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Biomedical subjects

M Dietel

Publications and source records attributed to M Dietel.

At least 19 recordsLinked to original sources
PubMed2000

Gene expression profiling of advanced lung cancer.

Lung cancer is a highly aggressive neoplasm with 85% mortality. To identify new tumor-associated genes, we compared the expression profile of a primary metastasizing adenocarcinoma with normal airway epithelial cells. Two cDNA libraries of up- and downregulated genes were generated, comprising 253 and 299 clones, respectively. The sequence analysis revealed 205 different known genes and 314 cDNA fragments of unknown functions. Northern-blot analysis of 167 clones confirmed differential expression in 58%, and indicated a similar expression pattern in additional lung-cancer cell lines for selected clones, strengthening the value of this model for the identification of new candidate genes in lung carcinogenesis.

Chromosome Mapping↗
PubMed2000

Specificity of PCR-based clonality analysis of immunoglobulin heavy chain gene rearrangements for the detection of bone marrow involvement by low-grade B-cell lymphomas.

A study was performed to investigate the utility of polymerase chain reaction (PCR)-based analysis of immunoglobulin heavy chain (IgH) gene rearrangements for the diagnosis of low-grade malignant B-cell lymphomas on formalin-fixed, EDTA-decalcified, and paraffin-embedded bone marrow trephine biopsies. On amplifying two DNA samples per biopsy, no reproducible monoclonal PCR result was found in 32 patients with reactive lymphoid hyperplasias. In contrast, 5/14 patients with known low-grade B-cell lymphomas, but histomorphologically and immunohistochemically lymphoma-free bone marrow, showed a reproducible monoclonal IgH gene rearrangement. In three of these cases, sequence analysis revealed completely different amplification products on comparing bone marrow and lymph node infiltrations, while in the other two cases the products were identical. In one of the latter biopsies, an unequivocal lymphoma infiltrate was found after step sectioning of the biopsy, while the other case remained lymphoma-free according to conventional criteria. A third group of three patients with known lymphomas and bone marrow findings that were suggestive but not diagnostic of bone marrow involvement showed monoclonal PCR results in all three cases, with identical sequences in bone marrow and extramedullary lymphoma infiltrates. These data suggest that a reproducible monoclonal IgH gene rearrangement is highly specific for the presence of malignant B-cells in bone marrow. In staging procedures for low-grade B-cell lymphomas, PCR yields no additional information in cases that are morphologically and immunohistochemically lymphoma-free after evaluation of representative sections. PCR may be useful in equivocal cases, provided that IgH gene rearrangements of extramedullary lymphoma and bone marrow are sequenced and compared.

Adult↗
PubMed2000

Pathologic correlation of sonographic echogenic foci in the fetal heart.

The goal of the current paper is to present, on the basis of six investigated fetal hearts, the pathological substrate of prenatally, sonographically diagnosed echogenic intramyocardial foci. The right ventricle, left ventricle, interventricular septum and papillary muscles of both ventricles of six hearts of the fetuses of high-risk pregnant women showing sonographically diagnosed intramyocardial echogenic foci were investigated. At termination of pregnancy all the women were between the 20th and the 24th week of gestation. Of the six cases, four were induced abortions and two were spontaneous abortions. For the control group we investigated the hearts of two fetuses without heart defects at the 22nd and 23rd week of gestation which had proven extracardial anomalies and a normal karyotype. Both cases were induced abortions which prenatally showed no echogenic cardiac foci. In all eight cases a prenatal karyotyping was performed. In the six cases with echogenic foci the location and number of the foci were determined both prenatally and by means of histologic sections; the size of the foci was measured as well. Histological staining was with routine haematoxylin-eosin; Masson-Goldner was used for connective tissue; Kossa for calcification; and Berlin blue for haemosiderin. Histologically, in all six cases, intramyocardial calcifications surrounded by fibrotic tissue were in: papillary muscle of the left ventricle in six cases; papillary muscle of the right ventricle in one case; and the subendocardial myocardium of the right ventricle in one case. Four cases had one, one case had two and one case had three calcified foci. Three cases had cardiac and two cases had extracardiac anomalies. Four cases had chromosome anomalies: two were trisomy 21, one trisomy 13 and one triploidy. The remaining two cases had a normal karyotype. No case showed pathological changes of the chordae tendinae, myocardial cell necrosis or inflammation. There were no patho-morphological differences between the intramyocardial calcifications of the papillary muscles in cases with chromosome anomalies and with normal karyotype. As the patho-morphological correlate of the sonographically diagnosed echogenic foci, histological investigation on all six fetal hearts showed coarse intramyocardial calcifications surrounded by myocardial fibrosis. Conventional histological methods gave no indication of the cause of the intramyocardial calcifications.

Abortion, Induced↗
PubMed2000

An unusual case of leukemic non-Hodgkin's lymphoma with blastic transformation.

We report on a patient who was diagnosed as having B-cell chronic lymphocytic leukemia (CLL) with atypical morphology. Flow cytometry disclosed CD5, CD19, and CD23 positivity, an immunophenotype seen mostly in B-CLL. Histology of the spleen and bone marrow suggested a diagnosis of small lymphocytic lymphoma. Upon blastic transformation, only 3 years after the diagnosis had been made, unusual clinical and laboratory features emerged. Lymphoid blasts appeared in the peripheral blood, and the patient developed nodular infiltrates consisting of these blasts at recent venous puncture sites. The patient did not respond to chemotherapy and died. The lymphoid blasts in the peripheral blood were CD5-, CD19+, and CD23+ and harbored t(11;14) (q13;q32) and t(11;21)(p11;q21) translocations. To account for the possibility of two independent lymphoid malignancies, molecular genetic analyses were performed on samples from the spleen, bone marrow and a lymph node with the large-cell lymphoma, which showed identical clones in these tissues. This unusual case supports the idea that in leukemic non-Hodgkin's lymphoma, in addition to morphology, an accurate diagnostic workup requires immunophenotypic, cytogenetic, and molecular studies.

CD5 Antigens↗
PubMed2000

Human papilloma virus status and chromosomal imbalances in primary cervical carcinomas and tumour cell lines.

Human papilloma virus (HPV) infection is the crucial step in the initiation of cervical carcinomas. In addition, HPV18 has been implicated in tumour progression and adverse clinical outcome. We determined the HPV types in 12 primary cervical carcinomas and 12 cell lines and compared the findings with the comparative genetic hybridisation (CGH) pattern of chromosomal alterations. The most frequent alteration was the deletion at 3p14 followed by the loss of 2q34-q36 along with 3q gain. High risk HPV types were detected in all samples except one primary tumour. In contrast to the normal distribution, HPV18 was present in 75% of cases including all cell lines. The cell lines carried a higher number of genetic alterations and a different CGH pattern for several chromosomes than the primary tumours, despite microdissection. Purely HPV18 positive cases indicated a high incidence of imbalances at specific loci with peaks of the histogram coinciding with known HPV integration sites. The study suggests that HPV infection is associated with a recurrent pattern of chromosomal changes in cervical carcinomas and that the development and progression of these alterations is triggered by integration into the host genome.

Carcinoma, Squamous Cell↗
PubMed2000

Thyroid transcription factor-1 is the superior immunohistochemical marker for pulmonary adenocarcinomas and large cell carcinomas compared to surfactant proteins A and B.

AIMS: Antibodies against the thyroid transcription factor-1 (TTF-1) and the surfactant proteins A and B (SPA, SPB) were compared as paraffin-reactive immunohistochemical markers for non-small cell carcinomas of pulmonary origin. METHODS AND RESULTS: We studied 138 carcinomas of pulmonary origin (98 adenocarcinomas, 20 non-neuroendocrine large cell carcinomas, 20 squamous cell carcinomas) and a total of 276 extrapulmonary carcinomas of various primary origins. Using the monoclonal antibody 8G7G3/1, TTF-1 was detectable in 75% of non-mucinous pulmonary adenocarcinomas and in 40% of large cell carcinomas but in only 10% of mucinous adenocarcinomas and not in squamous cell carcinomas. In contrast, both SPA and SPB were positive in only 45% of pulmonary adenocarcinomas and in 10% and in 5% of the large cell carcinomas, respectively. TTF-1 had a specificity of 0.98 for pulmonary carcinomas as 5/7 thyroid carcinomas were the only TTF-1-positive extrapulmonary tumours. Anti-SPB and anti-SPA had specificities of 1. 00 and 0.97, respectively. CONCLUSIONS: The monoclonal antibody 8G7G3/1 against TTF-1 should be the first choice as a component of an antibody panel aiming to prove or to exclude the pulmonary origin of non-mucinous adenocarcinomas and non-neuroendocrine poorly differentiated carcinomas, especially in patients presenting with metastatic carcinomas of unknown primary site.

Adenocarcinoma↗
PubMed2000

Expression of thyroid transcription factor-1 in pulmonary and extrapulmonary small cell carcinomas and other neuroendocrine carcinomas of various primary sites.

AIMS: The thyroid transcription factor-1 (TTF-1) is a highly specific immunohistochemical marker for the identification of pulmonary adenocarcinomas and non-neuroendocrine large cell carcinomas, especially in patients presenting with metastatic carcinomas of unknown primary site. In this study we tested if anti-TTF-1 can also be used to verify a pulmonary origin of neuroendocrine carcinomas, placing emphasis on the discrimination of pulmonary small cell carcinomas (SCCs) from extrapulmonary SCCs and the distinction of SCCs from Merkel cell carcinomas of the skin. METHODS AND RESULTS: We studied 37 pulmonary SCCs, 15 SCCs of extrapulmonary origin, 4 pulmonary large cell neuroendocrine carcinomas (LCNECs), four extrapulmonary LCNECs, six medullary thyroid carcinomas, 16 Merkel cell carcinomas, and a total of 32 carcinoids/low-grade neuroendocrine carcinomas of pulmonary (12 cases) and extrapulmonary (20 cases) origin. Using the commercially available monoclonal antibody 8G7G3/1, TTF-1 was immunohistochemically detectable in 81% of pulmonary SCCs but also in 80% of extrapulmonary SCCs. Furthermore, anti-TTF-1 showed a positive staining in 50% of all pulmonary carcinoids, in one gastric carcinoid, in 2/4 of pulmonary, and 1/4 of extrapulmonary LCNECs. All medullary thyroid carcinomas were also TTF-1-positive. Merkel cell carcinomas were consistently TTF-1-negative. CONCLUSIONS: Our results suggest that in contrast to non-neuroendocrine carcinomas, anti-TTF-1 cannot be used to prove or to exclude a pulmonary origin of SCCs or LCNECs of unknown or uncertain primary site. Therefore, before using anti-TTF-1 as a marker for pulmonary carcinomas one should be sure to have excluded SCC and LCNEC. On the other hand, anti-TTF-1 might be used to specifically discriminate SCCs of various origin from Merkel cell carcinomas.

Antibodies, Monoclonal↗
PubMed2000

Chromosomal alterations in the clonal evolution to the metastatic stage of squamous cell carcinomas of the lung.

Comparative genomic hybridization (CGH) was applied to squamous cell carcinomas (SCC) of the lung to define chromosomal imbalances that are associated with the metastatic phenotype. In total, 64 lung SCC from 50 patients were investigated, 25 each with or without evidence of metastasis formation. The chromosomal imbalances summarized by a CGH histogram of the 50 cases revealed deletions most frequently on chromosomes 1p21-p31, 2q34-q36, 3p, 4p, 4q, 5q, 6q14-q24, 8p, 9p, 10q, 11p12-p14, 13q13-qter, 18q12-qter and 21q21. DNA over-representations were most pronounced for chromosomes 1q11-q25, 1q32-q41, 3q, 5p, 8q22-qter, 11q13, 12p, 17q21-q22, 17q24-q25, 19, 20q and 22q. In ten cases, paired samples of primaries and at least one metastasis were analysed. The comparison revealed a considerable chromosomal instability and genetic heterogeneity; however, the CGH pattern indicated a clonal relationship in each case. The difference in histograms from the metastatic and non-metastatic tumour groups was most useful in pinpointing chromosomal imbalances associated with the metastatic phenotype, indicating that the deletions at 3p12-p14, 3p21, 4p15-p16, 6q24-qter, 8p22-p23, 10q21-qter and 21q22, as well as the over-representations at 1q21-q25, 8q, 9q34, 14q12 and 15q12-q15, occurred significantly more often in the metastatic tumour group. The comparison of the paired samples confirmed these findings in individual cases and suggested distinct genetic changes, in particular the extension of small interstitial deletions, during tumour progression. Importantly, metastasis-associated lesions were frequently detectable in the primary tumour providing a method of identifying patients at risk for tumour dissemination. Individual profiles and histograms are accessible at our web site http://amba.charite.de/cgh.

Carcinoma, Squamous Cell↗
PubMed2000

Modulation of DNA topoisomerase II activity and expression in melanoma cells with acquired drug resistance.

The role of DNA topoisomerases (Topo) IIalpha and IIbeta was investigated in various drug-resistant melanoma cells. Melanoma cells resistant to etoposide, exhibited an up to tenfold reduced Topo II activity corresponding to an increasing degree of drug resistance indicating that modulation of Topo II activity contribute to the drug-resistant phenotype. The reduction of Topo II activity was reflected by decreased nuclear amounts of both Topo II isoforms.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Uroplakin III is a highly specific and moderately sensitive immunohistochemical marker for primary and metastatic urothelial carcinomas.

Uroplakins are specific differentiation products of terminally differentiated superficial urothelial cells. We tested the value of a new commercially available monoclonal antibody against uroplakin III (clone AU 1) as a paraffin-reactive immunohistochemical marker for primary and metastatic urothelial carcinomas. The study cases included 67 urothelial carcinomas of the urinary tract (35 primary tumors, 32 metastases) and 318 nonurothelial carcinomas, as well as 5 benign Brenner tumors and 2 transitional cell carcinomas of the ovaries. Uroplakin III was detected in 21 (60%) of the primary urothelial carcinomas and 17 (53%) of the metastases, resulting in an overall sensitivity of 0.57. The studied Brenner tumors also were immunoreactive for uroplakin III. All other studied carcinomas were consistently uroplakin III-negative (specificity 1.00). We found the new monoclonal antibody AU 1 against uroplakin III to be a highly specific paraffin-reactive immunohistochemical marker for urothelial tumors with a moderate sensitivity for the identification of primary and metastatic urothelial carcinomas.

Aged↗
PubMed1999

Involvement of the c-erbB-2 oncogene product in the EGF-induced cell motility of SK-OV-3 ovarian cancer cells.

The epidermal growth factor (EGF) induces the rapid formation of dendritic processes and the dissociation of SK-OV-3 ovarian cancer cells. The SK-OV-3 cell line is characterized by over-expression of the c-erbB-2 oncogene product (p185(c-erbB-2)). To investigate the role of p185(c-erbB-2) in cell motility, a c-erbB-2-specific single-chain antibody was expressed in SK-OV-3 cells using a retroviral expression vector. Eight individual clones expressing the single chain antibody were isolated. These clones have prominent retention of the cell-surface p185(c-erbB-2). The EGF-induced morphologic changes and cell motility of the single-chain-antibody-expressing clones were strongly inhibited, as observed in cell dissociation and in transmigration experiments. However, the suppression of p185(c-erbB-2) does not inhibit the motility signal elicited by 12-O-tetradecanoyl-phorbol-13-acetate. These data indicate that the c-erbB-2 oncogene product is essential to mediate the motility signal of EGF to SK-OV-3 ovarian cancer cells. The enhancement of tumor-cell motility may be partially responsible for the unfavorable prognosis of ovarian cancer with over-expression of c-erbB-2.

Cell Movement↗
PubMed1999

Atypical multidrug resistance: breast cancer resistance protein messenger RNA expression in mitoxantrone-selected cell lines.

BACKGROUND: Human cancer cell lines grown in the presence of the cytotoxic agent mitoxantrone frequently develop resistance associated with a reduction in intracellular drug accumulation without increased expression of the known drug resistance transporters P-glycoprotein and multidrug resistance protein (also known as multidrug resistance-associated protein). Breast cancer resistance protein (BCRP) is a recently described adenosine triphosphate-binding cassette transporter associated with resistance to mitoxantrone and anthracyclines. This study was undertaken to test the prevalence of BCRP overexpression in cell lines selected for growth in the presence of mitoxantrone. METHODS: Total cellular RNA or poly A+ RNA and genomic DNA were isolated from parental and drug-selected cell lines. Expression of BCRP messenger RNA (mRNA) and amplification of the BCRP gene were analyzed by northern and Southern blot hybridization, respectively. RESULTS: A variety of drug-resistant human cancer cell lines derived by selection with mitoxantrone markedly overexpressed BCRP mRNA; these cell lines included sublines of human breast carcinoma (MCF-7), colon carcinoma (S1 and HT29), gastric carcinoma (EPG85-257), fibrosarcoma (EPF86-079), and myeloma (8226) origins. Analysis of genomic DNA from BCRP-overexpressing MCF-7/MX cells demonstrated that the BCRP gene was also amplified in these cells. CONCLUSIONS: Overexpression of BCRP mRNA is frequently observed in multidrug-resistant cell lines selected with mitoxantrone, suggesting that BCRP is likely to be a major cellular defense mechanism elicited in response to exposure to this drug. It is likely that BCRP is the putative "mitoxantrone transporter" hypothesized to be present in these cell lines.

Antineoplastic Agents↗
PubMed1999

Expression of DNA repair proteins hMSH2, hMSH6, hMLH1, O6-methylguanine-DNA methyltransferase and N-methylpurine-DNA glycosylase in melanoma cells with acquired drug resistance.

Malignant melanoma is well known for its primary unresponsiveness to chemotherapy. The mechanisms conferring this intrinsic resistance are unclear. In this study, we investigated the role of genes involved in DNA repair in a panel of human melanoma cell variants exhibiting low and high levels of resistance to 4 commonly used drugs in melanoma treatment, i.e., vindesine, etoposide, fotemustine and cisplatin. We show that in melanoma cells exhibiting resistance to cisplatin, etoposide and vindesine, the nuclear content of each of the DNA mismatch repair (MMR) proteins hMLH1, hMSH2 and hMSH6 was reduced by 30-70%. A decreased expression level of up to 80% of mRNAs encoding hMLH1 and hMSH2 was observed in drug-resistant melanoma cells selected for cisplatin, etoposide and fotemustine, while vindesine-selected cells showed only moderate reduction. In melanoma cells that acquired resistance to fotemustine, the amount of nuclear MMR proteins was nearly unaltered, whereas the activity of O6-methylguanine-DNA methyltransferase (MGMT) was considerably enhanced. Activity of N-methylpurine-DNA glycosylase (MPG) was not significantly altered in any of the drug-resistant melanoma cells. Our data indicate that modulation of both MMR components and MGMT expression level may contribute to the drug-resistant phenotype of melanoma cells.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Increased expression of epidermal fatty acid binding protein, cofilin, and 14-3-3-sigma (stratifin) detected by two-dimensional gel electrophoresis, mass spectrometry and microsequencing of drug-resistant human adenocarcinoma of the pancreas.

In order to study possible mechanisms leading to chemoresistance in pancreatic adenocarcinoma we examined the global protein expression of pancreatic cancer cells in vitro. We used a cell culture model derived from the adenocarcinoma of the pancreas (EPP85-181P). A classical multidrug-resistant subline, EPP85-181RDB, selected in presence of daunorubicin, and an atypical multidrug-resistant cell variant, EPP85-181RNOV, selected in presence of mitoxantrone, were analyzed using two-dimensional electrophoresis. After staining and image analysis, spots of interest were isolated using preparative two-dimensional electrophoresis and subjected to mass spectrometry and microsequencing. Three proteins, E-FABP, cofilin, and 14-3-3-sigma (stratifin), were overexpressed in chemoresistant cell lines. Cofilin was present in both multidrug in chemoresistant cell lines. Cofilin was present in both multidrug-resistant cell lines. E-FABP and 14-3-3-sigma (stratifin) was found to be overexpressed only in the mitoxantrone-selected atypical multidrug-resistant cell line. The possible significance of these findings is discussed.

14-3-3 Proteins↗
PubMed1999

Search for novel proteins involved in the development of chemoresistance in colorectal cancer and fibrosarcoma cells in vitro using two-dimensional electrophoresis, mass spectrometry and microsequencing.

In search of novel mechanisms that may lead to the development of chemoresistance of malignant tumors of the large bowel we used two-dimensional electrophoresis to identify proteins that were overexpressed in colorectal and fibrosarcoma cell lines that were resistant towards mitoxantrone. This cytostatic drug is known to lead to atypical multidrug resistance, i.e., the classical mechanism of multidrug resistance (MDR) accompanied by the overexpression of P-glycoprotein (P-gp) is ineffective. Using mass spectrometry and microsequencing we found adenine phosphoribosyl transferase and breast cancer specific gene 1 (BCSG1) overexpressed in the resistant colorectal tumor cell line. In the chemoresistant fibrosarcoma cell line we found two proteins that were overexpressed. One was identified as Rho-guanine dinucleotide phosphate (Rho-GDP) dissociation inhibitor and the other had sequence homologies with yeast protein yer-7. The putative role of these proteins is discussed.

Antineoplastic Agents↗
PubMed1999

Involvement of the DNA mismatch repair system in antineoplastic drug resistance.

Different types of antineoplastic drugs, such as the alkylating agents busulfan, N-methyl-N'-nitro-N-nitrosoguanidine, N-methyl-N-nitrosourea, procarbazine and temozolomide, the antimetabolites, mercaptopurine and 6-thioguanine, the platinum compounds carboplatin and cisplatin, the anthracycline doxorubicin and the epipodophyllotoxine etoposide act by damaging DNA directly or indirectly. Increasing evidence has shown that tumours could acquire resistance to these drugs by loss of DNA-mismatch repair (MMR) activity. This phenomenon is caused by a decreased MMR-dependent stimulation of signal-transduction pathways causing programmed cell death. Simultaneously, the mutation rate in MMR-deficient tumours is increasing, which could lead to additional secondary drug/resistance phenotypes to other antineoplastic agents. In addition to this, an enhanced mutation rate may contribute to increased phenotypic variation and therefore the clinical aggressiveness of primary tumours and their metastases.

Animals↗
PubMed1999

Effect of follicular cells on calcitonin gene expression in thyroid parafollicular cells in cell culture.

Expression of calcitonin (CT) gene in thyroid parafollicular cells involves alternate formation of CT mRNA or CGRP mRNA. High amounts of CT mRNA are formed only in thyroid gland and formation of CGRP mRNA dominates in the remaining organs. Apart from paracrine and endocrine factors, mRNA formation on the CT gene seems to be affected also by direct contacts with other cells present in the thyroid gland, in which parafollicular cells are located next to follicular cells. The present study aimed at examining whether thyroid follicular cells affect formation of mRNAs for CT and CGRP in parafollicular cells. The studies were performed in cell cultures. A parafollicular cell line (TT cells) and a follicular cell line (F6BTY cells) served as the experimental model. For comparison, co-cultures with fibroblasts, 3T3 cells, and malignant melanoma, MM cells, were also examined. CT gene expression was examined at the level of mRNAs (in situ hybridization and morphometric studies) and at the level of hormones (immunocytochemistry, morphometric studies and radioimmunological estimation of hormone levels in the medium). The immunocytochemical and hybridocytochemical studies, in line with morphometry studies, demonstrated that F6BTY and 3T3 cells were capable of affecting mRNA production for CT and CGRP and that they changed the ratio of CGRP/CT secretion by TT cells, as a sequel of contact between the two cell types and due to mediation of secreted substances. On the other hand, the malignant melanoma MM cells showed no effect on the secretion ratio. Our study seems to indicate that control of mRNA formation from CT gene may involve not only humoral factors but also direct contacts with other cells, which may explain differences in expression of the gene between cells localized in different organs.

Calcitonin↗