Biomedical subjects

Iver Petersen

Publications and source records attributed to Iver Petersen.

At least 19 recordsLinked to original sources

PubMed2006

5-Bromodeoxyuridine induced differentiation of a human small cell lung cancer cell line is associated with alteration of gene expression.

Small cell lung cancer (SCLC) appears to arise from neuroendocrine cells with the potential to differentiate into a variety of lung epithelial cell lineages. In order to investigate molecular events underlying the cell type transition in SCLC, we treated a SCLC cell line H526 with a differentiation inducing agent 5-bromodeoxyuridine (BrdU). The treatment led to a dramatic conversion from suspension cells to adherent cells exhibiting an epithelioid phenotype, which remarkably reduced the ability of colony formation in soft agar and suppressed the tumor growth rate in nude mice. The phenotypic transition was consistent with upregulation of surfactant protein C (SFTPC), thyroid transcription factor 1 (TTF-1), Connexin 26 (Cx26), insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1), as well as homeobox genes LAGY, PITX1, and HOXB2. Our data suggest that BrdU induced cell differentiation could be linked to the development of a less aggressively phenotype in small cell lung cancer.

Animals↗

PubMed2006

Decreased PITX1 homeobox gene expression in human lung cancer.

The PITX1 (pituitary homeobox 1) gene has essential roles in human development and has been considered a tumor suppressor in various cancers. However, in lung cancer the role of PITX1 remains to be elucidated. In this study, we analyzed the expression of PITX1 at both mRNA and protein levels in human lung cancer. The reduced PITX1 expression was found in cancer cell lines test compared to normal human bronchial epithelia cells (HEBC) and small airway epithelia cells (SAEC) by Northern blot analysis and RT-PCR as well as Western blot analysis. In primary lung tissues, PITX1 mRNA was found to be downregulated in the majority of tumors compared with normal lung tissues. An association between the lack of PITX1 mRNA expression and higher tumor grade was observed. A tissue microarray containing 135 primary lung carcinomas was analyzed by immunohistochemistry. Eighty-four cases (62%) exhibited no expression of PITX1 and the lower expression of PITX1 was significantly linked to higher tumor stages. Additionally, PITX1 was found to be upregulated in lung cancer cell lines H2228 and H526 after they were exposed to a differentiation modifying agent 5-bromodeoxyuridine (BrdU). Since homeobox genes are known to transcriptionally regulate key cellular processes and associated with differentiation and carcinogenesis, we suggest that PITX1 might be linked to lung cancer development and progression.

Carcinoma, Non-Small-Cell Lung↗

PubMed2006

Decreased expression of insulin-like growth factor binding protein 7 in human colorectal carcinoma is related to DNA methylation.

PURPOSE: Insulin-like growth factor binding protein 7 (IGFBP-7) is considered a tumor suppressor in various cancers, but its role in colorectal cancer (CRC) is still uncertain. The aims of this study were to analyze the IGFBP-7 expression, and explore the mechanism responsible for the inactivation of IGFBP-7 in CRC. METHODS: mRNA expression was studied by RT-PCR and Northern blot analysis of cultured cells. Methylation status was analyzed by treatment with 5-aza-2'-deoxycytidine followed by sequencing of PCR products of sodium bisulfite-treated genomic DNA. IGFBP-7 protein expression was evaluated by immunohistochemistry (IHC) on tissue microarrays. RESULTS: mRNA expression was lost in six out of eight CRC cell lines as compared to normal colon cells. DNA methylation was found in the region of exon 1 and intron 1 of IGFBP-7. In tumor tissue, 107 out of 279 samples showed a negative expression of IGFBP-7 by IHC, which was significantly associated with poor prognosis. The analysis of 37 paired cancerous and normal mucosa samples confirmed the downregulation in the tumors, but revealed variable basal expression levels of IGFBP-7 in normal mucosal samples. CONCLUSIONS: DNA methylation is a mechanism responsible for IGFBP-7 gene silencing providing a target for therapeutic intervention of this tumor suppressor gene.

Cell Line, Tumor↗

PubMed2006

Nuclear export is essential for the tumor-promoting activity of survivin.

Survivin appears to function as an apoptosis inhibitor and a regulator of cell division during development and tumorigenesis. Here we report the molecular characterization of the nucleocytoplasmic transport of survivin and its potential implications for tumorigenesis. We identified an evolutionary conserved Crm1-dependent nuclear export signal (NES) in survivin. In dividing cells, the NES is essential for tethering survivin and the survivin/Aurora-B kinase complex to the mitotic machinery, which in turn appears to be essential for proper cell division. In addition, export seems to be required for the cytoprotective activity of survivin, as export-deficient survivin fails to protect tumor cells against chemo- and radiotherapy-induced apoptosis. These findings appear to be clinically relevant since preferential nuclear localization of survivin correlated with enhanced survival in colorectal cancer patients. Targeting survivin's nuclear export by the application of NES-specific antibodies promoted its nuclear accumulation and inhibited its cytoprotective function. We demonstrate that nuclear export is essential for the biological activity of survivin and promote the identification of molecular decoys to specifically interfere with survivin's nuclear export as potential anticancer therapeutics.

Apoptosis↗

PubMed2006

Synchronous adenocarcinomas of intestinal type of the inner nose and the colon.

Intestinal types of adenocarcinoma of the inner nose and colorectal adenocarcinoma present a stupendous similarity of morphological and immunohistochemical features. The previously unpublished observation of a synchronous manifestation of both adenocarcinoma enabled us to compare the tumors using molecular and immunohistochemical methods. Polymerase chain reaction was performed in order to investigate microsatellite instability. Mutation of p53 and K-ras was examined by direct DNA sequencing. Chromosomal imbalances were investigated by comparative genomic hybridization. Histology and immunohistochemical reactions were nearly identical. PCR results revealed no microsatellite instability or loss of heterozygosity in any of the tumors. A p53 mutation in exon 5 could be detected in the colon tumor but not in the sinonasal carcinoma, while a K-ras mutation was only present in the tumor of the inner nose. The comparative genomic hybridization method revealed different chromosomal imbalances in the different tumors. Thus, the molecular pathologic data proved the presence of 2 independent primary adenocarcinomas of the intestinal type.

Adenocarcinoma↗

PubMed2006

Anaplastic large-cell non-Hodgkin's lymphoma of the breast in periprosthetic localisation 32 years after treatment for primary breast cancer--a case report.

Primary, as well as secondary, lymphomas of the breast are rare diseases and might, in some cases, be misdiagnosed as breast cancer on routine hematoxylin/eosin stainings. We report a case of an anaplastic large cell lymphoma in a 72-year-old woman with a history of breast cancer treated with breast-ablative surgery and a subsequent silicon implant 32 years ago. Clinically, she presented with an ulceration of the skin, which had developed within a few months. On conventional histology, the tumor cells were mimicking poorly differentiated invasive ductal carcinoma with a prominent leukocytic infiltrate. The immunoprofile of the tumor showed negativity for cytokeratins and led to the diagnosis of a CD30-positive anaplastic large cell lymphoma.

Aged↗

PubMed2006

Chromosomal alterations in lung metastases of colorectal carcinomas: associations with tissue specific tumor dissemination.

Comparative genomic hybridization was used to screen colorectal carcinomas for chromosomal aberrations that are associated with the metastatic phenotype of the lung. Specimens of 13 lung metastases, 6 primary tumors, 1 lymph node metastasis, 1 liver metastasis, and 1 ovarian metastasis were investigated and added to our CGH colon cancer tumor collective, comprising 85 tumor specimens from 56 patients (see CGH online tumor database at http://amba.charite.de/cgh). Lung metastases showed more alterations than liver metastases, particularly more deletions at 1p, 3p, 9q, 12q, 17q, 19p and 22q and gains at 2q, 5p, and chromosome 6. Comparing lung metastases with their corresponding primary tumors, particularly more deletions at 3p, 8p, 12q, 17q, and 21q21 and gains at 5p were observed. Based on our results, we wish to suggest a metastatic progression model. Specific subpopulations of metastatic cells have a distinct metastatic potential, which is reflected by a non-random accumulation of chromosomal alterations. Distinct alterations already exist within the primary tumor and this "ready to go package" gives the cells the metastatic potential to achieve the complex series of events needed for metastasis.

Chromosome Aberrations↗

PubMed2006

Genetic background of different cancer cell lines influences the gene set involved in chromosome 8 mediated breast tumor suppression.

Several lines of evidence suggest that chromosome 8 is likely to harbor tumor-suppressor genes involved in breast cancer. We showed previously that microcell-mediated transfer of human chromosome 8 into breast cancer cell line MDA-MB-231 resulted in reversion of these cells to tumorigenicity and was accompanied by changes in the expression of a breast cancer-relevant gene set. In the present study, we demonstrated that transfer of human chromosome 8 into another breast cancer cell line, CAL51, strongly reduced the tumorigenic potential of these cells. Loss of the transferred chromosome 8 resulted in reappearance of the CAL51 phenotype. Microarray analysis identified 78 probe sets differentially expressed in the hybrids compared with in the CAL51 and the rerevertant cells. This signature was also reflected in a panel of breast tumors, lymph nodes, and distant metastases and was correlated with several prognostic markers including tumor size, grading, metastatic behavior, and estrogen receptor status. The expression patterns of seven genes highly expressed in the hybrids but down-regulated in the tumors and metastases (MYH11, CRYAB, C11ORF8, PDGFRL, PLAGL1, SH3BP5, and KIAA1026) were confirmed by RT-PCR and tissue microarray analyses. Unlike with the corresponding nontumorigenic phenotypes demonstrated for the MDA-MB-231- and CAL51-derived microcell hybrids, the respective differentially expressed genes strongly differed. However, the majority of genes in both gene sets could be integrated into a similar spectrum of biological processes and pathways, suggesting that alterations in gene expression are manifested at the level of functions and pathways rather than in individual genes.

Animals↗

PubMed2006

Cytokeratin profiles identify diagnostic signatures in colorectal cancer using multiplex analysis of tissue microarrays.

BACKGROUND AND AIMS: Recent cDNA expression profiling analyses indicate that within specific organ cancers Cytokeratins (CKs) dysregulation may identify subgroups with distinct biological phenotypes. Our objectives in this study were (1) to test whether cytokeratins were also distinct on the protein level, (2) to evaluate these biomarkers in a series of well-characterised CRCs, (3) to apply hierarchical cluster analysis to immunohistochemical data. METHODS: Tissue microarrays (TMA) comprising 468 CRC specimens from 203 patients were constructed to evaluate CK5, CK7, CK8, CK13, CK14, CK16, CK17, CK18, CK19 and CK20. In total, 2919 samples were analyzed. RESULTS: Unsupervised hierarchical clustering discovered subgroups represented by reduced CK8 and CK20 expression, that differed by a shorter patients survival. The evaluation of the specific biomarkers by Kaplan-Meier analysis showed that reduced CK8 expression (p<0.01) was significantly associated with shorter patients' survival, but was not an independent factor correlated with tumour stage (pT), grading (G) and nodal stage (pN). CONCLUSIONS: Reduced coexpression of CK8 and CK20 may indicate an epithelial-mesenchymal transition (EMT) representing an important step in the development of more aggressive CRCs. In addition, multiplex analysis of TMAs together with immunohistochemistry (IHC) supplemented by hierarchical clustering are a useful, promising and very powerful tool for the identification of tumour subgroups with diagnostic and prognostic signatures.

Biomarkers, Tumor↗

PubMed2006

HPV typing and CGH analysis for the differentiation of primary and metastatic squamous cell carcinomas of the aerodigestive tract.

Human papilloma virus (HPV) typing and Comparative Genomic Hybridisation (CGH) analysis can be used in the classification of multiple tumours of the aerodigestive tract for the differentiation between secondary malignancy versus metastasis. We present 3 exemplary cases of patients with multiple squamous cell carcinomas, localised within the head and neck region, cervical lymph node and the lung. In two patients, HPV typing identified HPV type 16 in the tonsillar carcinomas and the corresponding cervical lymph node and lung carcinoma indicating that the latter were metastatic spreads. In case 1, CGH confirmed the clonal relationship. Case two showed a peculiar syncytial growth pattern with lymphocytic infiltration which may constitute a potential morphological marker for HPV infection. In case three, a vallecular carcinoma was HPV negative while a lung cancer was positive for HPV type 6 indicating two independent primary tumours. Our case triplet illustrates the variability of HPV infection in squamous cell cancer of the aerodigestive tract and power as well as limitations of morphology, HPV typing and tumour genetics in the classification of multiple tumours.

Carcinoma, Squamous Cell↗

PubMed2006

H-REV107-1 stimulates growth in non-small cell lung carcinomas via the activation of mitogenic signaling.

H-REV107-1, a known member of the class II tumor suppressor gene family, is involved in the regulation of differentiation and survival. We analyzed H-REV107-1 in non-small cell lung carcinomas, in normal lung, and in immortalized and tumor-derived cell lines. Sixty-eight percent of lung tumors revealed positive H-REV107-1-specific staining. Furthermore, survival analysis demonstrated a significant association of cytoplasmic H-REV107-1 with decreased patient survival. This suggested that H-REV107-1, known as a tumor suppressor, plays a different role in non-small cell lung carcinomas. Knock-down of H-REV107-1 expression in lung carcinoma cells inhibited anchorage-dependent and anchorage-independent growth whereas overexpression of H-REV107-1 induced tumor cell proliferation. Consistent with results of the survival analysis, cytoplasmic localization of the protein was essential for this growth-inducing function. Analysis of signaling pathways potentially involved in this process demonstrated that overexpression of H-REV107-1 stimulated RAS-GTPase activity, ERK1,2 phosphorylation, and caveolin-1 expression in the cell lines analyzed. These results indicate that H-REV107-1 is deficient in its function as a tumor suppressor in non-small cell lung carcinomas and is required for proliferation and anchorage-independent growth in cells expressing high levels of the protein, thus contributing to tumor progression in a subset of non-small cell lung carcinomas.

Carcinoma, Non-Small-Cell Lung↗

PubMed2005

An improved Tet-On regulatable FasL-adenovirus vector system for lung cancer therapy.

Gene therapy is a new therapeutic approach for the treatment of human cancers. Gene expression systems that can be regulated by drugs have been developed to improve the safety and efficacy of therapeutic transgene delivery. One of the most promising systems is the tetracycline (Tet)-responsive system in the Tet-On configuration. A major problem of the Tet-On system if used in viral vectors is the high basal activity of the Tet response element (TRE) promoter leading to leaky expression of transgenes under uninduced conditions. We therefore evaluated novel TRE promoters for controlling gene expression in an adenovirus vector (AdV) Tet-On system and further investigated them for expression of the pro-apoptotic CD95/Fas ligand (FasL) in human epithelial carcinoma cell line (HeLa) and lung cancer cells. Plasmid-based reporter gene assays showed that modifications within the tetO (7) and minimal immediate early cytomegalovirus promoter (CMV)(min) sequence of the TRE promoter reduced its leakiness and led to a markedly improved regulatability by doxycycline. Among several TRE promoters tested, a new construct (TRE-Tight1) containing modifications of both the tetO (7) sequence and the CMV(min) showed 11-fold reduced leakiness and 1.5-fold increased absolute transgene expression levels after induction, as compared to the original TRE. Under induced conditions, a TRE-Tight1 promoter-dependent AdV expressing the pro-apoptotic CD95L/FasL induced apoptosis and cell lysis in HeLa cells as efficiently as an AdV containing the original TRE promoter. In contrast to the latter, however, the vector with the modified TRE promoter left cells totally unaffected in the absence of the inducer. Stringently regulated induction of apoptosis and cell death by TRE-Tight1-AdV was also demonstrated in three human lung cancer cell lines. These data show that the novel TRE-Tight1 promoter has a high potential for closely controlled and efficient expression of cytotoxic genes in AdV-based anti-cancer approaches.

Adenoviridae↗

PubMed2005

Prediction of doxorubicin sensitivity in breast tumors based on gene expression profiles of drug-resistant cell lines correlates with patient survival.

Up to date clinical tests for predicting cancer chemotherapy response are not available and individual markers have shown little predictive value. We hypothesized that gene expression patterns attributable to chemotherapy-resistant cells can predict response and cancer prognosis. We contrasted the expression profiles of 13 different human tumor cell lines of gastric (EPG85-257), pancreatic (EPP85-181), colon (HT29) and breast (MCF7 and MDA-MB-231) origin and their counterparts resistant to the topoisomerase inhibitors daunorubicin, doxorubicin or mitoxantrone. We interrogated cDNA arrays with 43 000 cDNA clones ( approximately 30 000 unique genes) to study the expression pattern of these cell lines. We divided gene expression profiles into two sets: we compared the expression patterns of the daunorubicin/doxorubicin-resistant cell lines and the mitoxantrone-resistant cell lines independently to the parental cell lines. For identifying predictive genes, the Prediction Analysis for Mircorarrays algorithm was used. The analysis revealed 79 genes best correlated with doxorubicin resistance and 70 genes with mitoxantrone resistance. In an independent classification experiment, we applied our model of resistance for predicting the sensitivity of 44 previously characterized breast cancer samples. The patient group characterized by the gene expression profile similar to those of doxorubicin-sensitive cell lines exhibited longer survival (49.7+/-26.1 months, n=21, P=0.034) than the resistant group (32.9+/-18.7 months, n=23). The application of gene expression signatures derived from doxorubicin-resistant and -sensitive cell lines allowed to predict effectively clinical survival after doxorubicin monotherapy. Our approach demonstrates the significance of in vitro experiments in the development of new strategies for cancer response prediction.

Algorithms↗

PubMed2005

Unusual sarcomatoid neoplasm of the lung suggesting a myofibrosarcoma.

Myofibrosarcoma is a rare neoplasm that occurs mainly in the head and neck region and extremities of middle-aged patients. It often appears as a low-grade sarcoma and rarely metastasizes. We report the case of a 47-year-old male patient with a malignant mesenchymal pulmonary tumor affecting almost the entire lower left lobe. Clinically suggestive for a lung carcinoma, the tumor showed typical features of a myofibrosarcoma. A major spindle cell component was observed being positive for smooth-muscle actin, calponin, and vimentin, while stainings for desmin, h-caldesmon, alkaline phosphatase (ALK), and extensively studied cytokeratins were negative. Striking was a strong infiltrate with neutrophilic and eosinophilic granulocytes. DNA cytometry revealed aneuploidy with a peak in the near triploid range. Comparative genomic hybridization demonstrated multiple DNA gains and losses correlating with an aggressive clinical course. Shortly after resection of the primary tumor, the patient showed multiple distant metastases in the contralateral lung, the mediastinal lymph nodes, the left adrenal gland, and the pectoral and deltoid muscle, which responded well to chemotherapy. The case report will discuss the evidence for the final diagnosis of a primary pulmonary myofibrosarcoma and the differential diagnosis of sarcomatoid tumors of the lung.

Diagnosis, Differential↗

PubMed2005

Microarray comparative genomic hybridization detection of chromosomal imbalances in uterine cervix carcinoma.

BACKGROUND: Chromosomal Comparative Genomic Hybridization (CGH) has been applied to all stages of cervical carcinoma progression, defining a specific pattern of chromosomal imbalances in this tumor. However, given its limited spatial resolution, chromosomal CGH has offered only general information regarding the possible genetic targets of DNA copy number changes. METHODS: In order to further define specific DNA copy number changes in cervical cancer, we analyzed 20 cervical samples (3 pre-malignant lesions, 10 invasive tumors, and 7 cell lines), using the GenoSensor microarray CGH system to define particular genetic targets that suffer copy number changes. RESULTS: The most common DNA gains detected by array CGH in the invasive samples were located at the RBP1-RBP2 (3q21-q22) genes, the sub-telomeric clone C84C11/T3 (5ptel), D5S23 (5p15.2) and the DAB2 gene (5p13) in 58.8% of the samples. The most common losses were found at the FHIT gene (3p14.2) in 47% of the samples, followed by deletions at D8S504 (8p23.3), CTDP1-SHGC- 145820 (18qtel), KIT (4q11-q12), D1S427-FAF1 (1p32.3), D9S325 (9qtel), EIF4E (eukaryotic translation initiation factor 4E, 4q24), RB1 (13q14), and DXS7132 (Xq12) present in 5/17 (29.4%) of the samples. CONCLUSION: Our results confirm the presence of a specific pattern of chromosomal imbalances in cervical carcinoma and define specific targets that are suffering DNA copy number changes in this neoplasm.

Cell Line, Tumor↗

PubMed2005

Inter-laboratory validation of PCR-based detection of Mycobacterium tuberculosis in formalin-fixed, paraffin-embedded tissues.

The present study is based on the initiative for quality assurance in pathology of the German Society of Pathology and the Professional Association of German Pathologists. Four panel laboratories with experience and expertise in polymerase chain reaction (PCR) detection of Mycobacterium tuberculosis were selected to establish the prerequisites for continuous external laboratory trials, in particular, by providing pre-tested specimens and evaluation criteria for participating institutes. In the first step, the four panel laboratories performed an internal trial to test their own reliability and reproducibility. Paraffin sections and DNA preparations from 34 tissues (25 clinical specimens and 9 controls) totalling to 66 samples were evaluated by each panel institute according to their own protocols. The methodologies differed and are described in detail. Despite these differences, a high degree of inter-laboratory reliability was achieved. In this report, we summarise our results including the correlation with the histology and provide recommendations for applying PCR-based methodology for the detection of mycobacterial DNA in surgical specimens. Supplementary data are available online at http://www.charite.de/ch/patho (rubric "Forschung"). Pre-tested specimens are now available for the external trial and can be ordered from the steering institute via Oligene (http://www.oligene.com/). All molecular pathology laboratories are invited to participate in this quality assurance initiative.

Animals↗

PubMed2005

Characterization of {gamma}-aminobutyric acid type A receptor-associated protein, a novel tumor suppressor, showing reduced expression in breast cancer.

Frequent allelic loss of the chromosomal region 17p13 in breast cancer has suggested that more tumor suppressor genes, besides p53, are located in this region. By doing suppression subtractive hybridization to detect differentially expressed genes between the breast cancer cell line CAL51 and a nontumorigenic microcell hybrid CAL/17-1, we identified the gene for the gamma-aminobutyric acid type A (GABA(A)) receptor associated protein (GABARAP), located on 17p13.1. GABARAP displayed high expression levels in the microcell hybrid CAL/17-1 but only weak expression in CAL51 and other breast cancer cell lines tested. Furthermore, we observed large vesicles in CAL/17-1 by immunofluorescence staining, whereas no signal could be detected in the tumor cell line. GABARAP mRNA expression and protein expression were significantly down-regulated in invasive ductal and invasive lobular carcinomas compared with normal breast tissue measured by semiquantitative reverse transcription-PCR and immunohistochemistry, respectively. We assessed that neither mutations in the coding region of the gene nor hypermethylation of CpG islands in the promoter region are responsible for loss of gene expression in CAL51; however, 5-aza-2'-deoxycytidine treatment was effective in gene up-regulation, suggesting a methylation-dependent upstream effect. Stable transfection of GABARAP into CAL51 resulted in an increase of gene expression and remarkably influenced the ability of colony formation in soft agar and the growth rate in vitro and, moreover, suppressed the tumorigenicity of the cells in nude mice. In summary, our data suggest that GABARAP acts via a vesicle transport mechanism as a tumor suppressor in breast cancer.

Adaptor Proteins, Signal Transducing↗

PubMed2005

Downregulation of connexin 26 in human lung cancer is related to promoter methylation.

Cell-Cell communication via gap junctions plays a key role in carcinogenesis and in growth control. One of the gap junction proteins, Connexin 26 (Cx26) was considered as tumor suppressor in various cancers. In our study, the expression of Cx26 was analyzed in human lung cancer. The reduced mRNA expression was observed in 17 lung cancer cell lines examined by Northern blot analysis and RT-PCR. In 138 primary carcinomas comprising all subtypes analyzed by immunohistochemistry, 85 cases (62%) exhibited no expression of Cx26, whereas in other 53 cases the Cx26 staining was positive (38%). Additionally, an association between Cx26 protein expression and higher grading of tumors was found in whole tumor samples (p =0.028) but no statistically significant correlations could be observed with tumor stage, tumor size and node status. In squamous cell carcinoma, tumors with higher stage and grading were linked to higher expression of Cx26 (p = 0.015 and 0.017, respectively). To explore the mechanism responsible for the downregulation of Cx26, we treated 2 lung cancer cell lines H2170 and H226 with the demethylation agent 5-aza-2'-deoxycytidine and found the reexpression of Cx26 mRNA. Methylation status of these 2 cell lines was further analyzed by PCR amplification of bisulfite modified DNA and sequencing. A heterogeneous methylation pattern turned out. Our results suggest the inactivation of Cx26 in lung cancer may be explained by promoter methylation.

Actins↗