Hemoglobin synthesis of both adult and fetal types in a human CML cell line

Anti-Fas/CD95 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) differentially regulate apoptosis in normal and neoplastic human basophils

Basophilia is associated with allergic and parasitic diseases and advanced chronic myeloid leukemia. In the present study, we characterized the expression and function of the death receptors Fas/CD95 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors in basophils from healthy donors compared to neoplastic basophils. Peripheral blood basophils obtained from healthy donors (HD-PBB) and from patients with chronic myeloid leukemia (CML-PBB) were found to express high levels of Fas/CD95 and low levels of TRAIL-R2, whereas the basophil-like chronic myeloid leukemia cell line KU-812 expressed significant levels of TRAIL-R1 and TRAIL-R2. HD-PBB underwent apoptosis in response to anti-Fas/CD95, but showed resistance to TRAIL, unless they were co-treated with actinomycin D. Interestingly, CML-PBB and KU-812 cells exhibited the opposite response pattern with resistance to anti-Fas/CD95, but significant susceptibility to TRAIL-induced apoptosis. Our data show that anti-Fas/CD95 and TRAIL differentially regulate apoptosis of normal and neoplastic human basophils, which may direct the development of novel therapeutic strategies.

Blood cells with fetal haemoglobin (F-cells) detected by immunohistochemistry as indicators of solid tumours

AIMS

Fetal hemoglobin (HbF) is an established serological indicator of cancer. However, its distribution in tumour tissues is rarely investigated. Therefore, HbF was studied immunohistologically in different cancers characterised by high blood HbF concentrations.

METHODS

Anti-HbF was immunoaffinity purified and used to study HbF immunohistochemically in the following cancers: germ cell tumour (GCT), trophoblastic disease (TD), lymphoma, myelodysplastic syndrome (MDS), multiple myeloma (MM), and ovarian adenocarcinoma (OA).

RESULTS

In GCT a distinction was made between tumours substantially without HbF positive red blood cells (F-RBC) and those with F-RBC. Those without F-RBC were non-metastatic mature teratomas and dermoid cysts. Those containing F-RBC were mainly embryonal carcinomas and metastatic teratomas. HbF positive myeloid cells (F-MLC), HbF positive normoblasts (F-NBS), and F-RBC were common in the bone marrow and in the lymphoid tissues of lymphoma, MDS, and MM. In TD, normal and nucleated F-RBC were seen in the trophoblastic villi in one case with incomplete molar pregnancy (ICM) but not in other cases of ICM and complete molar pregnancy. However, F-RBC and F-MLC were seen in the decidua of both types of TD. Generally, F-cells were observed either within blood vessels or concentrated in certain areas of the neoplastic tissue.

CONCLUSIONS

HbF was evaluated as an inducible marker within different tumour tissue blood cells. The dual distribution of these cells-circulating in the blood or concentrated in areas of the neoplastic tissues-might reflect the two independent serological indicators of HbF: one in whole blood and the other in plasma of patients with cancer.

Expression of transferrin receptor 2 in normal and neoplastic hematopoietic cells

Iron is essential for cell proliferation, heme synthesis, and a variety of cellular metabolic processes. In most cells, transferrin receptor-mediated endocytosis is a major pathway for cellular iron uptake. Recently, transferrin receptor 2 (TfR2), another receptor for transferrin, was cloned. High levels of expression of TfR2 messenger RNA (mRNA) occur in the liver, as well as in HepG2 (a hepatoma cell line) and K562 (an erythroid leukemia cell line). In this study, TfR2 mRNA expression was analyzed in hematological cell lines, normal erythroid cells at various stages of differentiation, and leukemia and preleukemia cells. High levels of TfR2 expression occurred in all of the erythroid cell lines that were examined. Erythroid-specific expression of TfR2 protein in bone marrow cells was confirmed by immunohistochemical staining. Expression of TfR2 mRNA was high in normal CD34(+) erythroid precursor cells, and levels decreased during erythroid differentiation in vitro. Levels of expression of TfR2-alpha mRNA were significantly higher in erythroleukemia (M6) marrow samples than in nonmalignant control marrow samples. In addition, relatively higher levels of TfR2-alpha mRNA expression occurred in some samples of myelodysplastic syndrome that had erythroid hyperplasia in bone marrow, acute myelogenous leukemia M1, M2, and chronic myelogenous leukemia. Expression profiles of normal members of the erythroid lineage suggest that TfR2-alpha may be a useful marker of early erythroid precursor cells. The clinical significance of TfR2-alpha expression in leukemia cells remains to be determined.

Significance of pH on differentiation of human erythroid cell lines

As physiological factors and compounds, BSA and/or higher pH of the culture medium could induce the erythroid differentiation of cells. Optimum pH values of the culture medium for higher spontaneous differentiation of KU-812 and K562 cells after 7 days cultivation were 7.5 and 7.6, respectively. The synergistic effects on the differentiation were observed by exposure to hemin under the higher pH condition. In the presence of BSA, 25% of KU-812 and 40% of K562 cells became benzidine positive. Synergistic effects of BSA and the higher pH of the medium were also observed.

A novel C-T transition within the distal CCAAT motif of the G gamma-globin gene in the Japanese HPFH: implication of factor binding in elevated fetal globin expression

Hereditary persistence of fetal hemoglobin (HPFH) is a condition characterized by the continued expression of the fetal globin gene in adulthood. Both deletional and nondeletional forms have been described. We studied one Japanese family with two different nondeletional forms of HPFH. Analysis of polymorphic restriction sites in the beta-globin gene cluster suggested that one affecting both G gamma and A gamma globin expression in two members of the family could be associated with unknown conditions not linked to the beta-globin gene loci. Characterization by the polymerase chain reaction (PCR) of another form producing a G gamma-HPFH phenotype in two other members demonstrated a novel C-T transition at the nucleotide -114 within the distal CCAAT motif of the G gamma-globin gene. Using gel retardation assays on various nuclear extracts, we also demonstrated that this novel mutation abolishes the binding of the ubiquitous CCAAT binding factor, CP1 to the distal CCAAT motif of the gamma-globin gene but does not affect the binding of any erythroid specific factor, thereby suggesting a possible role for CP1 in the developmental regulation of fetal globin expression.

Lineage non-specific down regulation of P210bcr/abl in the CML cell line, KU-812-F, during differentiation

CML cell line, KU-812-F, originally established from a patient with Philadelphia-chromosome-positive chronic myelocytic leukemia has maintained the ability to differentiate into both granuloid (basophilic) and erythroid lineages. The expression of P210bcr/abl in KU-812-F cells during differentiation was studied by immunoblotting and immunoprecipitation. Immunoblotting with anti-phosphotyrosine sera revealed the down-regulation of P210bcr/abl in both granuloid and erythroid lineages. Immunoprecipitation with anti-abl antibodies of 35S-methionine-labelled cells revealed a reduced rate of synthesis of P210bcr/abl protein. Cytotoxic agents that caused growth inhibition of the cells did not alter the expression of P210bcr/abl. These results indicate that the down regulation of P210bcr/abl protein is a lineage non-specific event accompanied by differentiation.