Whole body MR in patients with multiple myeloma

BackgroundMultiple myeloma is a cancer of plasma cells which leads to bone marrow infiltration.AimWhole-body MR is the most sensitive imaging method available to detect multiple myeloma lesions.Material and MethodsMR scans were performed in 100 patients with multiple myeloma who were receiving treatment in the Haematology Clinic in Poznań in the years 2005–2006. Whole-body MR scans were performed with general coil 1.0 T in STIR sequences and T1 sequences, in coronal and sagittal planes with scanning area covering the head, neck, trunk and the limbs (FOV for specific regions was 36–48 cm). The bone lesions were classified as focal (monofocal/multifocal lesions), in-filtrative, mixed and “salt and pepper” type. Depending on the size of the lesions the patients were included in one of three groups according to Salmon-Durie Plus classification.ResultsFour main types of multiple myeloma were distinguished based on MR scans: focal (48 patients; monofocal in 10 patients), infiltrative (17 patients), mixed type (19 patients) and “salt and pepper” type (4 patients). The remaining 12 patients had no multiple myeloma lesions in the bone marrow. Additionally, in 18% of patients a soft tissue mass could be observed. According to Salmon-Durie Plus categorisation 27 subjects were classified as having stage I, 16 patients stage and 57 patients stage III disease. In 12% of patients MR data changed the disease staging.ConclusionsWB MR is a sensitive and effective diagnostic method with an important impact on staging and further treatment of multiple myeloma.     

Paleopathological Description and Diagnosis of Metastatic Carcinoma in an Early Bronze Age (4588+34 Cal. BP) Forager from the Cis-Baikal Region of Eastern Siberia

Extensive osteolytic and osteoblastic lesions were observed on the skeletal remains of an adult male excavated from an Early Bronze Age cemetery dated to 4556+32 years BP, located in the Cis-Baikal region of Siberia (Russian Federation). Lytic lesions ranged in size from several mm to over 60 mm in diameter and had irregular, moth-eaten borders. Many of these lesions destroyed trabecular bone, though a hollowed shell of cortical bone often remained observable. Radiographic analysis revealed numerous lytic lesions within trabecular bone that had not yet affected the cortex. Blastic lesions were identified as spiculated lines, bands, or nodules of mostly immature (woven) bone formed at irregular intervals. Anatomical elements with the greatest involvement included those of the axial skeleton (skull, vertebrae, sacrum, ribs, and sternum) as well as proximal appendicular elements (ossa coxae, proximal femora, clavicles, scapulae, and proximal humeri). Osteocoalescence of destructive foci was observed on the ilium and frontal bone, with the largest lesion found on the right ilium. Differential diagnoses include metastatic carcinoma, mycotic infections, tuberculosis, Langerhan''s cell histiocytosis, and multiple myeloma. Based on lesion appearance and distribution, age and sex of the individual, as well as pathogen endemism, the most likely diagnostic option for this set of lesions is metastatic carcinoma. The age and sex of this individual and appearance of the lesions may reflect carcinoma of the lung or, possibly, prostate. This represents one of the earliest cases of metastatic carcinoma worldwide and the oldest case documented thus far from Northeast Asia.     

Pamidronate in the treatment of bone metastases from breast cancer

Bone metastases afflict over 70% of patients with advanced breast cancer, resulting in impaired quality of life and significant clinical problems. Until appearance of the bisphosphonates there was no specific therapeutic treatment available to manage the symptoms of osteolytic bone metastases. Bisphosphonates are stable chemical analogues of pyrophosphate, and inhibit osteoclast-mediated bone resorption, the treatment is effective in reducing skeletal morbidity in breast cancer with fewer skeletal related events, reduced pain and analgesic consumption, and improved quality of life. As a result, bisphosphonates should now be part of the routine management of metastatic bone disease and multiple myeloma. Promising data have resulted in considerable interest in the possible adjuvant use of bisphosphonates. Pamidronate is an easy to use potent inhibitor of osteolysis, given in conjunction with standard anticancer therapies effectively relieves bone pain and improves performance status. Monthly pamidronate infusions for one or two years in addition to standard anticancer therapy reduce by more than one third the yearly frequency of skeletal-related events. The authors report their practice in which 119 breast cancer patients metastatic to bone received 90-120 mg pamidronate infusion/cycle in addition to standard breast cancer therapy every 3-4 weeks.     

A cellular solid model for modulus reduction due to resorption of trabeculae in bone

In osteoporotic trabecular bone, bone loss occurs by thinning and subsequent resorption of the trabeculae. In this study, we compare the effects of density reductions from uniform thinning of struts or from removal of struts in a random, open-cell, three-dimensional Voronoi structure. The results of this study, combined with those previous studies on other regular and random structures, suggest that the modulus and strength of trabecular bone are reduced more dramatically by density losses from resorption of trabeculae than by those from uniform thinning of trabeculae.     

Treatment of multiple myeloma with nasal spray calcitonin: a histomorphometric and biochemical study

To evaluate the effect of calcitonin on the bone lesions of multiple myeloma, we studied 11 patients treated for 3 months with salmon calcitonin in nasal spray (200 IU) and 500 mg of elemental calcium/day. Pre- and post-treatment biochemical and histomorphometric parameters were compared to those of 12 patients treated for the same time with 500 mg elemental calcium alone. Both groups received the same hematological treatment.In the group treated with calcitonin there was a significant increase (P < 0.01) in trabecular bone volume, cortical thickness, osteoid volume and osteoid seam thickness index and the osteoclast resorption surface fell significantly (P < 0.01). There was also a decline (P < 0.001) in corrected serum calcium and OHP/Cr, which accounts for the diminished bone resorption. The group not treated with calcitonin showed only significant changes in OHP/Cr which increase (P < 0.05).Calcitonin was perfectly tolerated by all patients and our results show it to be useful in the treatment of bone lesions of multiple myeloma.     

Clinical development of anti-RANKL therapy

The receptor activator of nuclear factor-kappaB ligand (RANKL), its cognate receptor RANK, and its natural decoy receptor osteoprotegerin have been identified as the final effector molecules of osteoclastic bone resorption. This has provided an ideal target for therapeutic interventions in metabolic bone disease. As described in previous reviews in this supplement, RANKL signaling is required for osteoclast differentiation, activation, and survival. Furthermore, in vivo inhibition of RANKL leads to immediate osteoclast apoptosis, and there are no in vivo models of bone resorption that are refractory to RANKL inhibition. Thus, the only step remaining in the development of a clinical intervention is the generation of a safe, effective, and specific drug that can inhibit RANKL in humans. Here we review the clinical development of denosumab (formerly known as AMG 162), which is a fully human mAb directed against RANKL. This discussion includes the breadth of 21 human studies that have led to the current phase 3 clinical trials seeking approval for use of this agent to treat postmenopausal women with low bone mineral density (osteoporosis) and patients with metastatic lytic bone lesions (multiple myeloma, and prostate and breast cancer).     

Intra-tibial injection of human prostate cancer cell line CWR22 elicits osteoblastic response in immunodeficient rats

We investigated the utility of CWR22 human prostate cancer cells for modeling human metastatic prostate cancer, specifically their ability to induce bone formation following intra-tibial injections in the nude rat. Prostate cancer is unique in regard to its tropism for bone and ability to induce new bone formation. In contrast to humans, other mammalian species rarely develop prostatic cancer spontaneously upon aging and do not have the propensity for bone metastasis that is the hallmark of cancer malignancy in men. We chose human prostate cancer cell line CWR22 based on its properties, which closely resemble all of the features that characterize the early stages of prostatic cancer in human patients including slow growth rate, hormone dependence/independence and secretion of prostate-specific antigen. When CWR22 cells were injected directly into the proximal tibia of immunodeficient male rats, both osteoblastic and osteolytic features became evident after 4 to 6 weeks, with elevated levels of serum prostate-specific antigen. However, osteosclerosis dominates the skeletal response to tumor burden. Radiological and histological evidence revealed osteosclerotic lesions with trabeculae of newly formed bone lined by active osteoblasts and surrounded by tumor cells. Toward the end of the 7-week study, osteolytic bone lesions become more evident on X-rays. Paraffin and immunohistochemical evaluations revealed mature bone matrix resorption as evidenced by the presence of many tartrate resistant acid phosphatase positive multinucleated osteoclasts. We conclude that the CWR22 human prostate cell line used in an intra-tibial nude rat model provides a useful system to study mechanisms involved in osteoblastic and osteolytic bony metastases. This type of in vivo model that closely mimics all major features of metastatic disease in humans may provide a critical tool for drug development efforts focused on developing integrated systemic therapy targeting the tumor in its specific primary or/and metastatic microenvironments. In addition to targeting bone marrow stroma, this strategy will help to overcome classical drug resistance seen at the sites of prostate cancer metastasis to bones.     

Role of osteoblast suppression in multiple myeloma

Multiple myeloma is the most common form of plasma cell dyscrasia and virtually all cases of myeloma exhibit osteolytic lesions, which result in bone pain, pathological fractures, spinal cord compression, and hypercalcaemia. Malignant plasma cells disrupt the delicate balance between bone formation and bone resorption, which ultimately leads to the debilitating osteolytic lesions. This review focuses principally on mechanisms of osteoblast inhibition by malignant plasma cells with emphasis placed on our experimental findings, which support a model for abnormal Wnt signaling in osteoblast suppression. We describe how excessive amounts of soluble Wnt inhibitors secreted by malignant plasma cells in multiple myeloma could promote osteolytic lesions, tumor growth, suppress hematopoiesis, prevent proper engraftment, and expansion of transplanted stem cells. Finally, we detail current therapies shown to disrupt the interaction between the myeloma cell and the microenvironment, leading to activation of osteoblasts.     

Alpha-smooth muscle actin is expressed in a subset of bone marrow stromal cells in normal and pathological conditions

A series of 217 trephine bone marrow biopsies from adult patients and specimens from 16 fetuses and 5 infants were examined for the presence of stromal myoid cells (MCs) using a monoclonal antibody recognizing alpha-smooth muscle actin. In the normal adult bone marrow, stromal cells did not contain alpha-smooth muscle actin, whereas during fetal life, many alpha-smooth muscle actin-containing MCs were connected with vascular sinusoids in the primitive bone marrow. This cell type reappeared in various characteristic distribution patterns in adult bone marrow during different neoplastic and non-neoplastic conditions including metastatic carcinoma, Hodgkin's disease, multiple myeloma, hairy cell leukemia, acute myeloid leukemia (FAB M4, 5, 7) and chronic myelo-proliferative diseases. In general, the appearance of MCs was associated with a slight to pronounced increase in the deposition of reticulin and collagen fibers. We propose that bone marrow MCs represent a distinct subpopulation of fiber-associated or adventitial reticular cells undergoing cytoskeletal remodeling in response to various stimuli.     

Tartrate-resistant acid phosphatase (TRAP) activity in serum: potential use in assessing bone resorption in patients with multiple myeloma

We measured serum tartrate-resistant acid phosphatase (TRAP) activity in 120 healthy subjects and 35 patients with multiple myeloma as well as urinary hydroxyproline excretion in the myeloma patients. Young subjects (0-18 years) showed higher TRAP levels (ANOVA p less than 0.01) compared with the other age classes due to the more active bone remodelling processes associated with growth. Myeloma patients with bone lytic lesions (MM+) showed higher serum TRAP values than controls (p less than 0.01). Hydroxyproline excretion was higher in MM+ patients but the difference between patients with and without bone lesions was not statistically significant. Our data suggest that serum TRAP activity may be a suitable, simple biochemical test to assess bone turnover in patients with multiple myeloma but that its clinical usefulness as a marker of bone resorption needs further evaluation.     

Pathogenesis of myeloma bone disease

Multiple myeloma (MM) is the most common cancer to involve bone with up to 90% of patients developing bone lesions. The bone lesions are purely osteolytic in nature and do not heal in the vast majority of patients. Up to 60% of patients develop pathologic fractures over the course of their disease. Bone disease is a hallmark of MM, and myeloma bone disease differs from bone metastasis caused by other tumors. Although myeloma and other osteolytic metastases induce increased osteoclastic bone destruction, in contrast to other tumors, once myeloma tumor burden exceeds 50% in a local area, osteoblast activity is either severely depressed or absent. The basis for this severe imbalance between increased osteoclastic bone resorption and decreased bone formation has been the topic of intensive investigation over the last several years. These studies have helped to identify novel targets for treating myeloma bone disease and will be discussed in this chapter. J. Cell. Biochem. 109: 283–291, 2010. © 2009 Wiley‐Liss, Inc.     

RANKL/RANK/OPG: new therapeutic targets in bone tumours and associated osteolysis

The emergence of the molecular triad osteoprotegerin (OPG)/Receptor Activator of NF-kB (RANK)/RANK Ligand (RANKL) has helped elucidate a key signalling pathway between stromal cells and osteoclasts. The interaction between RANK and RANKL plays a critical role in promoting osteoclast differentiation and activation leading to bone resorption. OPG is a soluble decoy receptor for RANKL that blocks osteoclast formation by inhibiting RANKL binding to RANK. The OPG/RANK/RANKL system has been shown to be abnormally regulated in several malignant osteolytic pathologies such as multiple myeloma [MM, where enhanced RANKL expression (directly by tumour cells or indirectly by stromal bone cells or T-lymphocytes)] plays an important role in associated bone destruction. By contrast, production of its endogenous counteracting decoy receptor OPG is either inhibited or too low to compensate for the increase in RANKL production. Therefore, targeting the OPG/RANK/RANKL axis may offer a novel therapeutic approach to malignant osteolytic pathologies. In animal models, OPG or soluble RANK was shown both to control hypercalcaemia of malignancy and the establishment and progression of osteolytic metastases caused by various malignant tumours. To this day, only one phase I study has been performed using a recombinant OPG construct that suppressed bone resorption in patients with multiple myeloma or breast carcinoma with radiologically confirmed bone lesions. RANK-Fc also exhibits promising therapeutic effects, as revealed in animal models of prostate cancer and multiple myeloma. If the animal results translate to similar clinical benefits in humans, using RANK-Fc or OPG may yield novel and potent strategies for treating patients with established or imminent malignant bone diseases and where standard therapeutic regimens have failed.     

α-Smooth muscle actin is expressed in a subset of bone marrow stromal cells in normal and pathological conditions

A series of 217 trephine bone marrow biopsies from adult patients and specimens from 16 fetuses and 5 infants were examined for the presence of stromal myoid cells (MCs) using a monoclonal antibody recognizing α-smooth muscle actin. In the normal adult bone marrow, stromal cells did not contain α-smooth muscle actin, whereas during fetal life, many α-smooth muscle actin-containing MCs were connected with vascular sinusoids in the primitive bone marrow. This cell type reappeared in various characteristic distribution patterns in adult bone marrow during different neoplastic and non-neoplastic conditions including metastatic carcinoma, Hodgkin’s disease, multiple myeloma, hairy cell leukemia, acute myeloid leukemia (FAB M4, 5, 7) and chronic myeloproliferative diseases. In general, the appearance of MCs was associated with a slight to pronounced increase in the deposition of reticulin and collagen fibers. We propose that bone marrow MCs represent a distinct subpopulation of fiber-associated or adventitial reticular cells undergoing cytoskeletal remodeling in response to various stimuli.     

Angiostatin inhibits bone metastasis formation in nude mice through a direct anti-osteoclastic activity

Bone is a very common metastatic site for breast cancer. In bone metastasis, there is a vicious circle wherein bone-residing metastatic cells stimulate osteoclast-mediated bone resorption, and bone-derived growth factors released from resorbed bone promote tumor growth. The contribution of tumor angiogenesis in the growth of bone metastases is, however, unknown. By using an experimental model of bone metastasis caused by MDA-MB-231/B02 breast cancer cells that quite closely mimics the conditions likely to occur in naturally arising metastatic human breast cancers, we demonstrate here that when MDA-MB-231/B02 cells were engineered to produce at the bone metastatic site an angiogenesis inhibitor, angiostatin, there was a marked inhibition in the extent of skeletal lesions. Inhibition of skeletal lesions came with a pronounced reduction in tumor burden in bone. However, although angiostatin produced by MDA-MB-231/B02 cells was effective at inhibiting in vitro endothelial cell proliferation and in vivo angiogenesis in a Matrigel implant model, we have shown that it inhibited cancer-induced bone destruction through a direct inhibition of osteoclast activity and generation. Overall, these results indicate that, besides its well known anti-angiogenic activity, angiostatin must also be considered as a very effective inhibitor of bone resorption, broadening its potential clinical use in cancer therapy.     

Bone cell interactions through Eph/ephrin

Bones cannot properly form or be maintained without cell-cell interactions through ephrin ligands and Eph receptors. Cell culture analysis and evaluation of genetic mouse models and human diseases reveal various ephrins and Eph functions in the skeletal system. Migration, attachment and spreading of mesenchymal stem cells are regulated by ephrinB ligands and EphB receptors. ephrinB1 loss-of-function is associated with craniofrontonasal syndrome (CFNS) in humans and mice. In bone remodeling, ephrinB2 is postulated to act as a “coupling stimulator.” In that case, bidirectional signaling between osteoclastic ephrinB2 and osteoblastic EphB4 suppresses osteoclastic bone resorption and enhances osteoblastic bone formation, facilitating the transition between these two states. Parathyroid hormone (PTH) induces ephrinB2 in osteoblasts and enhances osteoblastic bone formation. In contrast to ephrinB2, ephrinA2 acts as a “coupling inhibitor,” since ephrinA2 reverse signaling into osteoclasts enhances osteoclastogenesis and EphA2 forward signaling into osteoblasts suppresses osteoblastic bone formation and mineralization. Furthermore, ephrins and Ephs likely modulate pathological conditions such as osteoarthritis, rheumatoid arthritis, multiple myeloma and osteosarcoma. This review focuses on ephrin/Eph-mediated cell-cell interactions in bone biology.     

Geranylgeranyl transferase type II inhibition prevents myeloma bone disease

Geranylgeranyl transferase II (GGTase II) is an enzyme that plays a key role in the isoprenylation of proteins. 3-PEHPC, a novel GGTase II inhibitor, blocks bone resorption and induces myeloma cell apoptosis in vitro. Its effect on bone resorption and tumor growth in vivo is unknown. We investigated the effect of 3-PEHPC on tumor burden and bone disease in the 5T2MM model of multiple myeloma in vivo. 3-PEHPC significantly reduced osteoclast numbers and osteoclast surface. 3-PEHPC prevented the bone loss and the development of osteolytic bone lesions induced by 5T2MM myeloma cells. Treatment with 3-PEHPC also significantly reduced myeloma burden in bone. The magnitude of response was similar to that seen with the bisphosphonate, risedronate. These data show that targeting GGTase II with 3-PEHPC can prevent osteolytic bone disease and reduce tumor burden in vivo, and represents a novel approach to treating tumors that grow in bone.     

Consequences of daily administered parathyroid hormone on myeloma growth, bone disease, and molecular profiling of whole myelomatous bone

Background

Induction of osteolytic bone lesions in multiple myeloma is caused by an uncoupling of osteoclastic bone resorption and osteoblastic bone formation. Current management of myeloma bone disease is limited to the use of antiresorptive agents such as bisphosphonates.

Methodology/Principal Findings

We tested the effects of daily administered parathyroid hormone (PTH) on bone disease and myeloma growth, and we investigated molecular mechanisms by analyzing gene expression profiles of unique myeloma cell lines and primary myeloma cells engrafted in SCID-rab and SCID-hu mouse models. PTH resulted in increased bone mineral density of myelomatous bones and reduced tumor burden, which reflected the dependence of primary myeloma cells on the bone marrow microenvironment. Treatment with PTH also increased bone mineral density of uninvolved murine bones in myelomatous hosts and bone mineral density of implanted human bones in nonmyelomatous hosts. In myelomatous bone, PTH markedly increased the number of osteoblasts and bone-formation parameters, and the number of osteoclasts was unaffected or moderately reduced. Pretreatment with PTH before injecting myeloma cells increased bone mineral density of the implanted bone and delayed tumor progression. Human global gene expression profiling of myelomatous bones from SCID-hu mice treated with PTH or saline revealed activation of multiple distinct pathways involved in bone formation and coupling; involvement of Wnt signaling was prominent. Treatment with PTH also downregulated markers typically expressed by osteoclasts and myeloma cells, and altered expression of genes that control oxidative stress and inflammation. PTH receptors were not expressed by myeloma cells, and PTH had no effect on myeloma cell growth in vitro.

Conclusions/Significance

We conclude that PTH-induced bone formation in myelomatous bones is mediated by activation of multiple signaling pathways involved in osteoblastogenesis and attenuated bone resorption and myeloma growth; mechanisms involve increased osteoblast production of anti-myeloma factors and minimized myeloma induction of inflammatory conditions.     

Simulation of vertebral trabecular bone loss using voxel finite element analysis

Trabecular bone loss in human vertebral bone is characterised by thinning and eventual perforation of the horizontal trabeculae. Concurrently, vertical trabeculae are completely lost with no histological evidence of significant thinning. Such bone loss results in deterioration in apparent modulus and strength of the trabecular core. In this study, a voxel-based finite element program was used to model bone loss in three specimens of human vertebral trabecular bone. Three sets of analyses were completed. In Set 1, strain adaptive resorption was modelled, whereby elements which were subject to the lowest mechanical stimulus (principal strain) were removed. In Set 2, both strain adaptive and microdamage mechanisms of bone resorption were included. Perforation of vertical trabeculae occurred due to microdamage resorption of elements with strains that exceeded a damage threshold. This resulted in collapse of the trabecular network under compression loading for two of the specimens tested. In Set 3, the damage threshold strain was gradually increased as bone loss progressed, resulting in reduced levels of microdamage resorption. This mechanism resulted in trabecular architectures in which vertical trabeculae had been perforated and which exhibited similar apparent modulus properties compared to experimental values reported in the literature. Our results indicate that strain adaptive remodelling alone does not explain the deterioration in mechanical properties that have been observed experimentally. Our results also support the hypothesis that horizontal trabeculae are lost principally by strain adaptive resorption, while vertical trabeculae may be lost due to perforation from microdamage resorption followed by rapid strain adaptive resorption of the remaining unloaded trabeculae.     

Metastatic breast carcinoma in cerebrospinal fluid. A cytomorphometric study

A study was undertaken to quantitate the cellular characteristics of metastatic breast carcinoma in cerebrospinal fluid (CSF). Millipore filters of CSF from 15 patients with metastatic breast carcinoma were reviewed; 50 cells per case were evaluated when available. All cells in all cases shed singly or in loose clusters; tight balls or morulae were absent. All cells had regular, round-to-oval nuclei with finely granular chromatin. The majority of cells in all cases had single or multiple round nucleoli, granular cytoplasm with distinct borders and a mean nuclear-cytoplasmic ratio of close to 0.70. Cellular background, number of tumor cells per case, number and placement of nuclei and nuclear and cytoplasmic diameter varied both within and among the cases. There was significant variation in nuclear and cytoplasmic diameters both within and among the cases of infiltrating ductal carcinoma. Thus, the uniform appearance of the cells was due to consistent cytologic features, not to similarity in cell size. The cytologic profile of metastatic breast carcinoma is sufficiently characteristic to distinguish this tumor from other benign and malignant lesions that shed in the CSF.