Department of Rheumatology, VU Institute for Cancer and Immunology, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
J Pharmacol Exp Ther. 2012 Apr;341(1):174-82. doi: 10.1124/jpet.111.187542. Epub 2012 Jan 10.
Bortezomib (BTZ), a registered proteasome inhibitor (PI) for multiple myeloma, has also been proposed as a potential antirheumatic agent. Its reported side effects, however, make it unappealing for long-term administration, and resistance may also develop. To overcome this, second-generation PIs became available. Here, we investigated whether a novel class of peptide epoxyketone-based PIs, including carfilzomib, N-((S)-3-methoxy-1-(((S)-3-methoxy-1-(((S)-1-((R)-2-methyloxiran-2-yl)-1-oxo-3-phenylpropan-2-yl)amino)-1-oxopropan-2-yl)amino)-1-oxopropan-2-yl)-2-methylthiazole-5-carboxamide (ONX0912), and (S)-3-(4-methoxyphenyl)-N-((S)-1-((S)-2-methyloxiran-2-yl)-1-oxo-3-phenylpropan-2-yl)-2-((S)-2-(2-morpholinoacetamido)propanamido)propanamide (ONX0914), might escape two established BTZ-resistance mechanisms: 1) mutations in the proteasome β5 subunit (PSMB5) targeted by these PIs, and 2) drug efflux mediated by ATP-binding cassette transporters. THP1 myeloid sublines with acquired resistance to BTZ (54- to 235-fold) caused by mutations in the PSMB5 gene displayed marked cross-resistance but less pronounced cross-resistance to carfilzomib (9- to 32-fold), ONX0912 (39- to 62-fold), and ONX0914 (27- to 97-fold). As for ATP-binding cassette transporter-mediated efflux, lymphoid CEM/VLB cells with P-glycoprotein (Pgp)/multidrug resistance 1 overexpression exhibited substantial resistance to carfilzomib (114-fold), ONX0912 (23-fold), and ONX0914 (162-fold), whereas less resistance to BTZ (4.5-fold) was observed. Consistently, β5 subunit-associated chymotrypsin-like proteasome activity was significantly less inhibited in these CEM/VLB cells. Ex vivo analysis of peripheral blood mononuclear cells from therapy-naive patients with rheumatoid arthritis revealed that, although basal Pgp levels were low, P-glycoprotein expression compromised the inhibitory effect of carfilzomib and ONX0914. However, the use of P121 (reversin 121), a Pgp transport inhibitor, restored parental cell inhibitory levels in both CEM/VLB cells and peripheral blood mononuclear cells. These results indicate that the pharmacologic activity of these PIs may be hindered by drug resistance mechanisms involving PSMB5 mutations and PI extrusion via Pgp.
硼替佐米（BTZ）是一种已注册的多发性骨髓瘤蛋白酶体抑制剂（PI），也被提议作为一种潜在的抗风湿药物。然而，其报道的副作用使其不适合长期给药，并且可能会产生耐药性。为了克服这一问题，第二代 PI 应运而生。在这里，我们研究了一类新型肽环氧酮类 PI，包括卡非佐米、N-((S)-3-甲氧基-1-(((S)-3-甲氧基-1-(((S)-1-((R)-2-环氧乙烷-2-基)-1-氧代-3-苯基丙-2-基)氨基)-1-氧代丙-2-基)氨基)-1-氧代丙-2-基)-2-甲基噻唑-5-甲酰胺（ONX0912）和(S)-3-(4-甲氧基苯基)-N-((S)-1-((S)-2-环氧乙烷-2-基)-1-氧代-3-苯基丙-2-基)-2-((S)-2-(2-吗啉乙酰胺基)丙酰胺基)丙酰胺（ONX0914），是否可以逃避两种已建立的 BTZ 耐药机制：1）这些 PI 靶向的蛋白酶体 β5 亚基（PSMB5）的突变，和 2）由 ATP 结合盒转运蛋白介导的药物外排。THP1 髓样亚系获得对 BTZ（54 至 235 倍）的耐药性，这是由于 PSMB5 基因的突变引起的，这些亚系对卡非佐米（9 至 32 倍）、ONX0912（39 至 62 倍）和 ONX0914（27 至 97 倍）表现出明显的交叉耐药性。至于 ATP 结合盒转运蛋白介导的外排，P-糖蛋白（Pgp）/多药耐药蛋白 1 过度表达的淋巴样 CEM/VLB 细胞对卡非佐米（114 倍）、ONX0912（23 倍）和 ONX0914（162 倍）表现出显著的耐药性，而对 BTZ（4.5 倍）的耐药性较低。同样，这些 CEM/VLB 细胞中与 β5 亚基相关的糜蛋白酶样蛋白酶体活性明显受到抑制。对来自类风湿关节炎初治患者的外周血单核细胞的体外分析表明，尽管基础 Pgp 水平较低，但 Pgp 表达会损害卡非佐米和 ONX0914 的抑制作用。然而，使用 P121（逆转素 121），一种 Pgp 转运抑制剂，可以恢复 CEM/VLB 细胞和外周血单核细胞中 PI 的抑制作用。这些结果表明，这些 PI 的药理活性可能受到涉及 PSMB5 突变和 Pgp 外排的耐药机制的阻碍。
