High grade gliomas impact cell fate differentiation of hematopoietic stem and progenitor cells in the bone marrow

Abstract Glioblastoma (GBM) remains a deadly disease with an overall survival of 18 months. Despite advances in cancer immunotherapy, especially in the context of solid tumors derived outside of the central nervous system, GBM remains difficult to treat. This may be due, in part, to reduced T cell function and expansion of suppressive myeloid cells within the periphery. Here we sought to determine if GBM impacts the phenotype and gene expression of progenitor populations within the bone marrow where hematopoietic stem and progenitor cells (HSPCs) originate. Using RNAseq, we found HSPCs derived from intracranial glioma-bearing mice possess altered gene expression relative to HSPCs derived from non-tumor-bearing mice. In addition, we found glioma-bearing mice possess an expansion of myeloid-derived suppressor cells (MDSCs) within their bone marrow and are significantly more suppressive on T cell proliferation and T cell-mediated tumor cell killing than MDSCs isolated from non-tumor-bearing mice. We also determined HSPCs derived from glioma-bearing mice are more likely to differentiate into MDSCs than HSPCs derived from non-tumor-bearing mice. Interestingly, we found components of immunotherapy are capable of redirecting cell fate differentiation of glioma-bearing HSPCs. We determined HSPCs cultured in T cell supernatants are capable redirecting their differentiation from suppressive MDSCs towards stimulatory DCs. Finally, using two murine glioma models, we found adoptive cellular therapy using HSPCs derived from glioma-bearing mice is capable of providing a similar survival benefit as adoptive cellular therapy using HSPCs derived from non-tumor-bearing mice.