A Tumor Suppressor Function of LncRNA-X in Bcr-Abl-induced Tumorigenesis. Homo sapiens

Aberrant long noncoding RNA (lncRNA) expression has been described in many human malignancies, including leukemia. Philadelphia-positive (Ph+) chronic myeloid leukemia (CML) is a stem cell disease induced by Bcr-Abl hybrid gene. Here we attempt to identify lncRNAs associated with CML by analyzing lncRNA expression profiles in K562 cells when Bcr-Abl gene silenced. LncRNA microarray analysis revealed a group of lncRNAs that exhibit Bcr-Abl-dependent expression. In this study, we focused on lncRNA-X that was downregulated by Bcr-Abl, suggesting that lncRNA-X might have a function of tumor suppression. We showed that lncRNA-X over-expression delays Bcr-Abl-induced tumorigenesis in vivo, maybe through its effect on cell survival by modulating STAT5-dependent expression of anti-apoptotic Bcl-XL protein. We also demonstrated that lncRNA-X may affect tumor formation behavior of Bcr-Abl-transformed cells by regulating signaling pathways associated with leukemia stem cells of CML. Together, these results suggest that lncRNA-X suppresses Bcr-Abl-induced tumorigenesis, and the tumor suppressor function of lncRNA-X may be of significance for exploring novel therapeutic strategies for treating CML. This microarray was performed to identify lncRNAs associated with Bcr-Abl-induced chronic myeloid leukemia (CML). Overall design: Total RNAs were isolated from three independent groups of K562 cells treated with anti-Bcr-Abl or anti-luciferase shRNAs respectively, using TRIzol reagent (Invitrogen, Carlsbad, CA). Samples were amplified and labeled using a NimbleGen One-Color DNA Labeling Kit.