Expression of tenascin is related to histologic malignancy and angiogenesis in b-cell non-Hodgkin's lymphomas

Autoantibodies specific for C1q, C3b, β2-glycoprotein 1 and annexins may amplify complement activity and reduce apoptosis-mediated immune suppression

Neoplastic cells hijack cell death pathways to evade the immune response. Phosphatidylserine, a marker of apoptotic cells, and its highly conserved bridging proteins, annexins and β2-glycoprotein I, facilitate the efficient removal of apoptotic and necrotic cells via tumor-associated phagocytes in a process called efferocytosis. Efferocytosis results in the clearance of dead and dying cells and local immune suppression. Neoplastic cells also have an increased capacity to activate complement. Complement may facilitate the silent removal of tumor cells and has a dual role in promoting and inhibiting tumor growth. Here I hypothesize that immune response-generating IgG autoantibodies that recognize opsonizing fragments C1q, C3b, and phosphatidylserine-binding proteins (annexins, β2-glycoprotein I) may reduce tumor growth. I propose that these autoantibodies induce a pro-inflammatory, cytotoxic tumor microenvironment. Further, I predict that autoantibodies can drive neoplastic cell phagocytosis in an Fc receptor-dependent manner and recruit additional complement, resulting in immune-stimulatory effects. Excessive complement activation and antibody-dependent cytotoxicity may stimulate anti-tumor responses, including damage to tumor vasculature. Here I provide insights that may aid the development of more effective therapeutic modalities to control cancer. Such therapeutic approaches should kill neoplastic cells and target their interaction with host immune cells. Thereby the pro-tumorigenic effect of dead cancer cells could be limited while inducing the anti-tumor potential of tumor-associated phagocytes.

Evaluation of tenascin-C by tenatumomab in T-cell non-Hodgkin lymphomas identifies a new target for radioimmunotherapy

The clinical outcome of T-cell non-Hodgkin lymphoma (NHL) is poor and innovative treatments are needed. Tenascin-C is a large extracellular glycoprotein not expressed under physiological conditions, but overexpressed in cancer. Aim of the study was to evaluate tenascin-C expression within pathologic tissue of T-cell NHL and determine its clinical significance. We used an immunohistochemistry approach using the anti-tenascin-C monoclonal antibody Tenatumomab in 75 systemic T-cell NHL (including 72 mature and 3 precursor T-cell NHL), and 25 primary cutaneous T-cell NHL. Data were analyzed in terms of staining intensity, proportion of involved areas and histologic pattern, and results were correlated with clinical characteristics and outcome. Ninety-three percent of the cases were tenascin-C positive and 59% of systemic diseases were characterized by a predominant involvement (>50%). Stromal expression was detected in all the cases while vascular and vascular plus cytoplasmic expression was present in 49% and 23%. The constant overexpression of the tenascin-C gene was observed in two independent publicly available T-cell NHL gene expression datasets. In conclusions, tenascin-C represents an attractive target that sets the rationale to investigate the therapeutic activity of radiolabeled Tenatumomab in T-cell NHL.

Abnormalities in alternative splicing of angiogenesis-related genes and their role in HIV-related cancers

Alternative splicing of mRNA leads to an increase in proteome biodiversity by allowing the generation of multiple mRNAs, coding for multiple protein isoforms of various structural and functional properties from a single primary pre-mRNA transcript. The protein isoforms produced are tightly regulated in normal development but are mostly deregulated in various cancers. In HIV-infected individuals with AIDS, there is an increase in aberrant alternative splicing, resulting in an increase in HIV/AIDS-related cancers, such as Kaposi’s sarcoma, non-Hodgkin’s lymphoma, and cervical cancer. This aberrant splicing leads to abnormal production of protein and is caused by mutations in cis-acting elements or trans-acting factors in angiogenesis-related genes. Restoring the normal regulation of alternative splicing of angiogenic genes would alter the expression of protein isoforms and may confer normal cell physiology in patients with these cancers. This review highlights the abnormalities in alternative splicing of angiogenesis-related genes and their implication in HIV/AIDS-related cancers. This allows us to gain an insight into the pathogenesis of HIV/AIDS-related cancer and in turn elucidate the therapeutic potential of alternatively spliced genes in HIV/AIDS-related malignancies.

The role of angiogenesis in human non-Hodgkin lymphomas

The role of angiogenesis in the growth of lymphomas and survival of patients with leukemias and other hematological malignancies has become evident since 1994. Angiogenic factors, such as vascular endothelial growth factor and its receptors together with other tumor microenvironment components, including myelo-monocytic cell, mast cells, endothelial progenitor cells, and circulating endothelial cells, have been shown to be important in the progression and maintenance of lymphoproliferative disorders. In this review article, we present an overview of the literature focusing on the relationship between angiogenesis and disease progression and the recent advantages in the antiangiogenic treatment in human non-Hodgkin lymphomas.

Prognostic Significance of Microvessel Density and Vascular Endothelial Growth Factor (VEGF) Expression in non-Hodgkin's Lymphoma

Angiogenesis has a major role in the pathogenesis of malignancies. Studies involving the role of angiogenesis have been most commonly performed in solid tumors. However, studies related to hemapoietic neoplasia and angiogenesis are relatively limited. We investigated the role of angiogenesis in non-Hodgkin's lymphomas (NHLs) and its relation with clinical and histopathologic prognostic indicators. In this respect, angiogenesis markers were evaluated in 71 patients with NHL and these were compared with other prognostic indicators including age, gender, histological grade, stage, extranodal involvement and survival. Microvessel density (MVD) using Factor VIII monoclonal antibody and vascular endothelial growth factor (VEGF) using monoclonal antibody for VEGF expression were studied in paraffin-embedded tissue samples. We did not find a significant relationship between MVD and patient characteristics including age, gender, stage, histological grade, nodal status, international prognostic index (IPI), and response to treatment. MVD was found to be greater in cases with B symptoms compared to those without B symptoms (14.6 +/- 5.7 and 11.4 +/- 5.3, respectively, p = 0.002). No significant relationship was found between VEGF and age, gender, stage, histological grade, IPI, and overall survival. The complete and partial response rate to therapy was significantly higher in VEGF-negative patients than in the VEGF-positive patients (p = 0.003). In conclusion, there appears to be a role for angiogenesis and angiogenic factors in NHLs. The combination of anti-angiogenic drugs with conventional anti-neoplastic treatment will probably be used in the future. Larger series of patients are needed to determine the prognostic value of angiogenesis in NHL.

Expression of tenascin-C and its isoforms in the breast

Tenascin-C (TNC) is an extracellular matrix glycoprotein which is frequently up-regulated in a variety of pathological conditions including chronic inflammation and cancer. TNC has been implicated in the modulation of cell migration, proliferation, invasion and angiogenesis. Multiple isoforms of TNC can be generated through the alternative splicing of nine exons located in the fibronectin type III region of the molecule. The profile of isoforms expressed differs between cancers and normal breast, with the fully truncated TNC isoform being predominant in normal and benign tissues and higher molecular weight isoforms induced predominantly in cancer. The addition of extra domains within the fibronectin type III repeat domain greatly affects TNC function with multiple exon combinations available for splicing. Exons 14 and 16 are considered to be tumour-associated and have been shown to affect breast cell line invasion and growth in vitro to a greater extent than the full-length TNC isoform. This mini review will provide a summary of the literature to date regarding the expression of TNC isoforms in the breast and also discuss more recent developments in the field regarding exon AD1.

Angiogenesis in non-Hodgkin's lymphoma: Clinico-pathological correlations and prognostic significance in specific subtypes

The aim of the study was to evaluate angiogenesis in different subtypes of non-Hodgkin's lymphoma (NHL) and to correlate angiogenic scores to clinical endpoints. Pre-therapeutic lymph node biopsies from 308 patients with NHL [107 follicular B-cell lymphoma (FL), 94 diffuse large B-cell lymphoma (DLBCL), 107 peripheral T-cell lymphoma (PTCL)] were studied. Microvessels were scored according to the Chalkley and microvessel density method (MVD) methods. Vascular endothelial growth factor (VEGF) protein expression was evaluated by immunohistochemistry. Both Chalkley and MVD methods showed, that the lymphoma subtypes differed significantly in angiogenic scores (P < 0.001). Angiogenic scores in tumor area were highest in PTCL, and lowest in FL. However, a remarkable high microvessel density was found in interfollicular areas of FL. In FL, high interfollicular MVD scores predicted progressive disease and poorer overall and event-free survival (P = 0.024 and 0.013). High interfollicular Chalkley scores correlated with transformation to DLBCL (P = 0.01). VEGF expression was detected in all NHL subtype, and the strongest expression was found in PTCL. In FL, patients with diffuse VEGF expression in lymphoma cells had poorer overall survival than those with focal expression.

Immunohistochemical Expression of Tenascin in Melanocytic Tumours of Dogs

The aim of this study was to investigate tenascin-C (TN) immunolabelling and labelling for endothelium by von Willebrand Factor (vWF) in melanocytic tumours of dogs as compared with normal tissues, to evaluate the TN distribution in these types of tumours and to investigate whether a relation could be established between TN and angiogenesis in different types of tumour. Samples of normal dog skin (n=8), benign skin melanocytomas (n=10), malignant oral melanomas (n=9) and malignant toe melanomas (n=5) were studied. The percentages of TN and vWF immunolabelling per total microscopical area were analysed by morphometric methods. In normal skin, TN was found at dermo-epidermal junctions, around hair follicles, in the smooth muscles of hair follicles, and in the walls of blood vessels. TN immunolabelling (distribution and intensity) in melanocytomas was comparable with that found in normal skin. In melanomas, TN expression was considerably increased, its intensity in toe melanomas being twice that observed in oral melanomas. The degree of TN immunolabelling was not related to the histological malignancy of the melanomas. In melanomas, TN was found in the connective tissue surrounding the tumour cell nests and in narrow stromal strands inside the tumour. Regions infiltrated with lymphocytes were devoid of TN. The presence of TN around capillaries in melanocytomas and melanomas was investigated by double-immunolabelling (for TN and vWF). The intensity of vWF and TN immunolabelling was higher in melanomas than in melanocytomas, and higher in toe melanomas than in oral melanomas; however, no clear relation between TN expression and immunolabelling for vWF was found.

Tenascin and microvessel stromal changes in patients with non-Hodgkin's lymphoma are isolated to the sites of disease and vary in correlation to disease activity

This study investigated stromal changes in expression of tenascin and vasculogenesis in lymphoma. Documenting the dynamic nature of the stromal changes in lymphoma in relation to response to therapy is helpful in planning new therapies directed at these targets. Two hundred and sixty one samples from 111 patients with varying types of non-Hodgkin's lymphoma were reviewed and examined using immunohistochemistry techniques. Samples were stained for factor VIII - related antigen for microvessel density (MVD) analysis and anti-tenascin antibody for qualitative assessment of the stromal expression. Multiple samples from the same patient were taken at the same point in time to assess whether stromal changes were limited to sites of disease. Multiple samples were examined over the course of a patient's illness to assess whether the stromal changes were modulated according to disease activity. There was a significant increase in tenascin expression and MVD in the sites of disease compared with uninvolved sites (p = 0.01 and p < 0.0001, respectively). In patients who responded to therapy, there was a decrease in the expression of tenascin (p = 0.0049) and MVD (p < 0.0001), and in those with disease progression there was an increase in the tenascin expression (p = 0.0050) and MVD (p < 0.0001). Our results suggest stromal changes are isolated to the sites of disease within patients, allowing targeted therapies to be developed. Further, stromal changes correlate with disease response over the course of the patient's disease. This new finding may have implications for the timing of anti-stromally directed therapies.

Angiogenesis in malignant lymphoma

PURPOSE OF REVIEW

Angiogenesis plays an important role in the pathophysiology of both solid tumors and hematologic malignancies. Angiogenesis-associated parameters are important prognosticators, and tumor blood vessels are an emerging target for therapy. This review addresses the evidence of the role of angiogenesis in malignant lymphoma and discusses some therapeutic implications.

RECENT FINDINGS

In angiogenesis assays, lymphoma cells show angiogenic properties. Tumor vascularization is higher in lymphoma tissue than in reactive lymph nodes and increases in step with clinically more aggressive lymphoma subtypes and advanced-stage disease. High levels of vascular endothelial growth factor in blood and tissue are associated with adverse prognosis. Vascular endothelial growth factor and vascular endothelial growth factor receptors are also present in lymphoma cells. Therapy against vascular endothelial growth factor in animal models is effective and points to both the tumor cell and the host endothelium as targets. Structural microvessel abnormalities are present in some lymphoma subtypes. The role of angiogenesis might vary in lymphoma subtypes because the prognostic value of microvessel density and the expression of angiogenesis-related molecules differ between lymphoma subtypes. There are also differences in blood vessel phenotype between lymphoma subtypes. This heterogeneity may have implications for antiangiogenic therapies. Antiangiogenic therapy in human lymphoma is still in its infancy.

SUMMARY

The role of angiogenesis in malignant lymphoma is evident. Tumor vasculature is an attractive target for lymphoma therapy. Differences between lymphoma subtypes must be taken into account in the selection of the most suitable patients for trials with antiangiogenic agents.

Microarray analysis of in vitro pericyte differentiation reveals an angiogenic program of gene expression

The vasculature consists of endothelial cells (ECs) lined by pericyte/vascular smooth muscle cells (vSMCs). Pericyte/vSMCs provide support to the mature vasculature but are also essential for normal blood vessel development. To determine how pericyte-EC communication influences vascular development, we used the well-established in vitro model of TGFbeta-stimulated differentiation of 10T1/2 cells into pericyte/vSMCs. Microarray analysis was performed to identify genes that were differentially expressed by induced vs. uninduced 10T1/2 cells. We discovered that these cells show an angiogenic program of gene expression, with up-regulation of several genes previously implicated in angiogenesis, including VEGF, IL-6, VEGF-C, HB-EGF, CTGF, tenascin C, integrin alpha5, and Eph receptor A2. Up-regulation of some genes was validated by Western blots and immunocytochemistry. We also examined the functional significance of these gene expression changes. VEGF and IL-6 alone and in combination were important in 10T1/2 cell differentiation. Furthermore, we used a coculture system of 10T1/2 and human umbilical vein ECs (HUVECs), resulting in the formation of cordlike structures by the HUVECs. This cordlike structure formation was disrupted when neutralizing antibodies to VEGF or IL-6 were added to the coculture system. The results of these studies show that factors produced by pericytes may be responsible for recruiting ECs and promoting angiogenesis. Therefore, a further understanding of the genes involved in pericyte differentiation could provide a novel approach for developing anti-angiogenic therapies.

Low-dose weekly paclitaxel for recurrent or refractory aggressive non-Hodgkin lymphoma

BACKGROUND

Many patients with recurrent, intermediate or high-grade non-Hodgkin lymphoma (NHL) may not respond to or are not candidates for aggressive salvage chemotherapy. Effective, less toxic regimens are needed. Although high-dose taxanes have not been reported to be very effective for the treatment of lymphoma, different delivery rates may allow for different mechanisms of action to be manifest and result in a different toxicity profile and response rate. The current study tested this hypothesis by using low-dose, weekly paclitaxel in patients with recurrent or refractory NHL.

METHODS

Adults age > 18 years with refractory or recurrent, aggressive NHL who were not considered curable with standard high-dose therapy received paclitaxel at a dose of 80 mg/m2 weekly for 5 weeks for 2 cycles.

RESULTS

Thirty-four patients with refractory NHL and 4 patients with recurrent disease were treated. Approximately 45% of the patients had achieved a prior disease remission. The median number of prior regimens received was 3, 74% of the patients had an International Prognostic Index of > or = 3 at the time of study entry, and 29% had failed high-dose therapy with autologous hematopoietic support. Only one patient encountered severe toxicity (sepsis). Myelosuppression was reported to occur in approximately 20% of patients. A total of 10 patients (26%) achieved a complete disease response and 4 patients (11%) achieved a partial response.

CONCLUSIONS

In the current study, low-dose, weekly paclitaxel therapy was found to provide a well tolerated and less toxic approach to the treatment of refractory NHL, with encouraging responses noted in heavily pretreated patients. However, evaluation in patients with an earlier stage of disease is warranted.

Phase 1 trial study of 131I-labeled chimeric 81C6 monoclonal antibody for the treatment of patients with non-Hodgkin lymphoma

We report a phase 1 study of pharmacokinetics, dosimetry, toxicity, and response of (131)I anti-tenascin chimeric 81C6 for the treatment of lymphoma. Nine patients received a dosimetric dose of 370 MBq (10 mCi). Three patients received an administered activity of 1480 MBq (40 mCi), and 2 developed hematologic toxicity that required stem cell infusion. Six patients received an administered activity of 1110 MBq (30 mCi), and 2 developed toxicity that required stem cell infusion. The clearance of whole-body activity was monoexponential with a mean effective half-life of 110 hours (range, 90-136 hours) and a mean effective whole-body residence time of 159 hours (range, 130-196 hours). There was rapid uptake within the viscera; however, tumor uptake was slower. Activity in normal viscera decreased proportional to the whole body; however, tumor sites presented a slow clearance (T(1/2), 86-191 hours). The mean absorbed dose to whole-body was 67 cGy (range, 51-89 hours), whereas the dose to tumor sites was 963 cGy (range, 363-1517 cGy). Despite lack of a "blocking" antibody, 1 of 9 patients attained a complete remission and 1 a partial remission. These data demonstrate this radiopharmaceutical to be an encouraging agent for the treatment of lymphoma particularly if methods to protect the normal viscera are developed.

Tenascins: regulation and putative functions during pathological stress

In this review, we discuss the structure and function of the extracellular matrix protein family of tenascins with emphasis on their involvement in human pathologies. The article is divided into the following sections:

INTRODUCTION

the tenascin family of extracellular matrix proteins; Structural roles: tenascin-X deficiency and Ehlers-Danlos syndrome; Tenascins as modulators of cell adhesion, migration, and growth; Role of tenascin-C in inflammation; Regulation of tenascins by mechanical stress: implications for wound healing and regeneration; Association of tenascin-C with cancer: antibodies as diagnostic and therapeutic tools; Conclusion and perspectives.

Tenascin-C expression and distribution in cultured human chondrocytes and chondrosarcoma cells

Tenascin-C (TNC) is an oligomeric glycoprotein of the extracellular matrix with several distinct isoforms variably expressed during embryogenesis, tumorogenesis, angiogenesis and wound healing. In the normal human adult, TNC is found in large concentrations in articular cartilage, suggesting tissue-specific function. The purpose of this study was to determine the specific in vitro TNC splicing patterns of articular chondrocytes and a human chondrosarcoma cell line. Cells were cultured in a three-dimensional bead system and TNC splice variant expression and distribution were examined with the use of Western blotting techniques, semi-quantitative reverse-transcription polymerase chain reaction and immunohistochemistry. At both the transcriptional and post-translational levels, the chondrocytes were found to express significantly higher levels of the smaller 220 kDa isoform (P < 0.01), which was predominantly incorporated into the matrix. The splicing pattern of the malignant cells was characterized by a higher proportion of the larger 320 kDa isoform which was extruded into the media. In vivo studies are necessary to verify the expression of the large TNC isoform in chondrosarcoma and the production and integration of the smaller isoform in normal chondroid matrix. In addition, elucidation of the biologic functions of the two major TNC isoforms may lead to the development of novel diagnostic and therapeutic approaches to chondrosarcoma.

Extracellular matrix components in breast carcinomas

A malignant process interferes with the normal 'programme' of extracellular matrix biosynthesis and can modify extensively the structure and composition of the matrix. This effect appears to be attributable to several processes such as direct production of some selected matrix macromolecules by malignant cells or indirectly by the production of factors by malignant cells interfering with the regulation of normal matrix production. Other possibilities may also exist, such as the direct action of an environmental carcinogen on otherwise normal mesenchymal cells. The result is a more or less profound modification of tissue structure and composition with possible feedback effects on the malignant process. Some examples will be discussed such as elastin production by some tumours as well as the biosynthesis of some other selected matrix macromolecules as tenascin and osteopontin by breast tumours. Although the detailed mechanisms of these specific matrix productions is not yet completely elucidated, the rapidly increasing knowledge on the regulation of specific matrix production process and deranged matrix production might represent a new area of crosstalk between cancer research and matrix biology.

Tenascin-C aptamers are generated using tumor cells and purified protein

Tenascin-C (TN-C) is an extracellular matrix protein that is overexpressed during tissue remodeling processes, including tumor growth. To identify an aptamer for testing as a tumor-selective ligand, SELEX (systematic evolution of ligands by exponential enrichment) procedures were performed using both TN-C and TN-C-expressing U251 glioblastoma cells. The different selection techniques yielded TN-C aptamers that are related in sequence. In addition, a crossover procedure that switched from tumor cell to purified protein selections was effective in isolating two high-affinity TN-C aptamers. When targeting tumor cells in vitro, the observed propensity of naive oligonucleotide pools to evolve TN-C aptamers may be due to the abundance of this protein. In vivo, TN-C abundance may also be well suited for aptamer accumulation in the tumor milieu. A size-minimized and nuclease-stabilized aptamer, TTA1, binds to the fibrinogen-like domain of TN-C with an equilibrium dissociation constant (K(d)) of 5 x 10(-9) m. At 13 kDa, this aptamer is intermediate in size between peptides and single chain antibody fragments, both of which are superior to antibodies for tumor targeting because of their smaller size. TTA1 defines a new class of ligands that are intended for targeted delivery of radioisotopes or chemical agents to diseased tissues.

Transcriptional response to hypoxia in human tumors

BACKGROUND

The presence of hypoxic regions within solid tumors is associated with a more malignant tumor phenotype and worse prognosis. To obtain a blood supply and protect against cellular damage and death, oxygen-deprived cells in tumors alter gene expression, resulting in resistance to therapy. To investigate the mechanisms by which cancer cells adapt to hypoxia, we looked for novel hypoxia-induced genes.

METHODS

The transcriptional response to hypoxia in human glioblastoma cells was quantified with the use of serial analysis of gene expression. The time course of gene expression in response to hypoxia in a panel of various human tumor cell lines was measured by real-time polymerase chain reaction. Hypoxic regions of human carcinomas were chemically marked with pimonidazole. Immunohistochemistry and in situ hybridization were used to examine gene expression in the tumor's hypoxic regions.

RESULTS

From the 24 504 unique transcripts expressed, 10 new hypoxia-regulated genes were detected-all induced, to a greater extent than vascular endothelial growth factor, a hypoxia-induced mitogen that promotes blood vessel growth. These genes also responded to hypoxia in breast and colon cancer cells and were activated by hypoxia-inducible factor 1, a key regulator of hypoxic responses. In tumors, gene expression was limited to hypoxic regions. Induced genes included hexabrachion (an extracellular matrix glycoprotein), stanniocalcin 1 (a calcium homeostasis protein), and an angiopoietin-related gene.

CONCLUSIONS

We have identified the genes that are transcriptionally activated within hypoxic malignant cells, a crucial first step in understanding the complex interactions driving hypoxia response. Within our catalogue of hypoxia-responsive genes are novel candidates for hypoxia-driven angiogenesis.

Tenascin-C splice variant adhesive/anti-adhesive effects on chondrosarcoma cell attachment to fibronectin

Tenascin-C is an oligomeric glycoprotein of the extracellular matrix that has been found to have both adhesive and anti-adhesive properties for cells. Recent elucidation of the two major TNC splice variants (320 kDa and 220 kDa) has shed light on the possibility of varying functions of the molecule based on its splicing pattern. Tenascin-C is prominently expressed in embryogenesis and in pathologic conditions such as tumorogenesis and wound healing. Fibronectin is a prominent adhesive molecule of the extracellular matrix that is often co-localized with tenascin-C in these processes. We studied the chondrosarcoma cell line JJ012 with enzyme-linked immunoabsorbance assays, cell attachment assays and antibody-blocking assays to determine the adhesive/anti-adhesive properties of the two major tenascin-C splice variants with respect to fibronectin and their effect on chondrosarcoma cell attachment. We found that the small tenascin-C splice variant (220 kDa) binds to fibronectin, whereas the large tenascin-C splice variant (320 kDa) does not. In addition, the small tenascin-C splice variant was found to decrease adhesion for cells when bound to fibronectin, but contributed to adhesion when bound to plastic in fibronectin-coated wells. Antibody blocking experiments confirmed that both the small tenascin-C splice variant and fibronectin contribute to cell adhesion when bound to plastic. The large tenascin-C splice variant did not promote specific cell attachment. We hypothesize that the biologic activity of tenascin-C is dependent on the tissue-specific splicing pattern. The smaller tenascin-C isoform likely plays a structural and adhesive role, whereas the larger isoform, preferentially expressed in malignant tissue, likely plays a role in cell egress and metastasis.

Angiogenesis in multiple myeloma: correlation between in vitro endothelial colonies growth (CFU-En) and clinical-biological features

Mouse models and studies performed on fixed bone marrow (BM) specimens obtained from patients with multiple myeloma (MM) suggest that plasma cell growth is dependent on endothelial cell (EC) proliferation within the BM microenvironment. In order to assess whether EC overgrowth in MM reflects a spontaneous in vitro angiogenesis, BM mononucleated cells from 13 untreated (UT) MM, 20 treated (11 with melphalan and nine with DAV schedule) MM, eight patients with monoclonal gammopathy of uncertain significance (MGUS) and eight controls were seeded in an unselective medium to assess EC proliferation. Furthermore, the influence of IL6 on the EC growth was investigated. Endothelial colonies (CFU-En) appeared as small clusters, formed by at least 100 slightly elongated and sometimes bi-nucleated cells expressing factor VIII, CD31 and CD105 (endoglin). The CFU-En mean number/10(6) BM mononucleated cells in untreated MM samples (2.07 s.d. +/- 1.3) was significantly higher than in normal BM (0.28 +/- 0.48), while no difference was seen between normal BM and MGUS (0.28 +/- 0.54). Interestingly, the mean number of CFU-En in the DAV group (1.88 +/- 1.6) did not differ from the UT, while it was found to be lower in the melphalan group (0.31 +/- 0.63). The addition of anti-IL6 monoclonal antibody induced a reduction of both the plasma cells in the supernatant and the CFU-En number. This study describes a rapid and feasible assay providing support for the association between EC and plasma cells further suggesting that the in vitro angiogenesis process may parallel that observed in vivo.

Tenascin expression and angiogenesis in breast cancers

The expression and the distribution of tenascin as well as the extent of blood vessel formation (angiogenesis) were investigated in 70 invasive human breast carcinomas. Formalin-fixed, paraffin-embedded specimens were stained with monoclonal antibody against tenascin-C (DAKO and Biogenex). Anti-CD31 antibody (Biogenex), an acknowledged marker of stromal angiogenesis, was used to detect endothelial cells. Tenascin immunostaining was positive in the tumours around the persisting normal ducts, around tumour-cell nests, in the neostroma, in some tumour cells, and it was found in or around vascular channels. Tumour vascularity was assessed by quantitative vascular grading (Chalkley point count) and was related to the localization and intensity of tenascin immunoreactivity. 19 tumours (27.1%) were scored as low, 35 (50%) as medium, and 16 (22.9%) as having a high vascular grade. The positive correlation between the vascular grade and the tenascin immunopositivity in tumour stroma was observed. Our results suggest that tenascin expression may be associated with endothelial cell activation and may play an important role in tumour angiogenesis.

Tenascin expression in primary and recurrent breast carcinomas and the effect of tenascin on breast tumor cell cultures

Tenascin is generally classified as an anti-adhesive protein. Many cells do not adhere to tenascin or if they adhere they do not spread. In this study we analysed the stromal expression of tenascin-C in primary, second primary and recurrent breast carcinomas and the ability of tenascin-C to stimulate the focal adhesion plaques in MDA-MB-435 breast carcinoma cell line. To assess the tenascin-C expression formalin-fixed, paraffin-embedded specimens of 20 specially selected breast carcinomas and their recurrences (14) or a second primary breast cancer of the same patient (6) were examined with immunohistochemical methods. We also studied the effect of tenascin-C on focal adhesion plaques added to MDA-MB-435 breast carcinoma cell line. During a median 2,9-year patient follow up 14 local recurrences and 6-second primary breast carcinomas developed in the 20 patients. In 3 cases a second recurrence occurred. The presence of tenascin in tumor cells, in the proliferating and some normal ducts, near to the tumor cell nests, in the stroma and in ductal carcinoma in situ component of the invasive carcinoma may suggest the role of tenascin played in tumor cell migration. Soluble tenascin added to the cell culture had minimal or no effect on focal adhesion plaques. Tenascin only seems not to be of prognostic value in predicting the local recurrence of breast cancer.

Angiogenesis extent and macrophage density increase simultaneously with pathological progression in B-cell non-Hodgkin's lymphomas

Node biopsies of 30 benign lymphadenopathies and 71 B-cell non-Hodgkin's lymphomas (B-NHLs) were investigated for microvessel and macrophage counts using immunohistochemistry and morphometric analysis. Both counts were significantly higher in B-NHL. Moreover, when these were grouped into low-grade and high-grade lymphomas, according to the Kiel classification and Working Formulation (WF), statistically significant higher counts were found in the high-grade tumours. Immunohistochemistry and electron microscopy revealed a close spatial association between microvessels and macrophages. Overall, the results suggest that, in analogy to what has already been shown in solid tumours, angiogenesis occurring in B-NHLs increases with tumour progression, and that macrophages promote the induction of angiogenesis via the release of their angiogenic factors.

Characteristic proliferations of reticular and dendritic cells in angioimmunoblastic lymphoma

Angioimmunoblastic lymphoma (AIL) is a T-cell proliferation with a distinct clinical presentation that often poses a difficult diagnostic challenge. Angioimmunoblastic lymphoma is characterized by prominent vascular and stromal proliferations. Using a panel of antibodies, we investigated the nature of the stromal component in 15 cases of AIL as compared with 40 cases of nodal-based peripheral T-cell lymphoma (PTCL) of other types. As has been previously noted, extrafollicular proliferations of follicular dendritic cells (detected by CD21 and low molecular-weight nerve growth factor receptor staining) were highly associated with AIL and were only rarely seen in other lesions. Unexpectedly, large networks of desmin-positive reticulum cells also were noted in all cases of AIL evaluated. These cells with characteristic long cytoplasmic processes were present in much smaller numbers or only rarely in other types of peripheral T-cell lymphoma. This population of nodal stromal cells, a subset of the fibroblastic reticulum cells detected by vimentin immunostaining, may be responsible for the prominent reticulum deposition seen in AIL. No association of AIL with proliferations of other types of reticulum cells (e.g., interdigitating dendritic cells or histiocytes) was noted. These findings suggest that networks of follicular dendritic and desmin-positive reticulum cells are useful diagnostic features in angioimmunoblastic lymphoma and probably are related to the pathogenesis of this entity.

Do mast cells help to induce angiogenesis in B-cell non-Hodgkin's lymphomas?

Morphological and morphometric data showing a higher number of mast cells (MCs) in the stroma of B-cell non-Hodgkin's lymphomas (B-NHL) than in benign lymphadenopathies are presented in support of the suggestion that angiogenesis during the progression of B-NHL may be partly mediated by angiogenic factors in their secretory granules.

Expression of tenascin is related to angiogenesis in pre-eclampsia

METHODS

Ten samples of decidua basalis from pre-eclamptic women and 10 from healthy primigravid women subjected to caesarean section (control tissues) were investigated immunohistochemically for changes in angiogenesis and expression of tenascin, an extracellular matrix protein thought to modulate angiogenesis. In addition, pre-eclamptic and control samples were grafted onto the chick embryo chorioallantoic membrane (CAM) to study their possible angiogenic activity in vivo.

RESULTS

Although the microvessel area was low in control samples, it increased significantly in the pre-eclamptic decidua. In parallel, the area covered by tenascin staining underwent a significant expansion that was highly correlated with the microvessel area. Angiogenic activity was assessed both macroscopically and microscopically on histological sections 4 days after grafting. In contrast to control samples, pre-eclamptic decidua induced an intense capillary growth, and numerous capillaries converging towards the implant and forming a spoke-wheel pattern were evident. Histological examination using a planimetric point-count method showed that microvessel counts in the CAM area under and around the pre-eclamptic implants were significantly higher than those of control samples. Again, the extracellular matrix of nearby microvessels was strongly immunoreactive with tenascin.

CONCLUSION

It is suggested that, unlike normal decidua, pre-eclamptic decidua displays an intense, autonomous angiogenic activity, probably mediated by tenascin in addition to its own angiogenic factors.