Peptidomimetic Small-Molecule Inhibitors of 3CLPro Activity and Spike-ACE2 Interaction: Toward Dual-Action Molecules against Coronavirus Infections

The development of molecules able to target protein-protein interactions (PPIs) is of interest for the development of novel therapeutic agents. Since a high percentage of PPIs are mediated by α-helical structure at the interacting surface, peptidomimetics that reproduce the essential conformational components of helices are useful templates for the development of PPIs inhibitors. In this work, the synthesis of a constrained dipeptide isostere and insertion in the short peptide epitope EDLFYQ of the angiotensin-converting enzyme 2 (ACE2) α1 helix domain resulted in the identification of a molecule capable of inhibiting the SARS-CoV-2 ACE2/spike interaction in the micromolar range. Moreover, inhibition of SARS-CoV-2 3CLPro main protease activity was assessed as an additional inhibitory property of the synthesized peptidomimetics, taking advantage of the C-terminal Q amino acid present in both the ACE2 epitope and the Mpro recognizing motif (APSTVxLQ), thus paving the way to the development of multitarget therapeutics toward coronavirus infections.

Response Predictive Markers and Synergistic Agents for Drug Repositioning of Statins in Ovarian Cancer

In the field of drug repurposing, the use of statins for treating dyslipidemia is considered promising in ovarian cancer treatment based on epidemiological studies and basic research findings. Biomarkers should be established to identify patients who will respond to statin treatment to achieve clinical application. In the present study, we demonstrated that statins have a multifaceted mode of action in ovarian cancer and involve pathways other than protein prenylation. To identify biomarkers that predict the response to statins, we subjected ovarian cancer cells to microarray analysis and calculated Pearson’s correlation coefficients between gene expression and cell survival after statin treatment. The results showed that VDAC1 and LDLRAP1 were positively and negatively correlated with the response to statins, respectively. Histoculture drug response assays revealed that statins were effective in clinical samples. We also confirmed the synergistic effects of statins with paclitaxel and panobinostat and determined that statins are hematologically safe to administer to statin-treated mice. Future clinical trials based on the expression of the biomarkers identified in this study for repurposing statins for ovarian cancer treatment are warranted.

Design, Synthesis and Biological Evaluation of Novel Piperazinone Derivatives as Cytotoxic Agents

Purpose: In this study, a series of piperazin-2-one derivatives were prepared through bioisosteric substitution of the imidazole ring of L-778,123 (imidazole-containing FTase inhibitor) and rearrangement of groups based on the tipifarnib structure. Final compounds were evaluated for their cytotoxic activities on cancer and normal cell lines by MTT assay. Methods: Methyl α-bromophenylacetic acid and 1-(3-chlorophenyl) piperazin-2-one were synthesized using previously described methods. Methyl 2-(4-chlorophenyl)-2-(4-(3- chlorophenyl)-3-oxopiperazin-1-yl) acetate was prepared by reaction between these two compounds in presence of potassium carbonate. Finally, methoxy group of ester was substituted by various amines such as guanidine, thiourea, urea and hydrazide. The synthesized compounds were tested for their cytotoxicity against colon cancer (HT-29) and lung cancer (A549) cell lines as well as MRC-5 (normal fetal lung fibroblasts) cells as a healthy cell line using MTT colorimetric assay method. Results: Replacement of imidazole moiety with guanidine, thiourea, and hydrazide could increase cytotoxicity toward all three cell lines. Some substituents, such as amine, urea, and hydroxylamine exhibited significant cytotoxicity (<500 µM) but lower than L-778,123 as standard compound. Hydroxyl and methoxy substituents did not show significant cytotoxicity. Imidazole substituent group revealed cytotoxicity similar to L-778,123 All compounds showed lower cytotoxic activity against normal cell lines compared with cancer cell lines. Conclusion: It seems the electron density of substituted groups and rearrangement of groups may significantly increase cytotoxic activity.

Synthesis of glycolurils and their analogues

Glycolurils — tetrahydroimidazo[4,5-d]imidazole-2,5(1H,3H)-diones — have found widespread applications in various fields of science and technology. Among them, there are pharmacologically active compounds (antibacterial, nootropic, neurotropic agents, etc.), explosives, gelators, etc. They are used as building blocks in supramolecular chemistry. Therefore, the development of new methods for the synthesis of glycolurils and their analogues has constantly attracted the attention of researchers. In this review, we analyze various approaches to the synthesis of glycolurils and their analogues. The review covers both classical reactions of ureas and related compounds with α-dicarbonyl compounds or with 4,5-dihydroxyimida-zolidin-2-ones (-thiones) and their imino analogues and new original reactions of 4,5-dihydroxyimidazolidin-2-ones (-thiones), imidazolinones and their bicyclic analogues with ureas and KNCS in the presence of acids, condensations of 1,4-disubstituted 1,4-diaza-1,3-dienes with isocyanic and/or isothiocyanic acids or isocyanates, triazine ring contraction in imidazotriazines to give the imidazolidine ring, and transformations of urazoles.

The bibliography includes 129 references.

Synthesis and Cytotoxicity Evaluation of Some Novel 1-(3-Chlorophenyl)piperazin-2-one Derivatives Bearing Imidazole Bioisosteres

A series of substituted 3-chlorophenylpiperazinone derivatives were synthesised using L-778123 (an imidazole-containing FTase inhibitor) as a model by bioisosteric replacement of the imidazole ring. The final compounds were evaluated against two human cancer cell lines including A549 (lung cancer) and HT-29 (colon cancer) by MTT assay. The results showed that substitution of imidazole ring with 1-amidinourea, semicarbazide, and thiobiuret led to improvement of cytotoxic activity against both cell lines.