Urokinase receptor and CXCR4 are regulated by common microRNAs in leukaemia cells

Abstract

The urokinase-type plasminogen activator (uPA) receptor (uPAR) focuses uPA proteolytic activity on the cell membrane, promoting localized degradation of extracellular matrix (ECM), and binds vitronectin (VN), mediating cell adhesion to the ECM. uPAR-bound uPA and VN induce proteolysis-independent intracellular signalling, regulating cell adhesion, migration, survival and proliferation. uPAR cross-talks with CXCR4, the receptor for the stroma-derived factor 1 chemokine. CXCR4 is crucial in the trafficking of hematopoietic stem cells from/to the bone marrow, which involves also uPAR. Both uPAR and CXCR4 are expressed in acute myeloid leukaemia (AML), with a lower expression in undifferentiated and myeloid subsets, and higher expression in myelomonocytic and promyelocytic subsets. We hypothesized a microRNA (miR)-mediated co-regulation of uPAR and CXCR4 expression, which could allow their cross-talk at the cell surface. We identified three miRs, miR-146a, miR-335 and miR-622, regulating the expression of both uPAR and CXCR4 in AML cell lines. Indeed, these miRs directly target the 3′untranslated region of both uPAR- and CXCR4-mRNAs; accordingly, uPAR/CXCR4 expression is reduced by their overexpression in AML cells and increased by their specific inhibitors. Overexpression of all three miRs impairs migration, invasion and proliferation of myelomonocytic cells. Interestingly, we observed an inverse relationship between uPAR/CXCR4 expression and miR-146a and miR-335 levels in AML blasts, suggesting their possible role in the regulation of uPAR/CXCR4 expression also in vivo.

uPAR Knockout Results in a Deep Glycolytic and OXPHOS Reprogramming in Melanoma and Colon Carcinoma Cell Lines

“…The discrepancy in the lactate levels will deserve further investigations as the biological process that produces lactate might be fueled by several metabolic pathways. However, we are confident that the different methods by which we modulated uPAR expression, here and in our previous works [13][14][15][16], might be responsible for the several differences observed. Indeed, using a siRNA, we triggered an acute effect [25], downregulating uPAR expression for a maximum of 72 h while by exploiting the CRISPR/Cas9, we obtained stable KO cell lines, forcing the cells to adapt to uPAR deprivation.…”

“…Given such an abundance of tasks and critical cross-talks, the attempts to control uPAR-mediated multiple functions poses big theoretical and practical problems, such as the privileged inhibition of invasive features that is likely to leave unaltered the signaling properties of the so-called uPAR interactome [4,8]. Our previous efforts, shared by other groups, have pursued the clearing of uPAR from the cell surface by using anti-uPAR ODN (OligoDeoxyNucleotide) [13,14] and miRNA [15], or exploiting uPAR inactivation by specific cleavage systems such as MMP-12 [16] in vitro and in vivo. As a follow-up of our studies, we have used the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/Cas9 technique to obtain the irreversible clearing of uPAR in A375p and A375M6 human melanoma and in HCT116 colon cancer cell lines.…”

miRNA‐15a, miRNA‐16, miRNA‐126, miRNA‐146a, and miRNA‐223 expressions in autologous hematopoietic stem cell transplantation and their impact on engraftment

“…23,24,46 It had been shown that the downregulation of miRNA-126 suppressed angiogenesis, due to significant impairment of VEGF and ANGPT1 expression. [47][48][49] Limited miRNA-126 expression in the first days after HSCT may be associated with aplasia, which is not conducive to the formation of new blood vessels. 47 These findings indicate a multidimensional role of miRNA-126 in the regulation of neovascularization processes.…”

“…35 The processes of migration and adhesion of leukocytes are accompanied by a higher expression of VCAM-1, VEGF, or angiopoietins, which are regulated by miRNA-16, miRNA-126, and miRNA-146a. 15,47,49,51 The biological processes occurring in the early post-transplant period, due to their multifactorial and complicated regulation, are still not fully understood. To the best of our knowledge, miRNAs the secretion of VEGF.…”

Selected factors influencing angiogenesis and hematopoietic niche

“…Under GCS-F stimulation, uPAR enhances chemotactic response to SDF-1. MiRNA-146a downregulates uPAR/CXCR4 pathway, which leads to migration engraftment, and adhesion of hematopoietic stem progenitor cells (HSCPC) to the bone marrow niche [95,96].…”