qPCR, Western blot, Luciferase reporter assay, in vitro knockdown, etc.
NLCLC tissues, NLCLC cell lines, A549, NCI-H460, NCI-H1299 and NCI-H358
EGFR AS1 was abnormally upregulated in NSCLC tissues compared with adjacent normal lung tissues. Furthermore, patients with NSCLC with increased expression of EGFR AS1 had a poor prognosis. EGFR AS1 knockdown significantly inhibited NSCLC malignancy in vitro, including cell proliferation and chemoresistance. Furthermore, the expression levels of EGFR AS1 were increased in plasma samples from patients with cisplatin-based chemotherapy resistance. Bioinformatics analysis and a luciferase reporter assay confirmed that EGFR AS1 mediated cell proliferation and chemoresistance through directly binding to microRNA 223. Therefore, EGFR AS1 overexpression-induced chemoresistance can contribute to poor prognosis in NSCLC.