Perchellet Jean-Pierre H, Perchellet Elisabeth M, Crow Kyle R, Buszek Keith R, Brown Neil, Ellappan Sampathkumar, Gao Ge, Luo Diheng, Minatoya Machiko, Lushington Gerald H
Anti-Cancer Drug Laboratory, Kansas State University, Division of Biology, Ackert Hall, Manhattan, KS 66506-4901, USA.
Int J Mol Med. 2009 Nov;24(5):633-43. doi: 10.3892/ijmm_00000274.
Pilot-scale libraries of eight-membered medium ring lactams (MRLs) and related tricyclic compounds (either seven-membered lactams, thiolactams or amines) were screened for their ability to inhibit the catalytic activity of human recombinant 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase in vitro. A dozen of the synthetic compounds mimic the inhibition of purified HMG-CoA reductase activity caused by pravastatin, fluvastatin and sodium salts of lovastatin, mevastatin and simvastatin in this cell-free assay, suggesting direct interaction with the rate-limiting enzyme of cholesterol biosynthesis. Moreover, several MRLs inhibit the metabolic activity of L1210 tumor cells in vitro to a greater degree than fluvastatin, lovastatin, mevastatin and simvastatin, whereas pravastatin is inactive. Although the correlation between the concentration-dependent inhibitions of HMG-CoA reductase activity over 10 min in the cell-free assay and L1210 tumor cell proliferation over 4 days in culture is unclear, some bioactive MRLs elicit interesting combinations of statin-like (IC50: 7.4-8.0 microM) and anti-tumor (IC50: 1.4-2.3 microM) activities. The HMG-CoA reductase-inhibiting activities of pravastatin and an MRL persist in the presence of increasing concentrations of NADPH. But increasing concentrations of HMG-CoA block the HMG-CoA reductase-inhibiting activity of pravastatin without altering that of an MRL, suggesting that MRLs and existing statins may have different mechanisms of enzyme interaction and inhibition. When tested together, suboptimal concentrations of synthetic MRLs and existing statins have additive inhibitory effects on HMG-CoA reductase activity. Preliminary molecular docking studies with MRL-based inhibitors indicate that these ligands fit sterically well into the HMG-CoA reductase statin-binding receptor model and, in contrast to mevastatin, may occupy a narrow channel housing the pyridinium moiety on NADP+.
对八元中环内酰胺（MRLs）及相关三环化合物（七元内酰胺、硫代内酰胺或胺）的中试规模文库进行了筛选，以考察其在体外抑制人重组3-羟基-3-甲基戊二酰辅酶A（HMG-CoA）还原酶催化活性的能力。在这种无细胞测定中，有十几种合成化合物模拟了普伐他汀、氟伐他汀以及洛伐他汀、美伐他汀和辛伐他汀钠盐对纯化的HMG-CoA还原酶活性的抑制作用，这表明它们与胆固醇生物合成的限速酶存在直接相互作用。此外，几种MRLs在体外对L1210肿瘤细胞代谢活性的抑制程度比氟伐他汀、洛伐他汀、美伐他汀和辛伐他汀更大，而普伐他汀则无活性。尽管在无细胞测定中10分钟内HMG-CoA还原酶活性的浓度依赖性抑制与培养4天内L1210肿瘤细胞增殖之间的相关性尚不清楚，但一些具有生物活性的MRLs引发了他汀样（IC50：7.4 - 8.0 microM）和抗肿瘤（IC50：1.4 - 2.3 microM）活性的有趣组合。普伐他汀和一种MRL的HMG-CoA还原酶抑制活性在NADPH浓度增加时仍然存在。但是HMG-CoA浓度的增加会阻断普伐他汀的HMG-CoA还原酶抑制活性，而不会改变MRL的活性，这表明MRLs与现有他汀类药物可能具有不同的酶相互作用和抑制机制。当一起测试时，合成MRLs和现有他汀类药物的次优浓度对HMG-CoA还原酶活性具有相加抑制作用。基于MRL的抑制剂的初步分子对接研究表明，这些配体在空间上与HMG-CoA还原酶他汀结合受体模型匹配良好，并且与美伐他汀不同，可能占据了容纳NADP + 上吡啶鎓部分的狭窄通道。
