Granulocyte colony-stimulating factor inhibits CXCR4/SDF-1α signaling and overcomes stromal-mediated drug resistance in the HL-60 cell line

Abstract

Combining cytarabine, aclarubicin and granulocyte colony-stimulating factor (G-CSF) has demonstrated marked efficacy in the treatment of elderly and relapsed/refractory patients with acute myeloid leukemia (AML); however, the role of G-CSF remains poorly understood. The present study aimed to investigate the ability of G-CSF to overcome stromal-mediated drug resistance and the underlying molecular mechanism. Two types of co-culture models were established in the HS-5 human bone marrow/stromal and HL-60 human promyelocytic leukemia cell lines, in order to imitate the interactions between stromal and leukemia cells , which is mediated by the stromal cell-derived factor (SDF)-1α signaling axis. In the present study, HL-60 cells were attracted and adhered to HS-5 cells using migration assay and flow cytometry, respectively; however, these interactions were inhibited by treatment with G-CSF and/or the C-X-C chemokine receptor type 4 (CXCR4) antagonist, AMD3100. Co-culture with HS-5 cells, including direct and indirect contact, protected HL-60 cells against spontaneous apoptosis or drug-induced apoptosis; however, these protective effects were disrupted by treatment with G-CSF and/or AMD3100. Notably, G-CSF and/or AMD3100 did not alter cell viability or apoptosis when HL-60 cells were cultured with medium alone. In addition, G-CSF significantly reduced the expression levels of surface CXCR4 protein, total CXCR4 protein and CXCR4 mRNA, and significantly upregulated the expression of microRNA (miR)-146a. Conversely, AMD3100 significantly reduced surface CXCR4 expression levels, but not the total CXCR4, CXCR4 mRNA or miR-146a expression levels. The results of the present study suggested that interfering with the CXCR4/SDF-1α signaling axis via G-CSF inhibited the migration and adhesion of HL-60 cells to HS-5 cells and eliminated HS5 cell-mediated protective effects. Furthermore, G-CSF administration reduced CXCR4 expression levels by upregulating the expression of miR-146a, whereas AMD3100 appeared to be predominantly dependent on receptor internalization. Therefore, a G-CSF/miR-146a/CXCR4 pathway may explain how G-CSF inhibits CXCR4/SDF-1α signaling and overcomes stromal cell-mediated drug resistance in acute myeloid leukemia.

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

“…A very low level of miRNA-146a does not interfere with the signaling pathway of CXCR4/SDF-1 and enables efficient HSC adhesion in bone marrow niches. 28,50,51 The downregulated miRNA-223 expression observed between the conditioning treatment and day +7 after HSCT, as compared to the baseline, could have resulted from the significant decline in WBC or HSC progenitors and the inhibition of their differentiation. 34,36 The restricted expression of miRNA-223 in the early post-transplant period can be also explained by the inflammatory processes in HSC microenvironment after transplantation.…”

“…28 Upregulated levels of miRNA-146a influence CXCR4 mRNA, which leads to slower HSC settling in bone marrow niches and consequently longer homing. 28 In the present study, we observed a correlation of miRNA-146a with MMP-9…”

“…28 The impact of this miRNA on CXCR4 mRNA leads to the disruption of CXCR4 and the stromal-derived factor 1 (SDF-1) complex, which results in a more efficient mobilization of HSCs and slower homing. 28…”

Selected factors influencing angiogenesis and hematopoietic niche

“…MiRNA-146a regulates mobilization of HSC as well as their homing after bone marrow transplantation [90][91][92][93]. Previous research has shown that under the influence of G-CSF, expression of CXCR4 chemokine receptor mRNA and protein in AML cells was decreased while the level of miRNA-146a was increased [94]. MiRNA-146a affects the CXCR4 mRNA, which leads to disruption of the SDF-1/ CXCR4 signaling pathway.…”

“…MiRNA-146a affects the CXCR4 mRNA, which leads to disruption of the SDF-1/ CXCR4 signaling pathway. It results in more efficient mobilization of HSCs, and slower homing [94]. Urocinase-type plasminogen activator receptor (uPAR), known to be modulated by miRNA-146a, by binding vitronectin is involved in extracellular matrix degradation, cell adhesion, and migration.…”