Decreases in Ikaros activity correlate with blast crisis in patients with chronic myelogenous leukemia.

Gene targeting studies in mice have shown that the lack of Ikaros activity leads to T-cell hyperproliferation and T-cell neoplasia, establishing the Ikaros gene as a tumor suppressor gene in mice. This prompted us to investigate whether mutations in Ikaros play a role in human hematological malignancies. Reverse transcription-PCR was used to determine the relative expression levels of Ikaros isoforms in a panel of human leukemia/lymphoma cell lines and human bone marrow samples from patients with hematological malignancies.

History and classification of human leukemia-lymphoma cell lines.

Continuous human leukemia-lymphoma cell lines have become indispensable tools in hematological research since the establishment of the first human lymphoma cell line Raji in 1963. We summarize here historical landmarks in the establishment of unique leukemia-lymphoma-derived cell lines from the various cell lineages; their special importance in hematopoietic research is emphasized. The first cell lines were derived from African Burkitt lymphomas and were found to integrate the Epstein-Barr virus in their genome leading to the discovery and isolation of this virus.

Proposals for the characterization and description of new human leukemia-lymphoma cell lines.

Continuous human leukemia-lymphoma cell lines have become invaluable tools for hematological research as they provide an unlimited amount of cellular material. The first human lymphoma cell line Raji was established in 1963; since then several hundred leukemia-lymphoma cell lines spanning almost the whole spectrum of hematopoietic cell lineages (except for dendritric cells) have been described. The cardinal features of leukemia-lymphoma cell lines are their monoclonal origin, arrest of differentiation, and (growth factor-independent or -dependent) unlimited proliferation.

Comparison of two methods of staining apoptotic cells of leukemia cell lines. Terminal deoxynucleotidyl transferase and DNA polymerase I reactions.

We compared two methods to stain apoptotic cells, one using terminal deoxynucleotidyl transferase (TDT), the other DNA polymerase I, using leukemia cell lines treated with anti-Fas monoclonal antibody (MAb). Both TDT and polymerase I strongly reacted with fragmented nuclei of apoptotic MOLT-16 and Jurkat cells, but only polymerase I strongly reacted with nonfragmented nuclei of early apoptotic cells. Anti-Fas MAb-treated MOLT-4 cells showed morphological changes corresponding to early apoptosis and were strongly positive for polymerase I only.

Induction of hepatocyte growth factor/scatter factor by interferon-gamma in human leukemia cells.

Induction of hepatocyte growth factor/scatter factor (HGF/SF) may be one of the critical steps in organ regeneration, wound healing, and embryogenesis. We previously reported the production of HGF/SF from various human leukemia cell lines and a high level of the growth factor in blood and bone marrow plasma from patients with various types of leukemia. We determined here the effects of hematopoietic cytokines on HGF/SF production in human leukemia cell lines, KG-1, a myeloid cell line, and RPMI-8226, a B cell line.

A murine monoclonal antibody (928) recognizing a new epitope formed with a combination of HLA-DPA1*0201 and DPB1*0301 gene products.

A murine monoclonal antibody (mAb), 928, that recognizes a cell surface antigen (928 Ag) on a human Epstein-Barr virus-transformed fetal liver-derived lymphoid progenitor cell line (FL4.4) was generated. The 928 mAb reacted with only FL4.

Selective expression of mRNA coding for the truncated form of erythropoietin receptor in hematopoietic cells and its decrease in patients with polycythemia vera.

The mRNA encoding full-length erythropoietin (EPO) receptor (EPOR-F) comprises exons I through VIII. Another membrane-bound EPOR (EPOR-T) isoform has a truncated cytoplasmic region and is encoded by the mRNA containing unspliced intron VII (EPOR-T mRNA). EPOR-T is believed to have a dominantly negative function against EPOR-F.

In vitro study using leukemia cell line panel to demonstrate rapid thymic T cell death due to contact with HIV-1 carrier cell clones.

A rapid (within 1 h) and profound cytotoxic cell death of immature TdT+CD4+CD8+ and/or TdT+CD4+ thymic T cell type leukemia cell lines, and of normal thymocyte populations rich in TdT+CD4+CD8+ cells was induced by contact with some human immunodeficiency virus type-1 (HIV-1) carrier T cell clones. This cytotoxic reaction, without requiring a complete viral replication cycle in the thymic T cells, did not occur in any mature CD4+CD8+ and/or CD4+ T cells which are otherwise permissive for virus infection. Although it was not an antigen-specific cytotoxic reaction, the rapid and profound thymic T cell destruction was shown, at the individual clonal level, to be triggered specifically by the binding of CD4 molecules on thymic T cells with gp120/gp160 on HIV-1 carrier clones.

Acquired cytotoxic activity of CD8+ HIV-1IIIB carrier immature T cell clones specific to CD4+CD8+ (parental) human T cell clones and normal thymocytes.

By infecting human leukemia cell lines in vitro with HIV-1IIIB' a number of HIV-1 carrier clones were generated. Among them, 5 of 13 CD8+ HIV-1 carrier T cell clones were shown to acquire a rapid cytotoxic activity (within 1 hour) specific to TdT+CD4+CD8+ immature T cells including normal thymocytes. This novel cytotoxic reaction, without requiring virus infection and indicating a rapid T cell precursor elimination during active lymphopoiesis, suggests a mechanism responsible for mature CD4+ T cell depletion in HIV-1 infected individuals.

Interferon-alpha and -gamma differentially reduce rapid immature T-cell death by contact with HIV-1 carrier cell clones in vitro.

The non-antigen specific rapid cytotoxic (CT) death of immature TdT+CD4+CD8+ T cells due to contact with HIV-1 carrier T-cell clones we have found recently is a novel phenomenon. The effects of interferons (IFN) on this CT reaction were studied in vitro. Treatment of the HIV-1 carrier clones, referred to as "effectors," with IFN-alpha but not IFN-gamma, or of the susceptible immature TdT+CD4+CD8+ T cells, referred to as "targets," with IFN-gamma but not IFN-alpha, for 24 hr prior to CT testing was found to reduce the CT reaction.

Genomic analysis of a new mammalian distal-less gene: Dlx7.

We have cloned a new Dlx gene (Dlx7) from human and mouse that may represent the mammalian orthologue of the newt gene NvHBox-5. The homeodomains of these genes are highly similar to all other vertebrate Dlx genes, and regions of similarity also exist between mammalian Dlx7 and a subset of vertebrate Dlx genes downstream of the homeodomain. The sequence divergence between human and mouse Dlx7 in these regions is greater than that predicted from comparisons of other vertebrate Dlx genes, however, and there is little sequence similarity upstream of the homeodomain both between these two genes and with other Dlx genes.

Abnormal expression of Evi-1 gene in human leukemias.

The human Evi-1 gene located on chromosome 3q26, encodes a zinc finger protein that functions as a transcription factor. It was frequently overexpressed in leukemias having 3q26 abnormalities such as t(3;3)(q21;q26) and inv(3)(q21 q26), and subjected to structural alteration in t(3;21)(q26;q22). In addition, recent studies indicated that several cases of leukemias without 3q26 abnormalities also expressed Evi-1 gene.

Metastatic potential of lymphoma/leukemia cell lines in SCID mice is closely related to expression of CD44.

To investigate whether the lymphocyte homing receptors, adhesion molecules regulating normal lymphocyte traffic, influence the dissemination of lymphoma cells, 24 lymphoma/leukemia cell lines were inoculated into SCID mice subcutaneously, and the correlation between the expression of the adhesion molecules and the metastatic potential of the cell lines was examined. Among the six adhesion molecules examined (LFA-1, ICAM-1, CLA, VLA-4, L-selectin and CD44), L-selectin increased the incidence of lymph node metastasis, and CD44 expression was related to both lymph node and organ (hematogenous) metastasis. A monoclonal antibody to the standard form of CD44 (CD44s), Hermes-3, inhibited the local growth and remote metastasis of CD44+ cell lines.

Autocrine loop through cholecystokinin-B/gastrin receptors involved in growth of human leukemia cells.

The cholecystokinin (CCK)-B/gastrin receptor binds two brain-gut hormones, CCK and gastrin, with high affinities. These peptides have a trophic effect on gastrointestinal cells expressing the receptor in vivo as well as in vitro. Recently, this receptor mRNA was reported to be expressed in immunocytes localized in the lamina propria of normal rat stomach mucosa.

Purification and primary amino acid sequence of a novel neutrophil chemotactic factor LECT2.

We purified a neutrophil chemotactic factor from a culture fluid of the PHA-activated human T-cell leukemia SKW-3 cells. The factor showed a 16-kDa basic protein by Tricin-SDS-polyacrylamide gel electorophoresis and analysis of amino acid composition. The primary amino acid sequence revealed that the chemotactic factor was significantly different from other known chemotactic factors, indicating a novel protein designated LECT2.

Structurally altered Evi-1 protein generated in the 3q21q26 syndrome.

Overexpression of the Evi-1 gene appears to be a consistent feature of the 3q21q26 syndrome, an association of myeloid leukemias/myelodysplastic syndrome with a specific chromosomal aberration involving both 3q21 and 3q26, such as t(3;3)(q21;q26) or inv(3)(q21q26). The rearrangement in 3q26 has been reported to occur near the Evi-1 locus, implicating that it is the critical gene deregulated in the 3q21q26 syndrome. Here we present a structural abnormality of Evi-1 protein in a case with the 3q21q26 syndrome.

Molecular characterization of a chromosome translocation breakpoint t(11;14)(p13;q11) from the cell line KOPT-K1.

Recurrent chromosome translocations involving 11p13 and 14q11 are found in 5-10% of cases of T-ALL. The gene involved in the translocation on chromosome 14 is the T cell antigen receptor alpha or delta. The putative oncogene on chromosome 11 is rhombotin 2 (RBTN2)/translocated in T cell gene 2 (ttg-2), a member of the LIM family of proteins.

Hepatocyte growth factor--pleiotropic cytokine produced by human leukemia cells.

Hepatocyte growth factor (HGF) was identified, purified and molecularly cloned as a potent mitogen for mature rat hepatocytes in primary culture. It is one of the largest cytokines and is composed of disulfide-linked subunits of approximately 60 (heavy chain) and 35 kilodaltons (light chain). Recent observations revealed that HGF is mitogenic to various epithelial cells other than hepatocytes and to endothelial cells, and that it also acts as a motogen, morphogen and tumor-suppressor as well as a mitogen.

Expression of 18.6/CD23 antigen on human lymphoid progenitor cell lines and phorbol 12-myristate 13-acetate (PMA)-induced microglia-shaped cells.

The nature of lymphoid progenitors and factor(s) determining commitment to either the T- or B-lymphocyte pathway are poorly understood in the human system. In this study, we generated a monoclonal antibody (MoAb), 18.6, that recognizes a cell surface antigen on a human lymphoid progenitor cell line (FL4.

Murine monoclonal antibodies (MCS-1 and MCS-2) reactive with human myeloid leukemia cells.

In an attempt to identify the antigens expressed on human myeloid leukemia cells, two murine monoclonal antibodies (mAb) designated as MCS-1 (isotype; IgG3) and MCS-2 (IgG1) were raised. MCS-1 reacted with peripheral blood granulocytes, but not with monocytes, whereas MCS-2 reacted with both granulocytes and monocytes. The incidence of MCS-1 and MCS-2 reactivity with the cells from a total of 121 patients with various type of leukemias was as follows: 25/46 (54%) and 39/47 (83%) in acute myeloblastic leukemia and acute monoblastic leukemia, 8/16 and 16/16 in chronic myeloid leukemia in blastic crisis (CML-BC) of myeloid type, 0/7 and 2/7 in CML-BC of lymphoid type, 0/26 and 2/32 in acute lymphoblastic leukemia (ALL), 7/7 and 7/7 in chronic phase of CML, respectively.

Interleukin-1 and interferon-alpha augment interleukin-2 (IL-2) production by distinct mechanisms at the IL-2 mRNA level.

The production of interleukin-2 (IL-2) by phytohemaglutinin (PHA)-stimulated cells of human leukemia T cell line MOLT-16 can be significantly increased by interleukin-1 (IL-1) or interferon-alpha (IFN-alpha). The enhancing effect of IL-1 and IFN-alpha on IL-2 production was studied at the IL-2 mRNA level. We show that IL-1 enhances considerably and transiently, with the maximum level between 1 and 2 hr after stimulation, the expression of IL-2 mRNA in the PHA-stimulated cells.

Establishment of multiple leukemia cell lines with diverse myeloid and/or megakaryoblastoid characteristics from a single Ph1 positive chronic myelogenous leukemia blood sample.

Seven cell lines, MOLM-6, -7, -8, -9, -10, -11 and -12, were established from a single blood sample from a patient with chronic myelogenous leukemia (CML) in blastic phase having the Ph1 chromosome abnormality. Based on immunophenotyping, two of these seven cell lines, MOLM-7 and -11, represented the megakaryoblastoid lineage, and the other five cell lines represented two different maturation stages of the myeloid lineage.

Expression of Bcl-2 protein and Fas antigen in non-Hodgkin's lymphomas.

Expression of Bcl-2 protein and Fas antigens was analyzed in 12 cases of follicular lymphoma and 32 cases of diffuse lymphoma, including 22 B-cell and 10 T-cell lymphomas. It was shown that 75% of follicular lymphomas had clear expression of both Bcl-2 protein and Fas antigen. Thus, follicular lymphomas may have a growth advantage due to their high expression of Bcl-2 protein, which tended to impede apoptosis mediated by Fas antigen.

Differential platelet-associated factor gene expression by a panel of human cell lines with megakaryoblastic properties after treatment with phorbol myristate acetate.

Four human megakaryocytoid cell lines, namely MOLM-1, MOLM-7, MEG-01 and HEL, were treated with phorbol 12-myristate 13-acetate (PMA) and expression of the platelet-derived growth factor (PDGF) A chain, von Willebrand factor (vWF) and endothelial cell growth factor (ECGF) genes was examined by the reverse transcriptase-polymerase chain reaction (RT-PCR) using specific primers. The gene for PDGF A chain is constitutively weakly expressed by MEG-01 cells and strong expression is induced in MEG-01, MOLM-1 and MOLM-7 but not in HEL cells after treatment with PMA for three days. All four cell lines express the vWF gene both constitutively and after exposure to PMA.