Huber Eva M, Heinemeyer Wolfgang, Groll Michael
Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany.
Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany.
Structure. 2015 Feb 3;23(2):407-17. doi: 10.1016/j.str.2014.11.019. Epub 2015 Jan 15.
Inhibition of the 20S proteasome by bortezomib (Velcade) constitutes a successfully applied therapy for blood cancer. However, emerging resistance restricts its medicinal use. For example, mutations in the proteolytically active β5-subunit of the proteasome, the main target of inhibitors, were reported to impair drug binding and thus to reduce therapeutic efficacy. Using yeast as a model system, we describe here a systematic evaluation of these mutations by cell growth analysis, proteasome inhibition assays, and X-ray crystallography. The 11 mutants examined display decreased proliferation rates, impaired proteolytic activity, and marked resistance to bortezomib as well as the α',β'-epoxyketone inhibitors carfilzomib (Kyprolis) and ONX 0914, while the second-generation compound carfilzomib was the least affected. In total, 49 proteasome X-ray structures, including structural data on proteasome-carfilzomib complexes, reveal three distinct molecular mechanisms that hamper both drug binding and natural substrate turnover to an extent that is still compatible with cell survival.
硼替佐米（万珂）对20S蛋白酶体的抑制作用构成了一种成功应用于血癌治疗的方法。然而，新出现的耐药性限制了其药用价值。例如，据报道，蛋白酶体的蛋白水解活性β5亚基（抑制剂的主要靶点）发生突变会损害药物结合，从而降低治疗效果。我们以酵母作为模型系统，在此通过细胞生长分析、蛋白酶体抑制试验和X射线晶体学对这些突变进行了系统评估。所检测的11个突变体显示出增殖速率降低、蛋白水解活性受损，对硼替佐米以及α',β'-环氧酮抑制剂卡非佐米（凯洛斯）和ONX 0914具有显著抗性，而第二代化合物卡非佐米受影响最小。总共49个蛋白酶体X射线结构，包括蛋白酶体 - 卡非佐米复合物的结构数据，揭示了三种不同的分子机制，这些机制在一定程度上阻碍了药物结合和天然底物周转，但仍与细胞存活相容。
