Dickkopf-1 Inhibition Reactivates Wnt/ß-Catenin Signaling in Rhabdomyosarcoma, Induces Myogenic Markers In Vitro and Impairs Tumor Cell Survival In Vivo.

The Wnt/ß-catenin signaling pathway plays a pivotal role during embryogenesis and its deregulation is a key mechanism in the origin and progression of several tumors. Wnt antagonists have been described as key modulators of Wnt/ß-catenin signaling in cancer, with Dickkopf-1 (DKK-1) being the most studied member of the DKK family. Although the therapeutic potential of DKK-1 inhibition has been evaluated in several diseases and malignancies, little is known in pediatric tumors. Only a few works have studied the genetic inhibition and function of DKK-1 in rhabdomyosarcoma. Here, for the first time, we report the analysis of the therapeutic potential of DKK-1 pharmaceutical inhibition in rhabdomyosarcoma, the most common soft tissue sarcoma in children. We performed DKK-1 inhibition via shRNA technology and via the chemical inhibitor WAY-2626211. Its inhibition led to ß-catenin activation and the modulation of focal adhesion kinase (FAK), with positive effects on in vitro expression of myogenic markers and a reduction in proliferation and invasion. In addition, WAY-262611 was able to impair survival of tumor cells in vivo. Therefore, DKK-1 could constitute a molecular target, which could lead to novel therapeutic strategies in RMS, especially in those patients with high DKK-1 expression.

Consensus expert recommendations for identification and management of asparaginase hypersensitivity and silent inactivation.

L-asparaginase is an integral component of therapy for acute lymphoblastic leukemia. However, asparaginase-related complications, including the development of hypersensitivity reactions, can limit its use in individual patients. Of considerable concern in the setting of clinical allergy is the development of neutralizing antibodies and associated asparaginase inactivity. Also problematic in the use of asparaginase is the potential for the development of silent inactivation, with the formation of neutralizing antibodies and reduced asparaginase activity in the absence of a clinically evident allergic reaction. Here we present guidelines for the identification and management of clinical hypersensitivity and silent inactivation with Escherichia coli- and Erwinia chrysanthemi- derived asparaginase preparations. These guidelines were developed by a consensus panel of experts following a review of the available published data. We provide a consensus of expert opinions on the role of serum asparaginase level assessment, indications for switching asparaginase preparation, and monitoring after change in asparaginase preparation.

Perceived positive and negative consequences after surviving cancer and their relation to quality of life.

Surviving childhood cancer has multiple implications on both physical and psychological domains of the individual. However, its study and possible effects on health-related quality of life (HRQoL) outcomes of adolescent survivors has been understudied. The objective of this study was twofold; to assess positive and negative cancer-related consequences (psychosocial and physical) in a sample of adolescent cancer survivors and to explore their relationship with HRQoL outcomes. Forty-one participants answered two questions about positive and negative consequences in the aftermath of cancer and filled in the KIDSCREEN-52 self-reported version. Data were analysed using mixed methods approach. Overall, 87.8% of the studied sample identified positive consequences and 63.4% negative consequences in survivorship. Four positive categories and five negative categories with regard to cancer-related consequences were found. Changed perspectives in life narratives seem to be the positive consequence more related to HRQoL (physical well-being, mood & emotions, autonomy, social support & peers), followed by useful life experience (physical well-being, autonomy, social support & peers). Psychological impact was the most referred negative consequence with a significant detrimental effect on social support and peers HRQoL dimension. Even if the majority of survivors reported benefit finding in the aftermath of cancer, concomitant positive and negative consequences have been found. However, findings only reveal a significant relationship between positive narratives and HRQoL, and negative consequences do not seem to have a significant influence on overall HRQoL in survivorship.

TRIB3 silencing promotes the downregulation of Akt pathway and PAX3-FOXO1 in high-risk rhabdomyosarcoma.

Rhabdomyosarcoma (RMS), such as other childhood tumors, has witnessed treatment advancements in recent years. However, high-risk patients continue to face poor survival rates, often attributed to the presence of the PAX3/7-FOXO1 fusion proteins, which has been associated with metastasis and treatment resistance. Despite efforts to directly target these chimeric proteins, clinical success remains elusive. In this study, the main aim was to address this challenge by investigating regulators of FOXO1. Specifically, we focused on TRIB3, a potential regulator of the fusion protein in RMS. Our findings revealed a prominent TRIB3 expression in RMS tumors, highlighting its correlation with the presence of fusion protein. By conducting TRIB3 genetic inhibition experiments, we observed an impairment on cell proliferation. Notably, the knockdown of TRIB3 led to a decrease in PAX3-FOXO1 and its target genes at protein level, accompanied by a reduction in the activity of the Akt signaling pathway. Additionally, inducible silencing of TRIB3 significantly delayed tumor growth and improved overall survival in vivo. Based on our analysis, we propose that TRIB3 holds therapeutic potential for treating the most aggressive subtype of RMS. The findings herein reported contribute to our understanding of the underlying molecular mechanisms driving RMS progression and provide novel insights into the potential use of TRIB3 as a therapeutic intervention for high-risk RMS patients.

Polymorphisms in the methotrexate transport pathway: a new tool for MTX plasma level prediction in pediatric acute lymphoblastic leukemia.

OBJECTIVES: Methotrexate (MTX) is an important component of therapy for pediatric acute lymphoblastic leukemia (ALL). Treatment with MTX often causes toxicity, which can necessitate dose reduction or treatment cessation. Interindividual differences in adverse reactions can be due to different factors, including polymorphisms in key genes. Recently, we confirmed the association between SLCO1B1 rs11045879 polymorphism and toxicity previously proposed by Treviño and colleagues. As SLCO1B1 is a transporter involved in MTX elimination, other polymorphisms in genes from this pathway could also have a role in MTX toxicity. The aim of the present study was to analyze in depth the role of polymorphisms in the genes of the MTX transport pathway as putative toxicity predictors in pediatric ALL. METHODS: We analyzed 384 single nucleotide polymorphisms in 12 transporter genes (SLCO1B1, SLCO1B3, SLCO1A2, ABCB1, ABCG2, ABCC1, ABCC2, ABCC3, ABCC4, SLC19A1, SLC22A6 and SLC22A8) and their correlation with different toxicity parameters in 151 pediatric ALL patients treated using the LAL/SHOP protocol. RESULTS: A significant association with MTX plasma levels was found for 21 polymorphisms from seven genes and 15 haplotypes. After correction, rs9516519 in ABCC4, rs3740065 in ABCC2, and haplotype GCGGG in ABCC2 remained significantly associated. CONCLUSION: Our results suggest that polymorphisms in ABCC4 and ABCC2 could be novel markers for MTX toxicity in pediatric ALL.

Malignancies after hematopoietic cell transplantation for primary immune deficiencies: a report from the Center for International Blood and Marrow Transplant Research.

We describe the incidence of malignancy in patients with primary immunodeficiency disorders (PIDD) following hematopoietic cell transplantation (HCT). From the Center for International Blood and Marrow Transplant Research, 2266 PIDD patients who had undergone allogeneic HCT between 1968 and 2003 were identified. Patient, disease, and transplant factors for development of malignancy were examined and pathology reports for reported malignancies reviewed independently by a pathologist for confirmation. The incidence of malignancy was highest for Wiskott-Aldrich syndrome (3.3%), with an overall incidence of 2.3% for PIDD. Post-HCT malignancy was confirmed for 52 of 63 reported cases. Forty-five of 52 patients developed posttransplant lymphoproliferative disorders (PTLD) at a median of 3 months post-HCT. Of these, 26 had received T cell-depleted (TCD) bone marrow. Three patients who developed myelodysplastic syndrome had received TCD marrow and total body irradiation. Three patients developed a solid tumor. Patients with PIDD are at a relatively low risk of developing malignancies post-HCT compared with their historic risk of cancer. The most frequent malignancy or lymphoproliferative disorder was early-onset PTLD. As in other HCT recipients, TCD appears to correlate with PTLD development. Our results lend support to the hypothesis that immune reconstitution in PIDD following HCT leads to a decrease in cancer risk.

Myeloproliferative disorder in Noonan syndrome.

Children with Noonan syndrome (NS) are at increased risk of developing juvenile myelomonocytic leukemia (JMML) or a myeloproliferative disorder associated with NS (MPD/NS) resembling JMML in the first weeks of life; whereas JMML is an aggressive disorder requiring hematopoietic stem cell transplantation, MPD/NS may resolve without treatment and cases with spontaneous remission have also been reported. Two cases of NS with hematologic disorders are described. Diagnosis of the syndrome was confirmed by the identification of earlier reported germline missense mutations in the PTPN11 gene. Splenomegaly in 1 patient and leukocytosis, monocytosis and "in vitro" culture assays consistent with JMML in both were the most salient hematologic features. After a 24-month follow-up, these 2 infants continue to improve and JMML has been ruled out. Splenomegaly persists in 1 patient and monocytosis in both, but without signs of malignancy, thereby suggesting abnormal hematopoiesis or MPD/NS, as described in NS.

Dickkopf Proteins and Their Role in Cancer: A Family of Wnt Antagonists with a Dual Role.

The Wnt signaling pathway regulates crucial aspects such as cell fate determination, cell polarity and organogenesis during embryonic development. Wnt pathway deregulation is a hallmark of several cancers such as lung, gastric and liver cancer, and has been reported to be altered in others. Despite the general agreement reached by the scientific community on the oncogenic potential of the central components of the pathway, the role of the antagonist proteins remains less clear. Deregulation of the pathway may be caused by overexpression or downregulation of a wide range of antagonist proteins. Although there is growing information related to function and regulation of Dickkopf (DKK) proteins, their pharmacological potential as cancer therapeutics still has not been fully developed. This review provides an update on the role of DKK proteins in cancer and possible potential as therapeutic targets for the treatment of cancer; available compounds in pre-clinical or clinical trials are also reviewed.

Relationship between minimal residual disease measured by multiparametric flow cytometry prior to allogeneic hematopoietic stem cell transplantation and outcome in children with acute lymphoblastic leukemia.

BACKGROUND: The presence of minimal residual disease detected by polymerase chain reaction techniques prior to allogeneic hematopoietic stem cell transplantation has proven to be an independent prognostic factor for poor outcome in children with acute lymphoblastic leukemia. DESIGN AND METHODS: The aim of this study was to ascertain whether the presence of minimal residual disease detected by multiparametric flow cytometry prior to allogeneic hematopoietic stem cell transplantation is related to outcome in children acute lymphoblastic leukemia. Minimal residual disease was quantified by multiparametric flow cytometry at a median of 10 days prior to hematopoietic stem cell transplantation in 31 children (age range, 10 months to 16 years) with acute lymphoblastic leukemia. Thirteen patients were transplanted in first remission. Stem cell donors were HLA-identical siblings in 8 cases and matched unrelated donors in 23. Twenty-six children received a total body irradiation-containing conditioning regimen. According to the level of minimal residual disease, patients were divided into two groups: minimal residual disease-positive (>or=0.01%) (n=10) and minimal residual disease-negative (<0.01%) (n=21). RESULTS: Estimated event-free survival rates at 2 years for the minimal residual disease-negative and -positive subgroups were 74% and 20%, respectively (P=0.004) and overall survival rates were 80% and 20%, respectively (P=0.005). Bivariate analysis identified pre-transplant minimal residual disease as the only significant factor for relapse and also for death (P<0.01). CONCLUSIONS: The presence of minimal residual disease measured by multiparametric flow cytometry identified a group of patients with a 9.5-fold higher risk of relapse and a 3.2-fold higher risk of death than those without minimal residual disease. This study supports the strong relationship between pre-transplantation minimal residual disease measured by multiparametric flow cytometry and outcome following allogeneic hematopoietic stem cell transplantation and concur with the results of previous studies using polymerase chain reaction techniques.

[Quality of life in adolescent survivors of childhood cancer]. / Calidad de vida en adolescentes supervivientes de cáncer infantojuvenil.

BACKGROUND AND OBJECTIVE: To assess health-related quality of life of adolescent survivors of childhood cancer, compared to adolescent's health-related quality of life who had no history of cancer. PATIENTS AND METHOD: A total of 372 adolescents aged between 14 and 19 years, 34 cancer survivors and a comparison group of 338 peers without a history of cancer, were assessed. All of them filled in the SF-12v(2) in a cross-sectional study. RESULTS: Survivors revealed significantly higher mean values compared to the normative group for the Mental Component Scale (MCS) from the SF-12v(2) (52,60 vs. 47,85; p=0,004; IC 95%, -7,9--1,6). No significant differences between groups were found for the Physical Component Scale (PCS), even though adolescent survivors of childhood cancer showed higher mean scores (54,03 vs. 52,72). CONCLUSIONS: Adolescent cancer survivors showed a satisfactory quality of life (mean scores around the normative values), and, specifically, they reported greater perception of psychological wellbeing compared to peers.

Hedgehog Pathway Inhibition Hampers Sphere and Holoclone Formation in Rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most common type of soft tissue sarcoma in children and can be divided into two main subtypes: embryonal (eRMS) and alveolar (aRMS). Among the cellular heterogeneity of tumors, the existence of a small fraction of cells called cancer stem cells (CSC), thought to be responsible for the onset and propagation of cancer, has been demonstrated in some neoplasia. Although the existence of CSC has been reported for eRMS, their existence in aRMS, the most malignant subtype, has not been demonstrated to date. Given the lack of suitable markers to identify this subpopulation in aRMS, we used cancer stem cell-enriched supracellular structures (spheres and holoclones) to study this subpopulation. This strategy allowed us to demonstrate the capacity of both aRMS and eRMS cells to form these structures and retain self-renewal capacity. Furthermore, cells contained in spheres and holoclones showed significant Hedgehog pathway induction, the inhibition of which (pharmacologic or genetic) impairs the formation of both holoclones and spheres. Our findings point to a crucial role of this pathway in the maintenance of these structures and suggest that Hedgehog pathway targeting in CSC may have great potential in preventing local relapses and metastases.

Treatment of nonmetastatic rhabdomyosarcoma in childhood and adolescence: third study of the International Society of Paediatric Oncology--SIOP Malignant Mesenchymal Tumor 89.

PURPOSE: To improve outcome for children with nonmetastatic rhabdomyosarcoma and to reduce systematic use of local therapy. PATIENTS AND METHODS: Five hundred three previously untreated patients aged from birth to 18 years, recruited between 1989 and 1995, were allocated to one of six treatment schedules by site and stage. RESULTS: Five-year overall survival (OS) and event-free survival (EFS) were 71% and 57%, respectively. Primary site, T-stage, and pathologic subtype were independent factors in predicting OS by multivariate analysis. Differences between EFS and OS reflected local treatment strategy and successful re-treatment for some patients after relapse. Patients with genitourinary nonbladder prostate tumors had the most favorable outcome (5-year OS, 94%): the majority were boys with paratesticular tumors treated successfully without alkylating agents. Patients with stage III disease treated with a novel six-drug combination showed improved survival compared with the Malignant Mesenchymal Tumor 84 study (MMT 84; 5-year OS, 60% v 42%, respectively). OS was not significantly better than that achieved in the previous MMT 84 study, but 49% of survivors were cured without significant local therapy. CONCLUSION: Selective avoidance of local therapy is justified in some patients, though further work is required to prospectively identify those for whom this is most applicable. Exclusion of alkylating agents is justified for the most favorable subset of patients. The value of the new six-drug chemotherapy combination is being evaluated further in a randomized study (MMT 95).

Childhood soft tissue sarcomas incidence and survival in European children (1978-1997): report from the Automated Childhood Cancer Information System project.

This population-based study is based on 5802 cases of soft tissue sarcomas (STS) in children aged 0-14 years extracted from the database of the Automated Childhood Cancer Information System (ACCIS) and registered in population-based cancer registries in Europe for the period 1978-1997. STS represent almost 8% of neoplasms in children, almost half of whom are less than 5 years at diagnosis. Rhabdomyosarcoma is the most frequent childhood STS (50%). During 1988-1997 the age-standardised incidence of STS in Europe was 9.1 per million children, lowest in the West and East and highest in the North. The incidence of STS increased almost 2% per year over the period 1978-1997, attributable mostly to increase in genito-urinary rhabdomyosarcoma. Prognosis of children with STS was related to age and site of tumour. Five-year survival of children with STS increased from 46% in 1978-1977 to 66% in 1993-1997, reaching 74% in the North for those diagnosed in 1993-1997. This improvement is ascribed to therapy advances.

Successful Treatment of Sinusitis by Acanthamoeba in a Pediatric Patient After Allogeneic Stem Cell Transplantation.

Acanthamoeba infections are rare and mostly occur in immunocompromised patients. Most of the reported cases after stem cell transplantation have been diagnosed postmortem. We present the case of a 3-year-old boy with chronic graft versus host disease post hematopoietic transplantation, who was successfully treated for Acanthamoeba.

MicroRNA-497 impairs the growth of chemoresistant neuroblastoma cells by targeting cell cycle, survival and vascular permeability genes.

Despite multimodal therapies, a high percentage of high-risk neuroblastoma (NB) become refractory to current treatments, most of which interfere with cell cycle and DNA synthesis or function, activating the DNA damage response (DDR). In cancer, this process is frequently altered by deregulated expression or function of several genes which contribute to multidrug resistance (MDR). MicroRNAs are outstanding candidates for therapy since a single microRNA can modulate the expression of multiple genes of the same or different pathways, thus hindering the development of resistance mechanisms by the tumor. We found several genes implicated in the MDR to be overexpressed in high-risk NB which could be targeted by microRNAs simultaneously. Our functional screening identified several of those microRNAs that reduced proliferation of chemoresistant NB cell lines, the best of which was miR-497. Low expression of miR-497 correlated with poor patient outcome. The overexpression of miR-497 reduced the proliferation of multiple chemoresistant NB cell lines and induced apoptosis in MYCN-amplified cell lines. Moreover, the conditional expression of miR-497 in NB xenografts reduced tumor growth and inhibited vascular permeabilization. MiR-497 targets multiple genes related to the DDR, cell cycle, survival and angiogenesis, which renders this molecule a promising candidate for NB therapy.

New splicing variants for human Tyrosine Hydroxylase gene with possible implications for the detection of minimal residual disease in patients with neuroblastoma.

Expression of Tyrosine Hydroxylase (TH) is frequently seen in neuroblastomas, the most common extracranial tumor in children, and TH mRNA detection is used for the analysis of microcirculating or micrometastatic disease in this neoplasia. TH is known to have at least seven isoforms produced by alternative splicing of the N-terminal region (exons 1-4), although no other splicing variants have been described downstream. TH expression was analyzed in six samples of neuroblastoma by RT-PCR using highly restrictive conditions and primers between exons 5 and 12, a region of the gene previously considered to be constant. In the analyzed samples we found two novel TH mRNAs, one lacking exon 8, and another lacking exons 8+9. These new splicing variants are described in a region of TH previously reported to be conserved, and that has been used for the design of reverse transcriptase-polymerase chain-reaction assays for the detection of minimal residual disease [Eur. J. Cancer, 27 (1991) 762]. The splicing pattern characteristic of every tumor could allow the monitoring of the minimal residual disease in a tumor-specific manner.

Expression of multidrug resistance-1 and multidrug resistance-associated protein genes in pediatric rhabdomyosarcoma.

Overexpression of multidrug resistance-1 (MDR-1), and multidrug resistance-associated protein (MRP) genes has been linked with resistance to chemotherapy in vitro and in vivo. Their role in chemotherapy resistance in pediatric rhabdomyosarcoma is unclear. The study was undertaken to analyze the expression of MDR-1 and MRP genes in the embryonal and the alveolar subtypes of rhabdomyosarcoma and to elucidate its clinical relevance. Twenty-three rhabdomyosarcoma samples were analyzed for the expression of MDR-1 and MRP genes using a semi-quantitative competitive RT-PCR assay. MRP gene expression was associated with a reduction in survival (p=0.02). The overall survival of patients with tumors positive or negative for MRP expression were 50% (95% confidence interval, 30-70%) and 93% (95% confidence interval, 76-100%) respectively. In contrast, the expression of MDR-1 gene was not predictive of survival. These findings suggest that MRP expression could be a prognostic factor in patients with rhabdomyosarcoma.

The role of leptin in diencephalic syndrome.

Diencephalic syndrome is a rare condition associated with central nervous system tumors. The most common presentation is secondary failure to thrive with proper caloric intake and no statural impairment. Despite the importance of this syndrome, little is known of its pathophysiology. Some reports have documented changes in human growth hormone and insulin levels at the onset, whereas others have described endocrine disorders of hypothalamic insufficiency resulting from surgery of the tumor. It has been suggested that the hormonal changes described, such as increased human growth hormone and ghrelin or decreased insulin and leptin levels, are related to a patient's BMI. These findings support the role of these 4 hormones as indicators of the patient's nutritional status but not as mediators or potential therapeutic targets of the disease. We report the case of an infant who initially presented with tumor progression and, after chemotherapy, progressive weight gain and reduced tumor size. Because he presented no hormonal deficiencies or obesity after therapy, we were able to analyze his hormonal status uninfluenced by effects of metabolic treatment or excess weight. Although ghrelin and leptin levels have been related to nutritional status, our patient's leptin levels fell when tumor size decreased and weight increased: an extraordinary finding because leptin concentration is expected to increase with weight gain. This paradoxical response suggests that leptin may be dysregulated in diencephalic syndrome or that the diencephalic astrocytoma may have had an effect on leptin secretion.

Surviving childhood cancer: relationship between exercise and coping on quality of life.

This research assesses Health-Related Quality of Life (HRQoL) in a Spanish sample of adolescent cancer survivors, and analyzes the relationship between HRQoL, coping styles and physical exercise. Forty-two survivors (12-19 years), who were ≥ 1 year of remission, completed standardized measures of HRQoL (CHIP-AE), coping strategies (ACS) and physical exercise (AECEF). Mean scores in all HRQoL domains were within normative values. Multiple regression analysis revealed that physical exercise and productive coping were related to higher HRQoL, whereas non-productive coping was related to lower HRQoL. This sample of survivors reported good levels of HRQoL, which are mediated by coping styles and physical exercise.