Expression,regulation and function of phosphofructo-kinase/fructose-biphosphatases (PFKFBs) in glucocorticoid-induced apoptosis of acute lymphoblastic leukemia cells

Background  

Glucocorticoids (GCs) cause apoptosis and cell cycle arrest in lymphoid cells and constitute a central component in the therapy of lymphoid malignancies, most notably childhood acute lymphoblastic leukemia (ALL). PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-2), a kinase controlling glucose metabolism, was identified by us previously as a GC response gene in expression profiling analyses performed in children with ALL during initial systemic GC mono-therapy. Since deregulation of glucose metabolism has been implicated in apoptosis induction, this gene and its relatives, PFKFB1, 3, and 4, were further analyzed.     

Prognostic relevance of dic(9;20)(p11;q13) in childhood B‐cell precursor acute lymphoblastic leukaemia treated with Berlin‐Frankfurt‐Münster (BFM) protocols containing an intensive induction and post‐induction consolidation therapy

The presence of a dicentric chromosome dic(9;20) has been reported to have an unfavourable prognosis in children with B‐cell precursor acute lymphoblastic leukaemia (BCP‐ALL). As outcome may be influenced by type and composition of treatment, we analyzed 19 BCP‐ALL patients with dic(9;20) who have been treated with ALL‐BFM (Berlin‐Frankfurt‐Münster) protocols that included a 4‐drug induction and subsequent consolidation therapy. All patients were good responders to prednisone and in complete remission after induction therapy. Eight patients had no molecular disease after induction and another eight patients had levels ≤10^?4 after consolidation therapy. After a median follow‐up of 3·4 years, probabilities of 5‐year event‐free and overall survival were 75 ± 11% and 94 ± 6%, respectively. Of note, there was a tendency for extramedullary disease in case of relapse (two of three relapses with central nervous system involvement). In conclusion, in the context of ALL‐BFM protocols dic(9;20)‐positivity appeared to have a favourable prognosis, which could be due to a dose‐ and time‐intensified induction and induction consolidation therapy. Given that in vitro studies have shown high cellular sensitivity of dic(9;20)‐positive leukemic blasts to l ‐asparaginase and cytarabine, it is reasonable to speculate that both drugs, as given early during BFM‐like induction and consolidation therapy, may have contributed to this good outcome.     

Efficacy of rhesus antibodies (anti-Rh0 (D)) in autoimmune thrombocytopenia: Correlation with response to high dose IgG and the degree of haemolysis

Summary We have compared the efficacy of high-dose IgG with that of Rhesus antibodies (anti-Rh₀ (D)) in 5 patients with autoimmune thrombocytopenic purpura (3 adults and 2 children). Although only transient, high-dose IgG (0.4 g/kg×5 days) was effective in all patients (peak values 50–200×10⁹/l), whereas anti-Rh₀(D) (11–20 g/kg×5 days) led to comparable results in only 3 patients (165×10⁹/l, 72×10⁹/l, 33×10⁹/l). This response to anti-Rh₀ (D) was neither related to the degree of induced haemolysis (increase of LDH and decrease of haptoglobin) nor to the amount of IgG antibodies bound to red blood cells, as quantified by the 125-I-antiglobulin test. A decrease of platelet-associated IgG was recorded in 3 patients: 2 of them showed an improvement of platelet counts and in one of them there was no response.We conclude that the therapeutic response of high-dose IgG and anti-Rh₀ (D) is independent of the degree of induced haemolysis and may not be predicted from the effectiveness of either therapy alone.     

Detection of minimal residual disease identifies differences in treatment response between T-ALL and precursor B-ALL

We performed sensitive polymerase chain reaction-based minimal residual disease (MRD) analyses on bone marrow samples at 9 follow-up time points in 71 children with T-lineage acute lymphoblastic leukemia (T-ALL) and compared the results with the precursor B-lineage ALL (B-ALL) results (n = 210) of our previous study. At the first 5 follow-up time points, the frequency of MRD-positive patients and the MRD levels were higher in T-ALL than in precursor-B-ALL, reflecting the more frequent occurrence of resistant disease in T-ALL. Subsequently, patients were classified according to their MRD level at time point 1 (TP1), taken at the end of induction treatment (5 weeks), and at TP2 just before the start of consolidation treatment (3 months). Patients were considered at low risk if TP1 and TP2 were MRD negative and at high risk if MRD levels at TP1 and TP2 were 10(-3) or higher; remaining patients were considered at intermediate risk. The relative distribution of patients with T-ALL (n = 43) over the MRD-based risk groups differed significantly from that of precursor B-ALL (n = 109). Twenty-three percent of patients with T-ALL and 46% of patients with precursor B-ALL were classified in the low-risk group (P =.01) and had a 5-year relapse-free survival (RFS) rate of 98% or greater. In contrast, 28% of patients with T-ALL were classified in the MRD-based high-risk group compared to only 11% of patients with precursor B-ALL (P =.02), and the RFS rates were 0% and 25%, respectively (P =.03). Not only was the distribution of patients with T-ALL different over the MRD-based risk groups, the prognostic value of MRD levels at TP1 and TP2 was higher in T-ALL (larger RFS gradient), and consistently higher RFS rates were found for MRD-negative T-ALL patients at the first 5 follow-up time points.     

ETV6/RUNX1-positive relapses evolve from an ancestral clone and frequently acquire deletions of genes implicated in glucocorticoid signaling

Approximately 25% of childhood acute lymphoblastic leukemias carry the ETV6/RUNX1 fusion gene. Despite their excellent initial treatment response, up to 20% of patients relapse. To gain insight into the relapse mechanisms, we analyzed single nucleotide polymorphism arrays for DNA copy number aberrations (CNAs) in 18 matched diagnosis and relapse leukemias. CNAs were more abundant at relapse than at diagnosis (mean 12.5 vs 7.5 per case; P=.01) with 5.3 shared on average. Their patterns revealed a direct clonal relationship with exclusively new aberrations at relapse in only 21.4%, whereas 78.6% shared a common ancestor and subsequently acquired distinct CNA. Moreover, we identified recurrent, mainly nonoverlapping deletions associated with glucocorticoid-mediated apoptosis targeting the Bcl2 modifying factor (BMF) (n=3), glucocorticoid receptor NR3C1 (n=4), and components of the mismatch repair pathways (n=3). Fluorescence in situ hybridization screening of additional 24 relapsed and 72 nonrelapsed ETV6/RUNX1-positive cases demonstrated that BMF deletions were significantly more common in relapse cases (16.6% vs 2.8%; P=.02). Unlike BMF deletions, which were always already present at diagnosis, NR3C1 and mismatch repair aberrations prevailed at relapse. They were all associated with leukemias, which poorly responded to treatment. These findings implicate glucocorticoid-associated drug resistance in ETV6/RUNX1-positive relapse pathogenesis and therefore might help to guide future therapies.     

Acute hemolysis and liver cirrhosis as leading symptoms of Wilson's disease in childhood

Acute hemolytic anemia and the development of liver cirrhosis with ascites 3 month thereafter suggested Wilson's disease in a 12 years old child, which was confirmed by inappropriate copper metabolism. In addition, neurological symptoms and renal tubular insufficiency characterized the early stage of the disease.     

Cooperative studies in the treatment of acute lymphoblastic leukemia in children in Austria--report of 10 years' experience

437 children with acute lymphoblastic leukaemia (ALL) have been treated at 9 different institutions in Austria utilizing common protocols and central registration between 1974 and 1984. 227 patients (132 boys and 95 girls, group I) were treated between 1974 and 1980 using 3 consecutive protocols (KMK, O 76, A 78), which were essentially derived from the Memphis studies VII and VIII. Patients with a high risk of relapse were treated according to the LSA 2-L2 protocol. 210 patients (112 boys and 98 girls, group II) were consecutively treated following the BFM protocols 76/79 and 81/83. In this group, treatment intensity was adjusted to the initially determined individual risk of relapse (BFM risk score or risk factor). To date, the life table analysis demonstrates that the probability of continuous complete remission for patients in group II is 60% after 5 and 3 years (BFM 76/79 and BFM 81/83, respectively), whereas group I reaches a level of 37.3%. The prognostic difference between risk and non-risk patients in both studies of group II was eliminated. Despite a higher morbidity and non-leukaemia-related mortality in group II, the therapeutic success can be attributed to the intensification of induction therapy.     

RNAi-mediated silencing of TEL/AML1 reveals a heat-shock protein- and survivin-dependent mechanism for survival

The TEL/AML1 fusion gene results from the most frequent t(12;21)(p13;q22) translocation in childhood acute lymphoblastic leukemia (ALL). Its contribution to transformation is largely unknown, in particular with respect to survival and apoptosis. We therefore silenced TEL/AML1 expression in leukemic REH cells by RNA inhibition, which eventually led to programmed cell death. Microarray and 2D gel electrophoresis data demonstrated a differential regulation of heat-shock proteins (HSPs), among them HSP90, as well as of its client, survivin. Consistent with these findings, ectopic expression of TEL/AML1 in Ba/F3 cells increased protein levels of HSP90 and survivin and conferred resistance to apoptotic stimuli. Our data suggest that TEL/AML1 not only contributes to leukemogenesis by affecting an antiapoptotic network but also seems to be indispensable for maintaining the malignant phenotype. The functional relationship between TEL/AML1, HSP90, and survivin provides the rational for targeted therapy, be it the fusion gene or the latter 2 proteins.