Design, synthesis, docking, and anticancer evaluations of new thiazolo[3,2-a] pyrimidines as topoisomerase II inhibitors

New thiazolopyrimidine derivatives 2, 3a-d, 4a-c, 5, 6a-c, and 7a,b were synthesised. All prepared compounds were evaluated by MTT cytotoxicity assay against three human tumour cell lines. Compounds 3c, 3d, 4c, 6a, 6b, and 7b exhibited potent to strong anticancer activity that was nearly comparable or superior to Doxorubicin. Compounds exhibiting significant cytotoxicity were further selected to study their inhibitory activity on the Topo II enzyme. Compound 4c was the most potent Topo II inhibitor with an IC₅₀ value of 0.23 ± 0.01 µM, which was 1.4-fold and 3.6-fold higher than the IC₅₀ values of Etoposide and Doxorubicin. Furthermore, compound 4c showed significant cell cycle disruption and apoptosis on A549 cells compared to control cells. Molecular docking of the most active compounds illustrated proper fitting to the Topo II active site, suggesting that our designed compounds are promising candidates for the development of effective anticancer agents acting through Topo II inhibition.

The Role of Pyrazolo[3,4-d]pyrimidine-Based Kinase Inhibitors in The Attenuation of CCl4-Induced Liver Fibrosis in Rats

Liver Fibrosis can be life-threatening if left untreated as it may lead to serious, incurable complications. The common therapeutic approach is to reverse the fibrosis while the intervention is still applicable. Celecoxib was shown to exhibit some antifibrotic properties in the induced fibrotic liver in rats. The present study aimed to investigate the possible antifibrotic properties in CCl4-induced liver fibrosis in male Sprague–Dawley rats compared to celecoxib of three novel methoxylated pyrazolo[3,4-d]pyrimidines. The three newly synthesized compounds were proved to be safe candidates. They showed a therapeutic effect against severe CCl4-induced fibrosis but at different degrees. The three compounds were able to partially reverse hepatic architectural distortion and reduce the fibrotic severity by showing antioxidant properties reducing MDA with increasing GSH and SOD levels, remodeling the extracellular matrix proteins and liver enzymes balance, and reducing the level of proinflammatory (TNF-α and IL-6) and profibrogenic (TGF-β) cytokines. The results revealed that the dimethoxy-analog exhibited the greatest activity in all the previously mentioned parameters compared to celecoxib and the other two analogs which could be attributed to the different methoxylation patterns of the derivatives. Collectively, the dimethoxy-derivative could be considered a safe promising antifibrotic candidate.

New Antagonists of the Membrane Androgen Receptor OXER1 from the ZINC Natural Product Database

OXER1 (oxoeicosanoid receptor 1) was deorphanized in 1993 and found to be the specific receptor for the arachidonic acid metabolite 5-oxo-ETE. Recently, we have reported that androgen binds to this receptor also, being a membrane androgen receptor, triggering a number of its membrane-mediated actions (cell migration, apoptosis, cell proliferation, Ca²⁺ movements). In addition, our previous work suggested that a number of natural monomeric and oligomeric polyphenols interact with OXER1, acting similar to testosterone. Here, we interrogated the natural product chemical space and identified nine polyphenolic molecules with interesting in silico pharmacological activities as putative OXER1 antagonists. The molecule with the best pharmacokinetic-pharmacodynamic properties (ZINC15959779) was purchased and tested on OXER1, in prostate cancer cell cultures. It showed that it has actions similar to those of testosterone in inhibiting cAMP, while it had no action in intracellular Ca²⁺ mobilization or actin cytoskeleton rearrangement/migration. These results are discussed under the prism of structure-activity relationships and in silico models of the OXER1 binding groove. We suggest that these compounds, together with the previously reported (poly)phenolic compounds, can be lead structures for the exploration of the anti-inflammatory and antiproliferative effects of OXER1 antagonists.

Recent Design and Structure-Activity Relationship Studies on the Modifications of DHFR Inhibitors as Anticancer Agents

BACKGROUND

Dihydrofolate reductase (DHFR) has been known for decades as a molecular target for antibacterial, antifungal and anti-malarial treatments. This enzyme is becoming increasingly important in the design of new anticancer drugs, which is confirmed by numerous studies including modelling, synthesis and in vitro biological research. This review aims to present and discuss some remarkable recent advances in the research of new DHFR inhibitors with potential anticancer activity.

METHODS

The scientific literature of the last decade on the different types of DHFR inhibitors has been searched. The studies on design, synthesis and investigation structure-activity relationships were summarized and divided into several subsections depending on the leading molecule and its structural modification. Various methods of synthesis, potential anticancer activity and possible practical applications as DHFR inhibitors of new chemical compounds were described and discussed.

RESULTS

This review presents the current state of knowledge on the modification of known DHFR inhibitors and the structures and searches for about eighty new molecules, designed as potential anticancer drugs. In addition, DHFR inhibitors acting on thymidylate synthase (TS), carbon anhydrase (CA) and even DNA-binding are presented in this paper.

CONCLUSION

Thorough physicochemical characterization and biological investigations highlight the structure-activity relationship of DHFR inhibitors. This will enable even better design and synthesis of active compounds, which would have the expected mechanism of action and the desired activity.

A facile and concise route to (hydroxybenzoyl)pyrido[2,3-d]pyrimidine heterocycle derivatives: synthesis, and structural, spectral and computational exploration

In this work, we report the efficient synthesis of novel (hydroxybenzoyl)pyrido[2,3-d]pyrimidine heterocycle derivatives: 6-(2-hydroxy-5-methylbenzoyl)-1-methylpyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione (6a), 6-(5-fluoro-2-hydroxybenzoyl)-1-methylpyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione (6b), 6-(5-ethyl-2-hydroxybenzoyl)-1-methylpyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione (6c) and 6-(2-hydroxy-5-isopropylbenzoyl)-1-methylpyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione (6d). The chemical structures of the title compounds were ascertained by spectral techniques including ¹H, ¹³C NMR, UV-visible and FT-IR spectroscopy as well as single-crystal X-ray diffraction analysis. Additionally, density functional theory (DFT) and time-dependent (TD-DFT) computation were adopted to analyze the electronic structures of 6a-d. Compounds 6a-d were computed in the ground state for FT-IR spectroscopic and natural bond orbital (NBO) analysis by DFT/B3LYP with the 6-311+G(d,p) basis set. UV-vis spectroscopic and HOMO and LUMO energy values for 6a-d were determined via TD-DFT/B3LYP with the 6-311+G(d,p) basis set. The optimized geometric parameters, UV-vis findings, and vibrational frequencies indicate good consistency with the experimental data. NBO analysis was conducted to explore the interactions and charge transfer among different orbitals in the title compounds. The HOMO and LUMO band gap (ΔE) values for 6a-d were found to be 3.93, 3.91, 4.10 and 3.91 eV, respectively. Molecular electrostatic potential (MEP) analysis explored the reactivity of the title compounds by predicting their nucleophilic as well as electrophilic sites.

Cytotoxicity, oxidative stress, and apoptosis in K562 leukemia cells induced by an active compound from pyrano-pyridine derivatives

Recent studies have reported the potential of pyrano-pyridine compounds in inhibiting cell growth and apoptosis induction in cancer cells. Here, we investigated the effect of new pyrano-pyridine derivatives on proliferation, oxidative damages, and apoptosis in K562 leukemia cells. Among different tested compounds, we found 8-(4-chlorobenzylidene)-2-amino-4-(4-chlorophenyl)-5, 6, 7, 8-tetrahydro-6-phenethyl-4H-pyrano-[3,2-c]pyridine-3-carbonitrile (4-CP.P) as the most effective compound with IC50 value of 20 μM. Gel electrophoresis, fluorescence microscopy, and flow cytometry analyses indicated the apoptosis induction ability of 4-CP.P in K562 cells. Further analyses revealed that 4-CP.P induces significant increase in cellular reactive oxygen species production, lipid peroxidation, protein oxidation, and total thiol depletion. Interestingly, while 4-CP.P significantly increased the activity of superoxide dismutase, it reduced the catalase activity in a time-dependent manner. These data propose that 4-CP.P treatment causes free radicals accumulation that ultimately leads to oxidative stress condition and apoptosis induction. Therefore, we report the 4-CP.P as a novel, potent compound as a chemotherapeutic agent in cancer treatment.

The effect of newly synthesized progesterone derivatives on apoptotic and angiogenic pathway in MCF-7 breast cancer cells

Due to its high potency and selectivity, anticancer agents consisting of combined molecules have gained great interests. The current study introduces newly synthesized progesterone derivatives of promising anticancer effect. Moreover, the pro-apoptotic and anti-angiogenic effects of these compounds were studied extensively. Several thiazole, pyridine, pyrazole, thiazolopyridine and pyrazolopyridine progesterone derivatives were synthesized. The structure of the novel progesterone derivatives was elucidated and confirmed using the analytical and spectral data. This novel derivatives were tested for their cytotoxic effect against human breast cancer cells (MCF-7) using neutral red uptake assay. Tested compounds showed anticancer activity against MCF-7 cancer cell line in the descending order of 7>2>3>8>6>9>4. The expression levels of Bcl-2, survivin, CCND1, CDC2, P53 and P21, VEGF, Hif-1α, MMP-2, MMP-9, Ang-1, Ang-2, and FGF-1 genes were investigated using QRT-PCR (Quantitative real time-polymerase chain reaction). The study clarified that compounds 2, 3, 4, 6, 7, 8 and 9 showed significant pro-apoptotic effect through the down regulation of Bcl-2., besides, survivin and CCND1 expression levels were down regulated by compounds 3, 4, 6, 7, 8, 9. However, Compound 4 may exert this pro-apoptotic effect through the up-regulation of P53 gene expression. On the other hand, the anti-angiogenic effect of these newly synthesized derivatives was due to their down regulation of VEGF, Ang-2, MMP-9 and FGF-1; and the up-regulation of HIF-1α and ang-1. This study recommended promising pro-apoptotic and anti-angiogenic anticancer agents acting through the regulation of key regulators of apoptosis, cell cycle genes, and pro-angiogenic genes.

Synthesis of Some Polysubstituted Nicotinonitriles and Derived Pyrido[2,3-d]pyrimidines asIn VitroCytotoxic and Antimicrobial Candidates

The synthesis of polysubstituted pyridines, in addition to some derived pyrido[2,3-d]pyrimidine ring systems supported with chemotherapeutically active functionalities, is described. They were evaluated for theirin vitrocytotoxic effects against three different human tumor cell lines (human colon carcinoma HT29, hepatocellular carcinoma Hep-G2, and Caucasian breast adenocarcinoma MCF7). Nine compounds displayed variable cytotoxic potential, among which alkylthio analogs33,34, and37emerged as the most active members, being almost twice as active as doxorubicin against the colon carcinoma HT29 cell line. In addition, the same three analogs showed a clear differential cytotoxic profile as they exhibited a marginal inhibitory effect on the growth of the normal nontransformed human foreskin fibroblast Hs27 cell line. Meanwhile, nineteen compounds were able to exhibit significant antibacterial activity against both Gram-positive and Gram-negative bacteria, together with moderate antifungal activities. The pyrido[2,3-d]pyrimidine-2(1H)-thione30together with its alkylthio derivatives33and34stemmed as the most active antimicrobial members being equipotent to ampicillin againstS. aureus,E. coli,andP. aeruginosa,together with a noticeable antifungal activity againstC. albicans.Compounds33and34could be considered as a promising template for possible dual antimicrobial-anticancer candidates.

Rational design, synthesis and 2D-QSAR studies of antiproliferative tropane-based compounds

Novel tropane-based compounds were synthesized exhibiting antiproliferative properties against HepG2 and MCF7 carcinoma cell lines.

Crystal structures of 3,5-bis-[(E)-3-hy-droxy-benzyl-idene]-1-methyl-piperidin-4-one and 3,5-bis-[(E)-2-chloro-benzyl-idene]-1-methyl-piperidin-4-one

The title compounds, C20H19NO3, (1), and C20H17Cl2NO, (2), are the 3-hy-droxy-benzyl-idene and 2-chloro-benzyl-idene derivatives, respectively, of curcumin [systematic name: (1E,6E)-1,7-bis-(4-hy-droxy-3-meth-oxy-phen-yl)-1,6-hepta-diene-3,5-dione]. The dihedral angles between the benzene rings in each compound are 21.07 (6)° for (1) and 13.4 (3)° for (2). In both compounds, the piperidinone rings adopt a sofa confirmation and the methyl group attached to the N atom is in an equatorial position. In the crystal of (1), two pairs of O-H⋯N and O-H⋯O hydrogen bonds link the mol-ecules, forming chains along [10-1]. The chains are linked via C-H⋯O hydrogen bonds, forming undulating sheets parallel to the ac plane. In the crystal of (2), mol-ecules are linked by weak C-H⋯Cl hydrogen bonds, forming chains along the [204] direction. The chains are linked along the a-axis direction by π-π inter-actions [inter-centroid distance = 3.779 (4) Å]. For compound (2), the crystal studied was a non-merohedral twin with the refined ratio of the twin components being 0.116 (6):0.886 (6).

Synthesis and biological evaluation of some novel urea and thiourea derivatives of isoxazolo[4,5-d]pyridazine and structurally related thiazolo[4,5-d]pyridazine as antimicrobial agents

This study reports the synthesis of some novel isoxazolo[4,5-d]pyridazines and structurally related thiazolo[4,5-d]pyridazines, and their biological evaluation as antimicrobial agents. The proposed compounds were designed to contain pharmacophores such as urea, thiourea, sulfonylurea (thiourea) and some derived functionalities that are believed to contribute to the anticipated biological activities. The results revealed that 25 compounds displayed broad spectrum of antibacterial activity, with greater inhibitory effect on the growth of the tested Gram positive strains compared to Gram negative ones. Moreover, 14 compounds were able to produce appreciable growth inhibitory activity against Candida albicans fungus when compared to Clotrimazole. Most of the tested isoxazolo[4,5-d]pyridazines displayed better antimicrobial profile than their corresponding thiazolo[4,5-d]pyridazine congeners. Four compounds namely, p-(3,7-dimethyl-4-oxo-4H-isoxazolo [4,5-d]pyridazine-5-yl)benzenesulfonylthioureas (11c-d), 3-substituted-2-[p-(3,7-dimethyl-4-oxo-4H-isoxazolo[4,5-d]pyridazine-5-yl)-benzene-sufonylimino]-4-oxothiazolidines (13d) and p-(2,7-dimethyl-4-oxo-4H-thiazolo[4,5-d]pyridazin-5-yl)benzenesulfonylthiourea (24c) were found to be most active antimicrobial members in present study.

A green expedient synthesis of pyridopyrimidine-2-thiones and their antitubercular activity

The pseudo four-component domino reactions of N-substituted-4-piperidones, substituted aromatic aldehydes and thiourea in the presence of solid sodium ethoxide under solvent-free conditions afforded pyridopyrimidine-2-thiones in almost quantitative yields by simply grinding for 1-2 min. at ambient temperature. The synthesized compounds were screened for their in vitro activity against Mycobacterium tuberculosis H37Rv. Among them, (E)-6-benzyl-8-(2,4-dichlorobenzylidene)-4-(2,4-dichlorophenyl)-3,4,5,6,7,8-hexahydropyrido[4,3-d]pyrimidine-2(1H)-thione (MIC 2.8 μM) displays the maximum activity, being 2.7 and 1.7 times more active than the first line antitubercular drugs ethambutol and ciprofloxacin, respectively, and less active than rifampicin and isoniazid, by 28 and 7 times, respectively.

Synthesis and cytotoxic potential of heterocyclic cyclohexanone analogues of curcumin

A series of 18 heterocyclic cyclohexanone analogues of curcumin have been synthesised and screened for their activity in both adherent and non-adherent cancer cell models. Cytotoxicity towards MBA-MB-231 breast cancer cells, as well as ability to inhibit NF-kappaB transactivation in non-adherent K562 leukemia cells were investigated. Three of these analogues 3,5-bis(pyridine-4-yl)-1-methylpiperidin-4-one B1, 3,5-bis(3,4,5-trimethoxybenzylidene)-1-methylpiperidin-4-one B10, and 8-methyl-2,4-bis((pyridine-4-yl)methylene)-8-aza-bicyclo[3.2.1]octan-3-one C1 showed potent cytotoxicity towards MBA-MB-231, MDA-MB-468, and SkBr3 cell lines with EC50 values below 1 microM and inhibition of NF-kappaB activation below 7.5 microM. The lead drug candidate, B10, was also able to cause 43% of MDA-MB-231 cells to undergo apoptosis after 18 h. This level of activity warrants further investigation for the treatment of ER-negative breast cancer and/or chronic myelogenous leukemia as prototypical cellular models for solid and liquid tumors.