title: Plumbagin activates ERK1/2 and Akt via superoxide, Src and PI3-kinase in 3T3-L1 cells.
abstract: Plumbagin, derived from the plant Plumbago zeylanica, has been shown to chronically activate ERK1/2 and inhibit Akt activity in cancer cells. However, the acute effects of plumbagin on ERK1/2 and Akt activities remain unknown. In this study, we examined the effects of plumbagin on ERK1/2 and Akt activities in 3T3-L1 cells. Exposure of 3T3-L1 cells to plumbagin generated superoxide and activated both ERK1/2 and Akt. The plumbagin-stimulated ERK1/2 and Akt activities were sensitive to an antioxidant NAC, superoxide dismutase mimetic MnTBAP, superoxide scavenger Tiron and NAD(P)H oxidase inhibitor DPI. Plumbagin-stimulated ERK1/2 activity was attenuated by the MEK1/2 inhibitor PD98059 and Ras inhibitor manumycin A, whereas plumbagin-stimulated Akt activity was blocked by the PI3K inhibitor LY294002. Both plumbagin-stimulated ERK1/2 and Akt activities were attenuated by PP2, a Src inhibitor. Interestingly, inhibition of phosphatidylinositol 3-kinase (PI3-kinase), but not Akt, activity leaded to attenuation of plumbagin-stimulated ERK1/2 activity. These results suggest that plumbagin activates NAD(P)H oxidase, Src, and PI3K, and that the activated PI3K or PDK1 subsequently stimulate Akt and Ras-Raf-MEK1/2-ERK1/2 in 3T3-L1 cells.
authors.affiliation: Department and Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei 112, Taiwan, ROC.
authors.forename: Su-Jung
authors.initials: SJ
authors.lastname: Yang
authors.forename: Shi-Chuan
authors.initials: SC
authors.lastname: Chang
authors.forename: Hui-Chin
authors.initials: HC
authors.lastname: Wen
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Chen
authors.forename: Jyh-Fei
authors.initials: JF
authors.lastname: Liao
authors.forename: Chung-Ho
authors.initials: CH
authors.lastname: Chang
mesh_terms: D041721:3T3-L1 Cells; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002867:Chromones / Q000494:pharmacology; D004347:Drug Interactions; D004789:Enzyme Activation; D005419:Flavonoids / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000096:biosynthesis*; D009025:Morpholines / Q000494:pharmacology; D009285:Naphthoquinones / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011090:Polyenes / Q000494:pharmacology; D053284:Polyunsaturated Alkamides / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000096:biosynthesis*; D011743:Pyrimidines / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*; D019061:src-Family Kinases / Q000037:antagonists & inhibitors*
chemical_list: C412373:AG 1879; D000972:Antineoplastic Agents, Phytogenic; D002867:Chromones; D005419:Flavonoids; D016166:Free Radical Scavengers; D009025:Morpholines; D009285:Naphthoquinones; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011090:Polyenes; D053284:Polyunsaturated Alkamides; D011743:Pyrimidines; D013481:Superoxides; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019061:src-Family Kinases; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; C054474:manumycin; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; C014758:plumbagin