Imidazopyridine-based kinase inhibitors as potential anticancer agents: A review.

Considering the fundamental role of protein kinases in the mechanism of protein phosphorylation in critical cellular processes, their dysregulation, especially in cancers, has underscored their therapeutic relevance. Imidazopyridines represent versatile scaffolds found in abundant bioactive compounds. Given their structural features, imidazopyridines have possessed pivotal potency to interact with different protein kinases, inspiring researchers to carry out numerous structural variations. In this comprehensive review, we encompass an extensive survey of the design and biological evaluations of imidazopyridine-based small molecules as potential agents targeting diverse kinases for anticancer applications. We describe the structural elements critical to inhibitory potency, elucidating their key structure-activity relationships (SAR) and mode of actions, where available. We classify these compounds into two groups: Serine/threonine and Tyrosine inhibitors. By highlighting the promising role of imidazopyridines in kinase inhibition, we aim to facilitate the design and development of more effective, targeted compounds for cancer treatment.

Imidazo[1,2-a]quinazolines as novel, potent EGFR-TK inhibitors: Design, synthesis, bioactivity evaluation, and in silico studies.

Tyrosine protein kinases (TKs) have been proved to play substantial roles on many cellular processes and their overexpression tend to be found in various types of cancers. Therefore, over recent decades, numerous tyrosine protein kinase inhibitors particularly epidermal growth factor receptor (EGFR) inhibitors have been introduced to treat cancer. Present study describes a novel series of imidazo[1,2-a]quinazolines 18 as potential -inhibitors. These imidazoquinazolines (18a and 18o, in particular) had great anti-proliferative activities with IC50 values in the micromolar (µM) range against PC3, HepG2, HeLa, and MDA-MB-231 comparing with Erlotinib as reference marketed drug. Further evaluations on some derivatives revealed their potential to induce apoptotic cell death and cell growth arrest at G0 phase of the cell cycle. Afterwards, the kinase assay on the most potent compounds 18a and 18o demonstrated their inhibitory potencies and selectivity toward EGFR (with EGFR-IC50 values of 82.0 µM and 12.3 µM, respectively). Additionally, western blot analysis on these compounds 18a and 18o exhibited that they inhibited the phosphorylation of EGFR and its downstream molecule extracellular signal-regulated kinase (ERK1/2). However, the level of B-Actin phosphorylation was not changed. Finally, density functional theory calculations, docking study, and independent gradient model (IGM) were performed to illustrate the structure-activity relationship (SAR) and to assess the interactions between proteins and ligands. The results of molecular docking studies had great agreement with the obtained EGFR inhibitory results through in vitro evaluations.

Novel fluoroquinolones analogues bearing 4-(arylcarbamoyl)benzyl: design, synthesis, and antibacterial evaluation.

Bacterial resistance to fluoroquinolone has been increasing at an alarming rate worldwide. In an attempt to find more potent anti-bacterial agents, an efficient, straightforward protocol was performed to obtain a large substrate scope of novel ciprofloxacin and sarafloxacin analogues conjugated with 4-(arylcarbamoyl)benzyl 7a-ab. All prepared compounds were evaluated for their anti-bacterial activities against three gram-positive strains (Methicillin resistant staphylococcus aureus (MRSA), Staphylococcus aureus, and Enterococcus faecalis) as well as three gram-negative strains (Pseudomonas aeruginosa, Klebsiella pneumonia, and Escherichia coli) through three standard methods including broth microdilution, agar-disc diffusion, and agar-well diffusion assays. Most of the compounds exhibited great to excellent anti-bacterial potencies against MRSA and S. aureus. Among the targeted compounds, derivative 7n exhibited great antibacterial potency, which was noticeably more potent than parent ciprofloxacin. Subsequently, a molecular docking study was performed for this compound to find out its probable binding mode with the active site of S. aureus DNA gyrase (PDB ID: 2XCT).

Mono- and bis-pyrazolophthalazines: Design, synthesis, cytotoxic activity, DNA/HSA binding and molecular docking studies.

In an attempt to find new potent cytotoxic compounds, several mono- and bis-pyrazolophthalazines 4a-m and 6a-h were synthesized through an efficient, one-pot, three- and pseudo five-component synthetic approach. All derivatives were evaluated for their in vitro cytotoxic activities against four human cancer cell lines of A549, HepG2, MCF-7, and HT29. Compound 4e showed low toxicity against normal cell lines (MRC-5 and MCF 10A, IC50 > 200 µM) and excellent cytotoxic activity against A549 cell line with IC50 value of 1.25 ± 0.19 µM, which was 1.8 times more potent than doxorubicin (IC50 = 2.31 ± 0.13 µM). In addition, compound 6c exhibited remarkable cytotoxic activity against A549 and MCF-7 cell lines (IC50 = 1.35 ± 0.12 and 0.49 ± 0.01 µM, respectively), more than two-fold higher than that of doxorubicin. The binding properties of the best active mono- and bis-pyrazolophthalazine (4e and 6c) with HSA and DNA were fully evaluated by various techniques including UV-Vis absorption, circular dichroism (CD), Zeta potential and dynamic light scattering analyses indicating interaction of the compounds with the secondary structure of HSA and significant change of DNA conformation, presumably via a groove binding mechanism. Additionally, molecular docking and site-selective binding studies confirmed the fundamental interaction of compounds 4e and 6c with base pairs of DNA. Compounds 4e and 6c showed promising features to be considered as potential lead structures for further studies in cancer therapy.

Design and synthesis of new imidazo[1,2-b]pyrazole derivatives, in vitro α-glucosidase inhibition, kinetic and docking studies.

A new series of imidazo[1,2-b]pyrazole derivatives 4a-o was designed, synthesized, and screened for in vitro α-glucosidase inhibitory activity. All compounds showed high inhibitory activity in the range of IC50 = 95.0 ± 0.5-372.8 ± 1.0 µM as compared to standard drug acarbose (IC50 = 750 ± 1.5 µM) and were also found to be non-cytotoxic. Among the synthesized compounds, the most potent compound was compound 4j with eightfold higher inhibitory activity compared to acarbose. Like acarbose, compound 4j inhibited α-glucosidase in a competitive mode. Molecular modeling studies of the most potent compounds 4j, 4f, 4o, and 4c were also conducted.

Design and synthesis of new fused carbazole-imidazole derivatives as anti-diabetic agents: In vitro α-glucosidase inhibition, kinetic, and in silico studies.

Twenty three fused carbazole-imidazoles 6a-w were designed, synthesized, and screened as new α-glucosidase inhibitors. All the synthesized fused carbazole-imidazoles 6a-w were found to be more active than acarbose (IC50 = 750.0 ±â€¯1.5 µM) against yeast α-glucosidase with IC50 values in the range of 74.0 ±â€¯0.7-298.3 ±â€¯0.9 µM. Kinetic study of the most potent compound 6v demonstrated that this compound is a competitive inhibitor for α-glucosidase (Ki value = 75 µM). Furthermore, the in silico studies of the most potent compounds 6v and 6o confirmed that these compounds interacted with the key residues in the active site of α-glucosidase.

Isoindolin-1-one derivatives as urease inhibitors: Design, synthesis, biological evaluation, molecular docking and in-silico ADME evaluation.

An efficient, one-pot and four-component synthesis of a new series of 2,3-disubstituted isoindolin-1-ones is described and their Jack bean urease inhibitory activities are evaluated. Heating a mixture of 1,1-bis(methylthio)-2-nitroethene, a 1,2-diamine, a 2-formylbenzoic acid and a primary amine in EtOH for 3.5 h afforded the corresponding 2,3-disubstituted isoindolin-1-ones in good to excellent yields. All sixteen synthesized isoindolin-1-one derivatives 5a-p showed urease inhibitory activity. Among them, 5c showed the most urease inhibitory activity (IC50 = 10.07 ±â€¯0.28 µM) being over 2-fold more potent than thiourea (IC50 = 22.01 ±â€¯0.10 µM) and 10-fold than hydroxyurea (IC50 = 100.00 ±â€¯0.02 µM) as the standard inhibitors, respectively. Also, results from molecular docking studies were in good agreement with those obtained from in vitro tests.

Quinazoline-based VEGFR-2 inhibitors as potential anti-angiogenic agents: A contemporary perspective of SAR and molecular docking studies.

Angiogenesis, the formation of new blood vessels from the existing vasculature, is pivotal in the migration, growth, and differentiation of endothelial cells in normal physiological conditions. In various types of tumour microenvironments, dysregulated angiogenesis plays a crucial role in supplying oxygen and nutrients to cancerous cells, leading to tumour size growth. VEGFR-2 tyrosine kinase has been extensively studied as a critical regulator of angiogenesis; thus, inhibition of VEGFR-2 has been widely used for cancer treatments in recent years. Quinazoline nucleus is a privileged and versatile scaffold with a broad range of pharmacological activity, especially in the field of tyrosine kinase inhibitors with more than twenty small molecule inhibitors approved by the US Food and Drug Administration in the last two decades. As of now, the U.S. FDA has approved eleven small chemical inhibitors of VEGFR-2 for various types of malignancies, with a prime example being vandetanib, a quinazoline derivative, which is a multi targeted kinase inhibitor used for the treatment of late-stage medullary thyroid cancer. Despite of prosperous discovery and development of VEGFR-2 down regulator drugs, there still exists limitations in clinical efficacy, adverse effects, a high rate of clinical discontinuation and drug resistance. Therefore, there is an urgent need for the design and synthesis of more selective and effective inhibitors to tackle these challenges. Through the gathering of this review, we have strived to broaden the extent of our view over the entire scope of quinazoline-based VEGFR-2 inhibitors. Herein, we give an overview of the importance and advancement status of reported structures, highlighting the SAR, biological evaluations and their binding modes.

Imidazo[1,2-c]quinazolines as a novel and potent scaffold of α-glucosidase inhibitors: design, synthesis, biological evaluations, and in silico studies.

α-Glucosidase inhibition is an approved treatment for type 2 diabetes mellitus (T2DM). In an attempt to develop novel anti-α-glucosidase agents, two series of substituted imidazo[1,2-c]quinazolines, namely 6a-c and 11a-o, were synthesized using a simple, straightforward synthetic routes. These compounds were thoroughly characterized by IR, 1H and 13C NMR spectroscopy, as well as mass spectrometry and elemental analysis. Subsequently, the inhibitory activities of these compounds were evaluated against Saccharomyces cerevisiae α-glucosidase. In present study, acarbose was utilized as a positive control. These imidazoquinazolines exhibited excellent to great inhibitory potencies with IC50 values ranging from 12.44 ± 0.38 µM to 308.33 ± 0.06 µM, which were several times more potent than standard drug with IC50 value of 750.0 ± 1.5 µM. Representatively, compound 11j showed remarkable anti-α-glucosidase potency with IC50 = 12.44 ± 0.38 µM, which was 60.3 times more potent than positive control acarbose. To explore the potential inhibition mechanism, further evaluations including kinetic analysis, circular dichroism, fluorescence spectroscopy, and thermodynamic profile were carried out for the most potent compound 11j. Moreover, molecular docking studies and in silico ADME prediction for all imidazoquinazolines 6a-c and 11a-o were performed to reveal their important binding interactions, as well as their physicochemical and drug-likeness properties, respectively.

The possible effect of microRNA-155 (miR-155) and BACE1 inhibitors in the memory of patients with down syndrome and Alzheimer's disease: Design, synthesis, virtual screening, molecular modeling and biological evaluations.

MiR-155 plays main roles in several physiological and pathological mechanisms, such as Down syndrome (DS), immunity and inflammation and potential anti-AD therapeutic target. The miR-155 is one of the overexpressed miRNAs in DS patients that contribute directly and indirectly to the onset or progression of the DS. Since the miR-155 can simultaneously reduce the translation of several genes at post-transcriptional levels, targeting the miR-155 might set the stage for the treatment of DS. One of the rational strategies in providing therapeutic interventions in this respect is to design and develop novel small molecules inhibiting the miR-155 function or biogenesis or maturation. In the present study, we aim to introduce small molecule compounds with the potential to inhibit the generation of the selectively miR-155 processing by employing computational drug design approaches, as well as in vitro studies. We designed and synthesized a novel series of imidazo[1,2-a]pyridines derivatives as new nonpeptic candidates for the treatment of DS with AD. The designed compounds were investigated for their BACE1 and miR-155 binder inhibitory potential in vitro and in cell. In addition, we present a systematic computational approach that includes 3 D modeling, docking-based virtual screening, and molecular dynamics simulation to identify Small - molecule inhibitors of pre-miR-155 maturation. To confirm the inhibitory potential of compound 8k on miR-155 maturation, qRT- PCR was performed. All our results confirm that compound 8k, in addition to being a good inhibitor of BACE1, can also be a good inhibitor of miR-155.Communicated by Ramaswamy H. Sarma.

Design, synthesis and evaluation of novel tetrahydropyridothienopyrimidin-ureas as cytotoxic and anti-angiogenic agents.

The novel derivatives of tetrahydropyridothienopyrimidine-based compounds have been designed and efficiently synthesized with good yields through seven steps reaction. The anticancer activity of compounds 11a-y has been evaluated against MCF-7, PC-3, HEPG-2, SW-480, and HUVEC cell lines by MTT assay. The target compounds showed IC50 values between 2.81-29.6 µg/mL and were compared with sorafenib as a reference drug. Among them, compound 11n showed high cytotoxic activity against four out of five examined cell lines and was 14 times more selective against MRC5. The flow cytometric analysis confirmed the induction of apoptotic cell death by this compound against HUVEC and MCF-7 cells. In addition, 11n caused sub-G1 phase arrest in the cell cycle arrest. Besides, this compound induced anti-angiogenesis in CAM assay and increased the level of caspase-3 by 5.2 fold. The western-blot analysis of the most active compound, 11n, revealed the inhibition of VEGFR-2 phosphorylation. Molecular docking study also showed the important interactions for compound 11n.

Design, synthesis, molecular docking, and in vitro α-glucosidase inhibitory activities of novel 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-a]pyrimidines against yeast and rat α-glucosidase.

In an attempt to find novel, potent α-glucosidase inhibitors, a library of poly-substituted 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-a]pyrimidines 3a-ag have been synthesized through heating a mixture of 2-aminobenzimidazoles 1 and α-azidochalcone 2 under the mild conditions. This efficient, facile protocol has been resulted into the desirable compounds with a wide substrate scope in good to excellent yields. Afterwards, their inhibitory activities against yeast α-glucosidase enzyme were investigated. Showing IC50 values ranging from 16.4 ± 0.36 µM to 297.0 ± 1.2 µM confirmed their excellent potency to inhibit α-glucosidase which encouraged us to perform further studies on α-glucosidase enzymes obtained from rat as a mammal source. Among various synthesized 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-a]pyrimidines, compound 3k exhibited the highest potency against both Saccharomyces cerevisiae α-glucosidase (IC50 = 16.4 ± 0.36 µM) and rat small intestine α-glucosidase (IC50 = 45.0 ± 8.2 µM). Moreover, the role of amine moiety on the observed activity was studied through substituting with chlorine and hydrogen resulted into a considerable deterioration on the inhibitory activity. Kinetic study and molecular docking study have confirmed the in-vitro results.

An efficient and targeted synthetic approach towards new highly substituted 6-amino-pyrazolo[1,5-a]pyrimidines with α-glucosidase inhibitory activity.

In an attempt to find novel α-glucosidase inhibitors, an efficient, straightforward reaction to synthesize a library of fully substituted 6-amino-pyrazolo[1,5-a]pyrimidines 3 has been investigated. Heating a mixture of α-azidochalcones 1 and 3-aminopyrazoles 2 under the mild condition afforded desired compounds with a large substrate scope in good to excellent yields. All obtained products were evaluated as α-glucosidase inhibitors and exhibited excellent potency with IC50 values ranging from 15.2 ± 0.4 µM to 201.3 ± 4.2 µM. Among them, compound 3d was around 50-fold more potent than acarbose (IC50 = 750.0 ± 1.5 µM) as standard inhibitor. Regarding product structures, kinetic study and molecular docking were carried out for two of the most potent ones.

New 6-amino-pyrido[2,3-d]pyrimidine-2,4-diones as novel agents to treat type 2 diabetes: A simple and efficient synthesis, α-glucosidase inhibition, molecular modeling and kinetic study.

A new series of 6-amino-pyrido[2,3-d]pyrimidine-2,4-dione derivatives 3a-3s were prepared via a facile and efficient reaction from α-azidochalcones and 6-amiouracils. The reactions were performed under mild conditions to produce the corresponding compounds in good to excellent yields. Obtained derivatives 3a-3s were evaluated for α-glucosidase inhibitory activity and all of them exhibited excellent in vitro yeast α-glucosidase inhibition with IC50 values ranging from 78.0 ±â€¯2.0 to 252.4 ±â€¯1.0 µM. For example, the most active compound 3o was around 10-fold more potent than acarbose, a standard drug (IC50 = 750.0 ±â€¯1.5 µM). Kinetic study of compound 3o revealed that it inhibited α-glucosidase in a competitive mode. Molecular modeling studies of the most active compounds 3o, 3i, 3e and 3m were also performed.