The PPAR尾 agonist L-165041 promotes VEGF mRNA stabilization in HPV18-harboring HeLa cells through a receptor-independent mechanism

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• 作者：Emmanuelle Roche ; Isabelle Lascombe ; Hugues Bittard ; Christiane Mougin ; Sylvie Fauconnet
• 关键词：ARE ; AU-rich element ; CHX ; cycloheximide ; ELAV ; Embryonic Lethal Abnormal Vision ; ERK1/2 ; Extracellular signal Regulated Kinase1/2 ; HPV ; Human Papillomavirus ; HuR ; Human antigen R ; MAPK ; Mitogen-Activated Protein Kinase ; mTOR ; mammalian Target Of Rapamycin ; PARP ; PolyADP Ribose Polymerase ; PFT-伪 ; Pifithrin-伪 ; PKC ; Protein Kinase C ; PMA ; Phorbol-12-myristate-13-acetate ; PPAR ; Peroxisome Proliferator-Activated Receptor ; PPRE ; Peroxisome Proliferator Responsive Element ; RBP ; RNA-Binding Protein
• 刊名：Cellular Signalling
• 出版年：February, 2014
• 年：2014
• 卷：26
• 期：2
• 页码：433-443
• 全文大小：918 K

文摘

Peroxisome Proliferator-Activated Receptor-尾 (PPAR尾) is a ligand-inducible transcription factor activated by both natural (fatty acids and derivatives) and high affinity synthetic agonists. It is thought to play a role in angiogenesis development and Vascular Endothelial Growth Factor (VEGF) regulation but its contribution remains unclear. Until now, the PPAR尾 agonism effect on VEGF expression in cervical cancer cells was unknown. This led to our interest in assessing the effect of PPAR尾 activation on the regulation of different VEGF isoforms mRNA expression and the impact of E6 viral oncoprotein and its target p53 on this regulation in cervical cancer cells. Here, we showed that the PPAR尾 agonist L-165041 induces VEGF₁₂₁, VEGF₁₆₅ and VEGF₁₈₉ expression in HPV (Human Papillomavirus) positive HeLa cells but not in HPV negative cells. The underlying mechanisms did involve neither E6 oncoprotein nor p53. We highlighted a novel mode of PPAR尾 ligand action including a post-transcriptional regulation of VEGF mRNA expression through the p38 MAPK signaling pathway and the activation of the mRNA-stabilizing factor HuR. But most importantly, we clearly demonstrated that L-165041 acts independently of PPAR尾 since its effect was not reversed by a chemical inhibition with a specific antagonist and the siRNA-mediated knockdown of the nuclear receptor. As VEGF is crucial for cancer development, the impact of PPAR尾 ligands on VEGF production is of high importance. Thus, the molecular mechanism of their action has to be elucidated and as a result, PPAR尾 agonists currently in clinical trials should be carefully monitored.