Novel pyridine and pyrimidine derivatives as promising anticancer agents: A review

Poly (ADP-ribose) polymerase (PARP) inhibitors as anticancer agents: An outlook on clinical progress, synthetic strategies, biological activity, and structure-activity relationship

Poly (ADP-ribose) polymerase (PARP) is considered an essential component in case of DNA (Deoxyribonucleic acid) damage, response by sensing DNA damage and engaging DNA repair proteins. Those proteins repair the damaged DNA via an aspect of posttranslational modification, known as poly (ADP-Ribosyl)ation (PARylation). Specifically, PARP inhibitors (PARPi) have shown better results when administered alone in a variety of cancer types with BRCA (Breast Cancer gene) mutation. The clinical therapeutic benefits of PARP inhibitors have been diminished by their cytotoxicity, progression of drug resistance, and limitation of indication, regardless of their tremendous clinical effectiveness. A growing number of PARP-1 inhibitors, particularly those associated with BRCA-1/2 mutations, have been identified as potential cancer treatments. Recently, several researchers have identified various promising scaffolds, which have resulted in the resuscitation of the faith in PARP inhibitors as cancer therapies. This review provided a comprehensive update on the anatomy and physiology of the PARP enzyme, the profile of FDA (Food and Drug Administration) and CFDA (China Food and Drug Administration)-approved drugs, and small-molecule inhibitors of PARP, including their synthetic routes, biological evaluation, selectivity, and structure-activity relationship.

Palladium and platinum complexes based on pyridine bases induced anticancer effectiveness via apoptosis protein signaling in cancer cells

Palladium and platinum complexes, especially those that include cisplatin, can be useful chemotherapeutic drugs. Alternatives that have less adverse effects and require lower dosages of treatment could be provided by complexes containing pyridine bases. The complexes [Pd(SCN)2(4-Acpy)2] (1), [Pd(N3)2(4-Acpy)2] (2) [Pd(paOH)2].2Cl (3) and [Pt(SCN)2(paO)2] (4) were prepared by self-assembly method at ambient temperature; (4-Acpy = 4-acetylpyridine and paOH = pyridine-2-carbaldehyde-oxime). The structure of complexes 1-4 was confirmed using spectroscopic and X-ray crystallography methods. Complexes 1-4 have similar features in isomerism that include the trans coordination geometry of pyridine ligands with Pd or Pt ion. The 3D network structure of complexes 1-4 was constructed by an infinite number of discrete mononuclear molecules extending via H-bonds. The Pd and Pt complexes 1-4 with pyridine ligands were assessed on MCF-7, T47D breast cancer cells and HCT116 colon cancer cells. The study evaluated cell death through apoptosis and cell cycle phases in MCF-7 cells treated with palladium or platinum conjugated with pyridine base. Upon treatment of MCF-7 with these complexes, the expression of apoptotic signals (Bcl2, p53, Bax and c-Myc) and cell cycle signals (p16, CDK1A, CDK1B) were evaluated. Compared to other complexes and cisplatin, IC50 of complex 1 was lowest in MCF-7 cells and complex 2 in T47D cells. Complex 4 has the highest effectiveness on HCT116. The selective index (SI) of complexes 1-4 has a value of more than two for all cancer cell lines, indicating that the complexes were less toxic to normal cells when given the same dose. MCF-7 cells treated with complex 2 and platinum complex 4 exhibited the highest level of early apoptosis. p16 may be signal arrest cells in Sub G, which was observed in cells treated with palladium complexes that suppress excessive cell proliferation. High c-Myc expression of treated cells with four complexes 1-4 and cisplatin could induce p53. All complexes 1-4 elevated the expression of Bax and triggered by the tumor suppressor gene p53. p53 was downregulating the expression of Bcl2.

Expedient, regioselective C-H chalcogenation of 3,4-dihydro-1,4-benzoxazines using a palladium-copper catalyst

The palladium-catalysed regioselective C-H chalcogenation of benzoxazines with disulfides and diselenides in air has been described. In this protocol, palladium acetate serves as the catalyst in conjunction with copper as an oxidizing agent. Through this approach, a wide array of sulfenylation and selenylation reactions of benzomorpholines have been effected, yielding results ranging from good to excellent. Thus, the established procedure demonstrates superb regioselectivity and a strong tolerance towards various functional groups and is suitable for gram-scale synthesis. Additionally, this synthetic approach offers a practical and convenient pathway for late-stage functionalization leading to the Rosenmund-von Braun reaction.

A survey of isatin hybrids and their biological properties

The emergence of diverse infections worldwide, which is a serious global threat to human existence, necessitates the urgent development of novel therapeutic candidates that can combat these diseases with efficacy. Molecular hybridization has been established as an efficient technique in designing bioactive molecules capable of fighting infections. Isatin, a core nucleus of an array of compounds with diverse biological properties can be modified at different positions leading to the creation of novel drug targets, is an active area of medicinal chemistry. This review containing published articles from 2005 to 2022 highlights isatin hybrids which have been synthesized and reported in the literature alongside a discussion on their biological properties. The enriched structure-activity relationship studies discussed provides insights for the rational design of novel isatin hybrids with tailored biological properties as effective therapeutic candidates inspired by nature.

Coumarin as an Elite Scaffold in Anti-Breast Cancer Drug Development: Design Strategies, Mechanistic Insights, and Structure-Activity Relationships

Breast cancer is the most common cancer among women. Currently, it poses a significant threat to the healthcare system due to the emerging resistance and toxicity of available drug candidates in clinical practice, thus generating an urgent need for the development of new potent and safer anti-breast cancer drug candidates. Coumarin (chromone-2-one) is an elite ring system widely distributed among natural products and possesses a broad range of pharmacological properties. The unique distribution and pharmacological efficacy of coumarins attract natural product hunters, resulting in the identification of numerous natural coumarins from different natural sources in the last three decades, especially those with anti-breast cancer properties. Inspired by this, numerous synthetic derivatives based on coumarins have been developed by medicinal chemists all around the globe, showing promising anti-breast cancer efficacy. This review is primarily focused on the development of coumarin-inspired anti-breast cancer agents in the last three decades, especially highlighting design strategies, mechanistic insights, and their structure-activity relationship. Natural coumarins having anti-breast cancer efficacy are also briefly highlighted. This review will act as a guideline for researchers and medicinal chemists in designing optimum coumarin-based potent and safer anti-breast cancer agents.

Synthesis and antitumor activities of novel 3-(6-aminopyridin-3-yl)benzamide derivatives: Inducing cell cycle arrest and apoptosis via AURKB transcription inhibition

Here, a series of 3-(6-aminopyridin-3-yl) benzamide derivatives were designed and synthesized. Cell viability assay indicated that most compounds exhibited potent antiproliferative activity against all the tested cancer cells. Among them, compound 7l displayed the best antiproliferative activity particularly in A549 cells, with an IC50 value of 0.04 ± 0.01 μM. RNA-seq analysis was employed to explore the potential pathways related to the antiproliferative activity of compound 7l. The data revealed that 7l exerted antiproliferative activity mainly by regulating cell cycle, DNA replication and p53 signaling pathway. Indeed, compound 7l induced G2/M phase arrest by AURKB transcription inhibition and resulted in cell apoptosis via p53 signaling pathway. Most importantly, compound 7l demonstrated potent antitumor activity in A549 xenograft tumor model. Collectively, 7l might be a promising lead compound for the development of new therapeutic agents for AURKB overexpressed or mutated cancers.

Metal-Free Visible-Light Catalytic Deoxygenation of Azaaryl N-Oxides: Harnessing Photons for Efficient Greener Synthesis

Regio- and chemo-selective functionalization of electron deficient azaarenes often required their transformations to corresponding N-oxides and subsequent removal of oxygen after functionalization to get back the desired substituted azaarenes. An efficient metal-free visible-light photo-redox catalytic deoxygenation of N-oxides of azaheterocyclic compounds has been developed using acridinium based organo-photocatalyst in blue LED light. High efficiency and mildness of this methodology has been demonstrated through higher deoxygenation yield of wide variety of azaheterocyclic N-oxides with reactive functional groups. Robustness of the photocatalytic reduction has been demonstrated through easy scaling-up of the reaction to gram level without much change in the reaction yield.

An insight into thymidylate synthase inhibitor as anticancer agents: an explicative review

Cancer, a widespread challenge to global health, remains a puzzle of intricate molecular dynamics. This review article delves into the mystery of cancer, with a keen focus on understanding the contributory role of thymidylate synthase (TS) in cancer. TS, a vital enzyme in DNA synthesis and repair, emerges as a significant player in the narrative of cancer development. The conversion of deoxyuridine monophosphate (dUMP) to deoxythymidine monophosphate (dTMP) is a major step in producing DNA. Numerous malignancies, including those of the breast, colon, lung, and ovary, have been linked to dysregulation of TS activity. Overexpression or mutations of TS lead to uncontrolled cell proliferation and tumorigenesis molecular interactions and signalling pathways involving TS come under scrutiny, revealing the nuanced connections that propel its involvement in cancer progression. Beyond overexpression and mutations, there emerges a subtle layer of regulation that involves microRNAs (miRNAs). These tiny particles attach to the TS messenger RNA, causing translational repression or its degradation, which in turn affects TS activity. Moving towards the therapeutic realm, thymidylate synthase inhibition acts as a promising anti-cancer strategy. Targeting TS with small-molecule inhibitors could provide a novel approach to treat various cancers. By reducing the number of available nucleotides, TS inhibition would slow down or halt cancer cell division, thus depriving the tumor of the building blocks required for its proliferation and growth. The aim is to assess the viability and effectiveness of targeting TS to halt or slow down cancer progression. There is growing evidence that, in comparison to traditional TS inhibitors, few novel antifolate TS inhibitors are effective against a wider variety of neoplasms, such as lung carcinomas. It has been discovered that TS inhibitors increase cancer tissues' sensitivity to chemotherapy and radiation, increasing their vulnerability to these treatments. This article aims to provide a comprehensive insight into TS, examining its cellular details, detailing the heterocyclic moieties and molecular foundations, and providing a promising future outlook.

Recent developments of hydroxamic acid hybrids as potential anti-breast cancer agents

Histone deacetylase inhibitors not only possess favorable effects on modulating tumor microenvironment and host immune cells but also can reactivate the genes silenced due to deacetylation and chromatin condensation. Hydroxamic acid hybrids as promising histone deacetylase inhibitors have the potential to address drug resistance and reduce severe side effects associated with a single drug molecule due to their capacity to simultaneously modulate multiple targets in cancer cells. Accordingly, rational design of hydroxamic acid hybrids may provide valuable therapeutic interventions for the treatment of breast cancer. This review aimed to provide insights into the in vitro and in vivo anti-breast cancer therapeutic potential of hydroxamic acid hybrids, together with their mechanisms of action and structure-activity relationships, covering articles published from 2020 to the present.

Target identification, and optimization of dioxygenated amide derivatives as potent antibacterial agents with FabH inhibitory activity

The enzyme FabH plays a critical role in the initial step of fatty acid biosynthesis, which is vital for the survival of bacteria. As a result, FabH has emerged as an appealing target for the development of novel antibacterial agents. In this study, employing the chemical proteomics method, we validated the previously identified skeleton amide derivatives bearing dioxygenated rings, potentially formed through metabolic processes. Building upon the proteomics findings, we then synthesized and evaluated 32 compounds containing N-heterocyclic amides for their antimicrobial activity for future optimizing the deoxygenated amides. Several compounds demonstrated potent antimicrobial properties with low toxicity, particularly compound 25, which exhibited remarkable potential as an agent with an MIC range of 1.25-3.13 μg/mL against the tested bacterial strains and an IC50 of 2.0 μM against E. coli-derived FabH. Furthermore, we evaluated nine analogues with relatively low MIC values through cytotoxicity and hemolytic activity assessments, Lipinski's rule-of-five criteria, and in silico ADMET predictions to ascertain their druggability potential. Notably, a detailed docking simulation was performed to investigate the binding interactions of compound 25 within the binding pocket of E. coli FabH, which encouragingly revealed strong binding interactions. Based on our findings, compound 25 emerges as the optimal candidate for in vivo therapy aimed at treating infected skin defects. Remarkably, the application of compound 25 demonstrated a significant reduction in the duration of wound infection and notably accelerated the healing process of infected wounds, achieving an impressive 94 % healing rate by day 10.

Recent drug design strategies and identification of key heterocyclic scaffolds for promising anticancer targets

Cancer, a noncommunicable disease, is the leading cause of mortality worldwide and is anticipated to rise by 75% in the next two decades, reaching approximately 25 million cases. Traditional cancer treatments, such as radiotherapy and surgery, have shown limited success in reducing cancer incidence. As a result, the focus of cancer chemotherapy has switched to the development of novel small molecule antitumor agents as an alternate strategy for combating and managing cancer rates. Heterocyclic compounds are such agents that bind to specific residues in target proteins, inhibiting their function and potentially providing cancer treatment. This review focuses on privileged heterocyclic pharmacophores with potent activity against carbonic anhydrases and kinases, which are important anticancer targets. Evaluation of ongoing pre-clinical and clinical research of heterocyclic compounds with potential therapeutic value against a variety of malignancies as well as the provision of a concise summary of the role of heterocyclic scaffolds in various chemotherapy protocols have also been discussed. The main objective of the article is to highlight key heterocyclic scaffolds involved in recent anticancer drug design that demands further attention from the drug development community to find more effective and safer targeted small-molecule anticancer agents.

De Novo Green Fluorescent Protein Chromophore-Based Probes for Capturing Latent Fingerprints Using a Portable System

Rapid visualization of latent fingerprints, preferably at their point of origin, is essential for effective crime scene evaluation. Here, we present a new class of green fluorescent protein chromophore-based fluorescent dyes (LFP-Yellow and LFP-Red) that can be used for real-time visualization of LFPs within 10 s. Compared with traditional chemical reagents for LFPs, these fluorescent dyes are completely water-soluble, exhibit low cytotoxicity, and are harmless to users. Level 1-3 details of the LFPs could be clearly revealed through "off-on" fluorescence signal readout. Additionally, the fluorescent dyes were constructed based on an imidazolinone core and so do not contain pyridine groups or metal ions, which ensures that the DNA is not contaminated during extraction and identification after the LFPs are treated with the dyes. Combined with our as-developed portable system for capturing LFPs, LFP-Yellow and LFP-Red enabled the rapid capture of LFPs. Therefore, these green fluorescent protein chromophore-based probes provide an approach for the rapid identification of individuals who were present at a crime scene.

Synthesis, design, biological evaluation, and computational analysis of some novel uracil-azole derivatives as cytotoxic agents

The design and synthesis of novel cytotoxic agents is still an interesting topic for medicinal chemistry researchers due to the unwanted side effects of anticancer drugs. In this study, a novel series of uracil-azole hybrids were designed and synthesized. The cytotoxic activity, along with computational studies: molecular docking, molecular dynamic simulation, density functional theory, and ADME properties were also, evaluated. The compounds were synthesized by using 3-methyl-6-chlorouracil as the starting material. Cytotoxicity was determined using MTT assay in the breast carcinoma cell line (MCF-7) and Hepatocellular carcinoma cell line (HEPG-2). These derivatives demonstrated powerful inhibitory activity against breast and hepatocellular carcinoma cell lines in comparison to Cisplatin as positive control. Among these compounds, 4j displayed the best selectivity profile and good activity with IC50 values of 16.18 ± 1.02 and 7.56 ± 5.28 µM against MCF-7 and HEPG-2 cell lines respectively. Structure-activity relationships revealed that the variation in the cytotoxic potency of the synthesized compounds was affected by various substitutions of benzyl moiety. The docking output showed that 4j bind well in the active site of EGFR and formed a stable complex with the EGFR protein. DFT was used to investigate the reactivity descriptors of 4a and 4j. The outputs demonstrated that these uracil-azole hybrids can be considered as potential cytotoxic agents.

Nitrogen-fused Heterocycles: Empowering Anticancer Drug Discovery

The worldwide impact of cancer is further compounded by the constraints of current anticancer medications, which frequently exhibit a lack of selectivity, raise safety apprehensions, result in significant adverse reactions, and encounter resistance mechanisms. The current situation highlights the pressing need to develop novel and more precise anticancer agents that prioritize safety and target specificity. Remarkably, more than 85% of drugs with physiological activity contain heterocyclic structures or at least one heteroatom. Nitrogen-containing heterocycles hold a significant position among these compounds, emerging as the most prevalent framework within the realm of heterocyclic chemistry. This article explores the medicinal chemistry behind these molecules, highlighting their potential as game-changing possibilities for anticancer medication development. The analysis highlights the inherent structural variety in nitrogen-containing heterocycles, revealing their potential to be customized for creating personalized anticancer medications. It also emphasizes the importance of computational techniques and studies on the relationships between structure and activity, providing a road map for rational medication design and optimization. Nitrogen- containing heterocycles are a promising new area of study in the fight against cancer, and this review summarises the state of the field so far. By utilizing their inherent characteristics and exploiting cooperative scientific investigations, these heterocyclic substances exhibit potential at the forefront of pioneering therapeutic approaches in combating the multifaceted obstacles posed by cancer.

Applications of Pyrrole and Pyridine-based Heterocycles in Cancer Diagnosis and Treatment

BACKGROUND

The escalation of cancer worldwide is one of the major causes of economy burden and loss of human resources. According to the American Cancer Society, there will be 1,958,310 new cancer cases and 609,820 projected cancer deaths in 2023 in the United States. It is projected that by 2040, the burden of global cancer is expected to rise to 29.5 million per year, causing a death toll of 16.4 million. The hemostasis regulation by cellular protein synthesis and their targeted degradation is required for normal cell growth. The imbalance in hemostasis causes unbridled growth in cells and results in cancer. The DNA of cells needs to be targeted by chemotherapeutic agents for cancer treatment, but at the same time, their efficacy and toxicity also need to be considered for successful treatment.

OBJECTIVE

The objective of this study is to review the published work on pyrrole and pyridine, which have been prominent in the diagnosis and possess anticancer activity, to obtain some novel lead molecules of improved cancer therapeutic.

METHODS

A literature search was carried out using different search engines, like Sci-finder, Elsevier, ScienceDirect, RSC etc., for small molecules based on pyrrole and pyridine helpful in diagnosis and inducing apoptosis in cancer cells. The research findings on the application of these compounds from 2018-2023 were reviewed on a variety of cell lines, such as breast cancer, liver cancer, epithelial cancer, etc. Results: In this review, the published small molecules, pyrrole and pyridine and their derivatives, which have roles in the diagnosis and treatment of cancers, were discussed to provide some insight into the structural features responsible for diagnosis and treatment. The analogues with the chromeno-furo-pyridine skeleton showed the highest anticancer activity against breast cancer. The compound 5-amino-N-(1-(pyridin-4- yl)ethylidene)-1H-pyrazole-4-carbohydrazides was highly potent against HEPG2 cancer cell. Redaporfin is used for the treatment of cholangiocarcinoma, biliary tract cancer, cisplatin-resistant head and neck squamous cell carcinoma, and pigmentation melanoma, and it is in clinical trials for phase II. These structural features present a high potential for designing novel anticancer agents for diagnosis and drug development.

CONCLUSION

Therefore, the N- and C-substituted pyrrole and pyridine-based novel privileged small Nheterocyclic scaffolds are potential molecules used in the diagnosis and treatment of cancer. This review discusses the reports on the synthesis of such molecules during 2018-2023. The review mainly discusses various diagnostic techniques for cancer, which employ pyrrole and pyridine heterocyclic scaffolds. Furthermore, the anticancer activity of N- and C-substituted pyrrole and pyridine-based scaffolds has been described, which works against different cancer cell lines, such as MCF-7, A549, A2780, HepG2, MDA-MB-231, K562, HT- 29, Caco-2 cells, Hela, Huh-7, WSU-DLCL2, HCT-116, HBL-100, H23, HCC827, SKOV3, etc. This review will help the researchers to obtain a critical insight into the structural aspects of pyrrole and pyridine-based scaffolds useful in cancer diagnosis as well as treatment and design pathways to develop novel drugs in the future.

Evaluation of anticancer potential of tetracene-5,12-dione (A01) and pyrimidine-2,4-dione (A02) via caspase 3 and lactate dehydrogenase cytotoxicity investigations

Cancer stands as a significant global cause of mortality, predominantly arising from the dysregulation of key enzymes and DNA. One strategic avenue in developing new anticancer agents involves targeting specific proteins within the cancer pathway. Amidst ongoing efforts to enhance the efficacy of anticancer drugs, a range of crucial medications currently interact with DNA at the molecular level, exerting profound biological effects. Our study is driven by the objective to comprehensively explore the potential of two compounds: (7S,9S)-7-[(2R,4S,5S,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-6,9,11-trihydroxy-9-(2-hydroxyacetyl)-4-methoxy-8,10-dihydro-7H-tetracene-5,12-dione (A01) and 5-fluoro-1H-pyrimidine-2,4-dione (A02). These compounds have demonstrated marked efficacy against breast and cervical cancer cell lines, positioning them as promising anticancer candidates. In our investigation, A01 has emerged as a particularly potent candidate, with its potential bolstered by corroborative evidence from lactate dehydrogenase release and caspase-3 activity assays. On the other hand, A02 has exhibited remarkable anticancer potential. To further elucidate their molecular mechanisms and interactions, we employed computational techniques, including molecular docking and molecular dynamics simulations. Notably, our computational analyses suggest that the A01-DNA complex predominantly interacts via the minor groove, imparting significant insights into its mechanism of action. While earlier studies have also highlighted the anticancer activity of A01, our research contributes by providing a deeper understanding of its binding mechanisms through computational investigations. This knowledge holds potential for designing more effective drugs that target cancer-associated proteins. These findings lay a robust groundwork for future inquiries and propose that derivatives of A01 could be synthesized as potent bioactive agents for cancer treatment. By elucidating the distinctive aspects of our study's outcomes, we address the concern of distinguishing our findings from those of prior research.

Hydroxamic acid hybrids: Histone deacetylase inhibitors with anticancer therapeutic potency

Histone deacetylases (HDACs), a class of enzymes responsible for the removal of acetyl functional groups from the lysine residues in the amino-terminal tails of core histones, play a critical role in the modulation of chromatin architecture and the regulation of gene expression. Dysregulation of HDAC expression has been closely associated with the development of various cancers. Histone deacetylase inhibitors (HDACis) could regulate diverse cellular pathways, cause cell cycle arrest, and promote programmed cell death, making them promising avenues for cancer therapy with potent efficacy and favorable toxicity profiles. Hybrid molecules incorporating two or more pharmacophores in one single molecule, have the potential to simultaneously inhibit two distinct cancer targets, potentially overcome drug resistance and minimize drug-drug interactions. Notably, hydroxamic acid hybrids, exemplified by fimepinostat and tinostamustine as potential HDACis, could exert the anticancer effects through induction of apoptosis, differentiation, and growth arrest in cancer cells, representing useful scaffolds for the discovery of novel HDACis. The purpose of this review is to summarize the current scenario of hydroxamic acid hybrids as HDACis with anticancer therapeutic potential developed since 2020 to facilitate further rational exploitation of more effective candidates.

Efficient Protocol for Novel Hybrid Pyrimidines Synthesis: Antiproliferative Activity, DFT Analyses, and Molecular Docking Studies

An efficient, microwave/ultrasound-irradiated synthesis of novel chromenopyrimidines has been established. 2-Amino-5-oxo-4-(thiophen-2-yl)-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (1) underwent cyclization reactions with various assorted reagents under sustainable conditions to afford a family of fused pyrimidine derivatives. The proposed structures of the designed fused pyrimidines were confirmed by several spectral techniques. Moreover, the targeted pyrimidines were estimated for their in vitro cytotoxic activities toward three carcinoma cell lines: breast (MCF7), hepatocyte (HepG2), and lung (A549) cancer cell lines, as well as one noncancerous cell line (MCF-10A). Structure-activity relationship (SAR) analyses revealed that derivatives 3 and 7 exhibited the highest potency in inhibiting the growth of cancer cells tested in vitro. Particularly, 3-amino-4-imino-5-(thiophen-2-yl)-3,4,5,7,8,9-hexahydro-6H-chromeno[2,3-d]pyrimidin-6-one (3) displayed a robust impact with IC50 values ranging from 2.02 to 1.61 μM. Interestingly, compound 3 was observed to have low cytotoxicity toward noncancerous cell (MCF-10A) compared to the standard drug (Doxorubicin). Further, quantum chemical computations of the designed molecules utilizing density functional theory (DFT) were conducted and shown to be compatible with the observed antiproliferative properties. Thorough docking investigations revealed that the assembled compounds possess exceptionally low binding energies toward our three selected proteins: 4b3z-Lung, HepG2-2JW2, and 6ENV-MCV-7. Based on these intriguing results, compound 3 could be further evaluated for preclinical screening, potentially paving the way for its utilization as a promising cancer treatment.

Synthesis, molecular modeling Insights, and anticancer assessment of novel polyfunctionalized Pyridine congeners

The present study describes synthesizing a novel series of polyfunctionalized pyridine congeners 1-18 and assessed for cytotoxic efficacies versus HCT-116, MCF-7, and HepG-2 among one non-cancerous BJ-1 human normal cell. Most compounds were precisely potent anticancer candidate drugs. The molecular impact of the most active compounds 9, 10, 11, 13, 15, and 17 was evaluated after MCF-7 treatment. The gene expression of pro- and ant-apoptosis markers P53, Bax, Caspase-3 and Bcl-2 as well as VEGFR-2 and HER2 were determined. Compounds 13 and 15 induced upregulation of pro-apoptosis of P53, Bax, Caspase-3 and downregulation of anti-apoptosis Bcl-2 gene. However, compound 15 showed higher effect compared to 13 and respective control. Moreover, a slight reduction in HER2 gene expression was detected due to compound 15 treatment, while VEGFR-2 gene was upregulated. In agreement, the immunoblotting analysis showed higher accumulation of P53, Bax, Caspase-3 proteins and of decrease the Bcl-2 protein levels. Furthermore, docking studies united with molecular dynamic simulation exposed compounds 13 and 15 fitting in the middle of the active site at the interface linking the ATP binding site and the allosteric hydrophobic binding pocket. Finally, we performed Petra/Osiris/ Molinspiration (POM) analysis for the newly synthesized compounds. The evaluation of primary in silico parameters revealed significant differences among individual polyfunctionalized pyridine compounds, highlighting the most promising candidates. These preliminary results may help in coordinating and initiating other research projects focused on polyfunctionalized pyridine compounds, especially those with predicted bioactivity, low toxicity, optimal ADME parameters, and promising perspectives.

The anti-breast cancer potential of indole/isatin hybrids

Breast cancer (BC) is one of the most prevalent malignancies and the major contributor to cancer mortality in women globally, with a high degree of heterogeneity and a dismal prognosis. As drug resistance is responsible for most BC fatalities and advanced BC is currently considered incurable, finding innovative anti-BC chemotherapeutics is urgently required. Indole and its analog isatin (indole-1H-2,3-dione) are prominent pharmacophores in the development of novel medications, and their derivatives exhibit strong anticancer activities, also against BC. In particular, indole/isatin hybrids exhibit significant potency against BC including multidrug-resistant forms and excellent selectivity by influencing a variety of biological targets associated with the disease, supplying helpful building blocks for the identification of potential new BC treatment options. This review includes articles from 2020 to the present and provides insights into the in vitro and in vivo anti-BC potential, molecular mechanisms, and structure-activity relationships (SARs) of indole/isatin hybrids that may be helpful in the development of innovative anti-BC chemotherapeutics.

Multicomponent Reaction Based Tolyl-substituted and Pyrene-Pyridine Conjugated Isomeric Ratiometric Fluorescent Probes: A Comparative Investigation of Photophysical and Hg(II)-Sensing Behaviors

Herein, the synthesis of pyrene conjugated 2,6-di-ortho-tolylpyridine and 2,6-di-para-tolylpyridine structural isomers were achieved efficiently through multicomponent Chichibabin pyridine synthesis reaction. The DFT, TD-DFT and experimental investigations were carried out to investigate the photophysical behaviors of the synthesized novel pyrene-pyridine based isomeric probes. Our studies revealed that, due to the continuous conjugation of the pyrene, pyridine and tolyl moieties, the dihedral angles of the trisubstituents on the central pyridine moiety significantly influences the photophysical properties of the synthesized novel pyrene based fluorescent probes. Further, we have comparatively investigated the sensing behaviors of the synthesized tolyl-substituted isomeric ratiometric fluorescent probes with metal ions, our studies reveals that both the ortho and para tolyl ratiometric fluorescent probes have distinct photoemissive properties in selectively sensing of Hg2+ ions. Our studies indicates that, the para-tolyl substituted isomer displays more red-shift in wavelength of emission band compared to its ortho isomer analogue during ratiometric fluorescent specific detection of Hg2+ ions.

Molecular properties prediction, anticancer and anti-inflammatory activities of some pyrimido[1,2-b]pyridazin-2-one derivatives

Introduction

The anticancer and anti-inflammatory activities of a novel series of eleven pyrimido[1,2-b]pyridazin-2-one analogues substituted at position 7 were assessed in the current study.

Methods

The physicochemical characteristics were studied using MolSoft software. The antiproliferative activity was investigated by MTT cell viability assay, and cell cycle analysis elucidated the antiproliferative mechanism of action. Western blot analysis examined the expression levels of key pro-apoptotic (Bax, p53) and pro-survival (Bcl-2) proteins. The anti-inflammatory activity was assessed by measuring the production levels of nitric oxide in RAW264.7 cells, and the expression levels of COX-2 enzyme in LPS-activated THP-1 cells. In addition, the gene expression of various pro-inflammatory cytokines (IL-6, IL-8, IL-1β, TNF-α) and chemokines (CCL2, CXCL1, CXCL2, CXCL3) was assessed by RT-qPCR.

Results

Compound 1 bearing a chlorine substituent displayed the highest cytotoxic activity against HCT-116 and MCF-7 cancer cells where IC50 values of 49.35 ± 2.685 and 69.32 ± 3.186 µM, respectively, were achieved. Compound 1 increased the expression of pro-apoptotic proteins p53 and Bax while reducing the expression of pro-survival protein Bcl-2. Cell cycle analysis revealed that compound 1 arrested cell cycle at the G0/G1 phase. Anti-inflammatory assessments revealed that compound 1 displayed the strongest inhibitory activity on NO production with IC50 of 29.94 ± 2.24 µM, and down-regulated the expression of COX-2. Compound 1 also induced a statistically significant decrease in the gene expression of various cytokines and chemokines.

Conclusion

These findings showed that the pyrimidine derivative 1 displayed potent anti-inflammatory and anticancer properties in vitro, and can be selected as a lead compound for further investigation.

Aminopyridone-linked benzimidazoles: a fragment-based drug design for the development of CDK9 inhibitors

Aim: A fragment-based design and synthesis of three novel series of aminopyridone-linked benzimidazoles as potential anticancer candidates with significant CDK9 inhibition was implemented. Materials & methods: All synthesized compounds were submitted to National Cancer Institute, 60 cell lines and seven-dose cytotoxicity toward three cancer cells. Results: Compounds 2, 4a, 4c, 4d, 6a and 8a exhibited significant cytotoxicity and selectivity with IC50 range of 7.61-57.75 μM. Regarding the mechanism either in vitro or in silico, 4a, 6a and 8a displayed potent CDK9 inhibition with IC50 value of 0.424-8.461 μM. Compound 6a arrested the cell cycle at S phase and induced apoptosis in MCF-7 cells. Conclusion: Compound 6a is a promising CDK9 inhibitor that warrants additional research for cancer treatment.

In Vitro Cytotoxicity and In Vivo Antitumor Activity of Lipid Nanocapsules Loaded with Novel Pyridine Derivatives

This study demonstrates high drug-loading of novel pyridine derivatives (S1-S4) in lipid- and polymer-based core-shell nanocapsules (LPNCs) for boosting the anticancer efficiency and alleviating toxicity of these novel pyridine derivatives. The nanocapsules were fabricated using a nanoprecipitation technique and characterized for particle size, surface morphology, and entrapment efficiency. The prepared nanocapsules exhibited a particle size ranging from 185.0 ± 17.4 to 223.0 ± 15.3 nm and a drug entrapment of >90%. The microscopic evaluation demonstrated spherical-shaped nanocapsules with distinct core-shell structures. The in vitro release study depicted a biphasic and sustained release pattern of test compounds from the nanocapsules. In addition, it was obvious from the cytotoxicity studies that the nanocapsules showed superior cytotoxicity against both MCF-7 and A549 cancer cell lines, as manifested by a significant decrease in the IC₅₀ value compared to free test compounds. The in vivo antitumor efficacy of the optimized nanocapsule formulation (S4-loaded LPNCs) was investigated in an Ehrlich ascites carcinoma (EAC) solid tumor-bearing mice model. Interestingly, the entrapment of the test compound (S4) within LPNCs remarkably triggered superior tumor growth inhibition when compared with either free S4 or the standard anticancer drug 5-fluorouracil. Such enhanced in vivo antitumor activity was accompanied by a remarkable increase in animal life span. Furthermore, the S4-loaded LPNC formulation was tolerated well by treated animals, as evidenced by the absence of any signs of acute toxicity or alterations in biochemical markers of liver and kidney functions. Collectively, our findings clearly underscore the therapeutic potential of S4-loaded LPNCs over free S4 in conquering EAC solid tumors, presumably via granting efficient delivery of adequate concentrations of the entrapped drug to the target site.

Optimization and Antibacterial Evaluation of Novel 3-(5-Fluoropyridine-3-yl)-2-oxazolidinone Derivatives Containing a Pyrimidine Substituted Piperazine

In this study, a series of novel 3-(5-fluoropyridine-3-yl)-2-oxazolidinone derivatives were designed and synthesized based on compounds previously reported, and their antibacterial activity was investigated. Then their antibacterial activity was investigated for the first time. Preliminary screening results showed that all these compounds exhibited antibacterial activity against gram-positive bacteria, including 7 drug-sensitive strains and 4 drug-resistant strains, among which compound 7j exhibited an 8-fold stronger inhibitory effect than linezolid, with a minimum inhibitory concentration (MIC) value of 0.25 µg/mL. Further molecular docking studies predicted the possible binding mode between active compound 7j and the target. Interestingly, these compounds could not only hamper the formation of biofilms, but also have better safety, as confirmed by cytotoxicity experiments. All these results indicate that these 3-(5-fluoropyridine-3-yl)-2-oxazolidinone derivatives have the potential to be developed into novel candidates for the treatment of gram-positive bacterial infections.

Recent Advances in Pyridine Scaffold: Focus on Chemistry, Synthesis, and Antibacterial Activities

Multidrug-resistant (MDR) pathogens have created a fatal problem for human health and antimicrobial treatment. Among the currently available antibiotics, many are inactive against MDR pathogens. In this context, heterocyclic compounds/drugs play a vital role. Thus, it is very much essential to explore new research to combat the issue. Of the available nitrogen-bearing heterocyclic compounds/drugs, pyridine derivatives are of special interest due to their solubility. Encouragingly, some of the newly synthesized pyridine compounds/drugs are found to inhibit multidrug-resistant S. aureus (MRSA). Pyridine scaffold bearing poor basicity generally improves water solubility in pharmaceutically potential molecules and has led to the discovery of numerous broad-spectrum therapeutic agents. Keeping these in mind, we have reviewed the chemistry, recent synthetic techniques, and bacterial preventative activity of pyridine derivatives since 2015. This will facilitate the development of pyridine-based novel antibiotic/drug design in the near future as a versatile scaffold with limited side effects for the next-generation therapeutics.

Current scenario of pyrazole hybrids with in vivo therapeutic potential against cancers

Chemotherapeutics occupy a pivotal role in the medication of different types of cancers, but the prevalence and mortality rates of cancer remain high. The drug resistance and low specificity of current available chemotherapeutics are the main barriers for the effective cancer chemotherapy, evoking an immediate need for the development of novel anticancer agents. Pyrazole is a highly versatile five-membered heterocycle with two adjacent nitrogen atoms and possesses remarkable therapeutic effects and robust pharmacological potency. The pyrazole derivatives especially pyrazole hybrids have demonstrated potent in vitro and in vivo efficacies against cancers through multiple mechanisms, inclusive of apoptosis induction, autophagy regulation, and cell cycle disruption. Moreover, several pyrazole hybrids such as crizotanib (pyrazole-pyridine hybrid), erdafitinib (pyrazole-quinoxaline hybrid) and ruxolitinib (pyrazole-pyrrolo [2,3-d]pyrimidine hybrid) have already been approved for the cancer therapy, revealing that pyrazole hybrids are useful scaffolds to develop novel anticancer agents. The purpose of this review is to summarize the current scenario of pyrazole hybrids with potential in vivo anticancer efficacy along with mechanisms of action, toxicity, and pharmacokinetics, covering papers published in recent 5 years (2018-present), to facilitate further rational exploitation of more effective candidates.

Green Synthesis of Novel Pyridines via One-Pot Multicomponent Reaction and Their Anti-Inflammatory Evaluation

A functional and environmentally green procedure for the design of novel pyridine 5a-h and 7a-d derivatives through two pathways is presented. The first pathway is via a one-pot, four-component reaction of p-formylphenyl-4-toluenesulfonate (1), ethyl cyanoacetate (2), acetophenone derivatives 3a-h or acetyl derivatives 6a-d, and ammonium acetate (4) under microwave irradiation in ethanol. The advantages of this method are an excellent yield (82%-94%), pure products, a short reaction time (2-7 min), and low-cost processing. The second pathway was obtained by the traditional method with treatment of the same mixture under refluxing in ethanol, which afforded the same products, 5a-h and 7a-d, in less yield (71%-88%) and over a longer reaction time (6-9 h). The constructions of the novel compounds were articulated via spectral and elemental analysis. Overall, the compounds have been designed, synthesized, and studied for their in vitro anti-inflammatory activity using diclofenac as a reference drug (5 mg/kg). The most potent four compounds, 5a, 5f, 5g, and 5h, showed promising anti-inflammatory activity.

Nitrogen Containing Heterocycles as Anticancer Agents: A Medicinal Chemistry Perspective

Cancer is one of the major healthcare challenges across the globe. Several anticancer drugs are available on the market but they either lack specificity or have poor safety, severe side effects, and suffer from resistance. So, there is a dire need to develop safer and target-specific anticancer drugs. More than 85% of all physiologically active pharmaceuticals are heterocycles or contain at least one heteroatom. Nitrogen heterocycles constituting the most common heterocyclic framework. In this study, we have compiled the FDA approved heterocyclic drugs with nitrogen atoms and their pharmacological properties. Moreover, we have reported nitrogen containing heterocycles, including pyrimidine, quinolone, carbazole, pyridine, imidazole, benzimidazole, triazole, β-lactam, indole, pyrazole, quinazoline, quinoxaline, isatin, pyrrolo-benzodiazepines, and pyrido[2,3-d]pyrimidines, which are used in the treatment of different types of cancer, concurrently covering the biochemical mechanisms of action and cellular targets.

Challenging breast cancer through novel sulfonamide-pyridine hybrids: design, synthesis, carbonic anhydrase IX inhibition and induction of apoptosis

Background: Among the important key modulators of the tumor microenvironment and hypoxia is a family of enzymes named carbonic anhydrases. Herein, 11 novel sulfonamide-pyridine hybrids (2-12) were designed, synthesized and biologically evaluated for their potential use in targeting breast cancer. Methods & results: The para chloro derivative 7 reported the highest cytotoxic activity against the three breast cancer cell lines used. In addition, compound 7 was found to induce cell cycle arrest and autophagy as well as delaying wound healing. The IC₅₀ of compound 7 against carbonic anhydrase IX was 253 ± 12 nM using dorzolamide HCl as control. Conclusion: This study encourages us to expand the designed library, where more sulfonamide derivatives would be synthesized and studied for their structure-activity relationships.

Evaluation of the anti-proliferative activity of 2-oxo-pyridine and 1′H-spiro-pyridine derivatives as a new class of EGFRWt and VEGFR-2 inhibitors with apoptotic inducers†

Developing new agents for cancer treatment remains a top priority because it is one of the deadliest worldwide. A new series of 2-oxo-pyridine and 1′H-spiro-pyridine derivatives were designed and synthesized based on an N-(ethyl benzoate) moiety. The structure of the designed derivatives was confirmed by different spectroscopic techniques (FT-IR and NMR) and elemental analysis and then evaluated as antiproliferative against HepG-2 and Caco-2 cell lines compared with Doxorubicin. The spiro-pyridine derivatives 5, 7, and 8 exhibited a remarkably higher activity against Caco-2 cell lines than that of other derivatives. Additionally, these derivatives exhibited activation in the Bax and suppressed Bcl-2 expression with variable degrees. Interestingly, compound 7 showed the lowest cytotoxicity value on Caco-2 cells (IC₅₀ = 7.83 ± 0.50 μM) compared with Doxorubicin (IC₅₀ = 12.49 ± 1.10 μM). Additionally, this compound showed activation of the Bax gene (7.508-fold) and suppressed Bcl-2 (0.194-fold) compared to untreated Caco-2 cells, as revealed by the qRT-PCR technique. Moreover, compound 7 could inhibit EGFR and VEGFR-2 with sub-micromole values of 0.124 μM and 0.221 μM compared with Erlotinib (IC₅₀ = 0.033 μM) and Sorafenib (IC₅₀ = 0.043 μM), respectively. Further, cell cycle and apoptosis analysis demonstrated that compound 7 promoted apoptosis by increasing the apoptosis rate from 1.92 to 42.35% and the S cell accumulation ratio from 31.18 to 42.07% compared to untreated Caco-2 cells. Finally, the most active compound 7 showed good drug-likeness and toxicity profiles. Besides, molecular docking studies were performed to determine the binding mode, which is in agreement with the in vitro results.

Design and synthesis a novel of 2-oxo-pyridine and 1′H-spiro-pyridine derivatives as a new apoptotic inducers agents.

Quantitative and Qualitative Analysis of the Anti-Proliferative Potential of the Pyrazole Scaffold in the Design of Anticancer Agents

The current work presents an objective overview of the impact of one important heterocyclic structure, the pyrazole ring, in the development of anti-proliferative drugs. A set of 1551 pyrazole derivatives were extracted from the National Cancer Institute (NCI) database, together with their growth inhibition effects (GI%) on the NCI’s panel of 60 cancer cell lines. The structures of these derivatives were analyzed based on the compounds’ averages of GI% values across NCI-60 cell lines and the averages of the values for the outlier cells. The distribution and the architecture of the Bemis–Murcko skeletons were analyzed, highlighting the impact of certain scaffold structures on the anti-proliferative effect’s potency and selectivity. The drug-likeness, chemical reactivity and promiscuity risks of the compounds were predicted using AMDETlab. The pyrazole ring proved to be a versatile scaffold for the design of anticancer drugs if properly substituted and if connected with other cyclic structures. The 1,3-diphenyl-pyrazole emerged as a useful scaffold for potent and targeted anticancer candidates.