras oncogene product by protein farnesyltransferase (FTase) is a critical step for its oncogenic function. Because squalene synthase and FTase recruit farnesyl pyrophosphate as a common substrate, we modified squalene synthase (SS) inhibitors to develop FTase inhibitors. Among the compounds tested, a novel FTase inhibitor termed J-104,871 inhibited rat brain FTase with an IC50 of 3.9 nM in the presence of 0.6 microM farnesyl pyrophosphate (FPP), whereas it scarcely inhibited rat brain protein geranylgeranyltransferase-I or SS. The in vitro inhibition of rat brain FTase by J-104,871 depends on the FPP concentration but not on the concentration of Ras peptide. Thus, in vitro studies strongly suggest that J-series compounds have an FPP-competitive nature. J-104,871 also inhibited Ras processing in activated H-ras-transformed NIH3T3 cells with an IC50 value of 3.1 microM. We tested the effects of lovastatin and zaragozic acid A, which modify cellular FPP levels, on Ras processing of J-104,871. Lovastatin, a hepatic hydroxymenthyl coenzyme A reductase inhibitor that reduced the cellular FPP pool, increased the activity of J-104,871, whereas 3 microM zaragozic acid A, an SS inhibitor that raised the FPP level, completely abrogated the activity of J-104,871 even at 100 microM. These results suggest that J-104,871 inhibits FTase in an FPP-competitive manner in whole cells as well as in the in vitro system. Furthermore, J-104,871 suppressed tumor growth in nude mice transplanted with activated H-ras-transformed NIH3T3 cells.
蛋白法尼基转移酶（FTase）对活化的ras癌基因产物进行法尼基化是其致癌功能的关键步骤。由于鲨烯合酶和FTase都将法尼基焦磷酸作为共同底物，我们对鲨烯合酶（SS）抑制剂进行改造以开发FTase抑制剂。在所测试的化合物中，一种名为J - 104,871的新型FTase抑制剂在存在0.6微摩尔法尼基焦磷酸（FPP）的情况下，以3.9纳摩尔的IC50抑制大鼠脑FTase，而它几乎不抑制大鼠脑蛋白香叶基香叶基转移酶-I或SS。J - 104,871对大鼠脑FTase的体外抑制作用取决于FPP浓度，而不取决于Ras肽的浓度。因此，体外研究强烈表明J系列化合物具有FPP竞争性。J - 104,871还以3.1微摩尔的IC50值抑制活化的H - ras转化的NIH3T3细胞中的Ras加工。我们测试了调节细胞FPP水平的洛伐他汀和扎戈司酸A对J - 104,871的Ras加工的影响。洛伐他汀是一种降低细胞FPP库的肝羟甲基辅酶A还原酶抑制剂，它增强了J - 104,871的活性，而3微摩尔的扎戈司酸A是一种提高FPP水平的SS抑制剂，即使在100微摩尔时也完全消除了J - 104,871的活性。这些结果表明J - 104,871在全细胞以及体外系统中以FPP竞争性方式抑制FTase。此外，J - 104,871抑制了移植有活化的H - ras转化的NIH3T3细胞的裸鼠中的肿瘤生长。
