Zoledronic acid affects over-angiogenic phenotype of endothelial cells in patients with multiple myeloma

Anti-Angiogenic Activity of Drugs in Multiple Myeloma

Angiogenesis represents a pivotal hallmark of multiple myeloma (MM) that correlates to patients’ prognosis, overall survival, and drug resistance. Hence, several anti-angiogenic drugs that directly target angiogenic cytokines (i.e., monoclonal antibodies, recombinant molecules) or their cognate receptors (i.e., tyrosine kinase inhibitors) have been developed. Additionally, many standard antimyeloma drugs currently used in clinical practice (i.e., immunomodulatory drugs, bisphosphonates, proteasome inhibitors, alkylating agents, glucocorticoids) show anti-angiogenic effects further supporting the importance of inhibiting angiogenesis from potentiating the antimyeloma activity. Here, we review the most important anti-angiogenic therapies used for the management of MM patients with a particular focus on their pharmacological profile and on their anti-angiogenic effect in vitro and in vivo. Despite the promising perspective, the direct targeting of angiogenic cytokines/receptors did not show a great efficacy in MM patients, suggesting the need to a deeper knowledge of the BM angiogenic niche for the design of novel multi-targeting anti-angiogenic therapies.

MRONJ of the Mandible—From Decortication to a Complex Jaw Reconstruction Using a CAD/CAM-Guided Bilateral Scapula Flap

Medication-related osteonecrosis of the jaw (MRONJ) has been an integral part of the maxillofacial patient population for some time. The therapeutic concept ranges from conservative approaches over less extended decortications to major jaw resections, which can result in a considerable loss of quality of life. Based on three case reports, this paper presents the long-term history of patients with MRONJ of the mandible, whose disease ultimately resulted in partial or total mandibular resection and subsequent multisegmental reconstruction using a microvascular anastomosed bone flap. Furthermore, a suitable alternative for complex mandibular reconstruction is demonstrated when using a free fibula flap is not possible. The options are limited, particularly when multisegmental restoration of mandibular continuity is required. One case presents a mandible reconstruction using a CAD/CAM-guided bilateral scapular free flap (CAD/CAM = Computer-Aided Design and Manufacturing), which has not been described for this purpose before. Due to the complexity, computer-assisted surgery and patient-specific implants seem reasonable, which is why a special focus was applied to this topic.

Pathways of Angiogenic and Inflammatory Cytokines in Multiple Myeloma: Role in Plasma Cell Clonal Expansion and Drug Resistance

Multiple myeloma (MM) is the second most common hematological malignancy, and despite the introduction of innovative therapies, remains an incurable disease. Identifying early and minimally or non-invasive biomarkers for predicting clinical outcomes and therapeutic responses is an active field of investigation. Malignant plasma cells (PCs) reside in the bone marrow (BM) microenvironment (BMME) which comprises cells (e.g., tumour, immune, stromal cells), components of the extracellular matrix (ECM) and vesicular and non-vesicular (soluble) molecules, all factors that support PCs’ survival and proliferation. The interaction between PCs and BM stromal cells (BMSCs), a hallmark of MM progression, is based not only on intercellular interactions but also on autocrine and paracrine circuits mediated by soluble or vesicular components. In fact, PCs and BMSCs secrete various cytokines, including angiogenic cytokines, essential for the formation of specialized niches called “osteoblastic and vascular niches”, thus supporting neovascularization and bone disease, vital processes that modulate the pathophysiological PCs–BMME interactions, and ultimately promoting disease progression. Here, we aim to discuss the roles of cytokines and growth factors in pathogenetic pathways in MM and as prognostic and predictive biomarkers. We also discuss the potential of targeted drugs that simultaneously block PCs’ proliferation and survival, PCs–BMSCs interactions and BMSCs activity, which may represent the future goal of MM therapy.

Patient-Derived Multiple Myeloma 3D Models for Personalized Medicine-Are We There Yet?

Despite the wide variety of existing therapies, multiple myeloma (MM) remains a disease with dismal prognosis. Choosing the right treatment for each patient remains one of the major challenges. A new approach being explored is the use of ex vivo models for personalized medicine. Two-dimensional culture or animal models often fail to predict clinical outcomes. Three-dimensional ex vivo models using patients' bone marrow (BM) cells may better reproduce the complexity and heterogeneity of the BM microenvironment. Here, we review the strengths and limitations of currently existing patient-derived ex vivo three-dimensional MM models. We analyze their biochemical and biophysical properties, molecular and cellular characteristics, as well as their potential for drug testing and identification of disease biomarkers. Furthermore, we discuss the remaining challenges and give some insight on how to achieve a more biomimetic and accurate MM BM model. Overall, there is still a need for standardized culture methods and refined readout techniques. Including both myeloma and other cells of the BM microenvironment in a simple and reproducible three-dimensional scaffold is the key to faithfully mapping and examining the relationship between these players in MM. This will allow a patient-personalized profile, providing a powerful tool for clinical and research applications.

A Journey through the Inter-Cellular Interactions in the Bone Marrow in Multiple Myeloma: Implications for the Next Generation of Treatments

Tumors are composed of a plethora of extracellular matrix, tumor and non-tumor cells that form a tumor microenvironment (TME) that nurtures the tumor cells and creates a favorable environment where tumor cells grow and proliferate. In multiple myeloma (MM), the TME is the bone marrow (BM). Non-tumor cells can belong either to the non-hematological compartment that secretes soluble mediators to create a favorable environment for MM cells to grow, or to the immune cell compartment that perform an anti-MM activity in healthy conditions. Indeed, marrow-infiltrating lymphocytes (MILs) are associated with a good prognosis in MM patients and have served as the basis for developing different immunotherapy strategies. However, MM cells and other cells in the BM can polarize their phenotype and activity, creating an immunosuppressive environment where immune cells do not perform their cytotoxic activity properly, promoting tumor progression. Understanding cell-cell interactions in the BM and their impact on MM proliferation and the performance of tumor surveillance will help in designing efficient anti-MM therapies. Here, we take a journey through the BM, describing the interactions of MM cells with cells of the non-hematological and hematological compartment to highlight their impact on MM progression and the development of novel MM treatments.

Bone targeted new zoledronate derivative: design, synthesis, 99mTc-coupling, in-silico study and preclinical evaluation for promising osteosarcoma therapy

Background: Zoledronate suppresses human sarcomas by blocking the formation of geranylgeranyl diphosphate (GGPP) via inhibiting GGPP synthase.Objectives: Designing of new derivative of dronic acid (1-hydroxy-2-(4-nitro-1H-imidazol-1-yl)ethan-1,1-diyl)bis phosphonic acid), structurally related to zoledronate to be used for osteosarcoma therapy.Methods: 1-hydroxy-2-(4-nitro-1H-imidazol-1-yl)ethan-1,1-diyl)bis(phosphonic acid) was synthesized in one pot reaction with a yield of 65 ± 4%. The synthesized nitro-zoledronate compound was successfully radiolabeled with 99mTc with a radiochemical purity of 92.05%. Docking accuracy and scoring reliability for the new nitro-zoledronate with human GGPPS using MOE software has been presented.Results and Conclusion: The nitro-zoledronate successfully coupled with technetium-99m at high yield to investigate its in-vivo biodistribution which indicated highly selective uptake in the skeletal system and rapid clearance from soft tissues. The in-vitro cytotoxicity of the nitro-zoledronate was evaluated and potently inhibited the osteosarcoma cell line (MG-63) after 72 hours with an IC50 value of 10 μM. To summarize, our data point to a promising candidate to improve osteosarcoma therapy.

Anti-VEGF Drugs in the Treatment of Multiple Myeloma Patients

The interaction between the bone marrow microenvironment and plasma cells plays an essential role in multiple myeloma progression and drug resistance. The vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) pathway in vascular endothelial cells activates and promotes angiogenesis. Moreover, VEGF activates and promotes vasculogenesis and vasculogenic mimicry when it interacts with VEGF receptors expressed in precursor cells and inflammatory cells, respectively. In myeloma bone marrow, VEGF and VEGF receptor expression are upregulated and hyperactive in the stromal and tumor cells. It has been demonstrated that several antiangiogenic agents can effectively target VEGF-related pathways in the preclinical phase. However, they are not successful in treating multiple myeloma, probably due to the vicarious action of other cytokines and signaling pathways. Thus, the simultaneous blocking of multiple cytokine pathways, including the VEGF/VEGFR pathway, may represent a valid strategy to treat multiple myeloma. This review aims to summarize recent advances in understanding the role of the VEGF/VEGFR pathway in multiple myeloma, and mainly focuses on the transcription pathway and on strategies that target this pathway.

A Comprehensive Biological and Clinical Perspective Can Drive a Patient-Tailored Approach to Multiple Myeloma: Bridging the Gaps between the Plasma Cell and the Neoplastic Niche

There is a broad spectrum of diseases labeled as multiple myeloma (MM). This is due not only to the composite prognostic risk factors leading to different clinical outcomes and responses to treatments but also to the composite tumor microenvironment that is involved in a vicious cycle with the MM plasma cells. New therapeutic strategies have improved MM patients' chances of survival. Nevertheless, certain patients' subgroups have a particularly unfavorable prognosis. Biological stratification can be subdivided into patient, disease, or therapy-related factors. Alternatively, the biological signature of aggressive disease and dismal therapeutic response can promote a dynamic, comprehensive strategic approach, better tailoring the clinical management of high-risk profiles and refractoriness to therapy and taking into account the role played by the MM milieu. By means of an extensive literature search, we have reviewed the state-of-the-art pathophysiological insights obtained from translational investigations of the MM-bone marrow microenvironment. A good knowledge of the MM niche pathophysiological dissection is crucial to tailor personalized approaches in a bench-bedside fashion. The discussion in this review pinpoints two main aspects that appear fundamental in order to gain novel and definitive results from the biology of MM. A systematic knowledge of the plasma cell disorder, along with greater efforts to face the unmet needs present in MM evolution, promises to open a new therapeutic window looking out onto the plethora of scientific evidence about the myeloma and the bystander cells.

Zoledronate Inhibits Osteoclast Differentiation via Suppressing Vascular Endothelial Growth Factor Receptor 2 Expression

Bisphosphonate-related osteonecrosis of the jaw (ONJ) is a major oral complication; however, its pathogenesis remains unclear. Impairment of osteoclast differentiation by bisphosphonates may be associated with the pathogenesis of ONJ. In our previous study, we reported that the expression of the gene encoding nuclear factor of activated T cells c1 (NFATc1), a known osteoclast differentiation marker, was significantly silenced by zoledronate, a bisphosphonate, in mouse osteoclast precursor cells (mOCPCs) using cDNA microarray. In the present study, the expression value of the NFATc1 gene was regarded as a cut-off and genes whose expression value was significantly decreased compared with that of the NFATc1 gene were extracted in mOCPCs. For validation, CD11b-positive (CD11b+) cells were used, which were purified from human peripheral blood mononuclear cells as human OCPCs. A total of 19 genes were identified; sequential expression analysis revealed that the gene encoding vascular endothelial growth factor receptor 2 (VEGFR2) was frequently silenced by zoledronate in CD11b+ cells. Furthermore, the number of tartrate-resistant acid phosphatase-positive multinucleated cells was decreased by VEGFR2 suppression using a VEGFR2 neutralizing antibody. Zoledronate inhibits human osteoclast differentiation via suppressing VEGFR2 expression. These results suggest that low expression of VEGFR2 in OCPCs may be involved in the pathogenesis of zoledronate-induced ONJ. The understanding of the role of VEGFR2 on bone remodeling is important to elucidate the pathogenesis of bisphosphonate-related ONJ.

Bone Marrow Stromal Cells-Induced Drug Resistance in Multiple Myeloma

Multiple myeloma is a B-cell lineage cancer in which neoplastic plasma cells expand in the bone marrow and pathophysiological interactions with components of microenvironment influence many biological aspects of the malignant phenotype, including apoptosis, survival, proliferation, and invasion. Despite the therapeutic progress achieved in the last two decades with the introduction of a more effective and safe new class of drugs (i.e., immunomodulators, proteasome inhibitors, monoclonal antibodies), there is improvement in patient survival, and multiple myeloma (MM) remains a non-curable disease. The bone marrow microenvironment is a complex structure composed of cells, extracellular matrix (ECM) proteins, and cytokines, in which tumor plasma cells home and expand. The role of the bone marrow (BM) microenvironment is fundamental during MM disease progression because modification induced by tumor plasma cells is crucial for composing a "permissive" environment that supports MM plasma cells proliferation, migration, survival, and drug resistance. The "activated phenotype" of the microenvironment of multiple myeloma is functional to plasma cell proliferation and spreading and to plasma cell drug resistance. Plasma cell drug resistance induced by bone marrow stromal cells is mediated by stress-managing pathways, autophagy, transcriptional rewiring, and non-coding RNAs dysregulation. These processes represent novel targets for the ever-increasing anti-MM therapeutic armamentarium.

The chick embryo chorioallantoic membrane as an in vivo experimental model to study multiple myeloma

The chick embryo chorioallantoic membrane (CAM) has long been used as an in vivo assay for the study of tumor angiogenesis because when tumor grafts are placed at day 6-10 days of incubation the chick's immunocompetent system is not fully developed and the conditions for rejection have not been yet established. All studies for mammalian neoplasms, including multiple myeloma, have utilized tumor cell lines, tumor bioptic specimens, cell suspensions derived from tumors, mouse tumor xenografts bioptic specimens. CAM can also be used to study the effects of anti-angiogenic molecules on tumor cell suspensions of tumor bioptic specimens. This review article summarizes and discussed our experience concerning the use of the CAM to study multiple myeloma.

Bisphosphonates and Cancer: A Relationship Beyond the Antiresorptive Effects

Bisphosphonates (BPs) are stable analogues of the Inorganic Pyrophosphate (PPi), an endogenous regulator of bone mineralization, which can resist the hydrolysis in the gastrointestinal tract. Their conformation allows targeting the bone as a result of their three-dimensional structure, which makes them primary agents against osteoclast-mediated bone loss. They are used in many bone pathological conditions, like bone metastasis, because of its ability to modulate bone metabolism into a less favorable place to cancer cell growth, through the inhibition of osteoclastogenesis and bone resorption. This review is focused on the mechanisms of action through which BPs affect the cellular activity and survival, mainly on their antitumoral effects. In conclusion, BPs are considered the primary therapy for skeletal disorders due to its high affinity for bone, but now they are also considered as potential antitumor agents due to its ability to induce tumor cell apoptosis, inhibition of cell adhesion, invasion and proliferation, modulation of the immune system to target and eliminate cancer cells as well as affect the angiogenic mechanisms. Like any other drug, they also have some adverse effects, but the most common, the acute phase reaction, can be minimized with the intake of calcium and vitamin D.

New Insights in Anti-Angiogenesis in Multiple Myeloma

Angiogenesis is a constant hallmark of multiple myeloma (MM) progression and involves direct production of angiogenic cytokines by plasma cells and their induction within the bone marrow microenvironment. This article summarizes the more recent literature data concerning the employment of anti-angiogenic therapeutic agents actually used in preclinical models and clinical settings for the treatment of multiple myeloma.

Bone Marrow Stroma and Vascular Contributions to Myeloma Bone Homing

PURPOSE OF THE REVIEW

Herein we dissect mechanisms behind the dissemination of cancer cells from primary tumor site to the bone marrow, which are necessary for metastasis development, with a specific focus on multiple myeloma.

RECENT FINDINGS

The ability of tumor cells to invade vessels and reach the systemic circulation is a fundamental process for metastasis development; however, the interaction between clonal cells and the surrounding microenvironment is equally important for supporting colonization, survival, and growth in the secondary sites of dissemination. The intrinsic propensity of tumor cells to recognize a favorable milieu where to establish secondary growth is the basis of the "seed and soil" theory. This theory assumes that certain tumor cells (the "seeds") have a specific affinity for the milieu of certain organs (the "soil"). Recent literature has highlighted the important contributions of the vascular niche to the hospitable "soil" within the bone marrow. In this review, we discuss the crucial role of stromal cells and endothelial cells in supporting primary growth, homing, and metastasis to the bone marrow, in the context of multiple myeloma, a plasma cell malignancy with the unique propensity to primarily grow and metastasize to the bone marrow.

Role of Endothelial Cells and Fibroblasts in Multiple Myeloma Angiogenic Switch

Multiple myeloma (MM) mainly progresses in bone marrow (BM). Therefore, signals from the BM microenvironment are thought to play a critical role in maintaining plasma cell growth, migration, and survival. Reciprocal positive and negative interactions between plasma cells and microenvironmental cells, including endothelial cells (ECs) and fibroblasts may occur. The BM neovascularization is a constant hallmark of MM, and goes hand in hand with progression to leukemic phase. Microenvironmental factors induce MMECs and fibroblasts to become functionally different from monoclonal gammopathy of undetermined significance (MGUS) ECs (MGECs), i.e., to acquire an overangiogenic phenotype, and be similar to transformed cells. These alterations play an important role in MM progression and may represent new molecular markers for prognostic stratification of patients and prediction of response to antiangiogenic drugs, as well as new potential therapeutic targets.

Bisphosphonate-Functionalized Imaging Agents, Anti-Tumor Agents and Nanocarriers for Treatment of Bone Cancer

Bone metastases result from the invasion of primary tumors to bone. Current treatment modalities include local treatments such as surgery and radiotherapy, while systemic treatments include chemotherapy and (palliative) treatment of skeletal metastases. Nevertheless, once bone metastases have been established they remain incurable leading to morbidity and mortality. Bisphosphonates are a well-established class of drugs, which are increasingly applied in the treatment of bone cancers owing to their effective inhibition of tumor cells and suppression of bone metastases. The increased understanding of the mechanism of action of bisphosphonates on bone and tumor cells has prompted the development of novel bisphosphonate-functionalized imaging and therapeutic agents. This review provides an update on the preclinical efficacy of bisphosphonate-functionalized fluorophore, anti-tumor agents and nanocarriers for the treatment of bone metastases. After an overview of the general characteristics of bisphosphonates and their mechanisms of action, an outline is provided on the various conjugation strategies that have become available to functionalize imaging agents, anti-tumor agents and nanocarriers with bisphosphonates. Finally, the efficacy of these bisphosphonate-modified agents and carriers in preclinical studies is evaluated by reviewing their potential to target tumors and inhibit tumor growth in clinically relevant animal models for the treatment of bone cancer.

Bisphosphonates for cancer treatment: Mechanisms of action and lessons from clinical trials

A growing body of evidence points toward an important anti-cancer effect of bisphosphonates, a group of inexpensive, safe, potent, and long-term stable pharmacologicals that are widely used as osteoporosis drugs. To date, they are already used in the prevention of complications of bone metastases. Because the bisphosphonates can also reduce mortality in among other multiple myeloma, breast, and prostate cancer patients, they are now thoroughly studied in oncology. In particular, the more potent nitrogen-containing bisphosphonates have the potential to improve prognosis. The first part of this review will elaborate on the direct and indirect anti-tumoral effects of bisphosphonates, including induction of tumor cell apoptosis, inhibition of tumor cell adhesion and invasion, anti-angiogenesis, synergism with anti-neoplastic drugs, and enhancement of immune surveillance (e.g., through activation of γδ T cells and targeting macrophages). In the second part, we shed light on the current clinical position of bisphosphonates in the treatment of hematological and solid malignancies, as well as on ongoing and completed clinical trials investigating the therapeutic effect of bisphosphonates in cancer. Based on these recent data, the role of bisphosphonates is expected to further expand in the near future outside the field of osteoporosis and to open up new avenues in the treatment of malignancies.

Microenvironment and multiple myeloma spread

In patients with multiple myeloma (MM), the bone marrow (BM) contains hematopoietic stem cells (HSCs) and non-hematopoietic cells. HSCs are able to give rise to all types of mature blood cells, while the non hematopoietic component includes mesenchymal stem cells (MSCs), fibroblasts, osteoblasts, osteoclasts, chondroclasts, endothelial cells, endothelial progenitor cells (EPCs), B and T lymphocytes, NK cells, erythrocytes, megakaryocytes, platelets, macrophages and mast cells. All of these cells form specialized "niches" in the BM microenvironment which are close to the vasculature ("vascular niche") or to the endosteum ("osteoblast niche"). The "vascular niche" is rich in blood vessels where endothelial cells and mural cells (pericytes and smooth muscle cells) create a microenvironment that affects the behavior of several stem and progenitor cells. The vessel wall serves as an independent niche for the recruitment of endothelial progenitor cells, MSCs and HSCs. The activation by angiogenic factors and inflammatory cytokines switch the "vascular niche" to promote MM tumor growth and spread. This review will focus on the mechanisms involved in the generation of signals released by endothelial cells in the "vascular niche" that promote tumor growth and spread in MM.

Multiple myeloma as a model for the role of bone marrow niches in the control of angiogenesis

Bone marrow (BM) contains hematopoietic stem cells (HSCs) and nonhematopoietic cells. HSCs give rise to all types of mature blood cells, while the nonhematopoietic component includes osteoblasts/osteoclasts, endothelial cells (ECs), endothelial progenitor cells (EPCs), and mesenchymal stem cells (MSCs). These cells form specialized "niches" which are close to the vasculature ("vascular niche") or to the endosteum ("osteoblast niche"). The "vascular niche", rich in blood vessels where ECs and mural cells (pericytes and smooth muscle cells), create a microenvironment affecting the behavior of several stem and progenitor cells. The vessel wall acts as an independent niche for the recruitment of EPCs and MSCs. This chapter will focus on the description of the role of BM niches in the control of angiogenesis occurring during multiple myeloma progression.

The chick embryo chorioallantoic membrane as a model for tumor biology

Among the in vivo models, the chick embryo chorioallantoic membrane (CAM) has been used to implant several tumor types as well as malignant cell lines to study their growth rate, angiogenic potential and metastatic capability. This review article is focused on the major compelling literature data on the use of the CAM to investigate tumor growth and the metastatic process.

Pleiotropic effects of bisphosphonates on osteosarcoma

Osteosarcoma is the most common primary malignant tumor of bone and accounts for half of all primary skeletal malignancies in children and teenagers. The prognosis for patients who fail or progress on first-line chemotherapy protocols is poor, therefore, additional adjuvant therapeutic strategies are needed. A recent feasibility study has demonstrated that the nitrogen-containing bisphosphonate zoledronic acid (ZOL) can be combined safely with conventional chemotherapy. However, the pharmacodynamics of bisphosphonate therapy is not well characterized. Osteosarcoma is a highly angiogenic tumor. Recent reports of the anti-angiogenic effects of bisphosphonates prompted us to determine whether nitrogen-containing bisphosphonate (ZOL and alendronate) treatment attenuates osteosarcoma growth by inhibition of osteoclast activity, tumor-mediated angiogenesis, or direct inhibitory effects on osteosarcoma. Here, we demonstrate that bisphosphonates directly inhibit VEGFR2 expression in endothelial cells, as well as endothelial cell proliferation and migration. Additionally, bisphosphonates also decrease VEGF-A expression in osteosarcoma (K7M3) cells, resulting in reduced stimulation of endothelial cell migration in co-culture assays. ZOL also decreases VEGFR1 expression in aggressive osteosarcoma cell lines (K7M3, 143B) and induces apoptosis of these cells, but has negligible effects on less aggressive osteosarcoma cell lines (K12 and TE85). In vivo ZOL treatment results in significant reduction in osteosarcoma-initiated angiogenesis and tumor growth in a murine model of osteosarcoma. In conclusion, bisphosphonates have diverse growth inhibitory effects on osteosarcoma through: (1) activation of apoptosis and inhibition of cell proliferation, (2) inhibition of VEGF-A and VEGFR1 expression by tumor cells, (3) inhibition of tumor-induced angiogenesis, and (4) direct inhibitory actions on endothelial cells.

Bisphosphonates induce the osteogenic gene expression in co-cultured human endothelial and mesenchymal stem cells

Bisphosphonates (BPs) are known to affect bone homeostasis and also to have anti-angiogenic properties. Because of the intimate relationship between angiogenesis and osteogenesis, this study analysed the effects of Alendronate (AL) and Zoledronate (ZL) in the expression of endothelial and osteogenic genes on interacting endothelial and mesenchymal stem cells, an issue that was not previously addressed. Alendronate and ZL, 10(-12) -10(-6) M, were evaluated in a direct co-culture system of human dermal microvascular endothelial cells (HDMEC) and human bone marrow mesenchymal stem cells (HMSC), over a period of 14 days. Experiments with the respective monocultures were run in parallel. Alendronate and ZL caused an initial dose-dependent stimulation in the cell proliferation in the monocultures and co-cultures, and did not interfere with their cellular organization. In HDMEC monocultures, the expression of the endothelial genes CD31, VE-cadherin and VEGFR2 was down-regulated by AL and ZL. In HMSC monocultures, the BPs inhibited VEGF expression, but up-regulated the expression of the osteogenic genes alkaline phosphatase (ALP), bone morphogenic protein-2 (BMP-2) and osteocalcin (OC) and, to a greater extent, osteoprotegerin (OPG), a negative regulator of the osteoclastic differentiation, and increased ALP activity. In co-cultured HDMEC/HMSC, AL and ZL decreased the expression of endothelial genes but elicited an earlier and sustained overexpression of ALP, BMP-2, OC and OPG, compared with the monocultured cells; they also induced ALP activity. This study showed for the first time that AL and ZL greatly induced the osteogenic gene expression on interacting endothelial and mesenchymal stem cells.

Zoledronic acid inhibits human osteoblast activities

BACKGROUND

Bisphosphonates are potent inhibitors of bone resorption. These kinds of drugs, which are used for the treatment of osteolytic diseases, have been associated with the occurrence of oral osteonecrosis, especially in patients over 60 years old. Current studies have demonstrated that the cytotoxic effects of bisphosphonates on osteoblasts play an important role in oral osteonecrosis development.

OBJECTIVE

The aim of this study was to evaluate the effect of long-term application of a highly potent bisphosphonate - zoledronic acid (ZA) - on human osteoblasts in vitro.

METHODS

Human osteoblasts (MG63 cell line) were seeded for 72 h in wells of 24-well plates. The Dulbecco's modified Eagle's medium (DMEM) was then replaced by culture medium without fetal bovine serum (FBS), and the cells were incubated for an additional 24 h, after which ZA was added to the DMEM without FBS and incubated in contact with osteoblasts for 7, 14 or 21 days. Cell viability (CV), total protein production (TPP), alkaline phosphatase (ALP) activity, mineral nodule formation (MNF), and gene expression of ALP and osteocalcin (OCN), as well as cell morphology by scanning electronic microscopy, were evaluated. Data were statistically analyzed by Kruskal-Wallis and Mann-Whitney tests, with a significance level of 5%.

RESULTS

The cytotoxic effects of ZA on osteoblasts were characterized by reduction of CV, TPP, ALP and MNF production. In addition, ZA MNF caused a decrease in gene expression of ALP and OCN, as well as intense cell morphology alterations. All these negative effects of ZA were concentration and period dependent.

CONCLUSION

Both concentrations of ZA (1 and 5 μM) caused cytotoxic effects to osteoblasts which reduced the production and expression of proteins that play an important role in bone matrix synthesis and mineralization.

Pathologic fractures in bisphosphonate-related osteonecrosis of the jaw-review of the literature and review of our own cases

Background Bisphosphonates are powerful drugs used for the management of osteoporosis and metastatic bone disease to avoid skeletal-related complications. Side effects are rare but potentially serious such as the bisphosphonate-related osteonecrosis of the jaws (BRONJ). BRONJ impairs the quality of life and can even lead to pathologic fractures of the mandible. Management of BRONJ is difficult per se. If complicated with pathologic mandibular fractures in advanced stages, the treatment options are controversially discussed. This review delineates the epidemiology and pathogenesis of BRONJ to put the various modalities for the treatment of pathologic mandible fractures into perspective. Methods Various case reports and case series in the literature were reviewed. Cases were reviewed of patients suffering from pathologic fracture due to bisphosphonate-related osteonecrosis of the jaw treated in the Department of Oral and Maxillofacial Surgery (Ludwig-Maximilians-University of Munich) from 2003 to 2010. Of 140 patients suffering from BRONJ, four were identified with pathologic fracture of the mandible. Results Management of pathologic mandibular fractures in patients suffering from BRONJ is an unsolved issue. At present there is a paucity of information to establish reliable therapy guidelines. The published strategies range from conservative treatment to major bone resections with or without internal or external fixation and with or without autogenous reconstruction. There is no evidence for the superiority of a single therapeutic mode, however. Conclusion Further understanding of BRONJ is mandatory to establish a sound rationale for the treatment of associated mandibular fractures.

Cost-effectiveness of zoledronic acid compared with clodronate in multiple myeloma

BACKGROUND

In the U.K. Medical Research Council Myeloma IX trial (mmix), zoledronic acid 4 mg once every 3-4 weeks, compared with clodronate 1600 mg daily, reduced the incidence of skeletal related events (sres), increased progression-free survival (pfs), and prolonged overall survival (os) in 1970 patients with newly-diagnosed multiple myeloma. The incidence of confirmed osteonecrosis of the jaw was higher with zoledronic acid than with clodronate. The objective of the present study was to evaluate, based on the findings in mmix, the cost-effectiveness of zoledronic acid compared with clodronate in patients with newly-diagnosed multiple myeloma.

METHODS

An economic model was used to project pfs, os, the incidence of sres and adverse events, and expected lifetime health care costs for patients with newly diagnosed multiple myeloma who are alternatively assumed to receive zoledronic acid or clodronate. The incremental cost-effectiveness ratio (icer) of zoledronic acid compared with clodronate was calculated as the ratio of the difference in cost to the difference in quality-adjusted life years (qalys). Model inputs were based on results of mmix and published sources. Results were generated under different assumptions regarding the beneficial effects of zoledronic acid on os beyond 5 years after treatment initiation.

RESULTS

Assuming lifetime treatment effects of zoledronic acid, treatment with zoledronic acid (compared with clodronate) increased qalys by 0.27 at an additional cost of CA$13,407, yielding an icer of CA$49,829 per qaly gained. If the threshold icer is CA$100,000 per qaly, the estimated probability that zoledronic acid is cost-effective is 80%. Assuming that the benefits of zoledronic acid on pfs and os diminish over 5 years beginning at the end of year 5, the icer is CAN$63,027 per qaly gained. If the benefits of zoledronic acid on pfs and os are assumed to persist for 5 years only, the icer is CAN$76,948 per qaly gained.

CONCLUSIONS

Compared with clodronate, zoledronic acid represents a cost-effective treatment alternative in patients with multiple myeloma.

Zoledronic acid enhances the effect of radiotherapy for bone metastases from renal cell carcinomas: more than a 24-month median follow-up

BACKGROUND

Renal cell carcinoma (RCC) is thought to respond unreliably to radiotherapy (RT). Zoledronic acid significantly reduces the risk of skeletal complications. This study investigated whether RT with zoledronic acid prolonged the time to bone-lesion progression in comparison with RT alone.

METHOD

Twenty-seven patients (34 lesions) with bone metastases secondary to RCC undergoing treatment with RT with or without zoledronic acid were retrospectively evaluated at two institutions between 1999 and 2009. Twelve patients were treated with RT alone from 1999 to 2008 (RT group). Fifteen patients were treated with RT and zoledronic acid from 2006 to 2009 (RT + Z group). The time to skeletal-related events and pain progression were assessed from patients' medical records.

RESULTS

The median (range) follow-up was 26 (3-75) and 24 (3-55) months in the RT and RT + Z groups, respectively. Three patients (three lesions) in the RT + Z group had skeletal-related events (SREs). In contrast, six patients (eight lesions) in the RT group had SREs. SREs comprised pathological fractures in five, additional surgeries in three, spinal cord or cauda equine compression in two, and repeat RT in one. There was a significant difference in SRE-free survival time and duration of site-specific pain response between groups.

CONCLUSIONS

RT combined with zoledronic acid significantly prolonged SRE-free survival and duration of pain response compared with RT alone in the treatment of osseous metastases from RCC.

Long-term success of surgery in bisphosphonate-related osteonecrosis of the jaws (BRONJs)

OBJECTIVES

Bisphosphonates are associated with osteonecrosis of the jaw. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) may be treated conservatively or by surgery.

PATIENTS AND METHODS

108 patients underwent surgery and 88 patients were followed for a mean period of 337 days. Age, gender, dental procedures, underlying disease, and the role of bisphosphonate treatment in the success of surgery were evaluated retrospectively.

RESULTS

Surgical treatment improved the stage distribution from 19% stage I, 56% stage II and 25% stage III to 59% intact mucosa, 19% stage I and 13% stage II and 8% stage III. The improvement in the stage of disease achieved by surgery was statistically significant. Further relevant parameters that favor a positive outcome of surgery were the event triggering the outbreak of BRONJ (p=0.05) and the underlying disease (p=0.05). BRONJ in the maxilla necessitated repeat surgery significantly earlier than did BRONJ in the mandible (p=0.03).

CONCLUSION

Effective surgery might improve the outcome of BRONJ, although prevention still is the most important aspect of this condition.

Antiangiogenic effects of zoledronate on cancer neovasculature

Angiogenesis, one of the hallmarks of cancer, supplies nutrients to cancerous tissues to facilitate rapid growth. Targeting cancer-associated angiogenesis is an important goal in cancer therapy and there are currently many drugs that affect tumor-associated vasculature. In this article, we will focus on the antiangiogenic effects of zoledronate (ZA), a bisphosphonate drug routinely used in the treatment of cancer-associated bone disease. This article covers the known effects of ZA throughout the clinical process. It also covers the animal models of cancer that have been treated with ZA and evaluated for angiogenes is, concluding with the current clinical data pertaining to angiogenic factors after ZA treatment.

Bisphosphonate and Osteonecrosis of the Jaw: The Oral Surgeon's Perspective

Bisphosphonates (BPs) are an important class of drugs, useful in the treatment of some metabolic and oncologic skeletal diseases. BPs have shown a sure effectiveness in the treatment and in the palliative care of such pathologies; on the other hand, an avascular osteonecrosis of the jaws (B-ONJ = Bisphosphonate OsteoNecrosis of the Jaw) has recently been reported as an adverse effect not only of BP intravenous infusions, but also of their prolonged oral administration. B-ONJ normally follows a dental extraction or other surgical procedure in the oral cavity, but it also can develop spontaneously. In the latter case, some systemic risk factors, such as comorbidities and co-therapies or jaw anatomical conditions, can play a leading role in the onset of this pathologic condition. B-ONJ is an uncommon but potentially serious complication of BP therapy that can gravely affect the patient's quality of life, producing significant morbidity. To date, no therapies are completely effective and predictable in the treatment of B-ONJ, therefore prevention should be strongly promoted by sharing knowledge in the involved medical community.

Cost-effectiveness of zoledronic acid vs clodronic acid for newly-diagnosed multiple myeloma from the United Kingdom healthcare system perspective

OBJECTIVE

In the Medical Research Council Myeloma IX Study (MMIX), zoledronic acid (ZOL) 4 mg 3-4/week reduced the incidence of skeletal-related events (SREs), increased progression free survival (PFS), and prolonged overall survival (OS), compared with clodronic acid (CLO) 1600 mg daily, in 1970 patients with newly-diagnosed multiple myeloma (MM).

METHODS

An economic model was used to project PFS, OS, the incidence of SREs and adverse events and expected lifetime healthcare costs for patients with newly-diagnosed MM who are alternatively assumed to receive ZOL or CLO. The incremental cost-effectiveness ratio [ICER] of ZOL vs CLO was calculated as the ratio of the difference in cost to the difference in quality-adjusted life years (QALYs). Model inputs were based on results of MMIX and published sources.

RESULTS

Compared with CLO, treatment with ZOL increases QALYs by 0.30 at an additional cost of £1653, yielding an ICER of £5443 per QALY gained. If the threshold ICER is £20,000 per QALY, the estimated probability that ZOL is cost-effective is 90%.

LIMITATIONS

The main limitation of this study is the lack of data on the effects of zoledronic acid on survival beyond the end of follow-up in the MMIX trial. However, cost-effectiveness was favourable even under the highly conservative scenario in which the timeframe of the model was limited to 5 years.

CONCLUSIONS

Compared with clodronic acid, zoledronic acid represents a cost-effective treatment alternative in patients with multiple myeloma.

Vγ9Vδ2 T cell-based immunotherapy in hematological malignancies: from bench to bedside

Many hematological malignancies consist of tumor cells that are spontaneously recognized and killed by Vγ9Vδ2 T cells. These tumor cells generate high amounts of intracellular phosphorylated metabolites mimicking the natural ligands and display a wide range of stress-induced self-ligands that are recognized by Vγ9Vδ2 T cells via TCR-dependent and TCR-independent mechanisms. The intrinsic features of Vγ9Vδ2 T cells and that of tumor cells of hematological origin constitute an ideal combination from which to develop Vγ9Vδ2 T cell-based immune interventions. In this review, we will discuss the rationale, preclinical and clinical data in favor of this therapeutic strategy and the future perspectives of its development.

The backbone of progress--preclinical studies and innovations with zoledronic acid

Bisphosphonates (BPs) are antiresorptive agents that block pathologic bone resorption by inhibiting osteoclast function and later inducing osteoclast apoptosis. These agents localize to bone and break the vicious cycle of bone resorption that results from cross-stimulation between cancer cells and the bone remodeling cells, thereby reducing cancer-induced osteolysis and the tumor burden in bone. Thus nitrogen-containing BPs (N-BPs) have well established clinical benefits in the treatment of bone metastases from solid tumors and bone lesions from multiple myeloma. Preclinical data indicate that N-BPs, especially zoledronic acid (ZOL), can exert antimyeloma activity both in vitro and in vivo. Studies show that N-BPs can inhibit multiple intracellular processes essential for cancer cell proliferation and invasion and induce apoptosis. Furthermore, clinically relevant doses of N-BPs inhibit tumor-associated angiogenesis and can modulate macrophage phenotype in vivo, which is likely to contribute to anticancer effects.

The role of bisphosphonates in multiple myeloma: mechanisms, side effects, and the future

Zoledronic acid and pamidronate are two potent anticatabolic nitrogen-containing bisphosphonates (BPs) used extensively in diseases with high bone turnover such as multiple myeloma (MM). In this review we focus on their biology and their current and future use in MM, and highlight some of the most common and emerging side effects. Although the primary target cells for BPs are osteoclasts, new insights suggest other cell types of the bone microenvironment as possible targets, including osteoblasts, endothelial cells, immune cells, and cancer cells. Here, we focus on the current guidelines for the use of BPs in MM and address side effects such as renal toxicity, osteonecrosis of the jaw, and low-energy fractures. Finally, we approach the future of BP use in MM in the context of other bone-targeted agents, evaluating ongoing clinical trials addressing alternate dosing and schedules of BP administration in MM patients.

The Chick Embryo Chorioallantoic Membrane as an In Vivo Assay to Study Antiangiogenesis

Antiangiogenesis, e.g., inhibition of blood vessel growth, is being investigated as a way to prevent the growth of tumors and other angiogenesis-dependent diseases. Pharmacological inhibition interferes with the angiogenic cascade or the immature neovasculature with synthetic or semi-synthetic substances, endogenous inhibitors or biological antagonists.The chick embryo chorioallantoic membrane (CAM) is an extraembryonic membrane, which serves as a gas exchange surface and its function is supported by a dense capillary network. Because its extensive vascularization and easy accessibility, CAM has been used to study morphofunctional aspects of the angiogenesis process in vivo and to study the efficacy and mechanism of action of pro- and anti-angiogenic molecules. The fields of application of CAM in the study of antiangiogenesis, including our personal experience, are illustrated in this review article.

New and emerging treatments for osteoporosis

A variety of new treatments for osteoporosis have become available within the last several years, and a number of emerging treatments remain in late clinical stage development. New and emerging treatments include more potent members, or more convenient formulations, of existing classes of therapy, but a number of the emerging treatments are first-generation compounds addressing specific therapeutic targets based on recent advances in understanding of basic bone biology. These new and emerging treatments include agents with anticatabolic effects, compounds with anabolic effects, and one agent possibly containing both anticatabolic and anabolic effects. The increasing variety of new and emerging treatments increases the possibility that effective therapy will be targeted to the specific needs of the individual patient.

Modulation of murine bone marrow-derived CFU-F and CFU-OB by in vivo bisphosphonate and fluoride treatments

OBJECTIVES

Bisphosphonates (BPN) have actions on a variety of cell types including: osteoclasts, osteoblasts, osteocytes, and endothelial cells. The objectives of this report are to review the current state of understanding of the effects of BPNs on orthodontic tooth movement and to provide evidence on BPN's in vivo effects on bone marrow-derived osteoprogenitor cells.

MATERIAL AND METHODS

Mice from the C3H/HeJ (C3H), C57BL/6J (B6), FVB/NJ (FVB), and BALB/cByJ (BALB) strains were treated for 3 weeks with 0, 3, 30, or 150 mcg/kg/week alendronate (ALN) administered subcutaneous alone or in combination with 50 ppm fluoride (F). Bone marrow cells were harvested and subjected to in vitro colony-forming unit fibroblast (CFU-F) and colony-forming unit osteoblasts (CFU-OB) assays.

RESULTS

Baseline differences in CFU-F, CFU-OB/ALP+, and CFU-OB/total were observed among the four strains. Strain-specific responses to ALN and F treatments were observed for CFU-F, CFU-OB/ALP+, and CFU-OB/total. F treatment alone resulted in decreases in CFU-F (p = 0.013), CFU-OB/ALP+ (p = 0.005), and CFU-OB/total (p = 0.003) in the C3H strain. CFU-F (p = 0.036) were decreased by F in the B6 strain. No significant (NS) effects of F were observed for FVB and BALB. ALN treatment resulted in a significant decrease in CFU-F (p = 0.0014) and CFU-OB/total (p = 0.028) in C3H only. ALN treatment had NS effect on CFU-OB/ALP+ in all four strains.

CONCLUSION

Genetic factors appear to play a role in ALN's effects on CFU-F and CFU-OB/total but not on CFU-OB/ALP+.

Bisphosphonate-associated osteonecrosis of the jaw: what do we currently know? A survey of knowledge given in the recent literature

Increasing application of bisphosphonates for therapy of osteopathies has led to reports of the severe associated adverse effects of osteonecrosis of the jaw (ONJ). We reviewed recent literature to assess several aspects of bisphosphonate-associated ONJ, and to provide healthcare professionals with an overview of treatment and preventive options. Literature databases were searched using keywords. Information of 54 articles were discussed and completed by additional literature. High-risk factors were application of nitrogen-containing bisphosphonates, teeth extractions, and ill-fitting dentures. Treatment included non-surgical options and radical surgery. Success and failure were described for all treatment options; further studies investigating long-term recovery and recurrence are warranted. Paying attention to effective prevention of ONJ before, during, and after treatment is essential.

Higher incidence of Osteonecrosis of the Jaw (ONJ) in patients with metastatic castration resistant prostate cancer treated with anti-angiogenic agents

ONJ is an important toxicity in cancer patients receiving bisphosphonate therapy. Here we report a higher than usual incidence of ONJ, 11 of 60 (18.3%, 95% Confidence Interval, CI: 9%-28%) patients enrolled in a phase II clinical trial combining bevacizumab, docetaxel, thalidomide, and prednisone (ATTP) in chemotherapy-naive men with metastatic castration resistant prostate cancer (mCRPC). The use of bisphosphonates was allowed at study entry. Our study suggests that anti-angiogenic and chemotherapy agents can predispose to the development of ONJ in men with mCRPC on zoledronic acid. Imaging modalities, such as bone scans, may be useful in following the clinical course of patients who develop ONJ.