Correction: Saadeh et al. Recent Advances in the Synthesis and Biological Activity of 8-Hydroxyquinolines. Molecules 2020, 25, 4321.

The author wishes to make the following correction to this paper [...].

Evaluation of crotamine based probes as intracellular targeted contrast agents for magnetic resonance imaging.

Crotamine is a lysine and cysteine rich 42 amino acids long bio-active polypeptide, isolated from the venom of a South American rattlesnake, that can also be used as cell penetrating peptide. A facile synthetic scheme for coupling cargo molecules like fluorophores (carboxyfluorescein) or MRI probes (Gd-DO3A-based macrocycle) is presented. The toxicity, cellular internalization and steady-state accumulation after long-term incubation for 18 h, as well as magnetic resonance relaxivities and cellular relaxation rates of crotamine based probes were evaluated and compared to its shorter synthetic fragment CyLoP-1. The longitudinal relaxivity (r1) of the conjugates of CyLoP-1 and crotamine is significantly lower in medium than in water indicating to the lower contrast enhancement efficacy of DO3A-based probes in biological samples. Carboxyfluorescein labeled crotamine did not exhibit toxicity up to a concentration of 2.5 µM. CyLoP-1 accumulated about four times better within the cells compared to crotamine. Fluorescence microscopy suggests different predominant uptake mechanisms for crotamine and CyLoP-1 in 3T3 cells. While crotamine is predominantly localized in vesicular structures (most likely endosomes and lysosomes) within the cell, CyLoP-1 is mainly homogeneously distributed in the cytosol. The cellular relaxation rate (R1, cell) of the crotamine based probe was not significantly increased whereas the corresponding CyLoP-1-derivative showed a slightly elevated R1, cell. This study indicates the potential of crotamine and in particular the shorter fragment CyLoP-1 to be useful for an efficient transmembrane delivery of agents directed to intracellular (cytosolic) targets. However, the applicability of the conjugates synthesized here as contrast agents in MR imaging is limited. Further improvement is needed to prepare more efficient probes for MRI applications, i.e., by replacing the DO3A- with a DOTA-based chelate.

Design, Synthesis, and Biological Evaluation of Novel MAO-A Inhibitors Targeting Lung Cancer.

Lung cancer is one of the most common causes of cancer-related deaths worldwide. Monoamine Oxidase-A (MAO-A) enzyme mediates the production of reactive oxygen species (ROS) that trigger DNA damage and oxidative injury of cells resulting in tumor initiation and progression. Available MAO-A inhibitors are used as antidepressants, however, their role as anticancer agents is still under investigation. Ligand- and structure-based drug design approaches guided the discovery and development of novel MAO-A inhibitors. A series of 1H indole-2-carboxamide derivatives was prepared and characterized using 1H-NMR, 13C-NMR, and IR. The antiproliferative effects of MAO-A inhibitors were evaluated using the cell viability assay (MTT), and MAO-A activity was evaluated using MAO-A activity assay. The presumed inhibitors significantly inhibited the growth of lung cell lines in a dose- and time dependent manner. The half maximal inhibitory concentration (IC50) values of MAO-A inhibitors (S1, S2, S4, S7, and S10) were 33.37, 146.1, 208.99, 307.7, and 147.2 µM, respectively, in A549. Glide docking against MAO-A showed that the derivatives accommodate MAO-A binding cleft and engage with key binding residues. MAO-A inhibitors provide significant and consistent evidence on MAO-A activity in lung cancer and present a potential target for the development of new chemotherapeutic agents.

Synthesis and In Vivo Hypolipidemic Effect of Some N-(Benzoylphenyl)-Carboxamide Derivatives in Triton WR-1339-Induced Hyperlipidemic Rats

A series of N-(benzoylphenyl)-carboxamide derivatives (2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a and 6b) was prepared with good yields by reacting the corresponding carbonyl chlorides with aminobenzophenones at room temperature. This was followed by evaluating the hypotriglyceridemic and hypocholesterolemic effects of 3b, 5a and 5b. Triton WR-1339 (300 mg/kg) was intraperitoneally administered to overnight-fasted rats to induce hyperlipidemia. Rats were divided into six groups: control, hyperlipidemic, hyperlipidemic plus compounds 3b, 5a and 5b and hyperlipidemic plus bezafibrate. Results showed that after 18 h of treatment at a dose of 15 mg/kg body weight of each of the test compounds, the elevated plasma levels of triglycerides (TG) and total cholesterol (TC) were significantly lowered by compounds 5b and 3b (p < 0.001) and by 5a (p < 0.0001), compared to the hyperlipidemic control group. Compounds 3b and 5a significantly increased levels of high-density lipoprotein cholesterol (HDL-C) by 58 and 71%, respectively. In addition, compounds 3b and 5a caused significant reduction (p < 0.0001) of low-density lipoprotein cholesterol (LDL-C) levels compared to the control group. These results suggest a promising potential for compounds 3b, 5a and 5b as lipid-lowering agents, which may contribute to reducing the risk of atherosclerosis and cardiovascular disease

Evaluation of crotamine based probes as intracellular targeted contrast agents for magnetic resonance imaging

Crotamine is a lysine and cysteine rich 42 amino acids long bio-active polypeptide, isolated from the venom of a South American rattlesnake, that can also be used as cell penetrating peptide. A facile synthetic scheme for coupling cargo molecules like fluorophores (carboxyfluorescein) or MRI probes (Gd-DO3A-based macrocycle) is presented. The toxicity, cellular internalization and steady-state accumulation after long-term incubation for 18 h, as well as magnetic resonance relaxivities and cellular relaxation rates of crotamine based probes were evaluated and compared to its shorter synthetic fragment CyLoP-1. The longitudinal relaxivity (r1) of the conjugates of CyLoP-1 and crotamine is significantly lower in medium than in water indicating to the lower contrast enhancement efficacy of DO3A-based probes in biological samples. Carboxyfluorescein labeled crotamine did not exhibit toxicity up to a concentration of 2.5 µM. CyLoP-1 accumulated about four times better within the cells compared to crotamine. Fluorescence microscopy suggests different predominant uptake mechanisms for crotamine and CyLoP-1 in 3T3 cells. While crotamine is predominantly localized in vesicular structures (most likely endosomes and lysosomes) within the cell, CyLoP-1 is mainly homogeneously distributed in the cytosol. The cellular relaxation rate (R1, cell) of the crotamine based probe was not significantly increased whereas the corresponding CyLoP-1-derivative showed a slightly elevated R1, cell. This study indicates the potential of crotamine and in particular the shorter fragment CyLoP-1 to be useful for an efficient transmembrane delivery of agents directed to intracellular (cytosolic) targets. However, the applicability of the conjugates synthesized here as contrast agents in MR imaging is limited. Further improvement is needed to prepare more efficient probes for MRI applications, i.e., by replacing the DO3A- with a DOTA-based chelate.

New derivatives of sulfonylhydrazone as potential antitumor agents: Design, synthesis and cheminformatics evaluation.

Phosphoinositide 3-kinase α (PI3Kα) is a propitious target for designing anticancer drugs. A series of new N'-(diphenylmethylene)benzenesulfonohydrazide was synthesized and characterized using FT-IR, NMR (1H and 13C), HRMS, and elemental analysis. Target compounds exhibited an antiproliferative effect against the human colon carcinoma (HCT-116) cell line. Our cheminformatics analysis indicated that the para-tailored derivatives [p-NO2 (3) and p-CF3 (7)] have better ionization potentials based on calculated Moran autocorrelations and ionization potentials. Subsequent in vitro cell proliferation assays validated our cheminformatics results by providing experimental evidence that both derivatives 3 and 7 exhibited improved antiproliferative activities against HCT-116. Hence, our results emphasized the importance of electron-withdrawing groups and hydrogen bond-acceptors in the rational design of small-molecule chemical ligands targeting PI3Kα. These results agreed with the induced-fit docking against PI3Kα, highlighting the role of p-substituted aromatic rings in guiding the ligand-PI3Kα complex formation, by targeting a hydrophobic pocket in the ligand-binding site and forming π-stacking interactions with a nearby tryptophan residue.

An Integrative Informatics Approach to Explain the Mechanism of Action of N1-(Anthraquinon-2-yl) Amidrazones as BCR/ABL Inhibitors.

BACKGROUND: Drugs incorporating heterocyclic chemical skeletons possess a plethora of therapeutic activities such as anticancer, antimicrobial, antihypertensive, and antipsychiatric effects. It is becoming routine, nowadays, to use cheminformatics and bioinformatics methods to elucidate the mechanism(s) of action of such drugs. OBJECTIVE: This study aimed to probe the activity of a recently published series of N1- (anthraquinon-2-yl) amidrazone piperazine derivatives employing computational strategies[1], identify their structural basis of binding to BCR/ABL kinase domain, and explain their anticancer activities in human breast adenocarcinoma (MCF-7) and chronic myelogenous leukemia (K562) cell lines. METHODS: We applied an in silico integrative informatics approach integrating molecular descriptors, docking studies, cheminformatics, and network analysis. RESULTS: Our results highlighted the possible involvement of the BCR/ABL and DRD2 pathways in the anticancer activity of the studied compounds, and induced fit docking (IFD) indicated that the BCR/ABL kinase domain is a putative drug target. Additionally, high-scoring docking poses identified a unique network of hydrogen bonding with amino acids Y253, K271, E286, V299, L301, T315, M318, I360, R362, V379, and D3810. CONCLUSION: Using an integrative informatics approach to characterize our anticancer compounds, we were able to explain the biological differences between synthesized and biologically validated amidrazone piperazine anticancer agents. We were also able to postulate a mechanism of action of this novel group of anticancer agents.

N-Phenyl-6-Chloro-4-Hydroxy-2-Quinolone-3-CarboxAmides: Molecular Docking, Synthesis, and Biological Investigation as Anticancer Agents.

Cancer is a multifactorial disease and the second leading cause of death worldwide. Diverse factors induce carcinogenesis, such as diet, smoking, radiation, and genetic defects. The phosphatidylinositol 3-kinase (PI3Kα) has emerged as an attractive target for anticancer drug design. Eighteen derivatives of N-phenyl-6-chloro-4-hydroxy-2-quinolone-3-carboxamide were synthesized and characterized using FT-IR, NMR (1H and 13C), and high-resolution mass spectra (HRMS). The series exhibited distinct antiproliferative activity (IC50 µM) against human epithelial colorectal adenocarcinoma (Caco-2) and colon carcinoma (HCT-116) cell lines, respectively: compounds 16 (37.4, 8.9 µM), 18 (50.9, 3.3 µM), 19 (17.0, 5.3 µM), and 21 (18.9, 4.9 µM). The induced-fit docking (IFD) studies against PI3Kαs showed that the derivatives occupy the PI3Kα binding site and engage with key binding residues.

Molecular Modeling, Synthesis and Biological Evaluation of N-Phenyl-4-Hydroxy-6-Methyl-2-Quinolone-3-CarboxAmides as Anticancer Agents.

The emergence of phosphatidylinositol 3-kinase (PI3Kα) in cancer development has accentuated its significance as a potential target for anticancer drug design. Twenty one derivatives of N-phenyl-4-hydroxy-6-methyl-2-quinolone-3-carboxamide were synthesized and characterized using NMR (1H and 13C) and HRMS. The derivatives displayed inhibitory activity against human epithelial colorectal adenocarcinoma (Caco-2) and human colon cancer (HCT-116) cell lines: compounds 8 (IC50 Caco-2 = 98 µM, IC50 HCT-116 = 337 µM) and 16 (IC50 Caco-2 = 13 µM, IC50 HCT-116 = 240.2 µM). Results showed that compound 16 significantly affected the gene encoding AKT, BAD, and PI3K. The induced-fit docking (IFD) studies against PI3Kα demonstrated that the scaffold accommodates the kinase domains and forms H-bonds with significant binding residues.

Recent Advances in the Synthesis and Biological Activity of 8-Hydroxyquinolines.

Compounds containing the 8-hydroxyquinoline (8-HQ) 1 nucleus exhibit a wide range of biological activities, including antimicrobial, anticancer, and antifungal effects. The chemistry and biology of this group have attracted the attention of chemists, medicinal chemists, and professionals in health sciences. A number of prescribed drugs incorporate this group, and numerous 8-HQ- based molecules can be used to develop potent lead compounds with good efficacy and low toxicity. This review focusses on the recent advances in the synthesis of 8-HQ derivatives with different pharmacological properties, including anticancer, antiviral, and antibacterial activities. For this purpose, recent relevant references were searched in different known databases and search engines, such as MEDLINE (PubMed), Google Scholar, Science Direct, Scopus, Cochrane, Scientific Information Database (SID), SciFinder, and Institute for Scientific Information (ISI) Web of Knowledge. This review article provides a literature overview of the various synthetic strategies and biological activities of 8-HQ derivatives and covers the recent related literature. Taken together, compounds containing the 8-HQ moiety have huge therapeutic value and can act as potential building blocks for various pharmacologically active scaffolds. In addition, several described compounds in this review could act leads for the development of drugs against numerous diseases including cancer.

Review on Epidermal Growth Factor Receptor (EGFR) Structure, Signaling Pathways, Interactions, and Recent Updates of EGFR Inhibitors.

The epidermal growth factor receptor (EGFR) belongs to the ERBB family of tyrosine kinase receptors. EGFR signaling cascade is a key regulator in cell proliferation, differentiation, division, survival, and cancer development. In this review, the EGFR structure and its mutations, signaling pathway, ligand binding and EGFR dimerization, EGF/EGFR interaction, and the progress in the development of EGFR inhibitors have been explored.

Ligand-Based Drug Design: Synthesis and Biological Evaluation of Substituted Benzoin Derivatives as Potential Antitumor Agents.

BACKGROUND: Phosphoinositide 3-kinase α (PI3Kα) has emerged as a promising target for anticancer drug design. OBJECTIVES: Target compounds were designed to investigate the effect of the p-OCH3 motifs on ligand/PI3Kα complex interaction and antiproliferative activity. METHODS: Synthesis of the proposed compounds, biological examination tests against human colon adenocarcinoma (HCT-116), breast adenocarcinoma (MCF-7), and breast carcinoma (T47D) cell lines, along with Glide docking studies. RESULTS: A series of 1,2-bis(4-methoxyphenyl)-2-oxoethyl benzoates was synthesized and characterized by means of FT-IR, 1H and 13C NMR, and by elemental analysis. Biological investigation demonstrated that the newly synthesized compounds exhibit antiproliferative activity in human colon adenocarcinoma (HCT-116), breast adenocarcinoma (MCF-7), and breast carcinoma (T47D) cell lines possibly via inhibition of PI3Kα and estrogen receptor alpha (ERα). Additionally, results revealed that these compounds exert selective inhibitory activity, induce apoptosis, and suppress VEGF production. Compound 3c exhibited promising antiproliferative activity in HCT-116 interrogating that hydrogen bond-acceptor mediates ligand/PI3Kα complex formation on m- position. Compounds 3e and 3i displayed high inhibitory activity in MCF-7 and T47D implying a wide cleft discloses the o-attachment. Furthermore, compound 3g exerted selective inhibitory activity against T47D. Glide docking studies against PI3Kα and ERα demonstrated that the series accommodate binding to PI3Kα and/or ERα. CONCLUSION: The series exhibited a potential antitumor activity in human carcinoma cell lines encoding PI3Kα and/or ERα.

Synthesis and in Vivo Lipid-Lowering Activity of Novel Imidazoles-5-carboxamide Derivatives in Triton-WR-1339-Induced Hyperlipidemic Wistar Rats.

A new series of imidazole-5-carboxamide derivatives were prepared and tested for their anti-hyperlipidemic activity in Triton-WR-1339-induced hyperlipidemic Wistar rats. The purpose of this research was to improve benzophenone carboxamides water solubility maintaining at the same time the antihyperlipidemic activity. Compounds 4, 6, 10, and 11 were synthesized through a coupling reaction between imidazoles-5-carbonyl chloride and amino benzophenones. The tested animals (n=48) were divided into six groups: the first group (hyperlipidemic control group; HCG) received an intraperitoneal injection (i.p.) of (300 mg/kg) Triton WR-1339. The second group received i.p. injection of Triton WR-1339 followed by an intra-gastric administration of bezafibrate (100 mg/kg) (bezafibrate; BF). The third, fourth, fifth, and sixth groups received i.p. injection of Triton WR-1339 followed by an intra-gastric administration of (30 mg/kg) of compounds 4, 6, 10, and 11, respectively. At a dose of 30 mg/kg body weight compounds 4, 6, 10, and 11 significantly (p<0.0001) decreased the plasma level of triglyceride (TG), low-density lipoprotein (LDL) and total cholesterol (TC) levels after 18 h of treatment. Additionally, compounds 4, 6, 11 and bezafibrate (100 mg/kg) significantly (p<0.0001) increased the plasma level of high-density lipoprotein (HDL) levels, which is known for its preventive role against atherogenesis. These results demonstrate the possibility of pharmacokinetic properties improvement maintaining the biological and pharmacological profile of these compounds.

Benzoin Schiff Bases: Design, Synthesis, and Biological Evaluation as Potential Antitumor Agents.

BACKGROUND: Phosphoinositide 3-kinase α (PI3Kα) is an attractive target for anticancer drug design. OBJECTIVES: Target compounds were designed to probe the significance of alcohol and imine moieties tailored on a benzoin scaffold to better understand the structure activity relation (SAR) and improve their biological activity as anticancer compounds. METHODS: Chemical synthesis of the targeted compounds, biological evaluation tests against human colon adenocarcinoma (HCT-116), breast adenocarcinoma (MCF-7), and breast carcinoma (T47D) cell lines, as well as Glide docking studies were employed in this investigation. RESULTS: A new series of 1,2-diphenylimino ethanol was successfully synthesized and characterized by means of FT-IR, HRMS, NMR, and by elemental analysis. Biological screening revealed that the newly synthesized compounds inhibit PI3Kα activity in human colon adenocarcinoma (HCT-116), breast adenocarcinoma (MCF-7), and breast carcinoma (T47D) cell lines. Results additionally showed that these compounds exhibit selective antiproliferative activity, induce apoptosis, and suppress the VEGF production. Compounds 2b, 2d, and 2g displayed promising inhibitory activity in HCT-116 suggesting that hydrophobic and/or hydrogen bond-acceptor mediate(s) ligand-receptor interaction on o- and mpositions. Furthermore, compounds 2g, 2i, 2j, and 2h, bearing hydrophobic moiety on m- and pposition, exerted high antiproliferative activity in T47D and MCF-7 cells, whereas compound 2e showed selectivity against T47D and MCF-7. Molecular docking studies against PI3Kα and caspase-3 demonstrated a strong correlation between the predicted binding affinity (ΔGobsd) and IC50 values of prepared compounds for the caspase-3 model, implying that the cellulous inhibitory activity was caspase-3-dependent. Moreover, Glide docking against PI3Kα identified Ser774, Lys802, E849, V851, and Asp933 as key binding residues. CONCLUSION: The series exerted a potential PI3Kα inhibitory activity in human carcinoma cell lines expressing PI3Kα.

Structure-Based Design: Synthesis, X-ray Crystallography, and Biological Evaluation of N-Substituted-4-Hydroxy-2-Quinolone-3-Carboxamides as Potential Cytotoxic Agents.

BACKGROUND: Oncogenic potential of phosphatidylinositol 3-kinase (PI3Kα) has been highlighted as a therapeutic target for anticancer drug design. OBJECTIVE: Target compounds were designed to address the effect of different substitution patterns at the N atom of the carboxamide moiety on the bioactivity of this series. METHODS: Synthesis of the targeted compounds, crystallography, biological evaluation tests against human colon carcinoma (HCT-116), and Glide docking studies. RESULTS: A new series of N-substituted- 4-hydroxy-2-quinolone-3-carboxamides was prepared and characterized by means of FT-IR, 1H and 13C NMR, and elemental analysis. In addition, the identity of the core nucleus 5 was successfully characterized with the aid of X-ray crystallography. Biological activity of prepared compounds was investigated in vitro against human colon carcinoma (HCT-116) cell line. Results revealed that these compounds inhibit cell proliferation and induce apoptosis through an increase in caspase-3 activity and a decrease in DNA cellular content. Compounds 7, 14, and 17 which have H-bond acceptor moiety on p-position displayed promising PI3Kα inhibitory activity. On the other hand, derivatives tailored with bulky and hydrophobic motifs (16 and 18) on o- and m-positions exhibited moderate activity. Molecular docking studies against PI3Kα and caspase-3 showed an agreement between the predicted binding affinity (ΔGobsd) and IC50 values of the derivatives for the caspase-3 model. Furthermore, Glide docking studies against PI3Kα demonstrated that the newly synthesized compounds accommodate PI3Kα kinase catalytic domain and form H-bonding with key binding residues. CONCLUSION: The series exhibited a potential PI3Kα inhibitory activity in HCT-116 cell line.

Computer-aided design, synthesis, and biological evaluation of new indole-2-carboxamide derivatives as PI3Kα/EGFR inhibitors.

Structure-based drug design and molecular modeling were employed to identify a new series of indole-2-carboxamides as potential anticancer agents. These compounds were synthesized and characterized with the aid of several spectroscopic techniques, such as FT-IR, NMR, and mass spectrometry as well as by elemental analysis. Molecular docking studies confirmed that the newly synthesized compounds accommodate PI3Kα and EGFR kinase catalytic sites and form H-bonding with the key binding residues. The antitumor activity of these new compounds against an array of cancer cell lines (human colon carcinoma (HCT116), leukemia (K562), and breast cancer (MDA231) was evaluated. Results revealed that these compounds were selective against the kinase domain, and none of them showed any inhibitory activity against K562. In addition, results showed that compound 13 exhibited high potency in HCT116 and MDA231 with IC50 values of 19 and 15µM, respectively. Our findings recommend that further optimization of this series would be beneficial for colon and breast cancer treatment.

Molecular modeling based approach, synthesis, and cytotoxic activity of novel benzoin derivatives targeting phosphoinostide 3-kinase (PI3Kα).

The oncogenic potential of phosphatidylinositol 3-kinase (PI3Kα) has made it an attractive target for anticancer drug design. In this work, we describe our efforts to optimize the lead PI3Kα inhibitor 2-hydroxy-1,2-diphenylethanone (benzoin). A series of 2-oxo-1,2-diphenylethyl benzoate analogs were identified as potential PI3Kα inhibitors. Docking studies confirmed that the aromatic interaction is mediating ligand/protein complex formation and identified Lys802 and Val851 as H-bonding key residues. Our biological data in human colon carcinoma HCT116 showed that the structure analogs inhibited cell proliferation and induced apoptosis.

Crystal structure of 5-[bis-(methyl-sulfon-yl)meth-yl]-1,3-dimethyl-5-(methyl-sulfon-yl)pyrimidine-2,4,6(1H,3H,5H)-trione.

In the title compound, C10H16N2O9S3, the pyrimidine ring of the 1,3-dimethyl barbituric acid moiety has an envelope conformation with the C atom carrying the methyl-sulfonyl and bis-(methyl-sulfon-yl)methyl substituents as the flap. The dihedral angle between mean plane of the pyrimidine ring and the S/C/S plane is 72.4 (3)°. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming a three-dimensional structure.

Bis(methyl-sulfon-yl)methane.

In the title compound, C3H8O4S2, the two central S-C(H2) bond lengths are almost identical [1.781 (2) and 1.789 (2) Å]. In the crystal, each mol-ecule utilizes CH2 and CH3 bonds to form weak C-H⋯O hydrogen bonds to six other mol-ecules, thus linking mol-ecules into a three-dimensional network.

Crystal structure of 1,3-di-cyclo-hexyl-4,5-dimethyl-1H-imidazol-3-ium-2-carbodi-thio-ate chloro-form monosolvate.

The title compound, C18H28N2S2·CHCl3, crystallizes as a zwitterion. The C-S bonds are almost equivalent, with lengths of 1.666 (3) and 1.657 (3) Å. The S-C-S bond angle is expanded to 129.54 (16)° and the N-C-N angle is reduced to the tetra-hedal value of 108.8 (2)°. In the crystal, adjacent mol-ecules are linked via C-H⋯S hydrogen bonds, forming chains along [100]. The chloro-form solvent mol-ecule, which is disordered over two positions [occupancy ratio = 0.51 (2):0.49 (2)], is linked to the chain by bifurcated C-H⋯(S,S) hydrogen bonds.