piperidines and zileuton

Topics: Antioxidants; Arachidonate 5-Lipoxygenase; Catalytic Domain; Drug Design; Enzyme Assays; Humans; Hydroxyurea; Lipoxygenase Inhibitors; Molecular Docking Simulation; Molecular Structure; Peroxidases; Piperidines; Structure-Activity Relationship

Endocannabinoids have recently drawn attention as promising anti-cancer agents. We previously observed that anandamide (AEA), one of the representative endocannabinoids, effectively inhibited the proliferation of head and neck squamous cell carcinoma (HNSCC) cell lines in a receptor-independent manner. In this study, using HNSCC cell lines, we examined the anti-cancer effects and the mechanisms of action of docosahexaenoyl ethanolamide (DHEA) and N-arachidonoyl-L-alanine (NALA), which are polyunsaturated fatty acid (PUFA)-based ethanolamides like AEA.. DHEA and NALA were found to effectively inhibit HNSCC cell proliferation. These anti-proliferative effects seemed to be mediated in a cannabinoid receptor-independent manner, since the antagonist of cannabinoid receptor-1 (CB1) and vanilloid receptor-1 (VR1), two endocannabinoid receptors, did not reverse the ability of DHEA and NALA to induce cell death. Instead, we observed an increase in reactive oxygen species (ROS) production and a decrease of phosphorylated Akt as a result of DHEA and NALA treatment. Antioxidants efficiently reversed the inhibition of cell proliferation and the decrease of phosphorylated Akt induced by DHEA and NALA; inhibition of 5-lipoxygenase (5-LO), which is expected to be involved in DHEA- and NALA-degradation pathway, also partially blocked the ability of DHEA and NALA to inhibit cell proliferation and phosphorylated Akt. Interestingly, ROS production as a result of DHEA and NALA treatment was decreased by inhibition of 5-LO.. From these findings, we suggest that ROS production induced by the 5-LO pathway mediates the anti-cancer effects of DHEA and NALA on HNSCC cells. Finally, our findings suggest the possibility of a new cancer-specific therapeutic strategy, which utilizes 5-LO activity rather than inhibiting it.

Topics: Alanine; Antineoplastic Agents; Apoptosis; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Azoles; Benzoquinones; Carcinogenesis; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Endocannabinoids; Head and Neck Neoplasms; Humans; Hydroxyurea; Isoindoles; Lipoxygenase Inhibitors; Organoselenium Compounds; Phosphorylation; Piperidines; Proto-Oncogene Proteins c-akt; Pyrazoles; Reactive Oxygen Species; Receptor, Cannabinoid, CB1; Signal Transduction; Squamous Cell Carcinoma of Head and Neck; TRPV Cation Channels

Leukotriene A(4) hydrolase (LTA(4)H) catalyzes production of the proinflammatory lipid mediator, leukotriene (LT) B(4), which is implicated in a number of inflammatory diseases. We have identified a potent and selective inhibitor of both the epoxide hydrolase and aminopeptidase activities of recombinant human LTA(4)H (IC(50), approximately 10 nM). In a murine model of arachidonic acid-induced ear inflammation, the LTA(4)H inhibitor, JNJ-26993135 (1-[4-(benzothiazol-2-yloxy)-benzyl]-piperidine-4-carboxylic acid), dose-dependently inhibited ex vivo LTB(4) production in blood, in parallel with dose-dependent inhibition of neutrophil influx (ED(50), 1-3 mg/kg) and ear edema. In murine whole blood and in zymosan-induced peritonitis, JNJ-26993135 selectively inhibited LTB(4) production, without affecting cysteinyl leukotriene production, while maintaining or increasing production of the anti-inflammatory mediator, lipoxin (LX) A(4). The 5-lipoxygenase (5-LO) inhibitor zileuton showed inhibition of LTB(4), LTC(4), and LXA(4) production. Although zileuton inhibited LTB(4) production in the peritonitis model more effectively than the LTA(4)H inhibitor, the influx of neutrophils into the peritoneum after 1 and 2 h was significantly higher in zileuton- versus JNJ-26993135-treated animals. This difference may have been mediated by the increased LXA(4) levels in the presence of the LTA(4)H inhibitor. The selective inhibition of LTB(4) production by JNJ-26993135, while increasing levels of the anti-inflammatory mediator, LXA(4), may translate to superior therapeutic efficacy versus 5-LO or 5-LO-activating protein inhibitors in LTB(4)-mediated inflammatory diseases.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Ascitic Fluid; Benzothiazoles; Dogs; Ear; Edema; Eicosanoids; Enzyme Inhibitors; Epoxide Hydrolases; Female; Humans; Hydroxyurea; Inflammation; Leukotriene B4; Leukotriene C4; Lipoxins; Lipoxygenase Inhibitors; Mice; Mice, Inbred BALB C; Mice, Inbred Strains; Neutrophil Infiltration; Peritonitis; Piperidines; Recombinant Proteins