title: Effects of protein kinase C modulation by PEP005, a novel ingenol angelate, on mitogen-activated protein kinase and phosphatidylinositol 3-kinase signaling in cancer cells.
abstract: PEP005 (ingenol-3-angelate) is a novel anticancer agent extracted from Euphorbia peplus that was previously shown to modulate protein kinase C (PKC), resulting in antiproliferative and proapoptotic effects in several human cancer cell lines. In Colo205 colon cancer cells, exposure to PEP005 induced a time- and concentration-dependent decrease of cells in S phase of cell cycle and apoptosis. In Colo205 cells exposed to PEP005, a variety of signaling pathways were activated as shown by increased phosphorylation of PKCdelta, Raf1, extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase (MAPK), c-Jun NH(2)-terminal kinase, p38 MAPK, and PTEN. PEP005-induced activation of PKCdelta was associated with its translocation from the cytosol to the nucleus and other cellular membranes. Interestingly, PEP005 treatment also resulted in reduced expression of PKCalpha and reduced levels of phosphorylated active form of AKT/protein kinase B. These data suggest that PEP005-induced activation of PKCdelta and reduced expression of PKCalpha resulted in apoptosis by mechanisms mediated by activation of Ras/Raf/MAPK and inhibition of the phosphatidylinositol 3-kinase/AKT signaling pathways. This study supports ongoing efforts targeting PKC isoforms in cancer therapy with PEP005 alone and in combination with other cytotoxic agents.
authors.affiliation: Institut National de la Sante et de la Recherche Medicale-U728-RAYLAB and Department of Medical Oncology, Beaujon University Hospital, Clichy, France.
authors.forename: Maria
authors.initials: M
authors.lastname: Serova
authors.forename: Aïda
authors.initials: A
authors.lastname: Ghoul
authors.forename: Karim A
authors.initials: KA
authors.lastname: Benhadji
authors.forename: Sandrine
authors.initials: S
authors.lastname: Faivre
authors.forename: Christophe
authors.initials: C
authors.lastname: Le Tourneau
authors.forename: Esteban
authors.initials: E
authors.lastname: Cvitkovic
authors.forename: Francois
authors.initials: F
authors.lastname: Lokiec
authors.forename: Janet
authors.initials: J
authors.lastname: Lord
authors.forename: Steven M
authors.initials: SM
authors.lastname: Ogbourne
authors.forename: Fabien
authors.initials: F
authors.lastname: Calvo
authors.forename: Eric
authors.initials: E
authors.lastname: Raymond
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology; D004224:Diterpenes / Q000494:pharmacology*; D004952:Esters / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051571:Protein Kinase C-alpha / Q000378:metabolism*; D051745:Protein Kinase C-delta / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016196:S Phase / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: C486592:3-ingenyl angelate; D004224:Diterpenes; D004952:Esters; D012333:RNA, Messenger; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D019908:Proto-Oncogene Proteins c-raf; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human