Abnormal bone remodelling and increased levels of macrophage inflammatory protein-1 alpha (MIP-1alpha) in Waldenström macroglobulinaemia

CCL3 Signaling in the Tumor Microenvironment

Within the tumor microenvironment, chemokines play a key role in immune cell trafficking regulation and immune landscape formulation. CCL3 or macrophage inflammatory protein-1α (MIP-1α), an important chemokine implicated in both immune surveillance and tolerance, has emerged as a prognostic biomarker in both solid and hematological malignancies. CCL3 exerts both antitumor and pro-tumor behavior which is context dependent highlighting the complexity of the underlying interrelated signaling cascades. Current CCL3-directed therapeutic approaches are investigational and further optimization is required to increase efficacy and minimize adverse events.

Soluble PD-1 ligands regulate T-cell function in Waldenstrom macroglobulinemia

Although immune checkpoint molecules regulate the progression of certain cancers, their significance in malignant development of Waldenstrom macroglobulinemia (WM), an incurable low-grade B-cell lymphoma, remains unknown. Recently, cytokines in the bone marrow (BM) microenvironment are shown to contribute to the pathobiology of WM. Here, we investigated the impact of cytokines, including interleukin-6 (IL-6) and IL-21, on immune regulation and particularly on the programmed death-1 (PD-1) and its ligands PD-L1 and PD-L2. We showed that IL-21, interferon γ, and IL-6 significantly induced PD-L1 and PD-L2 gene expression in WM cell lines. Increased PD-L1 and PD-L2 messenger RNA was also detected in patients' BM cells. Patients' nonmalignant BM cells, including T cells and monocytes, showed increased PD-L1, but minimal or undetectable PD-L2 surface expression. There was also very modest PD-L1 and PD-L2 surface expression by malignant WM cells, suggesting that ligands are cleaved from the cell surface. Levels of soluble ligands were higher in patients' BM plasma and blood serum than controls. Furthermore, IL-21 and IL-6 increased secreted PD-L1 in the culture media of WM cell lines, implying that elevated levels of soluble PD-1 ligands are cytokine mediated. Soluble PD-1 ligands reduced T-cell proliferation, phosphorylated extracellular signal-regulated kinase and cyclin A levels, mitochondrial adenosine triphosphate production, and spare respiratory capacity. In conclusion, we identify that soluble PD-1 ligands are elevated in WM patients and, in addition to surface-bound ligands in WM BM, could regulate T-cell function. Given the capability of secreted forms to be bioactive at distant sites, soluble PD-1 ligands have the potential to promote disease progression in WM.

Osteoprotegerin is a significant prognostic factor for overall survival in patients with primary systemic amyloidosis independent of the Mayo staging

Bone metabolism has not been systematically studied in primary (AL) amyloidosis. Thus we prospectively evaluated bone remodeling indices in 102 patients with newly diagnosed AL amyloidosis, 35 healthy controls, 35 newly diagnosed myeloma and 40 monoclonal gammopathy of undetermined significance patients. Bone resorption markers (C-telopeptide of type-1 collagen, N-telopeptide of type-1 collagen) and osteoclast regulators (soluble receptor activator of nuclear factor-κB ligand (sRANKL), osteoprotegerin (OPG)) were increased in AL patients compared with controls (P<0.01), but bone formation was unaffected. Myeloma patients had increased bone resorption and decreased bone formation compared with AL patients, while sRANKL/OPG ratio was markedly decreased in AL, due to elevated OPG in AL (P<0.001). OPG correlated with N-terminal pro-brain natriuretic peptide (P<0.001) and was higher in patients with cardiac involvement (P=0.028) and advanced Mayo stage (P=0.001). OPG levels above the upper value of healthy controls was associated with shorter survival (34 versus 91 months; P=0.026), while AL patients with OPG levels in the top quartile had very short survival (12 versus 58 months; P=0.024). In Mayo stage 1 disease, OPG identified patients with poor survival (12 versus >60 months; P=0.012). We conclude that increased OPG in AL is not only a compensation to osteoclast activation but may also reflect early cardiac damage and may identify patients at increased risk of death within those with earlier Mayo stage.

Schnitzler's syndrome: lessons from 281 cases

Schnitzler’s syndrome is an autoinflammatory disorder characterized by the association of a monoclonal IgM (or IgG) gammopathy, a chronic urticarial rash, and signs and symptoms of systemic inflammation, including fever, arthralgias and bone pain. It was first described in 1972. This review summarizes the clinical features, efficacy of therapies, and follow-up data of the 281 cases that have been reported to date. Also, the results of skin histology, bone imaging, laboratory investigations, and studies of the pathogenesis will be discussed, including the pivotal role of interleukin-1 beta in this disorder.

Parathyroid hormone receptor mediates the anti-myeloma effect of proteasome inhibitors

Clinically significant serum parathyroid hormone (PTH) variations have been reported in multiple myeloma (MM) patients treated with proteasome inhibitors. To elucidate the association between serum PTH variations and proteasome inhibition in MM, the effect of PTH and PTHR1 ligands on the proteasome inhibitors bortezomib and carfilzomib in vitro and in vivo was determined. The MM cell lines ARP1, OC1 and 5TGM1 expressed mRNA and protein encoding PTH receptor 1 (PTHR1). Treatment of 5TGM1 cells with either PTH(1-34), bortezomib or carfilzomib alone dose-dependently inhibited 5TGM1 cell proliferation. However, treatment with the potent PTHR1 antagonist [TYR34]PTH(7-34) (PTH(7-34)) had no significant effect on myeloma cell proliferation and cell viability. In contrast, when used in combination with bortezomib or carfilzomib, PTH(7-34) treatment significantly reduced the bortezomib or carfilzomib-associated decrease in cell proliferation. Treatment of the C57BL/KaLwRij mouse myeloma model with either bortezomib or carfilzomib provided a significantly prolonged survival benefit compared to controls (p=0.04; p=0.01 respectfully). This potent anti-myeloma effect was completely abrogated by concomitant treatment with PTH(7-34). These results suggest an important role of the PTHR1 in the anti-myeloma effect of proteosome inhibition.

The bone marrow microenvironment in Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma characterized by widespread involvement of the bone marrow (BM). The BM microenvironment serves as not only a site for disease involvement, but it also appears that the interaction of WM cells with the BM is essential for the pathogenesis of WM. The BM microenvironment consists of the cellular and noncellular compartments. The BM has been shown to regulate cell proliferation, cell cycle, and drug resistance as well as cell dissemination and cell trafficking of WM cells. A better understanding of the role of the BM microenvironment in the pathogenesis of WM can help guide better therapeutic strategies that can target the tumor clone and also regulate the BM microenvironment.

Increased angiogenesis and enhanced bone formation in patients with IgM monoclonal gammopathy and urticarial skin rash: new insight into the biology of Schnitzler syndrome

Schnitzler syndrome is a rare plasma cell disorder the pathogenesis of which is still not fully understood. We evaluated the circulating levels of four major angiogenic cytokines (VEGF, angiogenin, angiopoietin-1 and angiopoietin-2) and six bone remodeling markers (sRANKL, osteoprotegerin, dickkopf-1, CTX, osteocalcin and bone-specific alkaline phosphatase-bALP) in 13 patients with Schnitzler syndrome. At diagnosis, patients had elevated angiogenic cytokines. The mean VEGF levels were almost 3.5-fold higher in Schnitzler syndrome compared to controls, while 10 of 13 patients had higher VEGF than the upper control value. Successful treatment led to a significant reduction in VEGF. Patients with Schnitzler syndrome had increased bone formation (high bALP, osteocalcin and osteoprotegerin) which was not balanced by an increase in bone resorption (normal CTX and sRANKL). These data support a role for VEGF as a new minor criterion in the diagnosis and follow up of Schnitzler syndrome, while the uncoupling of bone remodeling in favor of bone formation justifies the presence of bone densification.

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

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 Waldenström 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. Functional analysis of tumor microenvironment revealed a functional correlation between CCL5 levels and IL-6 levels, a proinflammatory cytokine with an important role in normal and malignant B-cell biology. Furthermore, CCL5 stimulated IL-6 secretion in WM stromal cells resulting in increased IgM secretion by WM malignant cells via the JAK/STAT signaling pathway. Thus, together these results define a novel signaling network in the WM tumor microenvironment controlling IgM secretion and suggest CCL5 as a potential target for the treatment of this disease.

The bone marrow niche in Waldenström's macroglobulinemia

The widespread involvement of the bone marrow with tumor cells indicates that there is continuous cell trafficking of WM cells in and out of the bone marrow leading to cell dissemination in the bone marrow and in the lymph nodes in many patients with WM. The interaction of the WM cells with the bone marrow is critical for the regulation of cell proliferation, cell cycle, drug resistance as well as cell dissemination and trafficking. Advances in understanding the interaction of the tumor clone with the BM microenvironment have led to the development of therapeutic agents that not only target the tumor clone but also regulate the bone marrow microenvironment. Here, we review the role of the cellular and liquid bone marrow compartments in the regulation of cell proliferation and dissemination in WM.

Osteolytic bone resorption in adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATLL) is caused by human T lymphotropic virus type 1 (HTLV-1). Patients with ATLL frequently develop humoral hypercalcemia of malignancy (HHM) resulting from increased osteoclastic bone resorption. Our goal was to investigate the mechanisms of ATLL-induced osteoclastic bone resorption. Murine calvaria co-cultured with HTLV-1-infected cells directly or conditioned media from cell cultures had increased osteoclast activity that was dependent on RANKL, indicating that factors secreted from ATLL cells had a stimulatory effect on bone resorption. Factors released from resorbing bone stimulated proliferation of HTLV-1-infected T-cells. Parathyroid hormone-related protein (PTHrP) and macrophage inflammatory protein-1alpha (MIP-1alpha), both osteoclast stimulators, were expressed in HTLV-1-infected T-cell lines. Interestingly, when HTLV-1-infected T-cells were co-cultured with pre-osteoblasts, the expression of osteoprotegerin (OPG), an osteoclast inhibitory factor, was significantly down-regulated in the pre-osteoblasts. When OPG was added into the ex vivo osteoclastogenesis assay induced by HTLV-1-infected T-cells, osteoclastogenesis was strongly inhibited. In addition, HTLV-1-infected T-cells inhibited expression of early osteoblast genes and induced late genes. These regulators will serve as future therapeutic targets for the treatments of HHM in ATLL.

Current developments in salivary diagnostics

Salivary diagnostics is an emerging field that has progressed through several important developments in the past decade, including the publication of the human salivary proteome and the infusion of federal funds to integrate nanotechnologies and microfluidic engineering concepts into developing compact point-of-care devices for rapid analysis of this secretion. In this article, we discuss some of these developments and their relevance to the prognosis, diagnosis and management of periodontitis, as an oral target, and cardiovascular disease, as a systemic example for the potential of these biodiagnostics. Our findings suggest that several biomarkers are associated with distinct biological stages of these diseases and demonstrate promise as practical biomarkers in identifying and managing periodontal disease, and acute myocardial infarction. The majority of these studies have progressed through biomarker discovery, with the identified molecules requiring more robust clinical studies to enable substantive validation for disease diagnosis. It is predicted that with continued advances in this field the use of a combination of biomarkers in multiplex panels is likely to yield accurate screening tools for these diagnoses in the near future.

Cytokines in the microenvironment of Waldenström's macroglobulinemia

Waldenström's macroglobulinemia (WM) is a lymphoplasmacytic lymphoma characterized by the overproduction of a monoclonal IgM protein that accumulates in the serum. Although the pathologic findings in this disease entity are reasonably well defined, the mechanisms that regulate malignant B-cell growth and monoclonal protein synthesis are less well understood. Cytokines are known to regulate many biologic processes in normal lymphocyte development including immunoglobulin production, and the presence of cytokines within the tumor microenvironment of WM is likely to contribute to malignant cell growth and survival as well as immunoglobulin production. Several studies have suggested that cytokines are potentially dysregulated in WM, however the precise role played by cytokines in WM biology is not clearly defined. This report therefore highlights our current understanding of the role of cytokines in the microenvironment of WM and how they affect malignant cell persistence and function in the bone marrow of patients.

Schnitzler's syndrome: increased levels of bone formation and angiogenesis factors are reduced after successful pefloxacin treatment

Schnitzler's syndrome is characterized by chronic urticaria and monoclonal immunoglobulin (Ig) M gammopathy, with other features including intermittent fever, joint and/or bone pain with radiologic evidence of osteosclerosis, lymphadenopathy, enlarged liver and/or spleen, leukocytosis, and elevated erythrocyte sedimentation rate. The etiology of the syndrome remains obscure, although involvement of various cytokines has been proposed. Bone metabolism and angiogenesis markers are deregulated in Waldenström macroglobulinemia and IgM monoclonal gammopathy of unknown significance, but these markers have not been assessed in Schnitzler's syndrome. Herein, we report a patient with Schnitzler's syndrome who was treated with oral pefloxacin. Serum levels of osteoclast regulators, markers of bone remodeling and angiogenesis cytokines, were measured before treatment and serially after the initiation of treatment. High bone turnover and strikingly elevated levels of angiogenic cytokines were observed at diagnosis. Treatment with pefloxacin resulted in a normalization of the bone remodeling process and a significant reduction of angiogenic cytokines, with rapid and sustained improvement of symptoms, suggesting that these factors might be implicated in the pathophysiology of this syndrome. Furthermore, pefloxacin was proven to be an effective treatment for patients with Schnitzler's syndrome.