Synthesis and cytotoxic activities of some pyrazoline derivatives bearing phenyl pyridazine core as new apoptosis inducers

Evaluation of Novel Spiro-pyrrolopyridazine Derivatives as Anticancer Compounds: In Vitro Selective Cytotoxicity, Induction of Apoptosis, EGFR Inhibitory Activity, and Molecular Docking Analysis

Cancer, characterized by uncontrolled cell proliferation, remains a global health challenge. Despite advancements in cancer treatment, drug resistance and adverse effects on normal cells remain challenging. The epidermal growth factor receptor (EGFR), a transmembrane tyrosine kinase protein, is crucial in controlling cell proliferation and is implicated in various cancers. Here, the cytotoxic and apoptotic potential of 21 newly synthesized spiro-pyrrolopyridazine (SPP) derivatives was investigated on breast (MCF-7), lung (H69AR), and prostate (PC-3) cancer cells. XTT assay was used for cytotoxicity assessment. Flow cytometry and western blot (WB) analyses were conducted for apoptosis detection. Additionally, the EGFR inhibitory potential of these derivatives was evaluated via a homogeneous time-resolved fluorescence (HTRF) assay, and WB and molecular docking studies were conducted to analyze the binding affinities of SPP10 with EGFR. SPPs, especially SPP10, exhibit significant cytotoxicity across MCF-7, H69AR, and PC-3 cancer cells with IC50 values of 2.31 ± 0.3, 3.16 ± 0.8, and 4.2 ± 0.2 μM, respectively. Notably, SPP10 demonstrates selective cytotoxicity against cancer cells with a low impact on nontumorigenic cells (IC50 value: 26.8 ± 0.4 μM). Flow cytometric analysis demonstrated the potent induction of apoptotic cell death by SPP10 in all of the tested cancer cells. Western blot analysis revealed the involvement of key apoptotic proteins, with SPP10 notably inhibiting antiapoptotic Bcl-2 while inducing pro-apoptotic Bax and cytochrome c. SPP10 exhibited significant EGFR kinase inhibitory activity, surpassing the efficacy of the reference drug erlotinib. Molecular docking studies support these findings, revealing strong binding affinities of SPP10 with both wild-type and mutated EGFR. The study underscores the significance of heterocyclic compounds, particularly spiro-class heterocyclic molecules, in advancing cancer research. Overall, SPP10 emerges as a promising candidate for further investigations in cancer treatment, combining potent cytotoxicity, apoptotic induction, and targeted EGFR inhibition.

Utility of sulfachloropyridazine in the synthesis of novel anticancer agents as antiangiogenic and apoptotic inducers

In a search for new anticancer agents with better activity and selectivity, the present work described the synthesis of several new series of sulfachloropyridazine hybrids with thiocarbamates 3a-e, thioureids 4a-h, 5a-e and 4-substituted sulfachloropyridazines 6a, b, 7a, b and 8. The synthesized compounds were screened in vitro against a panel of 60 cancer cell lines in one dose assay. The most potent derivatives 3a, 3c, 4c, 4d, 5e, 7a and 7b were tested for their antiangiogenic activity by measuring their ability to inhibit VEGFR-2. The most potent compounds in VEGFR-2 inhibitory assay were further evaluated for their ability to inhibit PDGFR. In addition, the ability of 4c compound to inhibit cell migration on HUVEC cells and cell cycle effect on UO-31 cells has been studied. The pro-apoptotic effect of compound 4c was studied by the evaluation of caspase-3, Bax and BCl-2. Alternatively, the IC50 of compounds 3a, 3c, 4c, 5e, 7a and 7b against certain human cancer cell lines were determined. Re-evaluation in combination with γ-radiation was carried out for compounds 4c, 5e and 7b to study the possible synergistic effect on cytotoxicity. Docking studies of the most active compounds were performed to give insights into the binding mode within VEGFR-2 active site.

Tailored horseshoe-shaped nicotinonitrile scaffold as dual promising c-Met and Pim-1 inhibitors: Design, synthesis, SAR and in silico study

For the horseshoe tactic to succeed in inhibiting c-Met and Pim-1, the nicotinonitrile derivatives (2a-n) were produced in high quantities by coupling acetyl phenylpyrazole (1) with the proper aldehydes and ethyl cyanoacetate under basic conditions. Consistent basic and spectroscopic data (NMR, IR, Mass, and HPLC) supported the new products' structural findings. With IC50 potency in nanomolar ranges, these compounds had effectively repressed them, particularly compounds 2d and 2 h, with IC50 values below 200 nM. The most potent compounds (2d and 2 h) were tested for their antitumor effects against prostate (PC-3), colon (HCT-116), and breast (MDA-MB-231) and were evaluated in comparison to the anticancer drug tivantinib using the MTT assay. Similar to tivantinib, these compounds showed good antiproliferative properties against the HCT-116 tumor cells while having low cytotoxicity towards healthy fetal colon (FHC) cells. In the HCT-116 cell line, their ability to trigger the apoptotic cascade was also investigated by looking at the level of Bax and Bcl-2 as well as the activation of the proteolytic caspase cascade. When HCT-116 cells were exposed to compounds 2d and 2 h in comparison to the control, active caspase-3 levels increased. The HCT-116 cell line also upregulated Bcl-2 protein levels and downregulated Bax levels. Additionally, when treated with compound 2d, the HCT-116 cell cycle was primarily stopped at the S phase. Compared to the control, compound 2d treatment significantly inhibited the protein expression levels of c-Met and Pim-1 kinases in the treated HCT-116 cells. Thorough molecular modeling analyses, such as molecular docking and dynamic simulation, were performed to ascertain the binding mechanism and stability of the target compounds.

Discovery of Novel Pyridazine-Tethered Sulfonamides as Carbonic Anhydrase II Inhibitors for the Management of Glaucoma

As a progressive neuropathic condition, glaucoma can cause lifelong blindness if left untreated. Novel phenylpyridazine-tethered sulfonamides were designed as selective inhibitors for carbonic anhydrase (CA) isoform II to find effective therapeutic agents for glaucoma. Subsequently, the target inhibitors were synthesized and assessed for their inhibitory action against cytosolic CA I and II. Interestingly, the synthesized molecules poorly inhibited CA I while exhibiting low subnanomolar potency against CA II. Compound 7c disclosed the most potent activity (IC50 = 0.63 nM) with high selectivity against CA II (605-fold than acetazolamide selectivity). Moreover, compound 7c also showed significant in vivo IOP-reducing properties in the in vivo model of glaucoma. Furthermore, the binding of compound 7c to CA II was assessed at the molecular level, exploiting the molecular docking approach.

Diverse Pharmacological Potential of Pyridazine Analogs against Various Diseases

Pyridazinone analogs possess diverse types of pharmacological activities, such as anticancer, antimicrobial, anticonvulsant, analgesic, anti-inflammatory, antioxidant, antihypertensive, antisecretory, antiulcer, and other useful pharmacological activities. They also possess cyclooxygenase (COX) inhibitors, dipeptidyl peptidase inhibitors, phosphodiesterase inhibitors, glutamate transporter activators, adenosine receptor antagonists, serotonin receptors antagonists, lipooxygenase, cholinesterase, vasodilator, and anesthetics. Pyridazine rings are the essential structure for some marketed drugs, such as pimobendan, levosimendan as a cardiotonic drug, and emorfozan as an analgesic and anti-inflammatory (Non-steroidal anti-inflammatory drug) agent. So, researchers all over the world have paid attention to synthesizing various pyridazinone compounds mainly due to the ease of design and synthesis of different analogs and variables in the pharmacological responses. This review article focuses on the pharmacological activities of different pyridazine analogs.

Acetic Acid-Catalyzed (3 + 2) Cyclization of 2-Aroyl-3-aryl-1,1-dicyanocyclopropanes with Arylhydrazines: To trans-4-Dicyanomethyl-1,3,5-triaryl-4,5-dihydropyrazoles

Acetic acid-catalyzed (3 + 2) cyclization reaction of substituted 2-aroyl-3-aryl-1,1-dicyanocyclopropanes with arylhydrazines was investigated for the efficient synthesis of 4-dicyanomethyl-1,3,5-triaryl-4,5-dihydropyrazoles in good yields, in which 4,5-double substituents are predominantly trans selective. This approach included the consecutive condensation, ring opening, and double nucleophilic cyclization reaction.

Synthetic Approaches, Biological Activities, and Structure-Activity Relationship of Pyrazolines and Related Derivatives

It has been established that pyrazolines and their analogs are pharmacologically active scaffolds. The pyrazoline moiety is present in several marketed molecules with a wide range of uses, which has established its importance in pharmaceutical and agricultural sectors, as well as in industry. Due to its broad-spectrum utility, scientists are continuously captivated by pyrazolines and their derivatives to study their chemistry. Pyrazolines or their analogs can be prepared by several synthesis strategies, and the focus will always be on new greener and more economical ways for their synthesis. Among these methods, chalcones, hydrazines, diazo compounds, and hydrazones are most commonly applied under different reaction conditions for the synthesis of pyrazoline and its analogs. However, there is scope for other molecules such as Huisgen zwitterions, different metal catalysts, and nitrile imine to be used as starting reagents. The present article consists of recently reported synthetic protocols, pharmacological activities, and the structure-activity relationship of pyrazoline and its derivatives, which will be very useful to researchers.

Therapeutic significance of molecular hybrids for breast cancer research and treatment

Worldwide, breast cancer is still a leading cause of cancer death in women. Indeed, over the years, several anti-breast cancer drugs have been developed; however, the complex heterogeneous nature of breast cancer disease reduces the applicability of conventional targeted therapies with the upsurge in side effects and multi-drug resistance. Molecular hybrids generated by a combination of two or more active pharmacophores emerged as a promising approach in recent years for the design and synthesis of anti-breast cancer drugs. The hybrid anti-breast cancer molecules are well known for their several advantages compared to the parent moiety. These hybrid forms of anti-breast cancer molecules demonstrated remarkable effects in blocking different pathways contributing to the pathogenies of breast cancer and improved specificity. In addition, these hybrids are patient compliant with reduced side effects and multi-drug resistance. The literature revealed that molecular hybrids are applied to discover and develop novel hybrids for various complex diseases. This review article highlights the recent progress (∼2018-2022) in developing molecular hybrids, including linked, merged, and fused hybrids, as promising anti-breast cancer agents. Furthermore, their design principles, biological potential, and future perspective are discussed. The provided information will lead to the development of novel anti-breast cancer hybrids with excellent pharmacological profiles in the future.

Ligand-Based Design on the Dog-Bone-Shaped BIBR1532 Pharmacophoric Features and Synthesis of Novel Analogues as Promising Telomerase Inhibitors with In Vitro and In Vivo Evaluations

Telomerase is an outstanding biological target for cancer treatment. BIBR1532 is a non-nucleoside selective telomerase inhibitor; however, it experiences ineligible pharmacokinetics. Herein, we aimed to design new BIBR1532-based analogues as promising telomerase inhibitors. Therefore, two novel series of pyridazine-linked to cyclopenta[b]thiophene (8a-f) and tetrahydro-1-benzothiophene (9a-f) were synthesized. A quantitative real-time polymerase chain reaction was utilized to investigate the telomerase inhibitory activity of candidates. Notably, 8e and 9e exhibited the best inhibition profiles. Moreover, 8e showed strong antitumor effects against both MCF-7 and A549 cancer cell lines. The effects of 8e on the cell cycle and apoptosis were measured. Besides, 8e was evaluated for its in vivo antitumor activity using solid Ehrlich carcinoma. The reduction in both the tumor weight and volume was greater than doxorubicin. Also, molecular docking and ADME studies were performed. Finally, a SAR study was conducted to gain further insights into the different telomerase inhibition potentials upon variable structural modifications.

Design, synthesis, and biological evaluation of novel ciprofloxacin derivatives as potential anticancer agents targeting topoisomerase II enzyme

A series of novel ciprofloxacin (CP) derivatives substituted at the N-4 position with biologically active moieties were designed and synthesised. 14 compounds were 1.02- to 8.66-fold more potent than doxorubicin against T-24 cancer cells. Ten compounds were 1.2- to 7.1-fold more potent than doxorubicin against PC-3 cancer cells. The most potent compounds 6, 7a, 7b, 8a, 9a, and 10c showed significant Topo II inhibitory activity (83-90% at 100 μM concentration). Compounds 6, 8a, and 10c were 1.01- to 2.32-fold more potent than doxorubicin. Compounds 6 and 8a induced apoptosis in T-24 (16.8- and 20.1-fold, respectively compared to control). This evidence was supported by an increase in the level of apoptotic caspase-3 (5.23- and 7.6-fold, sequentially). Both compounds arrested the cell cycle in the S phase in T-24 cancer cells while in PC-3 cancer cells the two compounds arrested the cell cycle in the G1 phase. Molecular docking simulations of compounds 6 and 8a into the Topo II active site rationalised their remarkable Topo II inhibitory activity.

Rational Design, Synthesis and Biological Evaluation of Novel Pyrazoline-Based Antiproliferative Agents in MCF-7 Cancer Cells

Breast cancer is a disease in which cells in the breast divide continuously without control. There are great limitations in cancer chemotherapy. Hence, it is essential to search for new cancer therapeutics. Herein, a novel series of EGFR/HER2 dual inhibitors has been designed based on the hybridization of thiazole and pyrazoline fragments. The synthesized compounds were screened for their anti-proliferative activity against MCF-7 breast cancer cell line and MCF-10 normal breast cell line. Interestingly, synthesized compounds 6e and 6k showed very potent antiproliferative activity towards MCF-7 with IC50 values of 7.21 and 8.02 µM, respectively. Furthermore, enzymatic assay was performed against EGFR and HER2 to prove the dual inhibitory action. Compounds 6e and 6k showed potent inhibitory activity for EGFR with IC50 of 0.009 and 0.051 µM, respectively, and for HER2 with IC50 of 0.013 and 0.027 µM, respectively. Additionally, compounds 6e and 6k significantly stimulated apoptotic breast cancer cell death. Compound 6e was further explored for its anticancer activity in vivo using a Xenograft model. Moreover, computational modeling studies, ADMET studies and toxicity prediction were performed to investigate their potential drug candidates.

A medicinal chemist's perspective towards structure activity relationship of heterocycle based anti-cancer agents

AIM

To describe structure activity relationship of heterocyclic derivatives with multi-targeted anticancer activity.

OBJECTIVES

With the following goals in mind, this review tries to describe significant recent advances in the medicinal chemistry of heterocycle-based compounds: (1) To shed light on recent literature focused on heterocyclic derivatives' anticancer potential; (2) To discuss recent advances in the medicinal chemistry of heterocyclic derivatives, as well as their biological implications for cancer eradication; (3) To summarise the comprehensive correlation of structure activity relationship (SAR) with pharmacological outcomes in cancer therapy.

BACKGROUND

Cancer remains one of the major serious health issues devastating the world today. Cancer is a complex disease in which improperly altered cells proliferate at an uncontrolled, rapid, and severe rate. Variables such as poor dietary habits, high stress, age, and smoking, can all contribute to the development of cancer. Cancer can affect almost any organ or tissue, although the brain, breast, liver, and colon are the most frequently affected organs. From several years, surgical operations and irradiation are in use along with chemotherapy as a primary treatment of cancer but still effective treatment of cancer remains a huge challenge. Chemotherapy is now one of the most effective strategies to eradicate cancer, although it has been shown to have a number of cytotoxic and unfavourable effects on normal cells. Despite all of these cancer treatments, there are several other targets for anticancer drugs. Cancer can be effectively eradicated by focusing on these targets, which include both cell-specific and receptor-specific targets such as tyrosine kinase receptors (TKIs). Heterocyclic scaffolds also have a variety of applications in drug development and are a common moiety in the pharmaceutical, agrochemical, and textile industries.

METHODS

The association between structural activity relationship data of many powerful compounds and their anticancer potential in vitro and in vivo has been studied. SAR of powerful heterocyclic compounds can also be generated using molecular docking simulations, as reported vastly in literature.

CONCLUSIONS

Heterocycles have a wide range of applications, from natural compounds to synthesised derivatives with powerful anticancer properties. To avoid cytotoxicity or unfavourable effects on normal mammalian cells due to a lack of selectivity towards the target site, as well as to reduce the occurrence of drug resistance, safer anticancer lead compounds with higher potency and lower cytotoxicity are needed. This review emphasizes on design and development of heterocyclic lead compounds with promising anticancer potential.

Discovery of 3,6-disubstituted pyridazines as a novel class of anticancer agents targeting cyclin-dependent kinase 2: synthesis, biological evaluation and in silico insights

Human health in the current medical era is facing numerous challenges, especially cancer. So, the therapeutic arsenal for cancer should be unremittingly enriched with novel small molecules that selectively target tumour cells with minimal toxicity towards normal cells. In this context, herein a new series of 3,6-disubstituted pyridazines 11a–r has been synthesised and evaluated for in vitro anticancer activity. They possessed good anti-proliferative action towards human breast cancer T-47D (IC₅₀ range: 0.43 ± 0.01 − 35.9 ± 1.18 µM) and MDA-MB-231 (IC₅₀ range: 0.99 ± 0.03 − 34.59 ± 1.13 µM) cell lines, whereas they displayed weak activity against the tested ovarian cancer cell line SKOV-3. Among the studied compounds, the methyltetrahydropyran-bearing pyridazine 11m emerged as the unique submicromolar growth inhibitor herein reported towards both T-47D (IC₅₀ = 0.43 ± 0.01 µM) and MDA-MB-231 (IC₅₀ = 0.99 ± 0.03 µM) cell lines. In addition, the biological results indicated that pyridazines 11l and 11m exerted an efficient alteration within the cell cycle progression as well as induction of apoptosis in both T-47D and MDA-MB-231 cells. Moreover, pyridazines 11l and 11m displayed good mean tumour S. I. values of 13.7 and 16.1 upon assessment of their cytotoxicity towards non-tumorigenic breast MCF-10A cells. Furthermore, an in silico study proposed CDK2 as a probable enzymatic target for pyridazines 11, and explored their binding interactions within the vicinity of CDK2 binding site. Subsequently, pyridazines 11e, 11h, 11l, and 11m were selected to be evaluated for their ability to inhibit CDK2, where they exerted good inhibitory activity (IC₅₀ = 151, 43.8, 55.6 and 20.1 nM, respectively). Finally, the in silico study implied that target pyridazines 11 exhibited not only an efficient anticancer activity but also an acceptable ADME, physicochemical and druglikeness properties, specifically pyridazines 11l and 11m. Overall the obtained results from this study quite sustained our strategy and gave us a robust opportunity for further development and optimisation of 3,6-disubstituted pyridazine scaffold to enrich therapeutic arsenal with efficient and safe anticancer CDK inhibitors.

Pharmacophore hybridization approach to discover novel pyrazoline-based hydantoin analogs with anti-tumor efficacy

In search for new and safer anti-cancer agents, a structurally guided pharmacophore hybridization strategy of two privileged scaffolds, namely diaryl pyrazolines and imidazolidine-2,4-dione (hydantoin), was adopted resulting in a newfangled series of compounds (H1-H22). Herein, a bio-isosteric replacement of "pyrrolidine-2,5-dione" moiety of our recently reported antitumor hybrid incorporating diaryl pyrazoline and pyrrolidine-2,5-dione scaffolds with "imidazoline-2,4-dione" moiety has been incorporated. Complete biological studies revealed the most potent analog among all i.e. compound H13, which was at-least 10-fold more potent compared to the corresponding pyrrolidine-2,5-dione, in colon and breast cancer cells. In-vitro studies showed activation of caspases, arrest of G0/G1 phase of cell cycle, decrease in the expression of anti-apoptotic protein (Bcl-2) and increased DNA damage. In-vivo assay on HT-29 (human colorectal adenocarcinoma) animal xenograft model unveiled the significant anti-tumor efficacy along with oral bioavailability with maximum TGI 36% (i.p.) and 44% (per os) at 50 mg/kg dose. These findings confirm the suitability of hybridized pyrazoline and imidazolidine-2,4-dione analog H13 for its anti-cancer potential and starting-point for the development of more efficacious analogs.

Diastereoselective synthesis of functionalized tetrahydropyridazines containing indole scaffolds via an inverse-electron-demand aza-Diels–Alder reaction

A base-promoted and catalyst-free unprecedented inverse-electron-demand aza-Diels–Alder reaction between the in situ generated azoalkenes and 3-vinylindoles has been developed to afford tetrahydropyridazines containing indole scaffolds.

Recent Advances in the Synthesis of Pyrazole Derivatives

Pyrazole and its derivatives have gained wide attention in pharmaceutical, agrochemical and biological fields as well as in industry. They exhibit various biological activities such as anti-pyretic, anti-microbial, anti- inflammatory, anti-tumor, anti-viral, anti-histaminic, anti-convulsant, fungicidal, insecticidal, etc. In this review, we summarise the recent advances in the synthesis of pyrazole derivatives using various methodologies and covers literature from 2017-2020.

Pyridazine as a privileged structure: An updated review on anticancer activity of pyridazine containing bioactive molecules

Identification of potent anticancer agents with high selectivity and low toxicity remains on the way to human health. Pyridazine featuring advantageous physicochemical properties and antitumor potential usually is regarded as a central core in numerous anticancer derivatives. There are several approved pyridazine-based drugs in the market and analogues currently going through different clinical phases or registration statuses, suggesting pyridazine as a promising drug-like scaffold. The current review is intended to provide a comprehensive and updated overview of pyridazine derivatives as potential anticancer agents. In particular, we focused on their structure-activity relationship (SAR) studies, design strategies, binding modes and biological activities in the hope of offering novel insights for further rational design of more active and less toxic anticancer drugs.

Design and synthesis of pyrazole-pyrazoline hybrids as cancer-associated selective COX-2 inhibitors

In continuation of our previous work on cancer and inflammation, 15 novel pyrazole-pyrazoline hybrids (WSPP1-15) were synthesized and fully characterized. The formation of the pyrazoline ring was confirmed by the appearance of three doublets of doublets in ¹ H nuclear magnetic resonance spectra exhibiting an AMX pattern for three protons (H_A , H_M , and H_X ) of the pyrazoline ring. All the synthesized compounds were screened for their in vitro anticancer activity against five cell lines, that is, MCF-7, A549, SiHa, COLO205, and HepG2 cells, using the MTT growth inhibition assay. 5-Fluorouracil was taken as the positive control in the study. It was observed that, among them, WSPP11 was found to be active against A549, SiHa, COLO205, and HepG2 cells, with IC₅₀ values of 4.94, 4.54, 4.86, and 2.09 µM. All the derivatives were also evaluated for their cytotoxicity against HaCaT cells. WSPP11 was also found to be nontoxic against normal cells (cell line HaCaT), with an IC₅₀ value of more than 50 µM. The derivatives were also evaluated for their in vitro anti-inflammatory activity by the protein (egg albumin) denaturation assay and the red blood cell membrane stabilizing assay, using diclofenac sodium and celecoxib as standard. Compounds that showed significant anticancer and anti-inflammatory activities were further studied for COX-2 inhibition. The manifestation of a higher COX-2 selectivity index of WSPP11 as compared with other derivatives and an in vitro anticancer activity against four cell lines further established that compounds that were more selective toward COX-2 also exhibited a better spectrum of activity against various cancer cell lines.

Synthesis and Biological Evaluation of Pyrazoline and Pyrrolidine-2,5-dione Hybrids as Potential Antitumor Agents

In search of novel and effective antitumor agents, pyrazoline-substituted pyrrolidine-2,5-dione hybrids were designed, synthesized and evaluated in silico, in vitro and in vivo for anticancer efficacy. All the compounds exhibited remarkable cytotoxic effects in MCF7 and HT29 cells. The excellent antiproliferative activity toward MCF7 (IC₅₀ =0.78±0.01 μM), HT29 (IC₅₀ =0.92±0.15 μM) and K562 (IC₅₀ =47.25±1.24 μM) cell lines, prompted us to further investigate the antitumor effects of the best compound S2 (1-(2-(3-(4-fluorophenyl)-5-(p-tolyl)-4,5-dihydro-1H-pyrazol-1-yl)-2-oxoethyl)pyrrolidine-2,5-dione). In cell-cycle analysis, S2 was found to disrupt the growth phases with increased cell population in G₁ /G₀ phase and decreased cell population in G₂ /M phase. The excellent in vitro effects were also supported by inhibition of anti-apoptotic protein Bcl-2. In vivo tumor regression studies of S2 in HT29 xenograft nude mice, exhibited equivalent and promising tumor regression with maximum TGI, 66 % (i. p. route) and 60 % (oral route) at 50 mg kg^-1 dose by both the routes, indicating oral bioavailability and antitumor efficacy. These findings advocate that hybridization of pyrazoline and pyrrolidine-2,5-dioes holds promise for the development of more potent and less toxic anticancer agents.

Synthesis and biological evaluation of novel pyrazoline derivatives containing indole skeleton as anti-cancer agents targeting topoisomerase II

In order to develop potent anticaner agents, a novel series of 3-(1H-indol-3-yl)-2,3,3a,4-tetrahydrothiochromeno[4,3-c]pyrazole derivatives were synthesized. Structures of all compounds were confirmed. MTT assay has been employed to study antiproliferative activity of these compounds with four human cancer cell lines (MGC-803, Hela, MCF-7 and Bel-7404) and a normal cell line L929. Most of these compounds showed potential anticancer activity and low cytotoxicity on normal cell in vitro. 7d and 7f showed the best anticancer activity, whose IC₅₀ value is 15.43 μM and 20.54 μM towards MGC-803, respectively. Most of them exhibited topoisomerase II selective inhibitory. Cleavage reaction assay and DNA unwinding assay showed that 7f was a nonintercalative Topo II catalytic inhibitor, which was consistent with the docking results. Laser scanning confocal microscopy system tracks the location of representative compounds 7d and 7f which can be abundantly entering the nucleus. In particular, the most potent compounds 7d and 7f were shown to be able to induce G2/M cell cycle arrest and apoptosis in MGC-803 cells.

Recent advancements in the development of bioactive pyrazoline derivatives

Pyrazolines remain privileged heterocycles in drug discovery. 2-Pyrazoline scaffold has been proven as a ubiquitous motif which is present in a number of pharmacologically important drug molecules such as antipyrine, ramifenazone, ibipinabant, axitinib etc. They have been widely explored by the scientific community and are reported to possess wide spectrum of biological activities. For combating unprecedented diseases and worldwide increasing drug resistance, 2-pyrazoline has been tackled as a fascinating pharmacophore to generate new molecules with improved potency and lesser toxicity along with desired pharmacokinetic profile. This review aims to summarizes various recent advancements in the medicinal chemistry of pyrazoline based compounds with the following objectives: (1) To represent inclusive data on pyrazoline based marketed drugs as well as therapeutic candidates undergoing preclinical and clinical developments; (2) To discuss recent advances in the medicinal chemistry of pyrazoline derivatives with their numerous biological significances for the eradication of various diseases; (3) Summarizes structure-activity relationships (SAR) including in silico and mechanistic studies to afford ideas for the design and development of novel compounds with desired therapeutic implications.

Design and efficient synthesis of pyrazoline and isoxazole bridged indole C-glycoside hybrids as potential anticancer agents

C-glycosides are important class of molecules exhibit diverse biological activities and present as structural motif in many natural products. Two series of new pyrazoline and isoxazole bridged indole C-glycoside molecular hybrids (n = 36) were efficiently synthesized starting from diverse indole 3-carboxaldehydes derived α, β-unsaturated ketone derivatives of β-D-glucosyl-propan-2-one, β-D-galactosyl-propan-2-one and β-D-mannosyl-propan-2-one, reacting with hydrazine hydrate and hydroxyl amine hydrochloride in shorter reaction time (15 min) under microwave assisted condition. Anticancer activity of these newly synthesized pyrazoline and isoxazole bridged indoles C-glycoside hybrids were determined in details through cellular assays against MCF-7, MDA-MB-453 and MDA-MB-231 cancer cell lines. The selected library members displayed low micromolar (IC₅₀ = 0.67–4.67 µM) and selective toxicity against breast cancer cell line (MCF-7). Whereas these compounds were nontoxic towards normal cell line (MCF-10A). Mechanistic studies showed that, active compounds inhibit COX-2 enzyme, which was also supported by molecular docking studies. These findings are expected to provide new leads towards anticancer drug discovery.

Two groups of copperII pyridine–triazole complexes with “open or close” pepper rings and their in vitro antitumor activities

Based on 1,2-dimethoxyphenyl (veratrole, open) and 1,2-methylenedioxyphenyl (pepper ring, close)-derived pyridine–triazole analogues, two groups of copper(ii) complexes, namely, Group I(C1–C3) and Group II(C4–C6) were synthesized and fully characterized. All ligands and complexes were tested in vitro by MTT assays on seven tumour cell lines (T24, Hep-G2, Sk-Ov-3, MGC-803, HeLa, A549 and NCI-H460) and one normal liver cell line (HL-7702). Surprisingly, the pepper-ring-derived complexes (C4–C6) showed significantly enhanced cytotoxicity compared with the 1,2-bimethoxyphenyl ring-derived complexes (C1–C3) and the standard anticancer drug cisplatin. Cellular uptake assays indicated that the Cu accumulation was consistent with cytotoxicity. In addition, flow cytometry and western blot analysis showed that the apoptosis of the leading complex C4 may be induced by the Bcl-2 family-mediated proteins through the mitochondrial dysfunction pathway. Furthermore, UV-vis and fluorescence spectroscopy assays revealed that C4 has stronger insertion-binding interactions with CT-DNA than C1 and the fluorescence of C1 and C4 with BSA is mainly quenched by static quenching.

The pepper ring-modified complexes (Group II, C4–C6) exhibited significant antitumor activity than veratrole-modified complexes (Group I, C1–C3) towards several cancer cells with IC₅₀ ranging from 3.45 to 8.59 μM.

Design, synthesis and biological evaluation of novel α-aminophosphonate oxadiazoles via optimized iron triflate catalyzed reaction as apoptotic inducers

α-aminophosphonate oxadiazoles (5a-m) were prepared in high yields by reacting of 1,3,4-oxadiazole acetohydrazide (3) with appropriate aldehydes and diethyl phosphite under Kabachnik-Fields conditions using Iron triflate as a catalyst. The reaction conditions were optimized using D-optimal experimental design. Possible reaction mechanisms were considered, and structures of the new products were based upon compatible elementary and spectroscopic evidence. In vitro antitumor activities of these compounds were evaluated against human cancer cell lines of colon (HCT116), breast (MCF7) and liver (HepG2) and compared with anticancer drug, Doxorubicin, employing standard MTT assay. Compounds 5i and 5l demonstrated good antiproliferative activities against HCT116 tumor cells comparable to doxorubicin with low cytotoxicity towards normal fetal colon cell (FHC). Additionally, their capacity to activate apoptosis cascade was studied in HCT116 cell line by investigating the activation of proteolytic caspases cascade, the levels of Cytochrome C, Bax and Bcl-2. Active caspase-3 level was enhanced by 6-8-folds in HCT116 cell line when stimulated with compounds 5i and 5l compared to the control. The level of Caspases 8 & 9 was also increased signifying that intrinsic and extrinsic pathways are both activated. They also induced Bax and down regulated Bcl-2 protein level in addition to over-expressing Cytochrome C level in HCT116 cell line. Also, HCT116 cell cycle was mainly arrested at the Pre-G1 and G2/M phases when treated with compounds 5i and 5l.

Synthesis and biological evaluation of 3-amino-, 3-alkoxy- and 3-aryloxy-6-(hetero)arylpyridazines as potent antitumor agents

Various 3-amino-, 3-aryloxy- and alkoxy-6-arylpyridazines have been synthesized by an electrochemical reductive cross-coupling between 3-amino-, 3-aryloxy- or 3-alkoxy-6-chloropyridazines and aryl or heteroaryl halides. In vitro antiproliferative activity of these products was evaluated against a representative panel of cancer cell lines (HuH7, CaCo-2, MDA-MB-231, HCT116, PC3, NCI-H727, HaCaT) and oncogenicity prevention of the more efficient derivatives was highlighted on human breast cancer cell line MDA-MB 468-Luc prior establishing their interaction with p44/42 and Akt-dependent signaling pathways.

One-pot synthesis, biological evaluation and molecular docking studies of fused thiazolo[2,3-b]pyrimidinone-pyrazolylcoumarin hybrids

As a part of our endeavor toward the synthesis of a new class of biologically potent heterocyclic hybrids, a series of newly fused thiazolo[2,3-b]pyrimidinones bearing a pyrazolylcoumarin moiety (6a-p) were synthesized in acceptable yields. Anticipated structures of all titled compounds were in agreement with spectral and analytical (C, H and N) analyses. The compounds were screened for in vitro antibacterial activity against both G⁺ and G^- bacterial strains and antiproliferative activity against K562 (chronic myelogenous leukemia), MCF-7 (breast cancer), MDA-MB-231 (breast cancer), COLO 205 (colorectal adenocarcinoma), HepG2 (hepatocellular carcinoma) cell lines. Further, potent antibacterial compounds were subjected to molecular docking studies in order to gain insight into their plausible binding modes and mechanism of action against MurB. The modeling results were in agreement with the experimental data.

Facile synthesis of some pyrazoline-based compounds with promising anti-inflammatory activity

Aim: Search for new anti-inflammatory agents with higher efficacy and lower toxicity is an urgent demand in drug discovery era. Methodology: Different pyrazoline derivatives 4a,b, 5a,b, 6a–h and 7a–f were prepared from the condensation reactions of 1,5-bis(5-methylfuran/thiophen-2-yl)penta-1,4-dien-3-ones 3a,b with different hydrazine derivatives. All compounds were screened for their anti-inflammatory activity using the carrageenan-induced paw edema method in rats and TNF-α inhibition assay. Results: Many compounds revealed promising anti-inflammatory activity relative to indomethacin especially compounds 4a, 5a, 5b, 6b, 6d, 6f and 7b. They were safe to the gastric mucosa and did not cause toxicity up to tenfolds the anti-inflammatory dose, in addition, all compounds inhibited TNF-α with IC50 values of 1.7–100 nM.

Antitumor potential of 1-thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H-pyrazoles in human bladder cancer cells

Bladder cancer is a genitourinary malignant disease common worldwide. Current chemotherapy is often limited mainly due to toxicity and drug resistance. Thus, there is a continued need to discover new therapies. Recently evidences shows that pyrazoline derivatives are promising antitumor agents in many types of cancers, but there are no studies with bladder cancer. In order to find potent and novel chemotherapy drugs for bladder cancer, a series of pyrazoline derivatives 2a-2d were tested for their antitumor activity in two human bladder cancer cell lines 5647 and T24. The MTT assay showed that the compounds 1-thiocarbamoyl-3,5-diphenyl-4,5-dihydro-1H-pyrazole (2a) and 1-thiocarbamoyl-5-(4-chlorophenyl)-3-phenyl-4,5-dihydro-1H-pyrazole (2c) decrease the cell viability of 5637 cells. Molecular modeling indicated that these compounds had a good oral bioavailability and low toxicities. Clonogenic assay and flow cytometric analysis were used to assess colony formation, apoptosis induction and cell cycle distribution. Overall, our results suggest that pyrazoline 2a and 2c, with the substituents hydrogen and chlorine respectively, may decrease cell viability and colony formation of bladder cancer 5637 cell line by inhibition of cell cycle progression, and for pyrazoline 2a, by induction of apoptosis. As indicated by the physicochemical properties of these compounds, the steric factor influences the activity. Therefore, these pyrazoline derivatives can be considered promising anticancer agents for the treatment of bladder cancer.

Unveiling a versatile heterocycle: pyrazoline – a review

The design and synthesis of novel fluorescent heterocyclic dyes is a “hotspot” research area, due to their favourable photophysical and electronic properties, which could allow huge advances in the fields of physics, chemistry and biology.

Design, synthesis, and in vivo evaluations of benzyl Nω-nitro-Nα-(9H-pyrido[3,4-b]indole-3-carbonyl)-l-argininate as an apoptosis inducer capable of decreasing the serum concentration of P-selectin

A series of findings suggest that the discovery of in vivo apoptosis inducers for chemotherapy is of clinical importance.

Synthesis of functionalized tetrahydropyridazines via catalyst-free self [4 + 2] cycloaddition of in situ generated 1,2-diaza-1,3-dienes

An efficient method for the synthesis of structurally diverse functionalized tetrahydropyridazines via self [4 + 2] cycloaddition of in situ generated 1,2-diaza-1,3-dienes was developed, which may play an important role in drug discovery.