Ana Silvia G. Lima

Adhesion molecules and differentiation syndrome: phenotypic and functional analysis of the effect of ATRA, As2O3, phenylbutyrate, and G-CSF in acute promyelocytic leukemia

Background and Objectives Differentiation Syndrome (DS) is a treatment complication which can occur in patients treated with acute promyelocytic leukemia (APL) with all transretinoic acid (ATRA) or As2O3, and is characterized by enhanced leukocyte transmigration. As2O3, Phenylbutyrate (PB) and G-CSF are known to potentiate ATRA effects. Our aim was to analyze the changes in expression and function of adhesion molecules induced by ATRA, As2O3, G-CSF and PB, and their association. Design and Methods APL blasts and NB4 cells were treated with ATRA, As2O3, PB, G-CSF or their association and the expression of adhesion molecules was determined by flow cytometry. Cell adhesion was evaluated in vitro using Matrigel and for the in vivo analysis, Balb-c mice were injected with NB4 cells pre-treated with ATRA, As2O3, ATRA+G-CSF or ATRA+As2O3. In addition, CD54 and CD18 knock-out mice were injected with NB4 cells and concomitantly treated with ATRA. In both models, the MPO activity in the lungs was determined 6 hours after the injection of the cells. Results In NB4 and APL blasts, ATRA and As2O3 increased CD54 expression, but no synergism was detected. CD11b and CD18 were also up-regulated by ATRA in primary cells. PB and G-CSF had no effect, but the latter potentiated ATRA-induced CD18 up-regulation. These changes were accompanied by increased adhesion to Matrigel and to lung microvasculature, and reversed by anti-CD54, anti-CD18 antibodies. In CD54 and CD18 knock-out mice the ATRA effect was canceled. Interpretation and Conclusions The use of As2O3, PB and G-CSF in association with ATRA should not aggravate DS 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 (TGFβ) signaling, leading to cell growth advantage. Halofuginone (HF), a low-molecular-weight alkaloid that modulates TGFβ 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 TGFβ 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 TGFβ target genes involved in cell cycle regulation (TGFB, TGFBRI, SMAD3, p15, and p21) and down-regulation of MYC. Additionally, TGFβ protein levels were decreased in leukemic TG animals and HF in vivo could restore TGFβ 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 TGFβ blockade in APL. Since loss of the TGFβ response in leukemic cells may be an important second oncogenic hit, modulation of TGFβ signaling may be of therapeutic interest.

The association of ICAM-1 Exon 6 (E469K) but not of ICAM-1 Exon 4 (G241R) and PECAM-1 Exon 3 (L125V) polymorphisms with the development of differentiation syndrome in acute promyelocytic leukemia.

The use of all trans‐retinoic acid (ATRA) is the basis of treatment of acute promyelocytic leukemia (APL) and represents the paradigm of differentiation therapy. In general, ATRA is well‐tolerated but may be associated with a potentially lethal side‐effect, referred to as retinoic acid or differentiation syndrome (DS). The cellular and molecular mechanisms of DS are poorly understood and involve changes in the adhesive qualities and cytokine secretion of leukemic cells during ATRA‐induced differentiation. As leukocyte extravasation is a key event in DS pathogenesis, we analyzed the association between the polymorphisms at Exon 4 (G241R) and Exon 6 (E469K) of ICAM‐1 and Exon 3 (L125V) of PECAM‐1 genes with DS development in APL patients treated with ATRA and anthracyclines. DS was diagnosed in 23/127 (18.1%) APL patients at an average of 11.5 days after the start of ATRA. All patients presented respiratory distress associated with increased ground‐glass opacity in chest radiographies. Other accompanying symptoms were: fever not attributable to infection (65.2%), generalized edema (37.5%), weight gain (37.5%), and impairment of renal function (8.6%). We detected an association between development of DS and the AA genotype at Codon 469 of ICAM‐1 (odds ratio of 3.5; 95% confidence interval: 1.2–10.2). Conversely, no significant association was detected between G241R or L125V polymorphisms at Exon 4 of ICAM‐1 and Exon 3 of PECAM‐1, respectively. Our results suggest that susceptibility to DS in APL patients may be influenced by genetic variation in adhesion molecule loci.

The co-expression of PML/RAR alpha and AML1/ETO fusion genes is associated with ATRA resistance

patients are routinely monitored by measuring their serum immunoglobulin and urine light chains – a logical step would be to supplement, or replace, the urine assays with serum FLC measurements, as has already happened in many centres. Thus, the conclusion of Tate et al (2005) that larger prospective studies are needed before FLC measurement is ‘routinely applied to the monitoring of patients with IIMM’, is a generalization, drawn outside the context of the data they have presented. Serial FLC measurement is being undertaken in all patients in the current Medical Research Council Myeloma IX Study, which should provide further information on patients treated in a systematic way. Future studies may investigate clinical benefit further, perhaps with modification or change in treatment determined by FLC measurement.

The expression of ΔNTP73, 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 ΔNp73, which have little transcriptional activity and exert dominant‐negative function towards TP53 and TAp73. We compared TATP73 and ΔNTP73 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 ΔNTP73 expression was detected in non‐RGA cases. TP53 expression did not vary according to ΔNTP73/TATP73 expression ratio. Leukaemic cells with higher ΔNTP73/TATP73 ratios were significantly more resistant to cytarabine‐induced apoptosis.

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

OBJETIVO: A leucemia promielocitica aguda (LPA) apresenta uma boa resposta ao tratamento com o acido all trans retinoico (ATRA). Entretanto, alguns pacientes desenvolvem uma complicacao grave chamada sindrome do acido retinoico (SAR). O objetivo deste estudo foi comparar as caracteristicas hematologicas e imunofenotipicas de pacientes com LPA que desenvolveram a SAR com as daqueles que nao a desenvolveram. METODOS: Foram analisados retrospectivamente os prontuarios, exames radiologicos, lâminas de esfregaco de sangue e medula ossea de 71 pacientes com LPA, dos quais a analise imunofenotipica havia sido realizada em 56 casos. Foram identificados oito casos de SAR que, do ponto de vista clinico, caracterizaram-se por insuficiencia respiratoria (n=8), insuficiencia renal (n=2), febre (n=5), ganho ponderal (n=3), edema periferico (n=3) e derrame pleural (n=5). As seguintes variaveis foram comparadas entre pacientes com e sem SAR: dosagem de hemoglobina, contagens de leucocitos e plaquetas no sangue periferico, distribuicao dos subtipos hipergranular e variante, percentagens de blastos CD33+, CD13+, CD117+ na medula ossea, intensidade e variacao dos valores de fluorescencia destes antigenos nas celulas leucemicas, expressas atraves dos canais medianos (CMFs) e dos coeficientes de variacao (CVs) de fluorescencia, respectivamente. RESULTADOS: A incidencia da SAR foi de 11,26% e o tempo medio para seu desenvolvimento 11,5 dias do inicio do tratamento. Todos os pacientes apresentaram desconforto respiratorio agudo, por vezes associado a febre, ganho de peso, edema e insuficiencia renal. Os achados radiologicos mais comuns foram: opacidades em vidro fosco, derrame pleural, espessamento peribronquico e aumento da trama vascular pulmonar. Nenhuma das variaveis 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 incidencia e as caracteristicas da SAR neste grupo de pacientes brasileiros foi semelhante a descrita na literatura. Nenhum dos parâmetros estudados correlacionou-se significativamente a um maior risco de desenvolvimento desta complicacao.

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.

Apoptosis induction by (+)α-tocopheryl succinate in the absence or presence of all-trans retinoic acid and arsenic trioxide in NB4, NB4-R2 and primary APL cells

We analyzed the effect of (+)alpha-tocopheryl succinate (alpha-TOS) alone or associated with arsenic trioxide (ATO) or all-trans retinoid acid (ATRA) in acute promyelocytic leukemia (APL). alpha-TOS-induced apoptosis in APL clinical samples and in ATRA-sensitive (NB4) and ATRA-resistant (NB4-R2) APL cell lines. The effective dose 50% (ED-50) was calculated to be 71 and 58muM, for NB4 and NB4-R2, respectively. alpha-TOS neither induced nor modified ATRA-induced differentiation of APL cells, and did not affect the proliferation and differentiation of normal CD34(+) hematopoietic progenitors in methylcellulose assays. alpha-TOS exerted a moderate antagonistic effect to ATO-induced apoptosis when treatment was done simultaneously but when alpha-TOS was added 24h after ATO, an additive effect was observed. Our results support the concept of alpha-TOS as an anti-leukemic compound which spares normal hematopoiesis.

Prognostic impact of KMT2E transcript levels on outcome of patients with acute promyelocytic leukaemia treated with all-trans retinoic acid and anthracycline-based chemotherapy: an International Consortium on Acute Promyelocytic Leukaemia study

The KMT2E (MLL5) gene encodes a histone methyltransferase implicated in the positive control of genes related to haematopoiesis. Its close relationship with retinoic acid–induced granulopoiesis suggests that the deregulated expression of KMT2E might lead acute promyelocytic leukaemia (APL) blasts to become less susceptible to the conventional treatment protocols. Here, we assessed the impact of KMT2E expression on the prognosis of 121 APL patients treated with ATRA and anthracycline‐based chemotherapy. Univariate analysis showed that complete remission (P = 0·006), 2‐year overall survival (OS) (P = 0·005) and 2‐year disease‐free survival (DFS) rates (P = 0·037) were significantly lower in patients with low KMT2E expression; additionally, the 2‐year cumulative incidence of relapse was higher in patients with low KMT2E expression (P = 0·04). Multivariate analysis revealed that low KMT2E expression was independently associated with lower remission rate (odds ratio [OR]: 7·18, 95% confidence interval [CI]: 1·71–30·1; P = 0·007) and shorter OS (hazard ratio [HR]: 0·27, 95% CI: 0·08–0·87; P = 0·029). Evaluated as a continuous variable, KMT2E expression retained association with poor remission rate (OR: 10·3, 95% CI: 2·49–43·2; P = 0·001) and shorter survival (HR: 0·17, 95% IC: 0·05–0·53; P = 0·002), while the association with DFS was of marginal significance (HR: 1·01; 95% CI: 0·99–1·02; P = 0·06). In summary, low KMT2E expression may predict poor outcome in APL patients.

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

BackgroundHalofuginone (HF) is a low-molecular-weight alkaloid that has been demonstrated to interfere with Metalloproteinase-2 (MMP-2) and Tumor Growth Factor-β (TGF-β) 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.MethodsNOD/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.ResultsHF 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-β-signaling.ConclusionTaken together, our results demonstrate that HF inhibits SMAD2 signaling and reduces leukemia growth and angiogenesis.