Identification of APN/CD13 as the target antigen of FU3, a human monoclonal antibody that recognizes malignant fibrous histiocytoma
ABSTRACT Malignant fibrous histiocytoma (MFH), a high-grade, undifferentiated sarcoma, is highly aggressive, resistant to radiochemotherapy and associated with poor prognosis. There are no specific immunohistochemical markers for its diagnosis. The MFH cell line SFT7913 served as and immunogen for the generation of the FU3 monoclonal antibody in our laboratory. FU3 reacted strongly with MFH cells and with perivascular mesenchymal cells. In this study, we demonstrated that the antigen recognized by FU3 was identical to aminopeptidase N (APN/CD13) using FU3 immunoaffinity chromatography and N-terminal amino acid sequencing. Frequent (80%) and high-grade (>50% of cells) expression of APN/CD13 was observed in MFH, although low-grade expression was seen in some other sarcomas. Moreover, small interfering RNA (siRNA) that specifically targets APN/CD13 significantly suppressed MFH cell invasion in vitro. The newly developed monoclonal antibody FU3 specifically recognizes CD13 on MFH cells. Decreased expression of CD13, mediated by siRNA-mediated knockdown, attenuated the invasive capacity of MFH cells. Thus, results indicate that APN/CD13 could be an important diagnostic biomarker and therapeutic target for MFH.
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ABSTRACT: We have evaluated epidemiology, prognosis and the association between metastases and local recurrence in a series of adult patients with soft tissue sarcoma (STS) of the extremity and trunk wall. 508 patients were diagnosed in the Southern Swedish Health Care Region from 1964 through 1989. The series was population-based, i.e., all patients within a defined area were included, irrespective of where treated, thereby avoiding selection bias in referral and follow-up. Epidemiology. The annual incidence was 18 per million. The median age was 64 years. One third of the tumors were subcutaneous, and these were smaller than the deep-seated tumors. Malignant fibrous histiocytoma and grade IV were the commonest. Differences were noted in clinicopathologic features among histotypes. The 5-year metastasis-free survival rate (MFSR) was 0.6. The crude local recurrence rate was 0.3. The majority of metastases and local recurrences occurred within 3 years. The referral pattern to the tumor center has become more favorable over time; in the last 5 years half of the subcutaneous and four fifths of the deep-seated tumors were referred before surgery. Prognostic factors. Tumor size, tumor necrosis, and vascular invasion were strong and independent prognostic factors for metastasis in a histologically mixed series. In MFH, storiform and pleomorphic subtype, tumor necrosis and tumor size were associated with a poor prognosis. Tumor necrosis and vascular invasion independently worsened the prognosis in leiomyosarcoma. In liposarcoma, tumor necrosis and in synovial sarcoma, tumor size were the only important prognostic factors. Tumor size, tumor necrosis, and vascular invasion were used in a prognostic system which identified two thirds of all patients with a 5-year MFSR of 0.8 and one third of the patients with a 5-year MFSR of 0.3. Metastasis and local recurrence. The causal association proposed for local recurrence and metastasis should be interpreted with caution. We suggest that highly malignant tumors combine local and distant aggressiveness, and that local recurrence is a marker of risk, and not necessarily a cause of, metastasis. Conclusions. 1. Population-based series are preferable when studying epidemiology in soft tissue sarcoma. 2. We propose that tumor size, tumor necrosis, and vascular invasion are strong and reliable factors that can be used to improve prognostic accuracy. 3. There is a growing body of evidence against a causal relationship between local recurrence and metastasis.Acta orthopaedica Scandinavica. Supplementum 07/1994; 259:1-31.
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ABSTRACT: Tumor cells from several sources produce a factor(s) which stimulates fibroblast collagenase production. Monoclonal antibodies have been raised against the tumor cell collagenase-stimulatory factor from LX-1 human lung carcinoma cells and have been used for purification of the factor from LX-1 cell membranes. These purified preparations stimulated fibroblast collagenase production, and 80% of these preparations contained a single Mr approximately 58,000 protein detectable by immunoblotting; the other 20% contained an additional minor component with a molecular weight of 35,000. A single protein with a molecular weight of approximately 58,000 was also detected in radiolabeled preparations of the purified factor by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. Conditioned media from LX-1 cells contain several species with molecular weights lower than 58,000 which are immunologically cross-reactive with the membrane-derived factor. Immunofluorescence analysis indicates that the tumor cell collagenase-stimulatory factor is distributed on the outer surface of LX-1 cells and is absent from the cell surface of fibroblasts. These and previous results indicate that the factor is present on the tumor cell surface, is released into conditioned media possibly after proteolytic cleavage, and appears to have an important role in inducing collagenolysis of host stroma during tumor invasion.Cancer Research 07/1989; 49(12):3385-91. · 9.28 Impact Factor
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ABSTRACT: We have established four cell lines from a human malignant fibrous histiocytoma. Each cell line had human aneuploid karyotype and DNA aneuploidy. Cells in all lines expressed CD13, CD68 and vimentin but lacked CD11, CD14, CD15, CD16, CD45, HLA class II and other mesenchymal and epithelial markers such as desmin, alpha-smooth muscle, myoglobin, S-100 protein, and cytokeratin. None of the cells expressed surface IgG or C3 receptor, nor did any of them phagocytose latex particles. The cells reacted with an antibody for prolyl-4-hydroxylase, but no collagen (types I, II, III, or IV) was detected in any of the cell lines. The homogenates of all cell lines had cyclic nucleotide phosphodiesterase 3 activity. Two cell lines produced granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-1alpha, IL-6 and tumor necrosis factor alpha, another line produced G-CSF, IL-1alpha, IL-6 and platelet-derived growth factor (PDGF)-AB, and the remaining cell line produced only PDGF-AB. None of the cells produced transforming growth factor-alpha. The results indicated that the cell lines were immunophenotypically similar to primitive mesenchymal cells.Oral Oncology 10/2001; 37(6):527-36. DOI:10.1016/S1368-8375(01)00004-5 · 3.03 Impact Factor