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Glucocorticoid (GC) resistance in childhood relapsed B-cell acute lymphoblastic leukemia (B-ALL) represents an important challenge. Despite decades of clinical use, the mechanisms underlying resistance remain poorly understood. Here, we report that in B-ALL, GC paradoxically induce their own resistance by activating a phospholipase C (PLC)-mediated cell survival pathway through the chemokine receptor, CXCR4. We identify PLC as aberrantly activated in GC-resistant B-ALL and its inhibition is able to induce cell death by compromising several transcriptional programs. Mechanistically, dexamethasone (Dex) provokes CXCR4 signaling, resulting in the activation of PLC-dependent Ca2+ and protein kinase C signaling pathways, which curtail anticancer activity. Treatment with a CXCR4 antagonist or a PLC inhibitor improves survival of Dex-treated NSG mice in vivo. CXCR4/PLC axis inhibition significantly reverses Dex resistance in B-ALL cell lines (in vitro and in vivo) and cells from Dex resistant ALL patients. Our study identifies how activation of the PLC signalosome in B-ALL by Dex limits the upfront efficacy of this chemotherapeutic agent. Resistance to glucocorticoids (GC) is a major obstacle for the treatment of pediatric B-cell acute lymphoblastic leukemia (B-ALL). Here, the authors report that GC-triggered CXCR4 internalization promotes a phospholipase C (PLC)-mediated cell survival pathway, driving GC resistance in B-ALL. [ABSTRACT FROM AUTHOR]

Simple Summary: Although remarkable progress in the treatment of acute lymphoblastic leukemia (ALL) has been observed, some patients (~20%) relapse. Resistance to therapies is a hallmark of relapses and treatment failure in ALL. Such resistances may involve different cellular mechanisms, including the modulation by therapeutic drugs of cell survival signaling pathways that may lead to therapy-induced resistance. This article will begin by providing an update of mechanisms of resistance that may lead to therapy-induced resistance in ALL. It also provides proof of concept for the therapeutic exploitation of these signaling pathways to improve treatments. Known as a key effector in relapse of acute lymphoblastic leukemia (ALL), resistance to drug-induced apoptosis, is tightly considered one of the main prognostic factors for the disease. ALL cells are constantly developing cellular strategies to survive and resist therapeutic drugs. Glucocorticoids (GCs) are one of the most important agents used in the treatment of ALL due to their ability to induce cell death. The mechanisms of GC resistance of ALL cells are largely unknown and intense research is currently focused on this topic. Such resistance can involve different cellular and molecular mechanisms, including the modulation of signaling pathways involved in the regulation of proliferation, apoptosis, autophagy, metabolism, epigenetic modifications and tumor suppressors. Recently, several studies point to the paradoxical role of GCs in many survival processes that may lead to therapy-induced resistance in ALL cells, which we called "paradoxical corticosensitivity". In this review, we aim to summarize all findings on cell survival pathways paradoxically activated by GCs with an emphasis on previous and current knowledge on gene expression and signaling pathways. [ABSTRACT FROM AUTHOR]

Three‐dimensional (3D) biomimetic cell culture platforms offer more realistic microenvironments that cells naturally experience in vivo. We developed a tunable hyaluronan‐based hydrogels that could easily be modified to mimic healthy or malignant extracellular matrices (ECMs). For that, we pre‐functionalized our hydrogels with an adhesive polypeptide (poly‐l‐lysine, PLL) or ECM proteins (type III and type IV collagens), naturally present in tumorous tissues, and next, we tuned their stiffness by crosslinking with gradual concentrations of genipin (GnP). Then, we thoroughly characterized our substrates before testing them with glioblastoma and breast cancer cells, and thereafter with endothelial cells. Overall, our hydrogels exhibited (a) increasing stiffness with GnP concentration for every pre‐functionalization and (b) efficient enzyme resistance with PLL treatment, and also with type IV collagen but to a lesser extent. While PLL‐treated hydrogels were not favorable to the culture of any glioblastoma cell lines, they enhanced the proliferation of breast cancer cells in a stiffness‐dependent manner. Contrary to type III collagen, type IV collagen pre‐treated hydrogels supported the proliferation of glioblastoma cells. The as‐desired HA‐based 3D tumor‐like models we developed may provide a useful platform for the study of various cancer cells by simply tuning their biochemical composition and their mechanical properties. [ABSTRACT FROM AUTHOR]

Summary: Congenital sideroblastic anaemia (CSA) is a rare disease caused by germline mutations of genes involved in haem and iron‐sulphur cluster formation, and mitochondrial protein biosynthesis. We performed a retrospective multicentre European study of a cohort of childhood‐onset CSA patients to explore genotype/phenotype correlations. We studied 23 females and 20 males with symptoms of CSA. Among the patients, the most frequently mutated genes were ALAS2 (n = 10; 23·3%) and SLC25A38 (n = 8; 18·6%), causing isolated forms of microcytic anaemia of varying severity. Five patients with SLC19A2 mutations suffered from thiamine‐responsive megaloblastic anaemia and three exhibited the 'anaemia, deafness and diabetes' triad. Three patients with TRNT1 mutations exhibited severe early onset microcytic anaemia associated with thrombocytosis, and two exhibited B‐cell immunodeficiency, inflammatory syndrome and psychomotor delay. The prognoses of patients with TRNT1 and SLC2A38 mutations were generally dismal because of comorbidities or severe iron overload. No molecular diagnosis could be established in 14/43 cases. This study emphasizes the frequency of ALAS2 and SLC25A38 mutations and provides the largest comprehensive analysis to date of genotype/phenotype correlations in CSA. Further studies of CSA patients with data recorded in an international registry would be helpful to improve patient management and establish standardized guidelines. [ABSTRACT FROM AUTHOR]

ABSTRACT The lack of relevant in vitro models for adipose tissue makes necessary the development of a more physiological environment providing spatial and chemical cues for the effective maturation of adipocytes. We developed a biofunctionalized hydrogel with components of adipose extracellular matrix: collagen I, collagen VI, and the cell binding domain of fibronectin and we compared it to usual 2D cultures on plastic plates. This scaffold allowed 3D culture of mature adipocytes from the preadipocytes cell lines 3T3-L1 and 3T3-F442A, as well as primary Human White Preadipocytes (HWP), acquiring in vivo-like organization, with spheroid shaped adipocytes forming multicellular aggregates. The size of these aggregates increased with time up to 120 μm in diameter after 4 weeks of maturation, with good viability. Significantly higher lipogenic activity (up to 20-fold at day 28 for HWP cultures) and differentiation rates were also observed compared to 2D. Gene expression analyses highlighted earlier differentiation and complete maturation of 3D HWP compared to 2D, reinforced by the expression of Perilipin protein after 21 days of nutrition. This increase in adipocytes phenotypic and genotypic markers made this scaffold-driven culture as a robust adipose 3D model. Retinoic acid inhibition of lipogenesis in HWP or isoprenalin and caffeine induction of lipolysis performed on mouse 3T3-F442A cells, showed higher doses of molecules than typically used in 2D, underlying the physiologic relevance of this 3D culture system. Biotechnol. Bioeng. 2017;114: 1813-1824. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The risk and clinical significance of cardiac iron overload due to chronic transfusion varies with the underlying disease. Cardiac iron overload shortens the life expectancy of patients with thalassemia, whereas its effect is unclear in those with myelodysplastic syndromes (MDS). In patients with sickle cell anemia (SCA), iron does not seem to deposit quickly in the heart. Our primary objective was to assess through a multicentric study the prevalence of cardiac iron overload, defined as a cardiovascular magnetic resonance T2*<20 ms, in patients with thalassemia, SCA, or MDS. Patient inclusion criteria were an accurate record of erythrocyte concentrates (ECs) received, a transfusion history >8 ECs in the past year, and age older than 6 years. We included from 9 centers 20 patients with thalassemia, 41 with SCA, and 25 with MDS in 2012-2014. Erythrocytapharesis did not consistently prevent iron overload in patients with SCA. Cardiac iron overload was found in 3 (15%) patients with thalassemia, none with SCA, and 4 (16%) with MDS. The liver iron content (LIC) ranged from 10.4 to 15.2 mg/g dry weight, with no significant differences across groups (P = 0.29). Abnormal T2* was not significantly associated with any of the measures of transfusion or chelation. Ferritin levels showed a strong association with LIC. Non-transferrin-bound iron was high in the thalassemia and MDS groups but low in the SCA group (P<0.001). Hepcidin was low in thalassemia, normal in SCA, and markedly elevated in MDS (P<0.001). Two mechanisms may explain that iron deposition largely spares the heart in SCA: the high level of erythropoiesis recycles the iron and the chronic inflammation retains iron within the macrophages. Thalassemia, in contrast, is characterized by inefficient erythropoiesis, unable to handle free iron. Iron accumulation varies widely in MDS syndromes due to the competing influences of abnormal erythropoiesis, excess iron supply, and inflammation. [ABSTRACT FROM AUTHOR]

We combined topographical and chemical surface modifications of Ti-6Al-4V (TA6V) to improve its osteogenic potential. By acid-etching, we first generated topomimetic surface features resembling, in size and roughness, bone cavities left by osteoclasts. Next, we coated these surfaces with biomimetic Layer-by-Layer films (LbL), composed of chondroitin sulfate A and poly- l-lysine that were mechanically tuned after a post-treatment with genipin. The structural impact of each surface processing step was thoroughly inspected. The desired nano/microrough topographies of TA6V were maintained upon LbL deposition. Whereas no significant promotion of adhesion and proliferation of MC3T3-E1 preosteoblasts were detected after independent or combined modifications of the topography and the chemical composition of the substrates, osteogenic maturation was promoted when both surface treatments were combined, as was evidenced by significant long-term matrix mineralization. The results open promising route toward improved osseointegration of titanium-based implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1988-2000, 2016. [ABSTRACT FROM AUTHOR]

We have identified a deletion of 125 bp (α–αΔ125) (NG_000006.1: g.37040_37164del) in the α-globin gene cluster in a Kabyle population. A combination of singlex and multiplex polymerase chain reaction (PCR)-based assays have been used to identify the molecular defect. Sequencing of the abnormal PCR amplification product revealed a novel α1-globin promoter deletion. The endpoints of the deletion were characterized by sequencing the deletion junctions of the mutated allele. The observed deletion was located 378 bp upstream of the α1-globin gene transcription initiation site and leaves the α2 gene intact. In some patients, the α–αΔ125deletion was shown to segregate with Hb S (HBB: c.20A>T) and/or Hb C (HBB: c.19G>A) or a β-thalassemic allele. The α–αΔ125deletion has no discernible effect on red cell indices when inherited with no other abnormal globin genes. The family study demonstrated that the deletion is heritable. This is the only example of an intergenic α2-α1 non coding DNA deletion, leaving the α2-globin gene and the α1 coding part intact. [ABSTRACT FROM PUBLISHER]

Vestibular schwannoma (VS) growth in neurofibromatosis type 2 (NF2) can be responsible for brainstem compression and hearing loss. Surgical removal remains the standard therapy despite potential morbidity. Previous studies suggested that the inhibition of the VEGF-pathway with bevacizumab could result in hearing improvement, reduction of the tumor volume or both in adults. We retrospectively describe the French experience of bevacizumab treatment delivered for progressive VS in pediatric NF2 patients. Patients received Bevacizumab 5 or 10 mg/kg every 2 weeks according to the physician's choice. Follow-up included clinical assessment, audiometry and volumetric MRI every 3-6 months. Seven patients harboring 11 VS were included. The median age at inclusion was 15 years (11.4-18.8), and the median treatment duration was 11.3 months (3.2-55.6). At baseline, the median tumor volume was 1.2 cm (0.52-13.5) and the median word recognition score was 90 % (0-100). We observed one major response, two minor responses and a decrease in the rate of tumor growth for the 4 other patients. The median annual growth rate before treatment was significantly higher than after 1 year of treatment (138 vs. 36 %, n = 5, p = 0.043). We noted one hearing improvement over the course of 1 year under treatment (hearing response rate was 14 %). Overall, the treatment was well tolerated. Our study supports that bevacizumab is an attractive therapeutic option for pediatric NF2 patients with growing VS. Thorough multidisciplinary evaluation is necessary to identify the best candidates prior to treatment. It is likely that a better functional outcome would be expected if targeted therapies were discussed early in the management of the disease. [ABSTRACT FROM AUTHOR]

While the vast majority of pediatric Hodgkin lymphoma (HL) is curable, the prognosis of early relapses and refractory diseases remains poor. Recently, the combination of gemcitabine, vinorelbine, and pegylated liposomal doxorubicin (GVD) displayed encouraging results on adults with relapsed/refractory diseases. Here, we retrospectively report the results of the GVD salvage regimen on four pediatric patients of our ward with a heavily pretreated relapsed/refractory HL. Three of them had nodular sclerosis subtype. They achieved a complete remission after two, three, or four courses of GVD and received high-dose chemotherapy followed by a stem-cell transplantation (auto-auto, auto-allo, and auto). They have been in sustained remission respectively for almost 2, 4, and 5 years. The fourth patient had a lymphocyte-depleted subtype which was initially diagnosed as anaplastic large cell lymphoma. After four courses of GVD, his disease stabilized then progressed again. In total, 15 cycles of GVD were applied to the patients. The toxicity of each course of GVD was mainly hematologic. No cardiotoxicity occurred despite a prior exposure to anthracyclines and radiotherapy. Thus, the GVD combination seems to be an effective pre-transplant rescue treatment for pediatric patients. [ABSTRACT FROM AUTHOR]

Multiple drug resistance remains an unsolved problem in cancer therapy. A previous study has demonstrated that the chemotherapeutic drug doxorubicin (Dox) induced upregulation of P-glycoprotein in endothelial cells, resulting in a 20-fold increase in drug resistance and reduced efficiency of doxorubicin treatment in a mouse tumor model. In the present study, the cross-resistance and sensitivity of HMECd1 and HMECd2 established cell lines to anti-angiogenic drugs, particularly sunitinib, was explored. The results revealed that Dox treatment induced a significant increase in the breast cancer resistance protein (ABCG2) gene transcription and protein expression. This increase gave rise to a 4- to 5-fold increase in the half maximal inhibitory concentration of the HMECd1 and HMECd2 cells in response to sunitinib treatment in vitro. Functionally, the role of ABCG2 in the resistance to sunitinib was confirmed by the use of the ABCG2 inhibitors fumitremorgin C and diethylstilbestrol, which blocked cell resistance. The present study indicates that endothelial cells exhibit cross-resistance between cytotoxic drugs and anti-angiogenic drugs. This suggests that multiple drug resistance induced by chemotherapy in endothelial cells may affect the efficiency of anti-angiogenic drugs. [ABSTRACT FROM AUTHOR]

The dicentric chromosome (9;20) (dic(9;20)) is described in 2 % of childhood B-acute lymphoblastic leukaemia. Fluorescence in situ hybridization (FISH) is the most reliable method to identify dic(9;20) when compared with conventional cytogenetics. To define the prognostic importance of dic(9;20), we evaluated treatment response and patient survival. This was a retrospective study in three French university centres. Patients' clinical and laboratory characteristics and treatment response are described. Nine children with dic(9;20) have been identified since 1995. All patients had at least one poor prognostic feature either among the clinical features, the initial laboratory results or in the initial treatment response: central nervous system involvement (2/9), high median leucocyte count (≥50 G/L) (8/9) and poor response to prednisone (2/9). All patients were in complete cytological remission after induction therapy but only three had a good molecular response with minimal residual disease (MRD) <10. Five out of nine patients relapsed and two died, 4 and 12 months after diagnosis, respectively. The event-free survival rate in this population was 44 % (95 % confidence interval (CI) = 0.09-0.79) and overall survival 78 % (95 % CI = 0.51-1.05). In this population, dic(9;20) is associated with a relatively poor prognosis. Patients showing dic(9;20), whether this cytogenetic abnormality is associated with other poor prognostic factors or not, should be identified at the outset in order to be offered a more intensive treatment protocol. [ABSTRACT FROM AUTHOR]

Background The purpose of this study was to describe the natural history of severe congenital neutropenia (SCN) in 14 patients with G6PC3 mutations and enrolled in the French SCN registry. Methods Among 605 patients included in the French SCN registry, we identified 8 pedigrees that included 14 patients with autosomal recessive G6PC3 mutations. Results Median age at the last visit was 22.4 years. All patients had developed various comordibities, including prominent veins (n = 12), cardiac malformations (n = 12), intellectual disability (n = 7), and myopathic syndrome with recurrent painful cramps (n = 1). Three patients developed Crohn's disease, and five had chronic diarrhea with steatorrhea. Neutropenia was profound (<0.5 × 109/l) in almost all cases at diagnosis and could marginally fluctuate. The bone marrow smears exhibited mild late-stage granulopoeitic defects. One patient developed myelodysplasia followed by acute myelogenous leukemia with translocation (18, 21) at age 14 years, cured by chemotherapy and hematopoietic stem cell transplantation. Four deaths occurred, including one from sepsis at age 5, one from pulmonary late-stage insufficiency at age 19, and two from sudden death, both at age 30 years. A new homozygous mutation (c.249G > A /p.Trp83*) was detected in one pedigree. Conclusions Severe congenital neutropenia with autosomal recessive G6PC3 mutations is associated with considerable clinical heterogeneity. This series includes the first described case of malignancy in this neutropenia. [ABSTRACT FROM AUTHOR]

Bevacizumab is a humanized monoclonal antibody directed against the pro-angiogenic factor vascular and endothelial growth factor-A (VEGF-A) used in the treatment of glioblastomas. Although most patients respond initially to this treatment, studies have shown that glioblastomas eventually recur. Several non-mutually exclusive theories based on the anti-angiogenic effect of bevacizumab have been proposed to explain these mechanisms of resistance. In this report, we studied whether bevacizumab can act directly on malignant glioblastoma cells. We observe changes in the expression profiles of components of the VEGF/VEGF-R pathway and in the response to a VEGF-A stimulus following bevacizumab treatment. In addition, we show that bevacizumab itself acts on glioblastoma cells by activating the Akt and Erks survival signaling pathways. Bevacizumab also enhances proliferation and invasiveness of glioblastoma cells in hyaluronic acid hydrogel. We propose that the paradoxical effect of bevacizumab on glioblastoma cells could be due to changes in the VEGF-A-dependent autocrine loop as well as in the intracellular survival pathways, leading to the enhancement of tumor aggressiveness. Investigation of how bevacizumab interacts with glioblastoma cells and the resulting downstream signaling pathways will help targeting populations of resistant glioblastoma cells. [ABSTRACT FROM AUTHOR]

Multiple drug resistance is still an unsolved problem in cancer therapy. Our previous study demonstrated that the chemotherapeutic drug doxorubicin (Dox) induced upregulation of P-glycoprotein (P-gp) in endothelial cells, resulting in a 20-fold increase in drug resistance and reduced efficiency of Dox treatment in a mice tumor model. In this study, we exposed human microvascular endothelial cells (HMEC-1) to sunitinib, a tyrosine kinase receptor inhibitor, to induce drug resistance. The results show that sunitinib treatment induced multiple drug resistance in these cells. They became resistant not only to sunitinib but also to Dox, paclitaxel, and vinblastine. Significant increases in P-gp (9.3-fold), ABCG2 (breast cancer resistance protein, 1.9-fold), and multidrug resistance-associated protein 1 (2.7-fold) gene transcription were found by quantitative polymerase chain reaction quantification, and their protein expression was confirmed by Western blot. These increases gave rise to an approximately five-fold increase in half maximal inhibitory concentration in these cells in response to sunitinib treatment in vitro. The inhibitors of adenosine triphosphate-binding cassette transporters did not reverse the drug resistance in sunitinib-resistant HMEC-1 cells, assumedly because of a blockage of the pump function caused by sunitinib. Our study indicates that the antiangiogenic drug sunitinib induces multiple drug resistance in endothelial cells. The induction of adenosine triphosphate-binding cassette transporters seems not to be responsible for observed multiple drug resistance, and the underlying mechanisms remain unknown. [ABSTRACT FROM AUTHOR]

Background: Rho GTPases are involved in cellular functions relevant to cancer. The roles of RhoA and Rac1 have already been established. However, the role of Rac3 in cancer aggressiveness is less well understood. Methods: This work was conducted to analyze the implication of Rac3 in the aggressiveness of two breast cancer cell lines, MDA-MB-231 and MCF-7: both express Rac3, but MDA-MB-231 expresses more activated RhoA. The effect of Rac3 in cancer cells was also compared with its effect on the non-tumorigenic mammary epithelial cells MCF- 10A. We analyzed the consequences of Rac3 depletion by anti-Rac3 siRNA. Results: Firstly, we analyzed the effects of Rac3 depletion on the breast cancer cells' aggressiveness. In the invasive MDA-MB-231 cells, Rac3 inhibition caused a marked reduction of both invasion (40%) and cell adhesion to collagen (84%), accompanied by an increase in TNF-induced apoptosis (72%). This indicates that Rac3 is involved in the cancer cells' aggressiveness. Secondly, we investigated the effects of Rac3 inhibition on the expression and activation of related signaling molecules, including NF-κB and ERK. Cytokine secretion profiles were also analyzed. In the non-invasive MCF-7 line; Rac3 did not influence any of the parameters of aggressiveness. Conclusions: This discrepancy between the effects of Rac3 knockdown in the two cell lines could be explained as follows: in the MDA-MB-231 line, the Rac3-dependent aggressiveness of the cancer cells is due to the Rac3/ERK-2/ NF-κB signaling pathway, which is responsible for MMP-9, interleukin-6, -8 and GRO secretion, as well as the resistance to TNF-induced apoptosis, whereas in the MCF-7 line, this pathway is not functional because of the low expression of NF-κB subunits in these cells. Rac3 may be a potent target for inhibiting aggressive breast cancer. [ABSTRACT FROM AUTHOR]

The report describes the case of a young male with a malignant teratoma which was followed by an acute megakaryoblastic leukaemia sharing similar chromosomal abnormalities. In leukemic cells, the authors have obtained cytogenetic evidence by fluorescent in situ hybridisation technique suggesting that this leukaemia arose directly from the germ cell tumour (GCT). The patient received allogenic bone marrow transplantation, which unfortunately, did not prevent the patient to relapse with an undifferentiated sarcoma containing rhabdomyosarcoma components, as well as reappearance of a residual teratoma with metastasis. The treatment strategy for malignant transformation of a GCT seems to be unpredictable and should be dictated by the malignant tissue counterpart. Except for acute leukaemia, unresectable or metastatic settings will generally require multi-modal therapy including chemotherapy, in addition to loco regional approaches. Additionally, long or even a life time follow-up is necessary in patients with poor prognostic characteristics. [ABSTRACT FROM AUTHOR]

In children, lymphoblastic lymphomas represent 30% of Non-Hodgkin lymphomas (NHL), and approximately 15% are precursor B-cell lymphomas (PBLL). Our study evaluated their main clinical characteristics, evolution, and prognosis in three trials. From 1989 to 2008, 53 children with PBLL (median age 7·75 years) were included in three protocols: Malignant Lymphoma Therapy (LMT) 96, European Organization for Research and Treatment of Cancer (EORTC) 58881, and EORTC 58951 using Berlin-Frankfürt-Münster-derived acute lymphoblastic leukaemia (ALL) therapy. There were 10 stage I disease, 9 stage II, 9 stage III and 25 stage IV. Clinical presentation was heterogeneous with a majority of bone lesions and cutaneous or subcutaneous manifestations. At diagnosis 23 patients had bone marrow involvement, and only three had central nervous system involvement. The median follow-up was 74 months. At last follow-up, 45 patients were in continuous complete remission, whereas eight had progressed or had relapsed (7 Stages IV and 1 Stage III) and died. Two patients had a secondary neoplasia, and are still alive. Disease stage was a major prognostic factor, with better overall survival (OS) and event-free survival (EFS) ( P < 0·05) rates observed in patients with Stage I to III as compared to those with Stage IV. Treatment with protocols derived from ALL therapy are efficient with an 82% EFS and an 85% OS at 5 years. [ABSTRACT FROM AUTHOR]

Transient receptor potential canonical (TRPC) channels are key players in calcium homeostasis and various regulatory processes in cell biology. Little is currently known about the TRPC subfamily members in mesenchymal stem cells (MSC), where they could play a role in cell proliferation. We report on the presence of TRPC1, 2, 4 and 6 mRNAs in MSC. Western blot and immunofluorescence staining indicate a membrane and intracellular distribution of TRPC1. Furthermore, the decrease in the level of TRPC1 protein caused by RNA interference is accompanied by the downregulation of cell proliferation. These results indicate that MSC express TRPC1, 2, 4 and 6 mRNA and that TRPC1 may play a role in stem cell proliferation. [ABSTRACT FROM AUTHOR]

The use ofl-asparaginase (l-ASP) in paediatric patients with acute lymphoblastic leukaemia (ALL) is associated with thrombotic complications. We evaluated the activities of tissue factor (TFa), thrombomodulin (TMa) and procoagulant phospholipids (PPL) in 26 consecutive children with ALL (25 B-ALL and one T-ALL) treated by the French Acute Lymphoblastic Leukemia group (FRALLE)-2000 protocol. Samples were obtained at diagnosis, after glucocorticoid (GC) therapy, during the induction phase withl-ASP, vincristine (VCR) and adriamycin (ADR), during the re-induction and within the week after treatment. Plasma levels of TFa, TMa and PPL increased gradually and significantly during the different phases of the treatment, with higher levels observed during the induction period, and decreased after treatment discontinuation. In vitro studies showed that the different drugs used for ALL treatment could induce a weak expression of TF and procoagulant activity (PCA) on normal and leukaemia blood cells, while a marked effect was observed on endothelial cells. In conclusion, these data indicate that, in addition to the well-identified increased in coagulation factors and inhibitor deficiencies, the injury of the endothelium could lead to the release of TF and PPL and could contribute to the hypercoagulability of children treated for ALL. [ABSTRACT FROM AUTHOR]

Background: Infiltration by macrophages (Mϕ) indicates a poor prognosis in breast cancers, in particular by inducing angiogenesis. Our study aimed 1) to investigate the mechanism by which cooperation between Mϕ and aggressive breast cancer cells (MDA-MB-231) induces angiogenesis; 2) to examine the effect of tetrathiomolybdate (TM) on this angiogenic activity. Methods: Mϕ coincubated with MDA-MB-231 were used as a model to mimic the inflammatory microenvironment. Angiogenesis induced by the culture media was tested in the chick chorioallantoic membrane (CAM). Mϕ phenotype was evaluated by 1) expression of the M1 marker CD80, and secretion of interleukin 10 (IL- 10), an M2 marker; 2) capacity to secrete Tumour Necrosis Factor α (TNFα) when stimulated by lipopolysaccharide/ interferon γ (LPS/IFNγ); 3) ability to induce MDA-MB-231 apoptosis. To explore the molecular mechanisms involved, cytokine profiles of conditioned media from MDA-MB-231, Mϕ and the coculture were characterised by an antibody cytokine array. All experiments were carried out both in presence and in absence of TM. Results: Incubation of Mϕ with MDA-MB-231 induced a pro-angiogenic effect in the CAM. It emerged that the angiogenic activity of the coculture is due to the capacity of Mϕ to switch from M1 Mϕ towards M2, probably due to an increase in Macrophage Colony Stimulating Factor. This M1-M2 switch was shown by a decreased expression of CD80 upon LPS/IFNγ stimulation, an increased secretion of IL-10, a decreased secretion of TNFα in response to LPS/IFNγ and an inability to potentiate apoptosis. At the molecular level, the angiogenic activity of the coculture medium can be explained by the secretion of CXC chemokines/ELR+ and CC chemokines. Although TM did not modify either the M2 phenotype in the coculture or the profile of the secreted chemokines, it did decrease the angiogenic activity of the coculture medium, suggesting that TM inhibited angiogenic activity by interfering with the endothelial cell signalling induced by these chemokines. Conclusions: Cooperation between Mϕ and MDA-MB-231 transformed M1 Mϕ to an angiogenic, M2 phenotype, attested by secretion of CXC chemokines/ELR+ and CC chemokines. TM inhibited this coculture-induced increase in angiogenic activity, without affecting either Mϕ phenotype or cytokine secretion profiles. [ABSTRACT FROM AUTHOR]

Since neuroblastoma occurs very early in children's lives, it has been hypothesized that pre- and perinatal factors may play a role in its etiology. This study investigated the role of birth characteristics, congenital malformation and maternal reproductive history in neuroblastoma. The data used were generated by the national population-based case-control study, ESCALE, conducted in France in 2003-2004. The mothers of 191 neuroblastoma cases and 1,681 controls, frequency-matched by age and gender, were interviewed by telephone, using a standardized questionnaire, on several factors including pregnancy, medical history, lifestyle, childhood medical conditions and exposures. A positive association between congenital malformation and all neuroblastoma cases was observed [Odds ratio (OR) = 2.2, 95% confidence interval (95% CI): 1.1-4.5]. Congenital malformations were highly associated to neuroblastoma in children aged less than 1 year (OR = 16.8, 95% CI: 3.1-90), while no association was observed in children aged 1 year or more (OR = 1.0, 95% CI: 0.3-2.9). A negative association with a maternal history of spontaneous abortions was also found (OR = 0.6, 95% CI: 0.4-0.9). The results strongly support the hypothesis that congenital anomalies may be associated with neuroblastoma, particularly in infant (less than 1 year of age). © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Acute lymphoblastic leukemia is the main type of leukemia in children. An infectious etiology has been suspected and the role of the Human herpesvirus-6 (HHV-6) has been suggested. Several studies have tried to establish a link between HHV-6 infections and hematological malignancies, with discordant results. The potential role of HHV-6 in the pathogenesis of pediatric acute lymphoblastic leukemia was investigated. HHV-6 genome copy number was measured by quantitative real-time PCR (RQ-PCR) in bone marrow or peripheral blood samples obtained from 36 children (median age = 4 years) with B acute lymphoblastic leukemia (n = 31) and T acute lymphoblastic leukemia (n = 5) at diagnosis and during complete remission. Positive samples were further characterized to define viral variant, A or B. A total of 24.7% of samples were positive for HHV-6 genome: 13.9% were leukemia samples and 34.1% were complete remission samples. Viral load was low with values lower at diagnosis (median viral copy number = 22.9) than at complete remission (median copy number = 60.1). Among the 17 patients with positive samples, 15 were typed as B-variant whereas 2 could not be typed. These results argue against a role of HHV6 infection in the development of pediatric acute lymphoblastic leukemia. They also suggest that HHV-6 may infect latently bone marrow progenitors but seems not able to infect leukemic cells, raising again the question of the mechanism of virus fusion and entry. This observation shows that a reactivation may be observed during complete remission supporting the possibility of virus reactivation in immunocompromised hosts. J. Med. Virol. 80:689-693, 2008. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Monocytes can be induced to express both tissue factor (TF) and its inhibitor, TF pathway inhibitor-1 (TFPI-1). A short incubation (<6 h) with interleukin (IL)-4 and IL-10, two potent deactivators of monocyte functions, has been shown to modulate the synthesis and expression of TF by monocytes activated by lipopolysaccharide, but the consequences of longer incubations (up to 96 h) on both TF and TFPI-1 are unknown. The results of this study showed that adherent monocytes in culture spontaneously expressed TF and TFPI and that prolonged incubation with IL-10 induced a time- and dose-dependent decrease of monocyte TF synthesis, and an accumulation of TF/TFPI-1 complexes at the moncyte surface, suggesting a decreased clearance of these complexes. In contrast, IL-4 induced a time- and dose-dependent increase in TF synthesis, which remained intracytoplasmic, as shown by confocal microscopy. Surprisingly, TF:antigen (Ag) was decreased at the monocyte surface, but the procoagulant activity (PCA) of IL-4-treated monocytes was increased, as a result of more pronounced decrease of TFPI-1:Ag expression than that of TF. In conclusion, prolonged incubation with IL-4 and IL-10 oppositely modified PCA of cultured monocytes, and altered TF and TFPI trafficking and clearance. These data explain the respective deleterious or benefit effects of IL-4 or IL-10 in atherothrombosis. [ABSTRACT FROM AUTHOR]

Several questions in our understanding of mitochondria are unanswered. These include how the ratio of mitochondrial (mt)DNA to mitochondria is maintained, how the accumulation of defective, rapidly replicating mitochondrial DNA is avoided, how the ratio of mitochondria to cells is adjusted to fit cellular needs, and why any proteins are synthesized in mitochondria rather than simply imported. In bacteria, large hyperstructures or assemblies of proteins, mRNA, lipids and ions have been proposed to constitute a level of organization intermediate between macromolecules and whole cells. Here, we suggest how the concept of hyperstructures together with other concepts developed for bacteria such as transcriptional sensing and spontaneous segregation may provide answers to mitochondrial problems. In doing this, we show how the problem of the very existence of mtDNA brings its own solution. [ABSTRACT FROM AUTHOR]

The involvement of hyaluronic acid (HA) oligosaccharides and blood-derived mononuclear cells in inflammatory processes prompted us to determine whether peripheral blood mononuclear cells (PBMC) possess hyaluronidase activity. PBMC were incubated with macromolecular-tritiated HA at pH 3.8 and supernatants were analysed by size exclusion chromatography to reveal digestion of HA. This digestion was due to the CD14-positive (CD14[SUP+]), adherent, non-specific esterase-positive, subpopulation of PBMC. Hyaluronidase activity (72 kDa) was found in aqueous and non-ionic detergent PBMC extracts but not in the medium in which the cells had been cultured. These results indicate that hyaluronidase is, at least in part, linked to the membrane rather than excreted. Hence, monocytes have one or more hyaluronidases that can generate a pool of active HA fragments within tissues. Hyaluronidase activity was also found in 3/3 myelomonocytic lineage leukaemias but not in 3/3 lymphoblastic leukaemias. [ABSTRACT FROM AUTHOR]

Cerivastatin is used in the treatment of hypercholesterolemia to inhibit 3-hydroxy 3-methylglutaryl coenzyme A reductase and thus prevent the synthesis of cholesterol precursors, such as farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), responsible, respectively, for translocation of Ras and Rho to the cell membrane, a step required for their cell signaling, leading to cell proliferation and migration. Recently, it has been suggested that non lipid-related effects of statins could play a beneficial role in cancer therapy. In this study, we have investigated the mechanisms by which statins inhibit cancer and the types of cancers which could benefit from this therapy. In MDA-MB-231 cells, an aggressive breast cancer cell line with spontaneous activation of Ras and NFκB and overexpression of RhoA, cerivastatin induced inhibition of both cell proliferation and invasion through Matrigel. This anti-proliferative effect was related to G1/S arrest due to an increase in p21Waf1/Cip1. The anti-invasive effect was observed from 18 h and could be explained by RhoA delocalization from the cell membrane, resulting in disorganization of the actin fibers and disappearance of focal adhesion sites. The importance of RhoA inactivation in both these inhibitory effects was proved by their reversion by GGPP but not by FPP. Moreover, cerivastatin was also shown to induce inactivation of NFκB, in a RhoA inhibition-dependent manner, resulting in a decrease in urokinase and metalloproteinase-9 expression, two proteases involved in cell migration. The participation of Ras inactivation is considered a subsidiary mechanism for the effects of cerivastatin, as they were not rescued by FPP. Prolonged treatment of MDA-MB-231 cells with high doses of cerivastatin induced a loss of cell attachment. Interestingly, the effect of cerivastatin was considerably lower on poorly invasive MCF-7 cells. In conclusion, our results suggest that cerivastatin inhibits cell signaling pathways involved in the invasiveness and metastatic properties of highly invasive cancers. [ABSTRACT FROM PUBLISHER]

Interleukin-12 (IL-12), a heterodimeric cytokine with potent biological activity, was evaluated for effects on proliferation of human immature progenitor cells in vitro. In vitro proliferation of 5-FU-resistant CD34+ (G0) peripheral blood stem cells (PBSC) in response to sequential cytokine stimulation was examined in the presence and absence of 100 ng/ml IL-12. PBSC were found to include a subpopulation of cells that were resistant to 25 μg/ml 5-FU and required a combination of IL-12, IL-6 and SCF for the production of morphologically recognizable clonogenic elements at day 14 in semisolid medium. Furthermore, addition of IL-6 soluble receptor (IL-6Rs) to IL-6 and SCF led to a similar recruitment. We also demonstrated a significant production of IL-6Rs by CD34+ cells stimulated by IL-12. We noted that glucocorticoids and aldosterone, a mineralocorticoid, had a positive effect on recruitment, but neither mineralocorticoid nor glucocorticoids induced IL-6Rs production by CD34+ cells. The recruitment mechanism by steroids seemed to be different from that used by IL-12. These results confirm previous findings which showed the involvement of IL-12 on immature PBSCs and suggest that IL-12 might play a key role in early haemopoiesis. [ABSTRACT FROM AUTHOR]

We investigated the use of a new conditioning regimen followed by allogeneic bone marrow transplantation (BMT) for treating children with acute lymphoblastic leukaemia (ALL) after relapse within 6 months of the completion of therapy. One hundred and sixteen children with acute lymphoblastic leukaemia in second or subsequent complete remission (CR) underwent allogeneic bone marrow transplantation from HLA-identical siblings after a preparative regimen comprising total body irradiation (TBI), high-dose cytosine arabinoside and melphalan (TAM regimen). The Kaplan-Meier product-limit estimate (mean ± SE) of disease-free survival (DFS) at 7 years was 59.5 ± 9% (95% confidence interval). The estimated chance of relapse was 22.5 ± 15% with a median follow-up of 88.5 months (range 51–132). 26 patients (22.4%) died with no evidence of recurrent leukaemia, mainly from interstitial pneumonitis, veno-occlusive disease or acute graft-versus-host disease (GVHD). Three factors significantly affected DFS: acute GVHD, site of relapse and, for children in second remission after a marrow relapse, the disease status at the time of transplantation. The DFS were 59.02 ± 12.6%, 37.5 ± 19.8% and 77.4 ± 15% among patients in CR2 after a marrow relapse, in CR3 or in untreated partial marrow relapse, and in CR2 after an isolated CNS relapse, respectively. The lowest DFS was seen in children with acute GVHD grades 3–4. Two significant factors were associated with relapse: the marrow status at the time of transplantation and chronic GVHD. The relapse rate was lower among children in CR2 or with chronic GVHD. We conclude that transplantation after the TAM regimen is an effective therapy for this population with acceptable toxicity, particularly for children in second remission after a very early marrow relapse, or those with early isolated CNS involvement. [ABSTRACT FROM AUTHOR]

Urokinase (uPA) and its receptor (uPAR) have been proposed to be involved in monocyte migration by inducing degradation of matrix proteins. In addition, uPAR is also implicated in cell adhesion to the vascular wall. The adhesive function of uPAR depends on a direct interaction with vitronectin which is increased by uPA and by modification of cell surface integrin (such as CD11b–CD18) when associated to uPAR. In this study we analysed the role of three deactivating cytokines, IL-4, IL-10 and IL-13, on the surface expression of uPA, uPAR and CD11b by monocytes and their consequences on monocyte adhesion to immobilized fibrinogen and vitronectin. IL-10 induced a decrease in uPA and CD11b after 18 h incubation and a delayed decrease in uPAR which was only significant after 48 h incubation. These results may explain the decrease in monocyte adhesion, which was observed after an 18 h incubation with IL-10, on immobilized vitronectin and fibrinogen. In contrast, IL-4 and IL-13 induced a decrease in uPAR after 18 h and a significant increase in uPA both in the cell lysates and at the cell surface, as well as an increase in cell surface associated CD11b. These cytokines did not modify cell adhesiveness to vitronectin or fibrinogen despite the increase in CD11b–CD18. This could be due to the decrease in uPAR because CD11b–CD18/uPAR forms a cell adhesion complex. In addition, the increase in uPA induced by IL-4 could counterbalance the direct interaction of uPAR with vitronectin. The increase in uPA suggests that IL-4 and IL-13 could induce plaque fissuring by monocytes, whereas IL-10 may induce protection against matrix protein degradation by decreasing uPA. [ABSTRACT FROM AUTHOR]

Simple Summary: Osteosarcoma is the most common primary malignant bone tumour in adolescents and young adults. The survival of osteosarcoma patients has not improved for four decades. The purpose was to describe first and subsequent relapses in patients from the OS2006/Sarcome-09 trial, to help future trial design. Among the 434 patients with a confirmed osteosarcoma who achieved CR1 during first line treatment, 157 patients experienced at least one relapse. The 3-year progression-free and overall survival rates were 21% and 37%, respectively. Only a quarter of the patients were included in clinical trials at first recurrence. We want to promote randomised phase-II trials in osteosarcoma relapses, with broad inclusion criteria at study entry in terms of age and disease status, and PFS as primary endpoint. Surgery/local treatment of all residual lesions should be allowed when feasible. Single-arm trial design could be used for subsequent relapses. The purpose was to describe first and subsequent relapses in patients from the OS2006/Sarcome-09 trial, to help future trial design. We prospectively collected and analysed relapse data of all French patients included in the OS2006/Sarcome-09 trial, who had achieved a first complete remission. 157 patients experienced a first relapse. The median interval from diagnosis to relapse was 1.7 year (range 0.5–7.6). The first relapse was metastatic in 83% of patients, and disease was not measurable according to RECIST 1.1 criteria in 23%. Treatment consisted in systemic therapy (74%) and surgical resection (68%). A quarter of the patients were accrued in a phase-II clinical trial. A second complete remission was obtained for 79 patients. Most of them had undergone surgery (76/79). The 3-year progression-free and overall survival rates were 21% and 37%, respectively. In patients who achieved CR2, the 3y-PFS and OS rates were 39% and 62% respectively. Individual correlation between subsequent PFS durations was poor. For osteosarcoma relapses, we recommend randomised phase-II trials, open to patients from all age categories (children, adolescents, adults), not limited to patients with measurable disease (but stratified according to disease status), with PFS as primary endpoint, response rate and surgical CR as secondary endpoints. [ABSTRACT FROM AUTHOR]