Fig. 6

Lnc-UTGF promotes migration and invasion of tumor cells by enhancing the TGF-β/SMAD signaling. a–c Silencing lnc-UTGF suppressed migration and invasion of hepatoma cells. Cells were transfected with the indicated RNA duplexes for 36 h (a–b), or two sublines with heterozygous knockout of lnc-UTGF (UTGF-KD-1 and -2) and their control line (UTGF-WT; c) were examined. d Silencing lnc-UTGF attenuated the TGF-β-stimulated migration of hepatoma cells. Cells that were transfected with the indicated RNA duplexes for 24 h were incubated without or with TGF-β for another 24 h. e–f Overexpressing lnc-UTGF promoted migration and invasion of hepatoma cells. Cells stably expressing lnc-UTGF and its control cells (Ctrl) were examined. g–h Silencing of SMAD2/4 or mutation of the SMAD2/4-binding sites in lnc-UTGF attenuated the pro-migration effect of lnc-UTGF. For g, cells stably expressing lnc-UTGF and its control cells (Ctrl) were transfected with the indicated RNA duplexes for 24 h, then incubated without or with TGF-β for 24 h. For h, cells stably expressing full-length lnc-UTGF with wild-type sequence or with mutant SMAD2/4-binding sequences (UTGF-mut) were incubated with TGF-β for 24 h. For a–h, cells were added to transwell chambers without or with Matrigel coatings and incubated for 10 h, followed by staining with crystal violet. All the migrated/invaded cells were counted. siSMAD2/4, cells transfected with the mixture of siRNAs targeting SMAD2 and SMAD4. + or −, cells with (+) or without (−) the indicated treatment. Error bars: SEM from three independent experiments. *, P < 0.05; **, P < 0.01; ns, not significant