Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transferrin receptor expression is essential for the proliferation of both normal and malignant T cells. While transferrin receptor expression in normal T cells is tightly coupled to interleukin-2 receptor expression, transferrin receptor expression in malignant cells is usually constitutive and is released from this constraint. Temporally, the appearance of these membrane receptors is preceded by changes in the expression of the proto-oncogenes c-myc and c-myb. In addition, although an increase in the level of intracellular free calcium occurs early in the sequence of T-cell activation, the activation events dependent on this calcium flux have not been resolved. In the present study we report that diltiazem, an ion channel-blocking agent that inhibits calcium influx, arrested the growth in vitro of both normal and malignant human T cells in the G1 phase of the cell cycle. However, diltiazem did not inhibit the expression of c-myc or interleukin-2 receptor mRNA and protein in normal mitogen-activated T cells or the constitutive expression of c-myc and c-myb mRNA in malignant T cells (T acute lymphoblastic leukemia cells). In contrast, diltiazem prevented the induction of transferrin receptor (mRNA and protein) in normal T cells and caused a progressive loss of transferrin receptor (mRNA and protein) in malignant T cells. These data demonstrate that diltiazem can dissociate several growth-related processes normally occurring in G1 and thereby disrupt the biochemical cascade leading to cell proliferation.
Mol Cell Biol 1986 Dec
PMID:Diltiazem inhibits transferrin receptor expression and causes G1 arrest in normal and neoplastic T cells. 243 98

The membrane molecule termed "7F7-antigen" has been found to be involved in several examples of cell-cell interactions. This 85 kDa glycoprotein with a protein core of about 55 kDa contains N-linked and O-linked carbohydrates. It has an isoelectric point of 8.0-8.5 and is expressed on 20% of peripheral blood mononuclear cells, 35% of peripheral blood B-cells, follicular dendritic cells and vascular endothelium. It is also expressed on activated T-cells and its expression on B-cells, fibroblasts and monocytes increases after treatment with PWM, interferon-gamma and after three days culture, respectively. The MAb 7F7 used to define this antigen inhibits the initiation of T-cell proliferation induced by anti-CD3, PHA, ConA and (weakly) allogenic stimulator cells, but does not affect the growth of IL-2 dependent T-cells and does not interfere with the killing of PHA-blasts by allogenic IL-2 dependent T-cells. 7F7 also inhibits the binding of C3-coated sheep erythrocytes to B-cells, the PMA-induced aggregation of U937 and the binding of activated T-cells to fibroblasts. The 7F7-antigen is expressed on some non-Hodgkin lymphomas of B-cell differentiation, particularly those with follicular structure, but not on Burkitt's lymphoma, ALL or carcinomas of various tissues. It is, however, found on fibrous tissue surrounding infiltrating carcinoma cells. The expression of a melanoma antigen, P3.58, which was shown to be identical to 7F7-antigen correlates with stage and spread of invasive melanoma. It was concluded that the 7F7-antigen, which is probably related to a previously described adherence molecule (ICAM-1), is of biological importance for the initiation of T-cell responses. With the possible exception of melanoma its expression on neoplastic cells in vivo is unlikely to be of importance for the spread of malignant disease.
Mol Immunol 1988 Nov
PMID:Importance of an 85 kDa membrane glycoprotein for a variety of cell-cell interactions. 246 58

It has been reported previously that ammonium chloride, chloroquine, monensin, and adenovirus-2 potentiate the cytotoxicity of several protein toxins conjugated with various targeting molecules. We have tested whether these agents, and protein components of adenovirus-2, would enhance the cytotoxicity of conjugates of gelonin with J5, an antibody directed against common acute lymphoblastic leukemia-associated antigen, with 5E9, an antibody directed against human transferrin receptor, or with ricin B-chain. We found that none of these agents affected the cytotoxicity of gelonin conjugates to any significant extent. For example, monensin moderately (3-fold) enhanced the cytotoxicity of 5E9-gelonin for Namalwa cells but showed no effect when 5E9-gelonin was tested on HeLa cells. The potentiating effects of these agents for the cytotoxicity of free gelonin varied from marked to nonexistent, depending on the type of cells. In particular, adenovirus-2 potentiated the cytotoxicity of gelonin for HeLa cells but not for Namalwa cells. The three major adenoviral capsid proteins, penton, hexon, and fiber, were isolated. It was shown that penton potentiated the cytotoxicity of gelonin for HeLa cells and that hexon and fiber had no measurable effect on the cytotoxicity of gelonin. However, like the whole virus, penton was not able to affect the cytotoxicity of gelonin conjugates.
Mol Pharmacol 1989 Nov
PMID:Cytotoxicity of gelonin conjugated to targeting molecules: effects of weak amines, monensin, adenovirus, and adenoviral capsid proteins penton, hexon, and fiber. 253 Dec 72

Immunization of BALB/c mice with glycoproteins purified from a detergent extract of human chronic lymphocytic leukemia (CLL) cells by affinity to Lens culinaris lectin led to the production of several monoclonal antibodies with similar reactivity. One of the antibodies, 50B4, was purified and the corresponding antigen was isolated from a B-lymphoblastoid cell line extract by affinity chromatography to the 50B4-IgG immunoadsorbent. Co-purification of the antigenic activities associated with five other monoclonal antibodies was achieved. Purified and radiolabelled 50B4 antigen could be specifically immunoprecipitated not only by 50B4 but also by the other five antibodies. SDS-PAGE analysis revealed that all antibodies precipitated the same component, a polypeptide chain of apparent mol. wt 85,000 under reducing conditions. Competitive-binding studies between the purified antibodies indicated the presence of two distinct epitopes on the antigen. The epitopes, each recognized by three different antibodies, were equally accessible on the cell surface of either a B-CLL (3 X 10(5) molecules/cell), a B-lymphoblastoid cell line (11 X 10(5) molecules/cell) or two acute lymphocytic leukemia (ALL) cell lines of pre-B phenotype (5 X 10(5) and 0.8 X 10(5) molecules/cell respectively). Although the antigens purified from the strongly positive ALL cell line gave a gel pattern identical to that of the B-lymphoblastoid cell line, the antigens purified from the B-CLL extract were resolved into two distinct glycosylated polypeptides of mol. wts 85,000 and 77,000 under reducing conditions. The distribution of the antigen(s) is not restricted to cells of the B-lineage as mature T-cells and a variety of non-hematopoietic cell types express both epitopes of the antigen(s).
Mol Immunol 1985 Feb
PMID:A glycoprotein of molecular weight 85,000 on human cells of B-lineage: detection with a family of monoclonal antibodies. 257 28

The Philadelphia chromosome (t9:22;q34:q11) is found in more than 90% of patients with chronic myelogenous leukemia, in 10 to 20% of patients with acute lymphocytic leukemia, and in 1 to 2% of patients with acute myelogenous leukemia. Alternative chimeric oncogenes are formed by splicing different sets of BCR gene exons on chromosome 22 across the translocation breakpoint to a common set of ABL oncogene sequences on chromosome 9. This results in an 8.7-kilobase mRNA that encodes the P210 BCR-ABL gene product commonly found in patients with chronic myelogenous leukemia or a 7.0-kilobase mRNA that produces the P185 BCR-ABL gene product found in most Philadelphia chromosome-positive patients with acute lymphocytic leukemia. To compare the efficiency of growth stimulation by these two proteins, we derived cDNA clones for each with identical 5' and 3' untranslated regions and expressed them from retrovirus vectors. Matched stocks were compared for potency to transform immature B-lymphoid lineage precursors. The growth-stimulating effects of P185 for this cell type were found to be significantly greater than those of P210. Structural changes in BCR may regulate the effectiveness of the ABL tyrosine kinase function, as monitored by lymphocyte growth response. Changes in mitogenic potency may help to explain the more acute leukemic presentation usually associated with expression of the P185 BCR-ABL oncogene.
Mol Cell Biol 1989 May
PMID:Alternative forms of the BCR-ABL oncogene have quantitatively different potencies for stimulation of immature lymphoid cells. 274 38

In chronic myeloid leukemia and some cases of acute lymphoblastic leukemia, a 9;22 chromosome translocation has fused most of the c-abl oncogene to a gene designated bcr. To explore in vivo the biological effects of the chimeric gene, we introduced a facsimile of the translocation product, a bcr-v-abl gene, into the mouse germ line under the control of the immunoglobulin heavy-chain enhancer or a retroviral long terminal repeat. Some transgenic mice bearing either construct developed clonal lymphoid tumors. T lymphomas predominated, but some pre-B lymphomas developed. The transgenes were expressed in the tumors but not detectably in the lymphoid tissues of nontumorous transgenic animals, implying that transcription is activated by a low-frequency somatic event. These results demonstrate that bcr-v-abl is tumorigenic in vivo and provide a new animal model for lymphomagenesis.
Mol Cell Biol 1989 Jul
PMID:A bcr-v-abl oncogene induces lymphomas in transgenic mice. 278 35

Mitochondria from 25 patients with acute lymphoblastic leukemia (ALL) and 25 patients with acute myelogenous leukemia (AML) were compared in terms of their number, area, and shape index using a computer-controlled image analyzer. The number of mitochondria was greater in the AML than in the ALL patients. However, their size, as measured in electron micrographic profiles was similar in the two groups, in disagreement with conventional reports that mitochondria are small in granulocytes but large in lymphocytes. Two ALL patients had giant mitochondria. The mitochondria of the ALL cells were more irregular than those of the AML cells, and furthermore, within the ALL group, the degree of the irregularity was greater in those with a poor prognosis than in those in longstanding remission. The number of mitochondria was significantly greater in B-cell ALL than in null cell and T-cell ALL.
Virchows Arch B Cell Pathol Incl Mol Pathol 1986
PMID:Quantitative evaluation of leukemic mitochondria with a computer-controlled image analyzer. 287 44

Leukemic cells from 39 patients with acute leukemia (20 lymphocytic and 19 myelogenous) were examined by transmission electron microscopy and the nucleus and cytoplasm were measured on the micrographs with a computer-controlled image analyzer. The ratios between the areas of the nucleus and whole cell profile (nucleus/cell ratio), heterochromatin and euchromatin, the nucleolus and nucleus, and the degree of irregularity of the nucleus were compared between the two major types of leukemia studied. Acute lymphocytic leukemia (ALL) cells had a relatively larger nucleus and relatively less cytoplasm than acute myelogenous leukemia (AML) cells, and a greater proportion of the area of the nucleus was occupied by heterochromatin in ALL cells than in AML cells. According to the FAB classification, L1 cells are characterized by narrow, and L2 cells by wide cytoplasm based on light microscopic observation of smeared cells, and we confirmed these features by morphometry of May-Giemsa-stained blood smears. However, by electron microscopy there was no difference in the nucleus/cell ratio between L1 and L2 cells, this constituting a discrepancy between the results obtained by electron and light microscopic morphometry. In addition there was no difference in the degree of nuclear irregularity between L1 and L2 cells. Among AML subtypes, significant differences were observed only in the nucleus/cell ratio between M3 and M1, M2 or M4 cells, and in the heterochromatin/euchromatin ratio between M5 and M1, M2 or M3 cells. In conclusion, electron microscopic morphometry revealed marked differences between ALL and AML, but the differences among their subtypes defined by the FAB classification based on nonmorphometric light microscopy were less evident by electron microscopic morphometry.
Virchows Arch B Cell Pathol Incl Mol Pathol 1987
PMID:Morphometrical evaluation of acute leukemic cells by electron microscopy. Discrepancy between morphological characteristics in FAB classification and electron microscopic morphometry. 288 63

Granulocyte/macrophage progenitor cells (CFU-GM) and erythroid progenitor cells (BFU-E) have been assayed in peripheral blood (PB) and/or bone marrow (BM) from 12 patients with acute lymphocytic leukemia (ALL), 16 patients with chronic lymphocytic leukemia (CLL) and 31 patients with various forms of non-Hodgkin lymphoma (NHL) without BM involvement. Progenitor cell growth in PB and BM from the NHL patients did not differ statistically from controls (p greater than 0.1). CFU-GM and BFU-E per ml PB were markedly increased in ALL and CLL patients (p less than 0.001) while CFU-GM and BFU-E per plated BM cells from these patients were severely depressed (p less than 0.001). Lymphoblasts from one ALL patient failed to inhibit CFU-GM and BFU-E-derived colony growth from control PB mononuclear cells. The high levels of circulating progenitor cells in ALL and CLL patients clearly distinguish them from other cytopenic hematological malignancies, in which decreased progenitor cell levels have been demonstrated previously (acute myeloid leukemia, hairy cell leukemia). The cause of this finding and its pathophysiological implication still remains to be established.
Virchows Arch B Cell Pathol Incl Mol Pathol 1987
PMID:In vitro culture studies of granulocyte/macrophage and erythroid progenitor cells in lymphoproliferative disorders. 288 76

Human T-cell leukemia virus (HTLV)-infected cell lines derived from adult T-cell leukemia (ATL) express constitutively the receptor for Interleukin-2 (IL-2-R) and the associated antigen (Tac antigen). In contrast, the same antigen is transiently expressed by normal T-cells only after immune stimulation. Recently, it was reported that the constitutively expressed Tac antigen on ATL cells and cell lines was not down-regulated or modulated by anti-Tac antibody. Since the antigen was modulated on normal mitogen- or alloantigen-stimulated T-cells, we postulated that the regulation of IL-2-R may be abnormal on ATL cells; the synthesis of IL-2-R is continuously stimulated in these cells. A unique HTLV/ATLV(-) cell line (YT) derived from a child with acute lymphoblastic leukemia was found to express low levels of Tac antigen that could be enhanced by various stimuli, including conditioned medium (CM) derived from normal lymphocytes, but not by lectins (PHA, Con A). Of particular interest, the exposure of YT cells to CM from ATL cell lines with helper phenotype revealed the presence of factor(s) (ATL-derived factor, ADF) that augmented the synthesis and expression of IL-2-R/Tac antigen on YT cells and promoted YT cell growth. CM from HTLV(-) leukemia cell lines lacked both IL-2-R augmenting activity and a growth promoting activity. Immunoaffinity-purified IL-2 and recombinant gamma interferon also lacked IL-2-R augmenting activity. Moreover, the physicochemical analysis with Fast protein liquid chromatography (FPLC) revealed that ADF was quite different in pI point from the IL-2-R augmenting activity in CM from normal lymphocytes. These results suggested that ADF is a unique product of HTLV(+) cells. The possible relationship between ADF production, HTLV infection, and the abnormal expression of IL-2-R is suggested, and these abnormalities may be advantageous for the leukemogenesis and abnormal growth of ATL.
J Mol Cell Immunol 1985
PMID:Adult T leukemia cells produce a lymphokine that augments interleukin 2 receptor expression. 297 23


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