Here, we present remarkable epoxyketone-based proteasome inhibitors with low nanomolar in vitro potency for blood-stage Plasmodium falciparum and low cytotoxicity for human cells. Our best compound has more than 2,000-fold greater selectivity for erythrocytic-stage P. falciparum over HepG2 and H460 cells, which is largely driven by the accommodation of the parasite proteasome for a D-amino acid in the P3 position and the preference for a difluorobenzyl group in the P1 position. We isolated the proteasome from P. falciparum cell extracts and determined that the best compound is 171-fold more potent at inhibiting the β5 subunit of P. falciparum proteasome when compared to the same subunit of the human constitutive proteasome. These compounds also significantly reduce parasitemia in a P. berghei mouse infection model and prolong survival of animals by an average of 6 days. The current epoxyketone inhibitors are ideal starting compounds for orally bioavailable anti-malarial drugs.
- MeSH
- antimalarika * farmakologie MeSH
- inhibitory proteasomu chemie MeSH
- lidé MeSH
- myši MeSH
- Plasmodium falciparum MeSH
- Plasmodium * MeSH
- proteasomový endopeptidasový komplex chemie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Wedelolactone is a multi-target natural plant coumestan exhibiting cytotoxicity towards cancer cells. Although several molecular targets of wedelolactone have been recognized, the molecular mechanism of its cytotoxicity has not yet been elucidated. In this study, we show that wedelolactone acts as an inhibitor of chymotrypsin-like, trypsin-like, and caspase-like activities of proteasome in breast cancer cells. The proteasome inhibitory effect of wedelolactone was documented by (i) reduced cleavage of fluorogenic proteasome substrates; (ii) accumulation of polyubiquitinated proteins and proteins with rapid turnover in tumor cells; and (iii) molecular docking of wedelolactone into the active sites of proteasome catalytic subunits. Inhibition of proteasome by wedelolactone was independent on its ability to induce reactive oxygen species production by redox cycling with copper ions, suggesting that wedelolactone acts as copper-independent proteasome inhibitor. We conclude that the cytotoxicity of wedelolactone to breast cancer cells is partially mediated by targeting proteasomal protein degradation pathway. Understanding the structural basis for inhibitory mode of wedelolactone might help to open up new avenues for design of novel compounds efficiently inhibiting cancer cells.
- MeSH
- inhibitory proteasomu chemie farmakologie toxicita MeSH
- kumariny chemie farmakologie toxicita MeSH
- lidé MeSH
- měď metabolismus MeSH
- nádorové buněčné linie MeSH
- nádory prsu metabolismus MeSH
- proteasomový endopeptidasový komplex chemie metabolismus MeSH
- proteolýza MeSH
- reaktivní formy kyslíku metabolismus MeSH
- simulace molekulového dockingu MeSH
- ubikvitinace MeSH
- vazba proteinů MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Ubiquitylation controls protein function and degradation. Therefore, ubiquitin ligases need to be tightly controlled. We discovered an evolutionarily conserved allosteric restraint mechanism for Nedd4 ligases and demonstrated its function with diverse substrates: the yeast soluble proteins Rpn10 and Rvs167, and the human receptor tyrosine kinase FGFR1 and cardiac IKS potassium channel. We found that a potential trimerization interface is structurally blocked by the HECT domain α1-helix, which further undergoes ubiquitylation on a conserved lysine residue. Genetic, bioinformatics, biochemical and biophysical data show that attraction between this α1-conjugated ubiquitin and the HECT ubiquitin-binding patch pulls the α1-helix out of the interface, thereby promoting trimerization. Strikingly, trimerization renders the ligase inactive. Arginine substitution of the ubiquitylated lysine impairs this inactivation mechanism and results in unrestrained FGFR1 ubiquitylation in cells. Similarly, electrophysiological data and TIRF microscopy show that NEDD4 unrestrained mutant constitutively downregulates the IKS channel, thus confirming the functional importance of E3-ligase autoinhibition.
- MeSH
- draslíkové kanály řízené napětím chemie metabolismus MeSH
- endozomální třídící komplexy pro transport metabolismus MeSH
- lidé MeSH
- mikrofilamentové proteiny chemie metabolismus MeSH
- multimerizace proteinu * MeSH
- proteasomový endopeptidasový komplex chemie metabolismus MeSH
- receptor fibroblastových růstových faktorů, typ 1 chemie metabolismus MeSH
- Saccharomyces cerevisiae - proteiny chemie metabolismus MeSH
- ubikvitinace * MeSH
- ubikvitinligasy metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Inhibition of proteasome, a proteolytic complex responsible for the degradation of ubiquitinated proteins, has emerged as a powerful strategy for treatment of multiple myeloma (MM), a plasma cell malignancy. First-in-class agent, bortezomib, has demonstrated great positive therapeutic efficacy in MM, both in pre-clinical and in clinical studies. However, despite its high efficiency, a large proportion of patients do not achieve sufficient clinical response. Therefore, the development of a second-generation of proteasome inhibitors (PIs) with improved pharmacological properties was needed. Recently, several of these new agents have been introduced into clinics including carfilzomib, marizomib and ixazomib. Further, new orally administered second-generation PI oprozomib is being investigated. This review provides an overview of main mechanisms of action of PIs in MM, focusing on the ongoing development and progress of novel anti-proteasome therapeutics.
The idea of "repurposing" of existing drugs provides an effective way to develop and identify new therapies. Disulfiram (Antabuse), a drug commonly used for the treatment of alcoholism, shows promising anticancer activity in both preclinical and clinical studies. In the human body, disulfiram is rapidly converted to its reduced metabolite, diethyldithiocarbamate. If copper ions are available, a bis(diethyldithiocarbamate)-copper(II) complex is formed. Disulfiram's selective anticancer activity is attributed to the copper(II) complex's ability to inhibit the cellular proteasome. It is assumed that the complex inhibits the proteasome by a mechanism that is distinct to the clinically used drug bortezomib, targeting the 19S rather than the 20S proteasome. This difference could be explained by inhibition of the JAMM domain of the POH1 subunit within the lid of the 19S proteasome.
- MeSH
- antitumorózní látky chemie farmakologie terapeutické užití MeSH
- dithiokarb chemie MeSH
- inhibitory proteasomu chemie farmakologie terapeutické užití MeSH
- komplexní sloučeniny chemie farmakologie terapeutické užití MeSH
- kyseliny boronové chemie farmakologie terapeutické užití MeSH
- lidé MeSH
- měď chemie MeSH
- nádorové buněčné linie MeSH
- nádory prsu farmakoterapie metabolismus patologie MeSH
- oxidační stres účinky léků MeSH
- proteasomový endopeptidasový komplex chemie metabolismus MeSH
- pyraziny chemie farmakologie terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
