Gynecologic surgeries and risk of ovarian cancer in women with BRCA1 and BRCA2 Ashkenazi founder mutations: an Israeli population-based case-control study.

Background: In the general population, the risk of developing ovarian cancer is reduced in women who have undergone tubal ligation, hysterectomy, or oophorectomy, although peritoneal cancer can arise after bilateral oophorectomy. In studies from genetic screening clinics, women with mutations in the breast and ovarian susceptibility genes BRCA1 and BRCA2 have been found to have a low risk of peritoneal carcinoma in the first years after bilateral oophorectomy. We assessed the level and persistence of reduction of ovarian (including peritoneal) cancer risk after gynecologic surgeries for women who carry BRCA1/2 mutations but were not selected from high-risk clinics.

CDKN2A point mutations D153spl(c.457G>T) and IVS2+1G>T result in aberrant splice products affecting both p16INK4a and p14ARF.

The CDKN2A gene, which encodes the proteins p16(INK4a) and p14(ARF), is located on chromosome 9p21. Germline mutations at this locus increase susceptibility to cutaneous malignant melanoma (CMM). In general, missense and nonsense mutations are primarily responsible for defective p16(INK4a) and possibly p14(ARF) protein function and account for approximately 20% of inherited CMM cases.

Elevated sod2 activity augments matrix metalloproteinase expression: evidence for the involvement of endogenous hydrogen peroxide in regulating metastasis.

Purpose: Elevated manganese superoxide dismutase (Sod2) levels have been reported to be associated with an increased frequency of tumor invasion and metastasis in certain cancers, and the aim of this study is to examine the molecular mechanisms by which this occurs.

Experimental Design: Sod2 and catalase overexpressing HT-1080 fibrosarcoma cell lines were used to evaluate the H(2)O(2)-dependent regulation of matrix metalloproteinase (MMP)-1 promoter activity, mitogen-activated protein (MAP) kinase signaling, DNA-binding activity, and MMP mRNA levels. The invasive and metastatic potential of Sod2 overexpressing cells was characterized using subrenal capsular implantation or tail vein injection of tumor cells into nude mice, respectively.

NPAS2: a gas-responsive transcription factor.

Neuronal PAS domain protein 2 (NPAS2) is a mammalian transcription factor that binds DNA as an obligate dimeric partner of BMAL1 and is implicated in the regulation of circadian rhythm. Here we show that both PAS domains of NPAS2 bind heme as a prosthetic group and that the heme status controls DNA binding in vitro. NPAS2-BMAL1 heterodimers, existing in either the apo (heme-free) or holo (heme-loaded) state, bound DNA avidly under favorably reducing ratios of the reduced and oxidized forms of nicotinamide adenine dinucleotide phosphate.

Two approaches to mutation detection based on functional data.

A new technique, denaturing high-performance liquid chromatography (dHPLC), allows for detection of any heterozygous sequence variation in a gene without prior knowledge of the precise location of the sequence change. The results of a dHPLC analysis are recorded in real-time in the form of a chromatogram that is sequence-specific. In this paper we present methods to classify an individual, based on the observed chromatogram, as a homozygous wild-type or a carrier of a specific variant for the given DNA segment by comparison to representative chromatograms that are obtained from the training set of individuals with known variant status.

Structure and interactions of PAS kinase N-terminal PAS domain: model for intramolecular kinase regulation.

PAS domains are sensory modules in signal-transducing proteins that control responses to various environmental stimuli. To examine how those domains can regulate a eukaryotic kinase, we have studied the structure and binding interactions of the N-terminal PAS domain of human PAS kinase using solution NMR methods. While this domain adopts a characteristic PAS fold, two regions are unusually flexible in solution.

Coordinate regulation of sugar flux and translation by PAS kinase.

PAS kinase is a serine/threonine kinase regulated in cis by a PAS domain. A genetic study of the two PAS kinase genes in budding yeast gave evidence of the involvement of these enzymes in the control of sugar metabolism and translation. Using a biochemical screen for PAS kinase substrates, three translation factors were identified as direct phosphorylation targets.

Metabolism and the control of circadian rhythms.

The core apparatus that regulates circadian rhythm has been extensively studied over the past five years. A looming question remains, however, regarding how this apparatus is adjusted to maintain coordination between physiology and the changing environment. The diversity of stimuli and input pathways that gain access to the circadian clock are summarized.

Efficiency of DNA pooling to estimate joint allele frequencies and measure linkage disequilibrium.

Pooling DNA samples can yield efficient estimates of the prevalence of genetic variants. We extend methods of analyzing pooled DNA samples to estimate the joint prevalence of variants at two or more loci. If one has a sample from the general population, one can adapt the method for joint prevalence estimation to estimate allele frequencies and D, the measure of linkage disequilibrium.

Synergistic induction of matrix metalloproteinase 1 by interleukin-1alpha and oncostatin M in human chondrocytes involves signal transducer and activator of transcription and activator protein 1 transcription factors via a novel mechanism.

Objective: To investigate the mechanism of interleukin-1alpha (IL-1alpha) and oncostatin M (OSM) synergistic regulation of matrix metalloproteinase 1 (MMP-1) in human chondrocytes.

Methods: Using an immortalized human chondrocyte cell line (T/C28a4), we investigated regulation of the MMP-1 gene. Northern blotting and flow cytometric analysis were used to assess changes in receptor, MMP-1, and c-fos expression.

PAS kinase: an evolutionarily conserved PAS domain-regulated serine/threonine kinase.

PAS domains regulate the function of many intracellular signaling pathways in response to both extrinsic and intrinsic stimuli. PAS domain-regulated histidine kinases are common in prokaryotes and control a wide range of fundamental physiological processes. Similarly regulated kinases are rare in eukaryotes and are to date completely absent in mammals.

Regulation of clock and NPAS2 DNA binding by the redox state of NAD cofactors.

Clock:BMAL1 and NPAS2:BMAL1 are heterodimeric transcription factors that control gene expression as a function of the light-dark cycle. Although built to fluctuate at or near a 24-hour cycle, the clock can be entrained by light, activity, or food. Here we show that the DNA-binding activity of the Clock:BMAL1 and NPAS2:BMAL1 heterodimers is regulated by the redox state of nicotinamide adenine dinucleotide (NAD) cofactors in a purified system.

Collection of genomic DNA from adults in epidemiological studies by buccal cytobrush and mouthwash.

Blood samples are an excellent source of large amounts of genomic DNA. However, alternative sources are often needed in epidemiological studies because of difficulties in obtaining blood samples. This report evaluates the buccal cytobrush and alcohol-containing mouthwash protocols for collecting DNA by mail.

Manganese superoxide dismutase signals matrix metalloproteinase expression via H2O2-dependent ERK1/2 activation.

Manganese-superoxide dismutase (Sod2) removes mitochondrially derived superoxide (O(2)) at near-diffusion limiting rates and is the only antioxidant enzyme whose expression is regulated by numerous stimuli. Here it is shown that Sod2 also serves as a source of the intracellular signaling molecule H(2)O(2). Sod2-dependent increases in the steady-state levels of H(2)O(2) led to ERK1/2 activation and subsequent downstream transcriptional increases in matrix metalloproteinase-1 (MMP-1) expression, which were reversed by expression of the H(2)O(2)-detoxifying enzyme, catalase.

Loss of heterozygosity on chromosome 11q22-23 in melanoma is associated with retention of the insertion polymorphism in the matrix metalloproteinase-1 promoter.

Matrix metalloproteinase-1 (MMP-1, collagenase-1), which degrades interstitial collagen, is expressed at high levels by some tumor cells and is thought to enhance their invasiveness and metastatic potential. We recently described a common single nucleotide insertion polymorphism (2G allele) at -1,607 bp in the promoter of the MMP-1 gene that creates a binding site for the ETS family of transcription factors, and that is associated with enhanced transcription of this gene and increased enzyme activity. Allelic loss at the MMP-1 locus on chromosome 11 occurs in many tumors including melanoma, an invasive and aggressive cancer.

Interstitial collagenases as markers of tumor progression.

Degradation of the extracellular matrix is the sine qua non of tumor invasion and metastasis. Most of this degradation is mediated by matrix metalloproteinases (MMPs), a family of enzymes that, collectively, degrades the extracellular matrix. Although the basement membrane-degrading enzymes, MMP-2 and MMP-9, have been given considerable attention for their roles in invasion and metastasis, the interstitial collagenases, a subfamily of MMPs that cleaves the stromal collagens types I and III, have received relatively little recognition for their part in these processes.

Impaired cued and contextual memory in NPAS2-deficient mice.

Neuronal PAS domain protein 2 (NPAS2) is a basic helix-loop-helix (bHLH) PAS domain transcription factor expressed in multiple regions of the vertebrate brain. Targeted insertion of a beta-galactosidase reporter gene (lacZ) resulted in the production of an NPAS2-lacZ fusion protein and an altered form of NPAS2 lacking the bHLH domain. The neuroanatomical expression pattern of NPAS2-lacZ was temporally and spatially coincident with formation of the mature frontal association/limbic forebrain pathway.

Synthesis of highly potent second-generation taxoids through effective kinetic resolution coupling of racemic beta-lactams with baccatins.

A series of highly potent second-generation taxoids bearing a 2-methylprop-1-enyl or a 2-methylpropyl group at C-3' with modifications at the C-2, C-10, and C-14 positions was synthesized through the coupling of racemic cis-beta-lactams with properly protected/modified baccatin and 14-OH-baccatin. A high level of kinetic resolution was observed for all cases examined. The observed highly efficient enantiomer differentiation is ascribed to the markedly different chiral environment between the (+)- and (-)-beta-lactams in their approach to the chiral framework of the enantiopure lithium alkoxide of a baccatin in the ring-opening coupling process.

A novel host/tumor cell interaction activates matrix metalloproteinase 1 and mediates invasion through type I collagen.

Along with degradation of type IV collagen in basement membrane, destruction of the stromal collagens, types I and III, is an essential step in the invasive/metastatic behavior of tumor cells, and it is mediated, at least in part, by interstitial collagenase 1 (matrix metalloproteinase 1 (MMP-1)). Because A2058 melanoma cells produce substantial quantities of MMP-1, we used these cells as models for studying invasion of type I collagen. With a sensitive and quantitative in vitro invasion assay, we monitored the ability of these cells to invade a matrix of type I collagen and the ability of a serine proteinase inhibitor and all-trans-retinoic acid to block invasion.

Subtotal adrenalectomy for phaeochromocytoma in multiple endocrine neoplasia type 2A.

Objective: To describe our surgical technique for, and results of, subtotal adrenalectomy for phaeochromocytoma in multiple endocrine neoplasia (MEN) type 2.

Design: Retrospective study.

Setting: Teaching hospital, The Netherlands.

Retinoid-mediated suppression of tumor invasion and matrix metalloproteinase synthesis.

Cancer mortality usually results from the tumor invading the local environment and metastasizing to vital organs, e.g. liver, lung, and brain.