Synthesis and cytotoxic activity of certain benzothiazole derivatives against human MCF‐7 cancer cell line

A new series of benzothiazole has been synthesized as cytotoxic agents. The new derivatives were tested for their cytotoxic activity toward the human breast cancer MCF‐7 cell line against cisplatin as the reference drug. Many derivatives revealed good cytotoxic effect, whereas four of them, 4, 5c, 5d, and 6b , were more potent than cisplatin, with IC₅₀ values being 8.64, 7.39, 7.56, and 5.15 μm compared to 13.33 μm of cisplatin. The four derivatives’ cytotoxic activity was accompanied by regulating free radicals production, by increasing the activity of superoxide dismutase and depletion of intracellular reduced glutathione, catalase, and glutathione peroxidase activities, accordingly, the high production of hydrogen peroxide, nitric oxide, and other free radicals causing tumor cell death as monitored by reduction in the synthesis of protein and nucleic acids. Most of the tested compounds showed potent to moderate growth inhibitory activity; in particular, compound 6b exhibited the highest activity suggesting it is a lead compound in cytotoxic activity.     

Oestrogenic activity of mimosine on MCF‐7 breast cancer cell line through the ERα‐mediated pathway

Hormone replacement therapy has been a conventional treatment for postmenopausal symptoms in women. However, it has potential risks of breast and endometrial cancers. The aim of this study was to evaluate the oestrogenicity of a plant‐based compound, mimosine, in MCF‐7 cells by in silico model. Cell viability and proliferation, ERα‐SRC1 coactivator activity and expression of specific ERα‐dependent marker TFF1 and PGR genes were evaluated. Binding modes of 17β‐oestradiol and mimosine at the ERα ligand binding domain were compared using docking and molecular dynamics simulation experiments followed by binding interaction free energy calculation with molecular mechanics/Poisson–Boltzmann surface area. Mimosine showed increased cellular viability (64,450 cells/ml) at 0.1 μM with significant cell proliferation (120.5%) compared to 17β‐oestradiol (135.2%). ER antagonist tamoxifen significantly reduced proliferative activity mediated by mimosine (49.9%). Mimosine at 1 μM showed the highest ERα binding activity through increased SRC1 recruitment at 186.9%. It expressed TFF1 (11.1‐fold at 0.1 μM) and PGR (13.9‐fold at 0.01 μM) genes. ERα‐mimosine binding energy was ?49.9 kJ/mol, and it interacted with Thr347, Gly521 and His524 of ERα‐LBD. The results suggested that mimosine has oestrogenic activity.     

1,2,4‐Triazole hybrids with potential antibacterial activity against methicillin‐resistant Staphylococcus aureus

Methicillin‐resistant Staphylococcus aureus (MRSA) has developed numerous mechanisms of virulence and strategies to evade the human immune system, and it can be transmitted between humans, animals, and the environment. Thus, MRSA is an important cause of morbidity and mortality in both hospitals and in the community, creating an urgent demand for the development of novel anti‐MRSA candidates. The 1,2,4‐triazole nucleus is a bioisostere of amide, ester, and carboxylic acid, and the 1,2,4‐triazole ring is found in many compounds with diverse biological effects. 1,2,4‐Triazole derivatives could exert their antibacterial activity through inhibition of efflux pumps, filamentous temperature‐sensitive protein Z, penicillin‐binding protein, DNA gyrase, and topoisomerase IV, and they play an important role in the discovery of novel antibacterial agents. Among them, 1,2,4‐triazole hybrids, which have the potential to exert dual/multiple mechanisms of action, possess a promising broad‐spectrum antibacterial activity against a panel of clinically important drug‐resistant pathogens including MRSA. This review outlines the recent developments of 1,2,4‐triazole hybrids with a potential anti‐MRSA activity, covering articles published between 2010 and 2020. The mechanisms of action, critical aspects of their design, and structure–activity relationships are also discussed.     

Discovery and structure–activity relationship of plastoquinone analogs as anticancer agents against chronic myelogenous leukemia cells

Two series of amino‐1,4‐benzoquinones ( AQ1–18 ) based on the structural analogs of plastoquinones were synthesized and the structure–activity relationship against chronic myelogenous leukemia activity was examined. All of the synthesized compounds were tested for their cytotoxic effects on different leukemic cell lines. Of interest, AQ15 exhibited a better selectivity than the reference drug imatinib on cancer cells. Owing to this, AQ15 was selected for a further apoptosis/necrosis evaluation where AQ15 ‐treated K562 cells demonstrated similar apoptotic effects like imatinib‐treated cells at their IC₅₀ values. The inhibitory effects of AQ15 and the other three compounds with various activities against eight tyrosine kinases, including ABL1, were investigated. AQ15 showed weak activity against ABL1, and a correlation was observed between the anti‐K562 and anti‐ABL1 activities. The binding mode of AQ15 into the ATP binding pocket of ABL1 kinase was predicted in silico, showing the formation of some key interactions. In addition, AQ15 was shown to suppress the downstream signaling of BCR‐ABL in K562 cells. Finally, AQ15 obviously cleaved DNA in the presence of an iron(II) complex system, indicating that this can be the major mechanism of its antiproliferative action, whereas the mild inhibition of ABL kinase is just in‐part mechanism of its overall outstanding cellular activity.     

3‐(3‐Ethylphenyl)‐2‐substituted hydrazino‐3H‐quinazolin‐4‐one Derivatives: New Class of Analgesic and Anti‐Inflammatory Agents

A new series of 3‐(3‐ethylphenyl)‐2‐substituted hydrazino‐3H‐quinazolin‐4‐ones were synthesized by reacting the amino group of 2‐hydrazino‐3‐(3‐ethylphenyl)‐3H‐quinazolin‐4‐one with a variety of aldehydes and ketones. The title compounds were investigated for analgesic, anti‐inflammatory and ulcerogenic index behavior. The compound 2‐(N′‐3‐pentylidene‐hydrazino)‐3‐(3‐ethylphenyl)‐3H‐quinazolin‐4‐one ( AS2 ) emerged as the most active compound in exhibiting analgesic activity and the compound 2‐(N′‐2‐pentylidene‐hydrazino)‐3‐(3‐ethylphenyl)‐3H‐quinazolin‐4‐one ( AS3 ) emerged as the most active compound in exhibiting anti‐inflammatory activity; and these compounds are moderately potent when compared with the reference standard diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic potential when compared with aspirin.     

Synthesis of new arylazopyrazoles as apoptosis inducers: Candidates to inhibit proliferation of MCF‐7 cells

New 4‐arylazo‐3,5‐diamino‐1H‐pyrazole derivatives substituted in the 4‐aryl ring with the acetyl moiety were designed and synthesized. The antiproliferative activity of the novel arylazopyrazoles was examined against the MCF‐7 cell line. Among all target compounds, 8b (IC₅₀ 3.0 µM) and 8f (IC₅₀ 4.0 µM) displayed higher cytotoxicity as compared with the reference standard imatinib (IC₅₀ 7.0 µM). Further studies to explore the mechanism of action were performed on the most active hit of our library, 8b , via anti‐CDK2 kinase activity. It demonstrated good inhibitory effects for CDK2 (IC₅₀ 0.24 µM) with 62.5% inhibition, compared with imatinib. The cell cycle analysis in the MCF‐7 cell line revealed apoptosis induction by 8b and cell cycle arrest at the S phase. Docking in the CDK2 active site and pharmacophore modeling confirmed the affinity of 8b to the CDK2 active site. Absorption, distribution, metabolism, and excretion studies revealed that our target compounds are orally bioavailable, with no permeation through the blood–brain barrier.     

1H‐1,2,3‐triazole‐tethered uracil‐ferrocene and uracil‐ferrocenylchalcone conjugates: Synthesis and antitubercular evaluation

Copper‐catalyzed azide‐alkyne [3 + 2] cycloaddition has been utilized for preparing a series of 1H‐1,2,3‐triazoles with the purpose of probing structure–activity relationships among a uracil‐ferrocene‐triazole conjugate family. The antitubercular evaluation studies revealed an improvement in activity with the introduction of a ferrocene nucleus among N‐alkylazido‐uracil precursors, with a preference for a bromo‐substituent along with moderate chain lengths of n = 2–6. The reported protocol is a successful approach for integrating uracil‐ferrocene‐chalcone functionalities tethered via 1H‐1,2,3‐triazole rings with apparent physicochemical stability.     

The estrogenic proliferative effects of two alkylphenols and a preliminary mechanism exploration in MCF‐7 breast cancer cells

Bisphenol A (BPA) and 4‐cumylphenol (4‐CP), as estrogen‐like chemicals, are ubiquitous in the environment media and associated with the occurrence and development of hormone‐dependent tumors. However, the combinatorial effects of these two structurally similar alkylphenols are not well informed. In the present study, the classic breast cancer cell line MCF‐7 was used as in vitro model to estimate the estrogenic proliferative effects of BPA and 4‐CP. MTT assay, reactive oxygen species, cell apoptosis, cell cycle, and real‐time fluorescent quantitative Step One Plus Real‐time PCR System (Applied Biosystems, CA, USA) were applied to explore their proliferative mechanisms. MTT results showed that both BPA and 4‐CP ranging from 10^?9 to 10^?5 M stimulated cell proliferation in a nonmonotonic dose‐response manner. Along with the proliferative effects, cell cycle was progressed from G0/G1 to S and G2/M phase. Meanwhile, the expression levels of ERα, pS2, and Bcl‐2 mRNA were also upregulated. In contrast, 4‐CP and BPA at high dose (10^?4 M) obviously displayed antiproliferative effects in MCF‐7 cells via inducing cell apoptosis and blocking cell cycle in G0/G1 phase. As expected, the relative expression levels of ERα, pS2, and Bcl‐2 mRNA were decreased, whereas Bax mRNA was increased. Interestingly, the proliferative or antiproliferative effects of 4‐CP were higher than that of BPA. Moreover, coexposure of lower concentrations BPA and 4‐CP significantly induced cell proliferation in a synergistic manner. These findings indicated that the potential environmental risks of coexposure of BPA and 4‐CP were greater than either of them.     

Novel 3‐substituted N‐methylcarbazole–imidazolium salt derivatives: Synthesis and cytotoxic activity

A series of novel 3‐substituted N‐methylcarbazole–imidazolium salt derivatives has been prepared and evaluated in vitro against a panel of tumor cell lines (Hep G‐2, Hela and PC12). The results suggest that the presence of substituted 2‐methyl‐imidazole or imidazole ring and substitution of the imidazolyl‐3‐position with a naphthylacyl or 4‐bromophenacyl group were important for improving cytotoxic activity. Compounds 17 , 18 , 27, and 28 with 4‐bromophenacyl and naphthylacyl groups displayed good activities with IC₅₀ values of 0.09–7.20 μm against three tumor cell lines investigated and more active than DDP. Compound 35 exhibited cytotoxic activity selectively against Hela cell.     

Indolizine Derivatives as HIV‐1 VIF–ElonginC Interaction Inhibitors

Compound 1 (VEC‐5) was identified as a potent small‐molecular HIV‐1 viron infectivity factor inhibitor that targets the viron infectivity factor–ElonginC interaction. A structure–activity relationship study was carried out to develop compounds with improved efficacy against HIV‐1 and 49 indolizine derivatives of three categories were designed and synthesized. We found that five compounds exhibited promising anti‐HIV‐1 activity, and the most active compound 2g had an IC₅₀ value of 11.0 μm . These results provide new information to develop highly potent small‐molecule HIV‐1 viron infectivity factor inhibitors.     

Differences in the mechanisms of action of BDE‐47 and its metabolites on OVCAR‐3 and MCF‐7 cell apoptosis

Data concerning possible carcinogenic action of polybrominated diphenyl ethers (PBDEs) in hormone‐dependent tissues are limited. Our earlier studies showed that 2,2′,4,4′‐tetrabromodiphenyl ether (BDE‐47) stimulated OVCAR‐3 and MCF‐7 cell proliferation, while its hydroxylated metabolites (5‐OH‐BDE‐47 and 6‐OH‐BDE‐47) increased estrogen receptors protein expression and extracellular signal‐regulated kinase 1/2 and protein kinase Cα phosphorylation in these cell lines. In addition to cell proliferative disorder, a failure in the regulation of apoptosis can also lead to the formation and development of tumors. Therefore, in the present study, we investigated the effect of BDE‐47 and its metabolites (2.5–50 ng ml^–1) on the expression of apoptosis regulatory genes and proteins, caspase‐8 and ‐9 activity and DNA fragmentation induced by extracellular signal‐regulated kinase inhibitor (PD098059) and protein kinase Cα inhibitor (Gӧ 6976) in ovarian (OVCAR‐3) and breast (MCF‐7) cancer cells. In OVCAR‐3 cells, BDE‐47 upregulated expression of most of the investigated genes and increased protein expression of tumor necrosis factor (TNF)‐α, TNF receptor 1, caspase‐6, Bcl‐xl and caspase‐8 activity. Whereas in MCF‐7 cells, BDE‐47 resulted in the downregulation of most of the investigated genes, and decreased caspase‐8 and ‐9 activity. In both OVCAR‐3 and MCF‐7 cells, the expression of most of the investigated genes were downregulated by metabolites. Exposure of OVCAR‐3 cells to 5‐OH‐BDE‐47 corresponded with a decrease in the protein expression of caspase‐6, caspase‐9 and Bcl‐xl and treatment with 6‐OH‐BDE‐47 decreased Bcl‐xl and TNF receptor 1 expression in OVCAR‐3 cells and caspase‐9 expression in MCF‐7 cells. Hydroxylated metabolites of BDE‐47 have strong inhibitory effects on apoptosis in ovarian and breast tumor cells and thus should be considered potential carcinogens in hormone‐dependent cancers. Copyright © 2016 John Wiley & Sons, Ltd.     

In vitro profiling of toxicity and endocrine disrupting effects of bisphenol analogues by employing MCF‐7 cells and two‐hybrid yeast bioassay

The potentially adverse health implications of bisphenol A (BPA) have led to increasing use of alternative bisphenols (BPs). However, little is known about the toxicity of alternative BPs. In this study, the cytotoxicity, genotoxicity, intracellular ROS formation, and Ca²⁺ fluctuation effects of BPs on MCF‐7 cells were evaluated. At the same time, the estrogenic and thyroidal hormone effect potentials of six BPs were also evaluated using two‐hybrid yeast bioassay. The results showed that most BPs at 0.01–1 μM significantly increased cell viability in MCF‐7 cells and at higher exposure concentrations of 25–100 μM, they caused a significant decrease of cell viability. At the same time, these BPs also at 25–100 μM significantly increased LDH release of MCF‐7 cells. In addition, several BPs at 10–50 μM resulted in a significantly concentration‐depended increase in DNA‐damaging effect on MCF‐7 cells and elevated ROS production. Most BPs at 0.0001–10 μM significantly increased intracellular Ca²⁺ level. These results showed that bisphenol AF (BPAF) and thiodiphenol (TDP) exerted cell biological effect, estrogenic, and thyroidal effect potentials greater than those of BPA. The cytotoxicity and endocrine disrupting effects of other BPs are similar to or slightly lower than those of BPA. Therefore, as potential alternatives to BPA, endocrine disrupting effects and potential health harm of alternative BPs to human can also not be ignored. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 278–289, 2017.     

Design and synthesis of 2‐phenyl benzimidazole derivatives as VEGFR‐2 inhibitors with anti‐breast cancer activity

Three new series of 2‐phenyl benzimidazole‐based derivatives were designed, synthesized, and evaluated for their in vitro cytotoxic activity against breast cancer (MCF‐7) cell lines. Three compounds 8 , 9 , and 15 showed high cytotoxic activities, with IC₅₀ values of 3.37, 6.30, and 5.84 μM, respectively, while they showed comparable cytotoxicity to the standard drug doxorubicin against human normal cells, including nontumorigenic breast epithelial cell line (MCF‐10F), skin fibroblast cell line (BJ), and lung fibroblast cell line (MRC‐5). Six of the synthesized compounds were screened against vascular endothelial growth factor receptor 2 (VEGFR‐2) where compounds 8 , 9 , 12 , and 15 exhibited an outstanding potency in comparison with sorafenib, with IC₅₀ values of 6.7–8.9 nM. Molecular docking study assessed the good binding patterns of the most potent compounds with the reported conserved amino acids of VEGFR‐2 active site.     

Synthesis and Antimycobacterial Activity of Novel Thiadiazolylhydrazones of 1‐Substituted Indole‐3‐carboxaldehydes

A series of novel thiocarbohydrazones of substituted indoles and their corresponding thiadiazole derivatives were prepared, and their structures were confirmed by different analytical and spectroscopic methods. The derivatives were prepared by a sequential synthetic strategy including substitution at N‐1 position of indole ring by various aliphatic and benzylic substituents, followed by condensation with thiocarbohydrazide, and finally cyclization by triethyl orthoformate. The derivatives were tested for their antimycobacterial activity against Mycobacterium bovis BCG, and the results revealed that among the synthesized compounds, thiadiazole derivatives 4e , 4f , 4n , 4p , 4q , and 4t exhibited the highest activity with IC₅₀ value of 3.91 μg/mL. The results indicate that the thiadiazole moiety plays a vital role in exerting antimycobacterial activity.