Search

The proteasome is a proteolytic complex for intracellular degradation of ubiquitinated proteins which are involved in cell-cycle regulation and apoptosis. A constitutively increased proteasome activity has been found in myeloma cells. We studied circulating proteasome levels and their prognostic significance in sera of 50 control subjects, 20 persons with monoclonal gammopathies of undetermined significance (MGUS), and 141 previously untreated patients with multiple myeloma (MM) by an anti-20S proteasome enzyme-linked immunoabsorbent assay (ELISA). Serum proteasome concentrations were significantly elevated in MM compared with controls (P < .001), in MM versus MGUS (P = .03), and in active (n = 101) versus smoldering (n = 40) MM (P < .001). In patients with active MM, there was a significant (P < .001) decrease from pretreatment to post-treatment proteasome concentrations in responders to chemotherapy, but not in nonresponders. Circulating proteasome levels were identified as a prognostic factor for overall survival in the univariate (P < .001 log-rank test) and in the multivariate (hazard ratio, 4.38) survival analysis in patients with active MM. We demonstrate for the first time that increased serum proteasome concentrations correlate with advanced disease and are an independent prognostic factor in MM.

The 26S proteasome is a multicatalytic intracellular protease expressed in eukaryotic cells. It is responsible for selective degradation of intracellular proteins that are responsible for cell proliferation, growth, regulation of apoptosis and transcription of genes involved in execution of key cellular functions. Thus proteasome inhibition is a potential treatment option for cancer and diseases due to aberrant inflammation condition. Treatment with proteasome inhibitors results in stabilization and accumulation proteasome substrates, a phenomenon that may result in confounding signals in cells, cell cycle arrest and activation of apoptotic programs. The inhibition of the transcriptional factor nuclear factor kappaB (NF-kappaB) activation was found as one of crucial mechanisms in induction of apoptosis, overcoming resistance mechanisms and inhibition of immune response and inflammation mechanisms. Bortezomib (PS-341) and PS-519 are the first proteasome inhibitors that have entered clinical trials. In multiple myeloma, both the FDA (United States Food and Drug Administration) and EMEA (European Medicine Evaluation Agency) granted an approval for the use of bortezomib (Velcade) for the treatment of relapsed multiple myeloma. At present, several phase II and phase III trials in hematological malignancies and solid tumors are ongoing. PS-519 that focuses on inflammation, reperfusion injury and ischemia is currently under evaluation for the indication of acute stroke.

The proteasome is a multicatalytic threonine protease responsible for intracellular protein turnover in eukaryotic cells, including the processing and degradation of several proteins involved in cell cycle control and the regulation of apoptosis. Preclinical studies have shown that the treatment with proteasome inhibitors results in decreased proliferation, induction of apoptosis, and sensitization of tumor cells against conventional chemotherapeutic agents and irradiation. The effects were conferred to stabilization of p21, p27, Bax, p53, I-KB, and the resulting inhibition of the nuclear factor-KB (NF-KB) activation. Bortezomib is the first proteasome inhibitor that has entered clinical trials. In multiple myeloma, both the FDA (United States Food and Drug Administration) and EMEA (European Medicine Evaluation Agency) granted an approval for the use of bortezomib (Velcade, Millennium Pharmaceuticals, Cambridge, MA, USA) for the treatment of relapsed multiple myeloma. At present, clinical trials are examining the activity in a variety of solid tumors and hematological malignancies.

Objectives: Myeloma bone disease is a result of excessive osteoclast activation and impaired osteoblast function. Recent in vitro studies suggested that proteasome inhibitors might increase osteoblast function., Methods: We analyzed serum markers of osteoblast activity in 25 patients with multiple myeloma receiving bortezomib alone or in combination with dexamethasone. As control, serum samples from 58 consecutive myeloma patients receiving a therapy different than bortezomib (i.e. adriamycin/dexamethasone, melphalan/prednisone or thalidomide) were evaluated. The serum concentrations of bone-specific alkaline phosphatase (BAP) and osteocalcin were quantified before initiation of treatment and after 3 months., Results: In patients treated with bortezomib, mean serum levels of osteocalcin significantly increased from 6.3 to 10.8 microg/L (P = 0.024), while mean BAP levels increased from 19.7 to 30.2 U/L (P < 0.0005). Of interest, the increase in BAP was significant both in responders and non-responders. In contrast, the control group did not show a statistically significant change in BAP (24.8 U/L vs. 23.3 U/L) and osteocalcin (6.8 microg/L vs. 6.5 microg/L) before and after the treatment., Conclusion: These data show that treatment with bortezomib leads to enhanced markers of osteoblast activity in patients with myeloma. The comparison with the control group suggests that the effect on osteoblasts is unique to the proteasome inhibitor.

Peroxisome proliferator-activated receptor-gamma, a nuclear receptor and transcription factor, and its natural and synthetic ligands have become a focus of novel approaches to induction of apoptosis in solid tumors and hematologic malignancies, including malignant B-lineage cells. The effect on mantle cell lymphoma, a subtype with dismal prognosis, has not yet been analyzed. We investigated the effect of 15-deoxy-delta-12,14-prostaglandin J2 (15d-PGJ2), pioglitazone (PGZ) or rosiglitazone (RGZ) on human mantle cell lymphoma cell lines (GRANTA-519, Hbl-2 and JeKo-1). Mantle cell lymphoma cell lines exhibited a high expression of Peroxisome proliferator-activated receptor-gamma protein in Western blot analysis. MTT assays revealed anti-proliferative effects induced by both 15d-PGJ2, the natural activator of Peroxisome proliferator-activated receptor-gamma, and PGZ and RGZ, synthetic Peroxisome proliferator-activated receptor-gamma ligands, in a dose-dependent manner. At a dose of 50 micromol/l, 15d-PGJ2 induced growth inhibition in all cell lines. The anti-proliferative effect of PGZ and RGZ was slightly lower. Induction of apoptosis was indicated by annexin V staining. At a dose of 50 micromol/l, 15d-PGJ2 led to apoptosis in all cell lines (87-99%) after 48 h of incubation. Again, the apoptotic effect with thiazolidinediones was slightly lower at the same dose level. This is the first study evaluating Peroxisome proliferator-activated receptor-gamma expression and its therapeutic implications in human mantle cell lymphoma cells. Thiazolidinediones comprise anti-lymphoma activity in vitro and should be further explored for the treatment of mantle cell lymphoma.

Bone disease, a hallmark of multiple myeloma occurs in the majority of the patients, is associated with bone pain, fractures, hypercalcemia and has major impacts on quality of life. Myeloma is characterized by a unique form of bone disease with osteolytic bone destruction that is not followed by reactive bone formation, resulting in extensive lytic lesions. This review will focus on the pathophysiology of osteoclast activation and osteoblast inhibition in multiple myeloma and on biochemical markers of bone turnover. Since osteolytic lesions do not rapidly heal in myeloma, X-rays cannot reflect the activity of bone disease during antimyeloma treatment. Activity in bone turnover does not parallel changes in monoclonal protein levels. Thus, there is a need for biochemical markers reflecting disease activity in bone. The utility, prognostic implications and limitations of classical and novel markers of bone remodeling (e.g. ICTP, NTx, TRACP-5b, osteoprotegerin, sRANKL) will be discussed in this overview.

Multiple myeloma (MM) was the first haematological malignancy in which a prognostic relevance of bone marrow microvessel density (MVD) was shown. Myeloma-induced angiogenesis involves either the direct production of angiogenic molecules by myeloma cells or their induction in bone marrow stromal cells or endothelial cells (EC). Recent data demonstrate an increased angiogenic potential and a paracrine stimulatory effect of bone marrow EC on plasma cells (PC) in MM. Soluble angiogenic factors are elevated in bone marrow (BM) and in peripheral blood samples from myeloma patients. Furthermore, correlation with disease stage and prognosis was shown for serum levels of the angiogenic factors basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF). In this review we summarize recent data which give strong evidence for an increased angiogenic activity in bone marrow microenvironment and support the hypothesis that angiogenesis is not only an epiphenomenon of tumour growth but may also promote PC growth in MM.

The aim of this study was to evaluate the effects of valproic acid (VPA), as a histone deacetylase inhibitor, on myeloma cell lines and on sorted human bone marrow multiple myeloma cells. VPA induced accumulation of acetylated histones, potently inhibited proliferation in a dose-dependent manner and induced apoptosis in all myeloma cell lines tested as well as in sorted primary multiple myeloma cells. Cell cycle analysis indicated an arrest in G0/1 phase in response to VPA. Accumulation of p21 and reduced levels of cyclin D1 were detected. The production of vascular endothelial growth factor was significantly inhibited by VPA. These results provide the framework for clinical trials.

Objectives: Mantle cell lymphoma (MCL) is an incurable disease with an aggressive course and novel treatment strategies are urgently needed. The purpose of this study was to evaluate the effects of histone deacetylase (HDAC) inhibitors, a new group of antiproliferative agents, on human MCL cells., Methods: Three MCL cell lines (JeKo-1, Hbl-2 and Granta-519) were exposed to different concentrations of the HDAC inhibitors sodium butyrate (NaB) and suberoylanilide hydroxamic acid (SAHA) for 8-72 h. Their effects on cell viability, apoptosis induction and cell cycle proliferation were studied. Moreover, the influence of SAHA on the expression of cyclin D1, the cell cycle regulators p21 and p27 and the production of vascular endothelial growth factor (VEGF) were analyzed., Results: The HDAC inhibitors induced accumulation of acetylated histones in MCL cells. MTT assays and Annexin-V staining showed that they potently inhibited viability in a dose-dependent manner and induced apoptosis in all cell lines tested. Cell cycle analysis indicated that their exposure to SAHA or NaB decreased the proportion of cells in S phase and increased the proportion of cells in the G0/G1 and/or G2/M phases. Incubation with the two HDAC inhibitors resulted in downregulation of cyclin D1. SAHA lead to an upregulation of p21 in all cell lines and an upregulation of p27 in JeKo-1 and Granta-519 cells, while expression of p27 in Hbl-2 was not altered. In addition, SAHA inhibited the production of the angiogenic cytokine VEGF. Treatment with NaB increased the expression of p21 in JeKo-1 and Hbl-2 cells, while in Granta 519 cells no effect was noted. The expression of p27 remained constant in all three cell lines after exposure to NaB., Conclusion: Based on these findings, we provide evidence that HDAC inhibitors have antiproliferative effects in MCL and may represent a promising therapeutic approach.

Increased bone resorption is a major characteristic of multiple myeloma and is caused by osteoclast activation and osteoblast inhibition (uncoupling). Myeloma cells alter the local regulation of bone metabolism by increasing the receptor activator of NF-kappaB ligand (RANKL) and decreasing osteoprotegerin expression within the bone marrow microenvironment, thereby stimulating the central pathway for osteoclast formation and activation. In addition, they produce the chemokines MIP-1alpha, MIP-1beta, and SDF-1alpha, which also increase osteoclast activity. On the other hand, myeloma cells suppress osteoblast function by the secretion of osteoblast inhibiting factors, e.g., the Wnt inhibitors DKK-1 and sFRP-2. Moreover, they inhibit differentiation of osteoblast precursors and induce apoptosis in osteoblasts. The resulting bone destruction releases several cytokines, which in turn promote myeloma cell growth. Therefore, the inhibition of bone resorption could stop this vicious circle and not only decrease myeloma bone disease, but also the tumor progression.

Cancer-induced bone disease results in bone destruction, pathological fractures, and pain. We hypothesized that the inhibition of the proteasome-ubiquitin system in osteoclasts could abolish the receptor activator of NF-kappaB ligand (RANKL) mediated osteoclast differentiation and function, since RANKL-mediated downstream signaling plays a crucial role in osteoclast life cycle. In this study, we examined the effects of the proteasome inhibitors MG-132 and MG-262 on RANKL-induced osteoclast differentiation and function. Osteoclast precursors from peripheral blood mononuclear cells were cultured in the presence of RANKL and M-CSF. Osteoclasts were identified as multi-nucleated TRAP-positive cells. Osteoclast function was quantified with the extent of dentine resorption and TRAP activity in culture supernatants. For the evaluation of the effects of proteasome inhibitors towards osteoclastogenesis, sub-apoptotic concentrations of MG-132 and MG-262 were used. Effects on NF-kappaB were obtained in treated and untreated osteoclasts. MG-132 and MG-262 inhibit both osteoclast differentiation and osteoclast function. 0.01 microM MG-132 induced a 3.2-fold (P = 0.004) and 0.001 microM MG-262 a 3.3-fold (P = 0.004) reduction of osteoclast differentiation, respectively. The resorption capacity was decreased 2.6- and 11.1-fold (P = 0.003) by treatment with 0.01 and 0.1 microM MG-132, and 14.2- and 16.6-fold (P = 0.003) by 0.001 and 0.01 microM MG-262, respectively. This decrease correlated with the extent of NF-kappaB binding capacity. In conclusion, this study shows for the first time that proteasome inhibitors act on osteoclast development and function at low concentrations and should be considered as potential drugs for the treatment of cancer-induced osteolytic bone disease.

Proteasome inhibitors represent novel anti-cancer drugs which interact with the proteasome-ubiquitin pathway. The 26S proteasome is a multicatalytic threonine protease with three distinct catalytic activities. It is responsible for intracellular protein turnover in eukaryotic cells, including the processing and degradation of short- and some long-living proteins required for regulation of various cellular functions. Subsequently, the inhibition of the proteasomal function results in stabilization and accumulation of its substrates, which notably include cyclins, cyclin-dependent kinase inhibitors, transcriptional factors, tumor suppressor proteins and proto-oncogenes. This results in confounding signals in the cell inducing cell cycle arrest and activation of apoptotic programs. Acting on transcriptional factor NF-kappaB, which is upregulated in some tumors undergoing chemotherapy or irradiation and downregulated by proteasome inhibition, a significant chemosensitization and consequently synergistic effects concerning the anti-tumor activity could be achieved. Bortezomib is the first proteasome inhibitor that has entered clinical trials. In multiple myeloma, both the US Food and Drug Administration and European Medicine Evaluation Agency granted approval for the use of bortezomib (Velcade) for the treatment of multiple myeloma patients who have received at least two prior therapies and have demonstrated disease progression on the last therapy. At present, other trials examine the activity in a variety of solid tumors and hematological malignancies. This paper reviews preclinical and clinical results.

The activation of proliferator-activated receptor gamma (PPAR-gamma) by its natural and synthetic ligands induces apoptosis in several tumor cell lines, including malignant B-lineage cells. We investigated whether treatment with pioglitazone (PGZ), rosiglitazone (RGZ) or 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) inhibited tumor cell growth in five human multiple myeloma cell lines (LP-1, U-266, RPMI-8226-S, OPM-2 and IM-9) and human bone marrow myeloma cells expressing PPAR-gamma protein. MTT assays revealed growth arrest induced by the natural activator of PPAR-gamma 15d-PGJ2 and a lower antiproliferative effect with thiazolidinediones (PGZ and RGZ) in a dose-dependent manner. Induction of apoptosis was indicated by Annexin-V staining. At a dose of 50 microM, 15d-PGJ2 led to a high rate of apoptosis in all cell lines (60-92%). Furthermore, induction of apoptosis in sorted bone marrow plasma cells from myeloma patients was detected. Thiazolidinediones comprise anti-myeloma activity in vitro and should be explored further for the treatment of multiple myeloma.

Purpose: Increased bone resorption is a hallmark of multiple myeloma and a result of excessive osteoclast activation. Recently, the receptor activator of NF-kappaB ligand (RANKL) was found to be the critical factor for osteoclastogenesis. Studies showed that myeloma cells induce RANKL expression in bone marrow stromal cells, but it remained a controversy whether myeloma cells directly express RANKL., Methods: Therefore, we analyzed the expression of RANKL mRNA in freshly isolated CD138 positive plasma cells from patients with multiple myeloma and osteolytic bone lesions, using three different primer pairs against human RANKL., Results: RANKL mRNA could be detected in bone marrow plasma cells from myeloma patients with osteolytic myeloma bone disease., Conclusions: These findings show that myeloma cells directly express RANKL and indicate that specific blockade of RANKL may be an effective treatment for myeloma bone disease.

Campath-1H, a monoclonal antibody against human CD52, is used for the therapy of refractory or relapsed chronic lymphocytic leukemia (CLL). Treatment with campath is associated with an increased incidence of infections and also fatal reactivation of viral infections. Reactivation of hepatitis B virus (HBV) in HBsAg-positive patients is a well-documented complication of cytotoxic or immunosuppressive therapy and has also been observed after treatment with rituximab. To date, there are no reports on campath treatment in HBsAg carriers. Here, we present the case of a patient with heavily pretreated CLL who was HBsAg-positive with a high virus load (>2 billion copies/mL). He required treatment because of progressive CLL with massive bone marrow infiltration, severe anemia and thrombocytopenia. Campath was initiated and lamivudine, an inhibitor of reverse transcriptase, was simultaneously given to prevent HBV proliferation. During the treatment, no deterioration of liver parameters was observed, and the virus load decreased. After therapy with campath, hemoglobin and platelet counts increased markedly. This report shows that lamivudine is highly effective in inhibiting HBV proliferation and can be used to prevent HBV flare-up during campath treatment in patients tested positive for HBs antigen.

Liposomal daunorubicin replacing conventional anthracyclines may reduce toxicity and enhance efficacy of chemotherapy. In this phase I study, we evaluated liposomal daunorubicin (DaunoXome) in combination with vincristine and dexamethasone for toxicity, pharmacokinetics and potential efficacy in patients with multiple myeloma. The main objective was to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of liposomal daunorubicin combined with vincristine and dexamethasone (VLDD). Additionally, pharmacokinetics were determined at higher dose levels. Seventeen multiple myeloma patients were enrolled in this trial; 76% of the patients had relapsed or refractory multiple myeloma. Successive cohorts received liposomal daunorubicin at doses of 40, 60, 80 and 100 mg/m2 on day 1 in combination with vincristine 1.4 mg/m2 (day 1) and oral dexamethasone (40 mg, days 1-4). DLT occurred at 100 mg/m2. Liposomal daunorubicin at 80 mg/m2 was well tolerated in this protocol and should be used for further phase II studies with the VLDD regimen. In this phase I trial, 64% of the patients achieved a partial remission or a minor response.

Purpose: Skeletal involvement is a hallmark of multiple myeloma. Increased bone resorption can even be present in patients lacking osteolyses in conventional radiography. Magnetic resonance imaging (MRI) of the spine was established as a more sensitive technique to depict bone abnormalities. Type-I collagen degradation product carboxyterminal telopeptide of type-I collagen (ICTP) was introduced as a novel biochemical parameter reflecting the bone resorption activity in myeloma. The aim of this study was to evaluate whether increased ICTP serum levels predict abnormal MRI patterns in myeloma patients., Experimental Design: MRI of the spine was performed in 32 untreated patients with multiple myeloma, who had no skeletal abnormalities in conventional radiographies. Simultaneously, ICTP was measured in serum by a competitive radioimmunoassay at corresponding time points., Results: Serum ICTP was significantly (P = 0.002) elevated in patients with abnormal bone MRI compared with those patients with normal MRI findings. The sensitivity of ICTP for depiction of MRI abnormalities was 79%; the positive and negative predictive values were 85 and 84%, respectively. Compared with ICTP, the parameters of disease activity, beta2-microglobulin and C-reactive protein, had a much lower sensitivity for abnormal MRI (29 and 64%, respectively)., Conclusions: In myeloma patients without osteolytic lesions in conventional radiography, abnormal skeletal MRI is accompanied by an increase in serum levels of ICTP. Our data show that ICTP can be used as an inexpensive parameter to identify myeloma patients with normal skeletal survey who have a high probability of skeletal involvement and deserve more accurate diagnostic evaluation using MRI.

Purpose: In this study, we investigated the effects of cell-permeable proteasome inhibitors MG-132, MG-262, PSI, and lactacystin on multiple myeloma cell lines OPM-2, U266, RPMI 8226-S, freshly isolated plasma cells with or without deletion of chromosome 13 from patients with multiple myeloma and plasma cell leukemia, and CD34+ human hematopoietic stem cells. The effects of proteasome inhibitors on cell cycle progression, cell growth, and apoptosis were determined., Methods: MTT-assay was used to examine the cytotoxicity, and annexin-V staining to quantify apoptosis. Cell cycle analyses were performed using 7-ADD and Ki-67 staining by flow cytometry., Results: PSI was the most potent proteasome inhibitor among those tested with a half maximal cytotoxicity (IC(50)) of 5.7 nM, followed by MG-262, MG-132, and lactacystin. Growth inhibition occurred irrespective of chromosome 13 status. Cell cycle arrest occurred in a dose- and time-dependent manner. Low, subapoptotic dosages led to a partial loss of Ki-67 antigen, whereas apoptotic dosages led to reduced Ki-67 levels. Apoptosis was partially dependent on activation of caspase-3, since Ac-DEVD-cho, a caspase-3 inhibitor, could reduce apoptosis significantly. The cytotoxicity of the four proteasome inhibitors tested was significantly lower in human hematopoietic stem cells than in myeloma cells., Conclusions: Our results show that proteasome inhibitors induce time- and dose-dependent cell cycle alterations, growth inhibition, and apoptosis in human myeloma cells irrespective of chromosome 13 deletion.

Purpose: Increased bone resorption is a hallmark of multiple myeloma and is attributable to osteoclast activation. Recent studies showed that the receptor activator of nuclear factor kappaB ligand (RANKL) is the key mediator of osteoclastogenesis and plays a crucial role in bone destruction in malignant bone disease. We found that human myeloma cells express RANKL and analyzed the association of the RANKL expression with the presence of osteolytic bone disease in patients with multiple myeloma., Experimental Design: Flow cytometry was performed on bone marrow samples derived from controls and multiple myeloma patients with or without osteolytic bone lesions on conventional radiography. Plasma cells were identified as CD38++/CD138+ cells. The level of RANKL expression on the surface of bone marrow plasma cells was correlated with the bone status of the patients., Results: The bone marrow plasma cells from controls showed no or only a weak surface expression of RANKL, and the median mean fluorescence index (MFI) was 6. In contrast, expression of RANKL could be detected on bone marrow plasma cells from all of the patients with multiple myeloma, and median MFI was 47. The difference in MFI for RANKL expression of bone marrow plasma cells from controls and myeloma patients was highly significant (P < 0.0005). Myeloma patients with osteolytic bone lesions showed a significantly higher expression of RANKL (median MFI = 60; range, 16-2494) compared with patients without osteolysis (median MFI = 16; range, 6-229; P < 0.0005)., Conclusions: These results show for the first time that the level of RANKL expression by myeloma cells correlates significantly with osteolytic bone disease.

Purpose: We studied bone marrow angiogenesis in different stages of multiple myeloma according to the Durie and Salmon classification and its correlations with other disease characteristics., Methods: Sixty-five immunohistochemical CD34-stained, paraffin-embedded bone marrow biopsies of multiple myeloma patients and 12 controls were studied. The mean number of microvessels per area in each sample was determined as the microvessel density (MVD). In addition, plasma cell infiltration of the bone marrow, serum beta2-microglobulin, immunoglobulin levels, C-reactive protein, and serum calcium concentration were measured in 22 patients with stage I multiple myeloma and in 43 patients in stage II-III., Results: In myeloma patients, the bone marrow MVD was significantly higher than in controls (P<0.001). In 43 patients with stage II-III multiple myeloma, MVD was significantly higher than in 22 patients with stage I (median MVD 46 and 21 vessels/mm(2), respectively, P=0.005). Additionally, in stage II-III the bone marrow MVD correlated positively with the bone marrow plasma cell infiltration (r=0.55, P<0.001) and the serum beta2-microglobulin level (r=0.53, P<0.001), while in stage I patients no correlation could be found., Conclusions: Angiogenesis is significantly increased in stage II-III myeloma in comparison to stage I. In stages II-III, bone marrow angiogenesis is correlated with plasma cell infiltration and serum beta2-microglobulin levels.

Myeloma bone disease is due to interactions of myeloma cells with the bone marrow microenvironment, and is associated with pathologic fractures, neurologic symptoms and hypercalcemia. Adjacent to myeloma cells, the formation and activation of osteoclasts is increased, which results in enhanced bone resorption. The recent characterization of the essential cytokine of osteoclast cell biology, receptor activator of NF-kappa B ligand (RANKL) and its antagonist osteoprotegerin (OPG), have led to a detailed molecular and cellular understanding of myeloma bone disease. Myeloma cells induce RANKL expression in bone marrow stromal cells, and direct RANKL expression by myeloma cells may contribute to enhanced osteoclastogenesis in the bone microenvironment in myeloma bone disease. Furthermore, myeloma cells inhibit production and induce degradation of OPG. These effects result in an increased RANKL-to-OPG ratio that favors the formation and activation of osteoclasts. Patients with myeloma bone disease have inappropriately low serum and bone marrow levels of OPG. Specific blockade of RANKL prevented the skeletal complications in various animal models of myeloma, and suppressed bone resorption in a preliminary study of patients with myeloma bone disease.

Skeletal morbidity is a major problem in multiple myeloma. Histomorphometric studies have demonstrated that increased bone resorption can be present even in the absence of radiographic abnormalities. To overcome diagnostic problems in estimating the activity of bone resorption, new laboratory parameters that reflect bone metabolism accurately are urgently needed. We analyzed three parameters of osteoclastic bone destruction, i.e. deoxypyridinoline (Dpd) and amino-terminal collagen type-I telopeptide (NTx) in urine and carboxy-terminal telopeptide of type-I collagen (ICTP) in serum, of 75 patients with multiple myeloma (n = 57) or monoclonal gammopathy of undetermined significance (MGUS, n = 18) by ELISA/RIA techniques. Serum ICTP and urinary Dpd levels increased parallel to the stage of the disease and differed significantly (P < 0.001 for ICTP and P = 0.03 for Dpd) between MGUS, myeloma stage I, and myeloma in stages II and III according to Salmon and Durie. ICTP and Dpd were significantly elevated in patients with multiple myeloma in stage I compared to individuals with MGUS, while no significant difference was found for NTx. In this first study comparing the prognostic relevance of ICTP, NTx, and Dpd in multiple myeloma patients, ICTP was found to be a prognostic factor for overall survival in the Kaplan-Meier analysis (log-rank test: P < 0.03). Urinary NTx showed borderline significance (P = 0.05), and Dpd had no prognostic value in the survival analysis. Our data show that serum ICTP and urinary Dpd levels increase in parallel to advanced disease stages, and gives the first report on a significant difference in the bone resorption parameters ICTP and Dpd between individuals with MGUS and patients with myeloma in stage I. Among the bone resorption parameters studied serum ICTP was found to be the best prognostic factor for survival in multiple myeloma.

There is growing evidence that angiogenesis is important not only in solid tumors but also in hematological malignancies. Recently, we found that bone marrow angiogenesis is a prognostic factor for disease-related survival in patients with multiple myeloma. In this report, we addressed the question of whether the microvessel density in bone marrow biopsies is correlated to other myeloma parameters, e.g., serum beta2-microglobulin (beta2-MG) and plasma cell infiltration in the bone marrow. In 22 multiple myeloma patients, immunohistochemical, CD34-stained, paraffin-embedded bone marrow biopsies before and after chemotherapy were studied. Microvessels were counted in 400x magnification, and the mean number of vessels per area in each sample was noted as the microvessel density (MVD). Pretreatment bone marrow MVD (median: 44, range: 11-175 vessels/mm2) correlated significantly with the bone marrow plasma cell infiltration (median: 30%, range: 5-90%, r = 0.642, P=0.001) and beta2-MG (median: 2.74, range: 1.4-26.1 mg/l, r = 0.749, P < 0.0005). In contrast, there was no correlation between posttreatment MVD and plasma cell infiltration or beta2-MG (median: MVD 31, range: 0-221 vessels/mm2, median plasma cell infiltration: 15%, range: 5-80%, r = 0.229, P = 0.306 and median beta2-MG: 2.65, range: 1-27.6 mg/l, r = -0.042, P = 0.853). These findings show that the strong correlations between bone marrow MVD and plasma cell infiltration as well as serum beta2-MG levels disappear after chemotherapy. The underlying mechanisms need further investigations.

Background and Objectives: The differential diagnosis between multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) may be uncertain in some cases; this problem is reflected by discrepancies between different classification systems with an accordance in only 2/3 of cases. We studied whether flow-cytometric characteristics of plasma cells (PC) can be used for the differentiation between MGUS and MM., Design and Methods: Patients were divided into 3 groups: Group A included 13 myeloma patients with a plasma cell infiltration of the bone marrow of 10-30%, serum M-protein < or = 3.5 g/dL (IgG) or < or = 2 g/dl (IgA) and without bone lesions in conventional radiography. Group B consisted of 53 patients who fulfilled the Durie and Salmon diagnostic criteria including at least one major criterion, and group C individuals with MGUS (n=17). The ratio of immunophenotypically normal (i.e. CD19(+)/CD56(-)) to all bone marrow plasma cells (BMPC), the number of peripheral blood PC (PBPC), the percentage of BMPC in S-phase and the DNA content of BMPC were analyzed., Results: All individuals with MGUS and no patient with MM in group A or group B had a ratio of phenotypically normal to all BMPC > or = 20%. The median of monoclonal PBPC was 0/microL (range 0-2/ microL) in MGUS, 1/microL (range 0-30/microL) in MM group A and 2.4/microL (range 0-211/microL) in MM group B. The median percentage of BMPC in S-phase was 1.6% both in MGUS and in group A and 3% in group B. Aneuploidy was found in 12%, 11% and 41% in MGUS, group A and group B, respectively., Interpretation and Conclusions: The ratio of immunophenotypically normal to all BMPC was the only flow-cytometric parameter for the differentiation of MGUS and MM group A (p<0.0005). The other parameters were significantly different between MGUS and MM group B, but not group A.

The impact of angiogenesis is well known for the growth and viability of solid tumors. Fewer studies have been published relating angiogenesis to clinical or pathological parameters in hematological malignancies. In this report, we have estimated the bone marrow microvessel density (MVD) before and after conventional-dose or high-dose chemotherapy with autologous stem cell transplantation. Immunohistochemical CD34-stained paraffin-embedded bone marrow biopsies of 21 patients with stage III multiple myeloma were studied. Microvessels were counted at 400x magnification, and the mean number of vessels per area in each sample was noted as the MVD. The median MVD of all patients was 53.1 vessels/mm2 (range 15.5-174.7 vessels/mm2) before treatment and 29.3 vessels/mm2 (range 0-221.1 vessels/mm2) after chemotherapy. The post-treatment MVD in the two groups of patients with and without remission was significantly different (p=0.001), whereas the pretreatment MVD was not. Responders but not nonresponders showed a significant decrease of MVD after therapy in comparison to their pretreatment levels. The progression-free survival in patients who achieved a reduction in MVD after chemotherapy was significantly longer than in patients without a decrease in MVD (P=0.006). Furthermore, we compared the MVD of patients after achievement of a remission to MVD of 15 untreated stage I myeloma patients. The MVD of patients in remission was not statistically different from the MVD in stage I myeloma. These results underscore the impact of angiogenesis in myeloma and give the first report that effective chemotherapy is accompanied by a significant decrease in bone marrow angiogenesis in this disease.

The importance of neoangiogenesis for the progressive growth and viability of solid tumors is well established. Recently, there has been growing evidence that angiogenesis might also be important in hematological malignancies, but only few data are available. In this report, we have studied the impact of bone marrow microvessel density and survival in patients with multiple myeloma (MM). Immunohistochemical CD34 stained paraffin-embedded bone marrow biopsies of 44 patients with newly diagnosed MM were studied. Microvessels were counted in 400 x magnification and the mean number of vessels per area in each sample was noted as the microvessel density (MVD). The median MVD was 48 vessels/mm2, the range was 0-125 vessels/mm2. Using a cut-off value of the median MVD in the Kaplan-Meier analysis, the median survival was 22.2 months in the group with the higher MVD and was not reached in the group with the lower MVD (P< 0.01). In a multivariate Cox regression analysis, using previously identified prognostic factors beta2-microglobulin, C-reactive protein (CRP), and age, MVD remained significant as a prognostic factor (P< 0.03).