Myeloma bone disease: recent advances in biology, diagnosis, and treatment

Monoclonal Gammopathy of Undetermined Significance

Monoclonal gammopathy of undetermined significance (MGUS) is of considerable clinical importance to primary care physicians given its high prevalence in the general population. MGUS has a variable but lifelong risk for progression to hematologic cancer, such as multiple myeloma, Waldenström macroglobulinemia, or light-chain amyloidosis. In addition, MGUS has been associated with several nonmalignant yet symptomatic disorders that require therapy directed toward eliminating the monoclonal gammopathy. Thus, it is important not only to understand the essentials of diagnosing and monitoring patients with MGUS but also to recognize when to refer patients with MGUS to a specialist.

Bone metabolism parameters and their relation to cytogenetics in multiple myeloma

OBJECTIVES

Our aim was to correlate serum levels of selected markers of bone metabolism and bone marrow microenvironment to cytogenetic changes in patients with multiple myeloma (MM).

METHODS

We assed cytogenetic changes in 308 patients and correlated them with the following levels of bone marrow metabolism: thymidine kinase (TK), β2-microglobulin (b-2-m), Dickkopf-1 protein (DKK-1), C-terminal telopeptide collagen-I (ICTP), N-terminal propeptide of type I procollagen (PINP), receptor for interleukin 6 (rIL-6), vascular cell adhesive molecule-1 (VCAM), soluble intercellular adhesion molecule-1, osteoprotegerin (OPG), hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), syndecan-1 (SYN-1) and Fas antigen.

RESULT

Individuals with delRB1 had lower levels of OPG (M = 7.39 vs. 5.46 pmol/L, p = .025) and VEGF (M = 304 vs. 196 pg/ml; p = .036). t(14;16) was associated with higher β2m levels (M = 7.59 vs. 4.13 mg/L; p = .022) and lower DKK-1 levels (M = 4465 ng/L vs. 12,593). The presence of 1q21 gain was associated with higher levels of TK (M = 100.0 vs. 11.0 IU/L, p = .026) and lower levels of PINP (M = 49.3 vs. 67.4 mg/L, p = .030).

CONCLUSIONS

Our analysis has shown, some cytogenetic changes, especially delRB1, t(14;16) and 1q21gain, which affect the components of the cytokine network in multiple myeloma.

Unstable Pathologic Vertebral Fractures in Multiple Myeloma : Propensity Score Matched Cohort Study between Reconstructive Surgery with Adjuvant Radiotherapy and Radiotherapy Alone

Objective

Although radiotherapy (RT) is recommended for multiple myeloma (MM) involving spine, the treatment of choice between reconstructive surgery with RT and RT alone for pathologic vertebral fractures (PVFs) associated with structural instability or neurologic compromises remains controversial. The purpose of this study was to evaluate the clinical efficacies of reconstructive surgery with adjuvant RT for treatment of MM with PVFs by comparing with matched cohorts treated with RT alone.

Methods

Twenty-eight patients underwent reconstructive surgery followed by RT between 2008 and 2015 in a single institution, for management of PVFs associated with structural instability of the spine and/or neurologic compromises (group I). Twenty-eight patients were treated with RT alone (group II) after propensity score matching in a 1-to-1 format based on instability of the spine, as well as age and performance. Clinical outcomes including the overall survival rates, duration of independent ambulation, neurological status, and numeric rating scale (NRS) for back pain were compared.

Results

Clinical and radiological features before treatment were similar in both groups. The median survival period was similar between the two groups. However, the mean duration of independent ambulation was significantly longer in group I (88.8 months; 95% confidence interval [CI], 66.0–111.5) than in group II (39.4 months; 95% CI, 25.2–53.6) (log rank test; p=0.022). Deterioration of Frankel grade (21.4% vs. 60.7%, p=0.024) and NRS for back pain (2.7±2.2 vs. 5.0±2.7, p=0.000) at the last follow-up were higher in the group II. Treatment-related complications were similar in both groups.

Conclusion

In patients with unstable PVFs due to MM, reconstructive surgery may yield superior clinical outcomes compared with RT alone in maintaining independent ambulation and neurological status, as well as pain control despite similar median survival and complications.

Management of acute spinal cord compression in multiple myeloma

Spinal cord compression (SCC) is a devastating complication of multiple myeloma and has the potential to cause loss of neurological function. The common symptoms of SCC are back pain, motor weakness, and sensory change. Once diagnosed, the patient should be managed as soon as possible to prevent permanent loss of neurological function. Currently, there have been a number of studies describing the mechanism and management experience of SCC in patients with myeloma. The clinical features, diagnostic strategies, and the roles of different therapeutic options are herein reviewed.

Alkaline phosphatase (alp) levels in multiple myeloma and solid cancers with bone lesions: Is there any difference?

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Plasma ALP could be used as a discriminating marker in presence of bone lesions in solid tumor or MM.

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Multiple Myeloma, ALP values were mainly in the range of normality than those observed in patients with solid cancers and bone lesions.

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Lower or normal values, should suggest further investigations such as urinary and serum electrophoresis.

Introduction

Bone involvement in Multiple Myeloma results from increased osteoclast formation and activity that occurs in proximity to myeloma cells. The role of Alkaline Phosphatse (ALP) in this process and the diagnostic significance of plasma levels in patients with MM are unclear.

Aim

To compare plasma ALP levels in patients with MM and solid cancers and metastatic lesions to the bone.

Results

In this observational retrospective study we enrolled 901 patients were enrolled: 440 patients (49%) with Multiple Myeloma, 461 (51%) with solid cancers. All 901 patients had bone lesions. Among patients with Multiple Myeloma, ALP values were mainly in the range of normality than those observed in patients with solid cancers and bone lesions. This difference is independent of stage, number and type of bone lesions.

Conclusion

This study suggests that plasma ALP has a different clinical significance in MM than in other neoplasms and could be used as a discriminating marker in presence of bone lesions. In particular, lower or normal values, should suggest further investigations such as urinary and serum electrophoresis, associated with bone marrow aspirate in case of the presence of a monoclonal component, in order to confirm or exclude a MM diagnosis.

Increased Osteoblastic Activity Suppressed Proliferation of Multiple Myeloma Plasma Cells

STUDY DESIGN

In vitro experimental study.

OBJECTIVE

To investigate the impact of increased osteoblastic activity on the proliferation and survival of multiple myeloma (MM) plasma cells in vitro SUMMARY OF BACKGROUND DATA.: MM is one of representative hematologic malignancies that cause skeletal-related events (SREs) and dysregulation of bone remodeling is known as a key pathomechanism of disease progression and skeletal-related events. However, decreased proliferation of MM at fracture sites is frequently noted in clinical situations regardless of systemic disease activity.

METHODS

Co-culture under various conditions was used to investigate effects of increased osteoblastic activity on survival and proliferation of MM plasma cells. MM plasma cells were cultured in culture media (control) and co-cultured with human mesenchymal stem cells (hMSCs, group I), osteoblasts (OBs) induced from hMSCs (group II) or bone morphogenic protein-2 (BMP-2, group III). Proliferation measured as extracellular signal-regulated kinase (ERK) and immunoglobulin G (Ig G) expression and apoptosis measured as fluorescence-activated cell sorting (FACS) with annexin V method, caspase-3, and stat-3 expression were assessed for cultured MM plasma cells, along with expression of sclerostin.

RESULTS

After 72 hours of co-culture, group II and III showed decreased ERK expression compared with controls. Lower Ig G expression was also noted for groups II and III compared with controls. Group I did not show significantly decreased Ig G and ERK expression compared with controls. Expressions of caspase-3 in groups II and III were higher than controls. Co-culture with hMSCs showed decreased caspase-3 expression compared with control. FACS with annexin V showed higher apoptosis in groups II and III. Sclerostin expression was also decreased in osteoblastic conditions compared with the control and hMSCs co-culture condition.

CONCLUSION

Collectively, our data suggest that increased osteoblastic conditions may provide not only prevention of SREs but also anti-tumor effects on MM cells in the bone marrow environment.

LEVEL OF EVIDENCE

N/A.

ClC5 Decreases the Sensitivity of Multiple Myeloma Cells to Bortezomib via Promoting Prosurvival Autophagy

Resistance to bortezomib (BZ) is the major problem that largely limits its clinical application in multiple myeloma treatment. In the current study, we investigated whether ClC5, a member of the chloride channel family, is involved in this process. The MTT assay showed that BZ treatment decreased cell viability in three multiple myeloma cell lines (ARH77, U266, and SKO-007), with IC₅₀ values of 2.83, 4.37, and 1.91 nM, respectively. Moreover, BZ increased the conversion of LC3B-I to LC3B-II and expressions of beclin-1 and ATG5, concomitantly with a decreased p62 expression. Pharmacological inhibition of autophagy with 3-MA facilitated cell death in response to BZ treatment. Additionally, BZ increased ClC5 protein expression in ARH77, U266, and SKO-007 cells. Knockdown of ClC5 with small interfering RNA sensitized cells to BZ treatment, and upregulation of ClC5 induced chemoresistance to BZ. Furthermore, ClC5 downregulation promoted BZ-induced LC3B-I to LC3B-II conversion and beclin-1 expression, whereas overexpression of ClC5 showed the opposite results in ARH77 cells. Finally, BZ induced dephosphorylation of AKT and mTOR, which was significantly attenuated by ClC5 inhibition. However, ClC5 upregulation further enhanced AKT and mTOR dephosphorylation induced by BZ. Our study demonstrates that ClC5 induces chemoresistance of multiple myeloma cells to BZ via increasing prosurvival autophagy by inhibiting the AKT–mTOR pathway. These data suggest that ClC5 may play a critical role in future multiple myeloma treatment strategies.

Dectin-1 signaling inhibits osteoclastogenesis via IL-33-induced inhibition of NFATc1

Abnormal osteoclast activation contributes to osteolytic bone diseases (OBDs). It was reported that curdlan, an agonist of dectin-1, inhibits osteoclastogenesis. However, the underlying mechanisms are not fully elucidated. In this study, we found that curdlan potently inhibited RANKL-induced osteoclast differentiation and the resultant bone resorption. Curdlan inhibited the expression of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), the key transcriptional factor for osteoclastogenesis. Notably, dectin-1 activation increased the expression of MafB, an inhibitor of NFATc1, and IL-33 in osteoclast precursors. Mechanistic studies revealed that IL-33 enhanced the expression of MafB in osteoclast precursors and inhibited osteoclast precursors to differentiate into mature osteoclasts. Furthermore, blocking ST2, the IL-33 receptor, partially abrogated curdlan-induced inhibition of NFATc1 expression and osteoclast differentiation. Thus, our study has provided new insights into the mechanisms of dectin-1-induced inhibition of osteoclastogenesis and may provide new targets for the therapy of OBDs.

Extensive Remineralization of Large Pelvic Lytic Lesions Following Total Therapy Treatment in Patients With Multiple Myeloma

Osteolytic bone lesions are a hallmark of multiple myeloma (MM) bone disease. Bone destruction is associated with severely imbalanced bone remodeling, secondary to increased osteoclastogenesis and significant osteoblast suppression. Lytic lesions of the pelvis are relatively common in MM patients and are known to contribute to the increased morbidity because of the high risk of fracture, which frequently demands extensive surgical intervention. After observing unexpected radiological improvement in serial large pelvic CT assessment in a patient treated in a total therapy protocol, the radiographic changes of pelvic osteolytic lesions by PET/CT scanning in patients who received Total Therapy 4 (TT4) treatment for myeloma were retrospectively analyzed. Sixty-two (62) patients with lytic pelvic lesions >1 cm in diameter were identified at baseline PET/CT scanning. Follow-up CT studies showed that 27 of 62 patients (43%) with large baseline pelvic lesions achieved significant reaccumulation of radiodense mineralization at the lytic cortical site. The average size of lytic lesions in which remineralization occurred was 4 cm (range, 1.3 to 10 cm). This study clearly demonstrates that mineral deposition in large pelvic lesions occurs in a significant proportion of MM patients treated with TT4, potentially affecting patient outcomes, quality of life, and future treatment strategies. © 2017 American Society for Bone and Mineral Research.

Effects of single-agent bortezomib as post-transplant consolidation therapy on multiple myeloma-related bone disease: a randomized phase II study

This phase II study explored the effects of bortezomib consolidation versus observation on myeloma-related bone disease in patients who had a partial response or better after frontline high-dose therapy and autologous stem cell transplantation. Patients were randomized to receive four 35-day cycles of bortezomib 1·6 mg/m² intravenously on days 1, 8, 15 and 22, or an equivalent observation period, and followed up for disease status/survival. The modified intent-to-treat population included 104 patients (51 bortezomib, 53 observation). There were no meaningful differences in the primary endpoint of change from baseline to end of treatment in bone mineral density (BMD). End-of-treatment rates (bortezomib versus observation) of complete response/stringent complete response were 22% vs. 11% (P = 0·19), very good partial response or better of 80% vs. 68% (P = 0·17), and progressive disease of 8% vs. 23% (P = 0·06); median progression-free survival was 44·9 months vs. 21·8 months (P = 0·22). Adverse events observed ≥15% more frequently with bortezomib versus observation were diarrhoea (37% vs. 0), peripheral sensory neuropathy (20% vs. 4%), nausea (18% vs. 0) and vomiting (16% vs. 0). Compared with observation, bortezomib appeared to have little impact on bone metabolism/health, but was associated with trends for improved myeloma response and survival.

Risk of vertebral compression fractures in multiple myeloma patients: A finite-element study

The purpose of this study was to develop and validate a finite element (FE) model to predict vertebral bone strength in vitro using multidetector computed tomography (MDCT) images in multiple myeloma (MM) patients, to serve as a complementing tool to assess fracture risk. In addition, it also aims to differentiate MM patients with and without vertebral compression fractures (VCFs) by performing FE analysis on vertebra segments (T1-L5) obtained from in vivo routine MDCT imaging scans. MDCT-based FE models were developed from the in vitro vertebrae samples and were then applied to the in vivo vertebrae segments of MM patients (n = 4) after validation. Predicted fracture load using FE models correlated significantly with experimentally measured failure load (r = 0.85, P < 0.001). Interestingly, an erratic behavior was observed in patients with fractures (n = 2) and a more gradual change in FE-predicted strength values in patients without fractures (n = 2). Severe geometric deformations were also observed in models that have already attained fractures. Since BMD is not a reliable parameter for fracture risk prediction in MM subjects, it is necessary to use advanced tools such as FE analysis to predict individual fracture risk. If peaks are observed between adjacent segments in an MM patient, it can be safe to conclude that the spine is experiencing regions of structural instability. Such an FE visualization may have therapeutic consequences to prevent MM associated vertebral fractures.

A mathematical model of cell equilibrium and joint cell formation in multiple myeloma

In Multiple Myeloma Bone Disease healthy bone remodelling is affected by tumour cells by means of paracrine cytokinetic signalling in such a way that osteoclast formation is enhanced and the growth of osteoblast cells inhibited. The participating cytokines are described in the literature. Osteoclast-induced myeloma cell growth is also reported. Based on existing mathematical models for healthy bone remodelling a three-way equilibrium model is presented for osteoclasts, osteoblasts and myeloma cell populations to describe the progress of the illness in a scenario in which there is a secular increase in the cytokinetic interactive effectiveness of paracrine processes. The equilibrium state for the system is obtained. The paracrine interactive effectiveness is explored by parameter variation and the stable region in the parameter space is identified. Then recently-discovered joint myeloma-osteoclast cells are added to the model to describe the populations inside lytic lesions. It transpires that their presence expands the available parameter space for stable equilibrium, thus permitting a detrimental, larger population of osteoclasts and myeloma cells. A possible relapse mechanism for the illness is explored by letting joint cells dissociate. The mathematics then permits the evaluation of the evolution of the cell populations as a function of time during relapse.

Prospective study of signalling pathways in myeloma bone disease with regard to activity of the disease, extent of skeletal involvement and correlation to bone turnover markers

AIMS

The aim of our study was to address the utility of serum levels of selected parameters of myeloma bone disease (MBD) signalling with regard to the pathogenesis of multiple myeloma (MM), activity, markers of bone turnover and extent of skeletal changes.

PATIENTS AND METHODS

We assessed prospectively 77 individuals with monoclonal gammopathies - 46 patients with active MM (AMM), 12 patients with smouldering MM (SMM) and 19 individuals with monoclonal gammopathy of undetermined significance (MGUS) to determine the role of HGF, MIP-1α, Syndecan-1, osteoprotegerin, Activin A, DKK1, Annexin A2 and NF-κB.

RESULTS

We found significant differences of most of the parameters between MGUS and AMM, and with respect to the activity of MM assessed by International Staging System. Most of the parameters of MBD signalling correlated with traditional markers of bone turnover.

CONCLUSIONS

All the signalling pathways were activated in MM with more pronounced osteoclastogenesis in comparison with bone formation but not in MGUS regardless of its risk category, suggesting that MBD is not activated in MGUS until the process of transformation into MM. The parameters of MBD signalling might precede the increase of conventional parameters of bone turnover suggesting their possible role in early indication of anti-resorption therapy.

Identifying bias in CCR1 antagonists using radiolabelled binding, receptor internalization, β-arrestin translocation and chemotaxis assays

BACKGROUND AND PURPOSE

Investigators have suggested that the chemokine receptor CCR1 plays a role in multiple myeloma. Studies using antisense and neutralizing antibodies to CCR1 showed that down-regulation of the receptor altered disease progression in a mouse model. More recently, experiments utilizing scid mice injected with human myeloma cells demonstrated that the CCR1 antagonist BX471 reduced osteolytic lesions, while the CCR1 antagonist MLN-3897 prevented myeloma cell adhesion to osteoclasts. However, information is limited regarding the pharmacology of CCR1 antagonists in myeloma cells.

EXPERIMENTAL APPROACH

We compared several well-studied CCR1 antagonists including AZD4818, BX471, CCX354, CP-481715, MLN-3897 and PS899877 for their ability to inhibit binding of [(125)I]-CCL3 in vitro using membranes prepared from RPMI 8226 cells, a human multiple myeloma cell line that endogenously expresses CCR1. In addition, antagonists were assessed for their ability to modulate CCL3-mediated internalization of CCR1 and CCL3-mediated cell migration using RPMI 8226 cells. As many GPCRs signal through β-arrestin-dependent pathways that are separate and distinct from those driven by G-proteins, we also evaluated the compounds for their ability to alter β-arrestin translocation.

KEY RESULTS

There were clear differences between the CCR1 antagonists in their ability to inhibit CCL3 binding to myeloma cells, as well as in their ability to inhibit G-protein-dependent and -independent functional responses.

CONCLUSIONS AND IMPLICATIONS

Our studies demonstrate that tissue phenotype seems to be relevant with regards to CCR1. Moreover, it appears that for CCR1 antagonists, inhibition of β-arrestin translocation is not necessarily linked to chemotaxis or receptor internalization.

EEN regulates the proliferation and survival of multiple myeloma cells by potentiating IGF-1 secretion

The molecular mechanisms of multiple myeloma are not well defined. EEN is an endocytosis-regulating molecule. Here we report that EEN regulates the proliferation and survival of multiple myeloma cells, by regulating IGF-1 secretion. In the present study, we observed that EEN expression paralleled with cell proliferation, EEN accelerated cell proliferation, facilitated cell cycle transition from G1 to S phase by regulating cyclin-dependent kinases (CDKs) pathway, and delayed cell apoptosis via Bcl2/Bax-mitochondrial pathway. Mechanistically, we found that EEN was indispensable for insulin-like growth factor-1 (IGF-1) secretion and the activation of protein kinase B-mammalian target of rapamycin (Akt-mTOR) pathway. Exogenous IGF-1 overcame the phenotype of EEN depletion, while IGF-1 neutralization overcame that of EEN over-expression. Collectively, these data suggest that EEN may play a pivotal role in excessive cell proliferation and insufficient cell apoptosis of bone marrow plasma cells in multiple myeloma. Therefore, EEN may represent a potential diagnostic marker or therapeutic target for multiple myeloma.

Aseptic necrosis at multiple localisations in a lupus patient with lymphoma

Avascular or aseptic necrosis is a well-defined entity leading to the degradation of cellular elements of the bone. The pathogenesis of osteonecrosis (ON) is still unknown. There are two main types of ON: traumatic or non-traumatic. Several clinical entities could associate with ON, systemic diseases, environmental factors, pregnancy, systemic autoimmune or rheumatic diseases, thrombophilia, corticosteroid therapy, cytotoxic dugs, infections, metabolic and hematologic diseases, etc. Corticosteroids (CS) are still the most frequently used therapeutic options in the early phase and during flares of these diseases. Inflammatory cytokines and antibodies have been described to participate in the pathogenesis of ON. The infiltrative disorders of the bone marrow could also contribute to the development of ON. Hereby, we describe a female patient with NHL followed by SLE in whom ON has developed at least in two localisations. Lupus flare, long-term CS therapy, lymphoma relapse or the presence of antiphospholipid antibodies were excluded. Although the bi-localised ON could be contributed to immunologic factors or trauma, the exact aetiology in this case could not be elucidated.

On the antiquity of cancer: evidence for metastatic carcinoma in a young man from ancient Nubia (c. 1200 BC)

Cancer, one of the world’s leading causes of death today, remains almost absent relative to other pathological conditions, in the archaeological record, giving rise to the conclusion that the disease is mainly a product of modern living and increased longevity. This paper presents a male, young-adult individual from the archaeological site of Amara West in northern Sudan (c. 1200BC) displaying multiple, mainly osteolytic, lesions on the vertebrae, ribs, sternum, clavicles, scapulae, pelvis, and humeral and femoral heads. Following radiographic, microscopic and scanning electron microscopic (SEM) imaging of the lesions, and a consideration of differential diagnoses, a diagnosis of metastatic carcinoma secondary to an unknown soft tissue cancer is suggested. This represents the earliest complete example in the world of a human who suffered metastatic cancer to date. The study further draws its strength from modern analytical techniques applied to differential diagnoses and the fact that it is firmly rooted within a well-documented archaeological and historical context, thus providing new insights into the history and antiquity of the disease as well as its underlying causes and progression.

The effects of bortezomib on bone disease in patients with multiple myeloma

Bortezomib has demonstrated substantial activity in the treatment of patients with multiple myeloma and is widely incorporated into treatment strategies across the different settings. It is interesting to note that data are accumulating to suggest that the activity of bortezomib extends beyond the tumor cell and microenvironment to encompass effects on bone metabolism. Indeed, data from both the preclinical and clinical settings have suggested that bortezomib directly stimulates osteoblast growth and differentiation, while also inhibiting osteoclast development and activity. Notably, in the clinical setting, the bone anabolic effects of bortezomib could be demonstrated by the healing of lytic lesions as noted in some patients. These results are of importance because bone disease is a hallmark of myeloma and therefore any agent that combines antimyeloma activity with positive effects on bone is of substantial interest. However, further studies are needed to establish how the agent should be used for the treatment of patients with bone disease.

Biology and bioinformatics of myeloma cell

Multiple myeloma (MM) is a plasma cell disorder that occurs in about 10% of all hematologic cancers. The majority of patients (99%) are over 50 years of age when diagnosed. In the bone marrow (BM), stromal and hematopoietic stem cells (HSCs) are responsible for the production of blood cells. Therefore any destruction or/and changes within the BM undesirably impacts a wide range of hematopoiesis, causing diseases and influencing patient survival. In order to establish an effective therapeutic strategy, recognition of the biology and evaluation of bioinformatics models for myeloma cells are necessary to assist in determining suitable methods to cure or prevent disease complications in patients. This review presents the evaluation of molecular and cellular aspects of MM such as genetic translocation, genetic analysis, cell surface marker, transcription factors, and chemokine signaling pathways. It also briefly reviews some of the mechanisms involved in MM in order to develop a better understanding for use in future studies.

The proteasome inhibitor bortezomib stimulates osteoblastic differentiation of human osteoblast precursors via upregulation of vitamin D receptor signalling

Interactions of myeloma cells with the bone marrow microenvironment lead to enhanced osteoclast recruitment and impaired osteoblast activity. Recent evidence revealed that the proteasome inhibitor bortezomib stimulates osteoblast differentiation, but the mechanisms are not fully elucidated. We hypothesised that bortezomib could influence osteoblastic differentiation via alteration of vitamin D signalling by blocking the proteasomal degradation of the vitamin D receptor (VDR). This is of clinical importance, as a high rate of vitamin D deficiency was reported in patients with myeloma. We performed cocultures of primary human mesenchymal stem cells (hMSCs) and human osteoblasts (hOBs) with myeloma cells, which resulted in an inhibition of the vitamin D-dependent differentiation of osteoblast precursors. Treatment with bortezomib led to a moderate increase in osteoblastic differentiation markers in hMSCs and hOBs. Importantly, this effect could be strikingly increased when vitamin D was added. Bortezomib led to enhanced nuclear VDR protein levels in hMSCs. Primary hMSCs transfected with a VDR luciferase reporter construct showed a strong increase in VDR signalling with bortezomib. In summary, stimulation of VDR signalling is a mechanism for the bortezomib-induced stimulation of osteoblastic differentiation. The data suggest that supplementation of vitamin D in patients with myeloma treated with bortezomib is crucial for optimal bone formation.

The effect of the combination of bisphosphonates and conventional chemotherapy on bone metabolic markers in multiple myeloma patients

PURPOSE

Urinary N-terminal telopeptides of type I collagen (uNTX), serum bone alkaline phosphatase (sBAP) have been acknowledged in observing bone metastases of solid tumors. The paper is designed to study the value of clinical application of uNTX and sBAP in the treatment of multiple myeloma (MM), as well as the action of bisphosphonates for osteolytic bone lesion.

METHODOLOGY

Thirty-three MM cases were treated with bisphosphonates (hereinafter called clodronate therapy group) and 20 MM cases were treated with simple chemotherapy (hereinafter called control group). uNTX and sBAP were tested during the courses of treatment three times (pretreatment, 3 months, and 6 months). uNTX was tested by enzyme-linked immunosorbent assay. sBAP was tested by chemiluminescence analysis. All the results were analyzed with t-test by using SPSS 11.0.

RESULTS

There were no significant differences between therapy and control groups: in uNTX (173.74 ± 14.55) and (129.79 ± 12.13) μg/l before treatment (P > 0.05). After 6 months there were significant differences between them: (85.71 ± 8.23) and (121.59 ± 12.43) μg/l (P < 0.05). And also there were significant differences among the courses in the therapy group. There were no significant differences between therapy and control groups in sBAP concentration: (4.78 ± 0.55) and (8.42 ± 1.32) μg/l before treatment (P > 0.05). After 6 months there were significant differences between them: (16.01 ± 0.52) and (9.62 ± 1.29) μg/l (P < 0.001). And also there were significant differences among the courses in the therapy group.

CONCLUSION

uNTX and sBAP were important to measure the situation of the osteolytic bone lesion in MM. Bisphosphonates can significantly reduce bone degradation and metabolism, improve the synthesis, which is valuable for the treatment of MM cases.

Increased T regulatory cells are associated with adverse clinical features and predict progression in multiple myeloma

Background

Regulatory T (Treg) cells play an important role in the maintenance of immune system homeostasis. Multiple myeloma (MM) is a plasma cell disorder frequently associated with impaired immune cell numbers and functions.

Methods

We analyzed Treg cells in peripheral blood (n = 207) and bone marrow (n = 202) of pre-malignant and malignant MM patients using flow cytometry. Treg cells and their subsets from MM patients and healthy volunteers were functionally evaluated for their suppressive property. A cohort of 25 patients was analyzed for lymphocytes, CD4 T cells and Treg cells before and after treatment with cyclophosphamide, thalidomide plus dexamethasone (CTD).

Results

We found elevated frequencies of Treg cells in newly diagnosed (P<0.01) and relapsed MM patients (P<0.0001) compared to healthy volunteers. Also, Treg subsets including naïve (P = 0.015) and activated (P = 0.036) Treg cells were significantly increased in MM patients compared to healthy volunteers. Functional studies showed that Treg cells and their subsets from both MM and healthy volunteers were similar in their inhibitory function. Significantly increased frequencies of Treg cells were found in MM patients with adverse clinical features such as hypercalcemia (>10 mg/dL), decreased normal plasma cell (≤5%) count and IgA myeloma subtype. We also showed that MM patients with ≥5% of Treg cells had inferior time to progression (TTP) (13 months vs. median not reached; P = 0.013). Furthermore, we demonstrated the prognostic value of Treg cells in prediction of TTP by Cox regression analysis (P = 0.045). CTD treatment significantly reduced frequencies of CD4 T cells (P = 0.001) and Treg cells (P = 0.018) but not Treg cells/CD4 T cells ratio compared to pre-treatment.

Conclusions

Our study showed immune deregulation in MM patients which is evidenced by elevated level of functionally active Treg cells and patients with increased Treg cells have higher risk of progression.

CCR1 blockade reduces tumor burden and osteolysis in vivo in a mouse model of myeloma bone disease

The chemokine CCL3/MIP-1α is a risk factor in the outcome of multiple myeloma (MM), particularly in the development of osteolytic bone disease. This chemokine, highly overexpressed by MM cells, can signal mainly through 2 receptors, CCR1 and CCR5, only 1 of which (CCR1) is responsive to CCL3 in human and mouse osteoclast precursors. CCR1 activation leads to the formation of osteolytic lesions and facilitates tumor growth. Here we show that formation of mature osteoclasts is blocked by the highly potent and selective CCR1 antagonist CCX721, an analog of the clinical compound CCX354. We also show that doses of CCX721 selected to completely inhibit CCR1 produce a profound decrease in tumor burden and osteolytic damage in the murine 5TGM1 model of MM bone disease. Similar effects were observed when the antagonist was used prophylactically or therapeutically, with comparable efficacy to that of zoledronic acid. 5TGM1 cells were shown to express minimal levels of CCR1 while secreting high levels of CCL3, suggesting that the therapeutic effects of CCX721 result from CCR1 inhibition on non-MM cells, most likely osteoclasts and osteoclast precursors. These results provide a strong rationale for further development of CCR1 antagonists for the treatment of MM and associated osteolytic bone disease.

The novel, orally bioavailable HSP90 inhibitor NVP-HSP990 induces cell cycle arrest and apoptosis in multiple myeloma cells and acts synergistically with melphalan by increased cleavage of caspases

Heat shock protein 90 (HSP90) binds and stabilizes numerous proteins and kinases essential for myeloma cell survival and proliferation. We and others have recently demonstrated that inhibition of HSP90 by small molecular mass inhibitors induces cell death in multiple myeloma (MM). However, some of the HSP90 inhibitors involved in early clinical trials have shown limited antitumor activity and unfavorable toxicity profiles. Here, we analyzed the effects of the novel, orally bioavailable HSP90 inhibitor NVP-HSP990 on MM cell proliferation and survival. The inhibitor led to a significant reduction in myeloma cell viability and induced G2 cell cycle arrest, degradation of caspase-8 and caspase-3, and induction of apoptosis. Inhibition of the HSP90 ATPase activity was accompanied by the degradation of MM phospho-Akt and phospho-ERK1/2 and upregulation of Hsp70. Exposure of MM cells to a combination of NVP-HSP990 and either melphalan or histone deacetylase (HDAC) inhibitors caused synergistic inhibition of viability, increased induction of apoptosis, and was able to overcome the primary resistance of the cell line RPMI-8226 to HSP90 inhibition. Combined incubation with melphalan and NVP-HSP990 led to synergistically increased cleavage of caspase-2, caspase-9, and caspase-3. These data demonstrate promising activity for NVP-HSP990 as single agent or combination treatment in MM and provide a rationale for clinical trials.

Maintaining bone health in patients with multiple myeloma: survivorship care plan of the International Myeloma Foundation Nurse Leadership Board

About 90% of individuals with multiple myeloma will develop osteolytic bone lesions from increased osteoclastic and decreased osteoblastic activity. Severe morbidities from pathologic fractures and other skeletal events can lead to poor circulation, blood clots, muscle wasting, compromised performance status, and overall poor survival. Supportive care targeting bone disease is an essential adjunct to antimyeloma therapy. In addition, the maintenance of bone health in patients with multiple myeloma can significantly improve quality of life. Oncology nurses and other healthcare providers play a central role in the management of bone disease and maintenance throughout the course of treatment. Safe administration of bisphosphonates, promotion of exercise, maintenance of adequate nutrition, vitamin and mineral supplementation, scheduled radiographic examinations, and monitoring of bone complications are among the important functions that oncology nurses and healthcare providers perform in clinical practice.

Therapeutic potential of CCR1 antagonists for multiple myeloma

The chemokine receptor CCR1 has been the target of intensive research for nearly two decades. Small-molecule antagonists were first reported in 1998 and, since then, many inhibitors for CCR1 have been brought forth. Yet, with all the money and time spent, to date, no small-molecule antagonists have successfully moved past Phase II clinical trials. With the current advancement of CCR1 antagonists by Bristol-Myers Squibb and Chemocentrix, there has been renewed interest. In this review, we present an overview of CCR1, its activating ligands, methods of signaling, and downstream response. We discuss studies that indicate CCR1 plays an important role in multiple myeloma and the underlying molecular mechanisms. Finally, we present an overview of the clinical and preclinical compounds for CCR1. We address individual structures, discuss their pharmacological précis, and summarize the published evidence to assess their value for use in multiple myeloma.

Brain-derived neurotrophic factor is a potential osteoclast stimulating factor in multiple myeloma

Multiple myeloma (MM) is characterized by accumulation of monoclonal plasma cells in the bone marrow and progression of lytic bone lesions. The mechanisms of enhanced bone resorption in patients with myeloma are not fully defined. We have previously identified the role of brain-derived neurotrophic factor (BDNF) in proliferation and migration of MM cells. In our study, we investigated whether BDNF was possibly involved in MM cell-induced osteolysis. We showed that BDNF was elevated in MM patients and the bone marrow plasma levels of BDNF positively correlated with extent of bone disease. In osteoclast formation assay, bone marrow plasma from patients with MM increased osteoclast formation and the effect was significantly blocked by neutralizing antibody to BDNF, suggesting a critical role for BDNF in osteoclast activation. Furthermore, the direct effects of recombinant BDNF on osteoclast formation and bone resorption support the potential role of BDNF in the MM bone disease. BDNF receptor TrkB was expressed by human osteoclast precursors and a Trk inhibitor K252a markedly inhibited osteoclast formation stimulated with BDNF, demonstrating that BDNF used TrkB for its effects on osteoclast. Finally, bone marrow plasma BDNF level positively correlated with macrophage inflammatory protein-1α and receptor activator of nuclear factor-κB ligand, two major osteoclast stimulatory factors in MM. These results support an important role for BDNF in the development of myeloma bone disease.

Osteoclast-gene expression profiling reveals osteoclast-derived CCR2 chemokines promoting myeloma cell migration

Multiple myeloma is characterized by the clonal expansion of malignant plasma cells (multiple myeloma cells [MMCs]), in the bone marrow. Osteolytic bone lesions are detected in 80% of patients because of increased osteoclastic bone resorption and reduced osteoblastic bone formation. MMCs are found closely associated with sites of increased bone resorption. Osteoclasts strongly support MMC survival in vitro. To further elucidate the mechanisms involved in osteoclast/MMC interaction, we have identified 552 genes overexpressed in osteoclasts compared with other bone marrow cell subpopulations. Osteoclasts express specifically genes coding for 4 CCR2-targeting chemokines and genes coding for MMC growth factors. An anti-CCR2 monoclonal antibody blocked osteoclast chemoattractant activity for MMC, and CCR2 chemokines are also MMC growth factors, promoting mitogen-activated protein kinase activation in MMC. An anti-insulin growth factor-1 receptor monoclonal antibody completely blocked the osteoclast-induced survival of MMC suppressing both osteoclast and MMC survival. Specific a proliferation-inducing ligand or IL-6 inhibitors partially blocked osteoclast-induced MMC survival. These data may explain why newly diagnosed patients whose MMC express high levels of CCR2 present numerous bone lesions. This study displays additional mechanisms involved in osteoclast/MMC interaction and suggests using CCR2 and/or insulin growth factor-1 targeting strategies to block this interaction and prevent drug resistance.

Pasteurella multocida toxin-stimulated osteoclast differentiation is B cell dependent

Pasteurella multocida is a Gram-negative bacillus that infects a number of wild and domestic animals, causing respiratory diseases. Toxigenic Pasteurella multocida strains produce a protein toxin (PMT) that leads to atrophic rhinitis in swine due to enhanced osteoclastogenesis and the inhibition of osteoblast function. We show that PMT-induced osteoclastogenesis is promoted by an as-yet-uncharacterized B-cell population. The toxin, however, is not acting at the level of hematopoietic stem cells, since purified CD117(+) cells from murine hematopoietic progenitor cells cultivated with PMT did not mature into osteoclasts. The early macrophages contained within this cell population (CD117(+)/CD11b(+)) did not further differentiate into osteoclasts but survived and were able to phagocytose. Within the CD117(-) population, however, we detected PMT-induced generation of a B220(+)/CD19(+) and B220(+)/IgM(+) B-cell population that was able to take up fluorescently labeled PMT. Using purified B-cell and macrophage populations, we show that these B cells are needed to efficiently generate osteoclasts from macrophages. Cells of the immune system are thought to affect osteoclast formation and function by secreting cytokines and growth factors. We show here that PMT-stimulated B cells produce elevated levels of the osteoclastogenic factors interleukin-1β (IL-1β), IL-6, tumor necrosis factor alpha, and receptor activator of nuclear factor receptor ligand (RANKL) compared to B cells generated through incubation with IL-7. These results suggest that the osteoclastic properties characteristic for PMT may result from a cross talk between bone cells and lymphoid cells and that B cells might be an important target of Pasteurella multocida.

BSc2118 is a novel proteasome inhibitor with activity against multiple myeloma

OBJECTIVES

The ubiquitin-proteasome system emerged as a new therapeutic target in cancer treatment. The purpose of this study was to elucidate the effects of the novel proteasome inhibitor BSc2118 on t(4;14) positive and negative multiple myeloma (MM) cells and normal peripheral blood mononuclear cells (PBMNC).

METHODS

Human MM cell lines OPM-2, RPMI-8226, and U266 and primary MM cells from bone marrow aspirates were exposed to BSc2118. Cytotoxicity levels were evaluated using the MTT-test. BSc2118-induced apoptosis was analyzed by annexin-V assay. Further methods used included proteasomal activity determination, cell cycle analysis, western blot, and transcription factor assays.

RESULTS

In OPM-2, RPMI-8226, U266 cell lines and primary MM cells, BSc2118 caused dose-dependent growth inhibitory effects. After 48 h, dose-dependent apoptosis occurred both in cell lines and primary myeloma cells irrespective of t(4;14). A significant G2-M cell cycle arrest occurred after 24 h. Furthermore, we observed a marked inhibition of intracellular proteasome activity, an increase in intracellular p21 levels, and an inhibition of NF-kappaB activation. The toxicity against PBMNC remained low, suggesting a broad therapeutic range of this agent.

CONCLUSION

Taken together, BSc2118 shows significant antimyeloma activity and may be considered as a promising agent in cancer drug development.

Advances in the understanding of myeloma bone disease and tumour growth

Advances in multiple myeloma support the notion that the associated bone disease, characterized by increased osteoclastogenesis and suppressed osteoblastogenesis, is both a consequence and necessity of tumour progression. Osteoblastogenesis is suppressed by secreted inhibitors and dysregulation of cell-surface 'coupling' factors on osteogenic cells. Osteoclastogenesis is increased as a consequence of osteoblast deactivation and of production of osteoclast-activating factors. Osteoclasts express soluble and cell-surface factors that stimulate myeloma growth, while osteoblasts produce bone-building factors that restrain growth of myeloma cells that are dependent on the microenvironment; detailed molecular mechanisms are discussed. Experimental and clinical findings indicate that pharmacological and experimental osteoblast-activating agents that effectively promote bone formation also reduce growth of myeloma cells within bone, seemingly by simultaneously stimulating osteoblastogenesis and restraining osteoclastogenesis. Unravelling mechanisms of myeloma bone disease expands horizons for developing novel interventions and also facilitates better understanding of the association between induction of osteolysis and disease progression.

Serum levels of total-RANKL in multiple myeloma

BACKGROUND

Receptor activator of nuclear factor-kappaB ligand (RANKL) plays a key role in osteoclast activation in myeloma bone disease. The increased expression of RANKL in the bone marrow microenvironment was demonstrated in several studies, but there are only rare data on circulating RANKL levels in patients with multiple myeloma (MM).

PATIENTS AND METHODS

In the current study, we investigated the clinical significance of serum RANKL levels, using an enzyme-linked immunosorbent assay test that detects both free and osteoprotegerin (OPG)-bound RANKL (total-RANKL, tRANKL) in patients with newly diagnosed MM (n = 93) and monoclonal gammopathy of undetermined significance (MGUS; n = 20) compared with healthy controls (n = 20).

RESULTS

Circulating serum tRANKL was significantly elevated in patients with MM compared with controls (P < .001) or MGUS (P < .001). Furthermore, tRANKL levels were higher in smoldering MM versus MGUS (P = .031) and in symptomatic versus smoldering MM (P < .001). Serum tRANKL increased parallel to International Staging System stages I to III (P = .004) and correlated with the presence of lytic bone lesions (P < .001). Total-RANKL was a prognostic factor for overall survival in symptomatic MM (P = .043). A significantly longer progression-free survival was observed in patients with a > 50% decrease in tRANKL levels after 3 months of combined chemotherapy and bisphosphonate treatment.

CONCLUSION

Our study demonstrates for the first time that serum tRANKL reflects advanced disease, lytic bone destruction, and poor prognosis in MM.

Synergistic action of the novel HSP90 inhibitor NVP-AUY922 with histone deacetylase inhibitors, melphalan, or doxorubicin in multiple myeloma

Heat shock protein 90 (HSP90) is a promising target for tumor therapy. The novel HSP90 inhibitor NVP-AUY922 has preclinical activity in multiple myeloma, however, little is known about effective combination partners to design clinical studies. Multiple myeloma cell lines, OPM-2, RPMI-8226, U-266, LP-1, MM1.S, and primary myeloma cells were exposed to NVP-AUY922 and one of the combination partners histone deacetylase inhibitor NVP-LBH589, suberoylanilide hydroxamic acid (SAHA), melphalan, or doxorubicin, either simultaneously or in sequential patterns. Effects on cell proliferation and apoptosis were determined. Synergistic effects were evaluated using the method of Chou and Talalay. Combined sequential incubation with NVP-AUY922 and SAHA showed that best synergistic effects were achieved with 24 h preincubation with SAHA followed by another 48 h of combination treatment. Combination of NVP-AUY922 with SAHA, NVP-LBH589, melphalan, or doxorubicin resulted in synergistic inhibition of viability, with strong synergy (combination index < 0.3) in the case of melphalan. Importantly, resistance of the RPMI-8226 cell line and relative resistance of some primary myeloma cells against NVP-AUY922 could be overcome by combination treatment. These data show impressive synergistic action of the novel HSP90 inhibitor NVP-AUY922 with melphalan, doxorubicin, NVP-LBH589, and SAHA in multiple myeloma and build the frame work for clinical trials.

Myeloma cell-induced disruption of bone remodelling compartments leads to osteolytic lesions and generation of osteoclast-myeloma hybrid cells

Osteolytic lesions are a hallmark of multiple myeloma. They are due to the hyperactivity of bone resorbing osteoclasts and hypoactivity of bone forming osteoblasts, in response to neighbouring myeloma cells. This study identified a structure that deeply affects this response, because of its impact on the physical organisation of the myeloma cell microenvironment. The proximity between myeloma cells and osteoclasts or osteoblasts was shown to be conditioned by the recently discovered layer of flat cells that separates the osteoclasts and osteoblasts from the bone marrow, by forming a canopy over bone remodelling compartment (BRC). These canopies are frequently disrupted in myeloma, and this disruption correlates with increased proximity and density of myeloma cells. In vitro evidence indicates that this disruption may be due to direct contact between myeloma and BRC canopy cells. Importantly, this disruption and increased proximity and density of myeloma cells coincides with key myeloma-induced bone events, such as osteolytic lesions, impaired bone formation despite increased bone resorption, and fusion of myeloma cells with osteoclasts thereby forming myeloma-osteoclast hybrid cells. These findings strongly support a critical role of BRC canopies in myeloma-induced bone disease. BRC canopies could therefore be considered as a new therapeutic target.