Bcr-Abl oncogene is generated by a reciprocal translocation between chromosome 9 and 22 in human genome, giving Bcr-Abl protein with constitutive tyrosine kinase activity that causes chronic myeloid leukemia (CML) . Few acute lymphoblastic leukemia (ALL) patients also contain Bcr-Abl oncogene. Owing to the development of imatinib, over 90% of CML patients can be cured in recent years. However, the functional relevance of lncRNAs in Bcr-Abl-mediated leukemia remains obscure. Here, we identified a conserved, imatinib-upregulated lncRNA (IUR) family, named lncRNA-IUR37. Upregulation of lncRNA-IUR37 has been detected in both human and mouse Abl-transformed cell lines after imatinib treatment. Interestingly, lncRNA-IUR37 expression levels were significantly lower in leukemic cells derived from Bcr-Abl-positive ALL patients than those in normal control group. Furthermore, altering lncRNA-IUR37 expression remarkably affected survival of Abl-transformed leukemic cells, and tumorigenesis induced by these leukemic cells in xenograft mouse model. Knockdown of lncRNA-IUR37 in transgenic mice significantly promoted Bcr-Abl-mediated primary bone marrow transformation, and leukemia development in leukemia mouse model. These results indicate that lncRNA-IUR37 functions as a suppressor gene in Bcr-Abl-induced tumorigenesis. In addition, we demonstrated that lncRNA-IUR37 directly bound and affected the phosphorylation of STAT5, thereby impacting expression of transferrin receptor protein (TfR or CD71) to regulate leukemic cell survival. Together, our observations suggest that lncRNA-IUR37 is critically involved in Bcr-Abl-mediated leukemogenesis, and provide novel insights into complicated mechanisms underlying cellular transformation by Bcr-Abl oncogene.

Citation Format: Jilong Chen, Xuefei Wang. Identification of a novel imatinib upregulated lncRNA family that is required for efficient cellular transformation by Abl oncogene [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3571.