Halofuginone inhibits phosphorylation of SMAD-2 reducing angiogenesis and leukemia burden in an acute promyelocytic leukemia mouse model.

BACKGROUND: Halofuginone (HF) is a low-molecular-weight alkaloid that has been demonstrated to interfere with Metalloproteinase-2 (MMP-2) and Tumor Growth Factor-ß (TGF-ß) function and, to present antiangiogenic, antiproliferative and proapoptotic properties in several solid tumor models. Based on the fact that high levels of Vascular Endothelial Growth Factor (VEGF) and increased angiogenesis have been described in acute myeloid leukemia and associated with disease progression, we studied the in vivo effects of HF using an Acute Promyelocytic Leukemia (APL) mouse model. METHODS: NOD/SCID mice were transplanted with leukemic cells from hCG-PML/RARA transgenic mice (TM) and treated with HF 150 µg/kg/day for 21 days. The leukemic infiltration and the percentage of VEGF+ cells were evaluated by morphology and flow cytometry. The effect of HF on the gene expression of several pro- and antiangiogenic factors, phosphorylation of SMAD2 and VEGF secretion was assessed in vitro using NB4 and HUVEC cells. RESULTS: HF treatment resulted in hematological remission with decreased accumulation of immature cell and lower amounts of VEGF in BM of leukemic mice. In vitro, HF modulated gene expression of several pro- and antiangiogenic factors, reduced VEGF secretion and phosphorylation of SMAD2, blocking TGF-ß-signaling. CONCLUSION: Taken together, our results demonstrate that HF inhibits SMAD2 signaling and reduces leukemia growth and angiogenesis.

Methionine-induced hyperhomocysteinemia reverts fibrinolytic pathway activation in a murine model of acute promyelocytic leukemia.

Increased fibrinolysis is an important component of acute promyelocytic leukemia (APL) bleeding diathesis. APL blasts overexpress annexin II (ANXII), a receptor for tissue plasminogen activator (tPA), and plasminogen, thereby increasing plasmin generation. Previous studies suggested that ANXII plays a pivotal role in APL coagulopathy. ANXII binding to tPA can be inhibited by homocysteine and hyperhomocysteinemia can be induced by L-methionine supplementation. In the present study, we used an APL mouse model to study ANXII function and the effects of hyperhomocysteinemia in vivo. Leukemic cells expressed higher ANXII and tPA plasma levels (11.95 ng/mL in leukemic vs 10.74 ng/mL in wild-type; P = .004). In leukemic mice, administration of L-methionine significantly increased homocysteine levels (49.0 µmol/mL and < 6.0 µmol/mL in the treated and nontreated groups, respectively) and reduced tPA levels to baseline concentrations. The latter were also decreased after infusion of the LCKLSL peptide, a competitor for the ANXII tPA-binding site (11.07 ng/mL; P = .001). We also expressed and purified the p36 component of ANXII in Pichia methanolica. The infusion of p36 in wild-type mice increased tPA and thrombin-antithrombin levels, and the latter was reversed by L-methionine administration. The results of the present study demonstrate the relevance of ANXII in vivo and suggest that methionine-induced hyperhomocysteinemia may reverse hyperfibrinolysis in APL.

Halofuginone has anti-proliferative effects in acute promyelocytic leukemia by modulating the transforming growth factor beta signaling pathway.

Promyelocytic leukemia-retinoic acid receptor alpha (PML-RARα) expression in acute promyelocytic leukemia (APL) impairs transforming growth factor beta (TGFß) signaling, leading to cell growth advantage. Halofuginone (HF), a low-molecular-weight alkaloid that modulates TGFß signaling, was used to treat APL cell lines and non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice subjected to transplantation with leukemic cells from human chorionic gonadotrophin-PML-RARα transgenic mice (TG). Cell cycle analysis using incorporated bromodeoxyuridine and 7-amino-actinomycin D showed that, in NB4 and NB4-R2 APL cell lines, HF inhibited cellular proliferation (P<0.001) and induced apoptosis (P = 0.002) after a 24-hour incubation. Addition of TGFß revealed that NB4 cells were resistant to its growth-suppressive effects and that HF induced these effects in the presence or absence of the cytokine. Cell growth inhibition was associated with up-regulation of TGFß target genes involved in cell cycle regulation (TGFB, TGFBRI, SMAD3, p15, and p21) and down-regulation of MYC. Additionally, TGFß protein levels were decreased in leukemic TG animals and HF in vivo could restore TGFß values to normal. To test the in vivo anti-leukemic activity of HF, we transplanted NOD/SCID mice with TG leukemic cells and treated them with HF for 21 days. HF induced partial hematological remission in the peripheral blood, bone marrow, and spleen. Together, these results suggest that HF has anti-proliferative and anti-leukemic effects by reversing the TGFß blockade in APL. Since loss of the TGFß response in leukemic cells may be an important second oncogenic hit, modulation of TGFß signaling may be of therapeutic interest.

Antibody-targeted horseradish peroxidase associated with indole-3-acetic acid induces apoptosis in vitro in hematological malignancies.

Indole-3-acetic acid (IAA), when oxidized by horseradish peroxidase (HRP), is transformed into cytotoxic molecules capable of inducing cell injury. The aim of this study was to test if, by targeting hematopoietic tumors with HRP-conjugated antibodies in association with IAA treatment, there is induction of apoptosis. We used two lineages of hematologic tumors: NB4, derived from acute promyelocytic leukemia (APL) and Granta-519 from mantle cell lymphoma (MCL). We also tested cells from 12 patients with acute myeloid leukemia (AML) and from 10 patients with chronic lymphocytic leukemia (CLL). HRP targeting was performed with anti-CD33 or anti-CD19 antibodies (depending on the origin of the cell), followed by incubation with goat anti-mouse antibody conjugated with HRP. Eight experimental groups were analyzed: control, HRP targeted, HRP targeted and incubated with 1, 5 and 10mM IAA, and cells not HRP targeted but incubated with 1, 5 and 10mM IAA. Apoptosis was analyzed by flow cytometry using annexin V-FITC and propidium iodide labeling. Results showed that apoptosis was dependent on the dose of IAA utilized, the duration of exposure to the prodrug and the origin of the neoplasia. Targeting HRP with antibodies was efficient in activating IAA and inducing apoptosis.

The presence of CD56/CD16 in T-cell acute lymphoblastic leukaemia correlates with the expression of cytotoxic molecules and is associated with worse response to treatment.

Some cases of T-cell acute lymphoblastic leukaemia (ALL) express markers found in natural-killer (NK) cells, such as CD56 and CD16. Out of 84 T-cell ALL cases diagnosed at our Institution, CD56 and/or CD16 was detected in 24 (28.5%), which we designated T/NK-ALL group. Clinical features, laboratory characteristics, survival and expression of cytotoxic molecules were compared in T/NK-ALL and T-ALL patients. Significant differences were observed regarding age (24.9 vs. 16.4 years in T/NK-ALL and T-ALL, respectively, P = 0.006) and platelet counts (177 x 10(9)/l vs. 75 x 10(9)/l in T/NK-ALL and T-ALL, respectively, P = 0.03). Immunophenotypic analysis demonstrated that CD34, CD45RA and CD33 were more expressed in T/NK-ALL patients, whereas CD8 and terminal deoxynucleotidyl transferase were more expressed in T-ALL patients (P < 0.05). The mean overall survival (863 vs. 1869 d, P = 0.02) and disease-free survival (855 vs. 2095 d, P = 0.002) were shorter in patients expressing CD56/CD16. However, multivariate analysis identified CD56/CD16 as an independent prognostic factor only for DFS. Cytotoxic molecules were highly expressed in T/NK-ALL compared to T-ALL. Perforin, granzyme B and TIA-1 were detected in 12/17, 4/17 and 7/24 T/NK-ALL patients and in 1/20, 0/20 and 1/20 T-ALL respectively (P < 0.001, P = 0.036 and P = 0.054). Therefore, the presence of CD56/CD16 was associated with distinct clinical features and expression of cytotoxic molecules in the blasts.

The expression of DeltaNTP73, TATP73 and TP53 genes in acute myeloid leukaemia is associated with recurrent cytogenetic abnormalities and in vitro susceptibility to cytarabine cytotoxicity.

TP73 encodes for two proteins: full-length TAp73 and DeltaNp73, which have little transcriptional activity and exert dominant-negative function towards TP53 and TAp73. We compared TATP73 and DeltaNTP73 expression in acute myeloid leukaemia (AML) samples and normal CD34(+) progenitors. Both forms were more highly expressed in leukaemic cells. Amongst AML blasts, TATP73 was more expressed in AML harbouring the recurrent genetic abnormalities (RGA): PML-RARA, RUNX1-RUNX1T1 and CBFB-MYH11, whereas higher DeltaNTP73 expression was detected in non-RGA cases. TP53 expression did not vary according to DeltaNTP73/TATP73 expression ratio. Leukaemic cells with higher DeltaNTP73/TATP73 ratios were significantly more resistant to cytarabine-induced apoptosis.

Determination of P-glycoprotein, MDR-related protein 1, breast cancer resistance protein, and lung-resistance protein expression in leukemic stem cells of acute myeloid leukemia.

BACKGROUND: The most primitive leukemic precursor in acute myeloid leukemia (AML) is thought to be the leukemic stem cell (LSC), which retains the properties of self-renewal and high proliferative capacity and quiescence of the hematopoietic stem cell. LSC seems to be immunophenotypically distinct and more resistant to chemotherapy than the more committed blasts. Considering that the multidrug resistance (MDR) constitutive expression may be a barrier to therapy in AML, we have investigated whether various MDR transporters were differentially expressed at the protein level by different leukemic subsets. METHODS: The relative expression of the drug-efflux pumps P-gp, MRP, LRP, and BCRP was evaluated by mean fluorescence index (MFI) and the Kolmogorov-Smirnov analysis (D values) in five leukemic subpopulations: CD34+CD38-CD123+ (LSCs), CD34+CD38+CD123-, CD34+CD38+CD123+, CD34+CD38+CD123-, and CD34- mature cells in 26 bone marrow samples of CD34+ AML cases. RESULTS: : The comparison between the two more immature subsets (LSC versus CD34+CD38-CD123- cells) revealed a higher P-gp, MRP, and LRP expression in LSCs. The comparative analysis between LSCs and subsets of intermediate maturation (CD34+CD38+) demonstrated the higher BCRP expression in the LSCs. In addition, P-gp expression was also significantly higher in the LSC compared to CD34+CD38+CD123- subpopulation. Finally, the comparative analysis between LSC and the most mature subset (CD34-) revealed higher MRP and LRP and lower P-gp expression in the LSCs. CONCLUSIONS: Considering the cellular heterogeneity of AML, the higher MDR transporters expression at the most immature, self-renewable, and quiescent LSC population reinforces that MDR is one of the mechanisms responsible for treatment failure.

Flow cytometry characterization of leukemic phase of nasal NK/T-cell lymphoma in tumor biopsies and peripheral blood.

We report the findings of the immunophenotypic profile of three cases of nasal T/NK cell lymphoma in leukemic phase. Flow cytometry analysis was carried out using cell suspensions of tumor nasal biopsies and peripheral blood. Tumor samples were composed by a mixture of a predominant subset of medium-size true NK cytCD3epsilon-, sCD3epsilon-, CD56+ cells mixed with a minor subset of medium-size T/NK sCD3epsilon+, CD56+ cells. Both subsets were also detected in peripheral blood. In addition, an infiltration of small-size sCD3epsilon+, CD56- normal T lymphocytes was also present.

PRAME is a membrane and cytoplasmic protein aberrantly expressed in chronic lymphocytic leukemia and mantle cell lymphoma.

The preferentially expressed antigen in melanoma (PRAME) gene is aberrantly expressed in chronic lymphoproliferative disorders (CLD). We produced and characterized an anti-PRAME monoclonal antibody (MoAb), which was then applied in a quantitative flow cytometric (QFC) method to evaluate PRAME expression in leukemic cells from the peripheral blood (PB) of 47 patients with chronic lymphocytic leukemia and seven with mantle cell lymphoma as well as in the PB mononuclear cells (PBMCs) and B lymphocytes from 15 healthy subjects. Approximately 90% of CLD, but none of the normal samples, presented more than 20% of PRAME+ lymphocytes. Moreover, the intensity of PRAME expression was significantly higher in CLD cells compared to normal B lymphocytes and PBMCs. By immunofluorescence microscopy and by permeabilized flow cytometry we demonstrated that PRAME is a membrane antigen and a cytoplasmic protein aberrantly expressed in malignant CLD. Our results suggest that the analysis of PRAME protein may contribute for the distinction between normal and leukemic cells in CLD, and that PRAME may be a potential target for therapy.

[Hematological features and expression profile of myeloid antigens of acute promyelocytic leukemia patients: analysis of prognostic factors for development of the retinoic acid syndrome]. / Características hematológicas e perfil de expressão de antígenos mielóides de pacientes com leucemia promielocítica aguda: análise de fatores prognósticos para o desenvolvimento da síndrome do ácido retinóico.

BACKGROUND: Acute Promyelocytic Leukemia (APL) is characterized by its good response to treatment with all trans retinoic acid (ATRA). However, some patients receiving ATRA develop a serious complication called retinoid syndrome (RS). The objective of this study was to compare the hematological and immunophenotypic features of APL patients who developed RS with those who did not. METHODS: We reviewed the medical records, roentgenograms, peripheral blood smears and bone marrow aspirates from 71 APL patients. Immunophenotypic analyses were available in 56 of these cases. Eight cases of RS were detected, whose clinical presentation was characterized by respiratory distress (n = 8), impairment of the renal function (n = 2), fever (n = 5), weight gain (n = 3), edema (n = 3) and/or pleural effusion (n = 5). The following variables were compared in patients with and without RS: hemoglobin levels, leukocyte and platelet counts, frequency of hypergranular and variant morphological subtypes, percentages of CD33+, CD13+, CD117+ blasts in the bone marrow, fluorescence intensity and variation of these markers in the leukemic cells, expressed as the median channel of fluorescence (MCF) and fluorescence coefficient of variation (CV), respectively. RESULTS: RS incidence was 11.26% and the average time for syndrome development was 11.5 days after starting ATRA treatment. All patients presented acute respiratory distress. Other symptoms included fever, weight gain, edema and renal insufficiency. The main radiological findings were ground glass opacities, increased vascular pedicle and peribronchial cuffing. There was no significant correlation between the variables selected and the risk of development of RS, however the Odds Ratios for patients presenting MCF for CD117 > 30 ua and CV for CD33 < 50 were of 7.14 (P = 0.08) and 7.86 (P = 0.06), respectively. CONCLUSIONS: The incidence, as well as the clinical, radiological and laboratory features of RS in this group of Brazilian APL patients were similar to those described in literature. None of the variables studied were significantly correlated to a higher risk of developing RS.

Características hematológicas e perfil de expressão de antígenos mielóides de pacientes com leucemia promielocítica aguda: análise de fatores prognósticos para o desenvolvimento da síndrome do ácido retinóico / Hematological features and expression profile of myeloid antigens of acute promyelocytic leukemia patients: analysis of prognostic factors for development of the retinoic acid syndrome

OBJETIVO: A leucemia promielocítica aguda (LPA) apresenta uma boa resposta ao tratamento com o ácido all trans retinóico (ATRA). Entretanto, alguns pacientes desenvolvem uma complicação grave chamada síndrome do ácido retinóico (SAR). O objetivo deste estudo foi comparar as características hematológicas e imunofenotípicas de pacientes com LPA que desenvolveram a SAR com as daqueles que não a desenvolveram. MÉTODOS: Foram analisados retrospectivamente os prontuários, exames radiológicos, lâminas de esfregaço de sangue e medula óssea de 71 pacientes com LPA, dos quais a análise imunofenotípica havia sido realizada em 56 casos. Foram identificados oito casos de SAR que, do ponto de vista clínico, caracterizaram-se por insuficiência respiratória (n=8), insuficiência renal (n=2), febre (n=5), ganho ponderal (n=3), edema periférico (n=3) e derrame pleural (n=5). As seguintes variáveis foram comparadas entre pacientes com e sem SAR: dosagem de hemoglobina, contagens de leucócitos e plaquetas no sangue periférico, distribuição dos subtipos hipergranular e variante, percentagens de blastos CD33+, CD13+, CD117+ na medula óssea, intensidade e variação dos valores de fluorescência destes antígenos nas células leucêmicas, expressas através dos canais medianos (CMFs) e dos coeficientes de variação (CVs) de fluorescência, respectivamente. RESULTADOS: A incidência da SAR foi de 11,26 por cento e o tempo médio para seu desenvolvimento 11,5 dias do início do tratamento. Todos os pacientes apresentaram desconforto respiratório agudo, por vezes associado à febre, ganho de peso, edema e insuficiência renal. Os achados radiológicos mais comuns foram: opacidades em vidro fosco, derrame pleural, espessamento peribrônquico e aumento da trama vascular pulmonar. Nenhuma das variáveis laboratoriais analisadas correlacionou-se significativamente ao risco de desenvolvimento da SAR, entretanto as Odd Ratios para CMF para o CD117 > 30 ua e CV para o CD33 < 50 foram de 7,14 (P=0,08) e de 7,86 (P=0,06), respectivamente. CONCLUSAO: A incidência e as características da SAR neste grupo de pacientes brasileiros foi semelhante à descrita na literatura. Nenhum dos parâmetros estudados correlacionou-se significativamente a um maior risco de desenvolvimento desta complicação.

Increased lymphocyte death by neglect-apoptosis is associated with lymphopenia and autoantibodies in lupus patients presenting with neuropsychiatric manifestations.

To evaluate lymphocyte death by neglect-apoptosis features in systemic lupus erythematosus (SLE) patients presenting with neuropsychiatric (NPSLE) involvement we studied 40 SLE patients with active disease, 20 with and 20 without neuropsychiatric manifestations, and 20 control individuals. Lymphocyte apoptosis was evaluated by means of DNA staining using flow cytometry, immediately after cell isolation and after incubation with culture medium or autologous serum. Compared with controls, NPSLE and non-NPSLE patients exhibited increased rates of neglect-apoptosis immediately after cell isolation. Only NPSLE patients exhibited an increased neglect-apoptosis rate after incubation with culture medium; however, the neglect-apoptosis rate was associated with lymphopenia in both series of patients. After lymphocyte incubation with autologous serum, only NPSLE patients exhibited a significant negative correlation between the neglect-apoptosis rate and the number of peripheral lymphocytes. The incubation of lymphocytes with autologous serum containing antiphospholipid or anti-SSA/Ro antibodies significantly increased the neglect-apoptosis in NPSLE when compared with non-NPSLE patients with a similar autoantibody profile. In conclusion, NPSLE and non-NPSLE patients shared several abnormalities in terms of lymphocyte neglect-apoptosis. Peculiar findings were observed in NPSLE patients particularly after incubation with autologous serum, such as the fact that the increased lymphocyte death by neglect-apoptosis was associated with lymphopenia and with the presence of antiphospholipid and anti-SSA/Ro antibodies.

Expression of CD117 and CD11b in bone marrow can differentiate acute promyelocytic leukemia from recovering benign myeloid proliferation.

The morphologic characteristics of bone marrow aspirates from patients recovering from acute agranulocytosis may be closely similar to the pattern observed in cases of acute promyelocytic leukemia (APL). The clinical manifestation also can be ambiguous in a substantial number of cases. The immunophenotypic features of bone marrow from 5 patients recovering from acute agranulocytosis, showing an increase in the percentage of promyelocytes (26%-66%), were compared with the immunophenotype of 31 consecutive patients with APL whose diagnosis was confirmed by PML-RAR alpha gene rearrangement. All markers were similarly expressed, except for CD117 and CD11b. CD117 was positive in 24 (77%) of the APL cases and in none of the acute agranulocytosis cases. On the other hand, CD11b was positive in 5 (100%) of the acute agranulocytosis cases and in only 2 (6%) of the APL cases. Thus, the CD117-CD11b+ phenotype was detected in all patients recovering from agranulocytosis and in only 1 (3%) of 31 APL cases. Therefore, we suggest that the combination of both markers is helpful in the differentiation of APL from recovering benign myeloid proliferation.

Reduced function of the multidrug resistance P-glycoprotein in CD34+ cells of patients with aplastic anaemia.

Drug exposure is implicated in the aetiology of some cases of acquired aplastic anaemia (AA), but the reason for this susceptibility remains unclear. We previously demonstrated that P-glycoprotein (P-gp) function, a drug efflux pump, is decreased in AA lymphocytes. To further evaluate whether P-gp activity is also abnormal in AA stem cells, we examined bone marrow (BM) CD34+ cells from newly diagnosed AA patients (AA-d, n = 25), after immunosuppression (AA-IST, n = 13) and after BM transplantation (AA-BMT, n = 8). Of the AA patients with autologous haematopoiesis (AA-d + AA-IST), 15 had drug-induced AA. Thirty-two BM donors were studied as controls. P-glycoprotein function was assessed by the rhodamine 123-efflux assay. P-glycoprotein function in CD34+ cells was reduced in AA-d patients (17.8%, 0-67.7) compared with controls (42.5%, 13.4-57.4; P < 0.001), as well as in AA-IST (20.3%, 1.2-32.0; P < 0.001), but not in AA-BMT (40.9%, 19.0-55.9). P-gp function was reduced more in drug-induced AA (14.5%, 0-27.4) than in the other cases (26.1%, 0-67.7; P = 0.04), but it did not correlate with disease severity. These results indicate that P-gp function is defective in AA CD34+ cells, pointing to a role of P-gp in increased cell susceptibility to xenobiotics in AA.

Blastic CD4 NK cell leukemia/lymphoma: a distinct clinical entity.

We report the findings of three new cases of a distinct clinicopathologic natural killer (NK) cell malignancy characterized by cutaneous, nodal and bone marrow infiltration by CD3-CD4+CD56+ NK blastic cells. Tumor cells were detected in bone marrow and in peripheral blood smears and showed finely distributed nuclear chromatin with nucleoli and a moderate amount of cytoplasm. Epstein-Barr virus (EBV) DNA was negative in the two tested cases. The immunophenotypes determined by flow cytometry were identical concerning mCD3-cytCD3-CD4+weakCD56+ HLA-DR+. The TCR was in germline configuration in the two cases tested. NK cell activity was demonstrated only in one out of the two cases tested. The negative reactions with alpha-naphthyl-acetate-esterase (ANAE), CD11b and CD14 strongly suggested that the tumor cells were not of the monocytic lineage.

Influence of functional MDR1 gene polymorphisms on P-glycoprotein activity in CD34+ hematopoietic stem cells.

BACKGROUND AND OBJECTIVES: Expression of the multidrug resistance P-glycoprotein, a transmembrane drug transporter, is influenced by recently described polymorphisms of the human MDR1 gene. Hematopoietic cells, such as lymphocytes, and hematopoietic stem cells, express P-glycoprotein, but the effect of MDR1 gene polymorphisms on P-glycoprotein activity in stem cells is unknown. We investigated whether T-129C, G26677T and C3435T polymorphisms influence P-glycoprotein function in stem cells. DESIGN AND METHODS: P-glycoprotein function was evaluated in immunomagnetically purified bone marrow CD34+ cells from 33 healthy bone marrow donors by the flow cytometric rhodamine 123-efflux assay. For T-129C and C3435T, bone marrow donors were genotyped by polymerase chain reaction amplification followed by MspA1I and DpnII digestion analyses, respectively. For the analysis of C2677T, exon 21 was sequenced. RESULTS: P-glycoprotein function was not different among the C3435T genotypes (CC, 38.2 +/- 3.5%; n=17; CT, 42.2 +/- 3.3%; n=11; and TT, 45.0 +/- 5.3%; n=5) nor was it among the C2677T genotypes (CC, 39.4 +/- 2.4%; n=27; CT, 43.7 +/- 6.4%; n=5; and TT, 54.3%; n=1). Among the 33 subjects, three were heterozygotes for the 129C allele (CT) and no mutant homozygote was identified. P-glycoprotein was similar in heterozygotes (TC, 50.6 +/- 2.9%) and wild-type subjects (TT, 39.5 +/- 2.4%). INTERPRETATION AND CONCLUSIONS: These findings suggest that the known functional MDR1 gene polymorphisms are not major determinants of P-glycoprotein function in hematopoietic stem cells. Other genetic variants might influence P-glycoprotein activity in this cell type.