Overexpressing SOCS3 or inhibiting EZH2 rescued MCF‐10A or MCF‐7 cells from DANCR‐stimulated viability, migration, invasion, EMT or cancer stemness. (A,B) MTT assay showed that overexpressing SOCS3 in DANCR cells (DANCR + SOCS3) or treating these cells with EZH2 inhibitor (DANCR + GSK‐126) reduced DANCR‐stimulated cell viability. Transwell migration (C,D) and invasion (E,F) assay showed overexpression of SOCS3 or inhibition of EZH2 inhibited DANCR‐stimulated migration and invasion of indicated cells. (G,H) Western blot on EMT‐related biomarkers, E‐cadherin, and Vimentin showed that although DANCR stimulated EMT in MCF‐10A and MCF‐7 cells, overexpression of SOCS3 or treatment of cells with GSK‐126 was sufficient to abolish the effect of DANCR. Representative western images are shown in (G) and the quantification in (H). (I,J) Mammosphere assay showed that DANCR significantly promoted mammosphere formation, which was reversed by overexpression of SOCS3 or inhibition of EZH2. Representative images of mammosphere formed in each group are shown in (I) and the quantification on the number of mammospheres in (J). (K,L) Western blot showed DANCR increased the expression of stemness‐related biomarkers CD44, CD133, OCT3/4, and NANOG, which was inhibited by overexpressing SOCS3 or inhibiting EZH2. n = 3, data are shown as mean ± SD. One‐way ANOVA was used to determine statistical significance: *P < 0.05, **P < 0.01.