title: Adenosine triphosphate regulates NADPH oxidase activity leading to hydrogen peroxide production and COX-2/PGE2 expression in A549 cells.
abstract: Non-small cell lung carcinoma (NSCLC) accounts for most of all lung cancers, which is the leading cause of mortality in human beings. High level of cyclooxygenase-2 (COX-2) is one of the features of NSCLC and related to the low survival rate of NSCLC. However, whether extracellular nucleotides releasing from stressed resident tissues contributes to the expression of COX-2 remains unclear. Here, we showed that stimulation of A549 cells by adenosine 5'-O-(3-thiotriphosphate) (ATPγS) led to an increase in COX-2 gene expression and prostaglandin E(2) (PGE(2)) synthesis, revealed by Western blotting, RT-PCR, promoter assay, and enzyme-linked immunosorbent assay. In addition, ATPγS induced intracellular reactive oxygen species (ROS) generation through the activation of NADPH oxidase. The increase of ROS level resulted in activation of the c-Src/epidermal growth factor receptor (EGFR)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/nuclear factor (NF)-κB cascade. We also found that activated Akt was translocated into the nucleus and recruited with NF-κB and p300 to form a complex. Thus, activation of p300 modulated the acetylation of histone H4 via the NADPH oxidase/c-Src/EGFR/PI3K/Akt/NF-κB cascade stimulated by ATPγS. Our results are the first to show a novel role of NADPH oxidase-dependent Akt/p65/p300 complex formation that plays a key role in regulating COX-2/PGE(2) expression in ATPγS-treated A549 cells. Taken together, we demonstrated that ATPγS stimulated activation of NADPH oxidase, resulting in generation of ROS, which then activated the downstream c-Src/EGFR/PI3K/Akt/NF-κB/p300 cascade to regulate the expression of COX-2 and synthesis of PGE(2) in A549 cells. Understanding the regulation of COX-2 expression and PGE(2) release by ATPγS on A549 cells may provide potential therapeutic targets of NSCLC.
authors: Dept. of Pharmacology, College of Medicine, Chang Gung Univ., Kwei-San, Tao-Yuan, Taiwan.
authors: Chih-Chung
authors: CC
authors: Lin
authors: I-Ta
authors: IT
authors: Lee
authors: Wan-Ling
authors: WL
authors: Wu
authors: Wei-Ning
authors: WN
authors: Lin
authors: Chuen-Mao
authors: CM
authors: Yang
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology; D000081247:CSK Tyrosine-Protein Kinase; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism*; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D018836:Inflammation Mediators / Q000494:pharmacology / Q000502:physiology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011505:Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic; D015854:Up-Regulation; D050880:p300-CBP Transcription Factors / Q000378:metabolism; D019061:src-Family Kinases
chemical_list: D018836:Inflammation Mediators; D008562:Membrane Glycoproteins; D016328:NF-kappa B; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D050880:p300-CBP Transcription Factors; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D051057:Proto-Oncogene Proteins c-akt; D015232:Dinoprostone