benzofurans and Leukemia--Erythroblastic--Acute

New benzofuranhydrazones 3-12 were easily prepared and assayed for their radical-scavenging ability. Hydrazones 3-12 showed different extent antioxidant activity in DPPH, FRAP and ORAC assays. Good antioxidant activity is related to the number and position of hydroxyl groups on the arylidene moiety. High antioxidant activity is showed by the 2-hydroxy-4-(diethylamino)benzylidene derivative 11. Furthermore, hydrazones 3-12 showed photoprotective capacities with satisfactory in vitro SPF as compared to the commercial PBSA sunscreen filter. The antiproliferative effects of the hydrazones 3-12 was tested on erythroleukemia K562 and Colo-38 melanoma human cells. All the compounds showed growth inhibition in the micromolar to sub micromolar concentration range. If taken together these results points to benzofuran hydrazones as potential multifunctional molecules especially in the treatment of neoplastic diseases being the good antioxidant properties of 5, 7 and 11 correlated to their high antiproliferative activity.

Topics: Antineoplastic Agents; Antioxidants; Benzofurans; Cell Line, Tumor; Cell Proliferation; Drug Design; Humans; Hydrazones; Leukemia, Erythroblastic, Acute; Melanoma; Structure-Activity Relationship; Sunscreening Agents

The intracellular concentration of free Ca2+ was monitored by measuring the fluorescence of fura-2 loaded Human Erythroleukemia Cells. Neuropeptide Y (NPY) increased intracellular Ca2+ in a dose-dependent manner and the 50% effective concentration was 2 nM. Chelation of extracellular Ca2+ by EGTA did not reduce the NPY-mediated increase in cytoplasmic Ca2+, indicating that the increase in fluorescence was due to the release of intracellular Ca2+. A second dose of NPY, after intracellular Ca2+ had returned to basal levels, failed to elicit a response, indicating that the NPY receptor had undergone desensitization. In similar experiments, NPY increased the formation of inositol phosphates, suggesting that the mobilization of Ca2+ from intracellular stores in HEL cells was secondary to the generation of inositol phosphates and stimulation of phospholipase C.

Topics: Benzofurans; Calcium; Dose-Response Relationship, Drug; Egtazic Acid; Fluorescent Dyes; Fura-2; Humans; Inositol Phosphates; Kinetics; Leukemia, Erythroblastic, Acute; Neuropeptide Y; Spectrometry, Fluorescence; Tumor Cells, Cultured; Type C Phospholipases

Neuropeptide Y (NPY), a peptide often coreleased with catecholamines, appears to be an important component of the sympathetic nervous system, but little is known about the molecular basis of its action. We introduce here human erythroleukemia (HEL) cells as a new model system for studies of NPY action. NPY inhibited adenosine 3,5'-cyclic monophosphate (cAMP) accumulation in HEL cells with a 50% effective concentration (EC50) of 3 nM. Additionally NPY increased intracellular Ca2+, as assessed by fura-2 fluorescence, with a similar EC50. Pretreatment with pertussis toxin blocked both responses, suggesting the involvement of one or more G proteins. Chelating extracellular Ca2+ with EGTA did not reduce the Ca2+ signal, demonstrating mobilization from intracellular stores rather than influx. Experiments with various agents demonstrated that the Ca2+ mobilization was not secondary to lowering of cAMP levels, formation of arachidonic acid products, or Na+-H+ exchange. Ca2+ mobilization also did not appear to be associated with inositol phosphate generation. In conclusion, we demonstrate for the first time that NPY, in addition to inhibiting adenylate cyclase, also can elevate intracellular Ca2+. HEL cells should prove useful in further studies of the molecular basis of NPY action.

Topics: Adenylyl Cyclase Inhibitors; Benzofurans; Calcium; Cell Line; Fluorescent Dyes; Fura-2; Humans; Kinetics; Leukemia, Erythroblastic, Acute; Neuropeptide Y; Phosphatidylinositols