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R Poulsom

Publications and source records attributed to R Poulsom.

At least 55 records · Page 3Linked to original sources
PubMed1999

The cloning, mapping and expression of a novel gene, BRL, related to the AF10 leukaemia gene.

The MLL gene is reciprocally translocated with one of a number of different partner genes in a proportion of human acute leukaemias. The precise mechanism of oncogenic transformation is unclear since most of the partner genes encode unrelated proteins. However, two partner genes, AF10 and AF17 are related through the presence of a cysteine rich region and a leucine zipper. The identification of other proteins with these structures will aid our understanding of their role in normal and leukaemic cells. We report the cloning of a novel human gene (BRL) which encodes a protein containing a cysteine rich region related to that of AF10 and AF17 and is overall most closely related to the previously known protein BR140. BRL maps to chromosome 22q13 and shows high levels of expression in testis and several cell lines. The deduced protein sequence also contains a bromodomain, four potential LXXLL motifs and four predicted nuclear localization signals. A monoclonal antibody raised to a BRL peptide sequence confirmed its widespread expression as a 120 Kd protein and demonstrated localization to the nucleus within spermatocytes.

Amino Acid Motifs↗
PubMed1999

Identification by differential display of a protein phosphatase-2A regulatory subunit preferentially expressed in malignant melanoma cells.

We described the occurrence of 4 transcripts differentially displayed between syngeneic murine B16F10 (metastatic melanoma) and Melan-a (immortalised melanocytes) cell lines. We now report that one such transcript, which is B16F10-specific, represents a protein phosphatase-2A B' regulatory subunit. No expression of this transcript was detected in the weakly metastatic B16F1 by Northern blotting. Moreover, the transcript was not expressed by spontaneously immortalised, non-tumorigenic, melanocytes (Melan-Ab and Melan-a2), nor was it expressed by ras-transformed, tumourigenic melanocytes (Melan-Ab-LTR-ras). Cloning of the 5'-end region of this transcript (termed band 8A) from B16F10 cells revealed an intracisternal A-particle insertion, including the long terminal repeat region, which could account for the observed high expression in B16F10 cells. Single cell clones of B16F10 manifested an experimental metastasis capacity, which correlated with band 8A expression with the lowest expressors being least metastatic. The human homologue of the B' regulatory subunit, B56gamma, is expressed preferentially at the mRNA level in human melanoma cell lines compared with normal epidermal melanocytes. In situ hybridisation studies on human clinical samples detected high expression of this gene in a number of malignant melanomas. Our results imply strongly that this protein phosphatase-2A regulatory subunit may have a role in melanoma tumour progression.

Animals↗
PubMed1999

A novel gene (PLU-1) containing highly conserved putative DNA/chromatin binding motifs is specifically up-regulated in breast cancer.

A novel human gene (PLU-1) has been identified which shows a highly restricted expression in normal adult tissues but which is consistently expressed in breast cancers. A fragment of the PLU-1 cDNA was identified by differentially screening a fetal brain library with cDNAs prepared from ce-1 cells (a human mammary epithelial cell line overexpressing c-ErbB2) treated or untreated with the antibody 4D5, which inhibits c-ErbB2 phosphorylation. Clones covering the full cDNA sequence of 6.4 kilobases were isolated from a breast cancer cDNA library. Although expression of PLU-1 in ce-1 cells is regulated by signaling from c-ErbB2, the gene is expressed in all the breast cancer cell lines examined, in cells cultured from primary breast cancers, and in the invasive and in situ components of primary breast cancers. Translation of the open reading frame predicts a protein of 1544 amino acids, which contains three PHD/LAP motifs, a specific DNA-binding domain found in a Drosophila protein (dri) and novel domains showing extensive homology with other human and non human gene products. Transient transfection of cell lines with MYC-tagged PLU-1 showed the protein to be localized in the nucleus and associated with discrete foci. The presence of the dri motif and PHD/LAP fingers together with the clear nuclear localization and consistent expression in breast cancers, suggest a role for PLU-1 in regulating gene expression in breast cancers.

Amino Acid Sequence↗
PubMed1999

The mucous neck cell in the human gastric corpus: a distinctive, functional cell lineage.

There is considerable debate about whether the mucous neck cell (MNC) in the mucosa of the gastric corpus is merely a transit cell population, intermediate between gastric stem cells and the differentiated zymogenic (chief or peptic) cell lineages, or has distinct functions of its own. To cast light on these possibilities, the secretory phenotype of the MNC has been examined. Archival gastric body samples from non-ulcer dyspepsia biopsies and gastrectomies performed for peptic ulcer disease were stained with antibodies to the trefoil peptides TFF1/pS2 and TFF2/SP, pancreatic secretory trypsin inhibitor (PSTI), epidermal growth factor (EGF) and its receptor (EGFR), and to the MUC1 gene product--HMFG2. Human MNCs express PSTI, TFF1/pS2, TFF2/SP, and EGF proteins, while rat MNCs express TFF2/SP; the mucin contained in the MNCs is diastase/periodic acid Schiff (D/PAS)-positive and stains with human milk fat globulin (HMFG2). The canaliculi but not the cytoplasm of adjacent parietal cells were also decorated focally by D/PAS, by HMFG2, and by antibodies to TFF2/SP and TFF1/pS2. These findings favour the hypothesis that MNCs have a defined phenotype and are thus a separate and distinct cell lineage, secreting a number of luminally-active peptides which protect the gastric mucosa, and in particular the adjacent parietal cells, from the effects of secreted gastric acid. Moreover, a considerable degree of similarity in secretory profile is noted between MNCs and the so-called 'reparative lineages' in the gut--the ulcer-associated cell lineage (UACL) and hyperplastic polyp epithelium. If, on the other hand, the MNCs are indeed a transit population differentiating into zymogenic or peptic cells, then it is clear that having differentiated into one secretory phenotype producing a range of peptides, the MNC then proceeds to differentiate into a cell with a totally different secretory phenotype, a phenomenon unique in gastrointestinal cell lineage relationships.

Animals↗
PubMed1999

Up-regulation of macrophage wnt gene expression in adenoma-carcinoma progression of human colorectal cancer.

Defects in the APC-beta-catenin pathway are common in colon cancer. We investigated whether aberrant regulation of upstream ligands stimulating this pathway occur in colon cancer. Using RNAase protection analysis, six out of eight wnt genes were expressed in 14 matched cases of normal, adenomatous and malignant colorectal tissues. Wnt 2 and wnt 5a were significantly up-regulated in the progression from normal through adenoma to carcinoma. Transcripts for wnts 4, 7b, 10b and 13, but not wnt 2 and wnt 5a were detected in several colorectal cell lines. In situ hybridization demonstrated that wnt 2 and wnt 5a transcripts were mainly in the lamina propria/stroma region with labelling predominantly in macrophages. Immunostaining with CD68 confirmed the wnt-expressing cells as macrophages. These results show a major difference in wnt expression in colon cancer compared to colon adenomas and suggest stromal wnt expression may play a role in tumour progression.

Adenocarcinoma↗
PubMed1999

Trefoil peptides and surgical disease.

BACKGROUND: Trefoil peptides are a family of small proteins that are expressed in a site-specific fashion by certain epithelial tissues. These peptides appear to be important in mucosal healing processes and in neoplastic disease. METHODS: This manuscript reviews the relevant literature obtained by an extensive text word search of the Medline database and a manual search of references from the articles identified. RESULTS AND CONCLUSION: Trefoil peptides are aberrantly expressed by a wide range of human carcinomas and gastrointestinal inflammatory conditions. They impart protection from injury to the gastrointestinal mucosa by possible interaction with mucin glycoproteins. Trefoil peptides influence epithelial cell migration and mucosal restitution following injury. In the future, serum levels of trefoil peptides might be used as markers for both neoplastic and inflammatory diseases. In addition, novel therapies based on such peptides might be used for gastrointestinal inflammatory conditions and to accelerate repair of the gastrointestinal mucosa after surgery.

Biomarkers↗
PubMed1999

An alpha2,3 sialyltransferase (ST3Gal I) is elevated in primary breast carcinomas.

The MUC1 mucin is expressed on the luminal surface of most simple epithelial cells but in carcinomas, especially those of the breast and ovary, MUC1 is upregulated and aberrantly glycosylated. MUC1 contains a large amount of O-linked glycans which, in the mucin expressed by normal mammary epithelial cells, consist mainly of core 2 based structures carrying polylactosamine chains. However, the mucin expressed by breast carcinomas has shorter side-chains, often consisting of sialylated core 1 (Galbeta1-3GalNAc). in situ hybridization of primary breast tissue showed that a sialyltransferase (ST3Gal I), responsible for adding sialic acid to core 1 thereby terminating chain extension, is elevated in primary breast carcinomas when compared to normal or benign tissue. Furthermore, the level of mRNA expression encoding ST3Gal I is correlated to the intensity of staining seen with the antibody SM3, which specifically recognises underglycosylated, tumour associated MUC1. Thus, the aberrant glycosylation of MUC1 seen in breast carcinomas appears to be due, at least in part, to the elevation of ST3Gal I.

Breast Neoplasms↗
PubMed1999

Trefoil peptides.

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Growth Substances↗
PubMed1999

Identification of a metaplastic cell lineage associated with human gastric adenocarcinoma.

Metaplastic cell lineages arising in response to chronic injury are precursors for the evolution of dysplasia and adenocarcinoma. Although a subtype of intestinal metaplasia has been associated with gastric adenocarcinoma, the link between this lineage and the evolution of gastric adenocarcinoma has remained unclear. Wang et al (1998) have reported that an aberrant metaplastic cell lineage with morphological characteristics similar to Brunner's glands of the duodenum develops in the fundic mucosa of mice infected with Helicobacter felis. This metaplastic lineage expresses the trefoil peptide spasmolytic polypeptide (SP). Given the epidemiological association of Helicobacter species infection with gastric cancer, we hypothesized that this SP-expressing metaplastic (SPEM) lineage may represent a precursor to or appear commensurate with gastric adenocarcinoma. The SPEM lineage was present in 68% of fundic biopsies from patients with fundic Helicobacterpylori-associated gastritis, but was absent in biopsies of fundic mucosa from patients without H. pylori infection. In a review of archival samples from 22 resected gastric adenocarcinomas, we found the SPEM lineage in 91% of cases, typically located in mucosa adjacent to the carcinoma or areas of dysplasia. Importantly, 59% of resections showed SP immunoreactivity within dysplastic cells. These data indicate a strong association of the SPEM lineage with both chronic H. pylori infection and gastric adenocarcinoma.

Adenocarcinoma↗
PubMed1998

Interactions between stromal cell--derived keratinocyte growth factor and epithelial transforming growth factor in immune-mediated crypt cell hyperplasia.

Immune reactions in the gut are associated with increased epithelial cell proliferation. Here we have studied the role of keratinocyte growth factor (KGF; FGF7) and transforming growth factor-alpha (TGF-alpha) in the epithelial cell hyperplasia seen in explants of fetal human small intestine after activation of lamina propria T cells with the superantigen Staphylococcus aureus enterotoxin B (SEB). After the addition of SEB to the explants there is a 10-fold increase in KGF mRNA by 72 h of culture. KGF transcripts were abundant in the lamina propria using in situ hybridization and the culture supernatants contained elevated amounts of KGF protein. SEB had no direct effect on KGF mRNA and protein production by cultured lamina propria mesenchymal cells, but both were upregulated by TNF-alpha. Accompanying the increase in KGF there was also an increase in TGF-alpha precursor proteins in the culture supernatants and the phosphorylated form of the EGFR receptor was also detected in the tissue. Increased TGF-alpha precursor proteins were also detected in the supernatants of control explants stimulated with KGF alone. The direct addition of KGF and TGF-alpha enhanced epithelial cell proliferation and antibodies against KGF and TGF-alpha partially inhibited SEB-induced crypt hyperplasia. These results suggest molecular cross-talk between the KGF/KGFR and the TGF-alpha/EGFR in immune-mediated crypt cell hyperplasia.

Drug Interactions↗
PubMed1998

Expression of oestrogen receptor and oestrogen-inducible genes pS2 and ERD5 in large bowel mucosa and cancer.

Since there is a preponderance of large bowel cancer in males, both in humans and in experimental models, and hormone replacement therapy is protective, a role for sex steroid hormones in the pathogenesis of this neoplasm seems likely. Evidence of functional oestrogen receptor has been looked for in large bowel mucosa and cancer. Expression of oestrogen receptor, and of the oestrogen-inducible receptor-associated genes pS2 and ERD5, was sought. Oestrogen receptor mRNA was detected in cancers and paired normal mucosae in equal amounts. In situ hybridization identified stromal cells above the muscularis mucosae that were positive for oestrogen receptor mRNA. pS2 mRNA was also detected, with a signal intensity significantly higher in normal mucosa compared with cancers, whereas the reverse was seen with ERD5 mRNA levels. pS2 and ERD5 were expressed in epithelium, with the former in a greater amount in distal colon and rectum than proximal colon. Although oestrogen-inducible and receptor-associated genes are expressed in large bowel mucosa, their expression does not correlate with oestrogen receptor.

Aged↗
PubMed1998

Expression of the c-erbB-4/HER4 protein and mRNA in normal human fetal and adult tissues and in a survey of nine solid tumour types.

The c-erbB-4/HER4 receptor belongs to the family of the type I growth factor receptors. Mouse monoclonal antibodies have been raised to the cytoplasmic domain of the c-erbB-4 receptor and characterized; the antibody HFR-1 has been used to determine the pattern of expression of the c-erbB-4 protein immunohistochemically in formalin-fixed, paraffin-embedded adult and fetal tissues. The expression of c-erbB-4 mRNA was determined by using 35S-labelled riboprobes and tissue in situ hybridization. c-erbB-4 is widely expressed in many adult and fetal tissues, including the lining epithelia of the gastrointestinal, urinary, reproductive, and respiratory tracts, as well as the skin, skeletal muscle, circulatory, endocrine, and nervous systems. The developing brain and heart notably express high levels of this receptor. The pattern of c-erbB-4 protein expression is also reported in a survey of common solid human cancers. Loss of expression was noted in 40-80 per cent of adenocarcinomas and up to 100 per cent of squamous cell carcinomas, whereas overexpression was observed in about 10-20 per cent of adenocarcinomas and astrocytomas. In general, the pattern of c-erbB-4 expression in normal tissues and cancers suggests that it tends to be associated with the differentiated compartment.

Adenocarcinoma↗
PubMed1998

Invasive lobular and invasive ductal carcinoma of the breast show distinct patterns of vascular endothelial growth factor expression and angiogenesis.

Angiogenesis is essential for tumour growth and important in tumour metastasis and prognosis. Vascular endothelial growth factor (VEGF) stimulates endothelial proliferation in vitro and angiogenesis in vivo. VEGF expression has been correlated with high vascularity in tumours, including carcinoma of the breast. This study investigated VEGF expression and vascularity of invasive lobular (n = 10) and invasive ductal carcinoma (n = 28), and pure ductal carcinoma in situ of the breast (n = 33). VEGF protein expression was studied with immunohistochemistry and VEGF mRNA with in situ hybridization. Vascular density was assessed on sections stained for von Willebrand factor. There was more expression of both VEGF protein (P = 0.006) and mRNA (P = 0.002) in invasive ductal than in invasive lobular carcinoma. VEGF protein (rs = 0.32, P = 0.047) and mRNA (rs = 0.56, P = 0.04) correlated with vascular density in invasive ductal carcinoma. In invasive lobular carcinoma, vascular density did not correlate with VEGF mRNA (rs = 0.15, P = 0.35) and was inversely related to VEGF protein (rs = -0.57, P = 0.04). There were no significant differences in vascular density between the two types of invasive carcinoma, suggesting that VEGF is important in angiogenesis in invasive ductal carcinoma, but that other angiogenic factors are important in invasive lobular carcinoma. Although VEGF protein was frequently expressed in ductal carcinoma in situ, no relationship was found between VEGF and the two patterns of angiogenesis previously described.

Breast↗
PubMed1998

MT1-MMP and MMP-2 mRNA expression in human ovarian tumors: possible implications for the role of desmoplastic fibroblasts.

Expression of activated MMP-2 (72 kDa type IV collagenase) is highly associated with the malignant phenotype in adenocarcinomas, but predominant expression of the mRNA appears to be in stromal cells. MT1-MMP (membrane type 1-matrix metalloproteinase) is implicated in tumor-epithelial cell surface activation of latent pro-MMP-2, indicating a mechanism for tumor-stromal interaction in invasion. We determined the relative mRNA distribution of these MMPs in human ovarian tumors with a view to analyzing potential variations in the epithelial-mesenchymal interactions dictating ovarian tumor cell spread. In situ hybridization using 35S-labeled riboprobes was used to analyze 33 human ovarian tumors and mouse xenografts of human ovarian (DOV 13, SKOV3) and breast (MCF 7) tumor cell lines known to express MT1-MMP and MMP-2. MMP-2 mRNA was expressed in 31 of 33 and MT1-MMP mRNA was expressed in 29 of 33 tumor cases. MMP-2 mRNA was predominantly expressed in desmoplastic fibroblasts and in the subepithelial stroma. MT1-MMP mRNA showed some colocalization with MMP-2 in stromal cells. Neoplastic epithelial cell labeling for MT1-MMP mRNA was present in borderline and malignant tumors but not in benign tumors, and was invariably less than stromal labeling. Xenografts of DOV 13, SKOV 3, and MCF 7 cells showed some stromal localization of MMP-2 mRNA and weak labeling of DOV 13 cells. There was variable labeling for MT1-MMP mRNA in the neoplastic cells only. The colocalization of MT1-MMP and MMP-2 mRNAs in ovarian carcinoma stroma supports the view that MT1-MMP is closely associated with MMP-2 expression and function. It suggests that either additional mechanisms are involved in regulating MMP-2 activation at the tumor cell surface, or more intriguingly, that desmoplastic fibroblasts may be the primary mediators of extracellular matrix remodeling with respect to this system.

Actins↗
PubMed1998

Differential expression of vascular endothelial growth factor mRNA vs protein isoform expression in human breast cancer and relationship to eIF-4E.

Angiogenesis is the formation of new blood vessels from the existing vasculature. Vascular endothelial growth factor (VEGF) is an endothelium-specific angiogenic factor strongly implicated in pathological angiogenesis. In this study, the mRNA and protein expression of the four alternatively spliced VEGF isoforms (121, 165, 189 and 206 amino acids) were examined in normal and malignant breast tissues. Three VEGF transcripts were detected in both (121>165>189), whereas only VEGF165 protein was detected. The tumours expressed more VEGF mRNA (P = 0.02) and protein (P < 0.0001), with eight-fold more VEGF protein generated per mRNA unit (P = 0.009). To examine this further, the expression of eIF-4E, a translation initiation factor, was examined. Increased eIF-4E mRNA levels were detected in the tumours (P < 0.0001) that correlated with VEGF mRNA (P = 0.0002), implying co-regulation of these genes. VEGF mRNA expression was elevated in tumours expressing the epidermal growth factor receptor (P < 0.01), but there was no difference according to oestrogen receptor status (P = 0.9), node status (P = 0.09) or between differing histologies (P = 0.4). These data suggest that elevated VEGF protein expression, by both enhanced transcription and translation, is a potential means by which tumour angiogenesis is induced in breast carcinomas. VEGF expression is also significantly associated with factors correlating with a poor outcome, implying a role in progression of this disease.

Adult↗
PubMed1998

Basal cell carcinoma development is associated with induction of the expression of the transcription factor Gli-1.

Recent work has established that activation of Hedgehog/patched signalling plays a key role in the development of basal cell carcinomas (BCCs). In Drosophila the effects of hedgehog signalling are mediated by the transcription factor Cubitus interruptus, which is homologous to the mammalian Gli family of transcription factors. In order to investigate the downstream consequences of patched gene inactivation in BCCs, we have investigated the expression of Gli-1 and Gli-3 in normal skin and BCCs by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. Gli-3 was found to be expressed in both normal skin and BCCs by both RT-PCR and in situ hybridization using a Gli-3-specific probe. Using a sensitive RT-PCR assay we were unable to detect Gli-1 transcripts in normal skin. Gli-1 was expressed in 13 of 14 BCCs examined, and in situ hybridization confirmed that the transcripts were localized to the epithelial component of the tumours. Our results demonstrate that inactivation of the patched gene BCCs is associated with the accumulation of Gli-1 transcripts. These findings suggest that the Gli-1 transcription factor plays a key role in BCC development.

Basal Cell Carcinoma↗
PubMed1998

Primary mucinous carcinomas of the skin express TFF1, TFF3, estrogen receptor, and progesterone receptors.

Mucinous carcinoma may present at various sites, including the breast and the gastrointestinal tract. Rarely, such tumors arise within the skin. Comparatively, breast lesions are relatively common and usually associated with a good prognosis. When pure, they are typically estrogen (ER) and progesterone receptor (PR) positive and responsive to tamoxifen. The authors studied 12 mucinous carcinomas of the skin and compared the morphology with that of typical mammary lesions. The authors also evaluated for expression of estrogen receptor, progesterone receptor, and the mucus-associated peptides of the trefoil factor family (TFF), TFF1 (formerly pS2) and TFF2 (formerly SP), using immunohistochemistry. The localization of mRNAs for TFF1, TFF2, and TFF3 (formally ITF) was also studied in a subset of three tumors, using in-situ hybridization with S35 labeled riboprobes. The Grimelius stain was used to look for evidence of neuroendocrine differentiation. Eight resembled type A mucinous carcinomas of the breast, two resembled type B, and one had composite features. The 12th was a papillary neoplasm. The two type B tumors exhibited argyrophilia. All showed strong nuclear staining with the estrogen receptor antibody but a more varied pattern with antibodies to progesterone receptor and TFF1. None labeled for TFF2. The detection of TFF1 in mammalian skin is a novel finding. Cutaneous mucinous carcinoma shows strong similarities to its mammary counterpart, including expression of estrogen receptor, TFF1, and TFF3 mRNA. These observations suggest that some mucinous carcinomas of the skin might respond to antiestrogenic therapies.

Adenocarcinoma, Mucinous↗