Members of the casein kinase 1 (CK1) family have emerged as key regulators of cellular signaling and as potential drug targets. Functional annotation of the 7 human isoforms would benefit from isoform-selective inhibitors, allowing studies on the role of these enzymes in normal physiology and disease pathogenesis. However, due to significant sequence homology within the catalytic domain, isoform selectivity is difficult to achieve with conventional small molecules. Here, we used a PROTAC (Proteolysis TArgeting Chimeras) approach to develop a highly selective degrader AH078 (37) targeting CK1δ and CK1ε with excellent selectivity over the highly related CK1α isoform. The developed PROTAC, AH078 (37) selectively degraded CK1δ and CK1ε with a DC50 of 200 nM. Characterization of AH078 (37) revealed a VHL and Ubiquitin-dependent degradation mechanism. Thus, AH078 (37) represents a versatile chemical tool to study CK1δ and CK1ε function in cellular systems.
- MeSH
- Protein Kinase Inhibitors * pharmacology chemistry metabolism MeSH
- Casein Kinase Idelta * antagonists & inhibitors metabolism MeSH
- Casein Kinase 1 epsilon * antagonists & inhibitors metabolism MeSH
- Humans MeSH
- Drug Discovery MeSH
- Proteolysis * drug effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Topoisomerase II alpha and beta (TOP2A and TOP2B) isoenzymes perform essential and non-redundant cellular functions. Anthracyclines induce their potent anti-cancer effects primarily via TOP2A, but at the same time they induce a dose limiting cardiotoxicity through TOP2B. Here we describe the development of the obex class of TOP2 inhibitors that bind to a previously unidentified druggable pocket in the TOP2 ATPase domain to act as allosteric catalytic inhibitors by locking the ATPase domain conformation with the capability of isoform-selective inhibition. Through rational drug design we have developed topobexin, which interacts with residues that differ between TOP2A and TOP2B to provide inhibition that is both selective for TOP2B and superior to dexrazoxane. Topobexin is a potent protectant against chronic anthracycline cardiotoxicity in an animal model. This demonstration of TOP2 isoform-specific inhibition underscores the broader potential to improve drug specificity and minimize adverse effects in various medical treatments.
- MeSH
- Anthracyclines * adverse effects pharmacology MeSH
- DNA Topoisomerases, Type II * metabolism chemistry MeSH
- Topoisomerase II Inhibitors * pharmacology chemistry MeSH
- Cardiotonic Agents * pharmacology chemistry MeSH
- Cardiotoxicity * prevention & control MeSH
- Humans MeSH
- Mice MeSH
- Poly-ADP-Ribose Binding Proteins antagonists & inhibitors metabolism chemistry MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Lipoprotein (a) [Lp(a)] has been recognized as an independent, inherited, causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis, thus representing a major target of residual CV risk. Currently, no drug has been officially approved for lowering Lp(a) levels, and in clinical practice, Lp(a) is mainly used to (re)define CV risk, particularly in individuals at borderline CV risk and people with a family history of premature coronary heart disease, according to various guidelines. Specific Lp(a)-targeted antisense oligonucleotides (ASOs) and small interfering RNA (siRNA) agents have been developed to produce substantial Lp(a) reductions via the inhibition of apo(a) synthesis in the liver. These drugs are conjugated to N-acetylgalactosamine (GalNAc) to ensure their binding to asialoglycoproteins, which are specifically expressed on the surface of the hepatocytes. Such drugs include pelacarsen (an injectable ASO) and olpasiran, zerlasiran, and lepodisiran (injectable siRNA agents). Muvalaplin represents another therapeutic option to lower Lp(a) levels, since it is an oral selective small molecule inhibitor of Lp(a) formation, thus potentially exerting certain advantages in terms of its clinical use. The present narrative review summarizes the available clinical data on the efficacy and safety of these investigational Lp(a)-lowering therapies, as reported in phase 1 and 2 trials. The effects of these drugs on other [aside from Lp(a)] lipid parameters are also discussed. The phase 3 CV trial outcomes are ongoing for some of these agents (i.e., pelacarsen, olpasiran, and lepodisiran) and are briefly mentioned. Overall, there is an urgent need for evidence-based guidelines on Lp(a) reduction in daily clinical practice, following the results of the phase 3 CV trials, as well as for establishing the ideal Lp(a) quantification method (i.e., using an apo(a) isoform-independent assay with appropriate calibrators, reporting the Lp(a) level in molar units).
- Publication type
- Journal Article MeSH
- Review MeSH
The effective treatment of inflammatory diseases, particularly their chronic forms, is a key task of modern medicine. Herein, we report the synthesis and evaluation of biocompatible polymer conjugates based on N-2-(hydroxypropyl)methacrylamide copolymers enabling the controlled release of acetylsalicylic acid (ASA)-based anti-inflammatory drugs under specific stimuli. All polymer nanotherapeutics were proposed as water-soluble drug delivery systems with a hydrodynamic size below 10 nm ensuring suitability for the parenteral application and preventing opsonization by the reticuloendothelial system. The nanotherapeutics bearing an ester-bound ASA exhibited long-term release of the ASA/salicylic acid mixture, while the nanotherapeutics carrying salicylic acid hydrazide (SAH) ensured the selective release of SAH in the acidic inflammatory environment thanks to the pH-sensitive hydrazone bond between the polymer carrier and SAH. The ASA- and SAH-containing nanotherapeutics inhibited both cyclooxygenase isoforms and/or the production of pro-inflammatory mediators. Thanks to their favorable design, they can preferentially accumulate in the inflamed tissue, resulting in reduced side effects and lower dosage, and thus more effective and safer treatment.
- MeSH
- Acrylamides chemistry pharmacology administration & dosage MeSH
- Anti-Inflammatory Agents pharmacology administration & dosage chemistry MeSH
- Aspirin * administration & dosage pharmacology chemistry MeSH
- Prostaglandin-Endoperoxide Synthases metabolism MeSH
- Cyclooxygenase Inhibitors pharmacology administration & dosage chemistry MeSH
- Delayed-Action Preparations * MeSH
- Inflammation Mediators metabolism MeSH
- Mice MeSH
- Nanoparticles * chemistry MeSH
- Drug Carriers chemistry MeSH
- Polymers * chemistry administration & dosage MeSH
- Drug Liberation MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
MicroRNA hsa-miR-29 was connected to a number of malignancies. Its target genes are many, among them Mcl-1 that is expressed in three possible isoforms, one of which is anti-apoptotic and another one pro-apoptotic. Ratio of these two isoforms appears to affect cell response to external stimuli. We have demonstrated that miR-29b enhanced etoposide toxicity in HeLa cell line by modulating this ratio of Mcl-1 isoforms. However, it is not known whether the described miR-29 effect is common to various cancer types or even have the opposite effect. This represents a significant problem for possible future applications. In this report, we demonstrate that miR-29b affects toxicity of 60 μM etoposide in cell lines derived from selected malignancies. The mechanism, however, differs among the cell lines tested. Hep G2 cells demonstrated similar effect of miR-29b on etoposide toxicity as was described in HeLa cells, i.e. modulation of Mcl-1 expression. Target protein down-regulated by miR-29b resulting in enhanced etoposide toxicity in Caco-2 cells was, however, Bcl-2 protein. Moreover, H9c2, Hek-293 and ARPE-19 cell lines selected as a representatives of non-malignant cells, showed no effect of miR-29b on etoposide toxicity. Our data suggest that miR-29b could be a common enhancer of etoposide toxicity in malignant cells due to its modulation of Bcl family proteins.
- MeSH
- Apoptosis drug effects genetics MeSH
- Hep G2 Cells MeSH
- Caco-2 Cells MeSH
- Etoposide * toxicity pharmacology MeSH
- Antineoplastic Agents, Phytogenic pharmacology toxicity MeSH
- HEK293 Cells MeSH
- HeLa Cells MeSH
- Humans MeSH
- MicroRNAs * genetics metabolism MeSH
- Myeloid Cell Leukemia Sequence 1 Protein * genetics metabolism MeSH
- Proto-Oncogene Proteins c-bcl-2 genetics metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
AlphaFold is an artificial intelligence approach for predicting the three-dimensional (3D) structures of proteins with atomic accuracy. One challenge that limits the use of AlphaFold models for drug discovery is the correct prediction of folding in the absence of ligands and cofactors, which compromises their direct use. We have previously described the optimization and use of the histone deacetylase 11 (HDAC11) AlphaFold model for the docking of selective inhibitors such as FT895 and SIS17. Based on the predicted binding mode of FT895 in the optimized HDAC11 AlphaFold model, a new scaffold for HDAC11 inhibitors was designed, and the resulting compounds were tested in vitro against various HDAC isoforms. Compound 5a proved to be the most active compound with an IC50 of 365 nM and was able to selectively inhibit HDAC11. Furthermore, docking of 5a showed a binding mode comparable to FT895 but could not adopt any reasonable poses in other HDAC isoforms. We further supported the docking results with molecular dynamics simulations that confirmed the predicted binding mode. 5a also showed promising activity with an EC50 of 3.6 μM on neuroblastoma cells.
- MeSH
- Histone Deacetylases * metabolism MeSH
- Histone Deacetylase Inhibitors * pharmacology chemistry chemical synthesis MeSH
- Humans MeSH
- Molecular Structure MeSH
- Cell Line, Tumor MeSH
- Neuroblastoma * drug therapy pathology MeSH
- Antineoplastic Agents * pharmacology chemistry chemical synthesis MeSH
- Drug Design * MeSH
- Molecular Dynamics Simulation MeSH
- Molecular Docking Simulation MeSH
- Artificial Intelligence MeSH
- Dose-Response Relationship, Drug MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Enzyme activity is regulated by several mechanisms, including phosphorylation. Phosphorylation is a key signal transduction process in all eukaryotic cells and is thus crucial for virtually all cellular processes. In addition to its direct effect on protein structure, phosphorylation also affects protein-protein interactions, such as binding to scaffolding 14-3-3 proteins, which selectively recognize phosphorylated motifs. These interactions then modulate the catalytic activity, cellular localisation and interactions of phosphorylated enzymes through different mechanisms. The aim of this mini-review is to highlight several examples of 14-3-3 protein-dependent mechanisms of enzyme regulation previously studied in our laboratory over the past decade. More specifically, we address here the regulation of the human enzymes ubiquitin ligase Nedd4-2, procaspase-2, calcium-calmodulin dependent kinases CaMKK1/2, and death-associated protein kinase 2 (DAPK2) and yeast neutral trehalase Nth1.
- MeSH
- Phosphorylation MeSH
- Humans MeSH
- 14-3-3 Proteins * metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
TGFβ has roles in inflammation, wound healing, epithelial to mesenchymal transition (EMT), and cancer stem cell states, and acts as a tumor suppressor gene for squamous cell carcinoma (SCC). SCCs are also characterized by high levels of ΔNp63, which induces epithelial cell phenotypes and maintains squamous stem cells. Previous studies indicate a complex interplay between ΔNp63 and TGFβ signaling, with contradictory effects reported. We investigated the effects of TGFβ on p63 isoform proteins and mRNAs in non-malignant squamous and SCC cells, and the role of either canonical or non-canonical TGFβ signaling pathways. TGFβ selectively increased ΔNp63 protein levels in non-malignant keratinocytes in association with SMAD3 activation and was prevented by TGFβ receptor inhibition, indicating activation of canonical TGFβ pathway signaling. TP63 isoform mRNAs showed discordance from protein levels, with an initial increase in both TAP63 and ΔNP63 mRNAs followed by a decrease at later times. These data demonstrate complex and heterogeneous effects of TGFβ in squamous cells that depend on the extent of canonical TGFβ pathway aberrations. The interplay between TGFβ and p63 is likely to influence the magnitude of EMT states in SCC, with clinical implications for tumor progression and response to therapy.
Anthracyclines, such as doxorubicin (adriamycin), daunorubicin, or epirubicin, rank among the most effective agents in classical anticancer chemotherapy. However, cardiotoxicity remains the main limitation of their clinical use. Topoisomerase IIβ has recently been identified as a plausible target of anthracyclines in cardiomyocytes. We examined the putative topoisomerase IIβ selective agent XK469 as a potential cardioprotective and designed several new analogs. In our experiments, XK469 inhibited both topoisomerase isoforms (α and β) and did not induce topoisomerase II covalent complexes in isolated cardiomyocytes and HL-60, but induced proteasomal degradation of topoisomerase II in these cell types. The cardioprotective potential of XK469 was studied on rat neonatal cardiomyocytes, where dexrazoxane (ICRF-187), the only clinically approved cardioprotective, was effective. Initially, XK469 prevented daunorubicin-induced toxicity and p53 phosphorylation in cardiomyocytes. However, it only partially prevented the phosphorylation of H2AX and did not affect DNA damage measured by Comet Assay. It also did not compromise the daunorubicin antiproliferative effect in HL-60 leukemic cells. When administered to rabbits to evaluate its cardioprotective potential in vivo, XK469 failed to prevent the daunorubicin-induced cardiac toxicity in either acute or chronic settings. In the following in vitro analysis, we found that prolonged and continuous exposure of rat neonatal cardiomyocytes to XK469 led to significant toxicity. In conclusion, this study provides important evidence on the effects of XK469 and its combination with daunorubicin in clinically relevant doses in cardiomyocytes. Despite its promising characteristics, long-term treatments and in vivo experiments have not confirmed its cardioprotective potential.
- MeSH
- Anthracyclines * toxicity therapeutic use MeSH
- Quinoxalines * MeSH
- Daunorubicin toxicity therapeutic use MeSH
- DNA Topoisomerases, Type II metabolism therapeutic use MeSH
- Doxorubicin toxicity MeSH
- Topoisomerase II Inhibitors * toxicity therapeutic use MeSH
- Cardiotoxicity MeSH
- Rabbits MeSH
- Rats MeSH
- DNA Damage MeSH
- Antibiotics, Antineoplastic toxicity MeSH
- Animals MeSH
- Check Tag
- Rabbits MeSH
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
HDAC11 is a class IV histone deacylase with no crystal structure reported so far. The catalytic domain of HDAC11 shares low sequence identity with other HDAC isoforms, which makes conventional homology modeling less reliable. AlphaFold is a machine learning approach that can predict the 3D structure of proteins with high accuracy even in absence of similar structures. However, the fact that AlphaFold models are predicted in the absence of small molecules and ions/cofactors complicates their utilization for drug design. Previously, we optimized an HDAC11 AlphaFold model by adding the catalytic zinc ion and minimization in the presence of reported HDAC11 inhibitors. In the current study, we implement a comparative structure-based virtual screening approach utilizing the previously optimized HDAC11 AlphaFold model to identify novel and selective HDAC11 inhibitors. The stepwise virtual screening approach was successful in identifying a hit that was subsequently tested using an in vitro enzymatic assay. The hit compound showed an IC50 value of 3.5 μM for HDAC11 and could selectively inhibit HDAC11 over other HDAC subtypes at 10 μM concentration. In addition, we carried out molecular dynamics simulations to further confirm the binding hypothesis obtained by the docking study. These results reinforce the previously presented AlphaFold optimization approach and confirm the applicability of AlphaFold models in the search for novel inhibitors for drug discovery.
