Design,synthesis and molecular modeling study of certain VEGFR-2 inhibitors based on thienopyrimidne scaffold as cancer targeting agents

Different series of novel thieno [2,3-d]pyrimidine derivative (9a-d,10a-f,l,m and 15a-m) were designed, synthesized and evaluated for their ability to in vitro inhibit VEGFR-2 enzyme. Also, the cytotoxicity of the final compounds was tested against a panel of 60 different human cancer cell lines by NCI. The VEGFR-2 enzyme inhibitory results revealed that compounds 10d, 15d and 15 g are among the most active inhibitors with IC₅₀ values of 2.5, 5.48 and 2.27 µM respectively, while compound 10a remarkably showed the highest cell growth inhibition with mean growth inhibition (GI) percent of 31.57%. It exhibited broad spectrum anti-proliferative activity against several NCI cell lines specifically on human breast cancer (T7-47D) and renal cancer (A498) cell lines of 85.5% and 77.65% inhibition respectively. To investigate the mechanistic aspects underlying the activity, further biological studies like flow cytometry cell cycle together with caspase-3 colorimetric assays were carried on compound 10a. Flow cytometric analysis on both MCV-7 and PC-3 cancer cells revealed that it induced cell-cycle arrest in the G0-G1phase and reinforced apoptosis via activation of caspase-3. Furthermore, molecular modeling studies have been carried out to gain further understanding of the binding mode in the active site of VEGFR-2 enzyme and predict pharmacokinetic properties of all the synthesized inhibitors.     

Synthesis and anticancer activities of thieno[3,2-d]pyrimidines as novel HDAC inhibitors

A series of thieno[3,2-d]pyrimidines bearing a hydroxamic acid moiety as novel HDAC inhibitors were designed and synthesized. The structures of the new synthesized compounds were confirmed using IR, ¹H, ¹³C NMR spectrum. Compounds 11–13 showed potent inhibitory activities against HDACs with IC₅₀ values at 0.38, 0.49 and 0.61 μM. Most of target compounds displayed strong anti-proliferative activity by a MTT assay on three human cancer cell lines including HCT-116, MCF-7 and HeLa. Compound 11, having potent inhibitory activities against HDACs, induced apoptosis and G2/M cell cycle arrest in HCT-116 cell line.     

Synthesis and biological evaluation of novel steroidal 5α,8α-epidioxyandrost-6-ene-3β-ol-17-(O-phenylacetamide)oxime derivatives as potential anticancer agents

Inspired by the significant anti-cancer activity of our previously screened natural ergosterol peroxide (EP, 1), we synthesized and characterized a series of novel 5α,8α-epidioxyandrost-3β-ol-17-(O-phenylacetamide)oxime derivatives (9a–o). The anti-proliferative activity of the synthesized compounds against human hepatocellular carcinoma cells (HepG2, Sk-Hep1) and human breast cancer cells (MCF-7, MDA-MB231) were investigated. Compounds 9d, 9f, 9h, 9j and 9m displayed good anti-proliferative activity (most IC₅₀ < 20 μM) in vitro. Furthermore, fluorescence imaging showed that the designed coumarin-9d conjugate (12) localized mainly in mitochondria, leading to enhanced anticancer activities over the parent structure.     

Design,synthesis and biological evaluation of novel β-pinene-based thiazole derivatives as potential anticancer agents via mitochondrial-mediated apoptosis pathway

A series of novel β-pinene-based thiazole derivatives were synthesized and characterized by HRMS, ¹H NMR, and ¹³C NMR analyses as potential antineoplastic agents. Derivatives were evaluated for their anticancer activities in vitro, and the data manifested that most target compounds showed potent anti-proliferative activities against three human cancer cell lines. Especially, compound 5g displayed excellent cytotoxic activity against Hela, CT-26, and SMMC-7721 cell lines with IC₅₀ values of 3.48 ± 0.14, 8.84 ± 0.16, and 6.69 ± 0.15 µM, respectively. To determine the underlying mechanism of compound 5g on cell viability, DAPI staining, Annexin-V/PI staining, JC-1 staining, DCFDA staining, and Western blot analysis were performed. Our data showed that compound 5g inhibited cell proliferation by inducing apoptosis and cell cycle arrest of Hela cells at the G0/G1 phase in a dose dependent manner. Further studies revealed that compound 5g enhanced levels of reactive oxygen species (ROS), caused a decrease in mitochondrial membrane potential, increased the release of mitochondrial cytochrome C, and affected the expression of Bax, Bcl-2, caspase-3 and caspase-9. Thus, our findings indicated that compound 5g induced apoptosis in Hela through ROS-mediated mitochondrial dysfunction signaling pathways.     

Design,synthesis and biological evaluation of ring A modified 11-keto-boswellic acid derivatives as Pin1 inhibitors with remarkable anti-prostate cancer activity

Pin1 (Protein interaction with never in mitosis A1) is a validated molecular target for anticancer drug discovery. Herein, we reported the design, synthesis, and structure-activity relationship study of novel ring A modified AKBA (3-acetyl-11-keto-boswellic acid) derivatives as Pin1 inhibitors. Most compounds showed superior Pin1 inhibitory activities to AKBA. One of the most promising compounds, 10a, potently inhibited Pin1 with IC₅₀ value of 0.46?μM, while it displayed excellent anti-proliferative effect against prostate cancer cells PC-3 with GI₅₀ value of 1.82?μM. Structure-activity relationship indicated that reasonable structural modifications in ring A had significant impact on improving activity. Further mechanism research revealed that 10a decreased the level of Cyclin D1 and caused cell cycle arrest at G0/G1 phase in PC-3 cancer cells. Thus, compound 10a may serve as potential anti-prostate cancer agent for further investigation through Pin1 inhibition.     

Design,synthesis and evaluation of acridine derivatives as multi-target Src and MEK kinase inhibitors for anti-tumor treatment

Clinical studies have shown enhanced anticancer effects of combined inhibition of Src and MEK kinases. Development of multi-target drugs against Src and MEK is of potential therapeutic advantage against cancers. As a follow-up of our previous studies, and by using molecular docking method, we designed and synthesized a new series of 9-anilinoacridines containing phenyl-urea moieties as potential novel dual Src and MEK inhibitors. The anti-proliferative assays against K562 and HepG-2 tumor cells showed that most of the derivatives displayed good cytotoxicity in vitro. In particular, kinase inhibition assays showed that compound 8m inhibited Src (59.67%) and MEK (43.23%) at 10 μM, and displayed moderate inhibitory activity against ERK and AKT, the downstream effectors of both Src and MEK. Moreover, compound 8m was found to induce K562 cells apoptosis. Structure–activity relationships of these derivatives were analyzed. Our study suggested that acridine scaffold, particularly compound 8m, is of potential interest for developing novel multi-target Src and MEK kinase inhibitors.     

Design,synthesis and evaluation of novel sophoridinic imine derivatives containing conjugated planar structure as potent anticancer agents

Based on our previous study and the binding mode of camptothecin with Topo I, a series of novel sophoridine imine derivatives containing conjugated planar structure were designed, synthesized and tested for their in vitro anticancer activity. The results showed that most of the derivatives displayed potent activity. In particular, compounds 10b exhibited excellent anti-proliferative activities with IC₅₀ 5.7?µM and 8.5?µM against HepG-2 and HeLa cell lines, respectively. Molecular docking studies revealed that the introduction of conjugated planar structure could form π-π stacking interaction with DNA, leading to the improvement of biological activity. Its mode of action was to inhibit the activity of DNA Topo I, followed by the G0/G1 phase arrest. This work provides a theoretical basis for structural optimizations and exploring anticancer pathways of this kind of compound and 10b could emerge as promising lead compounds for the development of novel Topo I inhibitors.     

Design,synthesis, docking studies and biological evaluation of novel chalcone derivatives as potential histone deacetylase inhibitors

A group of novel chalcone derivatives comprising hydroxamic acid or 2-aminobenzamide group as zinc binding groups (ZBG) were synthesized. The structure of the prepared compounds was fully characterized by IR, NMR and elemental microanalyses. Most of the tested compounds displayed strong to moderate HDAC inhibitory activity. Some of these compounds showed potent anti-proliferative activity against human HepG2, MCF-7 and HCT-116 cell lines. In particular, compounds 4a and 4b exhibited significant anti-proliferative activity against the three cell lines compared to SAHA as reference drug and displayed promising profile as anti-tumor candidates. The results indicated that these chalcone derivatives could serve as a promising lead compounds for further optimization as antitumor agents.     

Discovery of novel histone lysine methyltransferase G9a/GLP (EHMT2/1) inhibitors: Design,synthesis, and structure-activity relationships of 2,4-diamino-6-methylpyrimidines

The discovery and optimization of a novel series of G9a/GLP (EHMT2/1) inhibitors are described. Starting from known G9a/GLP inhibitor 5, efforts to explore the structure-activity relationship and optimize drug properties led to a novel compound 13, the side chain of which was converted to tetrahydroazepine. Compound 13 showed increased G9a/GLP inhibitory activity compared with compound 5. In addition, compound 13 exhibited improved human ether-a-go-go related gene (hERG) inhibitory activity over compound 5 and also improved pharmacokinetic profile in mice (oral bioavailability: 17 to 40%). Finally, the co-crystal structure of G9a in complex with compound 13 provides the basis for the further development of tetrahydroazepine-based G9a/GLP inhibitors.     

Design,synthesis and biological evaluation of millepachine derivatives as a new class of tubulin polymerization inhibitors

A series of novel tubulin polymerization inhibitors (9a–9p) have been synthesized and evaluated for their in vitro and in vivo biological activities. Among these compounds, 9e displayed strong antiproliferative activity against several tumor cell lines (IC₅₀ = 0.15–0.62 μM). Compound 9e was also shown to arrest cells in the G2/M phase of the cell cycle and inhibit the polymerization of tubulin. Molecular docking studies suggested that 9e binds into the colchicine binding site of tubulin. In xenograft experiments, 9e exerted more potent anticancer effect than anticancer drug taxol against the H460 Human lung carcinoma in BALB/c nude mice. In summary, these findings suggest that 9e is a promising new antimitotic compound for the potential treatment of cancer.     

Anti-tumor activity evaluation of novel tubulin and HDAC dual-targeting inhibitors

Histone deacetylases (HDACs) have proven to be promising targets for the development of anti-cancer drugs. In this study, we reported a series of novel chalcone based tubulin and HDAC dual-targeting inhibitors. Three compounds inhibited the activities of HDAC and tubulin polymerization simultaneously and displayed anti-proliferative activities toward eleven human tumor cell lines. Compound 8a remarkably induced growth inhibition, apoptosis and G2/M phase arrest of A549 tumor cells. Finally, the inhibitory activities of 8a against HDAC6 and tubulin were rationalized by molecular docking studies.     

A fission yeast platform for heterologous expression of mammalian adenylyl cyclases and high throughput screening

The fission yeast Schizosaccharomyces pombe uses a cAMP signaling pathway to link glucose-sensing to Protein Kinase A activity in order to regulate cell growth, sexual development, gluconeogenesis, and exit from stationary phase. We previously used a PKA-repressed fbp1-ura4 reporter to conduct high throughput screens (HTSs) for inhibitors of heterologously-expressed mammalian cyclic nucleotide phosphodiesterases (PDEs). Here, we describe the successful expression of all ten mammalian adenylyl cyclase (AC) genes, along with the human GNAS Gα_s gene. By measuring expression of an fbp1-GFP reporter together with direct measurements of intracellular cAMP levels, we can detect both basal AC activity from all ten AC genes as well as GNAS-stimulated activity from eight of the nine transmembrane ACs (tmACs; AC2-AC9). The ability to use this platform to conduct HTS for novel chemical probes that reduce PKA activity was demonstrated by a pilot screen of the LOPAC®¹²⁸⁰ library, leading to the identification of diphenyleneiodonium chloride (DPI) as an inhibitor of basal AC activity. This screening technology could open the door to the development of therapeutic compounds that target GNAS or the ACs, an area in which there is significant unmet need.     

Design,synthesis and cytotoxic activities of scopoletin-isoxazole and scopoletin-pyrazole hybrids

12 novel scopoletin-isoxazole and scopoletin-pyrazole hybrids were designed, synthesized and their chemical structures were confirmed by HR-MS, IR, ¹H NMR and ¹³C NMR spectra. The anticancer activities of the newly synthesized compounds were evaluated in vitro against three human cancer cell lines including HCT-116, Hun7 and SW620 by MTT assay. The screening results showed that six compounds (9a, 9c, 9d, 12a, 18b and 18d) exhibited potent cytotoxic activities with IC₅₀ values below 20 μM. Besides, we have further evaluated the growth inhibitory activities of six compounds against the human normal tissue cell lines HFL-1. Especially, compound 9d displayed significant anti-proliferative activity with IC₅₀ values ranging from 8.76 μM to 9.83 μM and weak cytotoxicity with IC₅₀ value of 90.9 μM on normal cells HFL-1, which suggested that isoxazole-based hybrids of scopoletin were an effective chemical modification to improve the anticancer activity of scopoletin.     

Synthesis and biological evaluation of novel benzofuroxan-based pyrrolidine hydroxamates as matrix metalloproteinase inhibitors with nitric oxide releasing activity

On the basis of the strategy of “multifunctional drugs”, a series of novel matrix metalloproteinase inhibitors (MMPIs) containing benzofuroxan scaffold as a nitric oxide donor were designed, synthesized and evaluated. All synthesized compounds, especially 16a, exhibited potent MMP-2,9 inhibitory activities, anti-proliferative activities and could produce high levels of NO in Hela cells. They were also evaluated for both of their anti-invasion and anti-angiogenesis effects. Furthermore, compared with LY52, 16a demonstrated competitive antitumor activity in vivo. These hybrid NO-MMPIs might offer suitable scaffolds to develop valuable MMP inhibitors for the further discovery of novel anti-cancer drugs.     

Quinazoline Based HSP90 Inhibitors: Synthesis,Modeling Study and ADME Calculations Towards Breast Cancer Targeting

A new 2-thioquinazolinones series was designed and synthesized as HSP90 inhibitors based on the structure of hit compound VII obtained by virtual screening approach. Their in vitro anti-proliferative activity was evaluated against three human cancer cell lines rich in HSP90 namely; colorectal carcinoma (HCT-116), and cervical carcinoma (Hela), breast carcinoma (MCF-7). Compounds 5a, 5d, 5e and 9h showed a significant broad spectrum anti-proliferative activity against all tested cell lines. They were characterized by potent effect against breast cancer in particular with IC₅₀ of 11.73, 8.56, 7.35 and 9.48 μM, respectively against Doxorubicin (IC₅₀ 4.17 μM). HSP90 ATPase activity inhibition assay were conducted where compound 5d exhibited the best IC₅₀ with 1.58 μM compared to Tanespimycin (IC₅₀ = 2.17 μM). Compounds 5a and 9h showed higher IC₅₀ values of 3.21 and 3.41 μM, respectively. The effects of 5a, 5d and 9h on Her2 (a client proteins of HSP90) and HSP70 were evaluated in MCF-7 cells. All tested compounds were found to reduce Her2 protein expression levels and induce Hsp70 protein expression levels significantly, emphasizing that antibreast cancer effect is a consequence of HSP90 chaperone inhibition. Cell cycle analysis of MCF-7 cells treated with 5d showed cell cycle arrest at G2/M phase 38.89% and pro-apoptotic activity as indicated by annexin V-FITC staining by 22.42%. Molecular docking studies suggested mode of interaction to HSP90 via hydrogen bonding. ADME properties prediction of the active compounds suggested that they could be used as orally absorbed anticancer drug candidates.     

Anti-proliferative effect of chalcone derivatives through inactivation of NF-κB in human cancer cells

To investigate the anti-proliferative effect of NF-κB inhibitor, a series of analogs of (E)-1-(2-hydroxy-6-(isopentyloxy)phenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (5a) were prepared and evaluated for their NF-κB inhibition and anti-proliferative activity against various human cancer cell lines. Compounds (E)-1-(2-(3,3-dimethylbutoxy)-6-hydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (5e) and (E)-4-(3-(2-(3,3-dimethylbutoxy)-6-hydroxyphenyl)-3-oxoprop-1-enyl)benzenesulfonamide (5p) showed good NF-κB inhibition as well as potent anti-proliferative activity. SAR studies showed that all the compounds with potent or moderate NF-κB inhibition displayed good anti-proliferative activity. All the analogs (5b–r) maintained a good correlation between their NF-κB inhibition and anti-proliferative activity though the extent is not directly proportional to each other.     

Identification of 10-dehydrooxyglycyuralin E as a selective human estrogen receptor alpha partial agonist

Selective estrogen receptor modulators (SERMs) act as either agonist or antagonist of estrogen receptor (ER) in a tissue selective manner and have been used in several diseases such as breast cancer, postmenopausal syndrome, osteoporosis, and cardiovascular diseases. However, current SERMs may also increase the risk of serious side effects and trigger drug resistance. Herein, a screening program, that was designed to search for novel SERMs, resulted in the identification of a series of 2-arylbenzofuran-containing compounds that are ligands for ERα, when applying the Gaussia-luciferase reporter assay. One of these compounds, 10-dehydrooxyglycyuralin E (T9) was chemically synthesized. T9 showed anti-estrogenic/proliferative activity in ERα-positive breast cancer cells. Pretreatment of T9 prevented the mRNA expression of GREB1, which is an estrogen response gene. Furthermore, by an in silico docking simulation study we demonstrated that T9 showed interactions directly to ERα. Taken together, these results demonstrated that T9 is a candidate of SERMs and a useful seed compound for the foundation of the selective activity of SERMs.     

Ethyl 2-(benzylidene)-7-methyl-3-oxo-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate analogues as a new scaffold for protein kinase casein kinase 2 inhibitor

Protein kinase casein kinase 2 (PKCK2) is a constitutively active, growth factor-independent serine/threonine kinase, and changes in PKCK2 expression or its activity are reported in many cancer cells. To develop a novel PKCK2 inhibitor(s), we first performed cell-based phenotypic screening using 4000 chemicals purchased from ChemDiv chemical libraries (2000: randomly selected; 2000: kinase-biased) and performed in vitro kinase assay-based screening using hits found from the first screening. We identified compound 24 (C24)[(Z)-ethyl 5-(4-chlorophenyl)-2-(3,4-dihydroxybenzylidene)-7-methyl-3-oxo-3,5-dihydro-2H-thiazolo[3,2-a] pyrimidine-6-carboxylate] as a novel inhibitor of PKCK2 that is more potent and selective than 4,5,6,7-tetrabromobenzotriazole (TBB). In particular, compound 24 [half maximal inhibitory concentration (IC₅₀) = 0.56 μM] inhibited PKCK2 2.2-fold more efficiently than did TBB (IC₅₀ = 1.24 μM), which is quite specific toward PKCK2 with respect to ATP binding, in a panel of 31 human protein kinases. The K_i values of compound 24 and TBB for PKCK2 were 0.78 μM and 2.70 μM, respectively. Treatment of cells with compound 24 inhibited endogenous PKCK2 activity and showed anti-proliferative and pro-apoptotic effects against stomach and hepatocellular cancer cell lines more efficiently than did TBB. As expected, compound 24 also enabled tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-resistant cancer cells to be sensitive toward TRAIL. In comparing the molecular docking of compound 24 bound to PKCK2α versus previously reported complexes of PKCK2 with other inhibitors, our findings suggest a new scaffold for specific PKCK2α inhibitors. Thus, compound 24 appears to be a selective, cell-permeable, potent, and novel PKCK2 inhibitor worthy of further characterization.     

Effects of the methoxy group in the side chain of debromoaplysiatoxin on its tumor-promoting and anti-proliferative activities

Debromoaplysiatoxin (DAT) is a tumor promoter isolated from sea hare and exhibits anti-proliferative activity against several cancer cell lines. To clarify key residues that are responsible for its tumor-promoting activity, we focused on the chiral methoxy group in the side chain, whose role had not yet been discussed or examined before. Demethoxy-DAT (8) was derived from DAT and we evaluated its tumor-promoting activity, anti-proliferative activity, and ability to bind to protein kinase C (PKC) isozymes. Compound 8 showed somewhat weaker tumor-promoting activity than that of DAT both in vitro and in vivo, but showed higher anti-proliferative activity against several cancer cell lines. Although the affinity to novel PKC isozymes of 8 was comparable to that of DAT, the affinity to conventional PKC isozymes decreased slightly. These results suggest that the methoxy group of DAT is one of the key residues critical for tumor-promoting activity but not for anti-proliferative activity. Since the methoxy group has little influence on the molecular hydrophobicity, this is the first report showing that structural factors other than hydrophobicity in the side chain of DAT affected its biological activities.     

Design,synthesis and evaluation of novel indole derivatives as AKT inhibitors

Herein, we describe the discovery and synthesis of a new series of 1,2,4,7-tetra-substituted indole derivatives as novel AKT inhibitors by optimization of a weak hit methyl 4-(2-aminoethoxy)-1H-indole-2-carboxylate (1). Both representative compounds 6a and 6o exhibited the most potent inhibitory activities against AKT1, with inhibition rates of 72.5% and 78.6%, respectively, at concentrations of 10 nM. In addition, compounds 6a and 6o also potently inhibited the phosphorylation of the downstream GSK3 protein and displayed slightly better anti-proliferative activities in a prostate cancer cell line.