Design and synthesis of quinazolin-4-one derivatives as potential anticancer agents and investigation of their interaction with RecQ helicases.

The upregulation of RecQ helicases has been associated with cancer cell survival and resistance to chemotherapy, making them appealing targets for therapeutic intervention. In this study, twenty-nine novel quinazolinone derivatives were designed and synthesized. The anti-proliferative activity of all compounds was evaluated against 60 cancer cell lines at the National Cancer Institute Developmental Therapeutic Program, with six compounds (11f, 11g, 11k, 11n, 11p, and 11q) being promoted to a five-dose screen. Compound 11g demonstrated high cytotoxic activity against all examined cell lines. The compounds were further assayed for Bloom syndrome (BLM) helicase inhibition, where 11g, 11q, and 11u showed moderate activity. These compounds were counter-screened against WRN and RECQ1 helicases, where 11g moderately inhibited both enzymes. An ATP competition assay confirmed that the compounds bound to the ATP site of RecQ helicases, and molecular docking simulations were used to study the binding mode within the active site of BLM, WRN, and RECQ1 helicases. Compound 11g induced apoptosis in both HCT-116 and MDA-MB-231 cell lines, but also caused an G2/M phase cell cycle arrest in HCT-116 cells. This data revealed the potential of 11g as a modulator of cell cycle dynamics and supports its interaction with RecQ helicases. In addition, compound 11g displayed non-significant toxicity against FCH normal colon cells at doses up to 100 µM, which confirming its high safety margin and selectivity on cancer cells. Overall, these findings suggest compound 11g as a potential pan RecQ helicase inhibitor with high anticancer potency and a favorable safety margin and selectivity.

Terminators or Guardians? Design, Synthesis, and Cytotoxicity Profiling of Chalcone-Sulfonamide Hybrids.

With a "less is more" philosophy, a series of 15 chalcone-sulfonamide hybrids were designed anticipating synergistic anticancer activity. The aromatic sulfonamide moiety was included as a known direct inhibitor of carbonic anhydrase IX activity through its zinc chelating property. The chalcone moiety was incorporated as an electrophilic stressor to indirectly inhibit carbonic anhydrase IX cellular activity. Screening by the Developmental Therapeutics Program of the National Cancer Institute, NCI-60, revealed that 12 derivatives were potent inhibitors of cancer cell growth in multiple cell lines and were promoted to the five-dose screen. The cancer cell growth inhibition profile indicated sub- to two-digit micromolar potency (GI50 down to 0.3 µM and LC50 as low as 4 µM) against colorectal carcinoma cells, in particular. Unexpectedly, most compounds demonstrated low to moderate potency as direct inhibitors of carbonic anhydrase catalytic activity in vitro, with 4d being the most potent, having an average Ki value of 4 µM. Compound 4j showed ca. six-fold selectivity to carbonic anhydrase IX over the other tested isoforms in vitro. Cytotoxicity of both 4d and 4j in live HCT116, U251, and LOX IMVI cells under hypoxic conditions confirmed their targeting of carbonic anhydrase activity. Elevation of oxidative cellular stress was stipulated from the increase in Nrf2 and ROS levels in 4j-treated colorectal carcinoma, HCT116, cells compared to the control. Compound 4j arrested the cell cycle of HCT116 cells at the G1/S phase. In addition, both 4d and 4j showed up to 50-fold cancer cell selectivity compared to the non-cancerous HEK293T cells. Accordingly, this study presents 4d and 4j being new, synthetically accessible, simplistically designed derivatives as potential candidates to be further developed as anticancer therapeutics.

Isonicotinic acid N-oxide, from isoniazid biotransformation by Aspergillus niger, as an InhA inhibitor antituberculous agent against multiple and extensively resistant strains supported by in silico docking and ADME prediction.

Biotransformation of isoniazid produced isonicotinic acid (1), isonicotinic acid N-oxide (2), and isonicotinamide (3) which were isolated by column chromatography using silica gel and Sephadex LH 20 and elucidated using various spectroscopies. This is the first report for isolation of 2. Antituberculosis activity was evaluated against Mycobacterium tuberculosis strains: drug sensitive (DS), multiple drug resistant (MDR) and extensively drug resistant (XDR). 1-3 and isoniazid showed MICs of 63.49, 0.22, 15.98 and 0.88 µM, respectively, against the DS strain. For the MDR strain, 2 and 3 exhibited MICs of 28.06 and > 1000 µM, respectively, while 1 was inactive. Moreover, 2 had an MIC of 56.19 µM against XDR strain, while 1 and 3 were inactive. Docking simulation using enoyl ACP reductase (InhA) revealed favorable protein-ligand interactions. In silico study of pharmacokinetics and hepatotoxicity predicted 1-3 to have good oral bioavailability and 2 to have a lower hepatoxicity probability than isoniazid.

Prospective Antiviral Effect of Ulva lactuca Aqueous Extract against COVID-19 Infection.

Marine algal extracts exhibit a potent inhibitory effect against several enveloped and non-enveloped viruses. The infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has several adverse effects, including an increased mortality rate. The anti-COVID-19 agents are still limited; this issue requires exploring novel, effective anti-SARS-CoV-2 therapeutic approaches. This study investigated the antiviral activity of an aqueous extract of Ulva lactuca, which was collected from the Gulf of Suez, Egypt. The aqueous extract of Ulva lactuca was characterized by high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Energy Dispersive X-ray (EDX) analyses. According to the HPLC analysis, the extract comprises several sugars, mostly rhamnose (32.88%). The FTIR spectra showed numerous bands related to the functional groups. EDX analysis confirmed the presence of different elements, such as oxygen (O), carbon (C), sulfur (S), magnesium (Mg), potassium (K), calcium (Ca), and sodium (Na), with different concentrations. The aqueous extract of U. lactuca (0.0312 mg/mL) exhibited potent anti-SARS-CoV-2 activity via virucidal activity, inhibition of viral replication, and interference with viral adsorption (% inhibitions of 64%, 33.3%, and 31.1%, respectively). Consequently, ulvan could be a promising compound for preclinical study in the drug development process to combat SARS-CoV-2.

In Vitro Characterization of Inhibitors for Lung A549 and Leukemia K562 Cell Lines from Fungal Transformation of Arecoline Supported by In Silico Docking to M3-mAChR and ADME Prediction.

The search for anticancer drugs is of continuous interest. Arecoline is an alkaloid with anticancer activity. Herein, the metabolism of arecoline through fungal transformation was investigated for the discovery of potential anticancer drugs with higher activity and selectivity. Compounds 1-5 were isolated, and their structures were fully elucidated using various spectroscopic analyses, including 1D and 2D NMR, ESIMS, and HRESIMS. This is the first report for the isolation of compounds 1 and 2. An MTT assay was performed to determine the cytotoxic activity of arecoline and its metabolites in vitro using non-small-cell lung cancer A549 and leukemia K562 cell lines compared to staurosporine and doxorubicin as positive controls. For the non-small-cell lung A549 cell line, arecoline hydrobromide, staurosporine, and doxorubicin resulted in IC50 values of 11.73 ± 0.71 µM, 10.47 ± 0.64 µM, and 5.05 ± 0.13 µM, respectively, while compounds 1, 3, and 5 exhibited IC50 values of 3.08 ± 0.19 µM, 7.33 ± 0.45 µM, and 3.29 ± 0.20 µM, respectively. For the leukemia K562 cell line, the IC50 values of arecoline hydrobromide, staurosporine, and doxorubicin were 15.3 ± 1.08 µM, 5.07 ± 0.36 µM, and 6.94 ± 0.21 µM, respectively, while the IC50 values of compounds 1, 3 and 5 were 1.56 ± 0.11 µM, 3.33 ± 0.24 µM, and 2.15 ± 0.15 µM, respectively. The selectivity index value of these compounds was higher than 3. These results indicated that compounds 1, 3, and 5 are very strong cytotoxic agents with higher activity than the positive controls and good selectivity toward the tested cancer cell lines. Cell cycle arrest was then studied by flow cytometry to investigate the apoptotic mechanism. Docking simulation revealed that most compounds possessed good binding poses and favorable protein-ligand interactions with muscarinic acetylcholine receptor M3-mAChR protein. In silico study of pharmacokinetics using SwissADME predicted compounds 1-5 to be drug-like with a high probability of good oral bioavailability.

Nicotinonitrile-derived apoptotic inducers: Design, synthesis, X-ray crystal structure and Pim kinase inhibition.

Although a plethora of targeted anticancer small molecule drugs became available, the low response rate and drug resistance imply the continuous need for expanding the anticancer chemical space. In this study, a novel series of nicotinonitrile derivatives was designed, synthesized and evaluated for cytotoxic activities in HepG2 and MCF-7 cells. All derivatives showed high to moderate cytotoxic activity against both cell lines, with cell-type and chemotype-dependent cytotoxic potential. The normal HEK-293 T cells were ca. 50-fold less susceptible to the cytotoxic effect of the inhibitors. The in vitro enzyme inhibitory activity of selected active cytotoxic derivatives 8c, 8e, 9a, 9e and 12 showed that they have sub- to one digit micromolar 50 % inhibitory concentration (IC50) against the three Pim kinase isoforms, with 8e being the most potent (IC50 ≤ 0.28 µM against three Pim kinases), comparable to the pan kinase inhibitor, Staurosporine. In HepG2, 8e induced cell cycle arrest at the G2/M phase. Apoptotic mechanistic studies with 8c and 8e in HepG2 cells, indicated a significant upregulation in both P53 and caspase-3 relative gene expression, as well as increased Bax/Bcl-2 protein expression level. Further, docking studies combined with molecular dynamic simulation showed a stable complex with high binding affinity of 8e to Pim-1 kinase; exploiting a negative electrostatic potential surface interaction with the added dimethyl amino group in the new compounds. Moreover, in silico ADME profile prediction indicated that all compounds are orally bioavailable and most of them can penetrate the blood-brain barrier. This study presents novel nicotinonitrile derivatives as auspicious hits for further optimization as antiproliferative agents against liver cancer cells and promising pan Pim kinase inhibitors at submicromolar concentrations.

Correction to Design, Synthesis, and Biological Evaluation of Tetrahydroisoquinoline-Based Histone Deacetylase 8 Selective Inhibitors.

[This corrects the article DOI: 10.1021/acsmedchemlett.7b00126.].

Structurally Diverse Histone Deacetylase Photoreactive Probes: Design, Synthesis, and Photolabeling Studies in Live Cells and Tissue.

Histone deacetylase (HDAC) activity is modulated in vivo by post-translational modifications and formation of multiprotein complexes. Novel chemical tools to study how these factors affect engagement of HDAC isoforms by HDAC inhibitors (HDACi) in cells and tissues are needed. In this study, a synthetic strategy to access chemically diverse photoreactive probes (PRPs) was developed and used to prepare seven novel HDAC PRPs 9-15. The class I HDAC isoform engagement by PRPs was determined in biochemical assays and photolabeling experiments in live SET-2, HepG2, HuH7, and HEK293T cell lines and in mouse liver tissue. Unlike the HDAC protein abundance and biochemical activity against recombinant HDACs, the chemotype of the PRPs and the type of cells were key in defining the engagement of HDAC isoforms in live cells. Our findings suggest that engagement of HDAC isoforms by HDACi in vivo may be substantially modulated in a cell- and tissue-type-dependent manner.

Scaffold dependent histone deacetylase (HDAC) inhibitor induced re-equilibration of the subcellular localization and post-translational modification state of class I HDACs.

The mechanism of action of histone deacetylase inhibitors (HDACi) is mainly attributed to the inhibition of the deacetylase catalytic activity for their histone substrates. In this study, we analyzed the abundance of class I HDACs in the cytosolic, nuclear soluble and chromatin bound cellular fractions in breast cancer cells after HDACi treatment. We found that potent N-hydroxy propenamide-based HDACi induced a concentration dependent decrease in the HDAC1 associated with chromatin and a lasting concomitant increase in cytoplasmic HDAC1 while maintaining total protein expression. No such change occurred with HDAC2 or 8, however, an increase in cytoplasmic non-phosphorylated HDAC3 was also observed. The subcellular re-equilibration of HDAC1 was subsequent to the accumulation of acetylated histones and might be cell cycle dependent. This study suggests that the biological activity of a subset of N-hydroxy propenamide-based HDACi may stem from direct competition with histone substrates of HDACs as well as from spatial separation from their substrates in the nucleus and/or change in post-translational modification status of HDACs.

Divergent JNK Phosphorylation of HDAC3 in Triple-Negative Breast Cancer Cells Determines HDAC Inhibitor Binding and Selectivity.

Histone deacetylase (HDAC) catalytic activity is regulated by formation of co-regulator complexes and post-translational modification. Whether these mechanisms are transformed in cancer and how this affects the binding and selectivity of HDAC inhibitors (HDACis) is unclear. In this study, we developed a method that identified a 3- to 16-fold increase in HDACi selectivity for HDAC3 in triple-negative breast cancer (TNBC) cells in comparison with luminal subtypes that was not predicted by current practice measurements with recombinant proteins. We found this increase was caused by c-Jun N-terminal kinase (JNK) phosphorylation of HDAC3, was independent of HDAC3 complex composition or subcellular localization, and was associated with a 5-fold increase in HDAC3 enzymatic activity. This study points to HDAC3 and the JNK axes as targets in TNBC, highlights how HDAC phosphorylation affects HDACi binding and selectivity, and outlines a method to identify changes in individual HDAC isoforms catalytic activity, applicable to any disease state.

Design, Synthesis, and Biological Evaluation of Tetrahydroisoquinoline-Based Histone Deacetylase 8 Selective Inhibitors.

Histone deacetylase 8 (HDAC8) is a promising drug target for multiple therapeutic applications. Here, we describe the modeling, design, synthesis, and biological evaluation of a novel series of C1-substituted tetrahydroisoquinoline (TIQ)-based HDAC8 inhibitors. Minimization of entropic loss upon ligand binding and use of the unique HDAC8 "open" conformation of the binding site yielded a successful strategy for improvement of both HDAC8 potency and selectivity. The TIQ-based 3g and 3n exhibited the highest 82 and 55 nM HDAC8 potency and 330- and 135-fold selectivity over HDAC1, respectively. Selectivity over other class I isoforms was comparable or better, whereas inhibition of HDAC6, a class II HDAC isoform, was below 50% at 10 µM. The cytotoxicity of 3g and 3n was evaluated in neuroblastoma cell lines, and 3n displayed concentration-dependent cytotoxicity similar to or better than that of PCI-34051. The selectivity of 3g and 3n was confirmed in SH-SY5Y cells as both did not increase the acetylation of histone H3 and α-tubulin. Discovery of the novel TIQ chemotype paves the way for the development of HDAC8 selective inhibitors for therapeutic applications.