LncRNA NORAD functions as a competing endogenous RNA to regulate KMT2D expression by targeting miR-204-5p in gastric cancer

Background: Long noncoding RNAs (lncRNAs) are a class of noncoding RNAs implicated in the development of many malignancies, including gastric cancer (GC). Herein, we investigated the functions and molecular mechanisms of non-coding RNA activated by DNA damage (NORAD) in GC. Methods: NORAD expression at the mRNA levels was determined by qRT-PCR assay. Cell proliferation, migration and invasion was detected by CCK-8 assay, in vivo tumor formation assay and Transwell assay. NORAD location was detected by nucleocytoplasmic fractionation assay. The interaction between NORAD and miR-204-5p/KMT2D axis was verified by dual-luciferase reporter gene assay and RIP assay. Results: NORAD was upregulated in GC tissues and cell lines. NORAD silencing repressed cell proliferation and G2/M cell cycle transition in GC. NORAD could act as a ceRNA of miR-204-5p and regulate KMT2D expression. Conclusions: Our study demonstrated that NORAD played as an oncogene in GC, which might provide a new therapeutic target for the disease.