a, smFISH showing the ectopically expressed CCAT1-5L lncRNA and MYC promoter RNA are colocalized. CCAT1-5L, red; MYC, green; DAPI, blue. b, Dual RNA–DNA FISH showing the ectopically expressed CCAT1-5L RNA is colocalized with MYC locus. CCAT1-5L lncRNA, red; MYC locus, green; DAPI, blue. c, Western blot showing the ectopically expressed CCAT1-5L boosts MYC levels in HeLa cells. GAPDH served as a loading control. The MYC level is quantified in the middle. d, The depletion or ectopic expression of CCAT1-5L (5L) in HeLa cells influences the proliferation rate. e, Knockdown or ectopic expression of CCAT1-5L affects colony formation. f, CCAT1-5L is critical for cell metastasis in a transwell assay. Scale bar, 50 μm. The experiments in a–c were independently repeated three times with similar results. Data in d–f are mean ± s.d.; n = 3 biological replicates, two-tailed, unpaired t-test.