21 research outputs found
Rice (Oryza sativa) TIR1 and 5â˛adamantyl-IAA significantly improve the auxin-inducible degron system in Schizosaccharomyces pombe
The auxin-inducible degron (AID) system is a powerful tool to induce targeted degradation of proteins in eukaryotic model organisms. The efficiency of the existing Schizosaccharomyces pombe AID system is limited due to the fusion of the F-box protein TIR1 protein to the SCF component, Skp1 (Skp1-TIR1). Here, we report an improved AID system for S. pombe that uses the TIR1 from Oryza sativa (OsTIR1) not fused to Skp1. Furthermore, we demonstrate that degradation efficiency can be improved by pairing an OsTIR1 auxin-binding site mutant, OsTIR1, with an auxin analogue, 5â˛adamantyl-IAA (AID2). We provide evidence for the enhanced functionality of the OsTIR1 AID and AID2 systems by application to the essential DNA replication factor Mcm4 and to a non-essential recombination protein, Rad52. Unlike AID, no detectable auxin-independent depletion of AID-tagged proteins was observed using AID
Cytotoxic activity of the histone deacetylase 3-Selective inhibitor Pojamide on MDA-MB-231 triple-negative breast cancer cells
We examined the effects of the ferrocene-based histone deacetylase-3 inhibitor Pojamide (N1-(2-aminophenyl)-N8-ferrocenyloctanediamide) and its two derivatives N1-(2-aminophenyl)-N6-ferrocenyladipamide and N1-(2-aminophenyl)-N8-ferroceniumoctanediamide tetrafluoroborate on triple-negative MDA-MB-231 breast cancer cells. Viability/growth assays indicated that only the first two compounds at 70 ÎźM concentration caused an approximate halving of cell number after 24 h of exposure, whereas the tetrafluoroborate derivative exerted no effect on cell survival nor proliferation. Flow cytometric and protein blot analyses were performed on cells exposed to both Pojamide and the ferrocenyladipamide derivative to evaluate cell cycle distribution, apoptosis/autophagy modulation, and mitochondrial metabolic state in order to assess the cellular basis of the cytotoxic effect. The data obtained show that the cytotoxic effect of the two deacetylase inhibitors may be ascribed to the onset of non-apoptotic cell death conceivably linked to a down-regulation of autophagic processes and an impairment of mitochondrial function with an increase in intracellular reactive oxygen species. Our work expands the list of autophagy-regulating drugs and also provides a further example of the role played by the inhibition of autophagy in breast cancer cell death. Moreover, the compounds studied may represent attractive and promising targets for subsequent molecular modeling for anti-neoplastic agents in malignant breast cancer
Probing the anticancer action of novel ferrocene analogues of MNK inhibitors
Two novel ferrocene-containing compounds based upon a known MNK1/2 kinase (MAPK-interacting kinase) inhibitor have been synthesized. The compounds were designed to use the unique shape of ferrocene to exploit a large hydrophobic pocket in MNK1/2 that is only partially occupied by the original compound. Screening of the ferrocene analogues showed that both exhibited potent anticancer effects in several breast cancer and AML (acute myeloid leukemia) cell lines, despite a loss of MNK potency. The most potent ferrocene-based compound 5 was further analysed in vitro in MDA-MB-231 (triple negative breast cancer cells). Doseâresponse curves of compound 5 for 2D assay and 3D assay generated IC50 values (half maximal inhibitory concentration) of 0.55 ÂľM and 1.25 ÂľM, respectively
Synthesis of a thiazole library via an iridium-catalyzed sulfur ylide insertion reaction
A library of thiazoles and selenothiazoles were synthesized via Ir-catalyzed ylide insertion chemistry. This process is a functional group, particularly heterocycle-substituent tolerant. This was applied to the synthesis of fanetizole, an anti-inflammatory drug, and a thiazole-containing drug fragment that binds to the peptidyl-tRNA hydrolase (Pth) in Neisseria gonorrheae bacteria
Oxygenated cyclopentenones via the pauson-khand reaction of silyl enol ether substrates
We report here the application of silyl enol ether moieties as efficient alkene coupling partners within cobalt-mediated intramolecular Pauson-Khand reactions. This cyclization strategy delivers synthetically valuable oxygenated cyclopentenone products in yields of â¤93% from both ketone- and aldehyde-derived silyl enol ethers, incorporates both terminal and internal alkyne partners, and delivers a variety of decorated systems, including more complex tricyclic structures. Facile removal of the silyl protecting group reveals oxygenated sites for potential further elaboration
Scale-up and optimization of the synthesis of dual CBP/BRD4 inhibitor ISOX-DUAL
ISOX-DUAL is a dual inhibitor of CBP/p300 (IC50 = 0.65 ÎźM) and BRD4 (IC50 = 1.5 ÎźM) bromodomains, and a useful chemical probe for epigenetic research. Aspects of the published synthetic route to this compound and its analogues are small-scale, poor-yielding or simply unamenable to scale-up without optimization. Herein we describe the development of a refined synthesis that circumvents the challenges of the original report, with notable improvements to several of the key synthetic transformations. Moreover, a general Suzuki Miyaura protocol for the late stage installation of alternative dimethyl-isoxazole acetyl-lysine (KAc) binding motifs is presented
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Room temperature Cu(II) radical-triggered alkyne C-H activation
A dimeric Cu(II) complex [Cu(II)2L2(Îź2-Cl)Cl] (1) built from an asymmetric tridentate ligand (2-(((2-aminocyclohexyl)imino)methyl) -4,6-di-tert-butylphenol) and weakly coordinating anions has been synthesized and structurally characterized. In dichloromethane solution, 1 exists in a monomeric [Cu(II)LCl] (1â˛) (85%)âdimeric (1) (15%) equilibrium, and cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) studies indicate structural stability and redox retention. Addition of phenylacetylene to the CH2Cl2 solution populates 1Ⲡand leads to the formation of a transient radical species. Theoretical studies support this notion and show that the radical initiates an alkyne CâH bond activation process via a four-membered ring (Cu(II)âO¡¡¡HâCalkyne) intermediate. This unusual CâH activation method is applicable for the efficient synthesis of propargylamines, without additives, within 16 h, at low loadings and in noncoordinating solvents including late-stage functionalization of important bioactive molecules. Single-crystal X-ray diffraction studies, postcatalysis, confirmed the frameworkâs stability and showed that the metal center preserves its oxidation state. The scope and limitations of this unconventional protocol are discussed
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Metallodrug profiling against SARS-CoV-2 target proteins identifies highly potent inhibitors of the S/ACE2 interaction and the papain-like protease PL<sup>pro</sup>
The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has called for an urgent need for dedicated antiviral therapeutics. Metal complexes are commonly underrepresented in compound libraries that are used for screening in drug discovery campaigns, however, there is growing evidence for their role in medicinal chemistry. Based on previous results, we have selected more than 100 structurally diverse metal complexes for profiling as inhibitors of two relevant SARS-CoV-2 replication mechanisms, namely the interaction of the spike (S) protein with the ACE2 receptor and the papain-like protease PLpro. In addition to many well-established types of mononuclear experimental metallodrugs, the pool of compounds tested was extended to approved metal-based therapeutics such as silver sulfadiazine and thiomersal, as well as polyoxometalates (POMs). Among the mononuclear metal complexes, only a small number of active inhibitors of the S/ACE2 interaction was identified, with titanocene dichloride as the only strong inhibitor. However, among the gold and silver containing complexes many turned out to be very potent inhibitors of PLpro activity. Highly promising activity against both targets was noted for many POMs. Selected complexes were evaluated in antiviral SARS-CoV-2 assays confirming activity for gold complexes with N-heterocyclic carbene (NHC) or dithiocarbamato ligands, a silver NHC complex, titanocene dichloride as well as a POM compound. These studies might provide starting points for the design of metal-based SARS-CoV-2 antiviral agents
Probing BRD inhibition substituent effects in bulky analogues of (+)-JQ1
A series of bulky organometallic and organic analogues of the bromodomain (BRD) inhibitor (+)-JQ1 have been prepared. The most potent, N-[(adamantan-1-yl)methyl]-2-[(9S)-7-(4-chlorophenyl)-4,5,13-trimethyl-3-thia-1,8,11,12-tetraazatricyclo[8.3.0.02,6]trideca-2(6),4,7,10,12-pentaen-9-yl]acetamide, 2e, showed excellent potency with an KD=ca. 130 nm vs. BRD4(1) and a ca. 2-fold selectivity over BRD4(2) (KD=ca. 260 nm). Its binding to the first bromodomain of BRD4 was determined by a protein cocrystal structure
Deliberately losing control of C-H activation processes in the design of small molecule fragment arrays targeting peroxisomal metabolism
Combined photochemical arylation, ânuisance effectâ (S N Ar) reaction sequences have been employed in the design of small arrays for immediate deployment in medium throughput Xâray proteinâligand structure determination. Reactions have been deliberately let âout of control,â in terms of selectivity; for example the orthoâarylation of 2âphenylpyridine gave five products resulting from monoâ, bisâ arylations combined with S N Ar processes. As a result, a number of crystallographic hits against NUDT7, a key peroxisomal CoA ester hydrolase, have been identified