Discovery of novel NF-кB inhibitor based on scaffold hopping: 1,4,5,6,7,8-hexahydropyrido[4,3-d]pyrimidine.

NF-κB is a key signaling pathway molecule linking hepatoma and chronic inflammation. Inhibition of NF-κB activation can alleviate inflammation, and promote hepatoma cell apoptosis. In this study, a series of fluoro-substituted 1,4,5,6,7,8-hexahydropyrido[4,3-d]pyrimidines (PPMs, 31-57) were synthesized from 3,5-bis(arylidene)-4-piperidones (BAPs, 4-30) based on scaffold hopping. We successfully discovered the most potent 43 substituted by electron-withdrawing substitutes (3-F and 4-CF3) exhibited less toxicity and higher anti-inflammatory activity. Preliminary mechanistic studies revealed that 43 induced dose-dependent cell apoptosis at cell and protein level, while inhibited NF-κB activation by suppressing LPS-induced phosphorylation levels of p65, IκBα and Akt, and by indirectly suppressing MAPK signaling, and by inhibiting the nuclear translocation of NF-κB induced by TNF-α or LPS. Docking analysis verified simulated 43 could reasonably bind to the active site of Bcl-2, p65 and p38 proteins. This compound, as a novel NF-κB inhibitor, also demonstrated both anti-inflammatory and anti-hepatoma activities, warranting its further development as a potential multifunctional agent for the clinical treatment of liver cancers and inflammatory diseases.

Dissymmetric pyridyl-substituted 3,5-bis(arylidene)-4-piperidones as anti-hepatoma agents by inhibiting NF-κB pathway activation.

To get new anti-hepatoma agents with anti-inflammatory activity and hypotoxicity, a series of dissymmetric pyridyl-substituted 3,5-bis(arylidene)-4-piperidones (BAPs, 25-82) were designed and synthesized. Many of them exhibited potential anti-hepatoma properties against human hepatocellular carcinoma cell lines (HepG2, QGY-7703, SMMC-7721) and hypotoxicity for human normal heptical cell line (HHL-5, LO2), and prominently inhibited lipopolysaccharides (LPS) induced IL-6, TNF-α secretion to exert its anti-inflammatory effect. Combining the data of cytotoxicity, cytocompatibility and anti-inflammatory activity, 3-pyridyl and -CF3 substituted 67 may be the potential anti-hepatoma agent. 67 effectively promoted cell apoptosis through up-regulating cleaved caspase-3 and Bax expression and down-regulating Bcl-2 expression. Furthermore, 67 prominently inhibited NF-κB pathway activation by blocking the phosphorylation of IκBα, p65 and the nuclear translocation of NF-κB induced by TNF-α and LPS. In addition, 67 could reasonably bind to the active site of Bcl-2 and NF-κB/p65 protein proved by Molecular docking analyses. Moreover, 67 significantly suppressed the growth and inflammatory response of HepG2 xenografts in nude mice and was relatively nontoxic to mice. These results suggest that 67 may be effective and hypotoxicity anti-hepatoma agent for the clinical treatment of liver cancers.

N-phenylsulfonyl-3,5-bis(arylidene)-4-piperidone derivatives as activation NF-κB inhibitors in hepatic carcinoma cell lines.

Ten novel symmetric 3,5-bis(arylidene)-4-piperidone derivatives (BAPs, 1-10) and fourteen dissymmetric BAPs (11-24) were synthesized and evaluated the cytotoxicity. All of the compounds have been screened for their anti-inflammatory activity characterized by evaluating their inhibitory effects on LPS-induced IL-6, TNF-α secretion. Among them, BAP 23 exhibits both the highest anti-inflammatory and anti-cancer properties. Western blot analysis showed that BAP 23 markedly reduced the levels of Bcl-2 but increased the levels of cleaved caspase-3and Bax. Moreover, BAP 23 prominently inhibited LPS-induced activation of NF-κB in RAW264.7 cells as well as TNF-α-induced activation of NF-κB in HepG2 cells by blocking phosphorylation of inhibitor IκBα and p65. Consistent with these results, we found that BAP 23 prevented the nuclear translocation of NF-κB induced by LPS or TNF-α. BAP 23 could reasonably bind to the active site of Bcl-2 protein and p65 which is proved by molecular docking modes. These data indicate that BAP 23 is a more potent inhibitor of NF-κB activity which exhibites both anti-inflammatory and anticancer activities.

Novel dissymmetric 3,5-bis(arylidene)-4-piperidones as potential antitumor agents with biological evaluation in vitro and in vivo.

Thirty-five novel dissymmetric 3,5-bis(arylidene)-4-piperidone derivatives (BAPs, 6a-h, 7a-h, 8a-g, 9a-g, 10a-e) were synthesized and evaluated the cytotoxicity. BAPs 6d, 7h, 8g, 9g demonstrated the most potentially inhibitory activities against HepG2 and THP-1 but lower cytotoxicity toward LO2. In vitro, 6d, 7h, 8g, 9g can effectively up-regulate BAX expression, down-regulate Bcl-2 expression in HepG2 cell. They could reasonably bind to the active site of Bcl-2 protein proved by molecular docking modes. The most active BAP 6d induced HepG2 cells apoptosis in a dose-dependent manner by flow cytometrey. The cellular uptake of HepG2 cells showed 6d mainly accumulated into the nuclei by confocal laser scanning microscopy (CLSM). In vivo, 6d suppressed the growth of HepG2 xenografts in nude mice and relatively nontoxic to mice. These results suggest that 6d could be therapeutically beneficial as potential therapeutic agent for the early clinical treatment of liver cancers.

Quaternary ammonium salts substituted by 5-phenyl-1,3,4-oxadiazole-2-thiol as novel antibacterial agents with low cytotoxicity.

Twenty-one novel 5-phenyl-1,3,4-oxadiazole-2-thiol (POT) substituted N-hydroxyethyl quaternary ammonium salts (6a-g, 7a-g, 8a-g) were prepared and characterized by FTIR, NMR, and elemental analysis. Compounds 6a, 6c, and 8a were confirmed by X-ray single-crystal diffraction. They display the unsurpassed antibacterial activity against Staphylococcus aureus, α-H-tococcus, Escherichia coli, P. aeruginosa, Proteus vulgaris, Canidia Albicans, especially 6g, 7g, 8g with dodecyl group. Compounds 8a-d with N,N-dihydroxyethyl and POT groups display unsurpassed antibacterial activity and non-toxicity. The structure-activity relationships indicate that POT and flexible dihydroxyethyl group in QAS are necessary for antibacterial activity and cytotoxicity. SEM and TEM images of E. coli morphologies of 8d show the antibacterial agents can adhere to membrane surfaces to inhibit bacterial growth by disrupting peptidoglycan formation and releasing bacterial cytoplasm from cell membranes.