Anticancer applications of allosteric inhibitors of proteasome.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e23066-e23066
Author(s):  
Pawel A. Osmulski ◽  
Jodie Cropper ◽  
Matt Giletto ◽  
Corey Jones ◽  
Caleb Killer ◽  
...  

e23066 Background: Proteasome as a hub protease of the ubiquitin proteasome pathway is an established anticancer drug target. Several drugs that inhibit proteasome are currently used to successfully treat aggressive blood cancers. These drugs are based on their competition with protein substrates of proteasome. However, efficacy of these drugs toward solid cancers is inadequate. Besides, the side effects and developing drug resistance are increasingly hampering the therapy. Therefore, there is an unmet challenge to develop new types of proteasome targeting compounds that are efficient against solid cancers and utilize other mechanisms to stop proteasome. Here we present a compound with a novel molecular mechanism, potentially bypassing limitations of the available drugs. Methods: We rationally designed and synthesized a series of small molecule “B” compounds, derivatives of a binding domain of seco-rapamycin that noncompetitively interfere with peptidase activities of proteasome. We tested effects of the compounds in vitro on purified proteasome, in cellulo with selected cancer cell lines and in a xenograft mouse model of prostate cancer. Results: We found that compound B1 binds to the catalytic core of proteasome far from the catalytic sites, destabilizes assembly of the 26S proteasome responsible for digest of polyUb substrates and allosterically inhibits its proteolytic activities. Molecularly, B1 impedes the gating mechanism responsible for substrate uptake as found with AFM. Tryptophan fluorescence indicates that B1 changes proteasome fold and the binding mode of competitive inhibitors. B1 substantially decreases viability of selected cancer cell lines and shifts their mechanical phenotype toward noncancerous status. B1 synergizes with bortezomib decreasing the IC50 5-10 fold. In a xenograft hormone resistant prostate cancer model, B1 treatment leads to shrinkage of the tumor size, decreases enumeration of aggressive, EpCAM+ CTCs and shifts the macrophage profile toward predator M1 type. Conclusions: B1 compounds constitute a new class of noncompetitive allosteric inhibitors of proteasome that could be useful to develop to treat aggressive prostate cancers alone or in synergy with competitive inhibitors.

2006 ◽  
Vol 175 (4S) ◽  
pp. 258-258
Author(s):  
Ruth Schwaninger ◽  
Cyrill A. Rentsch ◽  
Antoinette Wetterwald ◽  
Irena Klima ◽  
Gabri Van der Pluijm ◽  
...  

1992 ◽  
Vol 68 (06) ◽  
pp. 662-666 ◽  
Author(s):  
W Hollas ◽  
N Hoosein ◽  
L W K Chung ◽  
A Mazar ◽  
J Henkin ◽  
...  

SummaryWe previously reported that extracellular matrix invasion by the prostate cancer cell lines, PC-3 and DU-145 was contingent on endogenous urokinase being bound to a specific cell surface receptor. The present study was undertaken to characterize the expression of both urokinase and its receptor in the non-invasive LNCaP and the invasive PC-3 and DU-145 prostate cells. Northern blotting indicated that the invasive PC-3 cells, which secreted 10 times more urokinase (680 ng/ml per 106 cells per 48 h) than DU-145 cells (63 ng/ml per 106 cells per 48 h), had the most abundant transcript for the plasminogen activator. This, at least, partly reflected a 3 fold amplification of the urokinase gene in the PC-3 cells. In contrast, urokinase-specific transcript could not be detected in the non-invasive LNCaP cells previously characterized as being negative for urokinase protein. Southern blotting indicated that this was not a consequence of deletion of the urokinase gene. Crosslinking of radiolabelled aminoterminal fragment of urokinase to the cell surface indicated the presence of a 51 kDa receptor in extracts of the invasive PC-3 and DU-145 cells but not in extracts of the non-invasive LNCaP cells. The amount of binding protein correlated well with binding capacities calculated by Scatchard analysis. In contrast, the steady state level of urokinase receptor transcript was a poor predictor of receptor display. PC-3 cells, which were equipped with 25,000 receptors per cell had 2.5 fold more steady state transcript than DU-145 cells which displayed 93,000 binding sites per cell.


2020 ◽  
Vol 16 (6) ◽  
pp. 735-749 ◽  
Author(s):  
Özgür Yılmaz ◽  
Burak Bayer ◽  
Hatice Bekçi ◽  
Abdullahi I. Uba ◽  
Ahmet Cumaoğlu ◽  
...  

Background:: Prostate cancer is still one of the serious causes of mortality and morbidity in men. Despite recent advances in anticancer therapy, there is a still need of novel agents with more efficacy and specificity in the treatment of prostate cancer. Because of its function on angiogenesis and overexpression in the prostate cancer, methionine aminopeptidase-2 (MetAP-2) has been a potential target for novel drug design recently. Objective:: A novel series of Flurbiprofen derivatives N-(substituted)-2-(2-(2-fluoro-[1,1'- biphenyl]-4-il)propanoyl)hydrazinocarbothioamide (3a-c), 4-substituted-3-(1-(2-fluoro-[1,1'-biphenyl]- 4-yl)ethyl)-1H-1,2,4-triazole-5(4H)-thione (4a-d), 3-(substitutedthio)-4-(substituted-phenyl)- 5-(1-(2-fluoro-[1,1'-biphenyl]-4-yl)ethyl)-4H-1,2,4-triazole (5a-y) were synthesized. The purpose of the research was to evaluate these derivatives against MetAP-2 in vitro and in silico to obtain novel specific and effective anticancer agents against prostate cancer. Methods: The chemical structures and purities of the compounds were defined by spectral methods (1H-NMR, 13C-NMR, HR-MS and FT-IR) and elemental analysis. Anticancer activities of the compounds were evaluated in vitro by using MTS method against PC-3 and DU-143 (androgenindependent human prostate cancer cell lines) and LNCaP (androgen-sensitive human prostate adenocarcinoma) prostate cancer cell lines. Cisplatin was used as a positive sensitivity reference standard. Results:: Compounds 5b and 5u; 3c, 5b and 5y; 4d and 5o showed the most potent biological activity against PC3 cancer cell line (IC50= 27.1 μM, and 5.12 μM, respectively), DU-145 cancer cell line (IC50= 11.55 μM, 6.9 μM and 9.54 μM, respectively) and LNCaP cancer cell line (IC50= 11.45 μM and 26.91 μM, respectively). Some compounds were evaluated for their apoptotic caspases protein expression (EGFR/PI3K/AKT pathway) by Western blot analysis in androgen independent- PC3 cells. BAX, caspase 9, caspsase 3 and anti-apoptotic BcL-2 mRNA levels of some compounds were also investigated. In addition, molecular modeling studies of the compounds on MetAP-2 enzyme active site were evaluated in order to get insight into binding mode and energy. Conclusion:: A series of Flurbiprofen-thioether derivatives were synthesized. This study presented that some of the synthesized compounds have remarkable anticancer and apoptotic activities against prostate cancer cells. Also, molecular modeling studies exhibited that there is a correlation between molecular modeling and anticancer activity results.


Author(s):  
Rafat M. Mohareb ◽  
Yara R. Milad ◽  
Reem A. El-Ansary

Background:: Recently multi-component reactions producing pyran and pyridine derivatives acquired a special attention due to their wide range of pharmacological activities especially the therapeutic activities. Through the market it was found that many pharmacological drugs containing the pyran and pyridine nucleus were known. Objective:: We are aiming in this work to synthesize target molecules not only possess anti-tumor activities but also kinase inhibitors. The target molecules were obtained starting from cyclohexan-1,3-dione followed by its heterocyclization reactions to produce anticancer target molecules. Methods:: This work demonstrated multi-component reactions of cyclohexan-1,3-dione with aromatic aldehydes and diethylmalonate using triethylamine as a catalyst to give the 7,8-dihydro-4H-chromen-5(6H)-one derivatives 4a-c. The reaction of compounds 4a-c with either of hydrazine hydrate of phenylhydrazine gave the chromeno[2,3-c]pyrazole derivatives 5a-f, respectively. In addition, further heterocyclization reactions were adopted to give the chromeno[3,2-d]isoxazole, chromene-3-carboxamide derivatives. Moreover, the multi-component reaction of cyclohexan-1,3-dione (1) with either of aromatic aldehydes and diethylmalonate using a catalytic amount of ammonium acetate gave the 1,4,5,6,7,8-hexahydroquinoline derivatives 13a-c. The anti-proliferative activities of the synthesized compounds toward the six cancer cell lines namely A549, H460, HT-29, MKN-45, U87MG, and SMMC-7721 were studied. In addition the c-Met enzymatic activities and inhibition toward the prostate cancer cell PC-3 were measured. Results:: Anti-proliferative evaluations, c-Met enzymatic activities and inhibition toward the prostate cancer cell PC-3 were measured and the results obtained in most cases, indicated that the presence of electronegative Cl group through the molecule favour the inhibitions. Conclusion:: The compounds with high anti-proliferative activity towards the cancer cell lines were 4a, 4b, 6d, 6e, 6f, 10e, 10f, 12c, 14e, 14f, 15c, 16d, 16e, 16f, 19c and 20c. Compounds 4b, 6c, 6d, 8b, 10c, 10d, 12b, 13b, 14c, 14d, 15b, 16c, 16d, 17b, 17c, 19b, 20b and 20c exhibited high potency against c-Met kinase and compounds 4a, 4b, 6b, 6c, 6d, 6f, 8b, 8c, 10c, 10d, 10e, 12b, 12c, 13a, 13b, 13c, 14c, 14d, 14e, 14f, 15b, 15c, 16b, 16c, 16d, 17b, 17c, 19c, 19d, 20a, 20b and 20c displayed high inhibitions toward PC-3 cell line.


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