Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the hematopoietic compartment, the CD13/APN metalloprotease is one of the earliest markers of cells committed to the myeloid lineage where it is expressed exclusively on the surface of myeloid progenitors and their differentiated progeny. CD13/APN is also found in nonhematopoietic tissues, and its novel expression on the endothelial cells of angiogenic, but not normal, vasculature was recently described. Treatment of animals with CD13/APN inhibitors significantly impaired retinal neovascularization, chorioallantoic membrane angiogenesis, and xenograft tumor growth, indicating that CD13/APN plays an important functional role in vasculogenesis and identifying it as a critical regulator of angiogenesis. To investigate the mechanisms of CD13/APN induction in tumor vasculature, the regulation of CD13/APN by factors contributing to angiogenic progression was studied. In this report, it is shown that endogenous CD13/APN levels in primary cells and cell lines are up-regulated in response to hypoxia, angiogenic growth factors, and signals regulating capillary tube formation during angiogenesis. Transcription of reporter plasmids containing CD13/APN proximal promoter sequences is significantly increased in response to the same angiogenic signals that regulate the expression of the endogenous gene and in human tumor xenografts, indicating that this fragment contains elements essential for the angiogenic induction of CD13/APN expression. Finally, functional antagonists of CD13/APN interfere with tube formation but not proliferation of primary vascular endothelial cells, suggesting that CD13/APN functions in the control of endothelial cell morphogenesis. These studies clearly establish the CD13/APN metalloprotease as an important regulator of endothelial morphogenesis during angiogenesis.
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PMID:CD13/APN is activated by angiogenic signals and is essential for capillary tube formation. 1115 81

Despite the abundance of reports describing adult cases of t(8;21) acute myelocytic leukemia (AML), childhood cases have received little attention. We retrospectively investigated 14 childhood cases of t(8;21) AML, and compared their clinical characteristics with those of adult cases, focusing on the risk factors for poor prognosis. Seventy-one percent of the patients had fever. Their mean leukocyte count was 12,700/microliter, and they showed decreased NAP activity. The cell surface showed positivity for CD13, 33, 19, 34, and HLA-DR. The complete remission rate was 100%, and relapse was observed in three of the patients. Bone marrow eosinophilia was present in a smaller proportion of the childhood cases than in the adult cases. Although an increased leukocyte count, tumor formation, and other risk factors have been reported in adults, there was no correlation between these factors and prognosis in our childhood cases. As children who showed AML relapse had TdT-positive blasts, detectable blast TdT activity may be a risk factor for relapse in childhood cases of t(8;21) AML. However, to confirm this, a study with a larger subject base should be conducted.
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PMID:[Childhood t(8;21) acute myelocytic leukemia: a comparison of clinical features and risk factors with adult cases]. 1123 36

At the ISAC 2000 Congress, the Clinical Cytometry Society organized a meeting of international experts to reach consensus on the minimum number of antibodies required for a full evaluation of hematologic and lymphoid neoplasias. A questionnaire was distributed prior to the meeting to numerous experts from US and European institutions and 13 responses were received. At the meeting, 25 individuals, including most of those who returned responses, participated in the discussions and voted on the issues presented. In chronic lymphoproliferative disorders (CLD), 9 antibodies (anti-CD5, CD19, kappa, lambda, CD3, CD20, CD23, CD10, and CD45) were deemed essential for initial evaluation by 75% of the participants. There was near unanimity that additional markers (selected from CD22, FMC7, CD11c, CD103, CD38, CD25, CD79b and heavy chains for B-cell disorders, and CD4, CD7, CD8, CD2, CD56, CD16, TCRa/b, and TCRg/d for T-cell disorders) would be needed to fully characterize CLD, although not every marker would be useful in all cases. Tissue lymphomas were believed to be similar to CLD, needing a minimum of 12--16 markers. However, for some cases, CD30, bcl-2, TdT, CD71, CD1a, and CD34 were cited as useful by the participants. Markers mentioned for plasma cell disorders included kappa, lambda, CD38, CD45, CD56, CD19, CD20, CD138, and heavy chains. Of 17 voting participants, 16 agreed that between 5 to 8 markers would be essential reagents for plasma cell disorders. For acute leukemia (AL), 10 markers (CD10, CD19, CD13, CD33, CD34, CD45, CD7, CD14, CD3, and HLADR) were considered essential by 75% of participants for initial characterization of the leukemia lineage. Most (>75%) agreed that at least one more B (CD20, CD22, CD79a, IgM), T (CD1a, CD2, CD4, CD5, CD8), myeloid (CD11b, CD15, CD64, CD117, myeloperoxidase), erythroid (CD36, CD71, glycophorin A), and megakaryocytic (CD41, CD61) reagents should be included in the essential panel. However, there was no agreement as to which was optimal. Thus, approximately 13--15 of those reagents would be considered essential in all cases of AL, whereas others (CD16, CD56, CDw65, TdT, and cytoplasmic CD3) were mentioned as useful in some cases. Almost all voting participants believed that the appropriate number of markers for complete characterization of AL would average 20--24. The majority of the responders (11 of 13) indicated that fewer reagents could be used in monitoring or staging patients with previously characterized disease, but not all ventured a specific number of reagents. From the above results, we conclude that the phenotypic analysis of hematologic and lymphoid neoplasia requires a rather extensive panel of reagents. Supplementary reagents might even be necessary if they prove to become relevant for diagnostic purposes. Reducing the number of antibodies could significantly compromise the diagnostic accuracy, appropriate monitoring, or therapy of these disorders.
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PMID:Optimal number of reagents required to evaluate hematolymphoid neoplasias: results of an international consensus meeting. 1124 3

This work aims to demonstrate that CD4(+)CD56(+) malignancies arise from transformed cells of the lymphoid-related plasmacytoid dendritic cell (pDC) subset. The analysis of malignant cells from 7 patients shows that in all cases, like pDCs, leukemic cells are negative for lineage markers CD3, CD19, CD13, CD33, and CD11c but express high levels of interleukin-3 receptor alpha chain (IL-3Ralpha), HLA-DR, and CD45RA. Tumor cells produce interferon-alpha in response to influenza virus, while upon maturation with IL-3 they become a powerful inducer of naive CD4(+) T-cell proliferation and promote their T-helper 2 polarization. As pDCs, leukemic cells also express pre-Talpha and lambda-like 14.1 transcripts, arguing in favor of a lymphoid origin. In addition, malignant cells express significant levels of CD56 and granzyme B. Overall, those observations suggest that CD4(+)CD56(+) leukemic cells could represent the malignant counterpart of pDCs, both of which are closely related to B, T, and NK cells.
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PMID:Identification of a leukemic counterpart of the plasmacytoid dendritic cells. 1134 51

The human parvovirus adeno-associated virus type 2 (AAV-2) possesses many features that make it an attractive vector for gene delivery in vivo. However, its broad host range may limit its usefulness and effectivity in several gene therapy applications in which transgene expression needs to be limited to a specific organ or cell type. In this study, we explored the possibility of directing recombinant AAV-2 transduction by incorporating targeting peptides previously isolated by in vivo phage display. Two putative loops within the AAV-2 capsid were examined as sites for incorporation of peptides. We tested the effects of deleting these loops and different strategies for the incorporation of several targeting peptides. The tumor-targeting sequence NGRAHA and a Myc epitope control were incorporated either as insertions or as replacements of the original capsid sequence. Viruses were assessed for packaging, accessibility of incorporated peptides, heparin binding, and transduction in a range of cell lines. Whereas recombinant viruses containing mutant capsid proteins were produced efficiently, transduction of several cell lines was significantly impaired for most modifications. However, certain mutants containing the peptide motif NGR, which binds CD13 (a receptor expressed in angiogenic vasculature and in many tumor cell lines), displayed an altered tropism toward cells expressing this receptor. Based on this work and previous studies, possible strategies for achieving in vivo targeting of recombinant AAV-2 are discussed.
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PMID:Incorporation of tumor-targeting peptides into recombinant adeno-associated virus capsids. 1140 11

BACKGROUND: CD56 which is considered as a marker of natural killer cells is also expressed in some cases of acute myelogenous leukemia (AML) and is involved in cell adhesion mediating extramedullary leukemic infiltration. CD7/CD56 coexpression has been suggested to be a distinct biological and clinical entity of AML. PATIENT: This is a report of a 53-year-old woman who developed CD7/CD56-positive AML with primary manifestation as intracranial tumor. The patient reported of neurological impairment (impairment of visus and occurrence of double pictures). Cranial computed tomography showed an intracranial tumor, and histological examination exhibited myeloid blast cells. Peripheral leukocyte count at admission was within the normal range (5,32 Gpt/l), and percentage frequency of blasts in the blood smears was 54%. Cytological bone marrow examination showed diffuse infiltration by the same myeloid blast cells. The immunophenotype was CD7/CD13/CD33/CD38/CD56/ HLA-DR-positive. The blast cells were myeloperoxidase-positive but lactoferrin-negative. Thus, diagnosis of acute myeloid leukemia (M2 FAB) was established. Treatment consists of chemotherapy (Ara-C and anthracycline) and local radiation of the intracranial tumor. After treatment patient achieved a complete remission. CONCLUSION: With regard to the literature CD7/CD56-positive AML have a high incidence of central nervous system involvement which should be kept in mind and may be associated to CD56 expression. Copyright 2000 S. Karger GmbH, Freiburg
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PMID:Primary Intracranial Manifestation of CD7/CD56-Positive Acute Myelogenous Leukemia. 1144 Dec 65

This report describes an unusual extramedullary hematologic malignancy in an 18-month-old child who presented with a capillary leak syndrome that evolved into hyperleukocytosis with malignant cells. The circulating tumor cells did not express an antigen profile typical of any subtype of leukemia commonly observed in children. Tumor cells were CD3(-)/CD56(+); had germline TCR genes; and strongly expressed CD30, epithelial membrane antigen, and anaplastic lymphoma kinase (ALK) consistent with a null cell anaplastic large cell lymphoma (ALCL). The malignant cells contained a t(2;19)(p23;p13.1) that interrupted ALK and translocated it to the der(19). Reverse transcriptase-polymerase chain reaction and nucleotide sequence analysis revealed fusion of ALK to tropomyosin 4, an ALK fusion partner not described previously in hematologic malignancies. The clinical presentation and phenotypic features of this malignancy were not typical for ALCL because tumor cells expressed both myeloid (CD13, CD33, HLA-DR) and natural killer (NK) cell antigens. The neoplastic cells most resembled NK cells because in addition to being CD3(-)/CD56(+) with germline TCR genes, these cells were CD25(+)/CD122(+)/granzyme B(+) and possessed the functional properties of immature NK cells. The unusual clinical presentation, immunophenotype, and functional properties of these neoplastic cells suggest that this malignancy may be derived from the putative myeloid-NK precursor cell. Furthermore co-expression of NK and ALCL features supports the concept that a minority of null-ALCL may be derived from NK cells and expands the spectrum of phenotypes that can be seen in tumors produced by ALK fusion proteins. (Blood. 2001;98:1209-1216)
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PMID:Unusual childhood extramedullary hematologic malignancy with natural killer cell properties that contains tropomyosin 4--anaplastic lymphoma kinase gene fusion. 1149 72

A 41-year-old man visited his doctor in May 2000 because of a sore throat and high fever. His symptoms did not improve, despite administration of antibiotics and nonsteroidal anti-inflammatory drugs. Since a chest X-ray examination revealed an anterior mediastinal bulky tumor, he was referred and admitted to our hospital on June 21, 2000. The peripheral white blood cell count was 44,540/microliter with 74% myeloblasts. Bone marrow aspiration revealed a hypercellular marrow with 82% myeloblasts, which were negative for peroxidase and alpha-naphthyl butylate esterase staining. Blast cells were positive for CD7, CD13, CD33, CD34, and HLA-DR, and negative for CD56. A needle biopsy specimen of the mediastinal tumor consisted of myeloblasts. We diagnosed the patient as having CD7 (+) acute myeloid leukemia (AML) (M0) with a bulky mediastinal mass based on the surface marker analysis, although the clinical features resembled myeloid/NK precursor acute leukemia. The patient achieved a complete remission after two courses of induction therapy. We are planning an allogeneic stem cell transplantation during his first remission because of the high risk of relapse.
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PMID:[CD7(+) acute myeloid leukemia (M0) associated with a mediastinal bulky mass lesion]. 1157 5

The NGR peptide motif is an aminopeptidase N (CD13) ligand that targets angiogenic blood vessels. NGR-containing peptides have proven useful for delivering cytotoxic drugs, proapoptotic peptides, and tumor necrosis factor-alpha(TNF) to tumor vasculature. Given that CD13 is not only expressed in the angiogenic endothelium but also in other cell types, the mechanism(s) for the tumor-homing properties of NGR-drug conjugates remains elusive. We have examined the expression of CD13 in normal and neoplastic human tissues and cells by using two anti-CD13 monoclonal antibodies. The immunoreactivity patterns obtained with cultured cells and tissue sections from kidney, breast, and prostate carcinomas suggest that different CD13 forms are expressed in myeloid cells, epithelia, and tumor-associated blood vessels. Both, direct binding assays with a CNGRCG-TNF conjugate (NGR-TNF) and competitive inhibition experiments with anti-CD13 antibodies showed that a CD13 isoform expressed in tumor blood vessels could function as a vascular receptor for the NGR motif. In contrast, CD13 expressed in normal kidney and in myeloid cells failed to bind to NGR-TNF. Consistently with these results, neither murine(125)I-NGR-TNF nor (125)I-TNF accumulated in normal organs containing CD13-expressing cells after administration to mice. These findings may explain the selectivity and the tumor-homing properties of NGR-drug conjugates and may have important implications in the development of vascular-targeted therapies based on the NGR/CD13 system.
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PMID:Differential binding of drugs containing the NGR motif to CD13 isoforms in tumor vessels, epithelia, and myeloid cells. 1183 May 45

There is increasing interest in the exploitation of molecular addresses for the targeting of tumor imaging or therapeutic agents. A recent study demonstrated anticancer activity in human xenografts of doxorubicin (DOX)-peptide conjugates targeted to the tumor vascular endothelium, among them DOX coupled to the cyclic pentapeptide CNGRC [Science 279 (1998) 377]. In order to learn more about the mechanism of action of this type of DOX-peptide conjugates, we have studied the interaction of DOX-CNGRC with primary human umbilical cord vein endothelial cells (HUVEC) and tumor cells under defined in vitro conditions. We used a DOX conjugate, in which the cyclic CNGRC peptide, for which an in vivo endothelial address has recently been identified as aminopeptidase N (APN)/CD13, has been coupled via a hydrolysable spacer to the C-14 anthracycline-side chain. First we determined that the t(1/2) of DOX-CNGRC conjugate in human blood was 442 min (at 37 degrees ) allowing sufficient time for endothelial targeting when administered i.v. When cultured cells were exposed for 30 min to DOX-CNGRC a more cytoplasmic localization of fluorescent drug was seen when compared to DOX exposure and intracellular DOX-CNGRC was identified after extraction from the cells. This revealed differences in the cellular uptake process of the conjugate compared to DOX. The antiproliferative effect of DOX-CNGRC was determined by 30 min exposure in medium with a high protein content in order to mimick the in vivo targeting situation. In this medium, the IC(50) was 1.1 microM for highly CD13 expressing HT-1080, 1.45 microM for CD13 negative SK-UT-1 sarcoma cells and 6.5 microM for CD13 positive HUVEC. The IC(50) of DOX for these cells were 1.0, 2.0 and 7.3 microM, respectively. Although DOX-CNGRC inhibited the peptidase activity of CD13 up to 50%, our data do not favor an important role for the enzyme inhibition in the cytotoxic effect of the conjugate. The antitumor activity was tested in nude mice bearing human ovarian cancer xenografts (OVCAR-3). A weekly i.v. administration (3mg/kg DOX-equivalent, 3x) showed a minor (40%) growth delay, which does not indicate efficacy better than that expected for free DOX. In conclusion, this study indicates that the antiproliferative and anti-angiogenic effects of DOX-CNGRC as reported before, are likely caused by the cytostatic effects of intracellularly released parent drug DOX, independent of CD13 expression/activity. More research is needed to identify the optimal specific chemical configuration of DOX-peptide conjugates for in vivo targeting and receptor-mediated cellular uptake.
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PMID:A doxorubicin-CNGRC-peptide conjugate with prodrug properties. 1191 42


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