Notopterol Suppresses IL-17-Induced Proliferation and Invasion of A549 Lung Adenocarcinoma Cells via Modulation of STAT3, NF-κB, and AP-1 Activation

Interleukine-17 is a proinflammatory cytokine that promotes lung cancer growth and progression though the activation of the STAT3, NF-κB, and AP-1 signaling pathways. Therefore, blocking the IL-17-induced oncogenic pathway is a new strategy for the treatment of lung cancer. Notopterol, a furanocoumarin, has demonstrated anti-tumor effects in several types of tumors. However, its molecular function in relation to the IL-17-induced proliferation and invasion of A549 lung adenocarcinoma cells remains unknown. Here, notopterol exhibited an inhibitory effect on IL-17-promoted A549 cell proliferation and induced G0/G1 cell cycle arrest. Western blot analysis revealed that notopterol inhibited the expression of cell-cycle-regulatory proteins, including cyclin D1, cyclin E, CDK4, and E2F. Moreover, notopterol blocked IL-17-induced A549 cell migration and invasion by regulating the epithelial–mesenchymal transition (EMT) and reducing the expression of extracellular degradation enzymes. At the molecular level, notopterol treatment significantly down-regulated the IL-17-activated phosphorylation of Akt, JNK, ERK1/2, and STAT3, leading to a reduced level of transcriptional activity of NF-κB and AP-1. Collectively, our results suggest that notopterol blocks IL-17-induced A549 cell proliferation and invasion through the suppression of the MAPK, Akt, STAT3, AP-1, and NF-κB signaling pathways, as well as modulating EMT.