Development of novel synthesized phthalazinone-based PARP-1 inhibitors with apoptosis inducing mechanism in lung cancer

Herein we report the synthesis of two series of 4-phenylphthalazin-1-ones 11a-i and 4- benzylphthalazin-1-ones 16a-h as anti-lung adenocarcinoma agents with potential inhibitory activity against PARP-1. All the newly synthesized phthalazinones were evaluated for their anti-proliferative activity against A549 lung carcinoma cell line. Phthalazinones 11c-i and 16b, c showed significant cytotoxic activity against A549 cells at different concentrations (0.1, 1 and 10 μM) for two time intervals (24 h and 48 h). These nine phthalazinones were further examined for their inhibitory activity towards PARP-1. Compound 11c emerged as the most potent PARP-1 inhibitor with IC₅₀ value of 97 nM, compared to that of Olaparib (IC₅₀ = 139 nM). Furthermore, all these nine phthalazinones passed the filters of Lipinski and Veber rules, and predicted to have good pharmacokinetics properties in a theoretical kinetic study. On the other hand, western blotting in A549 cells revealed the enhanced expression of the cleaved PARP-1, alongside, with the reduced expression of pro-caspase-3 and phosphorylated AKT. In addition, ELISA assay confirmed the up-regulation of active caspase-3 and caspase-9 levels compared to the control, suggesting the activation of the apoptotic machinery in the A549 cells. Finally, molecular docking of 11c into PARP-1 active site (PDB: 5WRZ) was performed to explore the probable binding mode.     

Novel tricyclic poly (ADP-ribose) polymerase-1/2 inhibitors with potent anticancer chemopotentiating activity: Design,synthesis and biological evaluation

8,9-Dihydro-2,4,7,9a-tetraazabenzo[cd]azulen-6(7H)-ones were designed and synthesized as a new class of PARP-1/2 inhibitors. The compounds displayed a variable pattern of PARP-1/2 enzymes inhibition profile that, in part, paralleled the antiproliferative activity in cell lines. Among them, compound 9e exhibited not only the significant IC₅₀ value of 28 nM in the PARP-1 and 7.7 nM in PARP-2 enzyme assay, but also a profound synergic efficacy combined with temozolomide with PF₅₀ values of 2.6, 2.5, and 6.5 against MDA-MB-468, SW-620 and A549 and cell line, respectively.     

Design,synthesis, in vitro and in vivo evaluation,and structure-activity relationship (SAR) discussion of novel dipeptidyl boronic acid proteasome inhibitors as orally available anti-cancer agents for the treatment of multiple myeloma and mechanism studies

A series of novel dipeptidyl boronic acid inhibitors of 20S proteasome were designed and synthesized. Aliphatic groups at R¹ position were designed for the first time to fully understand the SAR (structure–activity relationship). Among the screened compounds, novel inhibitor 5c inhibited the CT-L (chymotrypsin-like) activity with IC₅₀ of 8.21?nM and the MM (multiple myeloma) cells RPMI8226, U266B and ARH77 proliferations with the IC₅₀ of 8.99, 6.75 and 9.10?nM, respectively, which showed similar in vitro activities compared with the compound MLN2238 (biologically active form of marketed MLN9708). To investigate the oral availability, compound 5c was esterified to its prodrug 6a with the enzymatic IC₅₀ of 6.74?nM and RPMI8226, U266B and ARH77 cell proliferations IC₅₀ of 2.59, 4.32 and 3.68?nM, respectively. Furthermore, prodrug 6a exhibited good pharmacokinetic properties with oral bioavailability of 24.9%, similar with MLN9708 (27.8%). Moreover, compound 6a showed good microsomal stabilities and displayed stronger in vivo anticancer efficacy than MLN9708 in the human ARH77 xenograft mouse model. Finally, cell cycle results showed that compound 6a had a significant inhibitory effect on CT-L and inhibited cell cycle progression at the G2M stage.     

Design and synthesis of novel dasatinib derivatives as inhibitors of leukemia stem cells

We used the concept of bioisosteres to design and synthesize a novel series of dasatinib derivatives for the treatment of leukemia. Unfortunately, most of the dasatinib derivatives did not show appreciable inhibition against leukemia cell lines K562 and HL60. However, acrylamide compound 2c had comparable inhibitory activity with dasatinib against K562 cells (IC₅₀?=?0.039?nM vs. 0.069?nM). And amide compound 2a and acrylamide compound 2c also had comparable inhibitory activity with dasatinib against the leukemia cell line HL60 (IC₅₀?=?0.25?nM and 0.26?nM vs. 0.11?nM). Against the leukemia progenitor cell line KG1a, triazole compounds 15a and 15d–15f and oxadiazole compounds 24a–24d were more potent than dasatinib. In particular, the hydroxyl compounds 15a and 24a were about 64 and 180 fold more potent than dasatinib against KG1a cells (IC₅₀?=?0.14?μM and 0.05?μM vs. 8.98?μM). Compounds 15a and 24a also inhibited colony formation in MCF-7 cells and inhibited cell migration in the cell wound scratch assay in B16BL6 cells. Moreover, hydroxyl compounds 15a and 24a had low toxicity in vivo.     

Design,synthesis and biological evaluation of 2,5-dimethylfuran-3-carboxylic acid derivatives as potential IDO1 inhibitors

Indoleamine 2,3-dioxygenase 1 (IDO1) plays a vital role in tumor immune escape and has emerged as a promising target for cancer immunotherapy. In this study, a novel series of 2,5-dimethylfuran-3-carboxylic acid derivatives were designed, synthesized and evaluated for inhibitory activities against IDO1, and their structure-activity relationship was investigated. Among these, compound 19a exhibited excellent IDO1 inhibitory activity (HeLa cellular IC₅₀?=?4.0?nM, THP-1 cellular IC₅₀?=?4.6?nM). Further molecular docking studies revealed that the compound 19a formed a coordinate bond with the heme iron through the carboxylic acid moiety. These results indicate that compound 19a is a potential IDO1 inhibitor for further investigation.     

Structure-based design and synthesis of 1H-pyrazolo[3,4-d]pyrimidin-4-amino derivatives as Janus kinase 3 inhibitors

Janus kinases (JAKs) regulate various inflammatory and immune responses and are targets for the treatment of inflammatory and immune diseases. Here we report the discovery and optimization of 1H-pyrazolo[3,4-d]pyrimidin-4-amino as covalent JAK3 inhibitors that exploit a unique cysteine (Cys909) residue in JAK3. Our optimization study gave compound 12a, which exhibited potent JAK3 inhibitory activity (IC₅₀ of 6.2?nM) as well as excellent JAK kinase selectivity (>60-fold). In cellular assay, 12a exhibited potent immunomodulating effect on IL-2-stimulated T cell proliferation (IC₅₀ of 9.4?μM). Further, compound 12a showed efficacy in delayed hypersensitivity assay. The data supports the further investigation of these compounds as novel JAKs inhibitors.     

Design,synthesis and biological evaluation of thienopyridinones as Chk1 inhibitors

A series of thienopyridinone derivatives was designed and synthesized as inhibitors of checkpoint kinase 1 (Chk1). Most of them exhibited moderate to good Chk1 inhibitory activities. Among them, compounds 8q, 8t, and 8w with excellent Chk1 inhibitory activities (IC₅₀ values of 4.05, 6.23, and 2.33 nM, respectively) displayed strong synergistic effects with melphalan, a DNA-damaging agent in the cell-based assay. Further kinase profiling indicated that compound 8t was highly selective against CDK2/cyclinA, Aurora A, and PKC.     

Design,synthesis and evaluation of vilazodone-tacrine hybrids as multitarget-directed ligands against depression with cognitive impairment

Depression, a severe mental disease, is greatly difficult to treat and easy to induce other neuropsychiatric symptoms, the most frequent one is cognitive impairment. In this study, a series of novel vilazodone-tacrine hybrids were designed, synthesized and evaluated as multitarget agents against depression with cognitive impairment. Most compounds exhibited good multitarget activities and appropriate blood-brain barrier permeability. Specifically, compounds 1d and 2a exhibited excellent 5-HT_1A agonist activities (1d, EC₅₀?=?0.36?±?0.08?nM; 2a, EC₅₀?=?0.58?±?0.14?nM) and 5-HT reuptake inhibitory activities (1d, IC₅₀?=?20.42?±?6.60?nM; 2a, IC₅₀?=?22.10?±?5.80?nM). In addition, they showed moderate ChE inhibitory activities (1d, AChE IC₅₀?=?1.72?±?0.217?μM, BuChE IC₅₀?=?0.34?±?0.03?μM; 2a, AChE IC₅₀?=?2.36?±?0.34?μM, BuChE IC₅₀?=?0.10?±?0.01?μM). Good multitarget activities with goodt blood-brain barrier permeability of 1d and 2a make them good lead compounds for the further study of depression with cognitive impairment.     

Design,synthesis and biological evaluation of novel 4,5-dihydro-[1,2,4]triazolo[4,3-f]pteridine derivatives as potential BRD4 inhibitors

Recently, diverse kinase inhibitors were reported having interaction with BRD4. It provided a strategy for developing a new structural framework for the next-generation BRD4-selective inhibitors. Starting from PLK1 kinase inhibitor BI-2536, we designed 18 compounds by modifying dihydropteridine core. Compound 23 showed potent BRD4 inhibitory activities with IC₅₀ of 79 nM and no inhibitory activities for PLK1. Cell antiproliferation assay was performed and potent inhibitory activity against MV4;11 with IC₅₀ of 1.53 μM. Cell apoptosis and western blotting indicated compound 23 induced apoptosis by down-regulating c-Myc. These novel selective BRD4 inhibitors provided new lead compounds for further drug development.     

Identification of a novel boronic acid as a potent,selective, and orally active hormone sensitive lipase inhibitor

Hormone sensitive lipase (HSL) is an attractive therapeutic target of dyslipidemia. We designed and synthesized several compounds as reversible HSL inhibitors with a focus on hydrophobic interactions, which was thought to be effective upon the HSL inhibitory activity. In these efforts, we identified boronated compound 12 showing a potent HSL inhibitory activity with an IC₅₀ value of 7 nM and a high selectivity against cholinesterases. Furthermore, compound 12 is the first boron containing HSL inhibitor that has shown an antilipolytic effect in rats after oral administration at 3 mg/kg.     

Novel tacrine-coumarin hybrids linked to 1,2,3-triazole as anti-Alzheimer’s compounds: In vitro and in vivo biological evaluation and docking study

A new series of tacrine-coumarin hybrids linked to 1,2,3-triazole were designed, synthesized, and tested as potent dual binding site cholinesterase inhibitors (ChEIs) for the treatment of Alzheimer’s disease (AD). Among them, compound 8e was the most potent anti-AChE derivative (IC₅₀ = 27 nM) and compound 8m displayed the best anti-BChE activity (IC₅₀ = 6 nM) much more active than tacrine and donepezil as the reference drugs. Compound 8e was also evaluated for its BACE1 inhibitory activity and neuroprotectivity against PC12 cells exposed to Aβ_25-35 which indicated low activity. Finally, in vivo studies by Morris water maze task showed that compound 8e significantly reversed scopolamine-induced memory deficit in rats.     

Design,synthesis and evaluation of phthalide alkyl tertiary amine derivatives as promising acetylcholinesterase inhibitors with high potency and selectivity against Alzheimer's disease

A series of phthalide alkyl tertiary amine derivatives were designed, synthesized and evaluated as potential multi-target agents against Alzheimer’s disease (AD). The results indicated that almost all the compounds displayed significant AChE inhibitory and selective activities. Besides, most of the derivatives exhibited increased self-induced Aβ_1-42 aggregation inhibitory activity compared to the lead compound dl-NBP, and some compounds also exerted good antioxidant activity. Specifically, compound I-8 showed the highest inhibitory potency toward AChE (IC₅₀ = 2.66 nM), which was significantly better than Donepezil (IC₅₀ = 26.4 nM). Moreover, molecular docking studies revealed that compound I-8 could bind to both the catalytic active site and peripheral anionic site of AChE. Furthermore, compound I-8 displayed excellent BBB permeability in vitro. Importantly, the step-down passive avoidance test indicated that I-8 significantly reversed scopolamine-induced memory deficit in mice. Collectively, these results suggested that I-8 might be a potent and selective AChE inhibitor for further anti-AD drug development.     

A new series of aryl sulfamate derivatives: Design,synthesis, and biological evaluation

Steroid sulfatase (STS) has recently emerged as a drug target for management of hormone-dependent malignancies. In the present study, a new series of twenty-one aryl amido-linked sulfamate derivatives 1a-u was designed and synthesized, based upon a cyclohexyl lead compound. All members were evaluated as STS inhibitors in a cell-free assay. Adamantyl derivatives 1h and 1p-r were the most active with more than 90% inhibition at 10 µM concentration and, for those with the greatest inhibitory activity, IC₅₀ values were determined. These compounds exhibited STS inhibition within the range of ca 25–110 nM. Amongst them, compound 1q possessing a o-chlorobenzene sulfamate moiety exhibited the most potent STS inhibitory activity with an IC₅₀ of 26 nM. Furthermore, to assure capability to pass through the cell lipid bilayer, compounds with low IC₅₀ values were tested against STS activity in JEG-3 whole-cell assays. Consequently, 1h and 1q demonstrated IC₅₀ values of ca 14 and 150 nM, respectively. Thus, compound 1h is 31 times more potent than the corresponding cyclohexyl lead (IC₅₀ value = 421 nM in a JEG-3 whole-cell assay). Furthermore, the most potent STS inhibitors (1h and 1p-r) were evaluated for their antiproliferative activity against the estrogen-dependent breast cancer cell line T-47D. They showed promising activity with single digit micromolar IC₅₀ values (ca 1–6 µM) and their potency against T-47D cells was comparable to that against STS enzyme. In conclusion, this new class of adamantyl-containing aryl sulfamate inhibitor has potential for further development against hormone-dependent tumours.     

Structure-based optimization and biological evaluation of trisubstituted pyrazole as a core structure of potent ROS1 kinase inhibitors

Recently inhibition of ROS1 kinase has proven to be a promising strategy for several indications such as glioblastoma, non-small cell lung cancer (NSCLC), and cholangiocarcinoma. Our team reported trisubstituted pyrazole-based ROS1 inhibitors by which two inhibitors showed good IC₅₀ values in enzyme-based screening. To develop more advanced ROS1 inhibitors through SAR this trisubstituted pyrazole-based scaffold has been built. Consequently, 16 compounds have been designed, synthesized and shown potent IC₅₀ values in the enzymatic assay, which are from 13.6 to 283 nM. Molecular modeling studies explain how these ROS1 kinase inhibitors revealed effectively the key interactions with ROS1 ATP binding site. Among these compounds, compound 9a (IC₅₀ = 13.6 nM) has exerted 5 fold potency than crizotinib and exhibited high degree of selectivity (selectivity score value = 0.028) representing the number of non-mutant kinases with biological activity over 90% at 10 μM.     

Design,synthesis and anticancer evaluation of acridine hydroxamic acid derivatives as dual Topo and HDAC inhibitors

Multitarget inhibitors design has generated great interest in cancer treatment. Based on the synergistic effects of topoisomerase and histone deacetylase inhibitors, we designed and synthesized a new series of acridine hydroxamic acid derivatives as potential novel dual Topo and HDAC inhibitors. MTT assays indicated that all the hybrid compounds displayed good antiproliferative activities with IC₅₀ values in low micromolar range, among which compound 8c displayed potent activity against U937 (IC₅₀?=?0.90?μM). In addition, compound 8c also displayed the best HDAC inhibitory activity, which was several times more potent than HDAC inhibitor SAHA. Subsequent studies indicated that all the compounds displayed Topo II inhibition activity at 50?μM. Moreover, compound 8c could interact with DNA and induce U937 apoptosis. This study provides a suite of compounds for further exploration of dual Topo and HDAC inhibitors, and compound 8c can be a new dual Topo and HDAC inhibitory anticancer agent.     

Surrogating and redirection of pyrazolo[1,5-a]pyrimidin-7(4H)-one core,a novel class of potent and selective DPP-4 inhibitors

The initial focus on characterizing novel pyrazolo[1,5-a]pyrimidin-7(4H)-one derivatives as DPP-4 inhibitors, led to a potent and selective inhibitor compound b2. This ligand exhibits potent in vitro DPP-4 inhibitory activity (IC₅₀: 80?nM), while maintaining other key cellular parameters such as high selectivity, low cytotoxicity and good cell viability. Subsequent optimization of b2 based on docking analysis and structure-based drug design knowledge resulted in d1. Compound d1 has nearly 2-fold increase of inhibitory activity (IC₅₀: 49?nM) and over 1000-fold selectivity against DPP-8 and DPP-9. Further in vivo IPGTT assays showed that compound b2 effectively reduce glucose excursion by 34% at the dose of 10?mg/kg in diabetic mice. Herein we report the optimization and design of a potent and highly selective series of pyrazolo[1,5-a]pyrimidin-7(4H)-one DPP-4 inhibitors.     

Synthesis and biological evaluation of some novel thiobenzimidazole derivatives as anti-renal cancer agents through inhibition of c-MET kinase

Benzimidazole is an interesting scaffold constituting a main core in many anticancer agents against variable cell lines as Carbendazim (I) and Nocodazole (II). Accordingly, eighteen compounds of 2-((1H-benzoimidazol-2-yl)thio)-1-(aryl/heteroaryl)ethan-1-ones, in their sulfate salt and free forms, were designed and investigated as anticancer agents. In vitro preliminary screening of selected compounds by the National Cancer Institute (NCI) on a panel of 60 cell lines revealed renal cancer cell line (A498) as the most vulnerable cell line; accordingly, IC₅₀ values against A498 cell line were determined for compounds with the best results. The best inhibitory activity was for compound 4a with (IC₅₀ = 6.97 µM) compared to sunitinib as a reference drug (IC₅₀ = 6.99 µM). Compound 4a was further subjected to cell cycle analysis that indicated the decrease in cell population in the G2/M phase when compared to the untreated control cells. In addition, it showed significant increase in the late apoptosis in Annexin-V FTIC study compared to the control cells. An enzymatic inhibitory study on compound 4a against c-Met and MAP kinases revealed its better activity against c-Met kinase with (IC₅₀ = 0.27 µM) compared to sunitinib (IC₅₀ = 0.18 µM). Molecular docking study was conducted to reveal the interactions of compound 4a in the active site of c-Met kinase. Computational ADME study was performed to insure that compound 4a has proper pharmacokinetic and drug-likeness properties.     

Design,synthesis and biological evaluation of HIV-1 protease inhibitors with morpholine derivatives as P2 ligands in combination with cyclopropyl as P1′ ligand

A series of novel HIV-1 protease inhibitors has been designed and synthesized, which contained morpholine derivatives as the P2 ligands and hydrophobic cyclopropyl as the P1′ ligand at the meantime in this study, with the aim of improving the interactions between the active sites of HIV-1 protease and the inhibitors. Twenty-eight compounds were synthesized and assessed, among which inhibitors m18 and m1 exhibited excellent inhibitory effect on the activity of HIV-1 protease with IC₅₀ value of 47 nM and 53 nM, respectively. The molecular modeling of m1 revealed possible hydrogen bondings or van der Waals between the inhibitor and the protease, worthy of in-depth study.     

1,2,4-Trisubstituted imidazolinones with dual carbonic anhydrase and p38 mitogen-activated protein kinase inhibitory activity

Various 1,2,4 trisubstituted imidazolin-5-one derivatives were synthesized and evaluated for their inhibitory activity against p38 mitogen-activated protein kinase (p38MAPK) and carbonic anhydrase (CA) enzymes aiming to explore potential dual inhibitors. Results revealed that compounds 3c, 3g, 3h, 4a, 6c and 6d were the most effective derivatives against p38αMAPK (IC₅₀ = 0.14, 0.14, 0.056, 0.14, 0.13 and 0.14 μM, respectively) compared to sorafenib (IC₅₀ = 1.58 μM) as standard drug. On the other hand, compound 4a revealed the best inhibitory activity against all the tested carbonic anhydrase isoforms CA I, II, IV and IX with K_i values of 95.0, 0.83, 6.90 and 12.4 nM, respectively compared to acetazolamide with K_i values 250, 12.1, 74 and 12.8 nM, respectively. Therefore, compound 4a can be considered as a potent dual p38αMAPK/CA inhibitor.     

Discovery of 4-functionalized phenyl-O-β-d-glycosides as a new class of mushroom tyrosinase inhibitors

A series of 4-functionalized phenyl-O-β-d-glycosides were designed, synthesized and evaluated as a new class of mushroom tyrosinase inhibitors. The results demonstrated that compounds 6a–13a bearing a thiosemicarbazide moiety exhibited potent activities with IC₅₀ values range from 0.31 to 52.8 μM. Particularly, compound 9a containing acetylated glucose moiety was found to be the most active molecule with an IC₅₀ value of 0.31 μM. SARs analysis suggested that (1) the thiosemicarbazide moiety remarkably contributed to the increase of inhibitory effects on tyrosinase; (2) the configuration and bond type of sugar moiety also played a very important role in determining their inhibitory activities. The inhibition kinetics and inhibition mechanism study revealed that compound 9a was reversible and competitive type inhibitor, whereas compound 13a was reversible and competitive–uncompetitive mixed-II type inhibitor.