Novel 2-(2-arylmethylthio-4-chloro-5-methylbenzenesulfonyl)-1-(1,3,5-triazin-2-ylamino)guanidine derivatives: Inhibition of human carbonic anhydrase cytosolic isozymes I and II and the transmembrane tumor-associated isozymes IX and XII, anticancer activity, and molecular modeling studies

Unraveling the mechanism of carbonic anhydrase IX inhibition by alkaloids from Ruta chalepensis: A synergistic analysis of in vitro and in silico data

Due to the pivotal role of carbonic anhydrase IX (CA IX) in pathological conditions, there's a pressing need for novel inhibitors to improve patient outcomes and clinical management. Herein, we investigated the inhibitory efficacy of six alkaloids from Ruta chalepensis against CA IX through in vitro inhibition assay and computational modeling. Skimmianine and maculosidine displayed significant inhibitory activity in vitro, with low IC50 values of 105.2 ± 3.2 and 295.7 ± 14.1 nM, respectively. Enzyme kinetics analyses revealed that skimmianine exhibited a mixed inhibition mode, contrasting with the noncompetitive inhibition mechanism observed for the reference drug (acetazolamide), as indicated by intersecting lines in the Lineweaver-Burk plots. The findings of docking calculations revealed that skimmianine and maculosidine exhibited extensive polar interactions with the enzyme. These alkaloids demonstrate substantial binding interactions and occupy identical binding site as acetazolamide, thereby enhancing their efficacy as inhibitors of CA IX. Utilizing a 100 ns molecular dynamics (MD) simulation, the dynamic interactions between isolated alkaloids and CA IX were intensively assessed. Analysis of diverse MD parameters revealed that skimmianine and maculosidine displayed consistent trajectories and notable energy stabilization during their interaction with CA IX. The findings of MM/PBSA analysis depicted the minimum binding free energy for skimmianine and maculosidine. In addition, the Potential Energy Landscape (PEL) analysis revealed distinct and stable conformational states for the CA IX-ligand complexes, with Skimmianine showing the most stable and lowest energy configuration. These computational findings align with experimental results, emphasizing the potential efficacy of skimmianine and maculosidine as inhibitors of CA IX.

Synthetic and pharmacological developments in the hybrid s-triazine moiety: A review

This article summarizes the most recent advancements in the synthetic and pharmacological approaches along with the structure activity relationship towards the s-triazine and its derivatives. Much attention has been given to s-triazine core due to its facile synthesis, interesting pharmacology, high reactivity, and binding characteristics towards various enzymes. An array of biological applications has been demonstrated by s-triazines including antimalarial, anti-HIV, anti-viral, antimicrobial, anti-tuberculosis to name a few. In the present investigation s-triazine based molecular structures have been assembled in respect to their synthesis and medicinal properties. Further, the competence of s-triazine has been correlated and compared with the other heterocyclic moieties to substantiates-triazine a privileged scaffold. From the literature it is revealed that nucleophilic substitution at 2, 4, and 6 positions is significant for various biological applications. This article would help in assisting the chemists in designing novel molecular entities with high medicinal value.

An In Vitro Antimicrobial, Anticancer and Antioxidant Activity of N–[(2–Arylmethylthio)phenylsulfonyl]cinnamamide Derivatives

Cinnamic acid is a plant metabolite with antimicrobial, anticancer, and antioxidant properties. Its synthetic derivatives are often more effective in vitro than parent compounds due to stronger biological activities. In our study, we synthesized ten new N–(4–chloro–2–mercapto–5–methylphenylsulfonyl)cinnamamide derivatives, containing two pharmacophore groups: cinnamic acid moiety and benzenesulfonamide. The antimicrobial activity of the obtained compounds was estimated using different types of Gram-positive and Gram-negative bacteria, fungus species of Candida albicans, as well as clinical strains. The compounds were evaluated on biofilm formation and biofilm formed by Staphylococcus clinical strains (methicillin–resistance S. aureus MRSA and methicillin–resistance coagulase–negative Staphylococcus MRCNS). Furthermore, blood bacteriostatic activity test was performed using S. aureus and S. epidermidis. In cytotoxic study, we performed in vitro hemolysis assay on domestic sheep peripheral blood and MTT [3–(4,5–dimethylthiazol–2–yl)–2,5–diphenyltetrazolium bromide] assay on human cervical HeLa, ovarian SKOV-3, and breast MCF-7 cancer cell lines. We also estimated antioxidant activity of ten compounds with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′–azino–bis(3–ethylbenzthiazoline–6–sulfonic acid) (ABTS) assays. Our results showed a significant antimicrobial activity of the compounds. All of them were active on Staphylococcus and Enterococcus species (MIC was 1–4 µg/mL). The compounds 16d and 16e were the most active on staphylococci clinical strains and efficiently inhibited the biofilm formation and biofilm already formed by the clinical staphylococci. Moreover, the hemolytic properties of the tested compounds occurred in higher quantities (>32.5 µg/mL) than the concentrations that inhibited both the growth of bacteria in the blood and the formation and growth of biofilm. The results of MTT assay showed that compounds 16c, 16d, 17a, and 17d demonstrated the best activity on the cancer cells (the IC50 values were below 10 µg/mL). Compound 16f was the least active on the cancer cells (IC50 was > 60 µg/mL). Antiradical tests revealed that compounds 16f and 17d had the strongest antioxidant properties within the tested group (IC50 was 310.50 ± 0.73 and 574.41 ± 1.34 µg/mL in DPPH, respectively, and 597.53 ± 1.3 and 419.18 ± 2.72 µg/mL in ABTS assay, respectively). Our study showed that the obtained cinnamamide derivatives can be used as potential antimicrobial therapeutic agents.

Recent updates on 1,2,3-, 1,2,4-, and 1,3,5-triazine hybrids (2017-present): The anticancer activity, structure-activity relationships, and mechanisms of action

Cancer is one of the leading causes of death across the world, and the prevalence and mortality rates of cancer will continue to grow. Chemotherapeutics play a critical role in cancer therapy, but drug resistance and side effects are major hurdles to effective treatment, evoking an immediate need for the discovery of new anticancer agents. Triazines including 1,2,3-, 1,2,4-, and 1,3,5-triazine have occupied a propitious place in drug design and development due to their excellent pharmacological profiles. Mechanistically, triazine derivatives could interfere with various signaling pathways to induce cancer cell death. Hence, triazine derivatives possess potential in vitro and in vivo efficacy against diverse cancers. In particular, triazine hybrids are able to overcome drug resistance and reduce side effects. Moreover, several triazine hybrids such as brivanib (indole-containing pyrrolo[2,1-f][1,2,4]triazine), gedatolisib (1,3,5-triazine-urea hybrid), and enasidenib (1,3,5-triazine-pyridine hybrid) have already been available in the market. Accordingly, triazine hybrids are useful scaffolds for the discovery of novel anticancer chemotherapeutics. This review focuses on the anticancer activity of 1,2,3-, 1,2,4-, and 1,3,5-triazine hybrids, together with the structure-activity relationships and mechanisms of action developed from 2017 to the present. The enriched structure-activity relationships may be useful for further rational drug development of triazine hybrids as potential clinical candidates.

Synthesis of 3-(2-Alkylthio-4-chloro-5-methylbenzenesulfonyl)-2-(1-phenyl-3-arylprop-2-enylideneamino)guanidine Derivatives with Pro-Apoptotic Activity against Cancer Cells

The untypical course of reaction between chalcones and benzenesulfonylaminoguanidines led to the new 3-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-2-(1-phenyl-3-arylprop-2-enylideneamino)guanidine derivatives 8-33. The new compounds were tested in vitro for their impact on the growth of breast cancer cells MCF-7, cervical cancer cells HeLa and colon cancer cells HCT-116 by MTT assay. The results revealed that the activity of derivatives is strongly related to the presence of hydroxy group in the benzene ring at the 3-arylpropylidene fragment. The most cytotoxic compounds 20 and 24 displayed mean IC₅₀ values of 12.8 and 12.7 μM, respectively, against three tested cell lines and were almost 3- and 4-fold more active toward MCF-7 and HCT-116 when compared with non-malignant HaCaT cells. Furthermore, compound 24 induced apoptosis in cancer cells and caused a decrease of mitochondrial membrane potential as well as an increase of cells in sub-G1 phase in contrast to its inactive analog 31. The strongest activity against the most sensitive HCT-116 cell line was found for compound 30 (IC₅₀ = 8 μM), which was 11-fold more effective in the growth inhibition of HCT-116 cells than those of HaCaT cells. Based on this fact, the new derivatives may be promising leading structures for the search for agents for the treatment of colon cancer.

New Benzimidazole-, 1,2,4-Triazole-, and 1,3,5-Triazine-Based Derivatives as Potential EGFRWT and EGFRT790M Inhibitors: Microwave-Assisted Synthesis, Anticancer Evaluation, and Molecular Docking Study

A new series of benzimidazole, 1,2,4-triazole, and 1,3,5-triazine derivatives were designed and synthesized using a microwave irradiation synthetic approach utilizing 2-phenylacetyl isothiocyanate (1) as a key starting material. All the new analogues were evaluated as anticancer agents against a panel of cancer cell lines utilizing doxorubicin as a standard drug. Most of the tested derivatives exhibited selective cytotoxic activity against MCF-7 and A-549 cancer cell lines. Furthermore, the new target compounds 5, 6, and 7 as the most potent antiproliferative agents have been assessed as in vitro EGFRWT and EGFRT790M inhibitors compared to the reference drugs erlotinib and AZD9291. They represented more potent suppression activity against the mutated EGFRT790M than the wild-type EGFRWT. Moreover, the compounds 5, 6, and 7 down-regulated the oncogenic parameter p53 ubiquitination. A docking simulation of compound 6b was carried out to correlate its molecular structure with its significant EGFR inhibition potency and its possible binding interactions within the active site of EGFRWT and the mutant EGFRT790M.

Recent Advances in the Biological Activity of s-Triazine Core Compounds

An effective strategy for successful chemotherapy relies on creating compounds with high selectivity against cancer cells compared to normal cells and relatively low cytotoxicity. One such approach is the discovery of critical points in cancer cells, i.e., where specific enzymes that are potential therapeutic targets are generated. Triazine is a six-membered heterocyclic ring compound with three nitrogen replacing carbon-hydrogen units in the benzene ring structure. The subject of this review is the symmetrical 1,3,5-triazine, known as s-triazine. 1,3,5-triazine is one of the oldest heterocyclic compounds available. Because of its low cost and high availability, it has attracted researcher attention for novel synthesis. s-Triazine has a weak base, it has much weaker resonance energy than benzene, therefore, nucleophilic substitution is preferred to electrophilic substitution. Heterocyclic bearing a symmetrical s-triazine core represents an interesting class of compounds possessing a wide spectrum of biological properties such as anti-cancer, antiviral, fungicidal, insecticidal, bactericidal, herbicidal and antimicrobial, antimalarial agents. They also have applications as dyes, lubricants, and analytical reagents. Hence, the group of 1,3,5-triazine derivatives has developed over the years. Triazine is not only the core amongst them, but is also a factor increasing the kinetic potential of the entire derivatives. Modifying the structure and introducing new substituents makes it possible to obtain compounds with broad inhibitory activity on processes such as proliferation. In some cases, s-triazine derivatives induce cell apoptosis. In this review we will present currently investigated 1,3,5-triazine derivatives with anti-cancer activities, with particular emphasis on their inhibition of enzymes involved in the process of tumorigenesis.

Synthesis, biological evaluation, and in silico studies of novel chalcone- and pyrazoline-based 1,3,5-triazines as potential anticancer agents

A novel series of triazin-chalcones (7,8)a-g and triazin-N-(3,5-dichlorophenyl)pyrazolines (9,10)a-g were synthesized and evaluated for their anticancer activity against nine different cancer strains. Triazine ketones 5 and 6 were synthesized from the cyanuric chloride 1 by using stepwise nucleophilic substitution of the chlorine atom. These ketones were subsequently subjected to a Claisen-Schmidt condensation reaction with aromatic aldehydes affording chalcones (7,8)a-g. Then, N-(3,5-dichlorophenyl)pyrazolines (9,10)a-g were obtained by cyclocondensation reactions of the respective chalcones (7,8)a-g with 3,5-dichlorophenylhydrazine. Among all the evaluated compounds, chalcones 7d,g and 8g exhibited more potent in vitro anticancer activity, with outstanding GI50 values ranging from 0.422 to 14.9 μM and LC50 values ranging from 5.08 μM to >100 μM. In silico studies, for both ligand- and structure-based, were executed to explore the inhibitory nature of chalcones and triazine derivatives. The results suggested that the evaluated compounds could act as modulators of the human thymidylate synthase enzyme.

Progress in the development of human carbonic anhydrase inhibitors and their pharmacological applications: Where are we today?

Carbonic anhydrases (CAs, EC 4.2.1.1) are widely distributed metalloenzymes in both prokaryotes and eukaryotes. They efficiently catalyze the reversible hydration of carbon dioxide to bicarbonate and H⁺  ions and play a crucial role in regulating many physiological processes. CAs are well-studied drug target for various disorders such as glaucoma, epilepsy, sleep apnea, and high altitude sickness. In the past decades, a large category of diverse families of CA inhibitors (CAIs) have been developed and many of them showed effective inhibition toward specific isoforms, and effectiveness in pathological conditions in preclinical and clinical settings. The discovery of isoform-selective CAIs in the last decade led to diminished side effects associated with off-target isoforms inhibition. The many new classes of such compounds will be discussed in the review, together with strategies for their development. Pharmacological advances of the newly emerged CAIs in diseases not usually associated with CA inhibition (neuropathic pain, arthritis, cerebral ischemia, and cancer) will also be discussed.

Synthesis, Anticancer Evaluation and Structure-Activity Analysis of Novel (E)- 5-(2-Arylvinyl)-1,3,4-oxadiazol-2-yl)benzenesulfonamides

To learn more about the structure-activity relationships of (E)-3-(5-styryl-1,3,4-oxadiazol-2-yl)benzenesulfonamide derivatives, which in our previous research displayed promising in vitro anticancer activity, we have synthesized a group of novel (E)-5-[(5-(2-arylvinyl)-1,3,4-oxadiazol-2-yl)]-4-chloro-2-R1-benzenesulfonamides 7-36 as well as (E)-4-[5-styryl1,3,4-oxadiazol-2-yl]benzenesulfonamides 47-50 and (E)-2-(2,4-dichlorophenyl)-5-(2-arylvinyl)-1,3,4-oxadiazols 51-55. All target derivatives were evaluated for their anticancer activity on HeLa, HCT-116, and MCF-7 human tumor cell lines. The obtained results were analyzed in order to explain the influence of a structure of the 2-aryl-vinyl substituent and benzenesulfonamide scaffold on the anti-tumor activity. Compound 31, bearing 5-nitrothiophene moiety, exhibited the most potent anticancer activity against the HCT-116, MCF-7, and HeLa cell lines, with IC50 values of 0.5, 4, and 4.5 µM, respectively. Analysis of structure-activity relationship showed significant differences in activity depending on the substituent in position 3 of the benzenesulfonamide ring and indicated as the optimal meta position of the sulfonamide moiety relative to the oxadizole ring. In the next stage, chemometric analysis was performed basing on a set of computed molecular descriptors. Hierarchical cluster analysis was used to examine the internal structure of the obtained data and the quantitative structure-activity relationship (QSAR) analysis with multiple linear regression (MLR) method allowed for finding statistically significant models for predicting activity towards all three cancer cell lines.

Continued exploration and tail approach synthesis of benzenesulfonamides containing triazole and dual triazole moieties as carbonic anhydrase I, II, IV and IX inhibitors

A library of twenty two novel 1,2,3-triazole benzenesulfonamides incorporating thiosemicarbazide, 5(4H)-thione-1,2,4-triazole and variously substituted phenacyl appended 1,2,4-triazole as tail were designed, synthesized and assessed for their efficacy as inhibitors against carbonic anhydrase human (h) isoforms hCA I, II, IV and IX. The physiologically important and off-target cytosolic isoform hCA I was weakly inhibited by most of the newly synthesized sulfonamides while the glaucoma associated isoform hCA II was moderately inhibited with KIs spanning in low nanomolar range (KI = 8.0 nM-0.903 μM). The membrane bound isoform hCA IV, which is known to be involved in glaucoma and retinitis pigmentosa among others, was strongly inhibited by all newly synthesized sulfonamides out of which nine compounds inhibited isoform hCA IV even more effectively as compared to standard drug acetazolamide (AAZ). The membrane bound isoform hCA IX, associated with growth of tumor cells, was moderately inhibited with KIs ranging between 51 nM-3.198 μM. The effect of appending variously substituted tails on heterocyclic moieties over inhibition potential of synthesized sulfonamides is also disclosed which can be of further interest in pharmacological studies for exploring synthesis of isoform selective inhibitors.

Synthetic approaches and pharmaceutical applications of chloro-containing molecules for drug discovery: A critical review

At present more than 250 FDA approved chlorine containing drugs were available in the market and many pharmaceutically important drug candidates in pre-clinical trials. Thus, it is quite obvious to expect that in coming decades there will be an even greater number of new chlorine-containing pharmaceuticals in market. Chlorinated compounds represent the family of compounds promising for use in medicinal chemistry. This review describes the recent advances in the synthesis of chlorine containing heterocyclic compounds as diverse biological agents and drugs in the pharmaceutical industries for the inspiration of the discovery and development of more potent and effective chlorinated drugs against numerous death-causing diseases.

Design, synthesis, and biological evaluation of polyphenols with 4,6-diphenylpyrimidin-2-amine derivatives for inhibition of Aurora kinase A

BACKGROUND

Several 4,6-diarylpyrimidin-2-amine derivatives show anticancer properties. However, their mode of action is not fully characterized. To develop potent anticancer chemotherapeutic agents, we designed and synthesized 25 4,6-diphenylpyrimidin-2-amine derivatives containing a guanidine moiety.

METHODS

Clonogenic long-term survival assays were performed to screen anticancer compounds. To derive the structural conditions showing good cytotoxicities against cancer cells, quantitative structure-activity relationships (QSAR) were calculated. Biological activities were determined by flow cytometry for cell cycle analysis and by immunoblot analysis for the detection of Aurora kinase A (AURKA) activity. Because 2-(2-Amino-6-(2,4-dimethoxyphenyl)pyrimidin-4-yl) phenol (derivative 12) selectively inhibited AURKA activity from the kinome assay, in silico docking experiments were performed to elucidate the molecular binding mode between derivative 12 and AURKA.

RESULTS

The pharmacophores were derived based on the QSAR calculations. Derivative 12 inhibited AURKA activity and reduced phosphorylation of AURKA at Thr283 in HCT116 human colon cancer cells. Derivative 12 caused the accumulation of the G2/M phase of the cell cycle and triggered the cleavages of caspase-3, caspase -7, and poly(ADP-ribose) polymerase. The binding energies of 30 apo-AURKA - derivative 12 complexes obtained from in silico docking ranged from -16.72 to -11.63 kcal/mol.

CONCLUSIONS

Derivative 12 is an AURKA inhibitor, which reduces clonogenicity, arrests the cell cycle at the G2/M phase, and induces caspase-mediated apoptotic cell death in HCT116 human colon cancer cells. In silico docking demonstrated that derivative 12 binds to AURKA well. The structure-activity relationship calculations showed hydrophobic substituents and 1-naphthalenyl group at the R2 position increased the activity. The existence of an H-bond acceptor at C-2 of the R1 position increased the activity, too. Graphical abstract Derivative 12 inhibits Aurora kinase A activity and causes the G2/M phase arrest of the cell cycle.

Synthesis, X-Ray Crystal Structures, and Preliminary Antiproliferative Activities of New s-Triazine-hydroxybenzylidene Hydrazone Derivatives

We herein report a new small library of Schiff-base compounds that encompasses s-triazine and (2 or 4)-hydroxylbenzylidene derivatives. These compounds were synthesized through a hydrazone linkage connecting both the s-triazine and hydroxybenzylidene derivatives. The synthetic strategy adopted allowed the synthesis of the target compounds with excellent yields and purities as observed from their NMR (1H and 13C) and elemental analysis. Furthermore, 4f, 5b, and 5f were further confirmed by X-ray single crystal diffraction technique. The preliminary antiproliferative activities for the synthesized compounds were tested against two different cancer cell lines including breast cancer (MCF-7) and colon cancer (HCT-116). From the eighteen compounds, which have been examined, only two derivatives having piperidine moiety showed more selectivity against the two cell lines MCF-7 and HCT-116, while the others showed very weak activity. The position of the hydroxyl group in the benzylidine ring and the substituent on the s-triazine moiety has great effect on the activity of the prepared compounds. The IC50 values for the two derivatives 4a and 5a evaluated against breast cancer cells, very close to those for the chemotherapeutic drug cisplatin, are 27 µM (13.3 µg/mL), 17 µM (8.4 µg/mL), and 20 µM (6 µg/mL) for 4a, 5a, and cisplatin, respectively. These results propose the preliminary antiproliferative activity of these two derivatives may deserve further consideration for development of new derivatives as potent anticancer agents.

Development of a Fingerprint-Based Scoring Function for the Prediction of the Binding Mode of Carbonic Anhydrase II Inhibitors

Carbonic anhydrase II (CAII) is a zinc-containing metalloenzyme whose aberrant activity is associated with various diseases such as glaucoma, osteoporosis, and different types of tumors; therefore, the development of CAII inhibitors, which can represent promising therapeutic agents for the treatment of these pathologies, is a current topic in medicinal chemistry. Molecular docking is a commonly used tool in structure-based drug design of enzyme inhibitors. However, there is still a need for improving docking reliability, especially in terms of scoring functions, since the complex pattern of energetic contributions driving ligand–protein binding cannot be properly described by mathematical functions only including approximated energetic terms. Here we report a novel CAII-specific fingerprint-based (IFP) scoring function developed according to the ligand–protein interactions detected in the CAII-inhibitor co-crystal structures of the most potent CAII ligands. Our IFP scoring function outperformed the ability of Autodock4 scoring function to identify native-like docking poses of CAII inhibitors and thus allowed a considerable improvement of docking reliability. Moreover, the ligand–protein interaction fingerprints showed a useful application in the binding mode analysis of structurally diverse CAII ligands.

Synthesis, molecular structure, and metabolic stability of new series of N'-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-1-(5-phenyl-1H-pyrazol-1-yl)amidine as potential anti-cancer agents

A series of new N'-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-1-(5-phenyl-1H-pyrazol-1-yl)amidine derivatives have been synthesized and evaluated in vitro by MTT assays for their antiproliferative activity against cell lines of colon cancer HCT-116, cervical cancer HeLa and breast cancer MCF-7. The studied compounds display selective activity mainly against HCT-116 and HeLa cells. Thus, five compounds show selective cytotoxic effect against HCT-116 (IC₅₀ = 3-10 μM) and HeLa (IC₅₀ = 7 μM). Importantly, the noticed values of IC₅₀ for four compounds are almost 4-fold lower for HeLa than non-malignant HaCaT cells. More-in-depth biological research revealed that the treatment of HCT-116 and HeLa with active compound resulted in increased numbers of cells in sub-G1 phase in a time dependent manner, while non-active derivative does not influence cell cycle. Metabolic stability assays using liver microsomes and NADPH provide important information on compounds susceptibility to phase 1 biotransformation reactions.

Synthesis of novel 4-functionalized 1,5-diaryl-1,2,3-triazoles containing benzenesulfonamide moiety as carbonic anhydrase I, II, IV and IX inhibitors

The design, synthesis and biological evaluation of a library of 1,2,3-triazole carboxylates incorporating carboxylic acid, hydroxymethyl, carboxylic acid hydrazide, carboxamide and benzenesulfonamide moieties is disclosed. All the novel compounds were investigated for their inhibition potential against carbonic anhydrase (CA, EC 4.2.1.1) human (h) isoforms hCA I, II, IV and IX, well established drug targets. The cytosolic isoform hCA I was inhibited with Ki's ranging between 53.2 nM and 7.616 μM whereas the glaucoma associated cytosolic isoform hCA II was inhibited with Ki's in the range 21.8 nM-0.807 μM. The membrane bound isoform hCA IV, involved in glaucoma and retinitis pigmentosa among others, was effectively inhibited by some of these compounds with Ki < 60 nM, better than the reference drug acetazolamide (AAZ). The tumor associated isoform hCA IX, a recently validated antitumor/antimetastatic drug target, was also effectively inhibited by some of the new sulfonamides, which possess thus the potential to be used as tools for exploring in more details the selective inhibition of hCAs involved in various pathologies.