ObjectiveThis study aimed at probing into the effect of lncRNA NCK1-AS1 on proliferation, migration and invasion of non-small cell lung cancer (NSCLC) cells and its regulatory function on miR-512-5p/p21 molecular axis. MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) was used to assess the expressions of NCK1-AS1 and miR-512-5p in NSCLC tissues and cell lines. The alterations of cell proliferation, migration, invasion and cell cycle were examined by cell counting kit-8 (CCK-8) assay, BrdU experiment, Transwell experiment and flow cytometry, respectively. The dual-luciferase reporter assay and RNA immunoprecipitation experiment were performed to validate the binding relationships between miR-512-5p and NCK1-AS1, and miR-512-5p the 3'UTR of p21 mRNA. Western blot was used to determine the effects of NCK1-AS1 and miR-512-5p on p21 protein expression. ResultsNCK1-AS1 expression was up-regulated in NSCLC tissues and cells, and its high expression was correlated with shorter overall survival time and faster progression of patients. Overexpression of NCK1-AS1 promoted NSCLC cell proliferation, migration and invasion, and accelerated the cell cycle, whereas NCK1-AS1 siRNA inhibited these malignant biological behaviors, and arrested cell cycle. NCK1-AS1 could bind to miR-512-5p, p21 was verified as a target gene of miR-512-5p, and NCK1-AS1 could up-regulate the expression of p21 in NSCLC cells via repressing miR-512-5p expression. ConclusionNCK1-AS1 promotes NSCLC progression by regulating miR-512-5p/p21 molecular axis.