Publications (12)57.23 Total impact
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Article: Aneuploidy, Oncogene Amplification, and Epithelial to Mesenchymal Transition Define Spontaneous Transformation of Murine Epithelial Cells.
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ABSTRACT: Human epithelial cancers are defined by a recurrent distribution of specific chromosomal aneuploidies, a trait less typical for murine cancer models induced by an oncogenic stimulus. After prolonged culture, mouse epithelial cells spontaneously immortalize, transform, and become tumorigenic. We assessed genome and transcriptome alterations in cultures derived from bladder and kidney utilizing SKY, array CGH, FISH, and gene expression profiling. The results show widespread aneuploidy, yet a recurrent and tissue specific distribution of genomic imbalances, just as in human cancers. Losses of chromosome 4 and gains of chromosome 15 are common and occur early during the transformation process. Global gene expression profiling revealed early and significant transcriptional deregulation. Chromosomal aneuploidy resulted in expression changes of resident genes, and consequently in a massive deregulation of the cellular transcriptome. Pathway interrogation of expression changes during the sequential steps of transformation revealed enrichment of genes associated with DNA repair, centrosome regulation, stem cell characteristics, and aneuploidy. Genes that modulate the epithelial to mesenchymal transition and genes that define the chromosomal instability phenotype played a dominant role, and were changed in a directionality consistent with loss of cell adhesion, invasiveness and proliferation. Comparison with gene expression changes during human bladder and kidney tumorigenesis revealed remarkable overlap with changes observed in the spontaneously transformed murine cultures. Therefore, our novel mouse models faithfully recapitulate the sequence of genomic and transcriptomic events that define human tumorigenesis, hence validating them for both basic and preclinical research.Carcinogenesis 04/2013; · 5.70 Impact Factor -
Article: Spontaneous transformation of murine epithelial cells requires the early acquisition of specific chromosomal aneuploidies and genomic imbalances.
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ABSTRACT: Human carcinomas are defined by recurrent chromosomal aneuploidies, which result in a tissue-specific distribution of genomic imbalances. In order to develop models for these genome mutations and to determine their role in tumorigenesis, we generated 45 spontaneously transformed murine cell lines from normal epithelial cells derived from bladder, cervix, colon, kidney, lung, and mammary gland. Phenotypic changes, chromosomal aberrations, centrosome number, and telomerase activity were assayed in control uncultured cells and in three subsequent stages of transformation. Supernumerary centrosomes, binucleate cells, and tetraploidy were observed as early as 48 hr after explantation. In addition, telomerase activity increased throughout progression. Live-cell imaging revealed that failure of cytokinesis, not cell fusion, promoted genome duplication. Spectral karyotyping demonstrated that aneuploidy preceded immortalization, consisting predominantly of whole chromosome losses (4, 9, 12, 13, 16, and Y) and gains (1, 10, 15, and 19). After transformation, focal amplifications of the oncogenes Myc and Mdm2 were frequently detected. Fifty percent of the transformed lines resulted in tumors on injection into immunocompromised mice. The phenotypic and genomic alterations observed in spontaneously transformed murine epithelial cells recapitulated the aberration pattern observed during human carcinogenesis. The dominant aberration of these cell lines was the presence of specific chromosomal aneuploidies. We propose that our newly derived cancer models will be useful tools to dissect the sequential steps of genome mutations during malignant transformation, and also to identify cancer-specific genes, signaling pathways, and the role of chromosomal instability in this process.Genes Chromosomes and Cancer 12/2011; 51(4):353-74. · 3.31 Impact Factor -
Article: UOK 262 cell line, fumarate hydratase deficient (FH-/FH-) hereditary leiomyomatosis renal cell carcinoma: in vitro and in vivo model of an aberrant energy metabolic pathway in human cancer.
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ABSTRACT: Energy deregulation and abnormalities of tumor cell metabolism are critical issues in understanding cancer. Hereditary leiomyomatosis renal cell carcinoma (HLRCC) is an aggressive form of RCC characterized by germline mutation of the Krebs cycle enzyme fumarate hydratase (FH), and one known to be highly metastatic and unusually lethal. There is considerable utility in establishing preclinical cell and xenograft models for study of disorders of energy metabolism, as well as in development of new therapeutic approaches targeting of tricarboxylic acid (TCA) cycle enzyme-deficient human cancers. Here we describe a new immortalized cell line, UOK 262, derived from a patient having aggressive HLRCC-associated recurring kidney cancer. We investigated gene expression, chromosome profiles, efflux bioenergetic analysis, mitochondrial ultrastructure, FH catabolic activity, invasiveness, and optimal glucose requirements for in vitro growth. UOK 262 cells have an isochromosome 1q recurring chromosome abnormality, i(1)(q10), and exhibit compromised oxidative phosphorylation and in vitro dependence on anaerobic glycolysis consistent with the clinical manifestation of HLRCC. The cells also display glucose-dependent growth, an elevated rate of lactate efflux, and overexpression of the glucose transporter GLUT1 and of lactate dehydrogenase A (LDHA). Mutant FH protein was present primarily in edematous mitochondria, but with catalytic activity nearly undetectable. UOK 262 xenografts retain the characteristics of HLRCC histopathology. Our findings indicate that the severe compromise of oxidative phosphorylation and rapid glycolytic flux in UOK 262 are an essential feature of this TCA cycle enzyme-deficient form of kidney cancer. This tumor model is the embodiment of the Warburg effect. UOK 262 provides a unique in vitro and in vivo preclinical model for studying the bioenergetics of the Warburg effect in human cancer.Cancer genetics and cytogenetics 01/2010; 196(1):45-55. · 1.54 Impact Factor -
Article: Definitive molecular cytogenetic characterization of 15 colorectal cancer cell lines.
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ABSTRACT: In defining the genetic profiles in cancer, cytogenetically aberrant cell lines derived from primary tumors are important tools for the study of carcinogenesis. Here, we present the results of a comprehensive investigation of 15 established colorectal cancer cell lines using spectral karyotyping (SKY), fluorescence in situ hybridization, and comparative genomic hybridization (CGH). Detailed karyotypic analysis by SKY on five of the lines (P53HCT116, T84, NCI-H508, NCI-H716, and SK-CO-1) is described here for the first time. The five lines with karyotypes in the diploid range and that are characterized by defects in DNA mismatch repair had a mean of 4.8 chromosomal abnormalities per line, whereas the 10 aneuploid lines exhibited complex karyotypes and a mean of 30 chromosomal abnormalities. Of the 150 clonal translocations, only eight were balanced and none were recurrent among the lines. We also reviewed the karyotypes of 345 cases of adenocarcinoma of the large intestine listed in the Mitelman Database of Chromosome Aberrations in Cancer. The types of abnormalities observed in the cell lines reflected those seen in primary tumors: there were no recurrent translocations in either tumors or cell lines; isochromosomes were the most common recurrent abnormalities; and breakpoints occurred most frequently at the centromeric/pericentromeric and telomere regions. Of the genomic imbalances detected by array CGH, 87% correlated with chromosome aberrations observed in the SKY studies. The fact that chromosome abnormalities predominantly result in copy number changes rather than specific chromosome or gene fusions suggests that this may be the major mechanism leading to carcinogenesis in colorectal cancer.Genes Chromosomes and Cancer 11/2009; 49(3):204-23. · 3.31 Impact Factor -
Article: Integrative genomics reveals mechanisms of copy number alterations responsible for transcriptional deregulation in colorectal cancer.
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ABSTRACT: To evaluate the mechanisms and consequences of chromosomal aberrations in colorectal cancer (CRC), we used a combination of spectral karyotyping, array comparative genomic hybridization (aCGH), and array-based global gene expression profiling on 31 primary carcinomas and 15 established cell lines. Importantly, aCGH showed that the genomic profiles of primary tumors are recapitulated in the cell lines. We revealed a preponderance of chromosome breakpoints at sites of copy number variants (CNVs) in the CRC cell lines, a novel mechanism of DNA breakage in cancer. The integration of gene expression and aCGH led to the identification of 157 genes localized within high-level copy number changes whose transcriptional deregulation was significantly affected across all of the samples, thereby suggesting that these genes play a functional role in CRC. Genomic amplification at 8q24 was the most recurrent event and led to the overexpression of MYC and FAM84B. Copy number dependent gene expression resulted in deregulation of known cancer genes such as APC, FGFR2, and ERBB2. The identification of only 36 genes whose localization near a breakpoint could account for their observed deregulated expression demonstrates that the major mechanism for transcriptional deregulation in CRC is genomic copy number changes resulting from chromosomal aberrations.Genes Chromosomes and Cancer 09/2009; 48(11):1002-17. · 3.31 Impact Factor -
Article: The UOK 257 cell line: a novel model for studies of the human Birt-Hogg-Dubé gene pathway.
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ABSTRACT: The establishment, characterization, and tumorigenicity of a new epithelial cell line (UOK 257) derived from human renal carcinoma of an individual with Birt-Hogg-Dubé (BHD) syndrome are reported. Unlike other established renal tumor cell lines from sporadic renal cell carcinoma, this is the first established renal tumor cell line of BHD, an inheritable neoplastic syndrome. The isolated tumor cells display loss of contact inhibition in vitro, and produce subcutaneous tumors in mouse xenografts. Histopathologic, ultrastructural, and cytogenetic characterizations of the established tumor cells are reported. Cytogenetic analysis using spectral karyotyping on UOK 257 cells revealed 17p loss and a near-triploid and aneuploid karyotype with multiple fluorescence in situ hybridization analysis using a locus-specific gene probe for MYC. The result demonstrates that the established tumor cells consist of two cell populations, one containing four and one containing five copies of the MYC oncogene.Cancer Genetics and Cytogenetics 02/2008; 180(2):100-9. · 1.39 Impact Factor -
Article: A sequence-based survey of the complex structural organization of tumor genomes.
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ABSTRACT: The genomes of many epithelial tumors exhibit extensive chromosomal rearrangements. All classes of genome rearrangements can be identified using end sequencing profiling, which relies on paired-end sequencing of cloned tumor genomes. In the present study brain, breast, ovary, and prostate tumors, along with three breast cancer cell lines, were surveyed using end sequencing profiling, yielding the largest available collection of sequence-ready tumor genome breakpoints and providing evidence that some rearrangements may be recurrent. Sequencing and fluorescence in situ hybridization confirmed translocations and complex tumor genome structures that include co-amplification and packaging of disparate genomic loci with associated molecular heterogeneity. Comparison of the tumor genomes suggests recurrent rearrangements. Some are likely to be novel structural polymorphisms, whereas others may be bona fide somatic rearrangements. A recurrent fusion transcript in breast tumors and a constitutional fusion transcript resulting from a segmental duplication were identified. Analysis of end sequences for single nucleotide polymorphisms revealed candidate somatic mutations and an elevated rate of novel single nucleotide polymorphisms in an ovarian tumor. These results suggest that the genomes of many epithelial tumors may be far more dynamic and complex than was previously appreciated and that genomic fusions, including fusion transcripts and proteins, may be common, possibly yielding tumor-specific biomarkers and therapeutic targets.Genome biology 02/2008; 9(3):R59. · 6.63 Impact Factor -
Article: A virus causes cancer by inducing massive chromosomal instability through cell fusion.
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ABSTRACT: Chromosomal instability (CIN) underlies malignant properties of many solid cancers and their ability to escape therapy, and it might itself cause cancer [1, 2]. CIN is sustained by deficiencies in proteins, such as the tumor suppressor p53 [3-5], that police genome integrity, but the primary cause of CIN in sporadic cancers remains uncertain [6, 7]. The primary suspects are mutations that deregulate telomere maintenance, or mitosis, yet such mutations have not been identified in the majority of sporadic cancers [6]. Alternatively, CIN could be caused by a transient event that destabilizes the genome without permanently affecting mechanisms of mitosis or proliferation [5, 8]. Here, we show that an otherwise harmless virus rapidly causes massive chromosomal instability by fusing cells whose cell cycle is deregulated by oncogenes. This synergy between fusion and oncogenes "randomizes" normal diploid human fibroblasts so extensively that each analyzed cell has a unique karyotype, and some produce aggressive, highly aneuploid, heterogeneous, and transplantable epithelial cancers in mice. Because many viruses are fusogenic, this study suggests that viruses, including those that have not been linked to carcinogenesis, can cause chromosomal instability and, consequently, cancer by fusing cells.Current Biology 04/2007; 17(5):431-7. · 9.65 Impact Factor -
Article: Spectral karyotyping demonstrates genetically unstable skin-homing T lymphocytes in cutaneous T-cell lymphoma.
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ABSTRACT: We initially established cell lines from skin biopsies from four patients (MF8, MF18, MF19 and MF31) in early stages of cutaneous T-cell lymphoma (CTCL) in 1999. After 3 weeks of culture, skin-homing T lymphocytes were stimulated with phytohaemagglutinin. Metaphase spreads were analysed using spectral karyotyping (SKY), a molecular cytogenetic technique. MF18 and MF19 had predominantly normal karyotypes. MF8 had recurrent numerical aberrations resulting in two T lymphocyte clones: one with trisomy 21 (12/20 cells) and the other with monosomy chromosome 22 (3/20 cells). MF8 also exhibited a clonal deletion, del(5)(p15.1), as well as multiple non-clonal structural aberrations. MF31 had a clonal deletion, del(17)(p12) and other non-clonal deletions involving chromosomes 2, 5, 10, 11. MF18 had a single abnormal cell that contained two reciprocal translocations t(1;2)(q32;p21) and t(4;10)(p15.2;q24). In 2001, three of the original patients had new skin biopsies taken and cell lines were established. SKY analysis revealed the continued presence of a T-cell clone in MF8 with trisomy 21 (4/20 cells). Additionally, a new clone was seen with a del(18)(p11.2) (17/20 cells). MF31 had only one aberrant cell with a del(17)(p12). MF18 had a clonal deletion, [del(1)(p36.1) in 3/20 cells] and non-clonal aberrations involving chromosomes 3, 4, 5, 6, 12, 13, 17 and 18. Thus, three of four patients continued to show numerous numerical and structural aberrations, both clonal and non-clonal, with only MF8 having a recurring T lymphocyte clone (+21). Our findings demonstrate high genetic instability among skin-homing T lymphocytes even in early stages of CTCL. We did not see genetic instability or evidence of clones in cell lines from a patient with atopic dermatitis and one with psoriasis.Experimental Dermatology 03/2007; 16(2):98-103. · 3.54 Impact Factor -
Article: Spectral karyotyping analysis of human and mouse chromosomes
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ABSTRACT: Classical banding methods provide basic information about the identities and structures of chromosomes on the basis of their unique banding patterns. Spectral karyotyping (SKY), and the related multiplex fluorescence in situ hybridization (M-FISH), are chromosome-specific multicolor FISH techniques that augment cytogenetic evaluations of malignant disease by providing additional information and improved characterization of aberrant chromosomes that contain DNA sequences not identifiable using conventional banding methods. SKY is based on cohybridization of combinatorially labeled chromosome-painting probes with unique fluorochrome signatures onto human or mouse metaphase chromosome preparations. Image acquisition and analysis use a specialized imaging system, combining Sagnac interferometer and CCD camera images to reconstruct spectral information at each pixel. Here we present a protocol for SKY analysis using commercially available SkyPaint probes, including procedures for metaphase chromosome preparation, slide pretreatment and probe hybridization and detection. SKY analysis requires approximately 6 d.Nature Protocols 01/2007; 1(6):3129-3142. · 9.92 Impact Factor -
Article: Accumulated chromosomal instability in murine bone marrow mesenchymal stem cells leads to malignant transformation.
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ABSTRACT: Despite recent emerging evidence suggesting that cancer stem cells subsist in a variety of tumors, it is not yet fully elucidated whether postnatal stem cells are directly involved in tumorigenesis. We used murine bone marrow-derived mesenchymal stem cells (BMMSCs) as a model to test a hypothesis that tumorigenesis may originate from spontaneous mutation of stem cells. In this study, we demonstrated that murine BMMSCs, after numerous passages, obtained unlimited population doublings and proceeded to a malignant transformation state, resulting in fibrosarcoma formation in vivo. Transformed BMMSCs colonized to multiple organs when delivered systemically through the tail vein. Fibrosarcoma cells formed by transformed BMMSCs contained cancer progenitors, which were capable of generating colony clusters in vitro and fibrosarcoma in vivo by the second administration. The mechanism by which BMMSCs transformed to malignant cells was associated with accumulated chromosomal abnormalities, gradual elevation in telomerase activity, and increased c-myc expression. Moreover, BMMSCs and their transformed counterpart, fibrosarcoma-forming cells, demonstrated different sensitivity to anti-cancer drugs. BMMSCs/fibrosarcoma transformation system may provide an ideal system to elucidate the mechanism of how stem cells become cancer cells and to screen anti-sarcoma drugs.Stem Cells 05/2006; 24(4):1095-103. · 7.78 Impact Factor -
Article: Novel translocation in acute megakaryoblastic leukemia (AML-M7).
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ABSTRACT: The authors report a unique translocation in a patient with M7 acute myeloid leukemia and review the literature. A 22-month-old girl without Down syndrome was diagnosed with acute myeloid leukemia, subtype M7 (AML-M7), and died with relapsed disease following bone marrow transplantation. Tumor cells were evaluated using cytogenetics (including spectral karyotyping), immunohistochemistry, and flow cytometry. The patient was found to have a previously unreported complex translocation as follows: 50,XX,der(1)t(1;5)(p36?.1;p15?.1),del(5)(p15?.1), +6,+der(6;7)(?;?),der(7)t(6;7)(?;p22)[2],der(9)t(6;9) (?;p21)t(9;14)(q34;q11.2-q13),+10,t(12;16)(p13;q24),-14[2], del(14)(q13)[2],+der(19)t(1;19)(?;p13.3),+22[cp 4]. AML-M7 in non-Down syndrome patients is a rare disease that requires improved prognostic markers.Journal of Pediatric Hematology/Oncology 06/2003; 25(5):396-402. · 1.16 Impact Factor
Top co-authors
Top Journals
Institutions
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2007–2011
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National Cancer Institute (USA)
- Genetics Branch
Bethesda, MD, USA -
National Institutes of Health
- Branch of Genetics
Bethesda, MD, USA
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