title: Tumor Necrosis Factor-α (TNFα)-induced Ceramide Generation via Ceramide Synthases Regulates Loss of Focal Adhesion Kinase (FAK) and Programmed Cell Death.
abstract: Ceramide synthases (CerS1-CerS6), which catalyze the N-acylation of the (dihydro)sphingosine backbone to produce (dihydro)ceramide in both the de novo and the salvage or recycling pathway of ceramide generation, have been implicated in the control of programmed cell death. However, the regulation of the de novo pathway compared with the salvage pathway is not fully understood. In the current study, we have found that late accumulation of multiple ceramide and dihydroceramide species in MCF-7 cells treated with TNFα occurred by up-regulation of both pathways of ceramide synthesis. Nevertheless, fumonisin B1 but not myriocin was able to protect from TNFα-induced cell death, suggesting that ceramide synthase activity is crucial for the progression of cell death and that the pool of ceramide involved derives from the salvage pathway rather than de novo biosynthesis. Furthermore, compared with control cells, TNFα-treated cells exhibited reduced focal adhesion kinase and subsequent plasma membrane permeabilization, which was blocked exclusively by fumonisin B1. In addition, exogenously added C6-ceramide mimicked the effects of TNFα that lead to cell death, which were inhibited by fumonisin B1. Knockdown of individual ceramide synthases identified CerS6 and its product C16-ceramide as the ceramide synthase isoform essential for the regulation of cell death. In summary, our data suggest a novel role for CerS6/C16-ceramide as an upstream effector of the loss of focal adhesion protein and plasma membrane permeabilization, via the activation of caspase-7, and identify the salvage pathway as the critical mechanism of ceramide generation that controls cell death.
authors: From the Stony Brook Cancer Center, the Department of Medicine, and.
authors: María José
authors: MJ
authors: Hernández-Corbacho
authors: From the Stony Brook Cancer Center, the Department of Medicine, and.
authors: Daniel
authors: D
authors: Canals
authors: From the Stony Brook Cancer Center, the Department of Medicine, and.
authors: Mohamad M
authors: MM
authors: Adada
authors: From the Stony Brook Cancer Center, the Department of Medicine, and.
authors: Mengling
authors: M
authors: Liu
authors: From the Stony Brook Cancer Center, the Department of Medicine, and.
authors: Can E
authors: CE
authors: Senkal
authors: From the Stony Brook Cancer Center, the Department of Medicine, and.
authors: Jae Kyo
authors: JK
authors: Yi
authors: From the Stony Brook Cancer Center, the Department of Medicine, and.
authors: Cungui
authors: C
authors: Mao
authors: From the Stony Brook Cancer Center, the Department of Physiology and Biophysics, Stony Brook University, Health Sciences Center, Stony Brook, New York 11794 and.
authors: Chiara
authors: C
authors: Luberto
authors: From the Stony Brook Cancer Center, the Department of Medicine, and.
authors: Yusuf A
authors: YA
authors: Hannun
authors: From the Stony Brook Cancer Center, the Department of Medicine, and the Northport Veterans Affairs Medical Center, Northport, New York 11768 lina.obeid@stonybrookmedicine.edu.
authors: Lina M
authors: LM
authors: Obeid
mesh_terms: D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002518:Ceramides / Q000096:biosynthesis*; D004789:Enzyme Activation; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D037341:Fumonisins / Q000494:pharmacology; D055785:Gene Knockdown Techniques; D006801:Humans; D061986:MCF-7 Cells; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D002518:Ceramides; D037341:Fumonisins; D014409:Tumor Necrosis Factor-alpha; C056933:fumonisin B1; D010088:Oxidoreductases; C108138:dihydroceramide desaturase; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020169:Caspases
keywords: Ceramide; PTK2 protein tyrosine kinase 2 (PTK2) (focal adhesion kinase) (FAK); cell death; ceramide synthase; fumonisin b1; plasma membrane; sphingolipid