Abstract 1787: miR-150 as a predictor of hematopoietic reconstitution after myeloablation

Abstract The identification of biomarkers that allow evaluation of myeloablation and hematopoietic reconstitution time frame is important for tailoring the radiation or chemo therapy in cancer patients. The fate of hematopoietic cells is regulated at multiple stages by various genes and regulatory microRNAs. In this context, miR-150 has been demonstrated as a major regulator of lymphoid lineage differentiation and development. Our mouse model studies shows a novel role of miR-150 in imparting radiation resistance. We observed a prolonged survival benefit in mice where both the copies of miR-150 genes are deleted in comparison to that of wildtype mice in the same C57BL/6 background (p<0.05). The survival benefit after total body irradiation was found to be associated with lower apoptosis and early reconstitution in hematopoietic stem cells (lin-ckit+sca1+/-) in bone marrow. Furthermore, the recovery kinetics at sub lethal dose (6Gy) showed that HSCs in miR-150-/- mice recovers faster. Myeloid (Mac1+Gr1+) and lymphoid (CD45+CD19+) lineage cells reconstitutes within 14 days after radiation in KO mice compared to 21 days or more in WT mice. We observed a statistically significant upregulation in myeloid cells in KO mice which implicates an early recovery from radiation induced neutropenia and hence more survivability. In addition, the enhanced bone marrow reconstitution was reflected in peripheral blood counts where a noticeable difference (p<0.05) in blood RBCs lymphocytes, monocytes, neutrophils, and basophiles were noted when compared sub lethally irradiated KO with WT mice. Altogether we demonstrate that the level of miR-150 regulates the bone marrow cells distribution and hence could be targeted for achieving accelerated hematopoietic recovery after myeloablation. These findings may be translated to human cancer patients for therapy guiding based on miR-150 expression level. Besides its use in prediction of reconstitution, miR-150 in the circulating system could provide a direct readout of functional marrow and hence hematological acute radiation syndrome (H-ARS). Citation Format: Marshleen Yadav, Arnab Chakravarti, Naduparambil K. Jacob. miR-150 as a predictor of hematopoietic reconstitution after myeloablation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1787. doi:10.1158/1538-7445.AM2017-1787