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W F Bodmer

Publications and source records attributed to W F Bodmer.

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

Mutated epithelial cadherin is associated with increased tumorigenicity and loss of adhesion and of responsiveness to the motogenic trefoil factor 2 in colon carcinoma cells.

Epithelial (E)-cadherin and its associated cytoplasmic proteins (alpha-, beta-, and gamma-catenins) are important mediators of epithelial cell-cell adhesion and intracellular signaling. Much evidence exists suggesting a tumor/invasion suppressor role for E-cadherin, and loss of expression, as well as mutations, has been described in a number of epithelial cancers. To investigate whether E-cadherin gene (CDH1) mutations occur in colorectal cancer, we screened 49 human colon carcinoma cell lines from 43 patients by single-strand conformation polymorphism (SSCP) analysis and direct sequencing. In addition to silent changes, polymorphisms, and intronic variants in a number of the cell lines, we detected frameshift single-base deletions in repeat regions of exon 3 (codons 120 and 126) causing premature truncations at codon 216 in four replication-error-positive (RER+) cell lines (LS174T, HCT116, GP2d, and GP5d) derived from 3 patients. In LS174T such a mutation inevitably contributes to its lack of E-cadherin protein expression and function. Transfection of full-length E-cadherin cDNA into LS174T cells enhanced intercellular adhesion, induced differentiation, retarded proliferation, inhibited tumorigenicity, and restored responsiveness to the migratory effects induced by the motogenic trefoil factor 2 (human spasmolytic polypeptide). These results indicate that, although inactivating E-cadherin mutations occur relatively infrequently in colorectal cancer cell lines overall (3/43 = 7%), they are more common in cells with an RER+ phenotype (3/10 = 30%) and may contribute to the dysfunction of the E-cadherin-catenin-mediated adhesion/signaling system commonly seen in these tumors. These results also indicate that normal E-cadherin-mediated cell adhesion can restore the ability of colonic tumor cells to respond to trefoil factor 2.

Animals↗
PubMed1999

Target genes of beta-catenin-T cell-factor/lymphoid-enhancer-factor signaling in human colorectal carcinomas.

Mutations in the adenomatous polyposis coli or beta-catenin gene lead to cytosolic accumulation of beta-catenin and, subsequently, to increased transcriptional activity of the beta-catenin-T cell-factor/lymphoid-enhancer-factor complex. This process seems to play an essential role in the development of most colorectal carcinomas. To identify genes activated by beta-catenin overexpression, we used colorectal cell lines for transfection with the beta-catenin gene and searched for genes differentially expressed in the transfectants. There are four genes affected by beta-catenin overexpression; three overexpressed genes code for two components of the AP-1 transcription complex, c-jun and fra-1, and for the urokinase-type plasminogen activator receptor (uPAR), whose transcription is activated by AP-1. The direct interaction of the beta-catenin-T cell-factor/lymphoid-enhancer-factor complex with the promoter region of c-jun and fra-1 was shown in a gel shift assay. The concomitant increase in beta-catenin expression and the amount of uPAR was confirmed in primary colon carcinomas and their liver metastases at both the mRNA and the protein levels. High expression of beta-catenin in transfectants, as well as in additionally analyzed colorectal cell lines, was associated with decreased expression of ZO-1, which is involved in epithelial polarization. Thus, accumulation of beta-catenin indirectly affects the expression of uPAR in vitro and in vivo. Together with the other alterations, beta-catenin accumulation may contribute to the development and progression of colon carcinoma both by dedifferentiation and through proteolytic activity.

Adenocarcinoma↗
PubMed1999

Somatic mutations of the first 14 exons of APC in hamartomatous polyps of the colon.

Although hamartomatous or hyperplastic polyps are rarely accompanied by adenomatous or carcinomatous foci, the role of APC (MIM# 175100) mutations in these polyps is not clear. The neoplastic potential of these polyps was assessed with regard to somatic mutation of the first 14 exons of APC. DNA from 14 hamartomatous polyps (12 patients with juvenile polyp, JP; two patients with Peutz-Jeghers syndrome, PJS) and 27 hyperplastic polyps was used. Exons 1-14 of APC were amplified using verified oligonucleotide primers, and PCR-SSCP analysis was performed. Translation-terminating mutation in exon 15 was also screened using the protein truncation test. All mutations found were transitions or transversions with heterozygous alleles of both wild-type and mutant APC in exons 2, 9, 10, and 11. Four hamartomatous polyps (three from JP and one from PJS) showed seven, new mutations and one common APC variant (codon 486), whereas no hyperplastic polyps demonstrated mutation. APC mutation was not correlated with previous history of colorectal carcinoma or number of polyps. Since all mutations were missense or silent mutations occurred in exons not previously known to have functionally relevant area, their phenotypic implication appeared to be limited.

Colonic Polyps↗
PubMed1999

Distribution of carcinoembryonic antigen and biologic behavior in colorectal carcinoma.

PURPOSE: Carcinoembryonic antigen is assumed from the results of several experiments to be associated with invasion of colorectal carcinoma by adhesion or contact inhibition. The patterns and the intensity of carcinoembryonic antigen distribution in colorectal carcinoma were assessed to verify whether they were correlated with malignant potential from those biologic characteristics. METHODS: Carcinoembryonic antigen distribution was tested in the archival samples of 149 colorectal carcinomas by immunohistochemistry, using three characterized anti-carcinoembryonic antigen monoclonal antibodies: T84.66, PR1A3, and PR3B10. The distribution patterns in neoplastic tissue were categorized into unstained, apicoluminal, and diffuse cytoplasmic patterns. Tumor, invasive tumor margin, and tissue surrounding the tumor were examined. RESULTS: Although all three antibodies revealed a positive correlation, T84.66 showed better discrimination than the others. Although none of the negative staining of the tumor or invasive tumor margin showed recurrence, the apicoluminal pattern showed recurrence, and the diffuse pattern showed the most frequent recurrence (P < 0.01). Recurrence was also associated with staining intensity in the apicoluminal pattern in both the tumor and invasive tumor margin (P < 0.05). Infiltrative tumor growth and lymph node metastasis were more frequent in cases of positive staining in tissue surrounding the tumor. Patients with the apicoluminal pattern achieved longer survival than patients with the diffuse-cytoplasmic pattern in the invasive tumor margin (P = 0.024) by a multivariate analysis including tumor stage and histologic differentiation. CONCLUSION: The distribution of carcinoembryonic antigen in tumors and surrounding tissue seems to be closely correlated with invasiveness and metastatic behavior in colorectal carcinoma. Carcinoembryonic antigen immune staining can be considered as an efficient tool to determine groups with risk of recurrence.

Adenocarcinoma↗
PubMed1999

Genetic pathways in colorectal and other cancers.

Cells from cancers show aberrant behaviour such as unrestrained growth, invasion into adjacent tissue and metastasis. All these features of cancer cell behaviour can be explained in terms of genetic changes and the functional impact of these changes. In this review, colorectal cancer (CRC) is examined as a classical example of multistep carcinogenesis. First there is an overview which shows that cancers develop by a process of somatic evolution. This gives rise to preferred genetic pathways of tumorigenesis. The factors which may influence the development and ultimate choice of genetic pathways are then examined. Next, CRC is studied as a specific disease and the putative genetic pathways are described. The mutations that comprise these pathways and the possible functional sequelae of these are explored. The review concludes with a look at those avenues which may further elucidate the natural history of CRC and lead to improved therapy.

Colorectal Neoplasms↗
PubMed1999

Genetic pathways in colorectal and other cancers.

Cells from cancers show aberrant behaviour such as unrestrained growth, invasion into adjacent tissue and metastasis. All these features of cancer cell behaviour can be explained in terms of genetic changes and the functional impact of these changes. In this review, colorectal cancer (CRC) is examined as a classical example of multistep carcinogenesis. First there is an overview which shows that cancers develop by a process of somatic evolution. This gives rise to preferred genetic pathways of tumorigenesis. The factors which may influence the development and ultimate choice of genetic pathways are then examined. Next, CRC is studied as a specific disease and the putative genetic pathways are described. The mutations that comprise these pathways and the possible functional sequelae of these are explored. The review concludes with a look at those avenues which may further elucidate the natural history of CRC and lead to improved therapy.

Cell Transformation, Neoplastic↗
PubMed1999

High-throughput class I HLA genotyping using fluorescence resonance energy transfer (FRET) probes and sequence-specific primer-polymerase chain reaction (SSP-PCR).

We have developed a semi-automated HLA class I typing system utilising TET/TAMRA-labelled fluorescence resonance energy transfer (FRET) hydrolysis probes. The results from 87 individuals are in full concordance with serology and conventional gel-based systems. This assay replaces labour-intensive conventional gel-based DNA typing and has a higher allelic resolution than serology. Our approach differs from previously published fluorogenic probe typing protocols in that it provides simultaneous typing of HLA-A, -B and -C loci to medium resolution. Furthermore, by using equipment that is not specific to FRET probe analysis our system has in-built expansion capacity to 384 reactions per plate, thus making it applicable to high-throughput population screening. Automation is achieved through the use of computer software which analyses direct input from the fluorescence reader, allowing high throughput with a low inherent error rate.

DNA Primers↗
PubMed1999

Microsatellite instability in benign skin lesions in hereditary non-polyposis colorectal cancer syndrome.

The coexistence of cutaneous and extra-cutaneous malignancies within one family could be explained by shared genetic mechanisms such as common tumor suppressor gene mutations or oncogene activation, as well as mutations in DNA repair genes. Hereditary non-polyposis colorectal cancer syndrome (HNPCC) and its variant Muir-Torre syndrome (MTS) are caused by germline DNA mismatch repair gene mutations. Colonic and endometrial tumors from HNPCC patients exhibit microsatellite instability (MSI), as do sebaceous lesions in MTS. We recruited individuals from cancer prone families to determine if MSI is found in benign and malignant skin lesions and to assess whether MSI in the skin is predictive of genomic instability with susceptibility to tumors characteristic of HNPCC. One hundred and fifteen benign, dysplastic, and malignant skin lesions from 39 cancer prone families were analyzed. Thirteen benign skin lesions from three individuals belonging to two HNPCC pedigrees showed MSI. No mutations in hMSH2 and hMLH1 were found in two of the three individuals with RER + skin lesions. We found MSI in non-sebaceous non-dysplastic skin lesions in HNPCC pedigrees. MSI was not found in skin lesions within other family cancer syndromes. These results have important clinical implications as the detection of MSI in prevalent readily accessible skin lesions could form the basis of noninvasive screening for HNPCC families. It may also be a valuable tool in the search for new mismatch repair genes.

Adenoma↗
PubMed1999

1998 Runme Shaw Memorial Lecture: somatic evolution of cancer.

The interpretation of cancer as a somatic evolutionary process involving genetic mutation followed by selection, traces its origins to the early years this century. The dramatic developments in molecular genetics have substantiated these early ideas. Through the application of positional cloning and genomic analysis, many mutations in particular genes, both dominant oncogenes and tumour suppressor genes have now been found in a wide variety of tumours. Other genetic events such as non-disjunction leading to haploid expression of a gene and so reduced gene dosage, or epigenetic changes following, for example, changes in methylation patterns leading to reduced or increased gene expression, may also play critical roles in the progression of a cancer. The analysis of mutations at different stages of colorectal cancer provides a good model for following the initiation and progression of a cancer. Mutations in the APC gene, which explain familial adenomatous polyposis, occur in a high proportion of sporadic colorectal carcinomas and appear to be the earliest known changes. Patterns of mutation in the gene suggest dominant negative or gain of function effects, and also reveal important low penetrance subpolymorphic missense mutations that nevertheless may have a very significant impact on the genetic contribution to colorectal cancer susceptibility. Mutations are also found in related genes in the APC pathway, such as beta-catenin and E-cadherin. Mutations in mismatch repair genes (hMLH1 and hMSH2) have also been shown to occur, as well as reduced expression due to methylation changes, in 10% to 20% of sporadic colorectal carcinomas. In addition, mutations in the well known oncogenes p53 and ras are commonly found. The growth of a cancer is a balance between the rate of cell division and the rate of cell death or apoptosis. Thus, genetic changes which reduce the probability of apoptosis, such as p53 and probably hMLH1, are as important a feature of the evolution of a cancer as those which enhance the independence (APC) and rate of cell division (growth factors). Simple models for the evolution of a cancer that take into account these two processes, show that cancers evolve initially by a series of finite increases in cell population size, following which there may be long periods of cell turnover during which there is an opportunity for further mutation and selection. This explains the long lag periods between the initiation and subsequent progression of most cancers. Our rapidly developing understanding of cancers at the fundamental genetic level provides new opportunities for developing targeted treatments, as well as novel approaches to prevention and early detection.

Adenomatous Polyposis Coli↗
PubMed1998

The APC variants I1307K and E1317Q are associated with colorectal tumors, but not always with a family history.

Classical familial adenomatous polyposis (FAP) is a high-penetrance autosomal dominant disease that predisposes to hundreds or thousands of colorectal adenomas and carcinoma and that results from truncating mutations in the APC gene. A variant of FAP is attenuated adenomatous polyposis coli, which results from germ-line mutations in the 5' and 3' regions of the APC gene. Attenuated adenomatous polyposis coli patients have "multiple" colorectal adenomas (typically fewer than 100) without the florid phenotype of classical FAP. Another group of patients with multiple adenomas has no mutations in the APC gene, and their phenotype probably results from variation at a locus, or loci, elsewhere in the genome. Recently, however, a missense variant of APC (I1307K) was described that confers an increased risk of colorectal tumors, including multiple adenomas, in Ashkenazim. We have studied a set of 164 patients with multiple colorectal adenomas and/or carcinoma and analyzed codons 1263-1377 (exon 15G) of the APC gene for germ-line variants. Three patients with the I1307K allele were detected, each of Ashkenazi descent. Four patients had a germ-line E1317Q missense variant of APC that was not present in controls; one of these individuals had an unusually large number of metaplastic polyps of the colorectum. There is increasing evidence that there exist germ-line variants of the APC gene that predispose to the development of multiple colorectal adenomas and carcinoma, but without the florid phenotype of classical FAP, and possibly with importance for colorectal cancer risk in the general population.

Adult↗
PubMed1998

Intestinal trefoil factor controls the expression of the adenomatous polyposis coli-catenin and the E-cadherin-catenin complexes in human colon carcinoma cells.

Intestinal trefoil factor 3 (TFF3) is a member of the trefoil family of peptides, small molecules constitutively expressed in epithelial tissues, including the gastrointestinal tract. TFF3 has been shown to promote migration of intestinal epithelial cells in vitro and to enhance mucosal healing and epithelial restitution in vivo. In this study, we evaluated the effect of recombinant TFF3 (rTFF3) stimulation on the expression and cellular localization of the epithelial (E)-cadherin-catenin complex, a prime mediator of Ca2+ dependent cell-cell adhesion, and the adenomatous polyposis coli (APC)-catenin complex in HT29, HCT116, and SW480 colorectal carcinoma cell lines. Stimulation by rTFF3 (10(-9) M and 10(-8) M) for 20-24 hr led to cell detachment and to a reduction in intercellular adhesion in HT29 and HCT116 cells. In both cell lines, E-cadherin expression was down-regulated. The expression of APC, alpha-catenin and beta-catenin also was decreased in HT29 cells, with a translocation of APC into the nucleus. No change in either cell adhesion or in the expression of E-cadherin, the catenins, and APC was detected in SW480 cells. In addition, TFF3 induced DNA fragmentation and morphological changes characteristic of apoptosis in HT29. Tyrphostin, a competitive inhibitor of protein tyrosine kinases, inhibited the effects of TFF3. Our results indicate that by perturbing the complexes between E-cadherin, beta-catenin, and associated proteins, TFF3 may modulate epithelial cell adhesion, migration, and survival.

Adenomatous Polyposis Coli Protein↗
PubMed1998

APC in the regulation of intestinal crypt fission.

The functional effects of APC (adenomatous polyposis coli gene) germ-line mutations on crypt fission and cell proliferation were investigated in the normal intestine of human familial adenomatous polyposis (FAP) and multiple intestinal neoplasia (MIN) mice. Compared with controls, there was a 19-fold increase in the proportion of crypts in fission in FAP colon [95 per cent confidence interval (CI): 11-32, P < 0.0001], and a 75 and 61 per cent increase in MIN colon (95 per cent CI: 1.08-2.82, P < 0.02) and small bowel, respectively (95 per cent CI: 1.31-1.99, P < 0.001). In marked contrast, no significant differences in intra-cryptal epithelial cell proliferation or mitotic distribution were seen. Furthermore, 10.9 per cent of crypts in FAP were in asymmetrical fission as opposed to only 1 per cent in controls (P = 0.001). The largest relative increases in MIN crypt fission were in the colon (proximal and distal colon:190 per cent, P = 0.02 and 83 per cent, P = 0.01), suggesting that Apc mutations exert their maximal influence site-specifically. However, sites with the highest relative increases were also those with the largest eventual tumour sizes, but not the highest polyp counts. Three-dimensional serial section reconstruction analysis corroborated that FAP adenomas enlarge by crypt fission, which was frequently both asymmetrical and atypical. It is proposed that the absence of an increase in intestinal cell division infers that APC regulates intestinal crypt differentiation, specifically through the crypt cycle. This role appears analogous to the control of axis re-duplication in embryonic development, when downstream targets of APC are over-expressed. It is concluded that in vivo, the major defect in pre-neoplastic intestine harbouring APC mutations is elevated rates of crypt fission, and that this is also the mode by which micro-adenomas enlarge.

Adenoma↗
PubMed1998

Defects in mismatch repair occur after APC mutations in the pathogenesis of sporadic colorectal tumours.

The roles of the intrinsic mutation rate and genomic instability in tumorigenesis are currently controversial. In most colorectal tumours, it is generally supposed that the first mutations occur at the adenomatous polyposis coli (APC) locus; APC mutations are thought to provide cells with a selective advantage but have no known effect on the mutation rate. It has also been suggested that genomic instability is the initiating event in colorectal tumorigenesis and, if this is true, mutations of DNA mismatch repair (MMR) genes (or at similar loci) are the most likely candidates. If defective MMR precedes APC mutations, the APC mutations of colon tumours with defective MMR and hence replication errors (RER+) should differ from those of RER- tumours, in at least three specific ways: (1) a higher frequency of allele loss at APC in RER- tumours; (2) more frameshift than nonsense mutations in RER+ tumours; and (3) APC mutations in simple repeat sequences [(N)n, (N1N2)n, or (N1N2N3)n] in RER+ tumours. We found no evidence that sporadic RER+ and RER- colon cancers (including cell lines) differ in any of these three ways. Although it remains possible that MMR is abnormal in tumours from HNPCC families before APC mutations occur, it is likely that in sporadic colon tumours, APC mutations, rather than genomic instability, are the initiating events in tumorigenesis.

Alleles↗
PubMed1998

Loss of Bcl-2 expression correlates with tumour recurrence in colorectal cancer.

AIMS: To investigate the association between immunohistochemical expression of Bcl-2 and p53 in colorectal cancer and tumour recurrence following surgery. METHODS: Sixty six cases of Dukes' B colorectal carcinoma were studied. All tumours were moderately differentiated and were shown to be histologically clear of the resection margins. Immunohistochemistry was performed on formalin fixed paraffin wax embedded tissue using monoclonal antibodies for p53 and Bcl-2. The Bcl-2 staining was assessed separately for relative intensity of staining and percentage of positive tumour cells and given a final score which combined the two factors. The p53 staining was assessed on number of positive tumour cells only. The patterns of immunostaining of those cases in which there had been tumour recurrence were compared with those cases in which there was no tumour recurrence (controls). RESULTS: A statistically significant inverse association was found between Bcl-2 score and tumour recurrence (median Bcl-2 score of 6 (interquartile range (IQR) 2-9) in patients with recurrent disease; median Bcl-2 score of 8 (IQR 6-10) in those without recurrence; p = 0.03). When examined separately, both the intensity of expression and percentage of positive tumour cells were significantly associated with tumour recurrence (p = 0.04 in each case). There was no association between p53 staining and tumour recurrence. CONCLUSION: Results suggest that, when controlled for differentiation, Bcl-2 expression is a prognostic marker and may be useful as an adjunctive test in clinical decision making.

Biomarkers, Tumor↗
PubMed1997

Genomic and cDNA sequence analysis of the cell matrix adhesion regulator gene.

The cell matrix adhesion regulator (CMAR) gene has been suggested to be a signal transduction molecule influencing cell adhesion to collagen and, through this, possibly involved in tumor suppression. The originally reported CMAR cDNA was 464 bp long with a tyrosine phosphorylation site at the extreme 3' end, which mutagenesis studies had shown to be central to the function of this gene. Since the discovery of a 4-bp insertion polymorphism within the originally reported coding region, further sequence information has been obtained. The cDNA has been extended 5' by approximately 2 kb revealing a 559-bp region showing strong homology to the proposed 5' untranslated sequence of a murine protein kinase receptor family member, variant in kinase (vik). CMAR genomic sequencing has shown the presence of an intron, the intron/exon boundary lying within this region of homology. An RNA transcript for CMAR of approximately 2.5 kb has also been identified. The data suggest complex mechanisms for control of expression of two closely associated genes, CMAR and the vik- associated sequence.

ATPases Associated with Diverse Cellular Activitie↗