Upregulation of snoRA42 in CD133- cells isolated from NSCLC cell lines increases the in vitro tumorigenicity. (A) H-1944- and Calu-1-derived CD133- cells transduced with pCMV-snoRA42 displayed an elevated level of snoRA42 expression. (B) Effect of snoRA42 overexpression on sphere formation of H-1944- and Calu-1-derived CD133- cells. H-1944- and Calu-1-derived CD133- cells transduced with pCMV-snoRA42 had a higher growth rate of spheres compared with CD133- cells transduced with vector. (C) Effect of enforced expression of snoRA42 in H-1944- and Calu-1-derived CD133- cells on colony formation in soft agar. pCMV-control transduced and pCMV-snoRA42-transduced CD133- cells were allowed to differentiate for four weeks in soft agar, respectively. Forced expression of snoRA42 significantly increased colony formation capability of CD133- cells. (D) Ectopic expression of snoRA42 improved migration of H-1944-derived CD133- cells. A wound scratch assay was used to measure migration rate of cells transduced with pCMV-control and pCMV-snoRA42 24 h post treatment. Forced snoRA42 expression in CD133- cells caused a significant increase in migration capability of CD133- cells. *P values <0.05. The number of cells used in each experiment can be found in Methods.