다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Tight control of cell-cell communication is essential for the generation of a normally patterned embryo. A critical mediator of key cell-cell signaling events during embryogenesis is the highly conserved Wnt family of secreted proteins. Recent biochemical and genetic analyses have greatly enriched our understanding of how Wnts signal, and the list of canonical Wnt signaling components has exploded. The data reveal that multiple extracellular, cytoplasmic, and nuclear regulators intricately modulate Wnt signaling levels. In addition, receptor-ligand specificity and feedback loops help to determine Wnt signaling outputs. Wnts are required for adult tissue maintenance, and perturbations in Wnt signaling promote both human degenerative diseases and cancer. The next few years are likely to see novel therapeutic reagents aimed at controlling Wnt signaling in order to alleviate these conditions.

/pdf/the-wnt-signaling-pathway-in-development-and-disease-z4j8s29ao8.pdf

The Wnt signaling pathway in development and disease.

https://www.cell.com/cell/pdf/S0092-8674(00)81279-9.pdf

Cell Adhesion: The Molecular Basis of Tissue Architecture and Morphogenesis

The regulation of cell growth and survival can be subverted by a variety of genetic defects that alter transcriptional programs normally responsible for controlling cell number. High throughput analysis of these gene expression patterns should ultimately lead to the identification of minimal expression profiles that will serve as common denominators in assigning a cancer to a given category. In the course of defining the common denominators, though, we should not be too surprised to find that cancers within a single category may nevertheless exhibit seemingly disparate genetic defects. The wnt pathway has already provided an outstanding example of this. We now know of three regulatory genes in this pathway that are mutated in primary human cancers and several others that promote experimental cancers in rodents (Fig. 1). In all of these cases the common denominator is the activation of gene transcription by -catenin. The resulting gene expression profile should provide us with a signature common to those cancers carrying defects in the wnt pathway. In this review, the wnt pathway will be covered from the perspective of cancer, with emphasis placed on molecular defects known to promote neoplastic transformation in humans and in animal models.

/pdf/wnt-signaling-and-cancer-2fdsemer2h.pdf

Wnt signaling and cancer

▪ Abstract The prostaglandin endoperoxide H synthases-1 and 2 (PGHS-1 and PGHS-2; also cyclooxygenases-1 and 2, COX-1 and COX-2) catalyze the committed step in prostaglandin synthesis. PGHS-1 and 2 are of particular interest because they are the major targets of nonsteroidal anti-inflammatory drugs (NSAIDs) including aspirin, ibuprofen, and the new COX-2 inhibitors. Inhibition of the PGHSs with NSAIDs acutely reduces inflammation, pain, and fever, and long-term use of these drugs reduces fatal thrombotic events, as well as the development of colon cancer and Alzheimer's disease. In this review, we examine how the structures of these enzymes relate mechanistically to cyclooxygenase and peroxidase catalysis, and how differences in the structure of PGHS-2 confer on this isozyme differential sensitivity to COX-2 inhibitors. We further examine the evidence for independent signaling by PGHS-1 and PGHS-2, and the complex mechanisms for regulation of PGHS-2 gene expression.

Cyclooxygenases: Structural, cellular, and molecular biology

Several members of the Wnt family of secreted factors are strongly implicated as regulators of mammary cell growth and differentiation. To investigate Wnt signaling in mammary cells, we have assessed the abilities of 10 different Wnt genes to cause transformation of C57MG mammary epithelial cells and in parallel studied their effects on beta-catenin, a component of the Wnt-1 signaling pathway. Autocrine transforming potential was tested by expression of Wnt proteins in C57MG cells, and paracrine effects were evaluated by coculture of C57MG cells with fibroblasts secreting different Wnt proteins. Western blotting confirmed the expression of each Wnt protein in the relevant cell lines. Activities of the 10 Wnts tested were divisible into three groups. Wnt-1, Wnt-2, Wnt-3, and Wnt3a induced strong transformation and an elongated refractile cell morphology. Wnt-6 and Wnt-7a produced weak morphological changes. Wnt-4, Wnt-5a, Wnt-5b, and Wnt-7b had no effect at all on C57MG morphology. Analysis of beta-catenin levels showed that the transforming Wnts induced accumulation of cytosolic beta-catenin, whereas nontransforming Wnts did not. These result demonstrate that several Wnt family members are capable of elevating beta-catenin levels and suggest that their signaling pathways share intracellular signaling components. The correlation between increased cytosolic beta-catenin levels and C57MG transformation supports a role for beta-catenin in transformation of these cells. These data also imply the existence of receptors that respond to certain Wnt proteins but not to others.

http://cgd.aacrjournals.org/cgi/reprint/8/12/1349.pdf

Transformation by Wnt family proteins correlates with regulation of beta-catenin.

We have shown previously that an increase in the level of accumulated pS2 mRNA is first detectable in MCF-7 cells after 3 hr of estradiol treatment. Using in vitro nuclear run-on transcription with nuclei prepared from MCF-7 cells grown in the presence of estradiol or in estradiol-stripped medium, we demonstrate here that expression of the pS2 gene is controlled by estrogen at the transcriptional level. Induction of transcription is a very early event that is already apparent within 15 min after addition of estradiol to the culture medium. In addition, pretreatment of the cells with the protein synthesis inhibitor cycloheximide does not prevent induction of pS2 gene transcription, indicating that it corresponds to a primary effect of estrogen. The pS2 gene in MCF-7 cells represents a unique example of a human gene whose transcription is directly controlled by estrogen.

https://www.pnas.org/content/pnas/81/20/6344.full.pdf

Activation of pS2 gene transcription is a primary response to estrogen in the human breast cancer cell line MCF-7.

Gap junction channels composed of connexin43 (Cx43) are essential for normal heart formation and function. We studied the potential role of the Wnt family of secreted polypeptides as regulators of Cx43 expression and gap junction channel function in dissociated myocytes and intact hearts. Neonatal rat cardiomyocytes responded to Li+, which mimics Wnt signaling, by accumulating the effector protein β-catenin and by inducing Cx43 mRNA and protein markedly. Induction of Cx43 expression was also observed in cardiomyocytes cocultured with Rat-2 fibroblasts or N2A neuroblastoma cells programmed to secrete bioactive Wnt-1. By transfecting a Cx43 promoter-reporter gene construct into cardiomyocytes, we demonstrated that the inductive effect of Wnt signaling was transcriptionally mediated. Enhanced expression of Cx43 increased cardiomyocyte cell coupling, as determined by Lucifer Yellow dye transfer and by calcium wave propagation. Conversely, in a transgenic cardiomyopathic mouse model that exhibits ventricular arrhythmias and gap junctional remodeling, β-catenin and Cx43 expression were downregulated concordantly. In response to Wnt signaling, the accumulating Cx43 colocalized with β-catenin in the junctional membrane; moreover, forced expression of Cx43 in cardiomyocytes reduced the transactivation potential of β-catenin. These findings demonstrate that Wnt signaling is an important modulator of Cx43-dependent intercellular coupling in the heart, and they support the hypothesis that dysregulated signaling contributes to altered impulse propagation and arrhythmia in the myopathic heart.

/pdf/wnt-1-regulation-of-connexin43-in-cardiac-myocytes-2cteu4mk56.pdf

Wnt-1 regulation of connexin43 in cardiac myocytes

Cyclooxygenase-2 (COX-2), an inducible prostaglandin synthase, is normally expressed in parts of the kidney and brain. Aberrant COX-2 expression was first reported in colorectal carcinomas and adenomas, and has now been detected in various human cancers, including those of the breast. Strikingly, COX-2 overexpression in murine mammary gland is sufficient to cause tumour formation. To date, the role of COX-2 in tumorigenesis has been most intensively studied in the colon. Thus, the relationship between COX-2 and neoplasia can best be illustrated with reference to intestinal tumorigenesis. Here we consider the potential utility of selective COX-2 inhibitors for the prevention and treatment of breast cancer. Data for cancers of the colon and breast are compared where possible. In addition, the mechanisms by which COX-2 is upregulated in cancers and contributes to tumorigenesis are discussed. Importantly, several recent studies of mammary tumorigenesis in animal models have found selective COX-2 inhibitors to be effective in the prevention and treatment of breast cancer. Clinical trials will be needed to determine whether COX-2 inhibition represents a useful approach to preventing or treating human breast cancer. Endocrine-Related Cancer (2001) 8 97–114

/pdf/cyclooxygenase-2-a-target-for-the-prevention-and-treatment-2px687spf8.pdf

Anthony M. C. Brown

Papers

Transformation by Wnt family proteins correlates with regulation of beta-catenin.

Activation of pS2 gene transcription is a primary response to estrogen in the human breast cancer cell line MCF-7.

Wnt-1 regulation of connexin43 in cardiac myocytes

Cyclooxygenase-2: a target for the prevention and treatment of breast cancer.

A new nomenclature for int-1 and related genes: The Wnt gene family