Synthesis of novel 1,2-bis-quinolinyl-1,4-naphthoquinones: ERK2 inhibition, cytotoxicity and molecular docking studies

Design, synthesis, molecular dynamics simulation, MM/GBSA studies and kinesin spindle protein inhibitory evaluation of some 4-aminoquinoline hybrids

The discovery of novel chemotherapeutic agents is always challenging for researchers in industry and academia. Among the recent promising anticancer therapeutic targets, an important modulatory factor in mitosis is the expression of the kinesin family motor protein (Eg5). In terms of chemotherapy treatment, mitosis has gained significant attention due to its role as one of the biological processes that can be intervened in it. This study was undertaken to design, synthesise and evaluation of 4-aminoquinoline hybrid compounds as potential Eg5 inhibitors. Based on data collected from Malachite green and steady state ATPase assays, it has been determined that compounds such as 6c, 6d, 6g, and 6h are sensitive to Eg5 inhibition. In special mention, compounds 4 and 6c showed promising inhibitory activity in Malachite green assay with IC₅₀ values of 2.32 ± 0.23 µM and 1.97 ± 0.23 µM respectively. Compound 4 showed favourable inhibitory potential Steady state ATPase Assay with IC₅₀ value of 5.39 ± 1.39 µM. We performed molecular docking, MM/GBSA calculations, and molecular dynamic simulations to evaluate the interactions between ligands and the binding site of the kinesin spindle protein to evaluate the functional consequences of these interactions. As a result of these findings, it can be concluded that these 4-amioquinoline Schiff's base hybrids may prove to be promising candidates for development as novel inhibitors of Eg5. Further in-vivo research in this area is required.

Isobavachalcone Activates Antitumor Immunity on Orthotopic Pancreatic Cancer Model: A Screening and Validation

Pancreatic cancer is accompanied by poor prognosis and accounts for a significant number of deaths every year. Since Psoralea corylifolia L. (PCL) possesses a broad spectrum of bioactivities, it is commonly used in traditional Chinese medicine. The study explored potential antitumor agents of PCL and underlying mechanisms in vitro and vivo. Based on network pharmacology, bioinformatics, and molecular docking, we considered isobavachalcone (IBC) as a valuable compound. The activity and potential mechanisms of IBC were investigated by RT-qPCR, immunohistochemistry, immunofluorescence, and flow cytometry. It was confirmed that IBC could inhibit Panc 02 cell proliferation and induce apoptosis via increasing the production of reactive oxygen species. IBC could attenuate the weight of solid tumors, increase CD8⁺ T cells, and reduce M2 macrophages in the tumor tissue and spleen. Another promising finding was that IBC alleviated the proportion of myeloid-derived suppressor cells (MDSCs) in the tumor tissue but had no change in the spleen. The study of pharmacological effects of IBC was carried out and suggested IBC restrained M2-like polarization of RAW 264.7 cells by inhibiting the expression of ARG1 and MRC1 and suppressed the expression of ARG1 and TGF-β in bone marrow-derived MDSC. In summary, this research screened IBC as an antineoplastic agent, which could attenuate the growth of pancreatic cancer via activating the immune activity and inducing cell apoptosis. It might be a reference for the antitumor ability of IBC and the treatment of the tumor microenvironment in pancreatic cancer.

Design and Synthesis of (2-oxo-1,2-Dihydroquinolin-4-yl)-1,2,3-triazole Derivatives via Click Reaction: Potential Apoptotic Antiproliferative Agents

A mild and versatile method based on Cu-catalyzed [2+3] cycloaddition (Huisgen-Meldal-Sharpless reaction) was developed to tether 3,3’-((4-(prop-2-yn-1-yloxy)phenyl)methylene)bis(4-hydroxyquinolin-2(1H)-ones) with 4-azido-2-quinolones in good yields. This methodology allowed attaching three quinolone molecules via a triazole linker with the proposed mechanism. The products are interesting precursors for their anti-proliferative activity. Compound 8g was the most active one, achieving IC₅₀ = 1.2 ± 0.2 µM and 1.4 ± 0.2 µM against MCF-7 and Panc-1 cell lines, respectively. Moreover, cell cycle analysis of cells MCF-7 treated with 8g showed cell cycle arrest at the G2/M phase (supported by Caspase-3,8,9, Cytochrome C, BAX, and Bcl-2 studies). Additionally, significant pro-apoptotic activity is indicated by annexin V-FITC staining.

Structure based designing of thiazolidinone-pyrimidine derivatives as ERK2 inhibitors: Synthesis and in vitro evaluation

Breast cancer has been associated with an overexpression of various molecular targets; accordingly, various target-specific chemotherapeutic agents have been developed. Inhibition of ERK2, a member of MAPK pathway, is an important target involved in the treatment of both oestrogen receptor-positive and triple-negative breast cancer. Thus, in continuation of our previous work on the ERK2 target, we here report novel inhibitors of this kinase. Out of three lead molecules reported in our previous study, we selected the thiazolidinone-pyrimidine scaffold for further development of small molecule inhibitors of ERK2. Analogues of the lead molecule were docked in the target kinase, followed by molecular dynamic simulations and MM-GBSA calculations. Analogues maintaining key interactions with amino acid residues in the ATP-binding domain of ERK2 were selected and duly synthesized. In vitro biochemical evaluation of these molecules against ERK2 kinase disclosed that two molecules possess significant kinase inhibitory potential with IC₅₀ values ≤ 0.5 µM.

Recent developments in mitogen activated protein kinase inhibitors as potential anticancer agents

The mitogen activated protein kinase (MAPK) belongs to group of kinase that links the extracellular stimuli to intracellular response. The MAPK signalling pathway (RAS-RAF-MEK-ERK) involved in different pathological conditions like cancer, caused due to genetic or any other factor such as physical or environmental. Many studies have been conducted on the pathological view of MAPK cascade and its associated element like RAS, RAF, MEK, ERK or its isoforms, and still the research is going on particularly with respect to its activation, regulation and inhibition. The MAPK signalling pathway has become the area of research to identify new target for the management of cancer. A number of heterocyclics are key to fight with the cancer associated with these enzymes thus give some hope in the management of cancer by inhibiting MAPK cascade. In the present article, we have focussed on MAPK signalling pathway and role of different heterocyclic scaffolds bearing nitrogen, sulphur and oxygen and about their potential to block MAPK signalling pathway. The heterocyclics are gaining importance due to high potency and selectivity with less off-target effects against different targets involved in the MAPK signalling pathway. We have tried to cover recent advancements in the MAPK signalling pathway inhibitors with an aim to get better understanding of the mechanism of action of the compounds. Several compounds in the preclinical and clinical studies have been thoroughly dealt with. In addition to the synthetic compounds, a significant number of natural products containing heterocyclic moieties as MAPK signalling pathway inhibitors have been put together. The structure activity relationship along with docking studies have been discussed to apprehend the mechanistic studies of various compounds that will ultimately help to design and develop more MAPK signalling pathway inhibitors.

TG, DTA Pyrolytic Analysis of Cobalt, Nickel, Copper, Zinc, and 5,8-Dihydroxy-1,4-Naphthoquinone Chelate Complexes

The solid state reactions identified on the TG traces with correspondence to DTG peaks consequent to the nonisothermal decomposition of polymetallic chelates of the naphthazarin with Zn (II), Co (II), Ni (II), and Cu (II) over the temperature range ambient at 800°C have been studied kinetically following the Dave and Chopra method as these solid state reactions exhibited their resemblance with the Freeman recommended reaction for kinetic studies. The solid state reactions as described followed first order kinetics. The kinetic data showed the very low value of Z for each of the solid state reaction in reference, concluding on the solid state reactions (the nonisothermal decomposition of polymetallic chelate of Zn (II), Co (II), Ni (II), and Cu (II) as slow reactions).

Quinolines, a perpetual, multipurpose scaffold in medicinal chemistry

Quinoline is a versatile pharmacophore, a privileged scaffold and an outstanding fused heterocyclic compound with a wide range of pharmacological prospective such as anticancer, anti-inflammatory, antibacterial, antiviral drug and superlative moiety in drug discovery. The quinoline hybrids have already been shown excellent results with new targets with a different mode of actions as an inhibitor of cell proliferation by cell cycle arrest, apoptosis, angiogenesis, disruption of cell migration and modulation. This review emphasized the mode of action, structure activity relationship and molecular docking to reveal the various active pharmacophores of quinoline hybrids accountable for novel anticancer, anti-inflammatory, antibacterial and miscellaneous activities. Therefore, several quinoline candidates are under clinical trials for the treatment of certain diseases, for example ferroquine (antimalarial), dactolisib (antitumor) and pelitinib (EGFR TK inhibitors) etc. Plenty of research has been summarized the recent advances of quinoline derivatives and explore the various therapeutic prospects of this moiety. This review would help the researchers to strategically design diverse novel quinoline derivatives for the development of clinically viable drug candidates for the treatment of incurable diseases.

Design and synthesis of hydrazinecarbothioamide sulfones as potential antihyperglycemic agents

New hydrazinecarbothioamides with a phenylsulfonyl group were synthesized and their structures were identified by different spectroscopic data (¹ H NMR, ¹³ C NMR, two-dimensional NMR, mass spectrometry, elemental analysis, and single-crystal X-ray analysis). The mechanism describing the formation of the products was also discussed. The antidiabetic activity of the isolated products was investigated histochemically. The synthesized sulfonylalkylthiosemicarbazide exhibited antihyperglycemic activity in streptozotocin-induced diabetic mice. Compounds 5a and 5c significantly lowered the blood glucose level to 103.3 ± 1.8 and 102 ± 3.9 mg/dl, respectively. Also, they caused a significant decrease in malondialdehyde levels and normalized the glutathione levels in streptozotocin-induced diabetic mice, compared with the diabetic group. The results suggest that the synthesized hydrazinocarbothioamides may effectively inhibit the development of oxidative stress in diabetes.

Synthesis, Cytotoxic Activity Evaluation and Quantitative Structure-Activity Analysis of Substituted 5,8-Dihydroxy-1,4-Naphthoquinones and their O- and S-Glycoside Derivatives Tested Against Neuro-2a Cancer Cells

Based on 6,7-substituted 2,5,8-trihydroxy-1,4-naphtoquinones (1,4-NQs) derived from sea urchins, five new acetyl-O-glucosides of NQs were prepared. A new method of conjugation of per-O-acetylated 1-mercaptosaccharides with 2-hydroxy-1,4-NQs through a methylene spacer was developed. Methylation of 2-hydroxy group of quinone core of acetylthiomethylglycosides by diazomethane and deacetylation of sugar moiety led to 28 new thiomethylglycosidesof 2-hydroxy- and 2-methoxy-1,4-NQs. The cytotoxic activity of starting 1,4-NQs (13 compounds) and their O- and S-glycoside derivatives (37 compounds) was determined by the MTT method against Neuro-2a mouse neuroblastoma cells. Cytotoxic compounds with EC50 = 2.7-87.0 μM and nontoxic compounds with EC50 > 100 μM were found. Acetylated O- and S-glycosides 1,4-NQs were the most potent, with EC50 = 2.7-16.4 μM. Methylation of the 2-OH group innaphthoquinone core led to a sharp increase in the cytotoxic activity of acetylated thioglycosidesof NQs, which was partially retained for their deacetylated derivatives. Thiomethylglycosides of 2-hydroxy-1,4-NQs with OH and MeO groups in quinone core at positions 6 and 7, resprectively formed a nontoxic set of compounds with EC50 > 100 μM. A quantitative structure-activity relationship (QSAR) model of cytotoxic activity of 22 1,4-NQ derivatives was constructed and tested. Descriptors related to the cytotoxic activity of new 1,4-NQ derivatives were determined. The QSAR model is good at predicting the activity of 1,4-NQ derivatives which are unused for QSAR models and nontoxic derivatives.

Synthesis of potentially new schiff bases of N-substituted-2-quinolonylacetohydrazides as anti-COVID-19 agents

We report herein a new series of synthesized N-substituted-2-quinolonylacetohydrazides aiming to evaluate their activity towards SARS-CoV-2. The structures of the obtained products were fully confirmed by NMR, mass, IR spectra and elemental analysis as well. Molecular docking calculations showed that most of the tested compounds possessed good binding affinity to the SARS-CoV-2 main protease (M^pro) comparable toRemdesivir.

Synthesis of 3,3'-methylenebis(4-hydroxyquinolin-2(1H)-ones) of prospective anti-COVID-19 drugs

During formylation of 2-quinolones by DMF/Et₃N mixture, the unexpected 3,3'-methylenebis(4-hydroxyquinolin-2(1H)-ones) were formed. The discussed mechanism was proved as due to the formation of 4-formyl-2-quinolone as intermediate. Reaction of the latter compound with the parent quinolone under the same reaction condition gave also the same product. The structure of the obtained products was elucidated via NMR, IR and mass spectra. X-ray structure analysis proved the anti-form of the obtained compounds, which were stabilized by the formation hydrogen bond. Molecular docking calculations showed that most of the synthesized compounds possessed good binding affinity to the SARS-CoV-2 main protease (M^pro) in comparable to Darunavir.

Regioselective synthesis of new 7,8-dichlorobenzofuro[3,2-c]quinoline-6,9,10(5H)-triones from reactions of 4-hydroxy-2-quinolones with 3,4,5,6-tetrachloro-1,2-benzoquinone

A novel series of 7,8-dichlorobenzofuro[3,2- c]quinoline-6,9,10(5 H)-triones was obtained regioselectively in good yields. The products were formed by the reactions of the 4-hydroxy-2(1 H)-quinolinones with 3,4,5,6-tetrachloro-1,2-benzoquinone in tetrahydrofuran as the solvent. Infrared, nuclear magnetic resonance (two-dimensional nuclear magnetic resonance), mass spectra and elemental analysis were used to elucidate the structures of new compounds.

An update on chemical classes targeting ERK1/2 for the management of cancer

Cancer, still in the limelight due to its dreadful nature, shows overexpression of multiple signaling macromolecules leading to failure of many chemotherapeutic agents and acquired resistance to chemotherapy. These factors highlight the significance of shifting toward targeted therapy in cancer research. Recently, ERKs (ERK1 and 2) have been established as a promising target for the management of various types of solid tumors, due to their aberrant involvement in cell growth and progression. Several ERKs inhibitors have reached clinical trials for the management of cancer and their derivatives are being continuously reported with noteworthy anticancer effect. This review highlights the recent reports on various chemical classes involved in the development of ERKs inhibitors along with their in vitro and in vivo activity and structure-activity relationship profile.

Synthesis of New Fused Heterocyclic 2-Quinolones and 3-Alkanonyl-4-Hydroxy-2-Quinolones

Herein, we report the synthesis of 5,12-dihydropyrazino[2,3-c:5,6-c′]difuro[2,3-c:4,5-c′]-diquinoline-6,14(5H,12H)diones, 2-(4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)-1,4-diphenyl- butane-1,4-diones and 4-(benzo-[d]oxazol-2-yl)-3-hydroxy-1H-[4,5]oxazolo[3,2-a]pyridine-1-one. The new candidates were synthesized and identified by different spectroscopic techniques, and X-ray crystallography.

Design, synthesis, and DNA interaction studies of furo-imidazo[3.3.3]propellane derivatives: Potential anticancer agents

A large number of natural products containing the propellane scaffold have been reported to exhibit cytotoxicity against several cancers; however, their mechanism of action is still unknown. Anticancer drugs targeting DNA are mainly composed of small planar molecule/s that can interact with the DNA helix, causing DNA malfunction and cell death. The aim of this study was to design and synthesize propellane derivatives that can act as DNA intercalators and/or groove binders. The unique structure of the propellane derivatives and their ability to display planar ligands with numerous possible geometries, renders them potential starting points to design new drugs targeting DNA in cancer cells. New substituted furo-imidazo[3.3.3]propellanes were synthesized via the reaction of substituted alkenylidene-hydrazinecarbothioamides with 2-(1,3-dioxo-2,3-dihydro-1H-2-ylidene)propanedinitrile in tetrahydrofuran at room temperature. The structures of the products were confirmed by a combination of elemental analysis, NMR, ESI-MS, IR and single crystal X-ray analysis. Interestingly, 5c, 5d and 5f showed an ability to interact with Calf Thymus DNA (CT-DNA). Their DNA-binding mode was investigated using a combination of absorption spectroscopy, DNA melting, viscosity, CD spectroscopy measurements, as well as competitive binding studies with several dyes. Their cytotoxicity was evaluated against the NCI-60 panel of cancer cell lines. 5c, 5d and 5f exhibited similar anti-proliferative activity against the A549 non-small cell lung cancer (NSCLC) cell line. Further mechanistic studies revealed their ability to induce DNA damage in the A549 cell line, as well as apoptosis, evidenced by elevated Annexin V expression, enhanced caspase 3/7 activation and PARP cleavage. In this study, we present the potential for designing novel propellanes to provoke cytotoxic activity, likely through DNA binding-induced DNA damage and apoptosis.

Design, synthesis and biological evaluation of fused naphthofuro[3,2-c] quinoline-6,7,12-triones and pyrano[3,2-c]quinoline-6,7,8,13-tetraones derivatives as ERK inhibitors with efficacy in BRAF-mutant melanoma

Approximately 60% of human cancers exhibit enhanced activity of ERK1 and ERK2, reflecting their multiple roles in tumor initiation and progression. Acquired drug resistance, especially mechanisms associated with the reactivation of the MAPK (RAF/MEK/ERK) pathway represent a major challenge to current treatments of melanoma and several other cancers. Recently, targeting ERK has evolved as a potentially attractive strategy to overcome this resistance. Herein, we report the design and synthesis of novel series of fused naphthofuro[3,2-c]quinoline-6,7,12-triones 3a-f and pyrano[3,2-c]quinoline-6,7,8,13-tetraones 5a,b and 6, as potential ERK inhibitors. New inhibitors were synthesized and identified by different spectroscopic techniques and X-ray crystallography. They were evaluated for their ability to inhibit ERK1/2 in an in vitro radioactive kinase assay. 3b and 6 inhibited ERK1 with IC50s of 0.5 and 0.19 µM, and inhibited ERK2 with IC50s of 0.6 and 0.16 µM respectively. Kinetic mechanism studies revealed that the inhibitors are ATP-competitive inhibitors where 6 inhibited ERK2 with a K_i of 0.09 µM. Six of the new inhibitors were tested for their in vitro anticancer activity against the NCI-60 panel of tumor cell lines. Compound 3b and 6 were the most potent against most of the human tumor cell lines tested. Moreover, 3b and 6 inhibited the proliferation of the BRAF mutant A375 melanoma cells with IC50s of 3.7 and 0.13 µM, respectively. In addition, they suppressed anchorage-dependent colony formation. Treatment of the A375 cell line with 3b and 6 inhibited the phosphorylation of ERK substrates p-90RSK and ELK-1 and induced apoptosis in a dose dependent manner. Finally, a molecular docking study showed the potential binding mode of 3b and 6 within the ATP catalytic binding site of ERK2.