Laminin Receptor Characterization in Acute Myeloid Leukemia: Integrin α7β1 Defines non-Leukemic Stem Cells with Migratory Potential

ABSTRACT Interactions with the bone marrow (BM) niche are crucial for promoting self-renewal and survival of acute myeloid leukemia (AML) cells. Consequently, AML cells express a variety of surface receptors to engage with BM niche cells and extracellular matrix proteins, including laminins. Despite the association of laminin receptor expression with stemness in healthy hematopoiesis, the role of laminin receptors in AML remains poorly understood. In this study, we present a comprehensive examination of the laminin receptors integrin α3β1, α6β1, α7β1 and basal cell adhesion molecule (BCAM) in AML. We demonstrate that high mRNA expression of all four laminin receptors correlates with poor overall survival. Notably, integrin α6 and α7 display the highest cell surface presentation among the examined laminin receptors and are higher expressed on AML cells compared to healthy controls. Moreover, our results indicate that integrin α7 expression allows to distinguish between leukemic stem cells (LSC) and non-LSC populations. Specifically, integrin α7 appears to mark non-LSC with enhanced migratory potential. Together, our results confirm the association of high laminin receptor expression with poor prognosis and establish integrin α7 as marker of high migratory non-LSC. Competing Interest Statement The authors have declared no competing interest. Abbreviations - A - ampere - ACK - ammonium–chloride–potassium - AML - acute myeloid leukemia - BCAM - basal cell adhesion molecule - BM - bone marrow - BSA - bovine serum albumin - Cas9 - CRISPR associated protein 9 - CB - cord blood - cDNA - complementary DNA - CFU - colony-forming unit - cm2 - square centimeters - DAPI - 4′,6-diamidin-2-phenylindol - ddH2O - double-distilled water - DEG - differentially expressed genes - DMSO - dimethyl sulfoxide - ECM - extracellular matrix - EDTA - ethylene diamine tetraacetic acid - ELN - European leukemiaNet - EMT - epithelial-to mesenchymal transition - FACS - fluorescence-activated cell sorting - FBS - fetal bovine serum - FC - fold change - FDR - false discovery rate - FLT3-L - fms-related receptor tyrosine kinase 3 ligand - g - gram - GAPDH - glyceraldehyde 3-phosphate dehydrogenase - Gb - giga base - G-CSF - granulocyte colony-stimulating factor - GTEx - genotype-tissue expression - GSEA - gene set enrichment analysis - h - hours - HKG - housekeeping gene - HSPC - hematopoietic stem and progenitor cell - HUVEC - human umbilical vein endothelial cells - IL-3 - interleukin-3 - IL-6 - interleukin-6 - ITGA3 - gene encoding integrin α3 - ITGA6 - gene encoding integrin α6 - ITGA7 - gene encoding integrin α7 - KO - knockout - l - liter - LM - laminin - LSC - leukemic stem cell - µg - microgram - µL - microliter - mg - milligram - min - minutes - mL - milliliter - mM - millimolar - MNC - mononuclear cell - NFκB - nuclear factor kappa-light-chain-enhancer of activated B cells - NKG2DL - natural killer group 2D ligand - nm - nanometer - nmol - nanomol - OD - optical density - PB - peripheral blood - PBMC - peripheral blood mononuclear cells - PBS - phosphate-buffered saline - PCR - polymerase chain reaction - Pmol - picomol - qRT-PCR - quantitative real-time polymerase chain reaction - RNP - ribonucleoprotein - RT - room temperature - SCF - stem cell factor - SDC2 - syndecan-2 - SDS - sodium dodecyl sulfate - SDS-PAGE - sodium dodecyl sulfate polyacrylamide gel electrophoresis - sgRNA - single guide RNA - SR-1 - StemRegenin 1 - TBP - TATA-binding protein - TBST - Tris-buffered saline with Tween20 - TCGA - the cancer genome atlas - THBS1 - thrombospondin 1 - TNFα - tumor necrosis factor alpha - tpm - transcripts per million - TPO - thrombopoietin - UM729 - pyrimido-indole derivate - V - volt - VCAN - versican