Myeloma bone disease and treatment options

The EGFL7-ITGB3-KLF2 axis enhances survival of multiple myeloma in preclinical models

Angiogenic factors play a key role in multiple myeloma (MM) growth, relapse, and drug resistance. Here we show that malignant plasma cells (cell lines and patient-derived MM cells) express angiocrine factor EGF like-7 (EGFL7) mRNA and protein. MM cells both produced EGFL7 and expressed the functional EGFL7 receptor integrin β 3 (ITGB3), resulting in ITGB3 phosphorylation and focal adhesion kinase activation. Overexpression of ITGB3 or EGFL7 enhanced MM cell adhesion and proliferation. Intriguingly, ITGB3 overexpression upregulated the transcription factor Krüppel-like factor 2 (KLF2), which further enhanced EGFL7 transcription in MM cells, thereby establishing an EGFL7-ITGB3-KLF2-EGFL7 amplification loop that supports MM cell survival and proliferation. EGFL7 expression was found in certain plasma cells of patients with refractory MM and of patients at primary diagnosis. NOD.CB17-Prkdc/J mice transplanted with MM cells showed elevated human plasma EGFL7 levels. EGFL7 knockdown in patient-derived MM cells and treatment with neutralizing antibodies against EGFL7 inhibited MM cell growth in vitro and in vivo. We demonstrate that the standard-of-care MM drug bortezomib upregulates EGFL7, ITGB3, and KLF2 expression in MM cells. Inhibition of EGFL7 signaling in synergy with BTZ may provide a novel strategy for inhibiting MM cell proliferation.

Role of intravenous dosage regimens of bisphosphonates in relation to other aetiological factors in the development of osteonecrosis of the jaws in patients with myeloma

The aim of this case-control study was to identify possible explanatory risk factors for the development of bisphosphonate-related osteonecrosis of the jaws (BRONJ) by estimating the effects of intravenous dosage regimens of bisphosphonates, coexisting diseases, and other drugs on 201 patients with multiple myeloma, with or without BRONJ. We compared sex, treatment with bisphosphonates, incidence of diabetes, and the taking of drugs such as corticosteroids and chemotherapy in patients who had BRONJ (n=44) and patients who did not (n=157). Among the bisphosphonates given intravenously zoledronic acid showed a stronger correlation with BRONJ than pamidronic acid. The risk of developing BRONJ increased dramatically at cumulative intravenous doses of more than 78 mg of zoledronic acid or 600 mg of pamidronic acid, which corresponds to treatment for 18 months or longer. Diabetes mellitus correlated significantly with the development of BRONJ (p=0.01) while there was no correlation with sex, simultaneous treatment with corticosteroids, or chemotherapy. In conclusion, treatment with zoledronic acid, high doses of pamidronic acid, and the coexistence of diabetes mellitus seem to be associated with the development of BRONJ.

Mathematical modelling of the pathogenesis of multiple myeloma-induced bone disease

Multiple myeloma (MM) is the second most common haematological malignancy and results in destructive bone lesions. The interaction between MM cells and the bone microenvironment plays an important role in the development of the tumour cells and MM-induced bone disease and forms a 'vicious cycle' of tumour development and bone destruction, intensified by suppression of osteoblast activity and promotion of osteoclast activity. In this paper, a mathematical model is proposed to simulate how the interaction between MM cells and the bone microenvironment facilitates the development of the tumour cells and the resultant bone destruction. It includes both the roles of inhibited osteoblast activity and stimulated osteoclast activity. The model is able to mimic the temporal variation of bone cell concentrations and resultant bone volume after the invasion and then removal of the tumour cells and explains why MM-induced bone lesions rarely heal even after the complete removal of MM cells. The behaviour of the model compares well with published experimental data. The model serves as a first step to understand the development of MM-induced bone disease and could be applied further to evaluate the current therapies against MM-induced bone disease and even suggests new potential therapeutic targets.

In silico investigations of potential anabolic treatments in multiple myeloma-induced bone disease

No anabolic drugs are currently approved to treat multiple myeloma (MM)-induced bone disease and the anti-MM agent bortezomib exhibits the anabolic effects in the clinic. In this study, we focus on investigating potential anabolic treatments of MM-induced bone disease using our previously proposed MM-bone model, with the goal for clarifying the underlying molecular/cellular mechanisms. Firstly, a variety of virtual drug treatments are explored by the parametric study to clarify the anabolic-related molecular/cellular mechanisms. The real drug (i.e., bortezomib) treatments are further examined by developing an integrated model with bortezomib to validate the clarified anabolic-related molecular/cellular mechanisms. The simulated responses to the bortezomib treatments that are validated by the clinical data are consistent with the simulated responses to the virtual drug treatments. Our study clarifies that the anabolic effects in the treatment of MM-induced bone disease are associated with promoting the differentiation of bone marrow stromal cells (BMSC) and inhibiting the apoptosis of active osteoblasts, while promoting the differentiation of osteoblast precursors is instead suggested to be associated with the anti-catabolic effects. Compared with the individual anabolic therapies, the anabolic therapies that promote the differentiation of BMSC in combination with the anti-MM/anti-catabolic therapies are found to induce a greater increase in the bone volume, while the anabolic therapies that inhibit the apoptosis of active osteoblasts in combination with the anti-MM/anti-catabolic therapies induce a lower increase in the bone volume. The simulations also suggest that the direct inhibition of bortezomib on the osteoclast activity is probably a redundant mechanism.

Trace determination of lenalidomide in plasma by non-extractive HPLC procedures with fluorescence detection after pre-column derivatization with fluorescamine

BACKGROUND

Lenalidomide (LND) is a new potent drug used for treatment of multiple myeloma. For its pharmacokinetic studies and therapeutic monitoring, a proper analytical method was required.

RESULTS

In this study, a non extractive and simple pre-column derivatization procedures have been proposed, for the for trace determination of lenalidomide (LND) in human plasma by HPLC with fluorescence detection. Plasma samples were treated with acetonitrile for protein precipitation then treated with copper acetate to form stable complexes with the biogenic amines and mask their interference with the derivatization reaction of LND. Treated plasma samples containing LND was derivatized with fluorescamine (FLC) in aqueous media at ambient temperature. Separation of the derivatized LND was performed on Hypersil BDS C18 column (250 × 4.6 mm, 5 μm particle size) using a mobile phase consisting of phosphate buffer (pH 4):methanol: tetrahydrofuran (70:10:20, v/v) at a flow rate of 1.0 mL/min. The derivatized samples were monitored at an emission wavelength of 495 nm after excitation at a wavelength of 382 nm. Under the optimum chromatographic conditions, a linear relationship with good correlation coefficient (r = 0.9997, n = 9) was found between the peak area and LND concentrations in the range of 2-100 ng/mL. The limits of detection and quantitation were 0.8 and 2.30 ng/mL, respectively. The intra- and inter-assay precisions were satisfactory and the accuracy of the method was proved. The recovery of LND from the spiked human plasma was 99.30 ± 2.88.

CONCLUSIONS

The proposed method had high throughput as the analysis involved simple sample pre-treatment procedure and a relatively short run-time (< 15 min). The results demonstrated that the method would have a great value when it is applied in the therapeutic monitoring and pharmacokinetic studies for LND.

In silico investigations of the anti-catabolic effects of pamidronate and denosumab on multiple myeloma-induced bone disease

It is unclear whether the new anti-catabolic agent denosumab represents a viable alternative to the widely used anti-catabolic agent pamidronate in the treatment of Multiple Myeloma (MM)-induced bone disease. This lack of clarity primarily stems from the lack of sufficient clinical investigations, which are costly and time consuming. However, in silico investigations require less time and expense, suggesting that they may be a useful complement to traditional clinical investigations. In this paper, we aim to (i) develop integrated computational models that are suitable for investigating the effects of pamidronate and denosumab on MM-induced bone disease and (ii) evaluate the responses to pamidronate and denosumab treatments using these integrated models. To achieve these goals, pharmacokinetic models of pamidronate and denosumab are first developed and then calibrated and validated using different clinical datasets. Next, the integrated computational models are developed by incorporating the simulated transient concentrations of pamidronate and denosumab and simulations of their actions on the MM-bone compartment into the previously proposed MM-bone model. These integrated models are further calibrated and validated by different clinical datasets so that they are suitable to be applied to investigate the responses to the pamidronate and denosumab treatments. Finally, these responses are evaluated by quantifying the bone volume, bone turnover, and MM-cell density. This evaluation identifies four denosumab regimes that potentially produce an overall improved bone-related response compared with the recommended pamidronate regime. This in silico investigation supports the idea that denosumab represents an appropriate alternative to pamidronate in the treatment of MM-induced bone disease.

Unusual manifestation of a multiple myeloma in the hyoid bone

The most common manifestation of plasma cell neoplasms is multiple myeloma. Solitary and localized tumours in the form of solitary plasmacytoma of the bone or extramedullary plasmacytoma are rare. In the late stages of multiple myeloma, bulky bone tumour infiltrates may be found which may be the primary clinical manifestation of the previously unknown malignancy. We report a case of a hyoid bone tumour with extramedullary plasma cell infiltrates in the oropharynx in multiple myeloma.

Computational modeling of interactions between multiple myeloma and the bone microenvironment

Multiple Myeloma (MM) is a B-cell malignancy that is characterized by osteolytic bone lesions. It has been postulated that positive feedback loops in the interactions between MM cells and the bone microenvironment form reinforcing ‘vicious cycles’, resulting in more bone resorption and MM cell population growth in the bone microenvironment. Despite many identified MM-bone interactions, the combined effect of these interactions and their relative importance are unknown. In this paper, we develop a computational model of MM-bone interactions and clarify whether the intercellular signaling mechanisms implemented in this model appropriately drive MM disease progression. This new computational model is based on the previous bone remodeling model of Pivonka et al. [1], and explicitly considers IL-6 and MM-BMSC (bone marrow stromal cell) adhesion related pathways, leading to formation of two positive feedback cycles in this model. The progression of MM disease is simulated numerically, from normal bone physiology to a well established MM disease state. Our simulations are consistent with known behaviors and data reported for both normal bone physiology and for MM disease. The model results suggest that the two positive feedback cycles identified for this model are sufficient to jointly drive the MM disease progression. Furthermore, quantitative analysis performed on the two positive feedback cycles clarifies the relative importance of the two positive feedback cycles, and identifies the dominant processes that govern the behavior of the two positive feedback cycles. Using our proposed quantitative criteria, we identify which of the positive feedback cycles in this model may be considered to be ‘vicious cycles’. Finally, key points at which to block the positive feedback cycles in MM-bone interactions are identified, suggesting potential drug targets.

Novel approaches in the management of myeloma-related skeletal complications

Patients with multiple myeloma (MM) experience pathologic fractures, bone pain, hypercalcemia, neurologic symptoms, and renal insufficiency with substantial morbidity and mortality. Bisphosphonates have been used successfully for the management of MM-related bone disease. Increased incidence of osteonecrosis of the jaw has been observed in patients with cancer receiving bisphosphonate therapy. Recent advances in the pathobiology of MM-related bone disease and other cancer-related bone metastases have led to the identification of novel therapeutic targets, such as receptor activator of nuclear factor-kappaB (RANK); its ligand (RANKL); and a decoy receptor, osteoprotegerin, for the development of potential targeted agents. Initials studies have demonstrated that targeting RANK/ RANKL signaling with the fully human monoclonal antibody denosumab prevented skeletal complications in patients with MM and other cancers with bone metastases. Ongoing studies evaluating the clinical utility of denosumab in cancer- related bone destruction have been discussed. In addition, several potential targets, such as macrophage inflammatory protein-1alpha, chemokine receptors 1 and 5, interleukin-3, and Wnt signaling, are b riefly described.

Expression and prognostic relevance of MAGE-C1/CT7 and MAGE-C2/CT10 in osteolytic lesions of patients with multiple myeloma

Cancer-testis (CT) antigens are promising targets for antigen-specific therapy of multiple myeloma (MM). Osteolytic lesions represent the most common clinical manifestation of myeloma and it is possible that osseous myeloma lesions differ from bone-infiltrating tumor cells with regard to the extent of CT antigen expression based on the epigenetic regulation of these genes. We, therefore, performed the first analysis of CT antigen expression in osteolytic lesions of myeloma patients to further define the diagnostic, prognostic, and therapeutic value of these proteins. Lytic bone samples were obtained from MM patients during surgical interventions and a tissue microarray was constructed. 105 bone samples and 24 bone marrow biopsies were stained immunohistochemically with antibodies against CT antigens MAGE-C1/CT7 and MAGE-C2/CT10 and Ki-67. MAGE-C1/CT7 and MAGE-C2/CT10 were frequently expressed in osteolytic lesions (46% and 54%) and bone marrow (75% and 54%). Expression of MAGE-C1/CT7 was significantly more frequent in patients with advanced stage of disease (p=0.023) and with a chromosomal deletion 17p13 (p53) (p=0.047). Samples with more than 75% MAGE-C1/CT7 expressing myeloma cells showed a higher proliferative rate (indicated by the expression of Ki67) than those with less than 25% MAGE-C1/CT7 expressing cells (p=0.011). Moreover, a content of ≥50% MAGE-C1/CT7 expressing myeloma cells in a sample was associated with reduced overall survival (p=0.013). Our results, therefore, suggest that expression of MAGE-C1/CT7 and MAGE-C2/CT10 in osteolytic lesions of myeloma patients can be used for diagnostic, prognostic, as well as immunotherapeutic purposes.

Breaking tolerance in a mouse model of multiple myeloma by chemoimmunotherapy

A unique mouse model of multiple myeloma (MM), namely 5T2MM-bearing mouse, was useful for elucidating the pathophysiological mechanisms underlying the disease. Increased accumulation of suppressive CD4(+)CD25(High)Foxp3(+) regulatory T cells (Tregs) was observed in the thymus and lymphoid peripheral organs during disease progression. Adoptive transfer of Tregs, but not other thymocytes, from 5T2MM-bearing mice led to increased progression of disease manifestations in young syngeneic mice. Depletion of Tregs, a proposed strategy in cancer immunotherapy, was tested using cyclophosphamide (CYC), an alkylating agent with selective cytotoxicity. Both low- and high-dose CYC, administered to sick mice with hind limb paralysis, caused the paralysis to disappear, the plasma tumor cells in the bone marrow (BM) cavity to be replaced by normal cell populations, and the survival of the mice to be significantly prolonged. Low-dose CYC, which selectively depletes Tregs, decreased MM incidence, in contrast to high-dose CYC, which was generally cytotoxic, and did not reduce MM incidence. In contrast, low-dose CYC induced Tregs to become susceptible to apoptosis by downregulating Bcl-xL and CTLA-4 in these cells, and by decreasing the production of IL-2 by effector CD4 cells. This treatment consequently triggered the recovery of IFN-gamma-producing natural killer T cells and the maturation of dendritic cells. Transient gradual depletion of Tregs in low-dose CYC-treated 5T2MM mice was maintained beyond 45 days. Thus, less frequent injections of low-dose CYC enabled us to recruit compatible immune-derived cells that would reduce tumor load and delay or prevent tumor recurrence, hence breaking immune tolerance toward MM tumor cells.

153Sm: its use in multiple myeloma and report of a clinical experience

BACKGROUND

In the past years the bone seeking radiopharmaceutical samarium lexidronam ((153)Sm-EDTMP) has been increasingly used alone or in conjunction with chemotherapy and/or bisphosphonates for the treatment of painful bone metastasis.

OBJECTIVE

Its use has been explored in different solid tumours. In this report we explore its interesting characteristics and describe our experience in multiple myeloma (MM).

METHODS

(153)Sm-EDTMP has an affinity for bone and concentrates in areas of bone turnover. It decays as a therapeutic beta-emission and at the same time as gamma-photon that can be used for tracking its concentration with bone scan imaging. Ten patients with symptomatic MM were treated to achieve pain control.

RESULTS

Encouraging results were obtained in MM patients. The use of this radioisotope could be largely improved.

The biomechanics of vertebroplasty in multiple myeloma and metastatic bladder cancer: a preliminary cadaveric investigation

Object

The vertebral column is the most common site for secondary bone metastases and lesions arising from hematological malignancies such as multiple myeloma (MM). These infiltrations can be lytic in nature and cause severe weakening of the vertebral body, an increased risk of fracture, and spinal cord compression leading to neurological deficit. Qualitatively it is apparent that increasing infiltration of these lytic lesions will have a deleterious effect on the mechanical behavior of the vertebrae. However, there is little quantitative information about the relationship between tumor deposits and the impact on the mechanical behavior of the vertebrae. In addition, there have been limited biomechanical assessments of the use of vertebroplasty in the management of these malignancies. The purpose of this preliminary study was to evaluate the mechanical behavior of lesion-infiltrated vertebrae from 2 malignant cancers and to investigate the effectiveness of vertebroplasty with and without tumor debulking.

Methods

Individual vertebrae from 2 donor spines—one with MM and another with bone metastases secondary to bladder cancer—were fractured under an eccentric flexion load, from which failure strength and stiffness were derived. Alternate vertebrae defined by spinal level were assigned to 2 groups: Group 1 involved removal of lesion material with Coblation (ArthroCare Corp.) preceding vertebroplasty; Group 2 received no Coblation prior to augmentation. All vertebrae were fractured postaugmentation under the same loading protocol. Micro-CT assessments were undertaken to investigate vertebral morphology, fracture patterns, and cement distribution.

Results

Multiple myeloma involvement was characterized by several small lesions, severe bone degradation, and multiple areas of vertebral shell compromise. In contrast, large focal lesions were present in the vertebrae with metastatic bladder cancer, and the shell generally remained intact. The mean initial failure strength of the vertebrae with metastases secondary to MM was significantly lower than in vertebrae with bone metastases secondary to bladder cancer (Load = 950 ± 300 N vs 2200 ± 750 N, p < 0.0001). A significant improvement in relative fracture strength was found postaugmentation for both lesion types (1.4 ± 0.5, p < 0.001). Coblation provided a marginally significant increase in the same parameter postaugmentation (p = 0.08) and qualitatively improved the ease of injection and guidance of cement.

Conclusions

In the vertebral column, metastatic lesions secondary to bladder cancer and MM showed variations in the pattern of infiltration, both of which led to significant reductions in fracture strength. Account should be taken of these differences to optimize the vertebroplasty intervention in terms of the cement formulation, delivery, and any additional surgical procedure.

Increased regulatory versus effector T cell development is associated with thymus atrophy in mouse models of multiple myeloma

CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) play a central role in cancer tolerance. However, mechanisms leading to their accumulation in cancer remain unknown. Although the thymus is the main site of Treg development, thymic contribution to Treg expansion in cancer has not been directly examined. Herein, we used two murine models of multiple myeloma (MM), 5T2 MM and 5T33 MM, to examine Treg accumulation in peripheral lymphoid organs, including spleen, lymph nodes, bone marrow, and blood, and to explore thymic Treg development during malignancy. We found that peripheral ratios of suppressive-functional Tregs increased in both models of MM-inflicted mice. We found that thymic ratios of Treg development in MM increased, in strong association with thymus atrophy and altered developmental processes in the thymus. The CD4(+)CD8(+) double-positive population, normally the largest thymocyte subset, is significantly decreased, whereas the CD4(-)CD8(-) double-negative population is increased. Administration of thymocytes from MM-inflicted mice compared with control thymocytes resulted in increased progression of the disease, and this effect was shown to be mediated by Tregs in the thymus of MM-inflicted mice. Our data suggest that increased ratios of Treg development in the thymus may contribute to disease progression in MM-inflicted mice.

An osteoclast-targeting agent for imaging and therapy of bone metastasis

A hybrid compound (DO3A-BP) featuring a radiometal bifunctional chelator (1,4,7,10-tetraazacyclotetradecane-N,N',N'',N'''-tetraacetic acid, DOTA) and an osteoclast-targeting moiety (bisphosphonate) was designed and synthesized. The (111)In-labeled complex of DO3A-BP showed significantly elevated uptake in osteoclasts compared to the undifferentiated adherent bone marrow derived cells. Biodistribution studies revealed a favorable tissue distribution profile in normal mice with high bone uptake and long retention, and low or negligible accumulation in non-target organs.

Zoledronic acid : a review of its use in the management of bone metastases of malignancy

Zoledronic acid (Zometa), a third-generation amino-bisphosphonate, has been approved in the US, the EU and many other countries worldwide for the prevention of skeletal-related events in patients with bone metastases of malignancy. In several well designed trials, zoledronic acid 4 mg administered as a 15-minute infusion every 3-4 weeks was effective in reducing the occurrence of skeletal complications in patients with bone metastases secondary to multiple myeloma, breast cancer or prostate cancer. Zoledronic acid was as effective as pamidronic acid in reducing the occurrence of skeletal complications in patients with multiple myeloma or breast cancer. In patients with solid tumours other than breast or prostate cancer, zoledronic acid did not show significant clinical benefit over placebo in terms of the primary endpoint; however, some benefit of therapy in terms of secondary endpoints was observed with zoledronic acid relative to placebo. Its efficacy in a broad range of tumours and short infusion time (15 minutes) are an advantage over other available bisphosphonates. Modelled pharmacoeconomic analyses in patients with breast cancer suggested that zoledronic acid therapy is cost effective relative to no therapy with regard to the cost per quality-adjusted life-year (QALY) gained; however, results were mixed when zoledronic acid was compared with other commonly used bisphosphonates. Zoledronic acid is generally well tolerated; the risk of osteonecrosis of the jaw may be minimized by adhering to recommendations regarding dental therapy. Additional efficacy and economic data are required to definitively position zoledronic acid with respect to other bisphosphonates. Nevertheless, available clinical data indicate that zoledronic acid is an effective treatment option for the management of bone metastases of malignancy.

Effect of pathologic fractures on survival in multiple myeloma patients: a case control study

BACKGROUND

Multiple Myeloma (MM) is a B cell neoplasm characterized by the clonal proliferation of plasma cells. Skeletal complications are found in up to 80% of myeloma patients at presentation and are major cause of morbidity.

METHODS

49 patients were enrolled with MM admitted to Black Sea Technical University Hospital between 2002-2005. Pathologic fractures (PFs) were determined and the patients with or without PF were followed up minimum 3 years for survival analysis.

RESULTS

PF was observed in 24 patients (49%) and not observed in 25 patients (51%). The risk of death was increased in the patients with PF compared with patients who had no fractures. While overall survival was 17.6 months in the patients with PFs, it was 57.3 months in the patients with no PFs.

CONCLUSION

These findings suggest that PFs may induce reduced survival and increased mortality in the MM patients, however, larger sample size is essential to draw clearer conclusions added to these data.

[Multiple myeloma]

Multiple myeloma is the second most common hematological malignancy. It is defined by the presence of monoclonal plasma cells capable to produce a monoclonal paraprotein causing clinical abnormalities such as anemia, renal insufficiency, hypercalcemia, or bone lesions. New chromosomal or molecular abnormalities have been identified allowing a better management. Multiple myeloma is treatable and, although it remains incurable, the patient prognosis and quality of life has notably improved, so it is not rare to see series with a median survival longer than 5 years. Even more, it is possible by now to expect improvements respect to the standard autologous stem cell transplantation. This must be attributed to the emergence of a number of new therapies entering clinical practice over the last 6 years: thalidomide (Thalidomid Pharmion, Boulder, CO, USA), lenalidomide (Revlimid, Celgene Corporation, Summit, NJ, USA) and bortezomib (Velcade, Janssen Pharmaceutica N.V., Belgium). Finally, we also will review the current clinical experience in supportive therapy, which has also contributed to the patient outcome improvement with approaches such as: new indications for dialysis, use of erythropoietin receptor stimulating agents and bisphosphonates, and new surgical therapies such as vertebroplastia and kyphoplastia.

The role of the bone microenvironment in the pathophysiology and therapeutic management of multiple myeloma: interplay of growth factors, their receptors and stromal interactions

The close relationship between the biological behaviour of malignant cells and the local microenvironment where they reside is a feature of diverse neoplasias. Multiple myeloma (MM) is considered a main disease model for the study of such interactions and the mechanisms that can lead to bone-related clinical complications, as well as the role of these interactions in attenuating the activity of conventional anti-MM therapeutics, such as dexamethasone and cytotoxic chemotherapeutics. This review focuses on recent progress in the study of interactions of MM cells with their local microenvironment. Major emphasis is placed on how bone marrow stromal cells (BMSCs) and other normal constituents of the bone marrow milieu promote, through cell adhesion- and cytokine-mediated mechanisms, the ability of MM cells to resist conventional anti-MM therapies. The review also addresses ongoing research into these mechanisms, which has already provided several new molecular targets and corresponding therapeutic strategies, such as the proteasome inhibitor bortezomib and thalidomide derivatives (e.g. lenalidomide), for the management of myeloma.