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C Welter

Publications and source records attributed to C Welter.

At least 55 records · Page 3Linked to original sources
PubMed1995

Differential expression of the pS2 protein in the human prostate and prostate cancer: association with premalignant changes and neuroendocrine differentiation.

The distribution of the estrogen inducible pS2 protein was investigated in benign and malignant prostate tissue by the avidin-biotin complex method. Prostate tissue obtained from 20 patients without clinical and histological evidence of malignant disease consistently lacked pS2 immunoreactivity. Conversely, nonneoplastic tissue from 36 total prostatectomies with locally advanced prostate cancer showed a variable degree of pS2 reactivity in normal or hyperplastic glands and in prostatic intraepithelial neoplasia (PIN) adjacent to the cancerous lesions. This suggests that the pS2 gene expression detected in nonmalignant tissue may be related to early premalignant changes of prostate glands harboring significant carcinomas. In prostate cancer the pS2 protein was detected in close association with neuroendocrine (NE) differentiation as assessed by Chromogranin A (Chr A) immunoreactivity. Double labeling techniques showed that pS2 immunoreactivity recognizes both endocrine (Chr A-positive) and adjacent exocrine (Chr A-negative) cell types within NE foci. Whereas pS2 expression was consistently confined to NE differentiation in untreated tumors, carcinomas that relapsed after hormonal therapy showed increased pS2 immunoreactivity, even in the absence of NE features. The differential expression of the pS2 peptide in nonneoplastic tissue from patients with and without malignant disease indicates that pS2 immunohistochemistry may be useful in the diagnostic evaluation of negative biopsy specimens. Furthermore, the results suggest that the immunohistochemical spectrum of pS2 in prostate cancer may include endocrine differentiated and presumably related cell populations.

Carcinoma↗
PubMed1994

Presence of regulatory sequences within intron 4 of human and murine c-myb genes.

The molecular mechanisms that modulate c-myb mRNA transcription in hematopoietic cells appear to involve intron regulatory sequences. We have characterized the fourth of ten introns from both human and murine c-myb genes in regard to nucleotide sequence and specific protein binding. For this approach complete genomic c-myb intron 4 fragments were isolated from mouse and human DNA using PCR amplification with flanking exon-primers derived from the mouse gene. Comparison of the obtained sequences revealed strong homology between the two species. Using crude nuclear protein extracts from mouse and human myb expressing cells (70Z/3B; Molt4) and gel shift experiments we found specific protein interaction for both introns and to determine the protein binding site in detail, we performed DNase I footprinting. Our results indicate that the binding factor is absent in control cell lines without c-myb transcriptional activity, suggesting a possible positive regulatory function of the DNA-protein complex. To confirm these findings we introduced the human c-myb intron 4 DNA sequence into the EcoRI site of the pCAT-Promoter plasmid and transfected Molt4 cells with this chimeric construct. The transient expression studies revealed that intron 4 sequences possess enhancer activity. Thus, we have demonstrated that intron 4 sequences can be important for the regulation of c-myb proto-oncogene expression.

Animals↗
PubMed1994

Phosphorylation of nm23/nucleoside diphosphate kinase by casein kinase 2 in vitro.

We have investigated phosphorylation of human nucleoside diphosphate kinase (NDPK) and of homologous NDPK from different species by human casein kinase 2 (CK-2). The human NDPK isotypes A and B were phosphorylated by CK-2 in vitro both when the purified proteins and total lysate of HL-60 leukemia cells were used. The homologous NDPK's from Yeast and E. coli were also substrates for CK-2 in vitro, but not Drosophila NDPK. Phosphorylation of all NDPK types by the CK-2 holoenzyme was entirely polyamine-dependent. The CK-2 phosphorylation site in human NDPK A, that was about 2.5 times stronger phosphorylated than was the B isotype, was tentatively assigned to Ser-122. The location of the corresponding residue in the 3D-structure of the 80% homologous Drosophila NDPK suggests that its phosphorylation may directly influence substrate binding and/or catalysis.

Amino Acid Sequence↗
PubMed1994

Expression pattern of breast-cancer-associated protein pS2/BCEI in colorectal tumors.

Recently, several carcinomas of the gastrointestinal tract were tested for pS2/BCEI activity, a gene isolated from breast-cancer cells and coding for a small secreted peptide. In the latter tumors, its activity is under estrogen control; surprisingly, it was also found expressed in carcinomas of the stomach, biliary tract and pancreas. We have now investigated the expression of this gene in 64 colorectal carcinomas, 31 adenomas and 13 polyps in comparison with their matrix tissues by applying molecular (RNA analysis) and immunohistochemical (pS2 antibody) techniques. Positive pS2 immunostaining (ranging from focal to strong immunoreaction) was noted in 89% of human colon cancers, while 11% remained negative. Furthermore, all 40 transitional mucosae were strongly positive, whereas normal mucosa was negative. Of hyperplastic polyps, 68.2% displayed a significant immunoreaction, and 80.6% of adenomas were focally positive. Finally, 6 out of 16 cases showed significant pS2 transcription in Northern blot analysis. These data clearly indicate that the breast-cancer-associated pS2 protein also plays an as yet undetermined role in the tumorigenesis of human colorectal carcinomas.

Breast Neoplasms↗
PubMed1994

Isolation and characterization of the human genomic locus coding for the putative metastasis control gene nm23-H1.

Nm23-H1 gene expression is inversely correlated with tumor metastatic potential in certain tumors, including melanomas, breast carcinomas, and hepatocellular carcinomas. Using nm23-H1 c-DNA primer and genomic polymerase chain reaction (PCR) amplification, we purified three PCR fragments (one of 4kb and two of 2 kb) covering the whole human genomic locus of the gene (8.460bp). We recombined the PCR products into pUC18 and produced a restriction map to perform subcloning. Complete sequencing of genomic PCR fragments, including the whole coding region of nm23-H1, revealed that the gene consists of five exons and four introns spanning 8.5kb. A sequence homology analysis between human nm23-H1 and the homolog gene of the rat (NDP-K beta) shows that exon-intron boundaries are well conserved between these two species.

Amino Acid Sequence↗
PubMed1994

Squamous cell carcinoma of the lung: does the nm23 gene expression correlate to the tumor stage?

We examined the nm23 gene activity in 30 human squamous cell carcinomas of the lung using the Northern blot analysis. Matched healthy lung tissue was available from 10 patients. 26 tumor samples were obtained after resection treatment between 1986 and 1990, 4 additional samples of advanced stages from autopsy. We found a significant increase of nm23 expression towards advanced stages of squamous cell carcinoma (IIIa vs. I: p < 0.015, IV vs. II: p < 0.043, IV vs. I: p < 0.043). Furthermore in stage I and II, poorly differentiated squamous cell carcinomas contained significantly more nm23 mRNA than did moderately differentiated ones (p < 0.027). We could also demonstrate an inverse correlation between the levels of nm23 mRNA and disease-free survival after resection treatment (p < 0.016, chi 2-test for trend). Thus the nm23-gene activity correlates to the tumor stage and the grade of differentiation of the squamous cell carcinoma of the lung, and is therefore of prognostic relevance. It might be possible to describe the biological behaviour of the individual tumor more accurately by the additional measurement of the nm23 mRNA.

Carcinoma, Squamous Cell↗
PubMed1994

PCR expression analysis of the estrogen-inducible gene BCEI in gastrointestinal and other human tumors.

A polymerase chain reaction (PCR) assay was developed to test for tumor cell specific expression of the BCEI gene. This new marker gene, reported at first for human breast cancer, was found specifically active in various gastrointestinal carcinomas by previously applying immunohistochemistry and RNA (Northern blot) analysis. Presently, by using reverse transcription-PCR analysis, a series of primary tumor tissues and established tumor cell lines were tested for BCEI transcription. This approach was compared to immunostaining achieved by an antibody directed against the BCEI gene's product. The result demonstrate the superior sensitivity of PCR by indicating the gene's expression in cases where immunohistochemical testing remained negative.

Base Sequence↗
PubMed1993

High levels of nm23-H1 and nm23-H2 messenger RNA in human squamous-cell lung carcinoma are associated with poor differentiation and advanced tumor stages.

Expression of the candidate metastasis-suppressor gene nm23-H1 has been shown to correlate inversely with metastatic potential in some human tumors, but not in all. Until now, few studies have been carried out on the activity of the homologous nm23-H2 gene in human cancer. No nm23 transcription studies exist for human lung cancer so far. To determine whether the nm23 genes could have a metastasis-suppressor function in non-small-cell lung carcinoma (NSCLC), pulmonary sarcoma and carcinoids, we analysed both nm23-HI and nm23-H2 mRNA levels in 37 tumor samples obtained from patients who underwent potentially curative resection between 1986 and 1990, and in 4 metastatic tumors obtained from autopsy. As compared to corresponding healthy lung parenchyma, both nm23-HI and nm23-H2 transcript levels were elevated in 37 of 41 tumors. The increases in nm23 mRNA expression were stronger in advanced stages of squamous-cell carcinoma, large-cell carcinoma, sarcoma and carcinoids than in early stages of the respective tumor types. Within stages I and II of squamous-cell carcinoma, significantly higher nm23 mRNA levels were found in poorly differentiated tumors than in moderately differentiated ones. Moreover, an inverse correlation between nm23 expression and disease-free survival of the patients was observed. In conclusion, our results indicate that the increased nm23 expression in the analysed tumors is not consistent with the proposed metastasis-suppressor function, but the 2 nm23 genes nevertheless may be implicated in the mechanism of tumor progression.

Adenocarcinoma↗
PubMed1993

Retrospective analysis of prognostic significance of the estrogen-inducible pS2 gene in male breast carcinoma.

BACKGROUND: The estrogen-inducible pS2 gene, originally isolated from a breast cancer cell line, is correlated with hormone-dependent female breast tumors and its expression is associated with longer overall and disease-free survival. METHODS: The authors have investigated 38 samples of carcinomas of the male breast for pS2 expression by using a monoclonal antibody. The immunostaining was compared with clinical data, in particular, to the progesterone receptor status, to assess a possible prognostic value of this parameter. RESULTS: Although most cases (27 of 38) were immunopositive (i.e., above the 5th percentile of immunoreactive cells), no correlation with tumor grade and survival was notable. CONCLUSIONS: Therefore, on the contrary to the situation in female breast cancer, pS2 activity failed to constitute a new prognostic parameter in male breast carcinomas.

Adult↗
PubMed1993

A rapid method to determine the orientation of blunt end ligated polymerase chain reaction products.

Subcloning of polymerase chain reaction (PCR) fragments is often performed via blunt end ligation after previous Klenow fragment exonuclease treatment. Since insert-specific primers are at hand from the original amplification step, we used a simple PCR-based assay to determine the insert orientation of the recombinants. After purification of enriched plasmids, small aliquots were tested performing standard PCR reactions using a plasmid primer directed towards the cloning site and one of the insert specific primers, respectively. Only the distant insert primer yields a PCR product which can be visualized after gel electrophoresis. In this way both the insert orientation in the vector and the correct size of the cloned fragment is determined rapidly without sequencing or restriction fragment analysis.

Animals↗
PubMed1993

Telomeric associations and loss of telomeric DNA repeats in renal tumors.

In a series of cytogenetically analyzed renal tumors of different histological types (chromophobe carcinoma, clear-cell carcinoma, chromophilic carcinoma, and oncocytoma) and normal renal tissue, the length of the telomeric DNA repeats was assessed using a (TTAGGG)3 oligonucleotide probe. A strong correlation was noted between pronounced telomere shortening and the appearance of telomeric associations of chromosomes. These data suggest an etiologic role of the loss of telomeric DNA repeats in the formation of telomeric associations and a possible involvement of this mechanism in the pathogenesis of chromosome aberrations in human tumors.

Adenocarcinoma↗
PubMed1993

Clonal chromosome aberrations in cell cultures of synovial tissue from patients with rheumatoid arthritis.

Cytogenetic analysis of primary cell cultures and/or passages 1-3 of synovial tissue from seven patients with rheumatoid arthritis was performed. As the only recurrent chromosome aberration, trisomy 7 was found in six of seven cultures. In four cultures, trisomy 7 occurred as a clonal change in up to 20% of the analyzed cells, with an increase of the proportion of cells with +7 with the duration of the in vitro culture. Apart from this recurrent change, a variety of partly clonal, partly nonclonal numerical and structural chromosome aberrations were observed in all cases. These findings support the view that clonal chromosome aberrations may play a role in the pathogenesis of invasive growth of the synovial tissue in rheumatoid arthritis although the localized synovial hyperproliferation is not a true neoplastic process.

Arthritis, Rheumatoid↗
PubMed1993

Expression of the breast cancer-associated protein pS2 in adenosquamous carcinomas of the gastrointestinal tract.

The breast cancer-associated protein pS2 is also present in many human gastrointestinal tumors. In contrast to breast carcinomas, gastrointestinal tumors do not express estrogen receptors, indicating that the expression of pS2 is not estrogen-dependent. The pS2 expression was analyzed in 14 adenosquamous tumors of the human gastrointestinal tract. The aim was to investigate if the cell type specific localization of pS2 was limited to the glandular part. The data clearly confirm such a specific compartmentation of the pS2 expression, suggesting pS2 to be a secreted protein. Due to the specific expression, pS2 may become a new and useful diagnostic marker of adenocarcinoma.

Adenocarcinoma↗
PubMed1992

DNA-protein interaction analysis using polyacrylamide gel electrophoresis and a simple and sensitive UV crosslinking procedure.

A simple and reproducible technique for DNA-protein interaction analysis is described using UV crosslinking and polyacrylamide gel electrophoresis, leading to visualization of the complexes as distinct and strong signals. It avoids incorporation of bromodeoxyuridine (BrdU) into DNA and requires no special equipment. It was successfully applied to an oligonucleotide sequence from within the first intron of the mouse myb proto-oncogene and nuclear extracts from a myb-expressing cell line.

Base Sequence↗
PubMed1992

A two-colour technique for chromosome in situ hybridization in tissue sections.

By extending non-isotopic in situ hybridization of DNA probes (targeted to metaphase chromosomes or interphase nuclei) to hybridization using tissue sections, additional topological information on the DNA structure and specific alterations can be obtained. We have established a method for the application of two different, chromosome-specific probes labelled with two colour dyes allowing simultaneous detection of two-colour signals. This method was tested in and is applicable to tissue sections of various origins. To demonstrate its sensitivity, prostate carcinomas (either as cryosections or as sections from paraffin blocks) were investigated for the presence or absence of chromosomes 1 and Y. The technique presented here, comparable to immunohistochemical staining, is particularly useful for routine application in diagnostic laboratories and testing of fresh or archival material.

Carcinoma↗
PubMed1992

Assignment of the gene for human spasmolytic protein (hSP/SML1) to chromosome 21.

A human cDNA corresponding to the porcine pancreatic spasmolytic protein (PSP) was isolated, and the recombinant clone was originally termed hSP for human spasmolytic protein. Later, the term SML1 for spasmolysin was suggested for the human gene. This protein shows a remarkable sequence homology to pS2, a protein coded by an estrogen-induced gene isolated from the breast carcinoma cell line MCF-7. Although, at the DNA level, the gene sequences pS2 and hSP/SML1 display insufficient homology for cross-hybridization, their expression in tumor cells occurs with remarkable coordination. The human pS2 gene sequence has been assigned to chromosome 21, and we have therefore attempted to map the hSP/SML1 gene by using cDNA and Southern blotting of genomic DNAs from a panel of human-rodent somatic cell hybrids carrying different complements of human chromosomes. Interestingly, the hSP/SML1 gene is also localized on chromosome 21.

Blotting, Southern↗