Design,synthesis, molecular modeling and biological evaluation of novel 1H-pyrazolo[3,4-b]pyridine derivatives as potential anticancer agents

In trying to develop new anticancer agents, a series of 1H-pyrazolo[3,4-b]pyridine derivatives was designed and synthesized. Fifteen compounds were evaluated in vitro for their anti-proliferative activity against HePG-2, MCF-7, HCT-116, and PC-3 cell lines. Additionally, DNA binding affinity of the synthesized derivatives was investigated as a potential mechanism for the anticancer activity using DNA/methyl green assay and association constants assay. Compounds 19, 20, 21, 24 and 25 exhibited good activity against the four cancer cells comparable to that of doxorubicin. Interestingly, DNA binding assay results were in agreement with that of the cytotoxicity assays where the most potent anticancer compounds showed good DNA binding affinity comparable to that of doxorubicin and daunorubicin. Furthermore, a molecular docking of the tested compounds was carried out to investigate their binding pattern with the prospective target, DNA (PDB-code: 152d).     

Design,synthesis and antiviral evaluation of novel acyclic phosphonate nucleotide analogs with triazolo[4,5-b]pyridine,imidazo[4,5-b]pyridine and imidazo[4,5-b]pyridin-2(3H)-one systems

Abstract

A new series of phosphonylated triazolo[4,5-b]pyridine (1-deaza-8-azapurine), imidazo[4,5-b]pyridine (1-deazapurine) and imidazo[4,5-b]pyridin-2(3H)-one (1-deazapurin-8-one) were synthesized from 2-chloro-3-nitropyridine and selected diethyl ?-aminoalkylphosphonates followed by reduction of the nitro group and cyclization. In the final step O,O-diethylphosphonates were transformed into the corresponding phosphonic acids. All synthesized compounds were evaluated in vitro for inhibitory activity against a broad variety of DNA and RNA viruses and their cytotoxic potencies were also established. Compound 12f showed marginal activity against cytomegalovirus Davis strain (EC₅₀?=?76.47?μM) in human embryonic lung (HEL) cells while compounds 10g (EC₅₀?=?52.53?μM) and 12l (EC₅₀?=?61.70?μM) were minimally active against the varicella-zoster virus Oka strain in HEL cells. Compounds under investigation were not cytotoxic at the maximum concentration evaluated (100?µM).     

Discovery of a highly potent,selective and novel CDK9 inhibitor as an anticancer drug candidate

A series of novel hybrid structure derivatives, containing both LEE011 and Cabozantinib pharmacophore, were designed, synthesized and evaluated. Surprisingly, a compound 4d was discovered that highly exhibited effective and selective activity of CDK9 inhibition with IC₅₀ = 12 nM. It effectively induced apoptosis in breast and lung cancer cell lines at nanomolar level. Molecular docking of 4d to ATP binding site of CDK9 kinase demonstrated a new hydrogen bonding between F atom of 4-(3-fluorobenzyloxy) group and ASN116 residue, compared with the positive control, LEE011. The compound 4d could block the cell cycle both in G0/G1 and G2/M phase to prevent the proliferation and differentiation of cancer cells. Mice bared-breast cancer treated with compound 4d showed significant suppression of cancer with low toxicity. Taken together, this novel compound 4d could be a promising drug candidate for clinical application.     

Design, synthesis and anticancer activity of novel dihydrobenzofuro[4,5-b][1,8]naphthyridin-6-one derivatives

On the basis of the chemical structures of psorospermin with a xanthone template and acronycine derivatives with an acridone template, rac-1 and rac-2 constructed on an 1,2-dihydrobenzofuro[4,5-b][1,8]naphthyridin-6(11H)-one scaffold were designed and synthesized as potential anticancer agents. Their anticancer activities were evaluated against five human cancer cell lines. Rac-2 showed similar anticancer activity to doxorubicin and rac-1 exhibited even higher anticancer activity against LNCaP (IC(50)=0.14 μM), DU145 (IC(50)=0.15 μM), PC3 (IC(50)=0.30 μM) and MCF-7 (IC(50)=0.26 μM) cancer lines than doxorubicin and rac-2. Also, rac-1 revealed very potent anticancer activity (IC(50)=0.15 μM) against MCF-7/ADR cell (doxorubicin-resistant breast cancer cell) lines and induced G2/M phase arrest of the cell cycle in MCF-7/ADR cells.     

Design,synthesis and molecular modeling study of certain 4-Methylbenzenesulfonamides with CDK2 inhibitory activity as anticancer and radio-sensitizing agents

Two series of 2-aminopyridine derivatives 6-17 and tyrphostin AG17 analogs 18-22 bearing 4-methylbenzenesulfonamide moiety were designed and synthesized as anticancer compounds. The synthesized compounds were biologically evaluated for their cytotoxic activity against human breast cancer cell line MCF-7. From 2-aminopyridine and tyrphostin AG17 series, compounds 14, 16 and 20 showed the best activities with IC₅₀ values of 20.4, 18.3 and 26.3 µM, respectively compared to E7070 IC₅₀ 36.3 µM. Further biological evaluation of 14, 16 and 20 against cyclin dependent kinase-2 (CDK2) revealed good inhibitory activity with IC₅₀ of 2.53, 1.79 and 2.92 µM, respectively compared to roscovitine IC₅₀ 0.43 µM. Additionally, capability of γ-radiation to augment the cytotoxic activity of 14, 16 and 20 was studied and showed a dramatic increase in the cell killing effect at lower concentrations after irradiation. Docking was used to investigate the possible binding modes of compounds 14, 16 and 20 inside the active site of CDK2 enzyme.     

Design,synthesis and molecular docking of novel pyrazolo[1,5-a][1,3,5]triazine derivatives as CDK2 inhibitors

Cyclin Dependent Kinases CDKs unpredictable activity has been accounted for a wide assortment of human malignancies, so it might be conceivable to design pharmacologically relevant ligands that go about as specific and potent inhibitors of CDK2 action. In this respect, a series of novel pyrazolo[1,5-a][1,3,5]triazine derivatives were designed, synthesized and evaluated for CDK2 enzyme inhibitory and anticancer activity. Compounds 9f and 10c showed best CDK2 inhibition among the newly synthesized compounds, with percent inhibition at 82.38%, and 81.96% against CDK2 and IC₅₀ of 1.85 and 2.09 µM, respectively. Additionally, the newly synthesized compounds were tested for their antiproliferative activity against 60 NCI cell lines. Molecular docking revealed the binding mode of these new compounds into the roscovitine binding site of CDK2 enzyme (PDB code: 3ddq). Conclusively, pyrazolotriazine derivatives represent a talented starting point for further study as anticancer drug.     

Synthesis and biological evaluation of novel alkyl amide functionalized trifluoromethyl substituted pyrazolo[3,4-b]pyridine derivatives as potential anticancer agents

A series of novel alkyl amide functionalized trifluoromethyl substituted pyrazolo[3,4-b]pyridine derivatives 5, 6 and 7 were prepared starting from 6-phenyl-4-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine 3 via selective N-alkylation, followed by reaction with different primary aliphatic amines, cyclic secondary amines or l-amino acids under different set of conditions. All the synthesized compounds 5, 6 and 7 were screened for anticancer activity against four cancer cell lines such as A549—Lung cancer (CCL-185), MCF7—Breast cancer (HTB-22), DU145—Prostate cancer (HTB-81) and HeLa—Cervical cancer (CCL-2). The compounds 5i and 6e are found to have promising bioactivity at micro molar concentration.     

Design, synthesis and bioevaluation of dihydropyrazolo[3,4-b]pyridine and benzo[4,5]imidazo[1,2-a]pyrimidine compounds as dual KSP and Aurora-A kinase inhibitors for anti-cancer agents

Four series of dihydropyrazolo[3,4-b]pyridines and benzo[4,5]imidazo[1,2-a]pyrimidines were designed and synthesized as dual KSP and Aurora-A kinase inhibitors for anti-cancer agents by introducing some fragments of Aurora-A kinase inhibitors into our KSP inhibitor CPUYL064. A total of 19 target compounds were evaluated by two related enzyme inhibition assays and a cytotoxicity assay in vitro. The results showed that some target compounds could inhibit both enzymes, and several of them showed significant inhibition activity against HCT116 cell line. Despite showing moderate KSP and Aurora-A kinase inhibition, the lead compounds 6a and 6e displayed significant cytotoxic activity in the micromolar range, especially against the HCT116 cell line and HepG2 cell line. The results may be useful for developing a new class of inhibitors having a dual function, KSP inhibition and Aurora-A kinase inhibition, for the treatment of cancer.     

Design and synthesis of novel pyrrolo[2,3-b]pyridine derivatives targeting V600EBRAF

Several pyrrolo[2,3-b]pyridine-based B-RAF inhibitors are well known and some of them are currently FDA approved as anticancer agents. Based on the structure of these FDA approved ^V600EB-RAF inhibitors, two series of pyrrolo[2,3-b]pyridine scaffold were designed and synthesized in attempt to develop new potent ^V600EB-RAF inhibitors. The 38 synthesized compounds were biologically evaluated for their ^V600EB-RAF inhibitory effect at single dose (10 μM). Compounds with high percent inhibition were tested to determine their IC₅₀ over ^V600EB-RAF. Compounds 34e and 35 showed the highest inhibitory effect with IC₅₀ values of 0.085 µM and 0.080 µM, respectively. Headed for excessive biological evaluation, the synthesized derivatives were tested over sixty diverse human cancer cell lines. Only compound 35 emerged as a potent cytotoxic agent against different panel of human cancer cell lines.     

Design,synthesis and biological evaluation of certain CDK2 inhibitors based on pyrazole and pyrazolo[1,5-a] pyrimidine scaffold with apoptotic activity

Different series of novel pyrazole and pyrazolo[1,5-a] pyrimidine derivatives (2a-g), (3a-c), (7a-d) and (10a-e) were designed, synthesized and evaluated for their ability to inhibit CDK2/cyclin A2 enzyme in vitro. In addition, the cytotoxicity of the newly synthesized compounds was screened against four different human cancer cell lines. The CDK2/cyclin A2 enzyme inhibitory activity revealed that compounds (2d) and (2 g) are among the most active with inhibitory activity values of 60% and 40%, respectively, while compounds (7d) and (10b) exhibited the highest activity among the newly synthesized derivatives against four tumor cell lines (HepG2, MCF-7, A549 and Caco2) with IC50 values 24.24, 14.12, 30.03 and 29.27 μM and 17.12, 10.05, 29.95 and 25.24 μM, respectively. Flow cytometry cell cycle assay was carried for compounds (7d) and (10b) to investigate their apoptotic activity. The obtained results revealed that they induced cell-cycle arrest in the G0-G1phase and reinforced apoptotic DNA fragmentation. Molecular modeling studies have been carried out to gain further understanding the binding mode of the target compounds together with field alignment to define the similar field properties.     

Synthesis of 3,5-bis(2-indolyl)pyridine and 3-[(2-indolyl)-5-phenyl]pyridine derivatives as CDK inhibitors and cytotoxic agents

We here report the synthesis and biological evaluation of new 3,5-bis(2-indolyl)pyridine and 3-[(2-indolyl)-5-phenyl]pyridine designed as potential CDK inhibitors. Indole, 5-hydroxyindole, and phenol derivatives were used to generate three substitutions of the pyridine. The resulting skeletons were successively exploited to introduce various dimethylaminoalkyl side chains by Williamson type reactions. The synthesis includes Stille or Suzuki type reactions, which were realized on the 3,5-dibromopyridine. The preparation and the use of stannylindoles in mono or bis cross-coupling reactions were also described and each step was optimized and detailed. Kinase assays were realized and shown that nude compounds 7, 18, and 25 inhibited CDK1 in the 0.3–0.7 micromolar range with a good selectivity over GSK-3. Cytotoxicity against CEM human leukemia cells was evaluated with IC₅₀ values in the 5–15 micromolar range. Precise structure–activity relationships were delineated. Molecular modeling and docking solutions were proposed to complete the studies and to explain the observed SAR in the CDK assays.     

Synthesis and biological evaluation of novel 5,6-dihydropyrimido[4,5-f]quinazoline derivatives as potent CDK2 inhibitors

As serine/threonine kinase, the cyclin dependent kinase 2 (CDK2) is a promising target for various diseases such as cerebral hypoxia, cancer, and neurodegenerative diseases. Here we reported the structure-based synthesis and biological evaluation of novel 5,6-dihydropyrimido[4,5-f]quinazoline derivatives as CDK2 inhibitors, which exhibited potent CDK2 inhibitory activities, as well as anticancer activities in low concentration against two human cancer cell lines (MCF-7 and HCT116). In particular, compounds 11a and 11f (IC₅₀ values of 0.11 and 0.09?μM for CDK2, respectively) have demonstrated significantly inhibitory potency against CDK2 and have showed great inhibitory activities against MCF-7 and HCT116 cell lines.     

Design,synthesis and biological evaluation of novel 3H-imidazole [4,5-b] pyridine derivatives as selective mTOR inhibitors

A series of 3H-imidazo [4,5-b] pyridines derivatives were designed and synthesized as selective mTOR inhibitors. The systematic optimization of the molecules resulted in the identification of two compounds 10d and 10n with nanomolar mTOR inhibitory activity and selectivity over PI3Kα. Besides, compounds 10d and 10n demonstrated attractive potency against human breast cancer cells (MCF-7) and human ovarian cancer cell (A2780).     

Discovery of novel potent GPR40 agonists containing imidazo[1,2-a]pyridine core as antidiabetic agents

Free fatty acid receptor 1 (FFA1 or GPR40) has been studied for many years as a target for the treatment of type 2 diabetes mellitus. In order to increase potency and reduce hepatotoxicity, a series of novel compounds containing imidazo[1,2-a]pyridine scaffold as GPR40 agonist were synthesized. Compound I-14 was identified as an effective agonist as shown by the conspicuous drop in blood glucose in normal and diabetic mice. It had no risk of hepatotoxicity compared with TAK-875. Moreover, good pharmacokinetic (PK) properties of I-14 were observed (CL = 27.26 ml/h/kg, t_1/2 = 5.93 h). The results indicate that I-14 could serve as a possible candidate to treat diabetes.     

Synthesis,molecular modeling and biological evaluation of new pyrazolo[3,4-b]pyridine analogs as potential antimicrobial,antiquorum-sensing and anticancer agents

New pyrazolo[3,4-b]pyridine analogs 2–9 were synthesized and subjected to antimicrobial testing toward chosen Gram-negative bacteria, Gram-positive bacteria and fungi. Compound 2 exhibited potent and extended-spectrum antimicrobial activity. Further, 6 and 9c demonstrated remarkable and extended-spectrum antibacterial activity. Antiquorum-sensing activity of the new members was tested over C. violaceum, whereas 9c demonstrated strong efficacy, while 2, 8b and 9b displayed moderate efficacy. In vitro anticancer assay toward HepG2, MCF-7 and Hela cancer cells manifested that 2 and 9c are powerful and extended-spectrum anticancer agents. Additionally, 8a, 8b and 9b showed excellent activity toward the three cancer cells. In vivo anticancer assay over EAC in mice indicated that 2 and 9c have the greatest activity. Moreover, cytotoxicity assay over WISH and W138 normal cells clarified that the checked analogs possess weak cytotoxicity toward the two normal cells. DNA-binding affinity was also tested, whereas 2, 3, 8b, 9b and 9c demonstrated great affinity. Molecular modeling studies revealed that the investigated compounds bind to DNA through intercalation similarly to doxorubicin. In silico studies revealed that the new members are anticipated to show excellent intestinal absorption.     

Hit generation and exploration: imidazo[4,5-b]pyridine derivatives as inhibitors of Aurora kinases

A hit generation and exploration approach led to the discovery of 31 (2-(4-(6-chloro-2-(4-(dimethylamino)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)piperazin-1-yl)-N-(thiazol-2-yl)acetamide), a potent, novel inhibitor of Aurora-A, Aurora-B and Aurora-C kinases with IC(50) values of 0.042, 0.198 and 0.227microM, respectively. Compound 31 inhibits cell proliferation and has good microsomal stability.     

Design,synthesis, and structure-activity relationships of novel imidazo[4,5-c]pyridine derivatives as potent non-nucleoside inhibitors of hepatitis C virus NS5B

The hepatitis C virus (HCV) NS5B polymerase is an attractive target for the development of novel and selective inhibitors of HCV replication. In this paper, the design, synthesis, and preliminary SAR studies of novel inhibitors of HCV NS5B polymerase based on the structure of tegobuvir have been described. The efforts to optimize the antiviral potency and reduce the treatment side effects with respect to genotype 1b resulted in the discovery of compound 3, which exhibited an EC₅₀ of 1.163?nM and a CC₅₀ >200?nM in a cell-based HCV replicon system assay. Additionally, testing for inhibition of the hERG channel showed a marked improvement over tegobuvir and the pharmacokinetic properties of compound 3 indicated that it was worthy of further investigation as a non-nucleoside inhibitor of HCV NS5B polymerase.     

Design and synthesis of novel oridonin analogues as potent anticancer agents

To identify anticancer agents with higher potency and lower toxicity, a series of oridonin derivatives with substituted benzene moieties at the C17 position were designed, synthesised, and evaluated for their antiproliferative properties. Most of the derivatives exhibited antiproliferative effects against AGS, MGC803, Bel7402, HCT116, A549, and HeLa cells. Compound 2p (IC_50?=?1.05?µM) exhibited the most potent antiproliferative activity against HCT116 cells; it was more potent than oridonin (IC₅₀?=?6.84?µM) and 5-fluorouracil (5-FU) (IC_50?=?24.80?µM). The IC₅₀ value of 2p in L02 cells was 6.5-fold higher than that in HCT116 cells. Overall, it exhibited better selective antiproliferative activity and specificity than oridonin and 5-FU. Furthermore, compound 2p arrested HCT116 cells at the G2 phase of the cell cycle and increased the percentage of apoptotic cells to a greater extent than oridonin.     

Design and synthesis of aminocoumarin derivatives as DPP-IV inhibitors and anticancer agents

DPP-IV “a moonlighting protein” has immerged as promising pathway to control Type 2 diabetes as well as found to play key role in earlier stages of cancer. Here we have reported design, synthesis and applications of aminocoumarin derivatives as DPP-IV inhibitors. Compounds have been synthesized and studied for their DPP-IV inhibition activity. Three compounds have shown moderate inhibition at 100 µM concentration. All compounds were also screened for their anticancer activity against A549 (Lung cancer cell line), MCF-7 (Breast cancer cell line) using MTT assay. One of the compounds has shown very good anticancer activity with IC₅₀ value 24 ± 0.1 nM against A549 cell line.     

Synthesis and evaluation of pyrazolo[3,4-b]pyridine CDK1 inhibitors as anti-tumor agents

A series of 3,5-disubstituted pyrazolo[3,4-b]pyridine cyclin-dependent kinase (CDK) inhibitors was synthesized. These compounds showed potent and selective CDK inhibitory activities and inhibited in vitro cellular proliferation in cultured human tumor cells. Selected compounds were evaluated in an in vivo tumor xenograft model. The synthesis and biological evaluation of these pyrazolo[3,4-b]pyridines and related compounds are reported.