cholecalciferol and herbimycin

Support or inhibition of DAG-induced head formation: Hydra magnipapillata can be caused to form ectopic head structures by periodictreatmentwith PKC activators such as diacylglycerol (DAG). This ectopic head formation is supported by an extract from the ovine pineal gland that contains low-molecular-weight compounds. The frequency of ectopic head formation is also increased when DAG is paired with one of several lipophilic hormonal factors: (1) pinoline, a putative pineal hormone derived from tryptophan, (2) 12-S-HETE, a paracrine derivative of arachidonic acid, or (3) 1alpha, 25 dihydroxyvitamine D3, a hormonal factor also known as calcitriol. Dose-response curves were non-monotonic passing a maximum at low dosages. By contrast, DAG lost its capacity to induce ectopic head structures when it was paired with the provitamin D3, cholecalciferol. Patterning the head: one eicosanoid was found which influences patterning without being combined with DAG: 12-R-HETE caused growth-based elongation of the tentacles and an increase in the number of tentacles without affecting the longitudinal body pattern. Similar effects are brought about by substances that interfere with tyrosine phosphorylation, most potently bythe phosphotyrosine phosphatase inhibitor bisperoxo-(1,10-phenanthroline)-oxovanadate (V). The results speak for the existence of head-inducing hormonal factors, underline the significance of content protein kinases to pattern formation and point to a negative influence of the vitamin D3 content of the food on the capacity of the animals to develop head structures.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Benzoquinones; Calcitriol; Carbolines; Cell Extracts; Cholecalciferol; Diglycerides; Enzyme Activation; Enzyme Inhibitors; Head; Hormones; Hydra; Lactams, Macrocyclic; Molecular Weight; Pineal Gland; Protein Kinase C; Quinones; Rifabutin; src-Family Kinases; Vanadates

We showed previously that the expressions of various src family protein tyrosine kinases (PTKs) were induced independently during the monocytic differentiation of HL-60 cells. The role of PTKs was further assessed in the present study by investigating the effects of PTK inhibitors on the differentiation. It was demonstrated that PTK inhibitors such as genistein and herbimycin A modulated monocytic differentiation of HL-60 cells; they inhibited the differentiation induced by TPA, while promoting that induced by vitamin D3 (D3). Immunoblotting analysis of protein molecules which had been phosphorylated on their tyrosine residues demonstrated that TPA induced phosphorylation of certain molecules different from those induced by D3 in HL-60 cells. PTK inhibitors blocked the phosphorylation and modulated differentiation driven by the inducers. These data suggest that PTKs are involved both promotively and suppressively in signaling events that induce monocytic differentiation of HL-60 cells.

Topics: Antibiotics, Antineoplastic; Antibody-Dependent Cell Cytotoxicity; Benzoquinones; Cell Differentiation; Cholecalciferol; Genistein; Humans; Isoflavones; Lactams, Macrocyclic; Monocytes; Phosphorylation; Protein-Tyrosine Kinases; Quinones; Rifabutin; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured