Marull Marc, Rochat Bertrand
Quantitative Mass Spectrometry Facility, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland.
J Mass Spectrom. 2006 Mar;41(3):390-404. doi: 10.1002/jms.1002.
Imatinib (Gleevec) is an anticancer drug that inhibits specific protein kinases involved in cell proliferation. Whereas this drug is considered to have opened a new era, various mechanisms of resistance have been associated with imatinib relapse. Drug disposition in cancer cells including influx, efflux and drug metabolism is one mechanism that remains to be more thoroughly investigated. Moreover, recent genomic studies have revealed that some isozymes of cytochrome P450 (CYP) are possibly associated with the treatment outcome. Therefore, this research paper investigates the role of the activity of CYP1A1, 1A2, 1B1, 3A4, 4F2 and 4F3A/B on the fate of imatinib. First, a study of imatinib fragmentation was effected using electrospray triple-quadrupole and linear ion trap tandem mass spectrometers (MSn). Accurate mass determinations were performed at enhanced mass resolution for the identification of some product ions that were not predicted by two fragmentation softwares. Whereas the quadrupole MS was not designed for accurate mass measurement, delta mass errors were below 20 ppm. Then, a biotransformation study was effected in vitro. Imatinib metabolites were produced in microsomal incubations containing CYP isozymes. Imatinib and metabolites were extracted from incubation mixtures by protein precipitation, and supernatants were injected into a liquid chromatography equipment coupled with MS(n). Hydrophobic interaction liquid chromatography resolved one demethylated-, two hydroxy- and three N-oxide metabolites. Various rates of metabolite formation were observed between CYP isozymes. Liquid chromatography with deuterium oxide-containing mobile phase (H/D exchange) or incorporation of (18)O from H(2) (18)O added in the incubations was performed to elucidate the metabolite structure. Various MS(n) product scans (n < or = 4) were acquired on the linear ion trap or on the triple-quadrupole MS. Postulated structures of new metabolites are addressed.
伊马替尼（格列卫）是一种抗癌药物，可抑制参与细胞增殖的特定蛋白激酶。尽管这种药物被认为开创了一个新时代，但与伊马替尼复发相关的耐药机制多种多样。癌细胞中的药物处置，包括药物流入、流出和药物代谢，是一个仍有待更深入研究的机制。此外，最近的基因组研究表明，细胞色素P450（CYP）的一些同工酶可能与治疗结果有关。因此，本研究论文探讨了CYP1A1、1A2、1B1、3A4、4F2和4F3A/B的活性对伊马替尼转归的作用。首先，使用电喷雾三重四极杆和线性离子阱串联质谱仪（MSn）对伊马替尼的碎片化进行了研究。在提高质量分辨率的情况下进行了精确质量测定，以鉴定两种碎片化软件未预测到的一些产物离子。尽管四极杆质谱仪并非设计用于精确质量测量，但质量偏差低于20 ppm。然后，进行了体外生物转化研究。在含有CYP同工酶的微粒体孵育中产生了伊马替尼代谢物。通过蛋白质沉淀从孵育混合物中提取伊马替尼及其代谢物，并将上清液注入与MS(n)联用的液相色谱设备中。疏水相互作用液相色谱分离出一种去甲基化代谢物、两种羟基代谢物和三种N - 氧化物代谢物。在CYP同工酶之间观察到了不同的代谢物形成速率。使用含氧化氘的流动相（H/D交换）或在孵育中加入H₂¹⁸O引入¹⁸O进行液相色谱分析，以阐明代谢物结构。在线性离子阱或三重四极杆质谱仪上进行了各种MS(n)产物扫描（n≤4）。讨论了新代谢物的假定结构。
