[Show abstract][Hide abstract] ABSTRACT: IMPORTANCE Monitoring young children with optic pathway gliomas (OPGs) for visual deterioration can be difficult owing to age-related noncompliance. Optical coherence tomography (OCT) measures of retinal nerve fiber layer (RNFL) thickness have been proposed as a surrogate marker of vision but this technique is also limited by patient cooperation. OBJECTIVE To determine whether measures of circumpapillary RNFL thickness, acquired with handheld OCT (HH-OCT) during sedation, can differentiate between young children with and without vision loss from OPGs. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional analysis of a prospective observational study was conducted at a tertiary-care children's hospital. Children with an OPG (sporadic or secondary to neurofibromatosis type 1) who were cooperative for visual acuity testing, but required sedation to complete magnetic resonance imaging, underwent HH-OCT imaging of the circumpapillary RNFL while sedated. MAIN OUTCOMES AND MEASURES Area under the curve of the receiver operating characteristic, sensitivity, specificity, positive predictive value, and negative predictive value of the average and quadrant-specific RNFL thicknesses. RESULTS Thirty-three children (64 eyes) met inclusion criteria (median age, 4.8 years; range, 1.8-12.6 years). In children with vision loss (abnormal visual acuity and/or visual field), RNFL thickness was decreased in all quadrants compared with the normal-vision group (P < .001 for all comparisons). Using abnormal criteria of less than 5% and less than 1%, the area under the curve was highest for the average RNFL thickness (0.96 and 0.97, respectively) compared with specific anatomic quadrants. The highest discrimination and predictive values were demonstrated for participants with 2 or more quadrants meeting less than 5% (sensitivity = 93.3; specificity = 97.9; positive predictive value = 93.3; and negative predictive value = 97.9) and less than 1% (sensitivity = 93.3; specificity = 100; positive predictive value = 100; and negative predictive value = 98.0) criteria. CONCLUSIONS AND RELEVANCE Measures of RNFL thickness acquired with HH-OCT during sedation can differentiate between young children with and without vision loss from OPGs. For young children who do not cooperate with vision testing, HH-OCT measures may be a surrogate marker of vision. Longitudinal studies are needed to delineate the temporal relationship between RNFL decline and vision loss.
[Show abstract][Hide abstract] ABSTRACT: Diffuse intrinsic pontine glioma (DIPG) is a highly morbid form of pediatric brainstem glioma. Here, we present the first comprehensive protein, mRNA, and methylation profiles of fresh-frozen DIPG specimens (n = 14), normal brain tissue (n = 10), and other pediatric brain tumors (n = 17). Protein profiling identified 2,305 unique proteins indicating distinct DIPG protein expression patterns compared to other pediatric brain tumors. Western blot and immunohistochemistry validated upregulation of Clusterin (CLU), Elongation Factor 2 (EF2), and Talin-1 (TLN1) in DIPGs studied. Comparisons to mRNA expression profiles generated from tumor and adjacent normal brain tissue indicated two DIPG subgroups, characterized by upregulation of Myc (N-Myc) or Hedgehog (Hh) signaling. We validated upregulation of PTCH, a membrane receptor in the Hh signaling pathway, in a subgroup of DIPG specimens. DNA methylation analysis indicated global hypomethylation of DIPG compared to adjacent normal tissue specimens, with differential methylation of 24 genes involved in Hh and Myc pathways, correlating with protein and mRNA expression patterns. Sequencing analysis showed c.83A>T mutations in the H3F3A or HIST1H3B gene in 77 % of our DIPG cohort. Supervised analysis revealed a unique methylation pattern in mutated specimens compared to the wild-type DIPG samples. This study presents the first comprehensive multidimensional protein, mRNA, and methylation profiling of pediatric brain tumor specimens, detecting the presence of two subgroups within our DIPG cohort. This multidimensional analysis of DIPG provides increased analytical power to more fully explore molecular signatures of DIPGs, with implications for evaluating potential molecular subtypes and biomarker discovery for assessing response to therapy.
[Show abstract][Hide abstract] ABSTRACT: The tumor suppressor gene HIC1 (Hypermethylated In Cancer 1) is located in 17p13.3 a region frequently hypermethylated or deleted in tumors and in a contiguous-gene syndrome, the Miller-Dieker syndrome which includes classical lissencephaly (smooth brain) and severe developmental defects. HIC1 encodes a transcriptional repressor involved in the regulation of growth control, DNA damage response and cell migration properties. We previously demonstrated that the membrane-associated G-protein-coupled receptors CXCR7, ADRB2 and the tyrosine kinase receptor EphA2 are direct target genes of HIC1. Here we show that ectopic expression of HIC1 in U2OS and MDA-MB-231 cell lines decreases expression of the ApoER2 and VLDLR genes, encoding two canonical tyrosine kinase receptors for Reelin. Conversely, knock-down of endogenous HIC1 in BJ-Tert normal human fibroblasts through RNA interference results in the up-regulation of these two Reelin receptors. Finally, through chromatin immunoprecipitation (ChIP) in BJ-Tert fibroblasts, we demonstrate that HIC1 is a direct transcriptional repressor of ApoER2 and VLDLR. These data provide evidence that HIC1 is a new regulator of the Reelin pathway which is essential for the proper migration of neuronal precursors during the normal development of the cerebral cortex, of Purkinje cells in the cerebellum and of mammary epithelial cells. Deregulation of this pathway through HIC1 inactivation or deletion may contribute to its role in tumor promotion. Moreover, HIC1, through the direct transcriptional repression of ATOH1 and the Reelin receptors ApoER2 and VLDLR, could play an essential role in normal cerebellar development.
Biochemical and Biophysical Research Communications 09/2013; · 2.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introduction: The tumor suppressor gene HIC1 (Hypermethylated in Cancer 1), which encodes a transcriptional repressor with multiple partners and multiple targets, is epigenetically silenced but not mutated in tumors. HIC1 has broad biological roles during normal development and is implicated in many canonical processes of cancer such as control of cell growth, cell survival upon genotoxic stress, cell migration, and motility. Areas covered: The HIC1 literature herein discussed includes its discovery as a candidate tumor suppressor gene hypermethylated or deleted in many human tumors, animal models establishing it as tumor suppressor gene, its role as a sequence-specific transcriptional repressor recruiting several chromatin regulatory complexes, its cognate target genes, and its functional roles in normal tissues. Finally, this review discusses how its loss of function contributes to the early steps in tumorigenesis. Expert opinion: Given HIC1's ability to direct repressive complexes to sequence-specific binding sites associated with its target genes, its loss results in specific changes in the transcriptional program of the cell. An understanding of this program through identification of HIC1's target genes and their involvement in feedback loops and cell process regulation will yield the ability to leverage this knowledge for therapeutic translation.
Expert opinion on therapeutic targets 04/2013; · 3.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Biologically accurate mouse models of human cancer have become important tools for the study of human disease. The anatomical location of various target organs, such as brain, pancreas, and prostate, makes determination of disease status difficult. Imaging modalities, such as magnetic resonance imaging, can greatly enhance diagnosis, and longitudinal imaging of tumor progression is an important source of experimental data. Even in models where the tumors arise in areas that permit visual determination of tumorigenesis, longitudinal anatomical and functional imaging can enhance the scope of studies by facilitating the assessment of biological alterations, (such as changes in angiogenesis, metabolism, cellular invasion) as well as tissue perfusion and diffusion. One of the challenges in preclinical imaging is the development of infrastructural platforms required for integrating in vivo imaging and therapeutic response data with ex vivo pathological and molecular data using a more systems-based multiscale modeling approach. Further challenges exist in integrating these data for computational modeling to better understand the pathobiology of cancer and to better affect its cure. We review the current applications of preclinical imaging and discuss the implications of applying functional imaging to visualize cancer progression and treatment. Finally, we provide new data from an ongoing preclinical drug study demonstrating how multiscale modeling can lead to a more comprehensive understanding of cancer biology and therapy.
American Journal Of Pathology 12/2012; · 4.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The development of new small molecule-based therapeutic drugs requires accurate quantification of drug bioavailability, biological activity and treatment efficacy. Rapidly measuring these endpoints is often hampered by the lack of efficient assay platforms with high sensitivity and specificity. Using an in vivo model system, we report a simple and sensitive liquid chromatography-tandem mass spectrometry assay to quantify the bioavailability of a recently developed novel cyclin-dependent kinase inhibitor VMY-1-103, a purvalanol B-based analog whose biological activity is enhanced via dansylation. We developed a rapid organic phase extraction technique and validated wide and functional VMY-1-103 distribution in various mouse tissues, consistent with its enhanced potency previously observed in a variety of human cancer cell lines. More importantly, in vivo MRI and single voxel proton MR-Spectroscopy further established that VMY-1-103 inhibited disease progression and affected key metabolites in a mouse model of hedgehog-driven medulloblastoma.
[Show abstract][Hide abstract] ABSTRACT: Studies of the cell secretome have greatly increased in recent years owing to improvements in proteomic platforms, mass spectrometry instrumentation and to the increased interaction between analytical chemists, biologists and clinicians. Several secretome studies have been implemented in different areas of research, leading to the generation of a valuable secretome catalogs. Secreted proteins continue to be an important source of biomarkers and therapeutic target discovery and are equally valuable in the field of microbiology. Several discoveries have been achieved in vitro using cell culture systems, ex vivo using human tissue specimens and in vivo using animal models. In this review, some of the most recent advances in secretome studies and the fields that have benefited the most from this evolving technology are highlighted.
Expert Review of Proteomics 06/2012; 9(3):337-45. · 3.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Diffuse intrinsic pontine glioma (DIPG) is a leading cause of brain tumor-related death in children. DIPG is not surgically resectable, resulting in a paucity of tissue available for molecular studies. As such, tumor biology is poorly understood, and, currently, there are no effective treatments. In the absence of frozen tumor specimens, body fluids--such as cerebrospinal fluid (CSF), serum, and urine--can serve as more readily accessible vehicles for detecting tumor-secreted proteins. We analyzed a total of 76 specimens, including CSF, serum, urine, and normal and tumor brainstem tissue. Protein profiling of CSF from patients with DIPG was generated by mass spectrometry using an LTQ-Orbitrap-XL and database search using the Sequest algorithm. Quantitative and statistical analyses were performed with ProteoIQ and Partek Genomics Suite. A total of 528 unique proteins were identified, 71% of which are known secreted proteins. CSF proteomic analysis revealed selective upregulation of Cyclophillin A (CypA) and dimethylarginase 1 (DDAH1) in DIPG (n = 10), compared with controls (n = 4). Protein expression was further validated with Western blot analysis and immunohistochemical assays using CSF, brain tissue, serum, and urine from DIPG and control specimens. Immunohistochemical staining showed selective upregulation of secreted but not cytosolic CypA and DDAH1 in patients with DIPG. In this study, we present the first comprehensive protein profile of CSF specimens from patients with DIPG to demonstrate selective expression of tumor proteins potentially involved in brainstem gliomagenesis. Detection of secreted CypA and DDAH1 in serum and urine has potential clinical application, with implications for assessing treatment response and detecting tumor recurrence in patients with DIPG.
[Show abstract][Hide abstract] ABSTRACT: The transcriptional repressor HIC1 (Hypermethylated in Cancer 1) is a tumor suppressor gene inactivated in many human cancers including breast carcinomas. In this study, we show that HIC1 is a direct transcriptional repressor of β-2 adrenergic receptor (ADRB2). Through promoter luciferase activity, chromatin immunoprecipitation (ChIP) and sequential ChIP experiments, we demonstrate that ADRB2 is a direct target gene of HIC1, endogenously in WI-38 cells and following HIC1 re-expression in breast cancer cells. Agonist-mediated stimulation of ADRB2 increases the migration and invasion of highly malignant MDA-MB-231 breast cancer cells but these effects are abolished following HIC1 re-expression or specific down-regulation of ADRB2 by siRNA treatment. Our results suggest that early inactivation of HIC1 in breast carcinomas could predispose to stress-induced metastasis through up-regulation of the β-2 adrenergic receptor.
Journal of Biological Chemistry 12/2011; 287(8):5379-89. · 4.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The tumor suppressor gene hypermethylated in cancer 1 (HIC1), which encodes a transcriptional repressor, is epigenetically silenced in many human tumors. Here, we show that ectopic expression of HIC1 in the highly malignant MDA-MB-231 breast cancer cell line severely impairs cell proliferation, migration, and invasion in vitro. In parallel, infection of breast cancer cell lines with a retrovirus expressing HIC1 also induces decreased mRNA and protein expression of the tyrosine kinase receptor EphA2. Moreover, chromatin immunoprecipitation (ChIP) and sequential ChIP experiments demonstrate that endogenous HIC1 proteins are bound, together with the MTA1 corepressor, to the EphA2 promoter in WI38 cells. Taken together, our results identify EphA2 as a new direct target gene of HIC1. Finally, we observe that inactivation of endogenous HIC1 through RNA interference in normal breast epithelial cells results in the up-regulation of EphA2 and is correlated with increased cellular migration. To conclude, our results involve the tumor suppressor HIC1 in the transcriptional regulation of the tyrosine kinase receptor EphA2, whose ligand ephrin-A1 is also a HIC1 target gene. Thus, loss of the regulation of this Eph pathway through HIC1 epigenetic silencing could be an important mechanism in the pathogenesis of epithelial cancers.
Journal of Biological Chemistry 12/2011; 287(8):5366-78. · 4.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aims of this study were to demonstrate the feasibility of centrally collecting and processing high-quality cerebrospinal fluid (CSF) samples for proteomic studies within a multi-center consortium and to identify putative biomarkers for medulloblastoma in CSF. We used 2-DE to investigate the CSF proteome from 33 children with medulloblastoma and compared it against the CSF proteome from 25 age-matched controls. Protein spots were subsequently identified by a combination of in-gel tryptic digestion and MALDI-TOF TOF MS analysis. On average, 160 protein spots were detected by 2-DE and 76 protein spots corresponding to 25 unique proteins were identified using MALDI-TOF. Levels of prostaglandin D2 synthase (PGD2S) were found to be six-fold decreased in the tumor samples versus control samples (p<0.00001). These data were further validated using ELISA. Close examination of PGD2S spots revealed the presence of complex sialylated carbohydrates at residues Asn(78) and Asn(87) . Total PGD2S levels are reduced six-fold in the CSF of children with medulloblastoma most likely representing a host response to the presence of the tumor. In addition, our results demonstrate the feasibility of performing proteomic studies on CSF samples collected from patients at multiple institutions within the consortium setting.
[Show abstract][Hide abstract] ABSTRACT: Anaplastic ependymoma is a malignant glial tumor thought to arise from radial glial cells of the ventricular zone. Because ependymoma is frequently encountered within ventricular spaces, they are prone to leptomeningeal dissemination. Metastatic extracranial ependymoma has been reported, but in the context of progressive intracranial disease. We report on a boy who developed isolated extracranial recurrence of his anaplastic ependymoma, initially at the scalp and later metastases to cervical lymph nodes. The location of tumor recurrence proximate to the surgical site suggested surgical seeding. This case demonstrates an unusual site of recurrence of anaplastic ependymoma and highlights a previously underappreciated surgical complication.
Pediatric Blood & Cancer 02/2011; 56(2):317-8. · 2.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To characterize the relationship between CD34(+) collection efficiency and blood volumes processed in pediatric patients undergoing autologous peripheral blood stem cell (PBSC) collection.
Retrospective 8-year (2001-2009) study of pediatric patients (n = 79) with neuroblastoma and central nervous system (CNS) tumors undergoing first day of autologous PBSC harvest using MNC program on the COBE Spectra (Caridian BCT, Lakewood, CO) was performed. Patients undergoing 0 to 2.9 BV (standard volume), 3 to 6 BV (large volume), and greater than 6 BV (ultra large volume) harvests were evaluated for CD34(+) collection efficiency, diagnosis (neuroblastoma vs. nonneuroblastoma), disease type (primary vs. relapse), mobilization regimen, granulocyte colony stimulating factor (GCSF) dose, and apheresis complications.
CD34(+) collection efficiencies (CE) for neuroblastoma patients were 67%, 50%, and 53% for standard (n = 14), large (n = 9), and ultra large (n = 5) volume harvests, respectively. Similarly, patients with nonneuroblastoma diagnoses had CD34(+) CE of 63%, 55%, and 65% for low (n = 19), large (n = 27), and ultra large (n = 5) volume harvests, respectively. Weight, granulocyte colony stimulating factor (G-CSF) stimulation, type of mobilization, and apheresis complications (normalized by run time) were similar between the standard, large, and ultra large volume groups in patients with either neuroblastoma or nonneuroblastoma diagnoses.
CD34(+) collection efficiency in pediatric autologous PBSC collection on the first day of harvest does not decrease with higher numbers of blood volumes processed in patients with either neuroblastoma or nonneuroblastoma primary disease. These results indirectly indicate bone marrow CD34(+) cell mobilization occurs with longer apheresis procedures in pediatric patients.
Journal of Clinical Apheresis 02/2011; 26(3):131-7. · 2.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The tumor suppressor gene HIC1 (Hypermethylated in Cancer 1) that is epigenetically silenced in many human tumors and is essential for mammalian development encodes a sequence-specific transcriptional repressor. The few genes that have been reported to be directly regulated by HIC1 include ATOH1, FGFBP1, SIRT1, and E2F1. HIC1 is thus involved in the complex regulatory loops modulating p53-dependent and E2F1-dependent cell survival and stress responses. We performed genome-wide expression profiling analyses to identify new HIC1 target genes, using HIC1-deficient U2OS human osteosarcoma cells infected with adenoviruses expressing either HIC1 or GFP as a negative control. These studies identified several putative direct target genes, including CXCR7, a G-protein-coupled receptor recently identified as a scavenger receptor for the chemokine SDF-1/CXCL12. CXCR7 is highly expressed in human breast, lung, and prostate cancers. Using quantitative reverse transcription-PCR analyses, we demonstrated that CXCR7 was repressed in U2OS cells overexpressing HIC1. Inversely, inactivation of endogenous HIC1 by RNA interference in normal human WI38 fibroblasts results in up-regulation of CXCR7 and SIRT1. In silico analyses followed by deletion studies and luciferase reporter assays identified a functional and phylogenetically conserved HIC1-responsive element in the human CXCR7 promoter. Moreover, chromatin immunoprecipitation (ChIP) and ChIP upon ChIP experiments demonstrated that endogenous HIC1 proteins are bound together with the C-terminal binding protein corepressor to the CXCR7 and SIRT1 promoters in WI38 cells. Taken together, our results implicate the tumor suppressor HIC1 in the transcriptional regulation of the chemokine receptor CXCR7, a key player in the promotion of tumorigenesis in a wide variety of cell types.
Journal of Biological Chemistry 07/2009; 284(31):20927-35. · 4.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chemotherapy has taken on a prominent role in the treatment of pediatric low-grade gliomas not amenable to gross total resections; however, there are few proven effective options for children with multiply recurrent tumors. Bevacizumab, a humanized immunoglobulin, monoclonal antibody that inhibits the activity of vascular endothelial growth factor and irinotecan have been used with some success in adults with malignant gliomas.
Ten children with multiply recurrent low-grade gliomas were treated with the combination of bevacizumab and irinotecan. Patients received treatment at a median of 5.2 years of age, range 1.5-11.1 years. The majority had diencephalic tumors, three had neurofibromatosis type 1, and two had disseminated disease at the time of treatment. Nine of 10 patients had progressed after three or greater chemotherapy regimens and one also had received radiation therapy.
Seven patients had an objective neuroradiographic response, which was a complete response in one, partial response in three, and minor response in three. Clinical improvements were noted in seven, including improved visual acuity (2), improved motor function (2), weight gain in four with a diencephalic syndrome, and reversal of psychomotor retardation (3). Dose-limiting toxicities included transient leukoencephalopathy (1) and grade 3 protienuria (1). Response was durable in the majority of patients and six remain on treatment, for up to 22 months.
Multiply recurrent low-grade gliomas in children are responsive to the combination of bevacizumab and irinotecan. The drug combination has been relatively well tolerated, including in patients with neurofibromatosis type 1, and warrants further study.
Pediatric Blood & Cancer 02/2009; 52(7):791-5. · 2.35 Impact Factor