Crystal Structure of the Human 20S Proteasome in Complex with Carfilzomib

Harshbarger, Wayne; Miller, Charles S.; Diedrich, Chandler; Sacchettini, James C.

doi:10.1016/j.str.2014.11.017

Cited by 144 publications

(169 citation statements)

References 20 publications

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“…Carfilzomib (Kyprolis ® ), a peptide epoxyketone (Figure 1), represents a new generation of proteasome inhibitors. It selectively binds to the N-terminal threonine of the proteasome via two covalent bonds to form a morpholino ring (Harshbarger et al, 2015), and has demonstrated favorable clinical safety and efficacy profiles compared to bortezomib (Kuhn et al, 2007). Carfilzomib has been approved for use as a single agent and in combination with lenalidomide and dexamethasone in patients with relapsed or/and refractory multiple myeloma (RRMM) (Thompson, 2013).…”

Section: Introductionmentioning

confidence: 99%

In Vitro Metabolism of Oprozomib, an Oral Proteasome Inhibitor: Role of Epoxide Hydrolases and Cytochrome P450s

et al. 2017

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Oprozomib is an oral proteasome inhibitor currently under investigation in patients with hematologic malignancies or solid tumors. Oprozomib elicits potent pharmacological actions by forming a covalent bond with the active site -terminal threonine of the 20S proteasome. Oprozomib has a short half-life across preclinical species and in patients due to systemic clearance via metabolism. Potential for drug-drug interactions (DDIs) could alter the exposure of this potent therapeutic; therefore, a thorough investigation of pathways responsible for metabolism is required. In the present study, the major drug-metabolizing enzyme responsible for oprozomib metabolism was identified in vitro. A diol of oprozomib was found to be the predominant metabolite in human hepatocytes, which formed via direct epoxide hydrolysis. Using recombinant epoxide hydrolases (EHs) and selective EH inhibitors in liver microsomes, microsomal EH (mEH) but not soluble EH (sEH) was found to be responsible for oprozomib diol formation. Coincubation with 2-nonylsulfanyl-propionamide, a selective mEH inhibitor, resulted in a significant decrease in oprozomib disappearance (>80%) with concurrent complete blockage of diol formation in human hepatocytes. On the contrary, a selective sEH inhibitor did not affect oprozomib metabolism. Pretreatment of hepatocytes with the -cytochrome P450 (P450) inhibitor 1-aminobenzotriazole resulted in a modest reduction (∼20%) of oprozomib metabolism. These findings indicated that mEH plays a predominant role in oprozomib metabolism. Further studies may be warranted to determine whether drugs that are mEH inhibitors cause clinically significant DDIs with oprozomib. On the other hand, pharmacokinetics of oprozomib is unlikely to be affected by coadministered P450 and sEH inhibitors and/or inducers.

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Section: Introductionmentioning

confidence: 99%

In Vitro Metabolism of Oprozomib, an Oral Proteasome Inhibitor: Role of Epoxide Hydrolases and Cytochrome P450s

et al. 2017

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“…The ubiquitin-proteasome pathways are essential parts of important biological processes, such as cell division, differentiation, innate immunity, adaptive immunity, regulation of gene expression, and the response to proteotoxic stress (1)(2)(3)(4). The proteasome is also an important therapeutic target in multiple myeloma (5,6).…”

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confidence: 99%

“…Heptameric α-rings, positioned on each side of the catalytic chamber, control substrate entry into this space. Opening of a channel within the α-ring is thought to result from association of the RP and the CP (5,(11)(12)(13). However, the mechanism of the core regulatory step of the proteasome channel opening remains mysterious.…”

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confidence: 99%

“…High-resolution structures of the isolated CP have been available for several species (5,12,13). The intact proteasome has not been resolved to a level at which a reliable Cα-backbone can be traced with spatial assignment of amino acids, although major advances have been made in recent years (2,3,(7)(8)(9)(10)(11)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25).…”

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Structural basis for dynamic regulation of the human 26S proteasome

Chen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The proteasome is the major engine of protein degradation in all eukaryotic cells. At the heart of this machine is a heterohexameric ring of AAA (ATPases associated with diverse cellular activities) proteins that unfolds ubiquitylated target proteins that are concurrently translocated into a proteolytic chamber and degraded into peptides. Using cryoelectron microscopy, we determined a near–atomic-resolution structure of the 2.5-MDa human proteasome in its ground state, as well as subnanometer-resolution structures of the holoenzyme in three alternative conformational states. The substrate-unfolding AAA-ATPase channel is narrowed by 10 inward-facing pore loops arranged into two helices that run in parallel with each other, one hydrophobic in character and the other highly charged. The gate of the core particle was unexpectedly found closed in the ground state and open in only one of the alternative states. Coordinated, stepwise conformational changes of the regulatory particle couple ATP hydrolysis to substrate translocation and regulate gating of the core particle, leading to processive degradation.

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“…Using the Amber12:EHT force field and the crystal structure collected by Harshbarger et al, 26 the minimum energy conformation of the β4β5 dimer bound to 7 and 8 was calculated. Each inhibitor was modeled as a hemiacetal adduct of the catalytic Thr1.…”

Section: Acs Medicinal Chemistry Lettersmentioning

confidence: 99%

Synthesis and Evaluation of Macrocyclic Peptide Aldehydes as Potent and Selective Inhibitors of the 20S Proteasome

Wilson

Meininger

Strater

et al. 2016

ACS Med. Chem. Lett.

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This research explores the first design and synthesis of macrocyclic peptide aldehydes as potent inhibitors of the 20S proteasome. Two novel macrocyclic peptide aldehydes based on the ring-size of the macrocyclic natural product TMC-95 were prepared and evaluated as inhibitors of the 20S proteasome. Both compounds inhibited in the low nanomolar range and proved to be selective for the proteasome over other serine and cysteine proteases, particularly when compared to linear analogues with similar amino acid sequences. In HeLa cells, both macrocycles efficiently inhibited activation of nuclear factor-κB (NF-κB) transcription factor by blocking proteasomal degradation of the inhibitor protein IκBα after cytokine stimulation. Due to their covalent mechanism of binding these compounds represent a 1000-fold increase in inhibitory potency over previously reported noncovalently binding TMC-95 analogues. Molecular modeling of the macrocyclic peptides confirms the preference of the large S 3 pocket for large, hydrophobic residues and the ability to exploit this to improve selectivity of proteasome inhibitors.

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Crystal Structure of the Human 20S Proteasome in Complex with Carfilzomib

Cited by 144 publications

References 20 publications

In Vitro Metabolism of Oprozomib, an Oral Proteasome Inhibitor: Role of Epoxide Hydrolases and Cytochrome P450s

In Vitro Metabolism of Oprozomib, an Oral Proteasome Inhibitor: Role of Epoxide Hydrolases and Cytochrome P450s

Structural basis for dynamic regulation of the human 26S proteasome

Synthesis and Evaluation of Macrocyclic Peptide Aldehydes as Potent and Selective Inhibitors of the 20S Proteasome

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