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Edward Gabrielson

Publications and source records attributed to Edward Gabrielson.

31 records · Page 2Linked to original sources
PubMed2003

A neural survival factor is a candidate oncogene in breast cancer.

Using serial analysis of gene expression (SAGE), we identified a SAGE tag that was present only in invasive breast carcinomas and their lymph node metastases. The transcript corresponding to this SAGE tag, dermcidin (DCD), encodes a secreted protein normally expressed only in the pons of the brain and sweat glands. Array comparative genomic hybridization, fluorescence in situ hybridization, and immunohistochemical analyses determined that DCD is overexpressed in approximately 10% of invasive breast carcinomas; in some cases its overexpression is coupled with a focal copy number gain of its locus at 12q13.1, and its expression is associated with advanced clinical stage and poor prognosis. Expression of DCD in breast cancer cells promotes cell growth and survival and reduces serum dependency. Putative high- and low-affinity receptors for DCD are present on the cell surface of breast carcinomas and neurons of the brain. Based on these data we hypothesize that DCD may play a role in tumorigenesis by means of enhancing cell growth and survival in a subset of breast carcinomas.

Amino Acid Sequence↗
PubMed2003

WNT7a induces E-cadherin in lung cancer cells.

E-cadherin loss in cancer is associated with de-differentiation, invasion, and metastasis. Drosophila DE-cadherin is regulated by Wnt/beta-catenin signaling, although this has not been demonstrated in mammalian cells. We previously reported that expression of WNT7a, encoded on 3p25, was frequently downregulated in lung cancer, and that loss of E-cadherin or beta-catenin was a poor prognostic feature. Here we show that WNT7a both activates E-cadherin expression via a beta-catenin specific mechanism in lung cancer cells and is involved in a positive feedback loop. Li+, a GSK3 beta inhibitor, led to E-cadherin induction in an inositol-independent manner. Similarly, exposure to mWNT7a specifically induced free beta-catenin and E-cadherin. Among known transcriptional suppressors of E-cadherin, ZEB1 was uniquely correlated with E-cadherin loss in lung cancer cell lines, and its inhibition by RNA interference resulted in E-cadherin induction. Pharmacologic reversal of E-cadherin and WNT7a losses was achieved with Li+, histone deacetylase inhibition, or in some cases only with combined inhibitors. Our findings provide support that E-cadherin induction by WNT/beta-catenin signaling is an evolutionarily conserved pathway operative in lung cancer cells, and that loss of WNT7a expression may be important in lung cancer development or progression by its effects on E-cadherin.

Cadherins↗
PubMed2003

Dykellic acid inhibits phorbol myristate acetate-induced matrix metalloproteinase-9 expression by inhibiting nuclear factor kappa B transcriptional activity.

Proteolytic degradation of the extracellular matrix and tumor metastasis correlate with expression of endopeptidases known as matrix metalloproteinases (MMPs). Expression of MMPs is regulated by cytokines and signal transduction pathways, including those activated by phorbol myristate acetate. We found that dykellic acid, a fungal metabolite, significantly inhibits the phorbol myristate acetate-induced increase in MMP-9 expression and activity. These effects of dykellic acid are time- and dose-dependent, and correlate with decreased MMP-9 promoter activity and mRNA expression. Whereas this compound does not affect DNA binding activity of nuclear factor kappa B (NF kappa B), dykellic acid does inhibit transactivation of NF kappa B. These data demonstrate a role for NF kappa B in the regulation of MMP-9 expression and the ability of dykellic acid to suppress this action of NF kappa B.

Enzyme Induction↗
PubMed2003

Molecular markers in ductal carcinoma in situ of the breast.

Gene expression patterns in ductal carcinoma in situ (DCIS), and in invasive, and metastatic breast tumors were determined using serial analysis of gene expression (SAGE). We used mRNA in situ hybridization to examine gene expression at the cellular level and immunohistochemistry on tissue microarrays to determine association between gene expression patterns and histopathologic characteristics of the tumors. We found that that the most dramatic transcriptome change occurs at the normal to DCIS transition, while there is no clear universal "in situ" or "invasive" tumor molecular signature. From the 16,430 transcripts analyzed, we identified only 5 and 11 that were preferentially up-regulated in DCIS and invasive tumors, respectively. The majority of invasive cancer specific SAGE tags correspond to novel genes. The genes we identified may define biologically and clinically meaningful subgroups of DCIS with a high risk of progression to invasive disease.

Breast Neoplasms↗
PubMed2002

Nuclear genes involved in mitochondria-to-nucleus communication in breast cancer cells.

BACKGROUND: The interaction of nuclear and mitochondrial genes is an essential feature in maintenance of normal cellular function. Of 82 structural subunits that make up the oxidative phosphorylation system in the mitochondria, mitochondrial DNA (mtDNA) encodes 13 subunits and rest of the subunits are encoded by nuclear DNA. Mutations in mitochondrial genes encoding the 13 subunits have been reported in a variety of cancers. However, little is known about the nuclear response to impairment of mitochondrial function in human cells. RESULTS: We isolated a Rho0 (devoid of mtDNA) derivative of a breast cancer cell line. Our study suggests that depletion of mtDNA results in oxidative stress, causing increased lipid peroxidation in breast cancer cells. Using a cDNA microarray we compared differences in the nuclear gene expression profile between a breast cancer cell line (parental Rho+) and its Rho0 derivative impaired in mitochondrial function. Expression of several nuclear genes involved in cell signaling, cell architecture, energy metabolism, cell growth, apoptosis including general transcription factor TFIIH, v-maf, AML1, was induced in Rho0 cells. Expression of several genes was also down regulated. These include phospholipase C, agouti related protein, PKC gamma, protein tyrosine phosphatase C, phosphodiestarase 1A (cell signaling), PIBF1, cytochrome p450, (metabolism) and cyclin dependent kinase inhibitor p19, and GAP43 (cell growth and differentiation). CONCLUSIONS: Mitochondrial impairment in breast cancer cells results in altered expression of nuclear genes involved in signaling, cellular architecture, metabolism, cell growth and differentiation, and apoptosis. These genes may mediate the cross talk between mitochondria and the nucleus.

Breast Neoplasms↗
PubMed2002

Staurosporine-induced G(1) arrest in cancer cells depends on an intact pRB but is independent of p16 status.

Staurosporine and its derivative 7-hydroxystaurosporine are protein kinase inhibitors that are being considered for treatments of cancers. Several recent studies have shown that cells with defective pRB protein are resistant to the G(1) cell cycle-inhibiting effects of staurosporine compounds. In this study, we examined the effect of staurosporine on two breast cancer-derived and three lung cancer-derived cell lines characterized by deficiencies in the p16 tumor suppressor. All of these p16-deficient cell lines are highly sensitive to staurosporine-induced inhibition of pRB phosphorylation and induction of arrest in G(1). This response is similar to that seen in cultured normal human bronchial epithelial cells and normal mammary epithelial cells, but strikingly different than the staurosporine resistance seen in cancer cells with defective pRB. Interestingly, inhibition of pRB phosphorylation could be seen within 4 h of treatment, suggesting that this inhibition is a consequence of direct effects of staurosporine on protein kinase(s) rather than a result of induction of other cyclin-dependent kinase inhibitors. Our findings suggest that different types of cancer cells have vastly different responses to the staurosporine class of agents, and that evaluation of pRB and p16 will help predict the response of the cancer cells to these agents.

Adenocarcinoma↗
PubMed2002

Molecular cloning and characterization of the human budding uninhibited by benomyl (BUB3) promoter.

Recently, cDNA corresponding to the human homologue of the BUB3 (budding uninhibited by benomyl) mitotic checkpoint protein has been identified and cloned. Previous studies from our laboratory and others have found this gene to localize to 10q26, a region that is frequently altered in various human cancers. We describe here a series of studies designed to understand the genomic structure of BUB3, particularly as it relates to regulation of gene expression. The human BUB3 gene has seven exons and six introns, and spans a genomic region of over 16 kb. The four WD repeat sequences in this gene are localized to exons 2, 4, and 6, and there is a major transcriptional start site located 554 nucleotides upstream of the ATG translation initiator codon. The promoter region lacks a TATA box but contains potential binding sites for the transcriptional factors including SP1, E2F, c-Myc, C/EBP and NFkappaB. To analyse the regulatory mechanisms controlling hBUB3 gene expression, we characterized the 5'-flanking region from nucleotide -1.3 to +0.58 kb by cloning various potions of this region in front of a luciferase reporter sequence. These experiments indicate that this region 5' region contains distinctive positive and negative regulatory elements.

5' Flanking Region↗
PubMed2002

Combined use of oligonucleotide and tissue microarrays identifies cancer/testis antigens as biomarkers in lung carcinoma.

High density oligonucleotide microarrays (OMAs) have been used recently to profile gene expression in lung carcinoma tissue homogenates. The length of the lists of potentially interesting genes generated by these studies is daunting, and biological and clinical relevance of these lists remains to be validated. Moreover, specific identification of individual biomarkers that might be used for early detection and surveillance has not been the objective of these early studies. We have developed a schema for combining the data derived from the OMA analysis of a few lung cancer cell lines with immunohistochemical testing of tissue microarrays to rapidly identify biomarkers of potential clinical relevance. Initially, we profiled gene expression in lung tumor cell lines using the Affymetrix HG-U95Av2 OMA. RNA from 2 non-small cell lung cancer (NSCLC) cell lines (A549 and H647) and 2 small cell lung cancer (SCLC) cell lines (SHP-77 and UMC-19) were tested. Cells from 1 histologically and cytogenetically normal bronchial epithelial primary culture from a volunteer who had never smoked and 10 samples of histologically unremarkable lung tissue from resection specimens served as normalization controls. Array results were analyzed with Gene Spring software. Results were confirmed by reverse transcription-PCR in an expanded number of cell lines. We then validated the cell line data by immunohistochemical testing for protein using a tissue microarray containing 187 NSCLC clinical samples. Of the 20 most highly expressed genes in the tumor lines, 6 were members of the cancer/testis antigen (CTAG) gene group including 5 MAGE-A subfamily members and NY-ESO-1. SCLC lines strongly expressed all of the MAGE-A genes as well as NY-ESO-1, whereas NSCLC lines expressed a subset of MAGE-A genes at a lower level of intensity and failed to express NY-ESO-1. Reverse transcription-PCR of an extended series of 25 lung cancer cell lines including 13 SCLC, 9 NSCLC, and 3 mesothelioma lines indicated that MAGE-A10 and NY-ESO-1 were expressed only by SCLC, and that MAGE-A1, 3, 6, 12, and 4b were expressed by both SCLC and NSCLC. By immunohistochemistry using the monoclonal antibody 6C1 that recognizes several MAGE-A gene subfamily members, 44% of NSCLC clearly expressed MAGE-A proteins in cytoplasm and/or nucleus. Expression of MAGE-A genes did not correlate with survival but did correlate with histological classification with squamous carcinomas more frequently MAGE-A positive than other NSCLC types (P < 0.00002). We conclude that expression of CTAG gene products, whereas apparently not of prognostic importance, may be useful for early detection and surveillance because of a high level of specificity for central airway squamous and small cell carcinomas.

Antigens, Neoplasm↗
PubMed2002

A genomic screen for genes upregulated by demethylation and histone deacetylase inhibition in human colorectal cancer.

Aberrant hypermethylation of gene promoters is a major mechanism associated with inactivation of tumor-suppressor genes in cancer. We previously showed this transcriptional silencing to be mediated by both methylation and histone deacetylase activity, with methylation being dominant. Here, we have used cDNA microarray analysis to screen for genes that are epigenetically silenced in human colorectal cancer. By screening over 10,000 genes, we show that our approach can identify a substantial number of genes with promoter hypermethylation in a given cancer; these are distinct from genes with unmethylated promoters, for which increased expression is produced by histone deacetylase inhibition alone. Many of the hypermethylated genes we identified have high potential for roles in tumorigenesis by virtue of their predicted function and chromosome position. We also identified a group of genes that are preferentially hypermethylated in colorectal cancer and gastric cancer. One of these genes, SFRP1, belongs to a gene family; we show that hypermethylation of four genes in this family occurs very frequently in colorectal cancer, providing for (i) a unique potential mechanism for loss of tumor-suppressor gene function and (ii) construction of a molecular marker panel that could detect virtually all colorectal cancer.

Colorectal Neoplasms↗
PubMed2002

Assessment of mortality in patients enrolled in a risedronate clinical trial program: a retrospective cohort study.

Risedronate, a pyridinyl bisphosphonate, has been shown in large clinical trials to be effective in the prevention and treatment of osteoporosis. Analysis of safety data from these trials has shown that risedronate (2.5- and 5-mg doses) has an overall safety profile comparable to placebo during the course of the clinical trials. The clinical trials were powered appropriately to analyze the efficacy endpoints; however, patients were not systematically followed after completion of the clinical trials and therefore vital status for most of the patient cohort after the cessation of the clinical trials was unknown. In order to investigate further the safety profile of risedronate observed in the clinical trials database, we conducted a retrospective cohort mortality study among 7981 patients comprising the intent-to-treat population in three North American risedronate osteoporosis trials. No difference in all cause mortality was observed in patients receiving risedronate treatment compared with patients receiving placebo. There were also no differences between these groups in mortality due to all cancers, lung cancer, and gastrointestinal tract cancer. A trend toward lower cardiovascular mortality was observed in the risedronate groups compared with placebo; this difference was largely due to a significant reduction in stroke mortality in the active treatment groups. Follow-up mortality data in this retrospective cohort study demonstrate that treatment with risedronate has no effect on overall mortality rates.

Adult↗
PubMed2002

Variable levels of chromosomal instability and mitotic spindle checkpoint defects in breast cancer.

Cytogenetic analyses have revealed that many aneuploid breast cancers have cell-to-cell variations of chromosome copy numbers, suggesting that these neoplasms have instability of chromosome numbers. To directly test for possible chromosomal instability in this disease, we used fluorescent in situ hybridization to monitor copy numbers of multiple chromosomes in cultures of replicating breast cancer-derived cell lines and nonmalignant breast epithelial cells. While most (7 of 9) breast cancer cell lines tested are highly unstable with regard to chromosome copy numbers, others (2 of 9 cell lines) have a moderate level of instability that is higher than the "background" level of normal mammary epithelial cells and MCF-10A cells, but significantly less than that seen in the highly unstable breast cancer cell lines. To evaluate the potential role of a defective mitotic spindle checkpoint as a cause of this chromosomal instability, we used flow cytometry to monitor the response of cells to nocodazole-induced mitotic spindle damage. All cell lines with high levels of chromosomal instability have defective mitotic spindle checkpoints, whereas the cell lines with moderate levels of chromosomal instability (and the stable normal mammary cells and MCF10A cells) arrest in G(2) when challenged with nocodazole. Notably, the extent of mitotic spindle checkpoint deficiency and chromosome numerical instability in these cells is unrelated to the presence or absence of p53 mutations. Our results provide direct evidence for chromosomal instability in breast cancer and show that this instability occurs at variable levels among cells from different cancers, perhaps reflecting different functional classes of chromosomal instability. High levels of chromosomal instability are likely related to defective mitotic checkpoints but not to p53 mutations.

Breast Neoplasms↗
PubMed2002

Mucinous cancers have fewer genomic alterations than more common classes of breast cancer.

Mucinous cancers of the breast are distinguished histologically by their abundant pools of mucin and low degree of nuclear pleomorphism. Relative to the more common breast cancers of no distinctive type (ductal carcinoma), mucinous cancers have a relatively favorable prognosis. In a study of chromosomal changes in mucinous cancers, we evaluated the extent of loss of heterozygosity (LOH) at chromosomal regions commonly deleted in usual infiltrating ductal carcinoma, including markers on chromosomal arms 1p, 1q, 3p, 6q, 8p, 9p, 11p, 11q, 13q, 16q, 17p, and 17q. Remarkably, we found an average frequency of LOH of only 1.9 of these 12 chromosomal arms in 18 cases of mucinous carcinoma, compared to an average frequency of LOH of 6.4 of these same chromosomal arms in cases of infiltrating ductal cancer. In three of the 18 cases of mucinous carcinoma studied, including one case with regional lymph node metastases, no LOH was seen at any of the 12 chromosomal regions studied. We considered the possibility of other chromosomal loci being more commonly affected in mucinous cancers and conducted comparative genomic hybridization on six of the cases. These studies demonstrated a low overall frequency of genomic copy number changes (mean of 3.1 changes per case) and failed to reveal any other chromosomal locus with frequent losses that had not been evaluated by microsatellite analysis. Together, these data indicate that mucinous cancers of the breast do not have the extensive genomic alterations that are typically found in more common variants of breast cancer. Thus, mucinous cancers most likely have less genetic instability than most other forms of breast cancer and the molecular pathogenesis of this form of breast cancer is likely to be substantially different than that of usual ductal breast cancer.

Adenocarcinoma, Mucinous↗