29 results on '"Kamnasaran, Deepak"'
Search Results
2. Progress from clinical trials and emerging non-conventional therapies for the treatment of Medulloblastomas
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Ajeawung, Norbert Fonya, Wang, Hao Yang, and Kamnasaran, Deepak
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- 2013
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3. Viability screen on pediatric low grade glioma cell lines unveils a novel anti-cancer drug of the steroid biosynthesis inhibitor family
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Ajeawung, Norbert Fonya, Maltais, René, Jones, Chris, Poirier, Donald, and Kamnasaran, Deepak
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- 2013
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4. NPAS3 Demonstrates Features of a Tumor Suppressive Role in Driving the Progression of Astrocytomas
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Moreira, Frederico, Kiehl, Tim-Rasmus, So, Kelvin, Ajeawung, Norbert F., Honculada, Carmelita, Gould, Peter, Pieper, Russell O., and Kamnasaran, Deepak
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- 2011
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5. GATA6 Is an Astrocytoma Tumor Suppressor Gene Identified by Gene Trapping of Mouse Glioma Model
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Kamnasaran, Deepak, Qian, Baoping, Hawkins, Cynthia, Stanford, William L., and Guha, Abhijit
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- 2007
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6. Current perspectives on the etiology of agnathia-otocephaly
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Gekas, Jean, Li, Bin, and Kamnasaran, Deepak
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- 2010
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7. Recurrent agnathia–otocephaly caused by DNA replication slippage in PRRX1
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Dasouki, Majed, Andrews, Brian, Parimi, Prabhu, and Kamnasaran, Deepak
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- 2013
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8. Comparative mapping of human Chromosome 14q11.2-q13 genes with mouse homologous gene regions
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Kamnasaran, Deepak, O'Brien, Patricia C.M., Ferguson-Smith, Malcolm A., and Cox, Diane W.
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- 2000
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9. Prenatal diagnosis and identification of heterozygous frameshift mutation in PRRX1 in an infant with agnathia-otocephaly
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Donnelly, Meghan, Todd, Emily, Wheeler, Marsha, Winn, Virginia D, and Kamnasaran, Deepak
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- 2012
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10. Genetic analysis of psychiatric disorders associated with human chromosome 18
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Kamnasaran, Deepak
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- 2003
11. The adjuvant use of lansoprazole, clonazepam and dimenhydrinate for treating intractable hiccups in a patient with gastritis and reflux esophagitis complicated with myocardial infarction: a case report.
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Maximov, Georgi Konstantinov and Kamnasaran, Deepak
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HICCUPS , *MYOCARDIAL infarction , *DRUG side effects , *LANSOPRAZOLE , *DIMENHYDRINATE , *CLONAZEPAM , *FOOD consumption , *THERAPEUTICS - Abstract
Background: Hiccup (Singultus) is a sudden and involuntary contraction of the diaphragm followed by a sharp closure of the epiglottis which results in the production of a specific "hic" sound. Normally, hiccups are treated without intervention. Intractable hiccups occur rarely but are a disturbing symptom underlying other health related disorders. Case presentation: We report the clinical case of a 67-year-old male patient with myocardial infarction accompanied by intractable hiccups during the course of 8 months, and who was non-responsive to chlorpromazine or metoclopramide, and baclofen; drugs routinely used to treat this condition. This sustained hiccup had severely restricted the patient's ability to intake food and sleep. To explore alternative treatments, we investigated the adjuvant administration of lansoprazole, dimenhydrinate and clonazepam in this patient. We discovered that this drug combination was capable of successfully terminating his intractable hiccups, with no further evidence of recurrence. No similar treatment is previously reported for intractable hiccups. We further suggest a hypothesis concerning a potential mechanism on the anti-hiccup effect of dimenhydrinate. Conclusion: We identified that the adjuvant use of lansoprazole, clonazepam and dimenhydrinate was capable of attenuating the symptoms of our patient with intractable hiccups [ABSTRACT FROM AUTHOR]
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- 2013
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12. Preclinical evaluation of dipotassium bisperoxo (picolinato) oxovanadate V for the treatment of pediatric low-grade gliomas.
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Ajeawung, Norbert Fonya, Faure, Robert, Jones, Chris, and Kamnasaran, Deepak
- Abstract
Aim: The treatment of pediatric low-grade gliomas with current treatment modalities still remains ineffective among a subset of patients; hence, justifying the need to further investigate more effective therapies. Dipotassium bisperoxo (picolinato) oxovanadate V (Bpv[pic]), is a derivative of the trace metal vanadium and a potent inhibitor of protein tyrosine phosphatases, which are important mediators of oncogenic and tumor suppressive activities in cancers. In this study, we undertook a preclinical evaluation of the antineoplastic functions of Bpv(pic) in the treatment of pediatric low-grade gliomas.Materials& Methods: We utilized pediatric low-grade glioma cell lines (Res186, Res259 and R286) in a wide variety of cancer assays to determine whether Bpv(pic) can abrogate the neoplastic properties of these cells.Results: Our preclinical evaluation of the antineoplastic properties of Bpv(pic) in pediatric low-grade gliomas reveals a significant dose-dependent decrease in cell viability as a consequence of decreased proliferation and sustained induction of growth arrest and apoptosis. Bpv(pic) significantly decreases cell migration/invasion and anchorage-independent growth in soft agarose. Within cells, Bpv(pic) functions by attenuating CDC25A activity, and by decreasing the expression of multiple protein tyrosine phosphatases, DNA repair genes, microtubule-associated genes, such as PLK1, AURKA and HDAC6, and conversely augmenting the expression of proapoptotic mediators such as BAK, AIFM and CTSL1.Conclusion: Collectively, our data strongly suggest novel evidence of Bpv(pic) being a potent antineoplastic drug and a suitable alternative for the treatment of pediatric low-grade gliomas. [ABSTRACT FROM AUTHOR]- Published
- 2013
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13. Recurrent anencephaly: A case report and examination of the VANGL1 and FOXN1 genes.
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Sergi, Consolato, Gekas, Jean, and Kamnasaran, Deepak
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HUMAN abnormalities ,CRANIOFACIAL abnormalities ,GENETIC testing ,PRENATAL diagnosis ,NEURAL tube defects ,GENETIC mutation ,ANENCEPHALY ,ETIOLOGY of diseases - Abstract
We report a new and rare case of recurrent anencephaly in a family with no other apparent abnormalities. The karyotypes of the family and all affected subjects were normal. Thorough mutational analyses of VANGL1 of chromosome 1p13.1 and FOXN1 of chromosome 17q11-q12, genes that are associated with phenotypes of the anencephaly spectrum, unfortunately did not disclose any DNA variations in an affected fetus of this family. The etiology of recurrent anencephaly in this family is therefore due to mutations in genes yet to be discovered, perhaps of the planar cell polarity pathway, or to possible environmental gestational factors during development. [ABSTRACT FROM AUTHOR]
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- 2013
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14. Holoprosencephaly-Polydactyly (Pseudotrisomy 13) Syndrome: Case Report and Diagnostic Criteria.
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Sergi, Consolato, Gekas, Jean, and Kamnasaran, Deepak
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HOLOPROSENCEPHALY ,POLYDACTYLY ,PRENATAL diagnosis ,GENETIC testing ,HUMAN abnormalities ,PHENOTYPES - Abstract
We report a new case of a fetus with holoprosencephaly-polydactyly syndrome, also known as pseudo-trisomy 13 syndrome, and no other apparent abnormalities except for septal agenesis of the left lung. The fetal karyotype was normal. Mutational analysis of five genes (SHH, SIX3, TGIF, ZIC2, and GLI3), which are major genes associated with holoprosencephaly, did not disclose any mutational findings. We therefore propose that the abnormalities of our fetus support the demarcation of this syndrome as an autonomous phenotype. Specific diagnostic criteria for holoprosencephaly-polydactyly syndrome need to be complemented by the absence of mutations in the major holoprosencephaly genes. [ABSTRACT FROM AUTHOR]
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- 2012
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15. Molecular prenatal diagnosis of a sporadic alobar holoprosencephalic fetus: genotype-phenotype correlations.
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Gekas, Jean, Sergi, Consolato, and Kamnasaran, Deepak
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FETAL brain abnormalities ,HOLOPROSENCEPHALY ,NUCLEOTIDE sequence ,GENETIC mutation ,CYTOGENETICS ,DIAGNOSIS - Abstract
Objective: holoprosencephaly is the most common forebrain malformation syndrome with a multifactorial etiology. Currently, mutations are identified in 5- 10% of non syndromic, non-chromosomal cases in at least 12 genes. We report the molecular prenatal diagnosis of a fetus with alobar holoprosencephaly. Methods: CTG band karyotyping and array CGH genome-wide cytogenetic screenings were done, in conjunction with DNA sequence analyses of the SHH, ZIC2, SIX3 and TGIF genes in search of a molecular etiology and with comparison of findings to prior cases. Results: standard CTG band karyotyping and array CGH genome-wide screening failed to identify plausible chromosome imbalances or structural anomalies. However, extensive sequencing of the genomic DNA from the fetus and both parents on all exon and exon-intron boundaries of the four most commonly mutated genes: SHH, ZIC2, SIX3 and TGIF, identified codon 100 of the sonic hedgehog (SHH) gene having a hotspot for loss-of-function mutations in our case and others. Conclusion: mutations in codon 100 of SHH were discovered in both sporadic and autosomal dominant inherited cases with evidence of variable expressivity and penetrance. Collectively, this study reinforces the complexity of genotype-phenotype correlations in the prenatal diagnosis of holoprosencephalic fetuses. [ABSTRACT FROM AUTHOR]
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- 2012
16. PRENATAL DIAGNOSIS AND MOLECULAR GENETIC STUDIES ON A NEW CASE OF AGNATHIA-OTOCEPHALY.
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Kamnasaran, Deepak, Morin, Françoise, and Gekas, Jean
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GENETIC mutation , *PRENATAL diagnosis , *OBSTETRICAL diagnosis , *ETIOLOGY of diseases , *GENETICS - Abstract
Otocephaly is a severe and lethal malformation. We report a new case of a fetus with Agnathia-Otocephaly, presenting only the facial findings but with otherwise normal organs. The fetal karyotype was normal. We examined the fetal DNA for uniparental disomy of chromo-somes 3 and 4, since the mother is a carrier of a t(3;4) chromosome, but did not identify any evidence. We were also unable to find mutations or possible associations with candidate Otocephalic genes, including OTX2 and PGAP1. These findings suggest that the molecular etiology of Agnathia-Otocephaly is still unknown with a mutation yet to be identified in humans. [ABSTRACT FROM AUTHOR]
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- 2010
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17. Stem cells and models of astrocytomas.
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Kamnasaran, Deepak
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CITATION analysis , *STEM cells , *ASTROCYTOMAS , *GLIOMAS , *TUMORS , *CANCER patients - Abstract
Purpose: To provide a critical assessment of current stemcell based pre-clinical models of astrocytomas (gliomas). Methods: Data were archived from MEDLINE using Boolean formatted keyword queries. Top articles were selected for critical analyses depending on the qualitative assessment of the citation index, novelty of the findings, reputation of the research group and relevance to stem-cell based pre-clinical models of astrocytomas. Results: The emergence of stem-cell based pre-clinical models of gliomas offers advantages for cellular transformation studies over other current in-vitro cell cultured based models. Cells utilized in these stem-cell based preclinical models are easier to transform, with the induced tumours demonstrating very high molecular and pathological recapitulations of astrocytomas that are derived from humans. These stem-cell based models fall into two categories. In the first, synthetic astrocytes can be differentiated from various stem cell sources such as the nervous system and embryos, and utilized in elegant forward genetic strategies to develop novel astrocytoma pre-clinical models. The second category represents a cancer stem cell pre-clinical model. In this model, glioma stem cells exhibit very high pathological recapitulations of the human tumours, and can be very informative to comprehend the basis of radio-chemoresistance among patients. Conclusion: The quest to develop robust pre-clinical models of astrocytomas is on an ongoing basis. The models are of clinical importance for the discovery of effective treatment modalities that can considerably improve the health of patients with this deadly disease. [ABSTRACT FROM AUTHOR]
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- 2009
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18. Characterization and transformation potential of 'Synthetic' astrocytes differentiated from murine embryonic stem cells.
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Kamnasaran, Deepak, Hawkins, Cynthia, and Guha, Abhijit
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- 2008
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19. Expression of GATA6 in the human and mouse central nervous system
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Kamnasaran, Deepak and Guha, Abhijit
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NERVOUS system , *ORGANS (Anatomy) , *NEUROSCIENCES , *IMMUNOCYTOCHEMISTRY - Abstract
Abstract: The mammalian GATA family of transcription factors comprises of 6 members that are involved in diverse roles. The expression profile of GATA6 has been poorly defined in the central nervous system (CNS). In this report, we identify GATA6 expression in the normal mouse and human CNS, using Northern blot analyses, immunohistochemistry (IHC), and immunofluorescence (IF). GATA6 is expressed as a 2.2 kb transcript in the adult mouse brain and several regions of the adult human brain. Furthermore, cellular characterization demonstrates GATA6 nuclear expression in neurons, astrocytes, choroids plexus epithelium, and endothelial cells. [Copyright &y& Elsevier]
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- 2005
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20. Agenesis of the Corpus Callosum: Lessons from Humans and Mice.
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Kamnasaran, Deepak
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CORPUS callosum , *CEREBRAL hemispheres , *HUMAN genetics , *METABOLIC disorders , *MICE , *GENETIC engineering , *TRANSGENIC organisms - Abstract
Background and Purpose: The corpus callosum serves as a bridge to associate fibres between the two cerebral hemispheres. In placental mammals, this commissure provides for higher order neurological advantages. The molecular pathways involved in the development and pathogenesis of accallosal defects are sparse. The article reviews the current progress of studies undertaken to discern the embryological and genetic basis of the development of the corpus callosum. Sources of data: The literature, including from sources such as MEDLINE and OMIM, were subjected to searches for articles reporting findings on corpus callosum development in humans and mice. Principal findings: At least forty-six malformation syndromes and metabolic disorders have been reported in patients with complete agenesis or hypoplasia (dysgenesis) of the corpus callosum. Thirteen of these syndromes have an unknown mode of genetic inheritance, and the remaining syndromes and metabolic disorders exhibit either autosomal or X-linked inheritance among affected families. The use of patients with accallosal defects have identified mutations in at least thirty genes of the human genome, and therefore with roles implicated in the development of the corpus callosum. Patients with chromosome aberrations have been useful in defining regions on chromosomes that contain candidate genes for the development of the corpus callosum. At least eighteen different human chromosomes with numerical and/or structural aberrations have been reported in patients with acallosal defects. The mouse is an excellent model to study the structural and genetic factors that influence the development of the corpus callosum, with many similarities evident in humans. Spontaneous development of acallosal defects has been reported in at least seventeen mouse strains. Furthermore, with the use of Genetically Engineered Mice, a minimum of 15 candidate callosal agenesis genes were modeled in order to provide insightful knowledge of the molecular-structural parameters required for development of the corpus callosum. Of these mice, six had complete true agenesis of the corpus callosum, five had either true agenesis or hypoplasia of the corpus callosum, and four had hypoplasia of the corpus callosum. Conclusions: The molecular mechanisms implicated in the pathogenesis of agenesis or hypoplasia of the corpus callosum are at the verge of discovery, and are challenged by the complexity of many genes involved. Despite these barriers, findings from a complementary human-mouse model system have been helpful in understanding the genetic (molecular) causes of accallosal defects, a fascinating phenotype for over a century. [ABSTRACT FROM AUTHOR]
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- 2005
21. Defining a holoprosencephaly locus on human chromosome 14q13 and characterization of potential candidate genes
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Kamnasaran, Deepak, Chen, Chih-Ping, Devriendt, Koenraad, Mehta, Lakshmi, and Cox, Diane W.
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HOLOPROSENCEPHALY , *PROSENCEPHALON , *CELL nuclei , *HUMAN genetics - Abstract
Abstract: Holoprosencephaly (HPE) is the most common developmental field defect in patterning of the human prosencephalon and associated craniofacial structures. The genetics is complex, with 12 loci defined on 11 chromosomes. We defined a locus for HPE (HPE8) on human chromosome 14q13 between markers D14S49 and AFM205XG5, by mapping deletion intervals of affected subjects with proximal chromosome 14q interstitial cytogenetic deletions. A 35-BAC contig was built by chromosome walking. By annotation of the 2.82-Mb minimal critical region, we identified 28 possible genes. Seven genes were expressed in human fetal brain: NPAS3, SNX6, C14ORF11, C14ORF10, PAX9, NKX2.1, and C14ORF19, the last an apparent gene fragment. Molecular embryology, animal modeling, and human mutation studies were reported elsewhere for PAX9 and NKX2.1. We focused on three genes, SNX6, NPAS3, and C14ORF11, as potential candidates for HPE. Genomic structure, human expression patterns, protein cellular localization, and embryonic expression patterns of orthologous murine genes were determined, showing that the three genes have properties similar to those of known HPE genes. [Copyright &y& Elsevier]
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- 2005
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22. Rearrangement in the PITX2 and MIPOL1 genes in a patient with a t(4;14) chromosome.
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Kamnasaran, Deepak, O'Brien, Patricia C, Zackai, Elaine H, Muenke, Maximilian, Ferguson-Smith, Malcolm A, and Cox, Diane W
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CENTRAL nervous system diseases , *CHROMOSOMES , *CHROMOSOMAL translocation - Abstract
We report the molecular characterization of a patient with mild craniofacial and acallosal central nervous system midline defects and a t(4;14)(q25)(q13) chromosome. With the use of flow sorted chromosomes, the translocation breakpoint junction was defined within a 100 kb region with markers mapping to chromosomes 4q25 and 14q13. Analysis of genomic sequences demonstrated that the breakpoint junction at 14q13 was within the third intron of the 5' untranslated region of the MIPOL1 gene (GI: 22048098). On chromosome 4q25, two breakpoint junctions were found. One was about 47 kb distal to the 5' end of a putative gene (GI: 8923996) with unknown function but with partial similarity to kinases, and a second breakpoint was within the 3' end of the PITX2 gene (GI: 21361182) that resulted in the deletion of exons 6 and 7 of this gene. We also searched for microdeletions in a panel of candidate genes mapping within 2 Mb of the translocation breakpoint junction on chromosomes 4 and 14, however, no evidence for deletions or rearrangements was found. The finding of two breaks on chromosome 4q25 suggests a complex microrearrangement, such as an inversion, in addition to a translocation in this patient. [ABSTRACT FROM AUTHOR]
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- 2003
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23. Epigenetic inheritance associated with human chromosome 14.
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Kamnasaran, Deepak
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EPIGENESIS , *HUMAN chromosomes - Abstract
Within the last decade, there has been sufficient evidence to support the association of epigenetic inheritance or genomic imprinting on human chromosome 14. This has been achieved with studies of imprinting on both human chromosome 14 and mouse chromosome 12, which has the largest homology to human chromosome 14. Initial studies with mouse chromosome 12 aberrations suggested that specific phenotypes due to genomic imprinting were confined to the maternal or paternal mouse chromosome 12, depending on the parent from which the chromosome was inherited. Such findings were later supplemented with human chromosome 14 aberrations that had provided evidence for imprinted intervals on this chromosome, and possibly 2 syndromes associated with a maternal or paternal uniparental disomy affecting chromosome 14. The recent discovery of 2 imprinted genes on human chromosome 14 and mouse chromosome 12 has confirmed genomic imprinting on these chromosomes. These findings will refine our understanding of the clinical consequences of human chromosome 14 aberrations and of the causes of the disease phenotype associated with defective imprinted genes. This article reviews evidence in mice and humans, and the clinical implications for genomic imprinting associated with human chromosome 14. [ABSTRACT FROM AUTHOR]
- Published
- 2001
24. Translational applications of microRNA genes in medulloblastomas.
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Ajeawung, Norbert F., Bin Li, and Kamnasaran, Deepak
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MEDULLOBLASTOMA , *RNA , *CEREBELLAR tumors , *BRAIN physiology , *PROGNOSIS , *GENE expression , *GENETIC regulation , *GENES , *PATHOGENIC microorganisms - Abstract
Purpose: To provide a critical assessment of the clinical translational applications of microRNA (miRNA) genes in medulloblastomas. Methods: Data were obtained from MEDLINE using Boolean-formatted keyword queries. Top articles were selected for critical analyses - depending on the novelty of findings, qualitative assessment of the citation index and relevance to the diagnosis, prognosis and therapeutic targeting of medulloblastomas. Results: MiRNAs, non-protein-coding RNA molecules, negatively regulate gene expression in a sequence-specific manner during biological processes. In the past few years, miRNA genes have emerged as key regulators of not only molecular events involved in normal brain development and function but also in the molecular pathogenesis of medulloblastomas. In this manner, microRNA genes are identified with functional roles as oncogenes and tumor suppressor genes. At least four miRNAs have proven useful in improving the molecular classification of medulloblastomas, and eight others have shown potential in predicting patients' overall prognosis. Moreover, more than 10 miRNA genes can be potentially utilized in therapies against medulloblastomas, using nine recent methods of targetting miRNAs. Conclusion: The quest to identify miRNA genes that are of biological significance in medulloblastomas is on an ongoing venture. Most importantly, these miRNAs have been shown to be of clinical importance for improving the accuracy of diagnosis and prognosis and even developing therapies that can significantly improve patients' overall survival from this deadly disease. [ABSTRACT FROM AUTHOR]
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- 2010
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25. Advances in Molecular Targets for the Treatment of Medulloblastomas.
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Ajeawung, Norbert F., Wang, Hao Y., Gould, Peter, and Kamnasaran, Deepak
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MOLECULAR biology , *TARGETED drug delivery , *MEDULLOBLASTOMA , *CELLULAR signal transduction , *CANCER prognosis , *SPONTANEOUS cancer regression , *CLINICAL trials , *THERAPEUTICS - Abstract
Purpose: To present an assortment of molecular targets evident from a variety of signal transduction pathways and downstream effectors, which may have clinical relevance for the treatment of medulloblastomas. Source: Data were archived from MEDLINE, using Boolean-formatted queries on the keywords including: medulloblastoma, pathology, prognosis, classification, tumor regression, inhibition, therapy, clinical trial, therapeutic agent, drug, molecular inhibitor, and signalling pathway. Only the most reputable articles were selected for critical analyses based on the qualitative assessment of the citation index, novelty of the findings and relevance to prospective novel ways of targeted therapies for medulloblastomas. Principal findings: Medulloblastomas are highly aggressive embryonal tumors of the cerebellum, akin to primitive neuroectodermal tumors elsewhere in the brain. Current treatments for medulloblastomas which include a combination of surgery, chemotherapy and radiation, remain challenging especially, for younger patients; however, advances in understanding regulatory pathways in medulloblastomas are crucial to develop more effective therapeutic targets. Evidence showing several molecular and pharmacological targets within key signalling pathways, such as HEDGEHOG, WNT, NOTCH, Receptor Tyrosine Kinase (ERB, IGF-IR, c-MET, PDGF, Estrogen, p75NTR), their downstream effectors like PI3K/AKT, c-MYC and STAT3, and as well as other targets such as telomerase and cytoskeletal elements, is summarized. All molecular and pharmacological targets have pivotal roles in the pathogenesis of medulloblastomas. Most importantly, these pathways can be effectively pharmacologically targeted to regress the growth of medulloblastomas. Pre-clinical studies were routinely undertaken with a variety of human and murine cell lines and as well as murine models of medulloblastomas. Thus far, two drugs which target the NOTCH and HEDGEHOG signalling have completed Phase I clinical trials, but with evidence of low ecacies; hence, reinforcing the importance of continuing investigations in search of new therapeutic agents and targets. Conclusion: Novel therapies, based on better understanding key biological pathways in medulloblastomas, hold promise for improved treatments in due course among patients with medulloblastomas. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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26. Investigation of Targetin, a Microtubule Binding Agent which Regresses the Growth of Pediatric High and Low Grade Gliomas.
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Ajeawung NF, Joshi HC, and Kamnasaran D
- Abstract
Background: Pediatric gliomas, the most common solid childhood neoplasm, manifest unique molecular signatures that distinguish them from adult gliomas. Unfortunately, most studies have focused on adult gliomas and extrapolate the findings to treat pediatric gliomas. In this study, we assessed the efficacy of Targetin, a folate conjugated analogue of Noscapine, on the treatment of pediatric low and high grade gliomas., Method: An assortment of standard cancer assays were used with different drug doses and experimental durations., Results: We found that pediatric glioma cells are more susceptible to lower doses of Targetin than parental Noscapine. Targetin functions by disrupting the microtubule network, and can likewise perturb DNA synthesis, delay the cellular transition within the S and G2M cell cycle phases, diminish anchorage independent growth and the migratory/invasiveness of pediatric glioma cells. Moreover, Targetin impairs the expression of several regulators of cancer progression belonging to prominent signalling pathways in pediatric gliomas; including Platelet Derived Growth Factor alpha and some members of the Mitogen Activated Protein Kinase cascade., Conclusion: Targetin has an excellent anti-neoplastic profile and functions to modulate the expression of several genes belonging to key cancer progression pathways in pediatric gliomas. Collectively, findings from this study highlight the usefulness of Targetin for the treatment of pediatric high and low grade gliomas.
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- 2013
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27. In-Vitro and Ex-Vivo Investigations of the Microtubule Binding Drug Targetin on Angiogenesis.
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Ajeawung NF, Mononen L, Thorn A, Pin AL, Joshi HC, Huot J, and Kamnasaran D
- Abstract
Background: Intervention aimed at disrupting or inhibiting newly formed vascular network is highly desired to attenuate the progression of angiogenesis-dependent diseases. In cancer, this is tightly associated with the generation of VEGF by hypoxia inducible factor-1α following its activation by hypoxia. In light of the multiple cellular roles played by microtubules and their involvement in the processing of the hypoxia inducible factor-1α transcript, modulation of microtubule dynamics is emerging as a logical approach to suppress tumor reliance on angiogenesis. Targetin is a novel noscapinoid that interferes with microtubule dynamicity and inhibits the growth of cell lines from many types of cancers., Methods and Results: Utilizing in-vitro and ex-vivo angiogenic models, we discovered the vascular disrupting and anti-angiogenic properties of Targetin. Targetin disrupted pre-assembled capillary-like networks of human endothelial cells by severing cell-cell junctions, inhibiting endothelial cell proliferation and metabolic activity in the presence and absence of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Furthermore, we show that Targetin significantly inhibits the formation of neovasculature network sprouting from rat aortic explants stimulated with proangiogenic stimuli, namely VEGF or bFGF., Conclusion: We conclude that Targetin is a potential clinically promising anti-angiogenic agent for the treatment of many diseases including cancers.
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- 2013
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28. Human schwannomas express activated platelet-derived growth factor receptors and c-kit and are growth inhibited by Gleevec (Imatinib Mesylate).
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Mukherjee J, Kamnasaran D, Balasubramaniam A, Radovanovic I, Zadeh G, Kiehl TR, and Guha A
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- Apoptosis, Benzamides, Blotting, Western, Cell Cycle, Cell Line, Tumor, Humans, Imatinib Mesylate, Magnetic Resonance Imaging, Neurilemmoma pathology, Polymerase Chain Reaction, Antineoplastic Agents pharmacology, Cell Division drug effects, Neurilemmoma metabolism, Piperazines pharmacology, Proto-Oncogene Proteins c-kit metabolism, Pyrimidines pharmacology, Receptors, Platelet-Derived Growth Factor metabolism
- Abstract
Schwannomas, although benign, can be fatal or give rise to significant morbidity due to an unpredictable growth rate. They can reoccur after surgery or radiation, current treatments each with significant inherent risks. These risks are further amplified in neurofibromatosis type 2 (NF2), a germ line predisposition syndrome characterized by multiple schwannomas, underlying the need for biological targeted therapies. Gleevec (STI571, imatinib mesylate), in addition to the bcr-abl oncogene in chronic myelogenous leukemia, inhibits c-kit and platelet-derived growth factor receptor (PDGFR) signaling, thereby expanding its use to several malignant and benign human diseases. In the present study, we show that human sporadic and NF2-associated schwannomas have increased expression along with activation of PDGFR-alpha, PDGFR-beta, and c-kit receptors, compared with normal or traumatic nerve. Using the human NF2-null HEI-193 schwannoma cell line, Gleevec inhibited schwannoma viability, proliferation, and anchorage-independent growth, as well as induced apoptosis in a dose-dependent manner (IC(50) 5-10 micromol/L). These antitumorigenic effects were correlated to inhibition of PDGFR-alpha, PDGFR-beta, and c-kit activation/phosphorylation and major downstream signaling pathways. Lack of robust xenograft or transgenic models of schwannomas prevents extension of these studies in vivo. However, the established long track record and tolerable toxicity of Gleevec already in clinical use and our preclinical data lead us to propose that Gleevec should be evaluated in human schwannomas with shown progressive growth.
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- 2009
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29. Pathological and molecular progression of astrocytomas in a GFAP:12 V-Ha-Ras mouse astrocytoma model.
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Shannon P, Sabha N, Lau N, Kamnasaran D, Gutmann DH, and Guha A
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- Animals, Astrocytes pathology, Astrocytoma metabolism, Cells, Cultured, Disease Models, Animal, Disease Progression, Gene Expression, Growth Substances metabolism, Hyperplasia, Mice, Mice, Inbred ICR, Mutation, Nerve Tissue Proteins deficiency, Tumor Suppressor Protein p53 genetics, Astrocytoma genetics, Astrocytoma pathology, Central Nervous System Neoplasms genetics, Central Nervous System Neoplasms pathology, Genes, ras, Glial Fibrillary Acidic Protein genetics, Mice, Transgenic genetics
- Abstract
We previously characterized a genetically engineered mouse astrocytoma model with embryonic astrocyte-specific, activated (12)V-Ha-RAS (GFAP-RAS) transgenesis. The GFAP-RAS line Ras-B8 appears normal at birth, but 50% of mice die by 4 months from low- and high-grade astrocytomas. We examined the development and progression of astrocytomas in the Ras-B8 genetically engineered mouse. At embryonic day 16.5 (E16.5), there were no pathological differences compared to control littermates, aside from transgene expression. Diffuse astroglial hyperplasia was the first distinguishing feature in the 1-week-old Ras-B8 mice; however, these astrocytes were not transformed in vitro or in vivo. From 3 to 8 weeks the incidence of low-grade astrocytomas progressively increased with 85% of 12-week-old mice harboring low- or high-grade astrocytomas, the latter characterized by increased proliferation, nuclear atypia, and angiogenesis. Tp 53 mutations were detected in both astrocytoma grades, with high-grade astrocytomas expressing elevated levels of epidermal growth factor receptor and vascular endothelial growth factor, plus decreased levels of PTEN and p16, similar to human astrocytomas. We postulate that expression of (12)V-Ha-RAS in astroglial precursors induces astroglial hyperplasia, but transformation and subsequent progression requires additional molecular alterations resulting from aberrant activated p21-RAS. Of interest, many of these acquired alterations occur in human astrocytomas, further validating GFAP-RAS as a useful model for studying astrocytoma development and progression.
- Published
- 2005
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