Biomedical Sciences Human Oncology

In contrast to the pluripotentembryonic stem cells(ESCs) which are able to give rise to all cell types of the body, mammalianadult stem cells(ASCs) appeared to be more limited in their differentiation potential and to be committed to their tissue of origin. Recently, surprising new findings have contradicted central dogmas of commitment of ASCs by showing their plasticity to differentiate across tissue lineage boundaries, irrespective of classical germ layer designations. The present paper supports the plasticity of thebone marrow stem cells(BMSCs), bringing the most striking and the latest evidences of the transdifferentiation properties of thebone marrow hematopoietic and mesenchymal stem cells(BMHSCs, and BMMSCs), the two BM populations of ASCs better characterized. In addition, we report the possible mechanisms that may explain these events, outlining the clinical importance of these phenomena and the relative problems.

Tumor microenvironment is essential for multiple myeloma (MM) growth, progression, and drug resistance through provision of survival signals and secretion of growth and proangiogenic factors. This paper examines the importance of macrophages within MM bone marrow (BM) microenvironment, referred to as MM-associated macrophages, as a potential niche component that supports tumor plasma cells. These macrophages are derived from peripheral blood monocytes recruited into the tumor. Upon activation by MM plasma cells and mesenchymal stromal cells, macrophages can release growth factors, proteolytic enzymes, cytokines, and inflammatory mediators that promote plasma cell growth and survival. Macrophages promote tumor progression through several mechanisms including angiogenesis, growth, and drug resistance. Indeed, these macrophages are essential for the induction of an angiogenic response through vasculogenic mimicry, and this ability proceeds in step with progression of the plasma cell tu...

In tumor growth, angiogenesis, the process of new-formation of blood vessels from pre-existing ones, is uncontrolled and unlimited in time. The vascular phase is characterized by the new-formation of vascular channels that enhances tumor cell proliferation, local invasion and hematogenous metastasis. Human malignant melanoma is a highly metastatic tumor with poor prognosis, and high resistance to treatment. Parallel with progression, melanoma acquires a rich vascular network, whereas an increasing number of tumor cells express the laminin receptor, which enables their adhesion to the vascular wall, favouring tumor cell extravasation and metastases. Melanoma neovascularization has been correlated with poor prognosis, overall survival, ulceration and increased rate of relapse. Secretion of various angiogenic cytokines, i.e. VEGF-A, FGF-2, PGF-1 and -2, IL-8, and TGF-1 by melanoma cells promote the angiogenic switch and has been correlated to transition from the radial to the vertical ...

Matrix metalloproteinase (MMP) expression and production are associated with advanced-stage tumor and contribute to tumor progression, invasion and metastases. The current study was designed to determine the expression and production of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) by human lymphoid tumor cells. Changes in expression and production were also investigated during tumor progression of multiple myeloma and mycosis fungoides.In situhybridization analysis revealed that lymphoblastic leukemia B cells (SB cell line), multiple myeloma (MM) cells (U266 cell line) and lymphoblastic leukemia T cells (CEM and Jurkat cell lines) express constitutively the mRNA for MMP-2 and/or MMP-9. We demonstrated by gelatin-zymography of cell culture medium that both enzymes were secreted in their cleaved (activated) form.In situhybridization of bone marrow plasma cells and gelatin- zymography of the medium showed that patients with active MM (diagnosis, relapse, leukemic progression) express ...

In tumors, vascular endothelial growth factor-A (VEGF-A) stimulates angiogenesis and vascular permeability by activating the tyrosine kinase receptor-2 (VEGFR-2 or KDR/Flk-1) and-1 (VEGFR-1 or Flt-1). The distribution and function of VEGF homologs and their receptors on bone marrow plasma cells, endothelial cells, and other stromal cells (residual stromal cells) were examined in patients with multiple myeloma (MM). Plasma cells secrete VEGF-A (and VEGF-B, VEGF-C and VEGF-D, albeit marginally) into their conditioned medium (CM). CM VEGF-A stimulates proliferation and chemotaxis in endothelial cells (both being mandatory for angiogenesis) via VEGF receptor-2 (VEGFR-2), and in residual stromal cells via the VEGFR-1. Residual stromal cells secrete VEGF-C and VEGF-D, but little of the other homologs. Their CM VEGF-C and VEGF-D increase in response to plasma cell CM and trigger plasma cell proliferation via VEGFR-3. Proliferation in all cell types parallels VEGFR and extracellular signal-...

In multiple myeloma (MM), the mechanisms used by plasma cells to invade locally and metastasize are thought to be similar to those developed by solid tumors and include cell proliferation and secretion of extracellular matrix (ECM) degrading enzymes following adhesion to ECM proteins. We studied these mechanisms in fresh bone marrow plasma cells of patients with MM after adhesion to the ECM proteins vitronectin (VN) and fibronectin (FN). The ability of bone marrow plasma cells to adhere to VN and FN and the consequent formation of focal adhesion plaques on the cell surface, their composition and phosphorylation of several signal transduction proteins, cell proliferation and secretion of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) and urokinase-type plasminogen activator (uPA) were studied. Plasma cells adhered to immobilized VN and FN. Adhesion was fully prevented by neutralizing anti-avb3 integrin antibody. Integrin engagement caused aggregation of the plaques, which containe...

Immunohistochemical, cytochemical and ultrastructural data showing vivid angiogenesis and numerous mast cells (MCs) in the bone marrow of 24 patients with active multiple myeloma (MM) compared with 34 patients with non-active MM and 22 patients with monoclonal gammopathy of undetermined significance (MGUS) led us to hypothesize that angiogenesis parallels progression of MM, and that MCs participate in its induction via angiogenic factors in their secretory granules.

To assess whether the progression of plasma cell tumors is accompanied by angiogenesis and secretion of matrix-degrading enzymes, bone marrow biopsy specimens from 20 patients with monoclonal gammopathy of undetermined significance (MGUS), 18 patients with nonactive multiple myeloma (MM), and 26 patients with active MM were evaluated for their angiogenic potential and matrix-metalloproteinase (MMP) production. A fivefold increase of the factor VIII+ microvessel area was measured by a planimetric method of point counting in the bone marrow of patients with active MM as compared with nonactive MM and MGUS patients (P <.01). When serum-free conditioned media (CM) of plasma cells isolated from the bone marrow of each patient were tested in vivo for their angiogenic activity in the chick embryo chorioallantoic membrane (CAM) assay, the incidence of angiogenic samples was significantly higher (P <. 01) in the active MM group (76%) compared with nonactive MM (33%) and MGUS (20%) grou...

It was believed that vasculogenesis occurred only during embryo life and that postnatal formation of vessels arose from angiogenesis. Recent findings demonstrate the existence of Endothelial Precursor Cells (EPCs), which take partin postnatal vasculogenesis. EPCs are recruited from the bone marrow under the stimulation of growth factors and cytokines and reach the sites of neovascularization in both physiological and pathological conditions such as malignancies where they contribute to the “angiogenic switch” and tumor progression. An implementation of circulating EPCs in the bloodstream of patients with haematological malignancies has been demonstrated. This increase is strictly related to the bone marrow microvessel density and correlated with a poor prognosis. The EPCs characterization is a very complex process and still under investigation. This literature review aims to provide an overview of the functional and biological role of EPCs in haematological malignancies and to inves...

Increasing evidences suggest several biological roles for erythropoietin and its receptor (Epo and EpoR), unrelated to erythropoiesis, including angiogenesis. Here, we detected the expression of EpoR in bone marrow-derived endothelial cells from monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) patients (MGECs and MMECs, respectively) and assessed whether Epo plays a role in MGECs- and MMECs-mediated angiogenesis. We show that EpoR is expressed by both MGECs and MMECs even though at a higher level in the first ones. Both EC types respond to rHuEpo in terms of cell proliferation, whereas other responses, including activation of JAK2/STAT5 and PI3K/Akt pathways, cell migration and capillarogenesis are enhanced by Epo in MGECs, but not in MMECs. In addition, the conditioned media of both Epo-treated cells induce a strong angiogenic response in vivo in the chorioallantoic membrane assay, comparable to that of vascular endothelial growth factor (VEGF). O...

Multiple myeloma is a plasma cell tumor that homes to and expands in the bone marrow and that, despite the new available drugs, remains incurable. Extramedullary plasmacytoma is a not frequent manifestation during the natural history of multiple myeloma and is frequently associated with plasma cell bone marrow infiltration. The most common locations for an EMP include the gastrointestinal tract, pleura, testis, skin, peritoneum, liver, endocrine glands, and lymph nodes. Primary involvement of the gallbladder fossa is exceedingly rare. In this report, we describe a patient with multiple myeloma who achieved a clinical and serological remission after autologous transplant but progressed rapidly at extramedullary site mimicking a second cancer (i.e., pancreatic or biliary cancer). In this case, the extramedullary localization was refractory to standard therapy, differently from bone marrow localization, but responded to lymphoma-like therapy. In this patient (i) the particular site of ...

Maintenance demonstrated to improve survival in newly diagnosed multiple myeloma (NDMM) patients and the achievement of complete response (CR) is a strong predictor of survival. Nevertheless, the role of maintenance according to response after induction/consolidation has not been investigated so far. To evaluate the impact of maintenance according to response, we pooled together and retrospectively analyzed data from 955 NDMM patients enrolled in two trials (GIMEMA-MM-03-05 and RV-MM-PI-209). Primary endpoints were progression-free survival (PFS)1, PFS2 and overall survival (OS) of CR patients randomized to maintenance and no maintenance. Secondary endpoints were PFS1, PFS2 and OS in very good partial response/partial response (VGPR/PR) patients. Overall, 213 patients obtained CR after induction/consolidation, 118 received maintenance and 95 no maintenance. In patients achieving CR, maintenance significantly improved PFS1 (HR 0.50, P < 0.001), PFS2 (HR 0.58, P 0.02) and OS (HR 0....

Multiple myeloma is a B-cell lineage cancer in which neoplastic plasma cells expand in the bone marrow and pathophysiological interactions with components of microenvironment influence many biological aspects of the malignant phenotype, including apoptosis, survival, proliferation, and invasion. Despite the therapeutic progress achieved in the last two decades with the introduction of a more effective and safe new class of drugs (i.e., immunomodulators, proteasome inhibitors, monoclonal antibodies), there is improvement in patient survival, and multiple myeloma (MM) remains a non-curable disease. The bone marrow microenvironment is a complex structure composed of cells, extracellular matrix (ECM) proteins, and cytokines, in which tumor plasma cells home and expand. The role of the bone marrow (BM) microenvironment is fundamental during MM disease progression because modification induced by tumor plasma cells is crucial for composing a “permissive” environment that supports MM plasma...