Metabolites of PPI-2458, a Selective, Irreversible Inhibitor of Methionine Aminopeptidase-2: Structure Determination and In Vivo Activity
作者:Christopher C. Arico-Muendel、Bruce Belanger、Dennis Benjamin、Heather S. Blanchette、Teresa M. Caiazzo、Paolo A. Centrella、Jennifer DeLorey、Elisabeth G. Doyle、Ulrike Gradhand、Sarah T. Griffin、Susan Hill、Matthew T. Labenski、Barry A. Morgan、Gary O’Donovan、Kavirayani Prasad、Steven Skinner、Nazbeh Taghizadeh、Charles D. Thompson、James Wakefield、William Westlin、Kerry F. White
DOI:10.1124/dmd.112.048355
日期:2013.4
The natural product fumagillin exhibits potent antiproliferative and antiangiogenic properties. The semisynthetic analog PPI-2458, [(3R,4S,5S,6R)-5-methoxy-4-[(2R,3R)-2-methyl-3-(3-methylbut-2-enyl)oxiran-2-yl]-1-oxaspiro[2.5]octan-6-yl] N -[(2R)-1-amino-3-methyl-1-oxobutan-2-yl]carbamate, demonstrates rapid inactivation of its molecular target, methionine aminopeptidase-2 (MetAP2), and good efficacy in several rodent models of cancer and inflammation with oral dosing despite low apparent oral bioavailability. To probe the basis of its in vivo efficacy, the metabolism of PPI-2458 was studied in detail. Reaction phenotyping identified CYP3A4/5 as the major source of metabolism in humans. Six metabolites were isolated from liver microsomes and characterized by mass spectrometry and nuclear resonance spectroscopy, and their structures were confirmed by chemical synthesis. The synthetic metabolites showed correlated inhibition of MetAP2 enzymatic activity and vascular endothelial cell growth. In an ex vivo experiment, MetAP2 inhibition in white blood cells, thymus, and lymph nodes in rats after single dosing with PPI-2458 and the isolated metabolites was found to correlate with the in vitro activity of the individual species. In a phase 1 clinical study, PPI-2458 was administered to patients with non-Hodgkin lymphoma. At 15 mg administered orally every other day, MetAP2 in whole blood was 80% inactivated for up to 48 hours, although the exposure of the parent compound was only ∼ 10% that of the summed cytochrome P450 metabolites. Taken together, the data confirm the participation of active metabolites in the in vivo efficacy of PPI-2458. The structures define a metabolic pathway for PPI-2458 that is distinct from that of TNP-470 ([(3R,4S,5S,6R)-5-methoxy-4-[(2R,3R)-2-methyl-3-(3-methylbut-2-enyl)oxiran-2-yl]-1-oxaspiro[2.5]octan-6-yl] N -(2-chloroacetyl)carbamate). The high level of MetAP2 inhibition achieved in vivo supports the value of fumagillin-derived therapeutics for angiogenic diseases.
天然产物福马吉林具有强效的抗增殖和抗血管生成特性。The semisynthetic analog PPI-2458, [(3R,4S,5S,6R)-5-methoxy-4-[(2R,3R)-2-methyl-3-(3-methylbut-2-enyl)oxiran-2-yl]-1-oxaspiro[2.5]octan-6-yl]N -[(2R)-1-氨基-3-甲基-1-氧代丁-2-基]氨基甲酸酯可快速灭活其分子靶标蛋氨酸氨肽酶-2 (MetAP2),并且尽管口服生物利用度较低,但在多种癌症和炎症啮齿动物模型中口服具有良好疗效。为了探究其体内疗效的基础,我们对 PPI-2458 的代谢进行了详细研究。反应表型确定 CYP3A4/5 是人体代谢的主要来源。从肝脏微粒体中分离出了六种代谢物,并通过质谱和核共振光谱对其进行了表征,还通过化学合成确认了它们的结构。合成的代谢物对 MetAP2 酶活性和血管内皮细胞生长有相关的抑制作用。在一项体内外实验中,大鼠在单次服用 PPI-2458 和分离出的代谢物后,其白细胞、胸腺和淋巴结中的 MetAP2 抑制作用与单个物种的体外活性相关。在一项 1 期临床研究中,PPI-2458 被用于非霍奇金淋巴瘤患者。每隔一天口服 15 毫克,全血中 MetAP2 的灭活率为 80%,持续时间长达 48 小时,但母体化合物的暴露量仅为细胞色素 P450 代谢物总和的 10%。总之,这些数据证实了活性代谢物参与了 PPI-2458 的体内药效。这些结构确定了 PPI-2458 不同于 TNP-470 ([(3R,4S,5S,6R)-5-甲氧基-4-[(2R,3R)-2-甲基-3-(3-甲基丁-2-烯基)环氧乙烷-2-基]-1-氧杂螺[2.5]辛烷-6-基])的代谢途径。N-(2-氯乙酰基)氨基甲酸酯)。在体内实现的对 MetAP2 的高水平抑制支持了烟曲霉素衍生疗法治疗血管生成疾病的价值。