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Torben F Orntoft

Publications and source records attributed to Torben F Orntoft.

At least 19 recordsLinked to original sources
PubMed2006

Germline fumarate hydratase mutations in patients with ovarian mucinous cystadenoma.

Germline mutations in the fumarate hydratase (FH) gene were recently shown to predispose to the dominantly inherited syndrome, hereditary leiomyomatosis and renal cell cancer (HLRCC). HLRCC is characterized by benign leiomyomas of the skin and the uterus, renal cell carcinoma, and uterine leiomyosarcoma. The aim of this study was to identify new families with FH mutations, and to further examine the tumor spectrum associated with FH mutations. FH germline mutations were screened from 89 patients with RCC, skin leiomyomas or ovarian tumors. Subsequently, 13 ovarian and 48 bladder carcinomas were analyzed for somatic FH mutations. Two patients diagnosed with ovarian mucinous cystadenoma (two out of 33, 6%) were found to be FH germline mutation carriers. One of the changes was a novel mutation (Ala231Thr) and the other one (435insAAA) was previously described in FH deficiency families. These results suggest that benign ovarian tumors may be associated with HLRCC.

Carcinoma, Renal Cell↗
PubMed2006

A truncating mutation of HDAC2 in human cancers confers resistance to histone deacetylase inhibition.

Disruption of histone acetylation patterns is a common feature of cancer cells, but very little is known about its genetic basis. We have identified truncating mutations in one of the primary human histone deacetylases, HDAC2, in sporadic carcinomas with microsatellite instability and in tumors arising in individuals with hereditary nonpolyposis colorectal cancer syndrome. The presence of the HDAC2 frameshift mutation causes a loss of HDAC2 protein expression and enzymatic activity and renders these cells more resistant to the usual antiproliferative and proapoptotic effects of histone deacetylase inhibitors. As such drugs may serve as therapeutic agents for cancer, our findings support the use of HDAC2 mutational status in future pharmacogenetic treatment of these individuals.

Amino Acid Sequence↗
PubMed2005

Distinct expression profile in fumarate-hydratase-deficient uterine fibroids.

Defects in mitochondrial enzymes predispose to severe developmental defects as well as tumorigenesis. Heterozygous germline mutations in the nuclear gene encoding fumarate hydratase (FH), an enzyme catalyzing the hydration of fumarate in the Krebs tricarboxylic acid cycle, cause hereditary leiomyomatosis and renal cell cancer; yet the connection between disruption of mitochondrial metabolic pathways and neoplasia remains to be discovered. We have used an expression microarray approach for studying differences in global gene expression pattern caused by mutations in FH. Seven uterine fibroids carrying FH mutations were compared with 15 fibroids with wild-type FH. The two groups showed markedly different expression profiles, and multiple differentially expressed genes were detected. The most significant increase in FH mutants was seen in the expression of carbohydrate metabolism- and glycolysis-related genes. Other significantly up-regulated gene categories in FH mutants were, for example, iron ion homeostasis and oxidoreduction. Genes with lower expression in FH-mutant fibroids belonged to groups such as extracellular matrix, cell adhesion, muscle development and cell contraction. We show that FH mutations alter significantly the expression profiles of fibroids, most strikingly increasing the expression of genes involved in glycolysis.

Blotting, Western↗
PubMed2005

Proteome profiling of corneal epithelium and identification of marker proteins for keratoconus, a pilot study.

The purpose of this study is to identify corneal proteins differentially expressed between keratoconus and normal epithelial samples. Proteins from the corneal epithelium were isolated from 6 keratoconus and 6 myopia patients (controls) and separated by 2D-gel electrophoresis. Six % and 12% SDS-PAGE gels were used to separate low and high molecular weight proteins. Gels were silver stained and protein spots were defined by Melanie II software. The proteins that were most altered in expression comparing keratoconus and controls were extracted, trypsin-digested, and identified by mass spectroscopy. Approximately 200-500 protein spots were detected on each gel. Nineteen spots were identified as differentially expressed between keratoconus and reference epithelium including cytokeratin 3 (< 7.8 fold), gelsolin (1.6 fold), S100A4 (1.9 fold), and enolase 1 (0.72 fold). Another identified protein found at very high levels was cytokeratin 12. Gelsolin, cytokeratin 3, and cytokeratin 12 have previously been described to be involved in other corneal diseases. Three proteins, gelsolin, alpha enolase, and S100A4 were identified to be differentially expressed in keratoconus compared to reference epithelium and thus may be involved in the pathogenesis.

Biomarkers↗
PubMed2005

A molecular signature in superficial bladder carcinoma predicts clinical outcome.

PURPOSE: Cancer of the urinary bladder is a common malignant disease in the western countries. The majority of patients presents with superficial tumors with a high recurrence frequency, a minor fraction of these patients experience disease progression to a muscle invasive stage. No clinical useful molecular markers exist to identify patients showing later disease progression. The purpose of this study was to identify markers of disease progression using full-genome expression analysis. EXPERIMENTAL DESIGN: We did a full-genome expression analysis (59,619 genes and expressed sequence tags) of superficial bladder tumors from 29 bladder cancer patients (13 without later disease progression and 16 with later disease progression) using high-density oligonucleotide microarrays. We used supervised learning for identification of the optimal genes for predicting disease progression. The identified genes were validated on an independent test set (74 superficial tumor samples) using in house-fabricated 60-mer oligonucleotide microarrays. RESULTS: We identified a 45-gene signature of disease progression. By monitoring this progression signature in an independent test set, we found a significant correlation between our classifications and the clinical outcome (P < 0.03). The genes identified as differentially expressed were involved in regulating apoptosis, cell differentiation, and cell cycle and hence may represent potential therapeutic targets. CONCLUSIONS: Our results indicate that it may be possible to identify patients with a high risk of disease progression at an early stage using a molecular signature present already in the superficial tumors. In this way, better treatment and follow-up regimens could be assigned to patients suffering from superficial bladder cancer.

Cluster Analysis↗
PubMed2005

Gene expression changes induced by bismuth in a macrophage cell line.

We have investigated the effect of bismuth by autometallography, cell viability, TUNEL assay and microarray analysis of a macrophage cell line. The cells accumulate bismuth in their lysosomes in a time- and dose-dependent manner. Cell viability assays show a significant decrease in the number of viable cells related to both bismuth concentrations and exposure time. TUNEL assays after 12 h and 24 h at a bismuth-citrate concentration of 50 microM revealed the presence of 30% and 70% TUNEL-positive cells, respectively, compared with 8% in the controls. We have analysed gene expression profiles for cells exposed to 50 microM bismuth-citrate and for untreated controls at 12 h and 24 h by microarray analysis, which confirmed that bismuth is a powerful metallothionein inducer. A number of glycolytic enzymes are induced by bismuth, suggesting that bismuth is able to induce "hypoxia-like" stress. BCL2/adenovirus E1B 19-kDa-interacting protein 3 (Bnip3) has been suggested as a regulator of hypoxia-induced cell death independent of caspase-3 activation and cytochrome c release. Bnip3 is up-regulated indicating the involvement of Bnip3 as a possible mechanism for bismuth-induced cell death. Differences have been noticed in cell viability and in the modification of the mRNA expression levels at 12 and 24 h. Only 13 genes are modified at both these times, suggesting a time-dependent molecular cascade in which bismuth-exposed cells enter a dormant stage with mRNA down-regulation being followed by cell death of susceptible cells.

Animals↗
PubMed2005

Molecular staging for survival prediction of colorectal cancer patients.

PURPOSE: The Dukes' staging system is the gold standard for predicting colorectal cancer prognosis; however, accurate classification of intermediate-stage cases is problematic. We hypothesized that molecular fingerprints could provide more accurate staging and potentially assist in directing adjuvant therapy. METHODS: A 32,000 cDNA microarray was used to evaluate 78 human colon cancer specimens, and these results were correlated with survival. Molecular classifiers were produced to predict outcome. RESULTS: Molecular staging, based on 43 core genes, was 90% accurate (93% sensitivity, 84% specificity) in predicting 36-month overall survival in 78 patients. This result was significantly better than Dukes' staging (P = .03878), discriminated patients into significantly different groups by survival time (P < .001, log-rank test), and was significantly different from chance (P < .001, 1,000 permutations). Furthermore, the classifier was able to discriminate a survival difference in an independent test set from Denmark. Molecular staging identifies patient prognosis (as represented by 36-month survival) more accurately than the traditional clinical staging, particularly for intermediate Dukes' stage B and C patients. The classifier was based on a core set of 43 genes, including osteopontin and neuregulin, which have biologic significance for this disease. CONCLUSION: These data support further evaluation of molecular staging to discriminate good from poor prognosis patients, with the potential to direct adjuvant therapy.

Adult↗
PubMed2005

High-density single nucleotide polymorphism array defines novel stage and location-dependent allelic imbalances in human bladder tumors.

Bladder cancer is a common disease characterized by multiple recurrences and an invasive disease course in more than 10% of patients. It is of monoclonal or oligoclonal origin and genomic instability has been shown at certain loci. We used a 10,000 single nucleotide polymorphism (SNP) array with an average of 2,700 heterozygous SNPs to detect allelic imbalances (AI) in 37 microdissected bladder tumors from 17 patients. Eight tumors represented upstaging from Ta to T1, eight from T1 to T2+, and one from Ta to T2+. The AI was strongly stage-dependent as four chromosomal arms showed AI in > 50% of Ta samples, eight in T1, and twenty-two in T2+ samples. The tumors showed stage-dependent clonality as 61.3% of AIs were reconfirmed in later T1 tumors and 84.4% in muscle-invasive tumors. Novel unstable chromosomal areas were identified at chromosomes 6q, 10p, 16q, 20p, 20q, and 22q. The tumors separated into two distinct groups, highly stable tumors (all Ta tumors) and unstable tumors (2/3 muscle-invasive). All 11 unstable tumors had lost chromosome 17p areas and 90% chromosome 8 areas affecting Netrin-1/UNC5D/MAP2K4 genes as well as others. AI was present at the TP53 locus in 10 out of 11 unstable tumors, whereas 6 had homozygous TP53 mutations. Tumor distribution pattern reflected AI as seven out of eight patients with additional upper urinary tract tumors had genomic stable bladder tumors (P < 0.05). These data show the power of high-resolution SNP arrays for defining clinically relevant AIs.

Allelic Imbalance↗
PubMed2005

Down-modulation of poly(ADP-ribose) polymerase-1 (PARP-1) in human TUR leukemia cells restores transcriptional responsiveness for differentiation and cell cycle arrest.

Aggressive tumor developing human TUR myeloid leukemia cells continued cell cycle progression in the presence of the differentiation-inducing phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Similar results were obtained after stable transfection of TUR cells with the pTracer control vector (pTracer TUR cells). In contrast, TUR transfectants containing a constitutively active poly(ADP-ribose) polymerase-1 (PARP-1) gene fragment in antisense orientation within the pTracer vector (asPARP TUR cells) demonstrated increasing cell attachment and differentiation after TPA treatment. Moreover, asPARP TUR cells ceased to divide upon TPA stimulation. Cell cycle analysis revealed a predominant G0/G1 arrest and a partial G2/M arrest in TPA-treated asPARP TUR cells, whereas little if any population was detectable in S phase. Microarray gene expression analysis exhibited a significant down-regulation of cell cycle genes in phorbol ester-stimulated asPARP TUR and markedly elevated levels of differentiation-associated factors in contrast to TPA-incubated wild-type TUR cells. Whereas PARP-1 can associate with the 20S proteasome in leukemia cells, a significant reduction of this proteolytic activity was observed in asPARP TUR cells. Conversely, protein levels of manganese superoxide dismutase and the matrix metalloproteinases MMP-1 and MMP-9 were progressively increased in TPA-treated asPARP TUR cells, respectively. These findings underscore an important function of PARP-1 in human leukemia cells to connect cell cycle progression and control of differentiation.

Cell Adhesion↗
PubMed2004

Identification of the genes up- and down-regulated by the high mobility group A1 (HMGA1) proteins: tissue specificity of the HMGA1-dependent gene regulation.

High mobility group A (HMGA) proteins are chromatinic proteins that do not have transcriptional activity per se, however, by interacting with the transcription machinery, they regulate, negatively or positively, the expression of several genes. We searched for genes regulated by HMGA1 proteins using microarray analysis in embryonic stem (ES) cells bearing one or two disrupted hmga1 alleles. We identified 87 transcripts increased and 163 transcripts decreased of at least 4-fold in hmga1-/- ES cells. For some of them, a HMGA1-dose dependency was observed, because an intermediate level was observed in the heterozygous ES cells. When the expression analysis of these genes was extended to embryonic fibroblasts and adult tissues such as heart, spleen, and liver from hmga1-knockout mice, contrasting results were obtained. In fact, aside some genes showing the same HMGA1 regulation observed in ES cells, there were some genes that did not modify their expression, and others showing a HMGA1-mediated regulation but in an opposite direction. These results clearly indicate that HMGA1-mediated gene regulation depends on the cellular context. Finally for a couple of analyzed HMGA1-regulated genes, electrophoretic mobility shift assay and chromatin immunoprecipitation revealed a direct binding of HMGA1 proteins to their promoters, suggesting a HMGA1-direct regulation of their expression.

Animals↗
PubMed2004

Autocrine stimulation by osteopontin plays a pivotal role in the expression of the mitogenic and invasive phenotype of RET/PTC-transformed thyroid cells.

Papillary thyroid carcinomas are characterized by rearrangements of the RET receptor tyrosine kinase generating RET/PTC oncogenes. Here we show that osteopontin (OPN), a secreted glycoprotein, is a major RET/PTC-induced transcriptional target in PC Cl 3 thyroid follicular cells. OPN upregulation depended on the integrity of the RET/PTC kinase and tyrosines Y1015 and Y1062, two major RET/PTC autophosphorylation sites. RET/PTC also induced a strong overexpression of CD44, a cell surface signalling receptor for OPN. Upregulation of CD44 was dependent on RET/PTC Y1062, as well. Constitutive OPN overexpression or treatment with exogenous recombinant OPN sharply increased proliferation, Matrigel invasion and spreading in collagen gels of RET/PTC-transformed PC Cl 3 cells. These effects were impaired by the treatment of PC Cl 3-RET/PTC cells with OPN- and CD44-locking antibodies. Thus, RET/PTC signalling triggers an autocrine loop involving OPN and CD44 that sustains proliferation and invasion of transfomed PC Cl 3 thyrocytes.

Carcinoma, Papillary↗
PubMed2004

Preferential response of cancer cells to zebularine.

The frequent silencing of tumor suppressor genes by altered cytosine methylation and chromatin structural changes makes this process an attractive target for epigenetic therapy. Here we show that zebularine, a stable DNA cytosine methylation inhibitor, is preferentially incorporated into DNA and exhibits greater cell growth inhibition and gene expression in cancer cell lines compared to normal fibroblasts. In addition, zebularine preferentially depleted DNA methyltransferase 1 (DNMT1) and induced expression of cancer-related antigen genes in cancer cells relative to normal fibroblasts. Our results demonstrate that zebularine can be selective toward cancer cells and may hold clinical promise as an anticancer therapy.

Antineoplastic Agents↗
PubMed2003

Multiple colorectal adenomas, classic adenomatous polyposis, and germ-line mutations in MYH.

BACKGROUND: Germ-line mutations in the base-excision-repair gene MYH have been associated with recessive inheritance of multiple colorectal adenomas. Tumors from affected persons displayed excess somatic transversions of a guanine-cytosine pair to a thymine-adenine pair (G:C-->T:A) in the APC gene. METHODS: We screened for germ-line MYH mutations in 152 patients with multiple (3 to 100) colorectal adenomas and 107 APC-mutation-negative probands with classic familial adenomatous polyposis (>100 adenomas). Subgroups were analyzed for changes in the related genes MTH1 and OGG1. Adenomas were tested for somatic APC mutations. RESULTS: Six patients with multiple adenomas and eight patients with polyposis had biallelic germline MYH variants. Missense and protein-truncating mutations were found, and the spectrums of mutations were very similar in the two groups of patients. In the tumors of carriers of biallelic mutations, all somatic APC mutations were G:C-->T:A transversions. In the group with multiple adenomas, about one third of patients with more than 15 adenomas had biallelic MYH mutations. In the polyposis group, no patient with biallelic MYH mutations had severe disease (>1000 adenomas), but three had extracolonic disease. No clearly pathogenic MTH1 or OGG1 mutations were identified. CONCLUSIONS: Germ-line MYH mutations predispose persons to a recessive phenotype, multiple adenomas, or polyposis coli. For patients with about 15 or more colorectal adenomas--especially if no germ-line APC mutation has been identified and the family history is compatible with recessive inheritance--genetic testing of MYH is indicated for diagnosis and calculation of the level of risk in relatives. Clinical care of patients with biallelic MYH mutations should be similar to that of patients with classic or attenuated familial adenomatous polyposis.

Adenoma↗
PubMed2003

The resistance of B-CLL cells to DNA damage-induced apoptosis defined by DNA microarrays.

B-cell chronic lymphoid leukemia (BCLL) is a highly heterogeneous human malignancy, presumably reflecting specific molecular alterations in gene expression and protein activity that are thought to underlie the variable disease outcome. Most B-CLL cell samples undergo apoptotic death in response to DNA damage. However, a clinically distinct aggressive subset of B-CLL is completely resistant in vitro to irradiation-induced apoptosis. We therefore addressed 2 series of microarray analyses on 4 sensitive and 3 resistant B-CLL cell samples and compared their gene expression patterns before and after apoptotic stimuli. Data analysis pointed out 16 genes whose expression varied at least 2-fold specifically in resistant cells. We validated these selected genes by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) on 7 microarray samples and confirmed their altered expression level on 15 additional B-CLL cell samples not included in the microarray analysis. In this manner, in 11 sensitive and 11 resistant B-CLL cell samples tested, 13 genes were found to be specific for all resistant samples: nuclear orphan receptor TR3, major histocompatibility complex (MHC) class II glycoprotein HLA-DQA1, mtmr6, c-myc, c-rel, c-IAP1, mat2A, and fmod were up-regulated, whereas MIP1a/GOS19-1 homolog, stat1, blk, hsp27, and ech1 were down-regulated. In some cases, the expression profile may be dependent on the status of p53. Some of these genes encode general apoptotic factors but also exhibit lymphoid cell specificities that could potentially be linked to the development of lymphoid malignancies (MIP1alpha, blk, TR3, mtmr6). Taken together, our data define new molecular markers specific to resistant B-CLL subsets that might be of clinical relevance.

Apoptosis↗
PubMed2003

EXO1 variants occur commonly in normal population: evidence against a role in hereditary nonpolyposis colorectal cancer.

Mutations in the currently known mismatch repair genes cannot explain all cases of hereditary nonpolyposis colorectal cancer (HNPCC), and novel predisposing genes are actively sought. Recently, mutations in the DNA repair gene EXO1 have been implicated in HNPCC. One truncating and several missense changes were observed in familial colorectal cancer (CRC) cases but not in controls. We evaluated a series of European CRC patients and population controls to clarify whether EXO1 variants may indeed predispose to familial CRC. Several variants observed in patients were also observed in controls with similar frequencies, including the truncating variant proposed previously to be a disease-causing mutation. Thus, little evidence was obtained to support a major causative role of EXO1 in HNPCC, although we cannot exclude a role for EXO1 as a low penetrance cancer susceptibility or modifying gene.

Amino Acid Sequence↗
PubMed2002

Identifying distinct classes of bladder carcinoma using microarrays.

Bladder cancer is a common malignant disease characterized by frequent recurrences. The stage of disease at diagnosis and the presence of surrounding carcinoma in situ are important in determining the disease course of an affected individual. Despite considerable effort, no accepted immunohistological or molecular markers have been identified to define clinically relevant subsets of bladder cancer. Here we report the identification of clinically relevant subclasses of bladder carcinoma using expression microarray analysis of 40 well characterized bladder tumors. Hierarchical cluster analysis identified three major stages, Ta, T1 and T2-4, with the Ta tumors further classified into subgroups. We built a 32-gene molecular classifier using a cross-validation approach that was able to classify benign and muscle-invasive tumors with close correlation to pathological staging in an independent test set of 68 tumors. The classifier provided new predictive information on disease progression in Ta tumors compared with conventional staging (P < 0.005). To delineate non-recurring Ta tumors from frequently recurring Ta tumors, we analyzed expression patterns in 31 tumors by applying a supervised learning classification methodology, which classified 75% of the samples correctly (P < 0.006). Furthermore, gene expression profiles characterizing each stage and subtype identified their biological properties, producing new potential targets for therapy.

Disease Progression↗
PubMed2002

Analysis of gene induction in human fibroblasts and bladder cancer cells exposed to the methylation inhibitor 5-aza-2'-deoxycytidine.

Hypermethylation of the promoters of cancer-related genes is often associated with their inactivation during tumorigenesis. Several preclinical and clinical trials have been developed to use DNA methylation inhibitors, such as 5-aza-2'-deoxycytidine (5-Aza-CdR) in attempts to reactivate silenced genes in human cancers. We used high-density oligonucleotide gene expression microarrays to examine the effects of 5-Aza-CdR treatment on human fibroblast cells (LD419) and a human bladder tumor cell line (T24). Data obtained 8 days after recovery from 5-Aza-CdR treatment showed that more genes were induced in tumorigenic cells (61 genes induced; >or=4-fold) than nontumorigenic cells (34 genes induced; >or= 4-fold). Approximately 60% of induced genes did not have CpG islands within their 5' regions, suggesting that some genes activated by 5-Aza-CdR may not result from the direct inhibition of promoter methylation. Interestingly, a high percentage of genes activated in both cell types belonged to the IFN signaling pathway, confirming data from other tumor cell types.

Antimetabolites, Antineoplastic↗