Neutrophils Kill Antibody-Opsonized Cancer Cells by Trogoptosis

Destruction of cancer cells by therapeutic antibodies occurs, at least in part, through antibody-dependent cellular cytotoxicity (ADCC), and this can be mediated by various Fc-receptor-expressing immune cells, including neutrophils. However, the mechanism(s) by which neutrophils kill antibody-opsonized cancer cells has not been established. Here, we demonstrate that neutrophils can exert a mode of destruction of cancer cells, which involves antibody-mediated trogocytosis by neutrophils. Intimately associated with this is an active mechanical disruption of the cancer cell plasma membrane, leading to a lytic (i.e., necrotic) type of cancer cell death. Furthermore, this mode of destruction of antibody-opsonized cancer cells by neutrophils is potentiated by CD47-SIRPα checkpoint blockade. Collectively, these findings show that neutrophil ADCC toward cancer cells occurs by a mechanism of cytotoxicity called trogoptosis, which can be further improved by targeting CD47-SIRPα interactions.

Desmopressin testing in haemo-philia A patients and carriers

Introduction: Desmopressin (DDAVP) testing (DT) in patients (pts) with haemophilia A (HA) and carriers (CHA) is up to now not standardized. This prompted us to evaluate results of DT carried out between 1996 and 2011 in centres of the Competence Network Haemor-rhagic Diatheses East. Patients and method: An increase of the factor VIII activity (FVIII) above 50% or at least the two fold of initial values within 120 min after DDAVP was defined as complete response (CR). Data from 80 patients (31 children, 49 adults) of whom 64 suffered from HA (sub-HA: n = 48; mild: n = 14; moderate: n = 2) and 16 patients CHA were evaluated. Results: In 34 patients DDAVP was given i. v. (dose range: 0.26–0.6 μg/kg body weight, mean: 0.33), in 31 intranasally (i.n. 300–600 μg) and in 15 s. c. (15–40 μg). The maximal FVIII increase was reached 60 min after DDAVP. For i. v. application the mean FVIII increase was 3.1-fold, for i. n. 2.1-fold and for s. c. 2.4-fold. A CR was de tected in 71 patients, a non-response in 9. Mild side effects such as flush, headaches or nausea were observed in 11 patients (14%). Conclusion: For desmopressin testing in patients with haemophilia A and carriers i. v. application at 0.3 μg/kg body weight and the determination of FVIII before and 60 min after desmopressin infusion is recommended.

[Varicella Vaccination Coverage and Possible Factors Influencing Parental Vaccination Decisions in Munich Area 2009-2011 after Introduction of Routine Varicella Vaccination]

Background and Objective: Germany introduced routine varicella vaccination for all infants aged 11-14 months in 2004; since 2009, a second dose was recommended for toddlers aged 15-23 months. In Bavaria, vaccination with combined MMRV vaccine has been routinely reimbursed since the introduction of the 2-dose vaccination schedule. We investigated varicella vaccination coverage and factors associated with parental acceptance of varicella vaccination in the area of Munich from 2009 to 2011, within the frame of the 'Bavarian Varicella Surveillance Project' (2006-2011). Method: Annual cross-sectional parent survey of random samples of 600 children aged 18-36 months in Munich on the child's vaccination status for varicella and measles, socio-demographic data and parental attitude towards varicella vaccination. Results: During 2009-2011, the first dose varicella vaccination (VV) coverage increased from 53% (2009) to 68% (2011) while the second dose VV increased from 29% (2009) to 59% (2011). First-dose measles vaccination coverage was 88-91% (2009-2011). In 2009, 51% of all vaccinated children received the combined MMRV vaccine as first dose; in 2011, 94% (p<0.001). In 2009, 27% of all parents considered varicella vaccination as superfluous. This percentage had decreased to 15% by 2011. Recommendation of varicella vaccination by the physician was the most important explanatory factor and was significantly associated with parental acceptance of varicella vaccination in 2009 to 2011 (adjusted OR 11.5; 95%CI 3.6-36.3 (2009), 26.7; 95%CI 5.4-132.2 (2010) and 12.7; 95%CI 3.9-41.4 (2011)). Conclusions: From 2009 to 2011, first dose VV coverage further increased by approximately 15% up to 68%, corresponding with the increased use of MMRV. Although parental acceptance had increased, first dose coverage for varicella was still considerably lower than coverage for measles in 2011. Physician's recommendation of VV was the only independent factor significantly associated with parental acceptance in all study years. A further increase in varicella vaccination coverage is necessary in order to avoid potential negative effects such as an increase in the mean age of children getting infected with varicella. Therefore, information campaigns for both parents and physicians are urgently needed.

EZH2 mutation in an adolescent with Weaver syndrome developing acute myeloid leukemia and secondary hemophagocytic lymphohistiocytosis

Weaver syndrome is an overgrowth syndrome characterized by pre- and postnatal overgrowth with distinctive craniofacial appearance. Mutations in the enhancer of zeste homolog 2 (EZH2) gene were found to cause Weaver syndrome, and have been associated with hematologic malignancies, including acute myeloid leukemia (AML). We present the first report of a patient with Weaver syndrome, who developed AML and harbored an EZH2 mutation. The clinical course of the 16-year-old female adolescent patient was complicated by a secondary hemophagocytic lymphohistiocytosis. Genomic DNA was isolated from bone marrow cells at AML diagnosis. Polymerase chain reactions were performed with primers covering all exons of the EZH2 gene. We found a novel heterozygous EZH2 mutation within exon 5 that caused an amino acid change from proline to leucine at position 132 (p.Pro132Leu) within the catalytic D1 domain. Analysis of a remission sample also showed this mutation, indicating a germline mutation. It remains to be elucidated whether EZH2 mutations contribute to disease severity in specific AML cases.

Minimal residual disease analysis by eight-color flow cytometry in relapsed childhood acute lymphoblastic leukemia

Multiparametric flow cytometry is an alternative approach to the polymerase chain reaction method for evaluating minimal residual disease in treatment protocols for primary acute lymphoblastic leukemia. Given considerable differences between primary and relapsed acute lymphoblastic leukemia treatment regimens, flow cytometric assessment of minimal residual disease in relapsed leukemia requires an independent comprehensive investigation. In the present study we addressed evaluation of minimal residual disease by flow cytometry in the clinical trial for childhood relapsed acute lymphoblastic leukemia using eight-color flow cytometry. The major challenge of the study was to reliably identify low amounts of residual leukemic cells against the complex background of regeneration, characteristic of follow-up samples during relapse treatment. In a prospective study of 263 follow-up bone marrow samples from 122 patients with B-cell precursor acute lymphoblastic leukemia, we tested various B-cell markers, adapted the antibody panel to the treatment protocol, and evaluated its performance by a blinded parallel comparison with the polymerase chain reaction data. The resulting eight-color single-tube panel showed a consistently high overall concordance (P<0.001) and, under optimal conditions, sensitivity similar to that of the reference polymerase chain reaction method. Overall, evaluation of minimal residual disease by flow cytometry can be successfully integrated into the clinical management of relapsed childhood acute lymphoblastic leukemia either as complementary to the polymerase chain reaction or as an independent risk stratification tool. ALL-REZ BFM 2002 clinical trial information: NCT00114348.

β2 integrin mediates hantavirus-induced release of neutrophil extracellular traps

β2 Integrin–mediated systemic release of neutrophil extracellular traps is a novel mechanism of immunopathology associated with hantavirus infection.

Rodent-borne hantaviruses are emerging human pathogens that cause severe human disease. The underlying mechanisms are not well understood, as hantaviruses replicate in endothelial and epithelial cells without causing any cytopathic effect. We demonstrate that hantaviruses strongly stimulated neutrophils to release neutrophil extracellular traps (NETs). Hantavirus infection induced high systemic levels of circulating NETs in patients and this systemic NET overflow was accompanied by production of autoantibodies to nuclear antigens. Analysis of the responsible mechanism using neutrophils from β2 null mice identified β2 integrin receptors as a master switch for NET induction. Further experiments suggested that β2 integrin receptors such as complement receptor 3 (CR3) and 4 (CR4) may act as novel hantavirus entry receptors. Using adenoviruses, we confirmed that viral interaction with β2 integrin induced strong NET formation. Collectively, β2 integrin–mediated systemic NET overflow is a novel viral mechanism of immunopathology that may be responsible for characteristic aspects of hantavirus-associated disease such as kidney and lung damage.

Copy number genome alterations are associated with treatment response and outcome in relapsed childhood ETV6/RUNX1-positive acute lymphoblastic leukemia

The clinical heterogeneity among first relapses of childhood ETV6/RUNX1-positive acute lymphoblastic leukemia indicates that further genetic alterations in leukemic cells might affect the course of salvage therapy and be of prognostic relevance. To assess the incidence and prognostic relevance of additional copy number alterations at relapse of the disease, we performed whole genome array comparative genomic hybridization of leukemic cell DNA from 51 patients with first ETV6/RUNX1-positive relapse enrolled in and treated according to the relapse trials ALL-REZ of the Berlin-Frankfurt-Münster Study Group. Within this cohort of patients with relapsed ETV6/RUNX1-positive acute lymphoblastic leukemia, the largest analyzed for genome wide DNA copy number alterations to date, alterations were present in every ETV6/RUNX1-positive relapse and a high proportion of them occurred in recurrent overlapping chromosomal regions. Recurrent losses affected chromosomal regions 12p13, 6q21, 15q15.1, 9p21, 3p21, 5q and 3p14.2, whereas gains occurred in regions 21q22 and 12p. Loss of 12p13 including CDKN1B was associated with a shorter remission duration (P=0.009) and a lower probability of event-free survival (P=0.001). Distribution of X-chromosomal copy number alterations was gender-specific: whole X-chromosome loss occurred exclusively in females, gain of Xq only in males. Loss of the glucocorticoid receptor gene NR3C1 (5q31.3) was associated with a poor response to induction treatment (P=0.003), possibly accounting for the adverse prognosis of some of the ETV6/RUNX1-positive relapses.

[Health Promotion for Long-Term Unemployed Persons]

A controlled trial to improve perceived health in a sample of long-term unemployed persons was conducted. As primary endpoint the SF12-questionnaire was used. The intervention was tailored to the specific needs of the long-term unemployed combining individual sessions based on motivational interviewing and group sessions designed with the participation of the participants. 365 participants were enrolled in the study. 287 or, respectively, 148 unemployed persons participated at the 3-months/12-months follow-up assessments. A positive effect of the intervention in the setting of long-term unemployed persons has been shown for perceived health, mental health and changes towards more physical activity and healthier nutrition.

Synergistic activity of bortezomib and HDACi in preclinical models of B-cell precursor acute lymphoblastic leukemia via modulation of p53, PI3K/AKT, and NF-κB

PURPOSE

Relapse of disease and subsequent resistance to established therapies remains a major challenge in the treatment of childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). New therapeutic options, such as proteasome and histone deacetylase inhibitors (HDACi) with a toxicity profile differing from that of conventional cytotoxic agents, are needed for these extensively pretreated patients.

EXPERIMENTAL DESIGN

Antiproliferative and proapoptotic effects of combined HDACi/proteasome inhibitor treatments were analyzed using BCP-ALL monocultures, cocultures with primary mesenchymal stroma cells from patients with ALL, and xenograft mouse models. The underlying molecular mechanisms associated with combined treatment were determined by gene expression profiling and protein validation.

RESULTS

We identified the proteasome inhibitor bortezomib as a promising combination partner for HDACi due to the substantial synergistic antileukemic activity in BCP-ALL cells after concomitant application. This effect was maintained or even increased in the presence of chemotherapeutic agents. The synergistic effect of combined HDACi/BTZ treatment was associated with the regulation of genes involved in cell cycle, JUN/MAPK, PI3K/AKT, p53, ubiquitin/proteasome, and NF-κB pathways. We observed an activation of NF-κB after bortezomib treatment and the induction of apoptosis-related NF-κB target genes such as TNFαRs after concomitant treatment, indicating a possible involvement of NF-κB as proapoptotic mediator. In this context, significantly lower NF-κB subunits gene expression was detected in leukemia cells from patients who developed a relapse during frontline chemotherapy, compared with those who relapsed after cessation of frontline therapy.

CONCLUSION

These results provide a rationale for the integration of HDACi/BTZ combinations into current childhood BCP-ALL treatment protocols.

Minimal residual disease after induction is the strongest predictor of prognosis in intermediate risk relapsed acute lymphoblastic leukaemia - long-term results of trial ALL-REZ BFM P95/96

PURPOSE

This blinded prospective study was performed to optimise the risk assessment of children with a late isolated, combined or an early combined bone marrow (BM) relapse of precursor B-cell acute lymphoblastic leukaemia (ALL). The aim was to develop a reliable tool to identify patients with an intermediate risk relapse who are in need of haematopoietic stem cell transplantation (HSCT).

METHODS

Included were 80 children and adolescents with first intermediate risk BM relapse of ALL recruited in trial ALL-REZ BFM P95/96. We assessed the prognostic value of minimal residual disease (MRD) after induction therapy quantified by PCR using leukaemia clone-specific T-cell receptor/immunoglobulin gene rearrangements.

RESULTS

Molecular good responders (MRD < 10(-3), n=46) had a probability of event-free survival (pEFS) at 10 years of 76% standard error (SE) ± 6% and a cumulative incidence of second relapse (CIR) at 10 years of 21% SE ± 6%; pEFS of molecular poor responders (MRD ≥ 10(-3), n=34) at 10 years was 18% SE ± 7% and CIR 61% SE ± 9% (p<0.001). Cox regression analysis revealed MRD after induction to be the strongest independent prognostic parameter with a 6.6-fold increased risk (95% confidence interval 3.3-13.5, p<0.001) for molecular poor responders to suffer a subsequent adverse event compared to good responders.

CONCLUSION

In patients with intermediate risk BM relapse of ALL, low MRD after induction is associated with an excellent long-term prognosis with conventional chemo-/radiotherapy whereas patients with insufficient response have an extremely poor prognosis. Therefore, in the subsequent trial ALL-REZ BFM 2002, MRD is used to allocate molecular good responders to conventional post-induction therapy and molecular poor responders to allogeneic HSCT.

Evaluation of the prognostic meaning of C-reactive protein (CRP) in children and adolescents with classical Hodgkin's lymphoma (HL)

BACKGROUND

In adult cancer patients the negative predictive value of elevated CRP levels has been described for several malignancies. Only few studies have analyzed the prognostic role of CRP in children and adolescents with classical HL. In these studies elevated CRP levels correlate with the presence of classical risk factors and adverse outcome.

PATIENTS AND METHODS

The prognostic role of CRP for patients with classical HL admitted to the GPOH-HD-2002 study was analyzed retrospectively.

RESULTS

CRP levels were documented for 369 of 573 patients. Significant (p<0.05) increased median CRP levels were found in the presence of B-Symptoms (25.7 vs. 5.1 mg/l), extranodal involvement (21.5 vs. 7.5 mg/l), elevated erythrocyte sedimentation rate (ESR, 13.0 vs. 1.0 mg/l) and stage III/IV disease (15.5 vs. 5.3 mg/l). 83.9% of patients with elevated and 45.8% of patients with normal CRP had an ESR >30 mm/h.

CONCLUSION

Elevated CRP levels were associated with classical risk factors of HL. CRP and ESR may reflect different biological processes. CRP was prognostic within early stage TG-1 patients treated with reduced treatment, but not within advanced stage TG-2+3.

Antiproliferative Properties of the Serotonin Receptor Antagonist Ondansetron Correlate with Increased Nitric Oxides Release and Inducible Nitric Oxide Synthase Activity in the Acute Lymphoblastic Leukemia Cell Line REH

A recent report from our group described that the (serotonin receptor-3)-antagonist ondansetron exhibits antiproliferative effects in the B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cell line REH. Furthermore, after each application of ondansetron to cultured REH cells, significant increases (+23%) in the concentration of nitric oxides (NO) were observed in the cell supernatants after 72 hours incubation in standard conditions, and this effect was found to correlate with the described antiproliferative activity. This feature was further confirmed by using mRNA dot blot hybridizations with a specific gene probe for the inducible NO-synthase (iNOS), yielding significant increases (+100%) of iNOS mRNA, which were found to widely correlate with the detected increases of NO release, and also with the previously described antiproliferative effects. The presented results are the first report on high specific pro-inflammatory features of a (serotonin receptor 3)-antagonist in a BCP-ALL cell line, which are associated with previously described antiproliferative properties.

[Health promotion for long-term unemployed. Effects on motivation for a healthy lifestyle]

Among the long-term unemployed ill health is often a hindrance to successful reintegration in the job market. In a quasi-experimental controlled study we examined the effects of a health promotion intervention program tailored to the specific needs of the long-term unemployed combining individual sessions based on motivational interviewing and participatory group sessions including physical activity. Over a period of 3 months the participants of the intervention group (n = 179) showed more improvement compared to the control group (n = 108) in terms of motivation for lifestyle changes towards more physical activity and healthier nutrition. Participants of the intervention group developed an intention to act significantly more often (active lifestyle: odds ratio 4.44; 95% CI: 2.00-9.83; healthy nutrition: odds ratio 3.94; 95% CI: 1.55-10.00) and actually implemented a behavior change significantly more often (active lifestyle: odds ratio 2.77; 95% CI: 1.35-5.71; healthy nutrition: odds ratio 4.34; 95% CI: 1.92-9.78). In terms of smoking and alcohol consumption no significant intervention effects were detected. The results of the study show the effectiveness of the described health promotion program regarding a lifestyle change towards more healthy nutrition and more physical activity.

Randomized controlled trial of taurolidine citrate versus heparin as catheter lock solution in paediatric patients with haematological malignancies

BACKGROUND

A catheter lock solution containing 1.35% taurolidine and 4% citrate could potentially disrupt bacterial surface adherence and consecutive biofilm production due to the anti-adherence properties of taurolidine and the anticlotting and chelator activities of both compounds.

AIM

To compare the impact on microbial catheter colonization and infectious complications of heparin and taurolidine citrate as central venous catheter (CVC) lock solutions in paediatric patients with haematological malignancies.

METHODS

Seventy-one patients aged 1.4-18 years were randomized to two treatment groups using either heparin (N = 36) or taurolidine citrate (N = 35). Infectious complications and clinical side-effects were prospectively monitored and microbial colonization of catheters was assessed at the time of removal.

FINDINGS

There were two bloodstream infections in the taurolidine citrate group versus nine in the heparin group (0.3 vs 1.3 infections per 1000 catheter-days; P = 0.03). Fever of unknown origin and catheter occlusions were observed with a similar frequency in both groups. Microbial colonization was found in 25.4% catheters. The time of no-lock use, but not the type of lock solution or time of observation, was a significant predictor of catheter colonization (P = 0.004). Colonization was not observed in CVCs used immediately with taurolidine citrate lock. Seven patients in the taurolidine citrate group (20%) experienced side-effects (nausea, vomiting, abnormal taste sensations).

CONCLUSION

The use of taurolidine citrate lock solution was associated with a significant reduction in bloodstream infection in immunocompromised paediatric patients. Taurolidine citrate may prevent colonization of CVCs if used from the time of insertion, but not after a period of no-lock catheter use.

High VLA-4 expression is associated with adverse outcome and distinct gene expression changes in childhood B-cell precursor acute lymphoblastic leukemia at first relapse

BACKGROUND

Resistance to therapy and subsequent relapse remain major challenges in the clinical management of relapsed childhood acute lymphoblastic leukemia. As the bone marrow environment plays an important role in survival and chemotherapy resistance of leukemia cells by activating different signaling pathways, such as the VLA-4 and PI3K/Akt pathways, we studied the prognostic and biological impact of VLA-4 expression in leukemia cells from children with relapsed B-cell precursor acute lymphoblastic leukemia and its influence on the sensitivity of the leukemia cells to drugs.

DESIGN AND METHODS

VLA-4 expression was quantified by real-time polymerase chain reaction in leukemia cells from 56 patients with relapsed acute lymphoblastic leukemia enrolled in the ALL-REZ BFM 2002 trial of the Berlin-Frankfurt-Münster study group. Gene expression changes related to VLA-4 expression were investigated by microarray-based mRNA profiling. The effect of VLA-4 signaling on proliferation and drug resistance was studied in co-cultures of leukemia and stromal cells.

RESULTS

High expression of VLA-4 at first relapse was associated with adverse prognostic factors, poor molecular response to therapy and significantly worse probabilities of event-free and overall survival. VLA-4 expression was an independent prognostic parameter. Comparing gene expression profiles of leukemia cells with high versus low VLA-4 expression, we identified 27 differentially expressed genes primarily involved in the PI3K/Akt, ephrin and Rho GTPase pathways. Blocking of VLA-4 signaling in combination with cytarabine treatment abolished the growth supportive effect of stromal cells.

CONCLUSIONS

Our results show that high VLA-4 expression is a marker of poor prognosis and a potential therapeutic target in children with relapsed acute lymphoblastic leukemia and confirm that cellular interactions and biological effects related to VLA-4 play a decisive role in the survival of leukemia cells and response to therapy. (ClinicalTrials.gov identifier: NCT00114348).

Mutations and deletions of the TP53 gene predict nonresponse to treatment and poor outcome in first relapse of childhood acute lymphoblastic leukemia

PURPOSE

In the clinical management of children with relapsed acute lymphoblastic leukemia (ALL), treatment resistance remains a major challenge. Alterations of the TP53 gene are frequently associated with resistance to chemotherapy, but their significance in relapsed childhood ALL has remained controversial because of small studies.

PATIENTS AND METHODS

Therefore, we systematically studied 265 first-relapse patients enrolled in the German Acute Lymphoblastic Leukemia Relapse Berlin-Frankfurt-Mü nster 2002 (ALL-REZ BFM 2002) trial for sequence and copy number alterations of the TP53 gene by using direct sequencing and multiplex ligation-dependent probe amplification.

RESULTS

We observed copy number and sequence alterations of TP53 in 12.4% (27 of 218) of patients with B-cell precursor ALL and 6.4% (three of 47) of patients with T-cell ALL relapse. Backtracking to initial ALL in 23 matched samples revealed that 54% of all TP53 alterations were gained at relapse. Within B-cell precursor ALL, TP53 alterations were consistently associated with nonresponse to chemotherapy (P < .001) and poor event-free survival (P < .001) and overall survival rates (P = .002). TP53 alterations also had a significant impact on survival within intermediate-risk (S2) and high-risk (S3/S4) relapse patients (P = .007 and P = .019, respectively). This prognostic significance of TP53 alterations was confirmed in multivariate analysis. Besides their clinical impact, TP53 alterations were associated with a higher fraction of leukemic cells in S/G(2)-M phase of the cell cycle at relapse diagnosis.

CONCLUSION

Alterations of the TP53 gene are of particular importance in the relapse stage of childhood ALL, in which they independently predict high risk of treatment failure in a significant number of patients. Therefore, they will aid in future risk assessment of children with ALL relapse.

Outcome of children and adolescents with relapsed acute lymphoblastic leukaemia and non-response to salvage protocol therapy: a retrospective analysis of the ALL-REZ BFM Study Group

AIM OF THE STUDY

Non-response (NR) to treatment of childhood relapsed acute lymphoblastic leukaemia (ALL) is an end-point of protocol therapy. Subsequent management has not yet been standardised. This study analyses different approaches after NR to aid optimising future strategies.

PATIENTS AND METHODS

Ninety-three children with NR to treatment according to ALL relapse-protocols of the Berlin/Frankfurt/Muenster (BFM) Study Group (03/1990-2006/1999) were retrospectively assigned to a curative (C: intensive polychemotherapies, stem cell transplantation (SCT); n=51), palliative (P: 1-2 antineoplastic agents; n=23) or supportive (S: no antineoplastic therapy; n=19) treatment approach.

RESULTS

Median survival after diagnosis of NR were 121 (C), 89 (P) and 42 (S) days, respectively (p<0.001). In cohort C, a complete remission (2ndCR) was obtained in 16/51 patients, among these 13 only after SCT, and nine children achieved partial remission. Ten of the 51 patients died from treatment-related complications, 39/51 from disease progression. Today, two patients are still in continuous CR after SCT. Adverse prognostic factors were overrepresented in the non-curative cohorts. Time-point of relapse and treatment after NR were independent predictors of survival duration. Most patients without antineoplastic treatment died at home, the majority of the others in the hospital.

CONCLUSIONS

Treatment after NR has been heterogeneous and customised. Therapies with curative intent are capable of inducing 2ndCR but associated with high treatment-related morbidity, -mortality and minimal survival. NR patients may, therefore, be ideal candidates for controlled phase I/II trials, thus offering them a chance to benefit from new drugs and promoting drug development for cohorts with better prognosis.

The RNA-binding protein RBM3 is required for cell proliferation and protects against serum deprivation-induced cell death

Hypoxia and other adverse conditions are commonly encountered by rapidly growing cells. The RNA-binding protein RBM3 (RNA-binding motif protein 3), which is transcriptionally induced by low temperature and hypoxia, has recently been implicated in survival of colon cancer cells by mechanisms involving cyclooxygenase-2 (COX-2) signaling. Immunohistochemically, we found strong RBM3 expression in a variety of malignant and proliferating tissues but low expression in resting and terminally differentiated cells. RBM3 expression in fibroblasts and human embryonal kidney (HEK293) cells subjected to serum deprivation or contact inhibition closely paralleled proliferation rates, assessed by real-time RT-PCR and immunoblotting. siRNA-mediated RBM3 knockdown reduced cell viability and finally led to cell death, which did not involve caspase-3-mediated apoptosis, cell cycle arrest, or COX-2 regulation. In contrast, RBM3 over-expression rescued cells from death under serum starvation. This was associated with increased translation rates, as measured by C serine and H phenylalanine incorporation. Together, RBM3 is a critical factor providing cellular survival advantages in an adverse microenvironment presumably by restoring translation efficacy.

Interphase FISH on TEL/AML1 positive acute lymphoblastic leukemia relapses--analysis of clinical relevance of additional TEL and AML1 copy number changes

OBJECTIVES

TEL/AML1 (ETV6/RUNX1) fusion resulting from the translocation t(12;21)(p13;q22) constitutes the most common chimeric fusion gene in initial childhood B-cell precursor (BCP) acute lymphoblastic leukemia (ALL) (19-27%) and has been associated with good prognosis. Three secondary aberrations in TEL/AML1 positive ALL have been suspected to negatively influence outcome: deletion of the second TEL allele (T), gain of the second AML1 allele (A) and duplication of the derivative chromosome 21 (der(21), TA). Many studies have explored such aberrations in initial disease, while only few reports have investigated them in relapses.

METHODS

In this study, bone marrow samples from 38 children with relapsed TEL/AML1 RT-PCR positive and negative BCP-ALL were analyzed for these mutations by interphase fluorescence in situ hybridization and results were compared with published data.

RESULTS

In children with TEL/AML1 positive ALL relapse, additional (a) TEL loss, (b) combined AML1 and der(21) gain, (c) combined TEL loss and AML1 gain as well as (d) the occurrence of a subpopulation with the signal pattern 1T/3A/1TA appear to be related to higher peripheral blast counts (PBCs) at relapse diagnosis (a and d) or a tendency towards the occurrence of a subsequent relapse (b and c) (P-values <0.05).

CONCLUSIONS

Our data together with published results on TEL/AML1 positive ALL suggest that frequencies of additional TEL and AML1 mutations are, with the exception of loss of untranslocated TEL, higher in first relapses than in initial disease. They also show that it is important to consider combined mutations in the analysis of this leukemia entity.

Submicroscopic bone marrow involvement in isolated extramedullary relapses in childhood acute lymphoblastic leukemia: a more precise definition of “isolated” and its possible clinical implications, a collaborative study of the Resistant Disease Committee of the International BFM study group

This study investigates the extent of bone marrow (BM) involvement at diagnosis of apparent isolated extramedullary (AIEM) relapses of childhood acute lymphoblastic leukemia (ALL) and its relation to prognosis. Sixty-four children with first AIEM relapse treated in Germany, Czech Republic, or France were included. Real-time quantitative polymerase chain reaction using T-cell receptor and immunoglobulin gene rearrangements provided a sensitive measure of submicroscopic BM involvement, which was detectable at a level of 10−4 or higher in 46 patients and less than 10−4 in 11 patients, and was nondetectable (sensitivity: 10−4) in 7 patients. In the total cohort, the probability of event-free survival (pEFS) for children with BM involvement of 10−4 or higher was 0.30 (0.09 ± SE) versus 0.60 (± 0.12) for those with less than 10−4 (P = .13). The cumulative incidence of subsequent relapse was 0.24 (± 0.01) for patients with BM involvement less than 10−4 and 0.65 (± 0.01) for those with 10−4 or higher (P = .012). Restricted to central nervous system (CNS) relapses, pEFS was 0.11 (± 0.09) for patients with BM involvement 10−4 or higher and 0.63 (± 0.17) for those with less than 10−4 (P = .053). CNS relapses were associated with a higher (≥ 10−4: 80%) submicroscopic BM involvement than testicular relapses (≥ 10−4: 57%, P = .08). In summary, we show marked heterogeneity of submicroscopic BM involvement at first AIEM relapse diagnosis in children with ALL, and demonstrate its possible prognostic relevance.

Response to subcutaneous therapy with mistletoe in recurrent multisystem Langerhans cell histiocytosis

We report a case of histologically proven multisystem (MS) Langerhans cell histiocytosis (LCH) with recurrent disease reactivations after systemic chemotherapy. Through the use of subcutaneous therapy with mistletoe (MT), an inactive disease state was achieved.

Gene expression shift towards normal B cells, decreased proliferative capacity and distinct surface receptors characterize leukemic blasts persisting during induction therapy in childhood acute lymphoblastic leukemia

In childhood acute lymphoblastic leukemia (ALL), persistence of leukemic blasts during therapy is of crucial prognostic significance. In the present study, we address molecular and cell biologic features of blasts persisting after 1 week of induction glucocorticoid therapy. Genome-wide gene expression analysis of leukemic samples from precursor B-cell ALL patients (n=18) identified a set of genes differentially expressed in blasts at diagnosis day 0 (d0) and persisting on day 8 (d8). Expression changes indicate a shift towards mature B cells, inhibition of cell cycling and increased expression of adhesion (CD11b/ITGAM) and cytokine (CD119/IFNGR1) receptors. A direct comparison with normal B cells, which are largely therapy resistant, confirmed the differentiation shift at the mRNA (n=10) and protein (n=109) levels. Flow cytometric analysis in independent cohorts of patients confirmed both a decreased proliferative activity (n=13) and the upregulation of CD11b and CD119 (n=29) in d8 blasts. The differentiation shift and low proliferative activity in d8 blasts may account for the persistence of blasts during therapy and affect their sensitivity to further therapeutic treatment. CD11b and CD119 are potential specific markers for d8 blast persistence and detection of minimal residual disease, which warrant further investigation.

Natural history and early diagnosis of LAD-1/variant syndrome

The syndrome of leukocyte adhesion deficiency (LAD) combined with a severe Glanzmann-type bleeding disorder has been recognized as a separate disease entity. The variability in clinical and cell biological terms has remained largely unclear. We present data on 9 cases from 7 unrelated families, with 3 patients being actively followed for more than 12 years. The disease entity, designated LAD-1/variant syndrome, presents early in life and consists of nonpussing infections from bacterial and fungal origin, as well as a severe bleeding tendency. This is compatible with 2 major blood cell types contributing to the clinical symptoms (ie, granulocytes and platelets). In granulocytes of the patients, we found adhesion and chemotaxis defects, as well as a defect in NADPH oxidase activity triggered by unopsonized zymosan. This last test can be used as a screening test for the syndrome. Many proteins and genes involved in adhesion and signaling, including small GTPases such as Rap1 and Rap2 as well as the major Rap activity-regulating molecules, were normally present. Moreover, Rap1 activation was intact in patients' blood cells. Defining the primary defect awaits genetic linkage analysis, which may be greatly helped by a more precise understanding and awareness of the disease combined with the early identification of affected patients.

Genetic investigations of Saethre–Chotzen syndrome presenting with renal cell carcinoma

Saethre-Chotzen syndrome (SCS) is a craniosynostosis syndrome characterized by facial and limb abnormalities caused by mutations in the TWIST1 gene on 7p21, resulting in variable loss of function. The transcription factor TWIST1 has also been shown to promote tumor growth and has been linked to the formation of metastases in breast cancers. One suggestive case of inherited SCS and malignancy in childhood has been reported previously. Here, we present immunological and genetic investigations including the determination of a new stop codon mutation in the TWIST1 gene in SCS associated with malignancy in childhood.

The Thalidomide Analogue, CC-4047, Induces Apoptosis Signaling and Growth Arrest in Childhood Acute Lymphoblastic Leukemia Cells In vitro and In vivo

PURPOSE

Thalidomide and its analogues have shown promise in the treatment of multiple myeloma but their therapeutic potential has not been evaluated in models of acute lymphoblastic leukemia (ALL).

EXPERIMENTAL DESIGN

We assessed the effects of the thalidomide analogue, CC-4047, on the growth and apoptosis signaling of human B cell precursor (BCP) ALL cell lines and freshly obtained childhood BCP-ALL cells grown with or without stromal cells. In addition, we studied the effects of CC-4047 on the progression and dissemination of xenotransplanted human BCP-ALL cells in nonobese diabetic/severe combined immunodeficiency mice.

RESULTS

CC-4047 reduced the proliferation of human BCP-ALL cell lines in vitro. In contrast with the antileukemic effect of cytarabin, this was more pronounced when cell lines or freshly obtained childhood BCP-ALL cells were cocultured with stromal cells. CC-4047 induced the cleavage of caspase-3, caspase-9, and poly(ADP-ribose) polymerase in stroma-cocultured BCP-ALL cells. The inhibition of tumor growth, caspase-3 cleavage, and reduced microvessel density was observed in nonobese diabetic/severe combined immunodeficiency mice inoculated s.c. with childhood BCP-ALL cells upon CC-4047 treatment. After i.v. BCP-ALL xenotransplantation, CC-4047 reduced splenic dissemination.

CONCLUSIONS

The thalidomide analogue, CC-4047, displays profound cytostatic effects on stroma-supported human ALL cells both in vitro and in vivo.

Brief communication: stability and catalytic activity of novel circular DNAzymes

DNAzymes represent a new generation of catalytic nucleic acids for specific RNA targeting in order to inhibit protein translation from the specifically cleaved mRNA. The 10-23 DNAzyme was found to hydrolyze RNA in a sequence-specific manner both in vitro and in vivo. Although single-stranded DNAzymes may represent the most effective nucleic acid drug to date, they are nevertheless sensitive to nuclease degradation and require modifications for in vivo application. However, previously used stabilization of DNAzymes by site-specific phosphorothioate (PT) modifications reduces the catalytic activity, and the PTO displays toxic side effects when applied in vivo. Thus, improving the stability of DNAzymes without reducing their catalytic activity is essential if the potential of these compounds should be realized in vivo.

RESULTS

The Circozyme was tested targeting the mRNA of the most common genetic rearrangement in pediatric acute lymphoblastic leukemia TEL/AML1 (ETV6/RUNX1). The Circozyme exhibits a stability comparable to PTO-modified DNAzymes without reduction of catalytic activity and specificity and may represent a promising tool for DNAzyme in vivo applications.

CONCLUSION

The inclusion of the catalytic site and the specific mRNA binding sequence of the DNAzyme into a circular loop-stem-loop structure (Circozyme) of approximately 70 bases presented here represents a new effective possibility of DNAzyme stabilization.