Study on the mechanism of CXCL12/CXCR4-axis-mediated upregulation of IL-8 and IL-6 on the biological function of acute T lymphocyte leukaemia cells.

ABSTRACT

Blocking the CXCL12/CXCR4 axis can alter the biological functions of leukaemia cells. We hypothesise that interleukin (IL)-8 and IL-6 play an important role in this process. To test this hypothesis, we established a co-culture model of leukaemia cells and bone marrow stromal cells. Treatment of cells with AMD3100, a CXCR4 antagonist, and G-CSF blocked the CXCL12/CXCR4 axis, inducing biological changes in the leukaemia cells and altering IL-8 and IL-6 levels. Subsequently, after stimulating the CXCL12/CXCR4 axis, specific pathway blockers were employed to assess the role of four candidate signalling pathways in this process. ELISA results confirmed that MG-132 (10 µm) inhibits IL-8 expression and that the NF-κB signalling pathway contributes to this effect. Moreover, treatment with Perifosine, an AKT inhibitor, inhibited IL-6 expression. In addition, changes in the NF-κB signalling pathway inhibited IL-8 expression. Treatment with SP600125, a Jun N-terminal kinase inhibitor, and Perifosine also inhibited IL-8 expression; however, this effect occurred later. IL-6 expression was also lower in the Perifosine group; hence, inhibiting the PI3K/AKT signalling pathway can reduce IL-6 expression. This process requires the participation of multiple signalling pathways to regulate IL-8 and IL-6 expression. Therefore, the associated mechanism is likely to be highly intricate, with potential cross-effects that may impact leukaemia pathogenesis. IL-6 and IL-8 are physiologically regulated by the CXCL12/CXCR4 axis, while the NF-κB and JNK/AP-1 pathways are required for IL-8 expression in T-cell acute lymphoblastic leukaemia. Accordingly, by upregulating IL-8, the bone marrow microenvironment and CXCL12/CXCR4 axis may contribute to T-cell acute lymphoblastic leukaemia pathogenesis.