Open AccessPS980 GRIK5 DRIVES SELF RENEWAL PATHWAYS IN HUMAN ACUTE MYELOID LEUKEMIA CELLS
Author(s) -
Xia J.,
Garg S.,
He L.,
Jagdhane P.,
Carsten M.T.,
Caroline P.
Publication year - 2019
Publication title -
hemasphere
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 11
ISSN - 2572-9241
DOI - 10.1097/01.hs9.0000562220.27971.d0
Subject(s) - myeloid leukemia , haematopoiesis , biology , progenitor cell , leukemia , cancer research , gene knockdown , microbiology and biotechnology , small hairpin rna , stem cell , immunology , cell culture , genetics
Background: Acute myeloid leukemia (AML) is characterized by a block in differentiation and uncontrolled proliferation of immature hematopoietic precursor cells. Self‐renewing leukemia stem cells (LSCs) are supposed to initiate and promote the disease. In our previous study, we had identified a set of genes associated with high LSC frequency in normal karyotype AML. Among these, we identified the Glutamate receptor ionotropic, kainate 5 (GRIK5) coding for a transmembrane protein, which is known to be expressed in the central nervous system as a ligand‐gated ion channel receptor. Aims: In this study, we aimed to understand the functional role of GRIK5 in normal HSPCs and AML cells. In particular, we investigated how GRIK5 drives self‐renewal pathways in AML and whether GRIK5 might represent a novel cell surface target for anti‐leukemic therapy. Methods: We performed knockdown (KD) experiments using small hairpin (sh) RNAs to determine whether GRIK5 was essential for proliferation, differentiation, and survival of primary human cord blood CD34+ HSPCs, leukemic cell lines, and primary human‐derived AML xenograft cells. Furthermore, lentivirally transduced HSPCs and leukemia cells were analyzed in vitro for proliferative output, viability, immunophenotype, and colony formation potential. RNA sequencing (RNA‐Seq) and whole cell mass spectrometry followed by enrichment analysis were used to identify key signaling pathways affected by GRIK5 KD. Results: We found that knockdown of GRIK5 expression strongly impaired leukemic cell proliferation and totally abrogated human leukemic engraftment in immunocompromised mice. In the healthy system, however, GRIK5 KD predominantly reduced the proliferative output of more committed progenitors, while more immature HSPCs were less affected. RNA‐Seq data points towards a major involvement in several key self‐renewal pathways. Summary/Conclusion: Here we found that the surface receptor GRIK5 is overexpressed in the majority of AML samples compared to healthy HSPCs. GRIK5 plays a pivotal role in proliferation, differentiation, and engraftment capacity of primary human leukemia cells in xenotransplantation assays and might, therefore, be used as a novel therapeutic target for anti‐leukemic therapies.