Enhanced production of osteopontin in multiple myeloma: clinical and pathogenic implications

Role of Extracellular Vesicle-Based Cell-to-Cell Communication in Multiple Myeloma Progression

Multiple myeloma (MM) progression closely depends on the bidirectional crosstalk between tumor cells and the surrounding microenvironment, which leads to the creation of a tumor supportive niche. Extracellular vesicles (EVs) have emerged as key players in the pathological interplay between the malignant clone and near/distal bone marrow (BM) cells through their biologically active cargo. Here, we describe the role of EVs derived from MM and BM cells in reprogramming the tumor microenvironment and in fostering bone disease, angiogenesis, immunosuppression, drug resistance, and, ultimately, tumor progression. We also examine the emerging role of EVs as new therapeutic agents for the treatment of MM, and their potential use as clinical biomarkers for early diagnosis, disease classification, and therapy monitoring.

Salivary Osteopontin as a Potential Biomarker for Oral Mucositis

Osteopontin (OPN), a multifunctional phosphoglycoprotein also presents in saliva, plays a crucial role in tumour progression, inflammation and mucosal protection. Mucosal barrier injury due to high-dose conditioning regimen administered during autologous and allogeneic peripheral stem cell transplantation (APSCT) has neither efficient therapy nor established biomarkers. Our aim was to assess the biomarker role of OPN during APSCT, with primary focus on oral mucositis (OM). Serum and salivary OPN levels were determined by ELISA in 10 patients during APSCT at four stages of transplantation (day -3/-7, 0, +7, +14), and in 23 respective healthy controls. Results: There was a negative correlation between both salivary and serum OPN levels and grade of OM severity during APSCT (r = -0.791, p = 0.019; r = -0.973, p = 0.001). Salivary OPN increased at days +7 (p = 0.011) and +14 (p = 0.034) compared to controls. Among patients, it was higher at day +14 compared to the time of admission (day -3/-7) (p = 0.039) and transplantation (day 0) (p = 0.011). Serum OPN remained elevated at all four stages of transplantation compared to controls (p = 0.013, p = 0.02, p = 0.011, p = 0.028). During APSCT elevated salivary OPN is a potential non-invasive biomarker of oral mucositis whereas the importance of high serum OPN warrants further studies.

Game of Bones: How Myeloma Manipulates Its Microenvironment

Multiple myeloma is a clonal disease of long-lived plasma cells and is the second most common hematological cancer behind Non-Hodgkin's Lymphoma. Malignant transformation of plasma cells imparts the ability to proliferate, causing harmful lesions in patients. In advanced stages myeloma cells become independent of their bone marrow microenvironment and form extramedullary disease. Plasma cells depend on a rich array of signals from neighboring cells within the bone marrow for survival which myeloma cells exploit for growth and proliferation. Recent evidence suggests, however, that both the myeloma cells and the microenvironment have undergone alterations as early as during precursor stages of the disease. There are no current therapies routinely used for treating myeloma in early stages, and while recent therapeutic efforts have improved patients' median survival, most will eventually relapse. This is due to mutations in myeloma cells that not only allow them to utilize its bone marrow niche but also facilitate autocrine pro-survival signaling loops for further progression. This review will discuss the stages of myeloma cell progression and how myeloma cells progress within and outside of the bone marrow microenvironment.

The extracellular matrix: A key player in the pathogenesis of hematologic malignancies

Hematopoietic stem and progenitor cells located in the bone marrow lay the foundation for multiple lineages of mature hematologic cells. Bone marrow niches are architecturally complex with specific cellular, physiochemical, and biomechanical factors. Increasing evidence suggests that the bone marrow microenvironment contributes to the pathogenesis of hematological neoplasms. Numerous studies have deciphered the role of genetic mutations and chromosomal translocations in the development hematologic malignancies. Significant progress has also been made in understanding how the cellular components and cytokine interactions within the bone marrow microenvironment promote the evolution of hematologic cancers. Although the extracellular matrix is known to be a key player in the pathogenesis of various diseases, it's role in the progression of hematologic malignancies is less understood. In this review, we discuss the interactions between the extracellular matrix and malignant cells, and provide an overview of the role of extracellular matrix remodeling in sustaining hematologic malignancies.

Multiple myeloma-A painful disease of the bone marrow

Multiple myeloma is a bone marrow neoplasia with an incidence of 6/100,000/year in Europe. While the disease remains incurable, the development of novel treatments such as autologous stem cell transplantation, proteasome inhibitors and monoclonal antibodies has led to an increasing subset of patients living with long-term myeloma. However, more than two thirds of patients suffer from bone pain, often described as severe, and knowledge on the pain mechanisms and its effect on their health-related quality of life (HRQoL) is limited. In this review, we discuss the mechanisms of myeloma bone disease, the currently available anti-myeloma treatments and the lessons learnt from clinical studies regarding HRQoL in myeloma patients. Moreover, we discuss the mechanisms of cancer-induced bone pain and the knowledge that animal models of myeloma-induced bone pain can provide to identify novel analgesic targets. To date, information regarding bone pain and HRQoL in myeloma patients is still scarce and an effort should be made to use standardised questionnaires to assess patient-reported outcomes that allow inter-study comparisons of the available clinical data.

A Patient with Non-alcoholic Steatohepatitis Complicated by Multiple Myeloma

A 68-year-old woman with liver dysfunction was diagnosed with nonalcoholic steatohepatitis (NASH) stage 1. Three years later, she showed massive ascites and jaundice. A trans-jugular liver biopsy confirmed advanced cirrhosis, suggesting that her liver fibrosis had progressed rapidly. At the same time, she was diagnosed with multiple myeloma (MM). In this case, the plasma levels of osteopontin (OPN), a proinflammatory cytokine that promotes liver fibrosis progression through the hedgehog pathway and is increased in patients with MM, were increased. This increased OPN expression was accompanied by the upregulation of the hedgehog pathway in this patient, suggesting that the MM-associated increase in OPN had promoted the progression of liver fibrosis through the hedgehog pathway. The progression of liver fibrosis should be monitored in patients with NASH if other diseases, such as MM, are present.

Prognostic Biomarkers in the Progression From MGUS to Multiple Myeloma: A Systematic Review

Multiple myeloma (MM), characterized by malignant plasma cells in the bone marrow, is consistently preceded by asymptomatic premalignant stage monoclonal gammopathy of undetermined significance (MGUS). These MGUS patients have an annual risk of 1% to progress to MM. Clinical, imaging, and genomic (genetic and epigenetic) factors were identified, whose presence increased the risk of progression from MGUS to MM. In this systematic review we summarize the currently identified clinical, imaging, and genomic biomarkers suggested to increase the progression risk or shown to be differentially expressed/present between both cohorts of patients. Despite the wide range of proposed markers, there are still no reliable biomarkers to individually predict which MGUS patient will progress to MM and which will not. Research on biomarkers in the progression from MGUS to MM will give more insight in the unknown pathogenesis of this hematological malignancy. This would improve research by elucidating new pathways and potential therapeutic targets as well as clinical management by closer follow-up and earlier treatment of high-risk MGUS patients.

Plasma Osteopontin Level as a Diagnostic Marker of Hepatocellular Carcinoma in Patients with Radiological Evidence of Focal Hepatic Lesions

Aims

Hepatocellular carcinoma is one of the most aggressive malignant tumors and has limited treatment options. Needle-guided biopsies have been utilized as a tool to diagnose malignant focal hepatic lesions. These techniques are discouraged because of their complications. Nowadays, alpha fetoprotein is the most widely used tumor marker for screening and diagnosis of hepatocellular carcinoma. Nevertheless, this marker has limitations. The diagnostic role of plasma osteopontin as an adjuvant or alternative marker to alpha fetoprotein to detect hepatocellular carcinoma in Egyptian patients with focal hepatic lesions was evaluated in this study.

Subject and methods

Eighty participants were recruited from the Egyptian National Liver Institute and were self-assigned to three groups, namely, focal hepatic lesions (n = 40), liver cirrhosis (n = 20), and controls (n = 20). Participants' plasma osteopontin and serum alpha fetoprotein levels were determined and were compared across the three groups.

Results

The discriminatory ability of plasma osteopontin for hepatocellular carcinoma was lower than that of alpha fetoprotein. Osteopontin and alpha fetoprotein were not correlated with each other. Neither the gender nor the age of the patients showed a significant association with plasma osteopontin level.

Conclusion

Measuring plasma osteopontin level alone has no advantage over serum alpha fetoprotein in patients with focal hepatic lesions due to chronic liver disease.

Pathogenesis of bone disease in multiple myeloma: from bench to bedside

Osteolytic bone disease is the hallmark of multiple myeloma, which deteriorates the quality of life of myeloma patients, and it affects dramatically their morbidity and mortality. The basis of the pathogenesis of myeloma-related bone disease is the uncoupling of the bone-remodeling process. The interaction between myeloma cells and the bone microenvironment ultimately leads to the activation of osteoclasts and suppression of osteoblasts, resulting in bone loss. Several intracellular and intercellular signaling cascades, including RANK/RANKL/OPG, Notch, Wnt, and numerous chemokines and interleukins are implicated in this complex process. During the last years, osteocytes have emerged as key regulators of bone loss in myeloma through direct interactions with the myeloma cells. The myeloma-induced crosstalk among the molecular pathways establishes a positive feedback that sustains myeloma cell survival and continuous bone destruction, even when a plateau phase of the disease has been achieved. Targeted therapies, based on the better knowledge of the biology, constitute a promising approach in the management of myeloma-related bone disease and several novel agents are currently under investigation. Herein, we provide an insight into the underlying pathogenesis of bone disease and discuss possible directions for future studies.

Osteopontin and their roles in hematological malignancies: Splice variants on the new avenues

Osteopontin (OPN) is a protein expressed in several tissues, including bone marrow, in which it performs distinct roles, such as modulating hematopoietic stem cell niche and bone remodeling. Most data in hematological malignancies (HMs) refers to total OPN (tOPN), comprehending the sum of distinct OPN splicing isoforms (OPN-SI), while reports describing the expression and roles of each OPN-SI are scarce. This review aims to summarize tOPN roles in HMs and provide evidence that OPN-SIs can also modulate specific functions in HMs biology. We summarize that upregulated tOPN can modulate HMs (leukemia, lymphoma and myeloma) progression, inducing cell adhesion, invasion, angiogenesis, cell differentiation and extramedullary and/or central nervous system infiltration. Based on this expression pattern, tOPN has been pointed out as a biomarker in those HMs, thus providing potential targets for therapeutic approaches. Our group found that OPN-SIs are expressed in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cell lines (unpublished data), providing early evidence that OPN-SIs are also expressed in BCP-ALL. Further studies should investigate whether these OPN-SIs can differently modulate HMs biology and their putative application as auxiliary biomarkers for HMs.

Prognostic significance of osteopontin in acute myeloid leukemia: A meta-analysis

Osteopontin (OPN) has been investigated in the field of tumor research for several years. However, the prognostic role of OPN overexpression in acute myeloid leukemia (AML) remains controversial. A meta-analysis of four studies, including a total of 492 patients, was performed to determine the association of OPN with overall survival (OS) in AML patients. The random-effects model of Der Simonian and Laird was used to synthesize data; hazard ratio (HR) with its 95% confidence interval (CI) was used as the effect size estimate. It was observed that serum-based OPN was inversely correlated with OS and the difference was statistically significant (HR=1.83; 95% CI: 1.43-2.35; P<0.001). Experimental findings indicate that OPN overexpression is associated with a poor prognosis in AML and may be of prognostic value for AML stage and metastasis.

Matricellular proteins as regulators of cancer metastasis to bone

Metastasis is the major cause of death in cancer patients, and a frequent site of metastasis for many cancers is the bone marrow. Therefore, understanding the mechanisms underlying the metastatic process is necessary for future prevention and treatment. The tumor microenvironment is now known to play a role in the metastatic cascade, both at the primary tumor and in metastatic sites, and includes both cellular and non-cellular components. The extracellular matrix (ECM) provides structural support and signaling cues to cells. One particular group of molecules associated with the ECM, known as matricellular proteins, modulate multiple aspects of tumor biology, including growth, migration, invasion, angiogenesis and metastasis. These proteins are also important for normal function in the bone by regulating bone formation and bone resorption. Recent studies have described a link between some of these proteins and metastasis of various tumors to the bone. The aim of this review is to summarize what is currently known about matricellular protein influence on bone metastasis. Particular attention to the contribution of both tumor cells and non-malignant cells in the bone has been given.

Myeloma cell-derived Runx2 promotes myeloma progression in bone

The progression of multiple myeloma (MM) is governed by a network of molecular signals, the majority of which remain to be identified. Recent studies suggest that Runt-related transcription factor 2 (Runx2), a well-known bone-specific transcription factor, is also expressed in solid tumors, where expression promotes both bone metastasis and osteolysis. However, the function of Runx2 in MM remains unknown. The current study demonstrated that (1) Runx2 expression in primary human MM cells is significantly greater than in plasma cells from healthy donors and patients with monoclonal gammopathy of undetermined significance; (2) high levels of Runx2 expression in MM cells are associated with a high-risk population of MM patients; and (3) overexpression of Runx2 in MM cells enhanced tumor growth and disease progression in vivo. Additional studies demonstrated that MM cell-derived Runx2 promotes tumor progression through a mechanism involving the upregulation of Akt/β-catenin/Survivin signaling and enhanced expression of multiple metastatic genes/proteins, as well as the induction of a bone-resident cell-like phenotype in MM cells. Thus, Runx2 expression supports the aggressive phenotype of MM and is correlated with poor prognosis. These data implicate Runx2 expression as a major regulator of MM progression in bone and myeloma bone disease.

Plasma levels of osteopontin and vascular endothelial growth factor in association with clinical features and parameters of tumor burden in patients with multiple myeloma

The aim of this pilot study was to determine the plasma levels of osteopontin (OPN) and vascular endothelial growth factor (VEGF) and find possible association between them and main clinical features and parameters of tumor burden in patient with multiple myeloma (MM). Plasma levels of OPN and VEGF were determined in 44 newly diagnosed MM patients and 24 healthy persons by ELISA method. These values were compared with the presence of anemia, renal dysfunction, and bone lesions as myeloma related clinical manifestations and with serum beta-2 microglobulin and Durie-Salmon clinical stage as prognosticators related to tumor mass. The value of OPN was significantly higher in MM patients with evident bone lesions (P = 0.03) and there was also a positive correlation with serum beta-2 microglobulin (r = 0.366; P = 0.04). Furthermore, patients with lower Durie-Salmon stage had significantly lower OPN and VEGF levels (P = 0.05; P = 0.04, resp.). Our preliminary results found positive association between plasma level of OPN, tumor burden, and bone destruction. Further analysis should provide information about the possible use of OPN as useful clinical biomarker for monitoring bone disease and tumor mass, as well as a prognostic factor, or a possible target for pharmacological intervention.

Osteopontin is a prognostic factor for survival of acute myeloid leukemia patients

Osteopontin (OPN) is a glycoprotein that is secreted by osteoblasts and hematopoietic cells. OPN suppresses the proliferation of hematopoietic stem cells in vitro and may regulate the hematopoietic stem cell pool. Increased serum OPN concentrations occur in chronic myeloid leukemia, multiple myeloma, and acute myeloid leukemia (AML). In the present study, we analyzed the prognostic impact of OPN in AML by investigating the expression and relevance of OPN in newly diagnosed AML patients from 2 large study groups (the German AML Cooperative Group and the Dutch-Belgian Hematology Oncology Cooperative group). IHC (n = 84), ELISAs of blood/BM sera (n = 41), and microarray data for mRNA levels (n = 261) were performed. Expression of OPN protein was increased in AML patients both in BM blasts (IHC) and in BM serum (ELISA) compared with healthy controls. Patients expressing high levels of OPN within the BM (IHC) experienced shortened overall survival (OS; P = .025). Multivariate analysis identified karyotype, blast clearance (day 16), and the level of OPN expression as independent prognostic factors for OS. This prompted us to analyze microarray data from 261 patients from a third cohort. The analysis confirmed OPN as a prognostic marker. In summary, high OPN mRNA expression indicated decreased event-free survival (P = .0002) and OS (P = .001). The prognostic role of OPN was most prominent in intermediate-risk AML. These data provide evidence that OPN expression is an independent prognostic factor in AML.

Prognostic value of hepatocyte growth factor, syndecan-1, and osteopontin in multiple myeloma and monoclonal gammopathy of undetermined significance

Our aim was to compare serum levels of selected biological parameters in different phases of multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) to determine their diagnostic and prognostic potential. A cohort of 234 individuals was assessed for serum levels of hepatocyte growth factor (HGF), syndecan-1/CD₁₃₈ (SYN), and osteopontin (OPN). The patients with MM (N = 156) were divided into 3 groups: at the time of diagnosis (N = 45), in relapse/progression (N = 56), and in remission (N = 50). The analysis revealed significant differences of all three parameters in comparison of active and remission phase MM. Moreover, the parameters in active myeloma were significantly higher than in MGUS. Within the comparison of active disease (newly diagnosed and relapsing), there was no significant difference. Similar results were in remission phase MM and MGUS. There was no relationship of pretreatment levels of the parameters to therapeutic response. We conclude that serum levels of HGF, OPN, and SYN correspond to the activity of MM and might become useful in differentiation of MGUS, asymptomatic MM, and overt/symptomatic form of MM. The levels of all three parameters behave accordingly with MM activity. Pretreatment measurement without the assessment of their kinetics, however, has no relationship to therapeutic response.

Emerging strategies for targeting cell adhesion in multiple myeloma

Multiple myeloma (MM) is an incurable hematological cancer involving proliferation of abnormal plasma cells that infiltrate the bone marrow (BM) and secrete monoclonal antibodies. The disease is clinically characterized by bone lesions, anemia, hypercalcemia, and renal failure. MM is presently treated with conventional therapies like melphalan, doxorubicin, and prednisone; or novel therapies like thalidomide, lenalidomide, and bortezomib; or with procedures like autologous stem cell transplantation. Unfortunately, these therapies fail to eliminate the minimal residual disease that remains persistent within the confines of the BM of MM patients. Mounting evidence indicates that components of the BM-including extracellular matrix, cytokines, chemokines, and growth factors-provide a sanctuary for subpopulations of MM. This co-dependent development of the disease in the context of the BM not only ensures the survival and growth of the plasma cells but contributes to de novo drug resistance. In addition, by fostering homing, angiogenesis, and osteolysis, this crosstalk plays a critical role in the progression of the disease. Not surprisingly then, over the past decade, several strategies have been developed to disrupt this communication between the plasma cells and the BM components including antibodies, peptides, and inhibitors of signaling pathways. Ultimately, the goal is to use these therapies in combination with the existing antimyeloma agents in order to further reduce or abolish minimal residual disease and improve patient outcomes.

Pre- and post-translational regulation of osteopontin in cancer

Osteopontin (OPN) is a matricellular protein that binds to a number of cell surface receptors including integrins and CD44. It is expressed in many tissues and secreted into body fluids including blood, milk and urine. OPN plays important physiological roles in bone remodeling, immune response and inflammation. It is also a tumour-associated protein, and elevated OPN levels are associated with tumour formation, progression and metastasis. Research has revealed a promising role for OPN as a cancer biomarker. OPN is subject to alternative splicing, as well as post-translational modifications such as phosphorylation, glycosylation and proteolytic cleavage. Functional differences have been revealed for different isoforms and post-translational modifications. The pattern of isoform expression and post-translational modification is cell-type specific and may influence the potential role of OPN in malignancy and as a cancer biomarker.

Role of the metastasis-promoting protein osteopontin in the tumour microenvironment

Osteopontin (OPN) is a secreted protein present in bodily fluids and tissues. It is subject to multiple post-translational modifications, including phosphorylation, glycosylation, proteolytic cleavage and crosslinking by transglutamination. Binding of OPN to integrin and CD44 receptors regulates signalling cascades that affect processes such as adhesion, migration, invasion, chemotaxis and cell survival. A variety of cells and tissues express OPN, including bone, vasculature, kidney, inflammatory cells and numerous secretory epithelia. Normal physiological roles include regulation of immune functions, vascular remodelling, wound repair and developmental processes. OPN also is expressed in many cancers, and elevated levels in patients’ tumour tissue and blood are associated with poor prognosis. Tumour growth is regulated by interactions between tumour cells and their tissue microenvironment. Within a tumour mass, OPN can be expressed by both tumour cells and cellular components of the tumour microenvironment, and both tumour and normal cells may have receptors able to bind to OPN. OPN can also be found as a component of the extracellular matrix. The functional roles of OPN in a tumour are thus complex, with OPN secreted by both tumour cells and cells in the tumour microenvironment, both of which can in turn respond to OPN. Much remains to be learned about the cross-talk between normal and tumour cells within a tumour, and the role of multiple forms of OPN in these interactions. Understanding OPN-mediated interactions within a tumour will be important for the development of therapeutic strategies to target OPN.

Osteopontin deficiency impairs wear debris-induced osteolysis via regulation of cytokine secretion from murine macrophages

OBJECTIVE

To investigate the molecular mechanisms underlying particle-induced osteolysis, we focused on osteopontin (OPN), a cytokine and cell-attachment protein that is associated with macrophage chemoattractant and osteoclast activation.

METHODS

We compared OPN protein levels in human periprosthetic osteolysis tissues with those in osteoarthritis (OA) synovial tissues. To investigate the functions of OPN during particle-induced osteolysis in vivo, titanium particles were implanted onto the calvaria of OPN-deficient mice and their wild-type (WT) littermates. Mice were killed on day 10 and evaluated immunohistologically. The effects of OPN deficiency on the secretion of inflammatory cytokines were examined using cultured bone marrow-derived macrophages (BMMs). BMMs from OPN-deficient and WT mice were cultured with titanium particles for 12 hours, and the concentrations of inflammatory cytokines in the conditioned media were measured by enzyme-linked immunosorbent assay.

RESULTS

Expression of OPN protein was enhanced in human periprosthetic osteolysis tissues as compared with OA synovial tissues. In the particle-induced model of osteolysis of the calvaria, bone resorption was significantly suppressed by OPN deficiency via inhibition of osteoclastogenesis, whereas an inflammatory reaction was observed regardless of the genotype. Results of immunostaining indicated that OPN protein was highly expressed in the membrane and bone surface at the area of bone resorption in WT mice. When BMMs were exposed to titanium particles, the concentration of proinflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1alpha (IL-1alpha), IL-1beta, and IL-6, as well as chemotactic factors, such as monocyte chemoattractant protein 1 and macrophage inflammatory protein 1alpha, in the conditioned medium were significantly reduced by OPN deficiency. Whereas phagocytic activity of BMMs was not attenuated by OPN deficiency, phagocytosis-mediated NF-kappaB activation was impaired in OPN-deficient BMMs. These data indicated that OPN was implicated in the development of particle-induced osteolysis via the orchestration of pro-/antiinflammatory cytokines secreted from macrophages.

CONCLUSION

OPN plays critical roles in wear debris-induced osteolysis, suggesting that OPN is a candidate therapeutic target for periprosthetic osteolysis.

Genomic aberrations in hepatocellular carcinoma related to osteopontin expression detected by array-CGH

PURPOSE

We have demonstrated that overexpression of osteopontin (OPN) could contribute to metastasis in hepatocellular carcinoma (HCC), and that OPN-positive cancer cells are often localized in the periphery of cancer nodules adjacent to stromal cells. This study was to identify the difference of intratumor genomic aberrations between OPN-positive and OPN-negative HCC cells.

METHODS

Immunohistochemical staining for OPN was performed in both archival and fresh HCC tumor tissues. Seven cases of OPN-positive HCC were chosen for laser capture microdissection. The OPN-positive and OPN-negative cancer cells were captured separately from serial frozen sections. Genomic DNA was extracted and quantified. Microarray-based comparative genomic hybridization (array-CGH) was used to achieve high-resolution analysis of whole-genome-wide aberrations.

RESULTS

The OPN expression level in HCC tissues was significantly associated with vascular or bile duct invasion (P = 0.003), Edmondson's grade (P = 0.047), and intrahepatic spreading (P = 0.011). When compared with the OPN-negative cancer cells, much more amplifications of chromosomal regions, including 4q13.1-q13.3, 4q21.23-q22.1, and 13q32.1-q32.3, were found in OPN-positive HCC cells. Some candidate tumor-related genes, such as SMR3B, MUC7, EPHA5, SPP1, and CLDN10 were detected with over 1.5-fold amplification.

CONCLUSIONS

There is a significant intratumor genomic heterogeneity between the OPN-positive and negative HCC cells, and OPN-positive HCC cells play a more important role in the development of HCC malignancy than their OPN-negative counterparts.

Role of osteopontin in breast cancer patients

AIM AND BACKGROUND

In breast cancer, as in almost all neoplastic diseases, the prognosis is strictly related to the invasive capacity, local and distant, that characterizes the growth of all tumors. Since the mechanisms that regulate replication of the neoplastic cells, with consequent capacity to metastasize, are not completely known, identification of new markers represents the gold standard of research in the stratification of patients with such a pathology. Osteopontin, a specific phosphoglycoprotein isolated from extracellular bone matrix and actively involved in mechanisms of bone reabsorption, appears to play a key role in osteoclastogenesis at the level of the skeleton in some pathologic situations. It has been found that patients with metastatic bone lesions from breast or prostate cancer present, with respect to subjects without repetitive bone lesions, elevated serum levels of the protein, indicating that osteopontin could play an important role in the development and progression of the neoplastic disease at the bone level.

METHODS AND STUDY DESIGN

The authors studied 26 patients with breast cancer, evaluating as a marker also serum osteopontin levels.

RESULTS AND CONCLUSIONS

The results, although obtained on a small number of patients, showed that osteopontin evaluation in breast cancer patients can be a particularly interesting method of research in staging of the disease as well as in the prognosis, thereby attributing a role of a biotumoral marker also in the follow-up of the therapy.

Small integrin-binding ligand N-linked glycoproteins (SIBLINGs): multifunctional proteins in cancer

Numerous components and pathways are involved in the complex interplay between cancer cells and their environment. The family of glycophosphoproteins comprising osteopontin, bone sialoprotein, dentin matrix protein 1, dentin sialophosphoprotein and matrix extracellular phosphoglycoprotein - small integrin-binding ligand N-linked glycoproteins (SIBLINGs) - are emerging as important players in many stages of cancer progression. From their detection in various human cancers to the demonstration of their key functional roles during malignant transformation, invasion and metastasis, the SIBLINGs are proteins with potential as diagnostic and prognostic tools, as well as new therapeutic targets.

Myeloma cell-osteoclast interaction enhances angiogenesis together with bone resorption: a role for vascular endothelial cell growth factor and osteopontin

PURPOSE

Similar to osteoclastogenesis, angiogenesis is enhanced in the bone marrow in myeloma in parallel with tumor progression. We showed previously that myeloma cells and osteoclasts are mutually stimulated to form a vicious cycle to lead to enhance both osteoclastogenesis and tumor growth. The present study was undertaken to clarify whether myeloma cell-osteoclast interaction enhances angiogenesis and whether there is any mutual stimulation between osteoclastogenesis and angiogenesis.

EXPERIMENTAL DESIGN

Myeloma cells and monocyte-derived osteoclasts were cocultured, and angiogenic activity produced by the cocultures was assessed with in vitro vascular tubule formation assays and human umbilical vascular endothelial cell (HUVEC) migration and survival. Osteoclastogenic activity was determined with rabbit bone cell cultures on dentine slices.

RESULTS

Myeloma cells and osteoclasts constitutively secrete proangiogenic factors, vascular endothelial growth factor (VEGF) and osteopontin, respectively. A cell-to-cell interaction between myeloma cells and osteoclasts potently enhanced vascular tubule formation. Blockade of both VEGF and osteopontin actions almost completely abrogated such vascular tubule formation as well as migration and survival of HUVECs enhanced by conditioned medium from cocultures of myeloma cells and osteoclasts. Furthermore, these factors in combination triggered the production of osteoclastogenic activity by HUVEC.

CONCLUSIONS

Osteoclast-derived osteopontin and VEGF from myeloma cells cooperatively enhance angiogenesis and also induce osteoclastogenic activity by vascular endothelial cells. These observations suggest the presence of a close link between myeloma cells, osteoclasts, and vascular endothelial cells to form a vicious cycle between bone destruction, angiogenesis, and myeloma expansion.

Biochemical markers of bone turnover in diagnosis of myeloma bone disease

This study was designed to explore the value of markers of bone turnover, macrophage inflammatory protein-1alpha (MIP-1alpha), and osteopontin (OPN) in the diagnosis of myeloma bone disease. Twenty-five patients with newly diagnosed and untreated multiple myeloma (MM), and 22 age-, sex-, and bone mineral density-matched control subjects were enrolled. Levels of MIP-1alpha, OPN, carboxy-terminal telopeptide of Type-1 collagen (C-telopeptide or Ctx), deoxypyridinoline (DPD), Type-1 collagen propeptide (T1Pro), and bone-specific alkaline phosphatase (BALP) were assessed in both groups. Twenty-two of the patients had bone involvement documented by skeletal surveys and lumbar spinal magnetic resonance imaging. Levels of serum Ctx, OPN, MIP-1alpha, and urine DPD were significantly higher in MM patients with bone disease than in controls (P<0.01). Serum Ctx levels were elevated in 90.9% of patients with MM and 40.9% of controls (P<0.001). Urine DPD levels were elevated in 90.4% of the patients and 31.8% of the controls (P<0.001). The serum OPN and MIP-1alpha levels of the patients were significantly correlated with beta2-microglobulin and lactate dehydrogenase levels (P<0.05). Our study indicates that Ctx and DPD are sensitive markers of bone disease in MM, and higher than normal values suggest presence of bone disease rather than benign osteoporosis in MM. The utility of OPN and MIP-1alpha needs to be further investigated.

Osteopontin dysregulation and lytic bone lesions in multiple myeloma

Osteopontin (OPN), a secreted phosphoprotein involved in immune regulation and bone homeostasis, is a major component of bone, the natural habitat of long-lived plasma cells and multiple myeloma (MM). We show that only some MM cell lines and primary patient samples express OPN at high levels. High OPN expression inversely correlates with bone disease. When we subdivide MM into molecular subtypes, OPN is significantly upregulated in patients with maf translocations, particularly in the fraction lacking bone disease. OPN is produced in osteolytic lesions: we propose that MM-derived OPN plays a critical role in bone disease by protecting bone from destruction.

Osteopontin: a bridge between bone and blood

The production of mature blood cells within the bone marrow (BM) is attributed to a pool of haemopoietic stem cells (HSC). It is now evident that HSC reside preferentially at the endosteal region within the BM where bone-lining osteoblasts are a key cellular component of the HSC niche that directly regulates HSC fate. Osteoblasts synthesise proteins that stimulate and inhibit HSC proliferation. In addition to angiopoietin 1 (Ang-1), osteoblasts synthesise and express the highly acidic glycoprotein, osteopontin (Opn), which, like Ang-1, acts as a potent constraining factor on HSC proliferation. Overexpression of Opn is a feature of haemopoietic malignancies, such as multiple myeloma and chronic myeloid leukaemia, although its exact role in the aetiology and progression of these diseases remains unclear. Through osteoblasts and their cell surface and expressed proteins including Opn, bone is able to regulate the tissue that resides within it. In doing so, Opn can be considered a bridge between bone and blood.

Elevated plasma osteopontin levels in patients with hepatocellular carcinoma

OBJECTIVES

Osteopontin (OPN) is a secreted glycoprotein, frequently associated with various tumors. We investigated the usefulness of plasma OPN level as a biomarker for hepatocellular carcinoma (HCC).

METHODS

We determined plasma levels of OPN, alpha-fetoprotein (AFP), and prothrombin induced by vitamin K absence II (PIVKA II) in a group of 62 HCC patients, in 60 patients with chronic liver diseases, and in 60 healthy control individuals using a standardized ELISA kit. To determine the source of elevated plasma level of OPN, immunohistochemical analysis of 285 HCC samples on tissue microarray was performed.

RESULTS

Plasma OPN levels in the HCC patients (median 954 ng/mL, range 168-5,742) were significantly higher (p-value < 0.001) than those patients with chronic liver diseases (381 ng/mL, 29-1,688) or of a healthy control group (155 ng/mL, 10-766). Within the HCC patient group, plasma OPN level increased significantly with advancing degree of Child-Pugh class and of tumor stage. Diagnostic sensitivity and specificity of OPN for HCC was 87% and 82%, respectively (cut-off value: 617.6 ng/mL). OPN had a greater area under curve value (0.898) than AFP (0.745) or PIVKA II (0.578), suggesting superior diagnostic accuracy of OPN. Immunohistochemistry of 285 samples of HCC showed that OPN was expressed in 92 of 285 tumors (32.3%). OPN expression was found in the malignant hepatocytes and cancer-infiltrating macrophages, not in the noncancerous hepatocytes or Kupffer cells.

CONCLUSIONS

These data propose elevated plasma OPN levels as a potential biomarker for HCC.

Role of the integrin-binding protein osteopontin in lymphatic metastasis of breast cancer

Although a primary route of breast cancer metastasis is believed to be via lymphatics, the molecular factors involved are poorly understood. We hypothesized that one such factor may be the integrin-binding protein osteopontin (OPN), and we investigated this clinically and experimentally. In breast cancer patients undergoing sentinel lymph node biopsy, OPN levels were significantly higher in lymph node metastases than in the primary tumor (P < 0.001). To test the functional contribution of OPN to lymphatic metastasis and to determine whether the RGD (Arg-Gly-Asp) integrin-binding sequence of OPN is important for this process, we transfected wild-type OPN or mutant OPN (lacking the RGD sequence) into MDA-MB-468 human breast cancer cells. In vitro, cells overexpressing OPN demonstrated increased anchorage-independent growth in soft agar (P = 0.001) and increased RGD-dependent adhesion (P = 0.045). Following mammary fat pad injection of nude mice, cells overexpressing OPN showed increased lymphovascular invasion, lymph node metastases, and lung micrometastases at earlier time points (P = 0.024). Loss of the RGD region partially abrogated this effect in the lymphatics (P = 0.038). These novel findings indicate that OPN is a key molecular player involved in lymphatic metastasis of breast cancer, potentially by affecting RGD-mediated adhesive interactions and by enhancing the establishment/persistence of tumor cells in the lymphatics.

Angiogenesis in multiple myeloma

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 prognostic significance of preoperative plasma levels of osteopontin in patients with hepatocellular carcinoma

We aimed to evaluate the prognostic value of preoperative plasma osteopontin (OPN) levels in 101 patients with hepatocellular carcinoma (HCC) who underwent liver resection. Plasma OPN levels were detected by ELISA. The association of plasma OPN levels of patients with clinicopathological characteristics, tumor recurrence, and survival was analyzed. The median plasma OPN level of patients was 176.90 ng/ml (range 13.73-780.00 ng/ml), which was significantly higher than that of 24 healthy volunteers (63.74 ng/ml, range 12.20-122.32 ng/ml). Plasma OPN levels were significantly different in patients with different numbers of tumor nodules (168.18 and 217.11 ng/ml for single and multiple nodules, respectively; P = 0.002), different Edmondson's grades (201.24, 168.36, and 503.58 ng/ml for grades I, II, and III/IV, respectively; P = 0.015), and different TNM stages (168.16, 167.54, and 216.18 ng/ml for stages I, II, and III/IV, respectively; P = 0.016). Significantly higher plasma OPN levels were found in patients with a recurrence of HCC after resection, compared with those without recurrence (213.55 versus 153.70 ng/ml; P = 0.0013). A higher plasma OPN level was a leading independent prognostic factor for both overall survival (OS) and disease-free survival (DFS) in univariate and multivariate Cox models. This suggests that the preoperative plasma OPN level can be used as a predictive marker for HCC recurrence and may be helpful to assess the prognosis of patients with HCC after surgery.

Serial Plasma Osteopontin Levels Have Prognostic Value in Metastatic Breast Cancer

PURPOSE

Osteopontin is a malignancy-associated protein measurable in blood and tumor tissue. To evaluate its prognostic value in advanced disease, we conducted a prospective clinical study measuring serial osteopontin plasma levels in women with metastatic breast cancer throughout the course of their disease.

EXPERIMENTAL DESIGN

One hundred fifty-eight women with newly diagnosed metastatic breast cancer were enrolled in the study. Plasma osteopontin was measured using our validated ELISA, at baseline and every 3 to 12 weeks during and after therapy until death. Multivariate time-dependent survival analyses were conducted using models that right censored patient outcomes 3, 6, and 12 months after the last known osteopontin measurement.

RESULTS

Osteopontin was measured in 1,378 samples (median, 9 per patient). Ninety-nine patients had elevated baseline osteopontin (median, 177 ng/mL; range, 1-2,648 ng/mL). In univariate analysis, elevated baseline osteopontin was associated with short survival (P = 0.02). In a multivariate model incorporating standard prognostic factors, baseline osteopontin was significantly associated with survival duration (relative risk, 1.001; P = 0.038). Metastasis-free interval, visceral metastases, and Eastern Cooperative Oncology Group status 2 to 4 also retained significance. In a multivariate model incorporating standard prognostic factors and changes in sequential osteopontin levels, an osteopontin increase of >250 ng/mL at any time was the variable with the most prognostic value for poor survival (relative risk, 3.26; P = 0.0003), and poor Eastern Cooperative Oncology Group status also retained significance.

CONCLUSIONS

This is the first study to show that in women with metastatic breast cancer, increases in osteopontin levels over time are strongly associated with poor survival. Sequential monitoring of osteopontin may have use in making treatment decisions for these patients.

Osteopontin expression and serum levels in metastatic uveal melanoma: a pilot study

PURPOSE

This was a pilot study conducted to examine the expression of osteopontin in uveal melanoma and to determine whether serum osteopontin can be used in detecting metastatic uveal melanoma.

METHODS

Osteopontin mRNA was measured in three uveal melanoma cell lines of various invasive potential by real-time PCR. Tissue sections of primary and metastatic uveal melanomas were stained for osteopontin. Serum osteopontin levels were measured by ELISA assays in 15 patients with metastatic uveal melanoma and in 37 patients who were disease-free for at least 10 years after treatment of the primary tumor. Paired serum samples drawn from eight patients before and after development of metastasis were analyzed.

RESULTS

By real-time PCR, highly invasive primary and metastatic uveal melanoma cells expressed 6- and 250-fold excess osteopontin mRNA, respectively, compared with poorly invasive primary uveal melanoma cells. Tissue sections of primary uveal melanomas lacking looping vasculogenic mimicry patterns either did not stain for osteopontin or exhibited weak, diffuse staining. In primary melanomas containing looping vasculogenic mimicry patterns, strong osteopontin staining was detected in the tumor periphery where patterns were located. Diffuse strong expression of osteopontin was detected in eight samples of uveal melanomas metastatic to the liver. Serum osteopontin levels were significantly higher in patients with metastatic uveal melanoma than in patients who had been disease free for at least 10 years after treatment (P = 0.0001) or in age-matched control subjects. Serum osteopontin levels were significantly higher (P = 0.008) after metastasis than before the detection of metastasis in eight patients. When a cutoff of 10 ng/mL was used, the sensitivity and specificity of serum osteopontin in detecting metastatic melanoma was 87.5%, and the area under the receiver operator characteristic curve was 96%.

CONCLUSIONS

Osteopontin is expressed diffusely in tissue sections of hepatic metastases from uveal melanoma, and increased serum osteopontin levels correlate with melanoma metastasis to the liver with high specificity and sensitivity.

The involvement of osteopontin and its receptors in multiple myeloma cell survival, migration and invasion in the murine 5T33MM model

Multiple myeloma (MM) is a malignancy characterised by the accumulation of monoclonal plasma cells in the bone marrow. Different reports indicate the expression of CD44 variant isoforms (CD44v) by MM cells. Osteopontin (OPN), which is expressed by MM cells, is known to be a ligand for CD44v6. In this study, we investigated the role of OPN with emphasis on a functional correlation between OPN and CD44v in the 5T33MM model. Our group reported the expression of CD44v by 5T33MM cells. Using this model, we have demonstrated the secretion of OPN by 5T33MM cells. OPN affected 5T33MM cell survival by increasing proliferation and inhibiting apoptosis. OPN also stimulated 5T33MM cell migration, transendothelial migration and matrix metalloproteinase-9 activity. We confirmed the proliferative and migratory effects of OPN on human MM cells. By applying inhibiting anti-CD44v6 antibodies, we found that OPN stimulated cell proliferation by engaging this isoform. Anti-CD44v antibodies and RGD peptides both inhibited cell migration, suggesting an involvement of both, CD44v isoforms and integrins. In conclusion, OPN may act as a mediator of MM cell survival by engaging CD44v. The protein is further involved in migration and invasion of MM cells through the activation of either alphavbeta3 integrin or CD44v isoforms.

Human myeloma cells express the bone regulating gene Runx2/Cbfa1 and produce osteopontin that is involved in angiogenesis in multiple myeloma patients

Osteopontin (OPN) is a multifunctional bone matrix glycoprotein that is involved in angiogenesis, cell survival and tumor progression. In this study we show that human myeloma cells directly produce OPN and express its major regulating gene Runx2/Cbfa1. The activity of Runx2/Cbfa1 protein in human myeloma cells has also been demonstrated. Moreover, using small interfering RNA (siRNA) to silent Runx2 in myeloma cells, we suppressed OPN mRNA and protein expression. OPN production in myeloma cells was stimulated by growth factors as IL-6 and IFG-1 and in turn OPN stimulated myeloma cell proliferation. In an 'in vitro' angiogenesis system we showed that OPN production by myeloma cells is critical for the proangiogenic effect of myeloma cells. The expression of OPN by purified bone marrow (BM) CD138(+) cells has also been investigated in 60 newly diagnosed multiple myeloma (MM) patients, finding that 40% of MM patients tested expressed OPN. Higher OPN levels have been detected in the BM plasma of MM patients positive for OPN as compared to controls. Moreover, significantly higher BM angiogenesis has been observed in MM patients positive for OPN as compared to those negative. Our data highlight that human myeloma cells with active Runx2/Cbfa1 protein directly produce OPN that is involved in the pathophysiology of MM-induced angiogenesis.

The combination of intermediate doses of thalidomide with dexamethasone is an effective treatment for patients with refractory/relapsed multiple myeloma and normalizes abnormal bone remodeling, through the reduction of sRANKL/osteoprotegerin ratio

The aim of this study was the evaluation of the effect of intermediate doses of thalidomide with dexamethasone (Thal/Dex) on disease course and bone disease in patients with refractory/relapsed myeloma who were under zoledronic acid therapy. We studied 35 patients, who received thalidomide at a dose of 200 mg/daily. We measured, pre-, 3 and 6 months post-treatment soluble receptor activator of nuclear factor-kappaB ligand (sRANKL), osteoprotegerin (OPG), osteopontin (OPN), markers of bone resorption and formation. Before treatment, patients had increased levels of sRANKL/OPG ratio, bone resorption markers and OPN, while they had suppressed bone formation. The pretreatment sRANKL/OPG ratio correlated with the extent of bone disease. Thal/Dex administration resulted in a significant reduction of sRANKL/OPG ratio, and bone resorption. Bone formation, OPG and OPN did not show any alteration. Changes of sRANKL/OPG ratio correlated with changes of bone resorption markers. Thal/Dex was given for a median time of 10 months and the median follow-up period was 22 months. The response rate was 65.7%. The median survival was 19.5 months. beta2-microglobulin, type of response and International Staging System predicted for survival. These results suggest that the combination of intermediate dose of Thal/Dex is effective in patients with refractory/relapsed myeloma and improves abnormal bone remodeling through the reduction of sRANKL/OPG ratio.

Elevation of plasma osteopontin level in patients with undifferentiated nasopharyngeal carcinoma

AIMS

We evaluated the clinicopathologic relevance of plasma osteopontin (OPN) level in nasopharyngeal carcinoma patients.

METHODS

Seventy-two plasma samples were collected from patients with undifferentiated nasopharyngeal carcinoma (NPC) before radiotherapy. Plasma OPN level was determined by quantitative sandwich enzyme immunoassay. The plasma OPN level was evaluated for its clinicopathologic relevance.

RESULTS

The mean plasma OPN level was significantly higher in NPC patients than in normal controls (184.66 vs 75.89 ng/ml, p<0.001). In addition, high OPN level was found in the patients with advanced cancer and was correlated with neck node metastasis (p<0.05).

CONCLUSIONS

Our findings indicated a potential role of OPN in the pathogenesis and nodal metastasis of undifferentiated NPC.

Angiogenic switch in multiple myeloma

Angiogenesis is the hallmark of cancer. Growing evidence indicates that an imbalance between pro- and anti-angiogenic molecules triggers the angiogenic switch during tumor progression. Several molecules, able to affect vascular formation and function, are now beginning to be elucidated. Recent data indicate that angiogenesis also occurs in hematological malignancies. In multiple myeloma it has been demonstrated that patients with active disease have an increase in bone marrow angiogenesis correlated with the progression of disease and an adverse prognosis. The pathophysiology of myeloma-induced angiogenesis is complex and involves either the direct production of angiogenic molecules by myeloma cells or their induction in the microenvironment. In this review we have focalized our attention on the main factors involved in the angiogenic switch that occurs in MM patients.