Adhesion to fibronectin induces megakaryocytic differentiation of JAS-REN cells.

BACKGROUND: Binding of integrins to the extracellular matrix elicits various responses. We have previously reported a megakaryocytic-erythroid cell line (JAS-R) that showed phenotypic changes after adhesion to plastic dishes. However, the matrix protein and the mechanism responsible for megakaryocytic differentiation still remain unknown. MATERIALS AND METHODS: JAS-REN (erythroid) cells were cultured on dishes coated with various proteins. The cells were treated with RGDS, a tetrapeptide ligand to integrins, or phorbol ester (12-o-tetradecanoylphorbol-13-acetate, TPA) for 48 hours and then were harvested. Subsequently, the cell surface markers were analyzed using flow cytometry and gene expression was studied by RT-PCR. RESULTS: The JAS-REN cells adhered to fibronectin-coated dishes, but showed poor adhesion to dishes coated with collagen, laminin or poly-D-lysine. The TPA-stimulated JAS-REN cells showed an increase in the expression of integrin alphaIIbbeta3 complex (CD41a) and integrin beta3 (CD61), while glycophorin A (CD235a) expression was decreased. JAS-REN cells that were adherent to fibronectin-coated dishes also showed a similar pattern of phenotype to TPA-treated cells, but the changes were not so prominent. RT-PCR revealed that TPA treatment altered the gene expression profile of JAS-REN cells, making it similar to that of JAS-RAD (megakaryocytic) cells. The RGDS-treated and fibronectin adherent JAS-REN cells also showed a mostly similar expression profile to JAS-RAD cells, but these two stimuli did not alter the gene expression profile as TPA stimulation did. Transcription factors, FLI1 and GFI1, were induced by all stimuli. CONCLUSION: Signals triggered by adhesion to fibronectin result in the induction of FLI1 that may play a pivotal role in the lineage shift of JAS-REN cells from erythroid to megakaryocytic.

Segregation of megakaryocytic or erythroid cells from a megakaryocytic leukemia cell line (JAS-R) by adhesion during culture.

Adhesion is one of the important biologic characteristics of leukemic cells. We previously reported a new megakaryocytic-erythroid cell line, JAS-R. In this study, JAS-R cells were segregated into two types by the differences of attachment to culture dishes. One type (designated as JAS-RAD cells) adhered to the substratum of the culture dishes, while the other (JAS-REN cells) grew as a single-cell suspension. Adhesion of JAS-RAD was inhibited by treatment with RGDS oligopeptide. Flow cytometric analysis revealed that JAS-RAD cells had high expression of CD41a and CD61 versus low CD235a expression, and JAS-REN showed low expression of CD41a, and CD61, and high CD235a. The two phenotypes were reciprocally exchangeable by selecting adherent or suspended cells from each type of culture. Microarray analysis and RT-PCR revealed that JAS-RAD cells expressed four major alpha-granule genes and JAS-REN cells expressed beta-globin. Interestingly, erythropoietin was only secreted by JAS-RAD cells. With regard to transcription factors, it was shown that GFI1, FLI1 and RUNX1 were strongly expressed in JAS-RAD cells while GATA1, FOG1 and NFE2 were equally expressed by both types. These findings indicate that adhesion via integrins is related to the phenotypic shift of JAS-R cells between megakaryocytic and erythroid lineages.

Diffuse large B-cell lymphoma arising independently to lymphoplasmacytic lymphoma: a case of two lymphomas.

Richter's syndrome occurs in 5-10% of patients with chronic lymphocytic leukemia, either by transformation of the primary neoplastic lymphocyte, or as a distinct B-cell neoplasm. We report a Japanese patient with lymphoplasmacytic lymphoma in whom a diffuse large B-cell lymphoma developed after treatment with rituximab. Molecular examination on immunoglobulin VH genes revealed that the lymphomas had arisen in two separate clones. We reviewed clinical case reports in literature, and found 30-40% of cases with Richter's syndrome and composite lymphoma had a second B-cell lymphoma of a different origin.

Beneficial effect of combination therapy with antihypertensive drugs in patients with hypertension.

BACKGROUND: Cardiac hypertrophy and failure are major complications of hypertension. OBJECTIVES: The beneficial effect of treatment with antihypertensive drugs on serum levels of brain natriuretic peptide (BNP) was examined in patients with essential hypertension. METHODS: Antihypertensive drugs were administered to 88 hypertensive patients (44 diabetic and 44 nondiabetic) whose systolic blood pressure was greater than 140 mmHg and/or diastolic blood pressure was greater than 90 mmHg. Other antihypertensive drugs were added every two months until the blood pressure fell below 130/85 mmHg. Candesartan, benidipine, bisoprolol or celiprolol, and bunazosin were administered in this order. RESULTS: The mean systolic blood pressure was reduced from 163.7+/-11.6 mmHg to 121.8+/-7.5 mmHg after 12 months in patients with diabetes and from 167.6+/-12.3 mmHg to 122.8+/-7.5 mmHg in patients without diabetes. The mean diastolic blood pressure was also significantly reduced in patients with and without diabetes. Serum BNP levels were reduced from 52.2+/-38.8 pg/mL to 38.8+/-30.9 pg/mL in patients with diabetes and from 47.1+/-34.2 pg/mL to 35.8+/-22.5 pg/mL in patients without diabetes. In patients older than 70 years of age, serum BNP levels were reduced from 56.3+/-39.3 pg/mL to 40.2+/-23.0 pg/mL in those with diabetes and from 54.6+/-32.9 pg/mL to 38.0+/-16.0 pg/mL in those without diabetes. CONCLUSIONS: These results indicate that combination therapy with antihypertensive drugs is usually necessary to reduce blood pressure to below 130/85 mmHg and to improve serum BNP levels.

JAS-R, a new megakaryo-erythroid leukemic cell line that secretes erythropoietin.

BACKGROUND: The processes of leukemogenesis and differentiation of the megakaryo-erythroid lineage remain poorly understood. Leukemic cell lines derived from megakaryocytic leukemia are valuable reagents for studies on these events. MATERIALS AND METHODS: A new cell line, JAS-R, was established from a 64-year-old patient with acute megakaryocytic leukemia (AML M7). Its characteristics were studied by morphological, immunophenotypic and molecular biological analysis. RESULTS: Immunophenotyping showed that the JAS-R cells were positive for CD33, CD41 and CD61, as well as moderately to weakly positive for CD4, CD7, CD13 and glycophorin A. Chromosomal analysis revealed a composite karyotype, but no major translocation abnormalities were observed. Electron microscopy disclosed that the JAS-R cells had numerous surface blebs and some cells also had alpha-granules and demarcation membranes. The mRNAs of 4 major proteins (platelet factor 4, beta-thromboglobulin, selectin-P and thrombospondin 1) found in alpha-granules were all expressed by the JAS-R cells. In particular, expression of platelet factor 4 was high. To further characterize JAS-R cells, comparison with 4 other megakaryo-etythroid cell lines (CMK, MEG-01, K562 and KU812) was done by gene expression profiling using an oligo-DNA microarray. The results showed that JAS-R was a distinctive cell line. It was noteworthy that the JAS-R cells secreted erythropoietin and expressed erythropoietin receptor. A neutralizing antibody for erythropoietin partly inhibited the proliferation of the cells. CONCLUSION: JAS-R may be a useful cell line for investigating the differentiation and leukemogenesis of megakaryo-erythroid cells and for studying the influence of erythropoietin on these cells.

Cardiovascular disorders in patients with diabetes mellitus.

Diabetes mellitus is a disease with multiorgan involvement. Besides retinopathy, nephropathy and peripheral neuropathy induced by microangiopathy, both cardiovascular and cerebrovascular complications are significant. Both cardiomyopathy and coronary artery disease are observed in patients with diabetes, and the latter is clinically more important because of its high incidence and seriousness.

Both NUP98/TOP1 and TOP1/NUP98 transcripts are detected in a de novo AML with t(11;20)(p15;q11).

The NUP98 gene is involved in several chromosomal abnormalities associated with acute leukemia. The recurrent t(11;20)(p15;q11) chromosomal translocation results in generation of the NUP98/TOP1 chimeric gene. This abnormality has been observed primarily in therapy-related leukemias, and TOP1/NUP98 transcripts have not been demonstrated. We describe a case of de novo acute myeloid leukemia with t(11;20)(p15;q11), with no known history of exposure to chemicals. The translocation occurred in intron 13 of NUP98 and intron 7 of TOP1, as in the three previously reported cases. The breakpoint in NUP98 was exactly the same as that found in a previously reported case. In addition, a reciprocal TOP1/NUP98 transcript was detected for the first time in our patient.

No V(H) somatic hypermutation was detected in B-cells of a patient with macroglobulinemia due to splenic marginal zone lymphoma.

B-cell diseases are classified on the basis of the normal differentiation stages. We report here a case of a patient with a long history of leukocytosis, splenomegaly without lymphadenopathy, and hyperviscosity symptoms. Clinically, the patient's diagnosis was leukemic Waldenstrom macroglobulinemia. Chromosomal analysis revealed translocation t(2;7)(p11;q22) along with disease progression. Death occurred from pulmonary infection at 46 months after the initial presentation. At autopsy, malignant lymphocytes were found in the marginal areas of the spleen with spreading to the bone marrow and the liver. The histologic findings were consistent with splenic marginal zone lymphoma. We examined the sequences of the immunoglobulin V(H) gene in cells from the initial peripheral blood and from the spleen at autopsy and found that the sequences were identical and had no somatic hypermutation. Macroglobulinemia can occur in various B-cell disorders, including splenic marginal zone lymphoma, even with the transformation of unmutated B-lymphocytes.