Comprehensive analysis of tumor microenvironment cytokines in Waldenstrom macroglobulinemia identifies CCL5 as a novel modulator of IL-6 activity

Abstract

Although proinflammatory and chemotactic cytokines can profoundly affect the tumor microenvironment, and many of them have been shown to have therapeutic efficacy in preclinical models, the role of these molecules in Waldenströ m macroglobulinemia (WM) remains poorly understood. In this study, simultaneous analysis of WM patient sera and bone marrow biopsies identified a set of dysregulated cytokines including CCL5, G-CSF, and soluble IL-2 receptor, that were significantly elevated in WM patients whereas IL-8 and EGF levels were significantly lower in these patients compared with healthy controls. Interestingly, CCL5 levels positively correlated with features of disease aggressiveness such as elevated IgM levels and bone marrow involvement. IntroductionCytokines are protein mediators that are known to be involved in many biologic processes including cell growth, survival, inflammation, and differentiation. [1][2][3] In the malignant scenario, cytokines can profoundly affect tumor cells directly as well as the surrounding microenvironment, thereby impacting tumor cell biology. Therefore, understanding the composition of the cytokine milieu, particularly in the tumor microenvironment, is an important component of our understanding of the biology of malignant transformation. Targeting cytokines has been shown to have potent therapeutic efficacy in preclinical cancer models. 4,5 Despite the importance of cytokine networks in normal and disease states, only a limited number of studies have addressed the role of cytokines in the regulation of the tumor microenvironment in B-cell malignancies, and in particular, Waldenström macroglobulinemia (WM).WM is characterized by an infiltration of lymphoplasmacytic cells in the bone marrow accompanied by a high circulating monoclonal IgM protein that often leads to serum hyperviscosity. 6 Despite the introduction of multiple therapies, WM remains an incurable disease. Therefore, an understanding of the basic mechanisms underlying disease biology is fundamental to the development of novel therapies. In this study, we used a multiplex immunobead assay to simultaneously measure cytokines, chemokines, angiogenic factors, as well as growth factors and soluble receptors in the sera of WM patients and compared them with healthy donors. Our studies identify CCL5 (also known as regulated on activation, normal T-cell expressed, and secreted [RAN-TES]), G-CSF, and soluble IL-2 receptor ␣ (sIL-2R/CD25) as highly expressed in WM patient sera whereas IL-8 and EGF are down-regulated. Further analysis of CCL5 found that serum CCL5 levels correlated with expression of CCL5 in the bone marrow, IgM, IL-6 and bone marrow involvement by lymphoplasmacytic cells. Further analysis of the interplay between CCL5 and IL-6 indicated that CCL5 induced IL-6 secretion by WM stromal cells and identified the JAK/STAT signaling pathway as a mediator of IgM secretion in response to IL-6 stimulation. Therefore, therapies targeting CCL5 may provide therapeutic efficacy for WM patients by reducing IL-6 secretion by...

CXCL13 levels are elevated in patients with Waldenström macroglobulinemia, and are predictive of major response to ibrutinib

“…The differences in cytokine levels that we observed between HD and WM patients were generally consistent with previous findings in WM, 8 although these studies did not account for MYD88 and CXCR4 mutation status. Several cytokines were found to be lower in Figure 2.…”

“…Serum cytokines are important in WM biology and can be produced either by the malignant cells, the surrounding microenvironmental cells, as well as by cells of the immune system. 8 The anti-tumor effect of ibrutinib may impact all of these compartments, including cytokines that may support growth and survival of tumor cells, and contribute to morbidity in WM, including anemia. 9,10 As such, we aimed to characterize the serum cytokine profile in WM patients based on MYD88 and CXCR4 mutation status, and to characterize serum cytokine and hepcidin changes in response to ibrutinib therapy.…”

Clinical and prognostic implications of low or high level of von Willebrand factor in patients with Waldenström macroglobulinemia

“…29 IL-6 is a proinflammatory cytokine with an important role in normal and malignant B-cell biology; IL-6 up-regulates IgM secretion in WM cells via the JAK/STAT pathway. 30 In addition, VEGF expression on bone marrow mast cells was associated with high VWF concentration. Besides growth and survival signals provided to WM LPCs, 31,32 mast cells regulate endothelial cell proliferation and function by means of mediators such as heparin, histamine, and angiogenic factors, especially VEGF.…”

Molecular pathogenesis of Waldenstrom's macroglobulinemia

“…74 Recently, a functional, stimulating relationship between IL-6, Rantes (CCL5), and IgM secretion was observed and appears to be mediated through the JAK/STAT and PI3K pathways. 75 For the moment, the specific mechanisms of hyper Ig secretion in WM are still not known. GEP data combined with studies of the JAK/STAT pathway could be useful in future investigations into the pathogenic role of IL-6 and JAK/STAT pathways in WM.…”