Glutathione peroxidase 8 expression on cancer cells and cancer‐associated fibroblasts facilitates lung cancer metastasis

Lung cancer is the leading cause of cancer death worldwide, of which lung adenocarcinoma (LUAD) is the most common subtype. Metastasis is the major cause of poor prognosis and mortality for lung cancer patients, which urgently needs great efforts to be further explored. Herein, glutathione peroxidase 8 (GPX8) was identified as a novel potential pro‐metastatic gene in LUAD metastatic mice models from GEO database. GPX8 was highly expressed in tumor tissues, predicting poor prognosis in LUAD patients. Knockdown of GPX8 inhibited LUAD metastasis in vitro and in vivo, while it did not obviously affect tumor growth. Knockdown of GPX8 decreased the levels of p‐FAK and p‐Paxillin and disturbed the distribution of focal adhesion. Furthermore, GPX8 was overexpressed in cancer‐associated fibroblast (CAF) and associated with CAF infiltration in tumor microenvironment of lung cancer. GPX8 silence on fibroblasts suppressed lung cancer cell migration in the coculture system. BRD2 and RRD4 were the potential transcriptionally regulators for GPX8. Bromodomain extra‐terminal inhibitor JQ1 downregulated GPX8 expression and suppressed lung cancer cell migration. Our findings indicate that highly expressed GPX8 in lung cancer cells and fibroblasts functions as a pro‐metastatic factor in lung cancer. JQ1 is identified as a potential inhibitor against GPX8‐mediated lung cancer metastasis. GPX8 is highly expressed both in lung cancer cells and CAFs, which is a potentially therapeutic target in lung cancer. Knockdown of GPX8 obviously inhibited lung cancer metastasis through the modulation of focal adhesion pathway and GPX8‐mediated IL6 and CCL2 production of CAF may play crucial role for lung cancer metastasis. BET proteins is involved in transcriptional regulation of GPX8 and BET inhibitor is a potential strategy against GPX8‐mediated lung cancer metastasis.