Comparing self-reported physical activity and sedentary time to objective fitness measures in a military cohort.

OBJECTIVES: Regular vigorous physical activity (PA) and high levels of physical fitness (PF) confer health benefits. Conversely, sedentary time is a risk factor for chronic illness, independent of PA. We evaluated associations between self-reported PA, sedentary time, and objective PF measures in military Service members. DESIGN: Cross-sectional study including 10,105 Air Force Millennium Cohort participants with a valid physical fitness assessment (PFA). METHODS: Linear regression assessed associations between self-report PA, screen time, and usual activity and abdominal circumference (AC) and VO2 max; logistic regression was used for PFA failure. We stratified by age and sex. RESULTS: Men who self-reported high versus low levels of PA had greater AC (19-29 years: ß=0.23in., 95% CI 0.07, 0.39; 30-39 years: ß=0.45in., 95% CI 0.17, 0.72). High versus low self-reported PA was also associated with greater VO2Max (ß=:0.81-1.41mL/kg/min). Self-reported strength training for ≥2days/week was associated with greater VO2Max in 19-29year old men (ß=0.84mL/kg/min, 95% CI 0.09, 0.60) and 30-39year old women (ß=0.74mL/kg/min, 95% CI 0.02, 1.46). For younger men and women,<2h of screen time/day was associated with greater VO2Max (Males 19-29years: ß=0.23mL/kg/min, 95% CI 0.44, 1.26; Females 19-29years: ß=0.83mL/kg/min, 95% CI 0.25, 1.42). PA was not associated with PFA failure, while screen time was (Males OR: 0.32-0.65, 95% CI 0.17-0.92, p<0.001-0.016). CONCLUSIONS: Self-reported PA and screen time were associated with some objective PF measures, including VO2Max and AC. However, screen time alone was associated with PFA failure.

Synthetic high-density lipoprotein nanoconjugate targets neuroblastoma stem cells, blocking migration and self-renewal.

BACKGROUND: Pathways critical for neuroblastoma cancer stem cell function are targeted by 4,19,27-triacetyl withalongolide A (WGA-TA). Because neuroblastoma cells and their cancer stem cells highly overexpress the scavenger receptor class B type 1 receptor that binds to synthetic high-density lipoprotein, we hypothesized that a novel mimetic synthetic high-density lipoprotein nanoparticle would be an ideal carrier for the delivery of 4,19,27-triacetyl withalongolide to neuroblastoma and neuroblastoma cancer stem cells. METHODS: Expression of scavenger receptor class B type 1 in validated human neuroblastoma cells was evaluated by quantitative polymerase chain reaction (qPCR) and Western blot. In vitro cellular uptake of synthetic high-density lipoprotein nanoparticles was observed with a fluorescence microscope. In vivo biodistribution of synthetic high-density lipoprotein nanoparticles was investigated with IVIS imaging. Self-renewal and migration/invasion were assessed by sphere formation and Boyden chamber assays, respectively. Viability was analyzed by CellTiter-Glo assay. Cancer stem cell markers were evaluated by flow cytometry. RESULTS: qPCR and Western blot analysis revealed a higher level of scavenger receptor class B type 1 expression and drug uptake in N-myc amplified neuroblastoma cells. In vitro uptake of synthetic high-density lipoprotein was almost completely blocked by excess synthetic high-density lipoprotein. The synthetic high-density lipoprotein nanoparticles mainly accumulated in the tumor and liver, but not in other organs. Synthetic HDL-4,19,27-triacetyl withalongolide showed a 1,000-fold higher potency than the carrier (synthetic high-density lipoprotein) alone (P < .01) to kill neuroblastoma cells. Additionally, a dose-dependent decrease in sphere formation, invasion, migration, and cancer stem cell markers was observed after treatment of neuroblastoma cells with synthetic high-density lipoprotein-4,19,27-triacetyl withalongolide A. CONCLUSION: Synthetic high-density lipoprotein is a promising platform to improve the delivery of anticancer drug 4,19,27-triacetyl withalongolide A to neuroblastomas and neuroblastoma cancer stem cells through SR-B1 targeting in vitro and in vivo.

Imatinib Treatment in PDGFRA-Negative Childhood Hypereosinophilic Syndrome.

We report a 4-year-old female who presented with severe hypereosinophilia (215.7 K/µl) and end-organ dysfunction. Extensive evaluation including whole exome sequencing was performed, revealing no causative mutation. Initial treatment with corticosteroids, leukapheresis, and hydroxyurea decreased her absolute eosinophil count (AEC), although it remained elevated. Despite the absence of a PDGFRA mutation, an imatinib trial resulted in normalization of her AEC. Imatinib was discontinued after sustained normal counts for 1 month. AECs have remained normal for more than 1 year off therapy. This provides support for consideration of imatinib in the treatment of hypereosinophilia even in the absence of a known tyrosine kinase mutation.

Integrative Clinical Sequencing in the Management of Refractory or Relapsed Cancer in Youth.

IMPORTANCE: Cancer is caused by a diverse array of somatic and germline genomic aberrations. Advances in genomic sequencing technologies have improved the ability to detect these molecular aberrations with greater sensitivity. However, integrating them into clinical management in an individualized manner has proven challenging. OBJECTIVE: To evaluate the use of integrative clinical sequencing and genetic counseling in the assessment and treatment of children and young adults with cancer. DESIGN, SETTING, AND PARTICIPANTS: Single-site, observational, consecutive case series (May 2012-October 2014) involving 102 children and young adults (mean age, 10.6 years; median age, 11.5 years, range, 0-22 years) with relapsed, refractory, or rare cancer. EXPOSURES: Participants underwent integrative clinical exome (tumor and germline DNA) and transcriptome (tumor RNA) sequencing and genetic counseling. Results were discussed by a precision medicine tumor board, which made recommendations to families and their physicians. MAIN OUTCOMES AND MEASURES: Proportion of patients with potentially actionable findings, results of clinical actions based on integrative clinical sequencing, and estimated proportion of patients or their families at risk of future cancer. RESULTS: Of the 104 screened patients, 102 enrolled with 91 (89%) having adequate tumor tissue to complete sequencing. Only the 91 patients were included in all calculations, including 28 (31%) with hematological malignancies and 63 (69%) with solid tumors. Forty-two patients (46%) had actionable findings that changed their cancer management: 15 of 28 (54%) with hematological malignancies and 27 of 63 (43%) with solid tumors. Individualized actions were taken in 23 of the 91 (25%) based on actionable integrative clinical sequencing findings, including change in treatment for 14 patients (15%) and genetic counseling for future risk for 9 patients (10%). Nine of 91 (10%) of the personalized clinical interventions resulted in ongoing partial clinical remission of 8 to 16 months or helped sustain complete clinical remission of 6 to 21 months. All 9 patients and families with actionable incidental genetic findings agreed to genetic counseling and screening. CONCLUSIONS AND RELEVANCE: In this single-center case series involving young patients with relapsed or refractory cancer, incorporation of integrative clinical sequencing data into clinical management was feasible, revealed potentially actionable findings in 46% of patients, and was associated with change in treatment and family genetic counseling for a small proportion of patients. The lack of a control group limited assessing whether better clinical outcomes resulted from this approach than outcomes that would have occurred with standard care.

Alternative NHEJ Pathway Components Are Therapeutic Targets in High-Risk Neuroblastoma.

UNLABELLED: In neuroblastoma, MYCN genomic amplification and segmental chromosomal alterations including 1p or 11q loss of heterozygocity and/or 17q gain are associated with progression and poor clinical outcome. Segmental alterations are the strongest predictor of relapse and result from unbalanced translocations attributable to erroneous repair of chromosomal breaks. Although sequence analysis of affected genomic regions suggests that these errors arise by nonhomologous end-joining (NHEJ) of DNA double-strand breaks (DSB), abnormalities in NHEJ have not been implicated in neuroblastoma pathogenesis. On this basis, the hypothesis that an error-prone mechanism of NHEJ is critical for neuroblastoma cell survival was tested. Plasmid-based DSB repair assays demonstrated efficient NHEJ activity in human neuroblastoma cells with repair products that were error-prone relative to nontransformed cells. Neuroblastoma cells derived from tumorigenic neuroblastic phenotypes had differential DNA repair protein expression patterns compared with nontumorigenic cells. Tumorigenic neuroblastoma cells were deficient in DNA ligase IV (Lig4) and Artemis (DCLRE1C), mediators of canonical NHEJ. Conversely, enzymes required for an error-prone alternative NHEJ pathway (alt-NHEJ), DNA Ligase IIIα (Lig3), DNA Ligase I (Lig1), and PARP1 protein were upregulated. Inhibition of Lig3 and Lig1 led to DSB accumulation and cell death, linking alt-NHEJ to cell survival in neuroblastoma. Neuroblastoma cells demonstrated sensitivity to PARP1 inhibition (PARPi) that paralleled PARP1 expression. In a dataset of human neuroblastoma patient tumors, overexpression of genes encoding alt-NHEJ proteins associated with poor survival. IMPLICATIONS: These findings provide an insight into DNA repair fidelity in neuroblastoma and identify components of the alt-NHEJ pathway as promising therapeutic targets.

CREB-binding protein regulates Ku70 acetylation in response to ionization radiation in neuroblastoma.

Ku70 was originally described as an autoantigen, but it also functions as a DNA repair protein in the nucleus and as an antiapoptotic protein by binding to Bax in the cytoplasm, blocking Bax-mediated cell death. In neuroblastoma (NB) cells, Ku70's binding with Bax is regulated by Ku70 acetylation such that increasing Ku70 acetylation results in Bax release, triggering cell death. Although regulating cytoplasmic Ku70 acetylation is important for cell survival, the role of nuclear Ku70 acetylation in DNA repair is unclear. Here, we showed that Ku70 acetylation in the nucleus is regulated by the CREB-binding protein (CBP), and that Ku70 acetylation plays an important role in DNA repair in NB cells. We treated NB cells with ionization radiation and measured DNA repair activity as well as Ku70 acetylation status. Cytoplasmic and nuclear Ku70 were acetylated after ionization radiation in NB cells. Interestingly, cytoplasmic Ku70 was redistributed to the nucleus following irradiation. Depleting CBP in NB cells results in reducing Ku70 acetylation and enhancing DNA repair activity in NB cells, suggesting nuclear Ku70 acetylation may have an inhibitory role in DNA repair. These results provide support for the hypothesis that enhancing Ku70 acetylation, through deacetylase inhibition, may potentiate the effect of ionization radiation in NB cells.

Thalidomide therapy for aggressive histiocytic lesions in the pediatric population.

Aggressive histiocytic lesions are uncommon in the pediatric population. These neoplasms occur in isolation or after therapy for other types of hematopoietic malignancy such as T-cell acute lymphoblastic leukemia. The etiology of these lesions is poorly understood, and no definitive standard of care has been established for patients with these diagnoses. Here, we report the success of thalidomide treatment for 2 subtypes of histiocytic proliferation--metastatic histiocytic sarcoma and extracutaneous juvenile xanthogranuloma--in pediatric patients. Our findings highlight the importance of considering thalidomide therapy in this unique and difficult to treat patient population.

HDAC6 deacetylates Ku70 and regulates Ku70-Bax binding in neuroblastoma.

Ku70 was first characterized as a nuclear factor that binds DNA double-strand breaks in nonhomolog end-joining DNA repair. However, recent studies have shown that Ku70 is also found in the cytoplasm and binds Bax, preventing Bax-induced cell death. We have shown that, in neuroblastoma cells, the binding between Ku70 and Bax depends on the acetylation status of Ku70, such that, when Ku70 is acetylated, Bax is released from Ku70, triggering cell death. Thus, to survive, in neuroblastoma cells, cytoplasmic Ku70 acetylation status is carefully regulated such that Ku70 is maintained in a deacetylated state, keeping Bax complexed with Ku70. We have shown that overexpression of CREB-binding protein (CBP), a known acetyltransferase that acetylates Ku70, releases Bax from Ku70, triggering apoptosis. Although we have shown that blocking deacetylase activity using non-type-specific inhibitors also triggers Ku70 acetylation and Bax-dependent cell death, the targets of these deacetylase inhibitors in neuroblastoma cells remain unknown. Here, we demonstrate that, in neuroblastoma cells, histone deacetylase 6 (HDAC6) binds Ku70 and Bax in the cytoplasm and that knocking down HDAC6 or using an HDAC6-specific inhibitor triggers Bax-dependent cell death. Our results show that HDAC6 regulates the interaction between Ku70 and Bax in neuroblastoma cells and may be a therapeutic target in this pediatric solid tumor.

Isolated infrarenal caval disruption secondary to minimal blunt trauma.

Injuries to the inferior vena cava (IVC) are highly lethal and are usually associated with gunshot wounds. Blunt injury to the IVC is a rare entity that is usually located in the retrohepatic space. We present the case of an infrarenal caval disruption in a 9-year-old as a result of minimal blunt trauma. A computed tomography scan showed that the patient had a large retroperitoneal hematoma associated with IVC disruption and proximal thrombus just below the renal veins. There was no evidence of either arterial or other intra-abdominal injuries. The patient had a fall in hematocrit and abdominal tenderness prompting operative exploration. Before laparotomy, bilateral balloon occlusion devices were placed in both femoral veins. The patient was noted to have a total disruption of his IVC just above the origin of his iliac veins. The anterior two-third of the IVC was avulsed, thus leaving the posterior portion against the retroperitoneum. Given the patient's hemodynamic instability and amount of venous damage, the IVC was oversewn and a damage control operation was undertaken. The following day, the patient was brought back to the operating room for a second-look laparotomy and abdominal closure. A pathologic examination revealed a high-grade spindle cell sarcoma. Blunt injury to the IVC is a rare entity and its location outside of the retrohepatic space should alert the surgeon to a potential underlying malignant etiology.

Microscopic polyangiitis in an adolescent presenting as severe anemia and syncope.

Microscopic polyangiitis (MPA) is an autoimmune systemic vasculitis of small vessels. The condition has been best characterized in older adults and little is known of the natural history of this disease in children and adolescents. In this report, a case of an adolescent presenting with symptomatic anemia and syncopal episodes is described. An extensive evaluation ultimately led to the diagnosis of MPA. The unique findings in this case and review of the literature are presented, outlining the variable clinical presentations and challenge of diagnosing this condition in pediatric patients.

CLU blocks HDACI-mediated killing of neuroblastoma.

Clusterin is a ubiquitously expressed glycoprotein with multiple binding partners including IL-6, Ku70, and Bax. Clusterin blocks apoptosis by binding to activated Bax and sequestering it in the cytoplasm, thereby preventing Bax from entering mitochondria, releasing cytochrome c, and triggering apoptosis. Because increased clusterin expression correlates with aggressive behavior in tumors, clusterin inhibition might be beneficial in cancer treatment. Our recent findings indicated that, in neuroblastoma cells, cytoplasmic Bax also binds to Ku70; when Ku70 is acetylated, Bax is released and can initiate cell death. Therefore, increasing Ku70 acetylation, such as by using histone deacetylase inhibitors, may be therapeutically useful in promoting cell death in neuroblastoma tumors. Since clusterin, Bax, and Ku70 form a complex, it seemed likely that clusterin would mediate its anti-apoptotic effects by inhibiting Ku70 acetylation and blocking Bax release. Our results, however, demonstrate that while clusterin level does indeed determine the sensitivity of neuroblastoma cells to histone deacetylase inhibitor-induced cell death, it does so without affecting histone deacetylase-inhibitor-induced Ku70 acetylation. Our results suggest that in neuroblastoma, clusterin exerts its anti-apoptotic effects downstream of Ku70 acetylation, likely by directly blocking Bax activation.

Ku70 acetylation in neuroblastoma pathogenesis and therapy.

Neuroblastoma is a cancer that occurs in children. It develops from stem cells that normally give rise to parts of the peripheral nervous system and adrenal glands. Although most children with localized neuroblastoma are cured, children with wide-spread disease have a small chance of survival even after surgery, chemotherapy, radiation and bone marrow transplantation. Ten to fifteen percent of patients die from treatment complications, and long-term survival is less than 30%. Although contemporary molecular tumor marker discoveries have improved prognostication, few have led to new therapeutic approaches. To solve this problem, we are working to understand which molecules in the stem cells from which this cancer arises malfunction to cause neuroblastoma and apply this information to develop new models to treat this disease. Our efforts have focused on the functional regulation of a protein called Ku70, which coordinately regulates DNA repair and cell death. We propose that the incorrect balance between these two activities underlies this cancer's development, and that re-balancing with drug therapy offers a way to treat this disease.

FDG PET imaging of childhood sarcomas.

BACKGROUND: Positron-emission tomography (PET) imaging using [(18)F]fluorodeoxyglucose (FDG) is useful for detection, staging, and monitoring a variety of malignancies, including lymphoma, in adults, but its utility in sarcomas, especially soft tissue sarcomas (STS), in children and young adults is not clear. PROCEDURE: To evaluate the potential utility of FDG PET in the care of STS in children and young adults, we analyzed 46 PET scans in 25 patients acquired over 12 years. Scans were interpreted by two imaging physicians blinded to findings from other imaging studies and clinical information. Results were compared with computed tomography and magnetic resonance imaging, biopsy results, where available, and clinical follow-up of at least 12 months. RESULTS: For a total of 46 scans in 25 patients, there were 25 true-positive scans, 3 false-positive scans, 12 true-negative scans, and 6 false-negative scans. The sensitivity of the PET scan was 86%, specificity was 80%, positive predictive value was 89%, and negative predictive value was 67%. CONCLUSION: FDG PET may be a useful imaging modality in the management of children and young adults with STS, although prospective studies are needed to establish its true utility.