Kenichi Takeshita

STAT3 is a negative regulator of granulopoiesis but is not required for G-CSF-dependent differentiation

STAT3 has been described as an essential component of G-CSF-driven cell proliferation and granulopoiesis. This notion was tested by conditional gene ablation in transgenic mice. Contrary to expectation, granulocytes developed from STAT3 null bone marrow progenitors, and STAT3 null neutrophils displayed mature effector functions. Rather than a deficit in granulopoiesis, mice lacking STAT3 in their hematopoietic progenitors developed neutrophilia, and bone marrow cells were hyperresponsive to G-CSF stimulation. These studies provide direct evidence for STAT3-independent granulopoiesis and suggest that STAT3 directs a negative feedback loop necessary for controlling neutrophil numbers, possibly through induced expression of the signaling inhibitor, SOCS3.

Effect of Highly Active Antiretroviral Therapy on Survival in Patients With AIDS-Associated Pulmonary Kaposi’s Sarcoma Treated With Chemotherapy

PURPOSEnKaposis sarcoma (KS) is the most common AIDS-related malignancy. Pulmonary involvement by KS (PKS) has carried a poor prognosis with median reported survival ranging from 3 to 10 months. We studied whether the introduction of highly active antiretroviral therapy (HAART; triple antiretroviral therapy including a protease inhibitor and two reverse transcriptase inhibitors) has been associated with improved survival for AIDS patients with PKS.nnnPATIENTS AND METHODSnA retrospective study was performed of 37 consecutive patients with PKS and human immunodeficiency virus infection in the tumor registry at a large municipal hospital in New York City between 1994 to 1997. There were 16 patients from 1994 to 1995 (pre-HAART period) and 21 patients from 1996 to 1997 (post-HAART period). The primary end point was survival, which was defined as time from start of chemotherapy until death from any cause.nnnRESULTSnPatients were analyzed by the date of diagnosis (pre- v post-HAART period) and whether or not they received HAART. Kaplan-Meier analysis showed significantly better survival in patients diagnosed in the post-HAART period (P =.0025). Additional Kaplan-Meier analysis indicated that patients on HAART had substantially better survival (P <.0001). Cox multivariate analyses showed that HAART therapy was associated with a reduced risk of death (hazard ratio = 0.09; 95% confidence interval, 0.03 to 0.69).nnnCONCLUSIONnIn patients with AIDS-associated PKS and undergoing chemotherapy, administration of HAART was associated with increased survival.

MEIS1 and HOXA7 genes in human acute myeloid leukemia

Co-activation of Meisl with Hoxa7 or Hoxa9 homeobox genes by retroviral gene insertion has recently been reported to be leukemogenic in murine myeloid leukemia. In this study we determined their expression in human leukemia. Most human myeloid leukemia cell lines co-expressed MEIS1 with HOXA7 and HOXA9. Among patients with acute leukemia, 50% of AML patients expressed MEIS1, while the majority of ALL patients were negative. A total of 89.5% of patients expressing MEIS1 co-expressed HOXA7. In unadjusted models, poorer response to chemotherapy was associated with expression of HOXA7 regardless of MEIS1 status and older patients were more likely to express either gene.

Hematopoietic progenitor cell abnormalities in Hoxc-8 null mutant mice.

The mammalian Hox genes encode a family of conserved transcription factors that control the establishment of the body plan during embryogenesis. Many Hox genes are also known to be expressed in hematopoietic cells. We found that Hoxc-8, a member of the Hox C cluster, is expressed in the mouse hematopoietic organs, fetal liver and adult bone marrow. To determine the role of Hoxc-8 gene in hematopoiesis, we compared progenitor cell numbers in the fetal liver and adult bone marrow cells. We observed a significant reduction in the number of erythroid burst-forming unit (BFU-E) and in granulocyte/macrophage colony-forming unit (CFU-GM) in the Hoxc-8 null mice, although the peripheral blood cell counts were normal. The hematopoietic cells from the homozygote animals exhibited normal expansion capability in a liquid culture system, suggesting that the decreased number of progenitor cells may be due to a defect extrinsic to the hematopoietic cells, such as in the interaction with the microenvironment.

Multilineage involvement and erythropoietin-"independent" erythroid progenitor cells in a patient with systemic mastocytosis

Abstractu2002We report on a patient with systemic mastocytosis with an activating point mutation of the c-kit gene. This mutation was identical to the c-kit mutation recently described by other groups. Additionally, we found that in this patient the mutation was also present in myeloid and erythroid lineages, indicating a multilineage involvement and suggesting a clonal origin of the disease similar to that described in other myeloproliferative disorders. The erythroid involvement was further demonstrated by the presence of erythropoietin-independent erythroid progenitor cells.

Overexpression of the homeobox gene DLX-7 inhibits apoptosis by induced expression of intercellular adhesion molecule-1

OBJECTIVEnDLX genes constitute a subfamily of divergent homeobox genes. We have previously reported that inhibition of DLX-7 expression by an antisense oligonucleotide caused apoptosis in the K562 erythroleukemia cell line, which highly expresses DLX-7. In this study, we have constructed an expression vector encoding human DLX-7, and examined the effects of overexpression of DLX-7 in the IL-3-dependent lymphoid precursor cell line Ba/F3.nnnMETHODSnDLX-7 expression vector was electroporated into Ba/F3 cells, and generate a DLX-7 expressing Ba/F3 cells. Northern blot analysis was performed to determine DLX-7 gene expression. WST-1 assay was used to cell proliferation assay. To detect apoptosis, we performed TUNEL assay. Expression of cell surface adhesion molecules was examined by FACS analysis.nnnRESULTSnGrowth properties of DLX-7-transfected Ba/F3 cells in the presence of IL-3, did not differ from those of control Ba/F3 cells. However, in the absence of IL-3, DLX-7-transfected cells abrogated growth dependence on cytokines due to inhibition of apoptosis. Because adhesion properties of DLX-7-transfected cells increase, we examined expression of adhesion molecules in these cells. Expression of intercellular adhesion molecule (ICAM)-1 and ICAM-2 were markedly upregulated in DLX-7-transfected cells. Both anti-ICAM-1 antibody and anti-LFA-1 antibody blocked the aggregation of DLX-7-transfected cells. Moreover, in the absence of IL-3, cytokine-independent cell growth was blocked by anti-ICAM-1 antibody.nnnCONCLUSIONnThese results indicate that DLX-7 overexpression blocks apoptosis and that ICAM-1 expression induced by DLX-7 contributes to this antiapoptotic effect.

A DeImmunized chimeric anti-C3b/iC3b monoclonal antibody enhances rituximab-mediated killing in NHL and CLL cells via complement activation.

Complement-dependent cytotoxicity (CDC) is a key mechanism of Rituximab (RTX) action in killing non-Hodgkin’s lymphoma (NHL) cells both in vitro and probably in vivo. A DeImmunized, mouse/human chimeric monoclonal antibody (Mab), H17, specific for cell-associated complement C3 cleavage products, C3b and iC3b, was generated to enhance RTX-mediated killing of target cells by CDC. When NHL cell lines were treated with RTX and H17 in the presence of complement for 1xa0h, there was 40–70% more cell death than that observed with RTX alone. The enhancing effect of H17 was also seen over longer treatment periods. H17 was tested ex vivo against primary cells from NHL and chronic lymphocytic leukemia (CLL) patients. In RTX-resistant NHL samples, H17 enhanced RTX-mediated killing; in the remaining samples RTX + complement alone promoted more than 80% killing, and no significant enhancement was observed. The H17 antibody also increased RTX-mediated killing in four out of nine CLL samples. H17 may have therapeutic applications in NHL and CLL treatment as an adjunctive therapy to RTX. It might also enhance the activity of other therapeutic antibodies that work through CDC.

Clinical Characteristics of Gastrointestinal Lymphomas Associated with AIDS (GI-ARL) and the Impact of HAART

Abstract Purpose: The gastrointestinal (GI) tract is the most common site of extranodal disease in patients with systemic non-Hodgkin’s lymphoma (NHL). Patients with systemic NHL and GI involvement associated with AIDS (GI-ARL) have a significantly worse prognosis than those without AIDS. We studied whether the introduction of HAART is associated with improved survival in patients with GI-ARL. Patients and Method: 36 patients with GI-ARL were identified from the tumor registries of a large municipal hospital in New York City and a tertiary care facility in western New York State. Of these, 28 patients did not receive HAART and 8 were treated with HAART. The primary endpoint was survival, which was defined as time from date of diagnosis of NHL until death from any cause. Results: Patients were analyzed based on whether or not they were treated with HAART. Kaplan-Meier analysis showed significantly better survival in patients with GI-ARL who were concurrently treated with HAART (p = .014). Median survival was 5 months for the no-HAART group and 30 months for the HAART group. Conclusion: In patients with GI-ARL who were treated with chemotherapy, concurrent therapy with HAART therapy was associated with improved survival.