Histone deacetylase inhibitor FR901228 enhances adenovirus infection of hematopoietic cells

Adenovirus infection of hematopoietic cells frequently requires high virus concentrations and long incubation times to obtain moderate infection levels because these cells have low levels of Coxsackie and adenovirus receptor (CAR) and alpha(v) integrin. The effect of treatment with FR901228 (depsipeptide), a histone deacetylase inhibitor in phase 2 clinical trials, was studied in K562 cells, granulocyte-colony-stimulating factor-mobilized peripheral blood mononuclear cells (PBMCs), and CD34+ peripheral blood stem cells (PBSCs). FR901228 increased CAR and alpha(v) integrin RNA levels and histone H3 acetylation. FR901228 treatment before adenovirus infection was associated with at least a 10-fold increase in transgene expression from a beta-galactosidase-expressing adenoviral vector. More than 80% of the PBMCs or CD34+ PBSCs from 7 different donors were beta-galactosidase-positive after adenovirus infection with a multiplicity of infection of 10 for 60 minutes. Increased CAR, alpha(v) integrin, and acetylated histone H3 levels were observed in PBMCs from a patient treated with FR901228. These studies suggest that FR901228 can increase the efficiency of adenoviral infection in hematopoietic cells.     

Effect of histone deacetylase inhibitor valproic acid on progenitor cells of acute myeloid leukemia

Histone deacetylase inhibitor valproic acid (VPA) was recently shown to enhance proliferation and self-renewal of normal hematopoietic stem cells, raising the possibility that VPA may also support growth of leukemic progenitor cells (LPC). Here, VPA maintains a significantly higher proportion of CD34+ LPC and colony forming units compared to control cultures in six AML samples, but selectively reduces leukemic cell numbers in another AML sample with expression of AML1/ETO. Our data suggest a differential effect of VPA on the small population of AML progenitor cells and the bulk of aberrantly differentiated blasts in the majority of AML samples tested.     

Induction of differentiation in blast cells and leukemia colony-forming cells from patients with acute myeloid leukemia

The characteristic lesion in acute myeloid leukemia (AML) is the failure of myeloid cells to differentiate normally, leading to the accumulation of immature blast cells (BC) in the bone marrow. We determined whether BC and leukemia colony-forming cells (L-CFC) from AML patients could differentiate in vitro after short-term culture with interferon-gamma (IFN gamma), 1,25 dihydroxyvitamin D3 (D3), retinoic acid (RA), tumor necrosis factor-alpha (TNF alpha), and granulocyte-monocyte colony-stimulating factor (GM-CSF). Expression of myeloid differentiation antigens CD15, CD14, CD33, and p124 was determined on the BC by immunofluorescence and on the L-CFC by monoclonal antibody (MoAb) and complement (C')-mediated cytotoxicity followed by cloning in methylcellulose. We found that 26 of 39 (67%) cases demonstrated changes in the expression of myeloid differentiation antigens on the BC, and 6 of 7 (86%) cases showed an altered L-CFC myeloid antigen phenotype after short-term culture with differentiating agents. Alterations in myeloid antigen expression in the L-CFC population correlated with a reduction in L-CFC cloning potential. In the BC, alterations of myeloid differentiation antigens occurred in a manner consistent with those observed during normal myelopoiesis. For example, CD14 antigen expression (a late-stage monocyte antigen) increased on BC from 12 of 39 (31%) cases, and p124 (an antigen expressed both by myeloid progenitor cells and by a subset of monocytes) increased on 15 of 39 (38%) cases. Changes in the expression of CD33 antigens (expressed normally by myeloid progenitor cells and by mature monocytes) on the BC were variable, with 7 of 29 cases (24%) showing a decrease and 7 of 29 cases (24%) showing an increase. When comparisons were made between pairs of differentiation agents that caused the altered expression of an antigen on either the BC or L-CFC of a patient, the majority of changes were in the same direction (either both "increased" or both "decreased"). This suggests that the direction of antigen change is characteristic of the leukemia cell subpopulation for each patient and not of the stimulatory agent. This study demonstrates that cells from more than two thirds of AML cases examined responded to various differentiation agents in vitro as measured by changes in the expression of myeloid cell-associated surface antigens and by alterations in cloning potential of the L-CFC, a finding of potential clinical significance.     

Role of allogeneic and autologous hematopoietic stem cell transplantation in acute myeloid leukemia

Most younger patients with acute myeloid leukemia will enter remission of disease. Prevention of relapse is now the central therapeutic issue. A number of factors predict the risk of relapse, the most powerful of which is cytogenetics. Both allogeneic and autologous transplantation have been extensively used as remission consolidation, but intensive chemotherapy has also provided improved results such that the choice of consolidation treatment is not clear. Recent prospective trials of allogeneic and autologous transplantation with careful analysis have not always shown a survival benefit, although both approaches have significantly reduced relapse risk. In analysis where relapse risk is taken into account based on cytogenetics, there is little evidence of the benefit of transplantation in good-risk patients, partly because patients in this group who relapse can then undergo successful salvage therapy. The results are still uncertain in standard-risk patients, so transplantation should continue to be used in the context of a trial. Poor-risk patients have a higher failure rate after transplantation, and for these patients novel approaches are required.     

Evidence for a pre-existing telomere deficit in non-clonal hematopoietic stem cells in patients with acute myeloid leukemia

Telomere shortening represents an established mechanism connecting aging and cancer development. We sequentially analyzed telomere length (TL) of 49 acute myeloid leukemia (AML) patients at diagnosis (n = 24), once they achieved complete cytological remission (CCR) and/or during refractory disease or relapse and after 1-year follow-up, with all patients having at least two sequential samples. TL was analyzed by monochrome multiplex quantitative polymerase chain reaction. We have observed substantially shortened TL in the cells of patients at diagnosis compared to age-adjusted controls. In patients reaching CCR after chemotherapy, telomere shortening was less pronounced than in persistence or relapse but still significantly shortened compared to controls. We estimate patients harboring approximately 20 years of premature telomere loss compared to healthy aged-matched subjects at the time of AML onset. Our data indicate a pre-existing telomere deficit in non-clonal hematopoiesis of AML patients providing a link between age and AML development.     

Effects of various recombinant human hematopoietic growth factors on proliferation of blast cells in acute myeloid leukemia in vitro]

In vitro proliferative response of the blast cells from 21 AML patients to hematopoietic growth factors (IL-3, GM-CSF, G-CSF and MCSF) was investigated. Proliferation of AML cells in the majority of cases was induced or promoted by one or more CSFs, among which the stimulation of IL-3 was the most effective. Spontaneous proliferation of the blast cells was also observed in half of the cases and could be inhibited as well as promoted by some CSFs. It is suggested that in vitro proliferation of AML cells varies from patient to patient and that CSF plays important roles in leukemogenesis.     

Clinical course of juvenile myelomonocytic leukemia in the blast crisis phase treated by acute myeloid leukemia-oriented chemotherapy and allogeneic hematopoietic stem cell transplantation

Juvenile myelomonocytic leukemia (JMML) is a mixed myeloproliferative and myelodysplastic disorder that occurs in early childhood. The clinical course of JMML is highly variable. A third of patients follow a relatively indolent course, although approximately 15 % cases are thought to develop acute myeloid leukemia, referred to as blast crisis. The etiology and clinical characteristics of blast crisis remain unclear. We document the case of a 27-month-old boy who presented with hepatosplenomegaly, skin rash, and lymphadenopathy. An initial diagnosis of acute erythroid leukemia was made according to the French–American–British classification. Following estimation of hypersensitivity to GM-CSF and genetic analysis of PTPN11, he was diagnosed with JMML in the blast crisis phase. Although he had several poor prognostic factors, including monosomy 7 and high HbF percentage, he achieved partial remission after treatment with acute myeloid leukemia-oriented chemotherapy followed by allogeneic hematopoietic stem cell transplantation. He has been in complete remission for over 6 years.     

异基因造血干细胞移植治疗43例慢性粒细胞白血病疗效分析

目的:评价采用一种新预处理方案行异基因造血干细胞移植(allo-HSCT)治疗慢性粒细胞白血病(CML)患者的疗效。方法:2005年1月-2008年12月对43例CML患者进行allo-HSCT,采用白消安加环磷酰胺联合氟达拉滨、阿糖胞苷(Bu/Cy/Flu/Ara-C)为预处理方案,具体剂量为Bu3.2mg·kg-1·d-1静点(iv)或4mg·kg-1·d-1口服(po)2～4d、Cy50mg·kg-1·d-1×2、Flu30mg·m-2·d-1×3、Ara-C2g·m-2·d-1×3。移植方式为HLA相合或半相合亲缘供者造血干细胞移植,其中外周血干细胞移植(PBSCT)16例,骨髓移植(BMT)26例,骨髓加外周血干细胞移植1例。结果:所有患者均获造血重建,发生Ⅱ～Ⅳ度急性移植物抗宿主病(aGVHD)12例(27.9%),慢性GVHD(cGVHD)19例(45.2%),移植相关死亡(TRM)9例(20.9%),细胞遗传学或血液学复发6例(14.0%),其中4例复发后采用格列卫与DLI联合的挽救治疗获得稳定的分子生物学缓解;总体无病生存率(DFS)为(72.0±7.0)%,其中CP1和非CP1期移植患者D...     

Neoplastic meningitis in patients with acute myeloid leukemia scheduled for allogeneic hematopoietic stem cell transplantation

We analyzed the frequency of neoplastic meningitis in patients with acute myeloid leukemia prior to allogeneic hematopoietic stem cell transplantation at our institution. Between 1996 and 2009, cerebrospinal fluid samples of 204 adult patients were examined during pre-transplant work-up for cell counts and, if abnormal, morphologically. We found blasts in cerebrospinal fluid samples of 17 patients with either persistent (n=9) or newly diagnosed (n=8) neoplastic meningitis. All patients proceeded to transplant. The proportion of patients with central nervous system involvement was significantly higher in patients with refractory disease at the time of transplantation compared with patients responding to prior systemic therapy (19% vs. 4.6%; P=0.003). Since most of the patients with central nervous system involvement were asymptomatic, cerebrospinal fluid evaluation should be considered at least in patients with refractory acute myeloid leukemia.     

Molecular and biologic characterization and drug sensitivity of pan-histone deacetylase inhibitor-resistant acute myeloid leukemia cells

Hydroxamic acid analog pan-histone deacetylase (HDAC) inhibitors (HA-HDIs) have shown preclinical and clinical activity against human acute leukemia. Here we describe HA-HDI-resistant human acute myeloid leukemia (AML) HL-60 (HL-60/LR) cells that are resistant to LAQ824, vorinostat, LBH589, and sodium butyrate. HL-60/LR cells show increased expression of HDACs 1, 2, and 4 but lack HDAC6 expression, with concomitant hyperacetylation of heat shock protein 90 (hsp90). Treatment with HA-HDI failed to further augment hsp90 acetylation, or increase the levels of p21 or reactive oxygen species (ROSs), in HL-60/LR versus HL-60 cells. Although cross-resistant to antileukemia agents (eg, cytarabine, etoposide, and TRAIL), HL-60/LR cells are collaterally sensitive to the hsp90 inhibitor 17-AAG. Treatment with 17-AAG did not induce hsp70 or deplete the hsp90 client proteins AKT and c-Raf. HL-60/LR versus HL-60 cells display a higher growth fraction and shorter doubling time, along with a shorter interval to generation of leukemia and survival in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Thus, resistance of AML cells to HA-HDIs is associated with loss of HDAC6, hyperacetylation of hsp90, aggressive leukemia phenotype, and collateral sensitivity to 17-AAG. These findings suggest that an hsp90 inhibitor-based antileukemia therapy may override de novo or acquired resistance of AML cells to HA-HDIs.     

Flow cytometric quantification and immunophenotyping of leukemic stem cells in acute myeloid leukemia

Leukemic stem cells (LSCs) are root of clonal growth in acute myeloid leukemia (AML) and responsible for the propagation of leukemic blasts (LBs). LSCs are considered as CD34?+?CD38- population among LBs and often express as CD123, CD44, or CD184, which are rarely expressed on normal hematopoietic stem cells and could be the potential therapeutic targets. Using multi-color flow cytometry, we analyzed the proportions of CD34?+?CD38- LSCs and expression of CD123, CD44, and CD184 on LSCs in 63 patients with AML. The median proportion of LSCs was 1.3?% (0.0-33.1?%) at the time of diagnosis. Of all patients, 74.6?% of them had CD123-positive LSCs, all patients had CD44-positive LSCs, and 85.7?% had CD184-positive LSCs, respectively. The proportions of LSCs were significantly lower in the complete remission (CR) group compared with non-CR group (P?=?0.006). The lower proportions of LSCs in CR group indicated that measurement of the proportion of LSCs might be helpful to predict the prognosis of AML.