| 1. |
- Selvaraju, Karthik, et al.
(författare)
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Inhibition of proteasome deubiquitinase activity : a strategy to overcome resistance to conventional proteasome inhibitors?
- 2015
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Ingår i: Drug resistance updates. - : Elsevier BV. - 1368-7646 .- 1532-2084. ; 21-22, s. 20-29
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Forskningsöversikt (refereegranskat)abstract
- Although more traditionally associated with degradation and maintenance of protein homeostasis, the ubiquitin-proteasome system (UPS) has emerged as a critical component in the regulation of cancer cell growth and survival. The development of inhibitors that block the proteolytic activities of the proteasome have highlighted its suitability as a bona fide anti-cancer drug target. However, key determinants including the development of drug resistance and dose-limiting toxicity call for the identification of alternative components of the UPS for novel drug targeting. Recently the deubiquitinases (DUBS), a diverse family of enzymes that catalyze ubiquitin removal, have attracted significant interest as targets for the development of next generation UPS inhibitors. In particular, pharmacological inhibition of the proteasomal cysteine DUBs (i.e., USP14 and UCHL5) has been shown to be particularly cytotoxic to cancer cells and inhibit tumour growth in several in vivo models. In the current review we focus on the modes of action of proteasome DUB inhibitors and discus the potential of DUB inhibitors to circumvent acquired drug resistance and provide a therapeutic option for the treatment of cancer.
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| 2. |
- Wang, Xin, et al.
(författare)
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Synthesis and Evaluation of Derivatives of the Proteasome Deubiquitinase Inhibitor b-AP15
- 2015
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Ingår i: Chemical Biology and Drug Design. - : Wiley. - 1747-0277 .- 1747-0285. ; 86:5, s. 1036-1048
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Tidskriftsartikel (refereegranskat)abstract
- The ubiquitin-proteasome system (UPS) is increasingly recognized as a therapeutic target for the development of anticancer therapies. The success of the 20S proteasome core particle (20S CP) inhibitor bortezomib in the clinical management of multiple myeloma has raised the possibility of identifying other UPS components for therapeutic intervention. We previously identified the small molecule b-AP15 as an inhibitor of 19S proteasome deubiquitinase (DUB) activity. Building upon our previous data, we performed a structure-activity relationship (SAR) study on b-AP15 and identified VLX1570 as an analog with promising properties, including enhanced potency and improved solubility in aqueous solution. In silico modeling was consistent with interaction of VLX1570 with key cysteine residues located at the active sites of the proteasome DUBs USP14 and UCHL5. VLX1570 was found to inhibit proteasome deubiquitinase activity in vitro in a manner consistent with competitive inhibition. Furthermore, using active-site-directed probes, VLX1570 also inhibited proteasome DUB activity in exposed cells. Importantly, VLX1570 did not show inhibitory activity on a panel of recombinant non-proteasome DUBs, on recombinant kinases, or on caspase-3 activity, suggesting that VLX1570 is not an overtly reactive general enzyme inhibitor. Taken together, our data shows the chemical and biological properties of VLX1570 as an optimized proteasome DUB inhibitor.
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| 3. |
- Zhang, Xiaonan, et al.
(författare)
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Targeting Mitochondrial Function to Treat Quiescent Tumor Cells in Solid Tumors
- 2015
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 16:11, s. 27313-27326
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Forskningsöversikt (refereegranskat)abstract
- The disorganized nature of tumor vasculature results in the generation of microenvironments characterized by nutrient starvation, hypoxia and accumulation of acidic metabolites. Tumor cell populations in such areas are often slowly proliferating and thus refractory to chemotherapeutical drugs that are dependent on an active cell cycle. There is an urgent need for alternative therapeutic interventions that circumvent growth dependency. The screening of drug libraries using multicellular tumor spheroids (MCTS) or glucose-starved tumor cells has led to the identification of several compounds with promising therapeutic potential and that display activity on quiescent tumor cells. Interestingly, a common theme of these drug screens is the recurrent identification of agents that affect mitochondrial function. Such data suggest that, contrary to the classical Warburg view, tumor cells in nutritionally-compromised microenvironments are dependent on mitochondrial function for energy metabolism and survival. These findings suggest that mitochondria may represent an Achilles heel for the survival of slowly-proliferating tumor cells and suggest strategies for the development of therapy to target these cell populations.
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