RETRACTED: ATP Mediates NADPH Oxidase/ROS Generation and COX-2/PGE2 Expression in A549 Cells: Role of P2 Receptor-Dependent STAT3 Activation (Retracted article. See vol. 17, 2022)

Background: Up-regulation of cyclooxygenase (COX)-2 and its metabolite prostaglandin E-2 (PGE(2)) are frequently implicated in lung inflammation. Extracellular nucleotides, such as ATP have been shown to act via activation of P2 purinoceptors, leading to COX-2 expression in various inflammatory diseases, such as lung inflammation. However, the mechanisms underlying ATP-induced COX-2 expression and PGE(2) release remain unclear. Principal Findings: Here, we showed that ATP gamma S induced COX-2 expression in A549 cells revealed by western blot and real-time PCR. Pretreatment with the inhibitors of P2 receptor (PPADS and suramin), PKC (Go6983, Go6976, Ro318220, and Rottlerin), ROS (Edaravone), NADPH oxidase [diphenyleneiodonium chloride (DPI) and apocynin], Jak2 (AG490), and STAT3 [cucurbitacin E (CBE)] and transfection with siRNAs of PKC alpha, PKC iota, PKC mu, p47(phox), Jak2, STAT3, and cPLA(2) markedly reduced ATP gamma S-induced COX-2 expression and PGE(2) production. In addition, pretreatment with the inhibitors of P2 receptor attenuated PKCs translocation from the cytosol to the membrane in response to ATP gamma S. Moreover, ATP gamma S-induced ROS generation and p47(phox) translocation was also reduced by pretreatment with the inhibitors of P2 receptor, PKC, and NADPH oxidase. On the other hand, ATP gamma S stimulated Jak2 and STAT3 activation which were inhibited by pretreatment with PPADS, suramin, Go6983, Go6976, Ro318220, GF109203X, Rottlerin, Edaravone, DPI, and apocynin in A549 cells. Significance: Taken together, these results showed that ATP gamma S induced COX-2 expression and PGE(2) production via a P2 receptor/PKC/NADPH oxidase/ROS/Jak2/STAT3/cPLA(2) signaling pathway in A549 cells. Increased understanding of signal transduction mechanisms underlying COX-2 gene regulation will create opportunities for the development of anti-inflammation therapeutic strategies.