AFAP1-AS1, a long noncoding RNA upregulated in lung cancer and promotes invasion and metastasis

Long noncoding RNAs (lncRNAs) have emerged as a major regulator of cancer. Significant fraction of lncRNAs is represented on widely used microarray platforms; however, many of which have no known function. To discover novel lung cancer-related lncRNAs, we analyzed the lncRNA expression patterns in five sets of previously published lung cancer gene expression profile data that were represented on Affymetrix HG-U133 Plus 2.0 array, and identified dysregulated lncRNAs in lung cancer. One lncRNA, actin filament associated protein 1 antisense RNA1 (AFAP1-AS1), was the most significantly upregulated in lung cancer and associated with poor prognosis. In vitro experiments demonstrated that AFAP1-AS1 knockdown significantly inhibited the cell invasive and migration capability in lung cancer cells. AFAP1-AS1 knockdown also increased the expression of its antisense protein coding gene, actin filament associated protein 1 (AFAP1), and affected the expression levels of several small GTPase family members and molecules in the actin cytokeratin signaling pathway, which suggested that AFAP1-AS1 promoted cancer cell metastasis via regulation of actin filament integrity. Our findings extend the number of noncoding RNAs functionally implicated in lung cancer progression and highlight the role of AFAP1-AS1 as potential prognostic biomarker and therapeutic target of lung cancer.