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Biochemical and Biophysical Research... Jul 1995The effect of wortmannin, which inhibits phosphatidylinositol 3-kinase (PI 3-kinase), on adipocytic differentiation of 3T3-L1 cells was examined. The extent of...
The effect of wortmannin, which inhibits phosphatidylinositol 3-kinase (PI 3-kinase), on adipocytic differentiation of 3T3-L1 cells was examined. The extent of differentiation was evaluated by the staining of adipocytes with Oil Red O and measurement of glycerol 3-phosphate dehydrogenase (GPDH) activity. Wortmannin, at over 100 nM, significantly inhibited adipogenesis of cells treated with isobutyl-methylxanthine, dexamethasone, and insulin with an IC50 value about 50 nM. These results suggest that PI 3-kinase plays a role in adipocytic differentiation of 3T3-L1 cells.
Topics: 1-Methyl-3-isobutylxanthine; 1-Phosphatidylinositol 4-Kinase; 3T3 Cells; Adipocytes; Androstadienes; Animals; Cell Differentiation; Dexamethasone; Dose-Response Relationship, Drug; Enzyme Inhibitors; Glyceraldehyde-3-Phosphate Dehydrogenases; Insulin; Mice; Phosphatidylinositol 3-Kinases; Phosphotransferases (Alcohol Group Acceptor); Wortmannin
PubMed: 7541986
DOI: 10.1006/bbrc.1995.1965 -
Biochemical and Biophysical Research... Apr 2000To determine the role of phosphatidylinositol 3-kinase (PI3-kinase) in the regulation of insulin secretion, we examined the effect of wortmannin, a PI3-kinase inhibitor,...
To determine the role of phosphatidylinositol 3-kinase (PI3-kinase) in the regulation of insulin secretion, we examined the effect of wortmannin, a PI3-kinase inhibitor, on insulin secretion using the isolated perfused rat pancreas and freshly isolated islets. In the perfused pancreas, 10(-8) M wortmannin significantly enhanced the insulin secretion induced by the combination of 8.3 mM glucose and 10(-5) M forskolin. In isolated islets, cyclic AMP (cAMP) content was significantly increased by wortmannin in the presence of 3.3 mM, 8.3 mM, and 16.7 mM glucose with or without forskolin. In the presence of 16.7 mM glucose with or without forskolin, wortmannin promoted insulin secretion significantly. On the other hand, in the presence of 8.3 mM glucose with forskolin, wortmannin augmented insulin secretion significantly; although wortmannin tended to promote insulin secretion in the presence of glucose alone, it was not significant. To determine if wortmannin increases cAMP content by promoting cAMP production or by inhibiting cAMP reduction, we examined the effects of wortmannin on 10(-4) M 3-isobutyl-1-methylxantine (IBMX)-induced insulin secretion and cAMP content. In contrast to the effect on forskolin-induced secretion, wortmannin had no effect on IBMX-induced insulin secretion or cAMP content. Moreover, wortmannin had no effect on nonhydrolyzable cAMP analog-induced insulin secretion in the perfusion study. These data indicate that wortmannin induces insulin secretion by inhibiting phosphodiesterase to increase cAMP content, and suggest that PI3-kinase inhibits insulin secretion by activating phosphodiesterase to reduce cAMP content.
Topics: 1-Methyl-3-isobutylxanthine; Androstadienes; Animals; Colforsin; Cyclic AMP; Enzyme Inhibitors; Glucose; In Vitro Techniques; Insulin; Insulin Secretion; Islets of Langerhans; Kinetics; Male; Perfusion; Phosphoinositide-3 Kinase Inhibitors; Rats; Rats, Wistar; Signal Transduction; Wortmannin
PubMed: 10772905
DOI: 10.1006/bbrc.2000.2514 -
Bioconjugate Chemistry Nov 2009Double drugs are obtained when two pharmacologically active entities are covalently joined to improve potency. We conjugated the viridin Wm with a self-activating...
Double drugs are obtained when two pharmacologically active entities are covalently joined to improve potency. We conjugated the viridin Wm with a self-activating linkage to cetuximab and demonstrated the retention of immunoreactivity by the conjugate. Though cetuximab lacked a growth inhibitory activity against A549 cells, the Wm-cetuximab conjugate had an antiproliferative IC(50) of 155 nM in vitro. The chemistry of attaching a self-releasing Wm to clinically approved antibodies is general and, in selected instances, may yield antibody-based double drugs with improved efficacy.
Topics: Androstadienes; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Cetuximab; Cross-Linking Reagents; Drug Design; Drug Synergism; Humans; Immunoconjugates; Immunosuppressive Agents; Inhibitory Concentration 50; Wortmannin
PubMed: 19883074
DOI: 10.1021/bc900176a -
Molecular Cancer Therapeutics Jul 2019Targeting of extrinsic apoptosis pathway by TNF-related apoptosis-inducing ligand (TRAIL) is an attractive approach for cancer therapy. However, two TRAIL drug...
Targeting of extrinsic apoptosis pathway by TNF-related apoptosis-inducing ligand (TRAIL) is an attractive approach for cancer therapy. However, two TRAIL drug candidates failed in clinical trials due to lack of efficacy. We identified 17-hydroxy wortmannin (17-HW) in a drug repurposing screen that resensitized TRAIL's response in the resistant colon cancer cells. The deficiency of caspase-8 in drug-resistant cells along with defects in apoptotic cell death was corrected by 17-HW, an inhibitor of PIK3C3-beclin 1 (BECN1) complex and autophagy activity. Further study found that BECN1 significantly increased in the TRAIL-resistant cells, resulting in increased autophagosome formation and enhanced autophagy flux. The extracellular domain (ECD) of BECN1 directly bound to the caspase-8 catalytic subunit (p10), leading to sequestration of caspase-8 in the autophagosome and its subsequent degradation. Inhibition of BECN1 restored the caspase-8 level and TRAIL's apoptotic response in the resistant colon cancer cells. An analysis of 120 colon cancer patient tissues revealed a correlation of a subgroup of patients (30.8%, 37/120) who have high BECN1 level and low caspase-8 level with a poor survival rate. Our study demonstrates that the increased BECN1 accompanied by enhanced autophagy activity is responsible for the TRAIL resistance, and a combination of TRAIL with a PIK3C3-BECN1 inhibitor is a promising therapeutic approach for the treatment of colon cancer.
Topics: Autophagy; Beclin-1; Cell Line, Tumor; Colonic Neoplasms; Humans; TNF-Related Apoptosis-Inducing Ligand; Transfection; Wortmannin
PubMed: 31092562
DOI: 10.1158/1535-7163.MCT-18-1241 -
The American Journal of Physiology May 1996Wortmannin, an inhibitor of myosin light-chain kinase (10-30 microM), completely and irreversibly abolished (in 75% of tissues from canine gastric antrum) phase...
Wortmannin, an inhibitor of myosin light-chain kinase (10-30 microM), completely and irreversibly abolished (in 75% of tissues from canine gastric antrum) phase contractions caused by slow waves with no significant effects on resting membrane potential or the frequency, amplitude, or duration of spontaneous slow waves. Responses to agents that normally cause hyperpolarization (cromakalim, sodium nitroprusside, and forskolin) were unaffected by wortmannin treatment. It was also possible to study the excitatory effects of agents and conditions that normally result in loss of intracellular impalements: 1) elevated extracellular K+ concentrations altered membrane potential close to values predicted by the Nernst equation, and 2) high concentrations of acetylcholine produced depolarization and rapid oscillations in membrane potential coincident with contractile activity. Cholinergic increases in myosin light-chain phosphorylation and contractions were partially blocked by wortmannin. In canine antrum, wortmannin inhibition of contraction was irreversible, although in other tissue types, partial recovery of contractions was observed when wortmannin was removed. Wortmannin can be a useful agent to investigate the electrophysiology of some smooth muscles when movement might lead to recording artifacts or loss of signal.
Topics: Androstadienes; Animals; Dogs; Electrophysiology; Female; Gastrointestinal Motility; Male; Muscle, Smooth; Myosin-Light-Chain Kinase; Stomach; Wortmannin
PubMed: 8967441
DOI: 10.1152/ajpcell.1996.270.5.C1405 -
Molecules (Basel, Switzerland) Jul 2018Wortmannin is a potent covalent inhibitor of PI3K that shows substantial in vivo toxicity and thus is unsuitable for systemic therapeutic applications. One possible...
Wortmannin is a potent covalent inhibitor of PI3K that shows substantial in vivo toxicity and thus is unsuitable for systemic therapeutic applications. One possible approach to minimize systemic toxicity is to generate a latent wortmannin pro-drug that will be selectively activated in target tissues. To test this approach, a wortmannin derivative with a leucine linker attached to C20 has been synthesized and tested for inhibition of PI3K activity in prostate cancer cells. Analysis of PI3K pathway inhibition by Wormannin-Leu (Wn-L) and intact Wortmannin (Wn) showed that attachment of Leu at C-20 decreased potency of PI3K pathway inhibition 10-fold compared to intact wortmannin, yet exceeded the potency of a competitive PI3K inhibitor LY294002.
Topics: Androstadienes; Calorimetry, Differential Scanning; Enzyme Inhibitors; Humans; Magnetic Resonance Spectroscopy; Molecular Structure; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Wortmannin
PubMed: 30036994
DOI: 10.3390/molecules23071791 -
Cancer Research May 1994Phosphatidylinositol-3-kinase is an important enzyme for intracellular signaling. The microbial product wortmannin and some of its analogues have been shown to be potent...
Phosphatidylinositol-3-kinase is an important enzyme for intracellular signaling. The microbial product wortmannin and some of its analogues have been shown to be potent inhibitors of phosphatidylinositol-3-kinase. The 50% inhibitory concentration for inhibition by wortmannin is 2 to 4 nM. Kinetic analysis demonstrates that wortmannin is a noncompetitive, irreversible inhibitor of phosphatidylinositol-3-kinase, with inactivation being both time- and concentration-dependent. Wortmannin has previously been reported to be an inhibitor of myosin light chain kinase but with an inhibitory concentration of 0.2 microM. Wortmannin was found not to be an inhibitor of phosphatidylinositol-4-kinase, protein kinase C, or protein tyrosine kinase. Wortmannin inhibited the formation of phosphatidylinositol-3-phosphates in intact cells. The results of the study suggest that wortmannin and its analogues may have utility as pharmacological probes for studying the actions of phosphatidylinositol-3-kinase.
Topics: 3T3 Cells; Androstadienes; Animals; Mice; Phosphatidylinositol 3-Kinases; Phosphotransferases (Alcohol Group Acceptor); Wortmannin
PubMed: 8162590
DOI: No ID Found -
Cell Reports Dec 2023Selective autophagy mediates the removal of harmful material from the cytoplasm. This cargo material is selected by cargo receptors, which orchestrate its sequestration...
Selective autophagy mediates the removal of harmful material from the cytoplasm. This cargo material is selected by cargo receptors, which orchestrate its sequestration within double-membrane autophagosomes and subsequent lysosomal degradation. The cargo receptor p62/SQSTM1 is present in cytoplasmic condensates, and a fraction of them are constantly delivered into lysosomes. However, the molecular composition of the p62 condensates is incompletely understood. To obtain insights into their composition, we develop a method to isolate these condensates and find that p62 condensates are enriched in components of the translation machinery. Furthermore, p62 interacts with translation initiation factors, and eukaryotic initiation factor 2α (eIF2α) and eIF4E are degraded by autophagy in a p62-dependent manner. Thus, p62-mediated autophagy may in part be linked to down-regulation of translation initiation. The p62 condensate isolation protocol developed here may facilitate the study of their contribution to cellular quality control and their roles in health and disease.
Topics: Humans; HEK293 Cells; RNA-Binding Proteins; Biomolecular Condensates; Eukaryotic Initiation Factor-2; Eukaryotic Initiation Factor-4E; Autophagy; Wortmannin
PubMed: 38096057
DOI: 10.1016/j.celrep.2023.113583 -
Angewandte Chemie (International Ed. in... Dec 2002
Topics: Androstadienes; Enzyme Inhibitors; Molecular Structure; Wortmannin
PubMed: 12481324
DOI: 10.1002/anie.200290014 -
International Immunology Nov 1997Peptide-class II complexes are assembled in endocytic, lysosome-like compartments where newly synthesized class II molecules are targeted from the trans-Golgi network...
Peptide-class II complexes are assembled in endocytic, lysosome-like compartments where newly synthesized class II molecules are targeted from the trans-Golgi network (TGN). Recent studies have implicated phosphatidylinositol 3-kinase (PI3-kinase) as an essential component in membrane trafficking from the TGN to lysosomes. Here, using subcellular fractionation, we show PI3-kinase activity associated with subcellular fractions which contain the class II peptide-loading compartment (IIPLC) in B cells. At concentrations required for inhibition of PI3-kinase activity in vivo, wortmannin blocked the processing and presentation of antigen by B cells to T cells. Treatment of B cells with wortmannin significantly limited the proteolytic degradation of invariant chain and the formation of peptide-class II complexes. Subcellular fractionation coupled with pulse-chase analyses showed that invariant chain and class II molecules trafficked to the IIPLC in wortmannin-treated cells. However, wortmannin prevented the maturation and correct targeting to the IIPLC of cathepsin D, a protease necessary for the degradation of invariant chain and assembly of processed antigen-class II complexes. These results suggest that li-class II complexes traffic to the IIPLC via a pathway that is relatively insensitive to wortmannin, but suggest a role for PI3-kinases in the trafficking of other components necessary for the assembly of processed antigen class II complexes to the IIPLC.
Topics: Androstadienes; Animals; Antigen Presentation; Cathepsin D; Cells, Cultured; Columbidae; Enzyme Inhibitors; Histocompatibility Antigens Class II; Humans; Mice; Phosphoinositide-3 Kinase Inhibitors; Subcellular Fractions; Wortmannin
PubMed: 9418132
DOI: 10.1093/intimm/9.11.1709