title: Inactivating PSMB5 mutations and P-glycoprotein (multidrug resistance-associated protein/ATP-binding cassette B1) mediate resistance to proteasome inhibitors: ex vivo efficacy of (immuno)proteasome inhibitors in mononuclear blood cells from patients with rheumatoid arthritis.
abstract: 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.
authors.affiliation: Department of Rheumatology, VU Institute for Cancer and Immunology, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Sue Ellen
authors.initials: SE
authors.lastname: Verbrugge
authors.forename: Yehuda G
authors.initials: YG
authors.lastname: Assaraf
authors.forename: Ben A C
authors.initials: BA
authors.lastname: Dijkmans
authors.forename: George L
authors.initials: GL
authors.lastname: Scheffer
authors.forename: Marjon
authors.initials: M
authors.lastname: Al
authors.forename: Debby
authors.initials: D
authors.lastname: den Uyl
authors.forename: Ruud
authors.initials: R
authors.lastname: Oerlemans
authors.forename: Elena T
authors.initials: ET
authors.lastname: Chan
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kirk
authors.forename: Godefridus J
authors.initials: GJ
authors.lastname: Peters
authors.forename: Joost W
authors.initials: JW
authors.lastname: van der Heijden
authors.forename: Tanja D
authors.initials: TD
authors.lastname: de Gruijl
authors.forename: Rik J
authors.initials: RJ
authors.lastname: Scheper
authors.forename: Gerrit
authors.initials: G
authors.lastname: Jansen
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000502:physiology*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism*; D001897:Boronic Acids / Q000494:pharmacology / Q000627:therapeutic use; D000069286:Bortezomib; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000502:physiology; D057809:HEK293 Cells; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D009842:Oligopeptides / Q000494:pharmacology / Q000627:therapeutic use; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D061988:Proteasome Inhibitors; D011719:Pyrazines / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D001897:Boronic Acids; C554738:ONX 0912; D009842:Oligopeptides; C542291:PR-957; D061988:Proteasome Inhibitors; D011719:Pyrazines; D000069286:Bortezomib; C088874:PSMB5 protein, human; D046988:Proteasome Endopeptidase Complex