Role of the histone deacetylase complex in acute promyelocytic leukaemia

Non-liganded retinoic acid receptors (RARs) repress transcription of target genes by recruiting the histone deacetylase complex through a class of silencing mediators termed SMRT or N-CoR. Mutant forms of RARalpha, created by chromosomal translocations with either the PML (for promyelocytic leukaemia) or the PLZF (for promyelocytic leukaemia zinc finger) locus, are oncogenic and result in human acute promyelocytic leukaemia (APL). PML-RARalpha APL patients achieve complete remission following treatments with pharmacological doses of retinoic acids (RA); in contrast, PLZF-RARalpha patients respond very poorly, if at all. Here we report that the association of these two chimaeric receptors with the histone deacetylase (HDAC) complex helps to determine both the development of APL and the ability of patients to respond to retinoids. Consistent with these observations, inhibitors of histone deacetylase dramatically potentiate retinoid-induced differentiation of RA-sensitive, and restore retinoid responses of RA-resistant, APL cell lines. Our findings suggest that oncogenic RARs mediate leukaemogenesis through aberrant chromatin acetylation, and that pharmacological manipulation of nuclear receptor co-factors may be a useful approach in the treatment of human disease.

Comparative Study on Adhesive Performance of Functional Monomers

Mild self-etch adhesives demineralize dentin only partially, leaving hydroxyapatite around collagen within a submicron hybrid layer. We hypothesized that this residual hydroxyapatite may serve as a receptor for chemical interaction with the functional monomer and, subsequently, contribute to adhesive performance in addition to micro-mechanical hybridization. We therefore chemically characterized the adhesive interaction of 3 functional monomers with synthetic hydroxyapatite, using x-ray photoelectron spectroscopy and atomic absorption spectrophotometry. We further characterized their interaction with dentin ultra-morphologically, using transmission electron microscopy. The monomer 10-methacryloxydecyl dihydrogen phosphate (10-MDP) readily adhered to hydroxyapatite. This bond appeared very stable, as confirmed by the low dissolution rate of its calcium salt in water. The bonding potential of 4-methacryloxyethyl trimellitic acid (4-MET) was substantially lower. The monomer 2-methacryloxyethyl phenyl hydrogen phosphate (phenyl-P) and its bond to hydroxyapatite did not appear to be hydrolytically stable. Besides self-etching dentin, specific functional monomers have additional chemical bonding efficacy that is expected to contribute to their adhesive potential to tooth tissue.

Metalloproteinase-mediated release of human Fas ligand

Fas ligand (FasL) is a type II integral membrane protein homologous with tumor necrosis factor (TNF). Recent studies indicate that TNF is processed to yield the soluble cytokine by metalloproteinases at the cell surface of activated macrophages and T cells. In the present study, we investigated whether FasL is also released by metalloproteinases. Treatment with hydroxamic acid inhibitors of matrix metalloproteinases specifically led to accumulation of membrane-type FasL (p40) on the surface of human FasL cDNA transfectants and activated human T cells, as estimated by surface immunofluorescence and immunoprecipitation with newly established anti-human FasL monoclonal antibodies. This surface accumulation of mFasL was associated with the decrease of soluble FasL (p27) in the supernatant as estimated by quantitative ELISA and immunoprecipitation with anti-human FasL monoclonal antibodies. These results indicate that human FasL is efficiently released from the cell surface by metalloproteinases like TNF.

Silk fibroin of Bombyx mori is secreted, assembling a high molecular mass elementary unit consisting of H-chain, L-chain, and P25, with a 6:6:1 molar ratio

Silk fibroin produced by the silkworm Bombyx mori consists of a heavy chain, a light chain, and a glycoprotein, P25. The heavy and light chains are linked by a disulfide bond, and P25 associates with disulfide-linked heavy and light chains by noncovalent interactions. Quantitative enzyme-linked immunosorbent assay revealed that molar ratios of the heavy chain, light chain, and P25 were 6:6:1, both in cocoons and in fibroin secreted into the lumen of posterior silk gland. Trace amounts of fibroin produced by three "naked pupa" mutants of B. mori lacked the light chain, but the molar ratio of heavy chain and P25 was also 6:1. Gel filtration chromatography and sedimentation equilibrium analysis demonstrated that a large protein complex of approximately 2.3 MDa, designated an elementary unit of fibroin having 6:6:1 molar ratios of the heavy chain, light chain, and P25, existed in posterior silk gland cells. Inaccessibility of biotinylated concanavalin A to the native elementary unit and partial dissociation of the elementary unit after incubation with excess N-glycosidase F or endoglycosidase H suggest that a single molecule of P25 is located internally and plays an important role in maintaining integrity of the complex.

The Palliative Prognostic Index: a scoring system for survival prediction of terminally ill cancer patients

Although accurate prediction of survival is essential for palliative care, few clinical methods of determining how long a patient is likely to live have been established. To develop a validated scoring system for survival prediction, a retrospective cohort study was performed with a training-testing procedure on two independent series of terminally ill cancer patients. Performance status (PS) and clinical symptoms were assessed prospectively. In the training set (355 assessments on 150 patients) the Palliative Prognostic Index (PPI) was defined by PS, oral intake, edema, dyspnea at rest, and delirium. In the testing sample (233 assessments on 95 patients) the predictive values of this scoring system were examined. In the testing set, patients were classified into three groups: group A (PPI< or =2.0), group B (2.0<PPI< or =4.0), and group C (PPI>4.0). Group B survived significantly longer than group C, and group A survived significantly longer than either of the others. Also, when a PPI of more than 6 was adopted as a cut-off point, 3 weeks' survival was predicted with a sensitivity of 80% and a specificity of 85%. When a PPI of more than 4 was used as a cutoff point, 6 weeks' survival was predicted with a sensitivity of 80% and a specificity of 77%. In conclusion, whether patients live longer than 3 or 6 weeks can be acceptably predicted by PPI.

Interaction of phytoestrogens with estrogen receptors alpha and beta

The human estrogen receptor (hER) exists as two subtypes, hER alpha and hER beta, that differ in the C-terminal ligand-binding domain and in the N-terminal transactivation domain. In this study, we investigated the estrogenic activities of soy isoflavones after digestion with enteric bacteria in competition binding assays with hER alpha or hER beta protein, and in a gene expression assay using a yeast system. The estrogenic activities of these isoflavones were also investigated by the growth of MCF-7 breast cancer cells. Isoflavone glycoside binds weakly to both receptors and estrogen receptor-dependent transcriptional expression is poor. The aglycones bind more strongly to hER beta than to hER alpha. The binding affinities of genistein, dihydrogenistein and equol are comparable to the binding affinity of 17 beta-estradiol. Equol induces transcription most strongly with hER alpha and hER beta. The concentration required for maximal gene expression is much higher than expected from the binding affinities of the compounds, and the maximal activity induced by these compounds is about half the activity of 17 beta-estradiol. Although genistin binds more weakly to the receptors and induces transcription less than does genistein, it stimulates the growth of MCF-7 cells more strongly than does genistein.

Association of bone mineral density with polymorphism of the estrogen receptor gene

PvuII and XbaI restriction fragment length polymorphisms (RFLPs) of the estrogen receptor (ER) gene and its relation to bone mineral density (BMD) were examined in 238 postmenopausal healthy women aged 45-91 years (66.3 +/- 0.6 years, mean +/- standard error of the mean [SEM]) in Japan. The RFLPs were represented as Pp (PvuII) and Xx (XbaI), with capital letters signifying the absence of and small letters the presence of restriction sites. In the PPxx genotype (n = 18), Z score values of BMD were significantly lower than those for other genotypes (n = 220) (lumbar spine, -0.746 vs. -0.065 [p = 0.022]; total body, -0.482 vs. 0.308 [p = 0.002]). We classified the subjects into three genotypes with allelic haplotype: homozygote of the Px haplotype was expressed as the 11 genotype, heterozygote of the Px haplotype as the 10 genotype, and the one lacking the Px haplotype as the 00 genotype. The PpXx genotype was not included in this analysis because the allelic haplotypes are uncertain. The Px haplotype was associated with a low BMD in postmenopausal women (Z score for the lumbar spine, -0.746 vs. -0.279 vs. 0.083, for the 11, 10, 00 genotypes, respectively [p = 0.029]; Z score for the total body, -0.482 vs. 0.164 vs. 0.427, respectively [p = 0.003]). We suggest that some variation of the ER gene linked to these RFLPs is associated with low BMD and that this at least partly explains the cause of postmenopausal osteoporosis in Japanese women.

Four-year water degradation of total-etch adhesives bonded to dentin

Resin-dentin bonds degrade over time. The objective of this study was to evaluate the influence of variables like hybridization effectiveness and diffusion/elution of interface components on degradation. Hypotheses tested were: (1) There is no difference in degradation over time between two- and three-step total-etch adhesives; and (2) a composite-enamel bond protects the adjacent composite-dentin bond against degradation. The micro-tensile bond strength (microTBS) to dentin of 2 three-step total-etch adhesives was compared with that of 2 two-step total-etch adhesives after 4 years of storage in water. Quantitative and qualitative failure analyses were conducted correlating Fe-SEM and TEM. Indirect exposure to water did not significantly reduce the microTBS of any adhesive, while direct exposure resulted in a significantly reduced microTBS of both two-step adhesives. It is concluded that resin bonded to enamel protected the resin-dentin bond against degradation, while direct exposure to water for 4 years affected bonds produced by two-step total-etch adhesives.

The complete primary structure of human estrogen receptor beta (hER beta) and its heterodimerization with ER alpha in vivo and in vitro

Human estrogen receptor beta (hER beta) cDNA that encodes the full-length amino acid sequence has been isolated from testis poly(A)+ RNA with the combination of cDNA screening and reverse transcription-PCR. It is composed of a 1590-bp open reading frame and a segment of the 5'- and 3'-untranslated region (UTR) and encodes an additional 53 amino acids in the N-terminal region compared with the previously reported one. Protein interaction between ER alpha and ER beta was demonstrated in vitro by GST pull-down assay and in vivo by immunoprecipitation. Thus, this study indicates that ER alpha and ER beta can interact in vivo, cross-signaling each other.

Molecular cloning and characterization of human estrogen receptor betacx: a potential inhibitor ofestrogen action in human

We have identified and characterized a novel human estrogen receptor (ER) beta isoform, ERbetacx, which is truncated at the C-terminal region but has an extra 26 amino acids due to alternative splicing. The ERbetacx transcript is expressed in testis, ovary, thymus and prostate as well as in human cultured cell lines such as HEC-1, HOS-TE85 and Saos-2 cells. ERbetacx protein is also immunodetectable in these human cells. Biochemical analysis reveals that the average dissociation constants ( K d) of ERalpha and ERbeta for 17beta-estradiol (E2) are 0.2 and 0.6 nM respectively, but ERbetacx has no ligand binding ability. ERalpha and ERbeta proteins bind to the estrogen response element, whereas ERbetacx does not form any shifted complex in gel shift assays. In a transient expression assay, ERbetacx shows no ligand-dependent transactivation ability of a basal promoter and also cannot interact with a cofactor, TIF1alpha, in the presence or absence of E2. ERbetacx preferentially forms a heterodimer with ERalpha rather than that with ERbeta, inhibiting DNA binding by ERalpha. Interestingly, however, it shows a significant dominant negative activity only against ERalpha transactivation. Thus, this study indicates that ERbetacx potentially inhibits ERalpha-mediated estrogen action and that alternative splicing of the C-terminal region and its inhibitory properties are characteristic of several members of nuclear receptor isoforms.

Oxidative DNA damage induced by simultaneous generation of nitric oxide and superoxide

Incubation of calf thymus DNA with 3-morpholinosydnonimine (SIN-1), which simultaneously generates nitric oxide (NO) and superoxide (O2-), induced a significant increase of 8-hydroxydeoxyguanosine (8-OH-dG). Peroxynitrite also increased 8-OH-dG in calf thymus DNA. Addition of free hydroxyl radical (.OH) scavengers inhibited the increase of 8-OH-dG by SIN-1 or peroxynitrite. Incubation of 32P-labeled DNA fragment with SIN-1 or peroxynitrite caused DNA cleavage at every nucleotide with a little dominance at guanine residues. The results suggest that NO reacts with O2- to form peroxynitrite and the peroxynitrite induces oxidative DNA damage through an active intermediate of which reactivity is similar to .OH.

Monomer-solvent phase separation in one-step self-etch adhesives

One-step adhesives bond less effectively to enamel/dentin than do their multi-step versions. To investigate whether this might be due to phase separation between adhesive ingredients, we characterized the interaction of 5 experimental and 3 commercial self-etch adhesives with dentin using transmission electron microscopy. All adhesives were examined for homogeneity by light microscopy. Bonding effectiveness to dentin was determined with the use of a micro-tensile bond-strength protocol. The lower bond strength of the one-step adhesives was associated with light-microscopic observation of multiple droplets that disappeared slowly. Interfacial analysis confirmed the entrapment of droplets within the adhesive layer. The prompt disappearance of droplets upon application of a small amount of HEMA (2-hydroxyethyl methacrylate) or a HEMA-containing bonding agent, as well as the absence of droplets at the interface of all HEMA-containing adhesives, strongly suggests that the adhesive monomers separate from water upon evaporation of ethanol/acetone. Upon polymerization, the droplets become entrapped within the adhesive, potentially jeopardizing bond durability. This can be avoided by strong air-drying of the adhesive, thereby removing interfacial water and thus improving bonding effectiveness.

Hepatic resection for hepatocellular carcinoma. Clinical features and long-term prognosis

Ninety-eight hepatic resections for hepatocellular carcinoma were performed on 94 patients from 1963-1985. HBs antigen was positive in 17% of patients, preoperative serum alpha-fetoprotein was more than 20 ng/mL in 70% of patients, and liver cirrhosis was present in 75% of patients. Hospital mortality rate was 19%, and the volume of operative blood loss was the most decisive factor that affected the short-term prognosis. Excluding the 19 hospital deaths, the long-term survival rates of 75 patients were 73%, 42%, and 25% for 1, 3, and 5 years, respectively. Prognostic factors that influenced the long-term prognosis were investigated by comparing the survival curves. Significant differences of survival patterns were noted when analyzed on the basis of preoperative alpha-fetoprotein level (less than or equal to 200 vs. greater than 200 ng/mL), tumor size (less than or equal to 5 vs. greater than 5 cm), and tumor capsule. The recurrence of carcinoma was the main cause of death in 56% (42 patients) who died after discharge from the hospital. The development of effective prevention and treatment against recurrent tumors is necessary to improve long-term prognosis.

Liquid-gated interface superconductivity on an atomically flat film

Liquid/solid interfaces are attracting growing interest not only for applications in catalytic activities and energy storage, but also for their new electronic functions in electric double-layer transistors (EDLTs) exemplified by high-performance organic electronics, field-induced electronic phase transitions, as well as superconductivity in SrTiO(3) (ref. 12). Broadening EDLTs to induce superconductivity within other materials is highly demanded for enriching the materials science of superconductors. However, it is severely hampered by inadequate choice of materials and processing techniques. Here we introduce an easy method using ionic liquids as gate dielectrics, mechanical micro-cleavage techniques for surface preparation, and report the observation of field-induced superconductivity showing a transition temperature T(c)=15.2 K on an atomically flat film of layered nitride compound, ZrNCl. The present result reveals that the EDLT is an extremely versatile tool to induce electronic phase transitions by electrostatic charge accumulation and provides new routes in the search for superconductors beyond those synthesized by traditional chemical methods.

The relationship between chronic hypoxemia and activation of the tumor necrosis factor-alpha system in patients with chronic obstructive pulmonary disease

Although circulating tumor necrosis factor (TNF)-alpha levels have been found to be increased in weight-losing patients with chronic obstructive pulmonary disease (COPD), the main causes for this phenomenon remain to be elucidated. Since hypoxia itself can enhance the production of the TNF-alpha in vitro, we studied the relationship between hypoxemia and activities of the TNF-alpha system, including circulating TNF-alpha and soluble TNF-receptors (sTNF-R; sTNF-R55 and -R75) levels, in 27 COPD patients and 15 age-matched healthy controls. The COPD patients showed a significant weight loss (body mass index = 18.1 +/- 2.8 versus 22.8 +/- 2.2 [mean +/- SD] kg/m(2); p < 0.0001. % fat = 16.3 +/- 5.9 versus 24.3 +/- 4.9 %; p < 0.001), and hypoxemia (Pa(O2 )= 62.2 +/- 9.5 versus 88.6 +/- 5.9 mm Hg; p < 0.0001) as compared with the healthy controls. Serum TNF-alpha (6.15 +/- 1.08 versus 5.41 +/- 1.60 pg/ml; p < 0.05) and plasma sTNF-R55 (1.15 +/- 0.49 versus 0.67 +/- 0.13 ng/ml; p < 0.0001) and sTNF-R75 (3.54 +/- 1.16 versus 2.25 +/- 0.43; p < 0.0001) levels were significantly higher in the COPD patients than in the healthy controls. There were inverse correlations between Pa(O(2)) and circulating TNF-alpha and sTNF-R levels in patients with COPD (TNF-alpha; r = -0.426, p = 0.0297; sTNF-R55: r = -0.587, p = 0.0027; sTNF-R75: r = -0.573, p = 0.0035). In addition, we found inverse correlations between sTNF-R levels and % fat in COPD patients (sTNF-R55: r = -0.442, p = 0.0272; sTNF-R75: r = -0. 484, p = 0.0155). TNF-alpha levels correlated well with sTNF-R levels (sTNF-R55: r = 0.488, p = 0.0127; sTNF-R75: r = 0.609, p = 0. 0019). These relationships were not observed in the healthy controls. These data suggest that systemic hypoxemia noted in patients with COPD is associated with activation of the TNF-alpha system in vivo, which may be a factor contributing to the weight loss in patients with the disease.

Twenty-year changes in the prevalence of overweight in Japanese adults: the National Nutrition Survey 1976-95

The aim of this study was to describe the 20-year changes in body mass index (BMI; kgm(-2)) and the prevalence of overweight in Japanese adults. Cross-sectional annual nationwide surveys (National Nutrition Survey, Japan) were carried out with a large probability sample of the Japanese population. Data sets of the 1976-95 surveys, comprising 91983 men and 120822 women (> or =20 years of age), were used. The analyses were carried out in age and gender groups, and by residential area according to the size of the municipality (metropolitan areas, cities and small towns). The mean BMI increaseed in men with an increment of +0.44 kg m(-2) 10 years(-1) and slightly decreased in women, by -0.09 kg m(-2) 10 years(-1), after adjustment for age. A decreasing trend of mean BMI was most significant in the female 20-29 years age-group (-0.38 kg m(-2) 10 years(-1)), in contrast to an increasing trend observed in elderly women (60-69 and 70+ years age-groups). The prevalence of preobese (BMI: 25-29.9kg m(-2)) and obese (BMI > or = 30 kg m(-2)) men increased from 14.5% and 0.8%, respectively, in the time-period 1976-80 to 20.5% and 2.01% during 1991-95. The increasing trend was most evident in the youngest age-group (20-29 years) and in those from small towns. The overall prevalence of preobese and obese women did not change during the 20-year study period. The prevalence in younger women decreased, this trend being more prominent in metropolitan areas. Although the prevalence of overweight (BMI > or =25 kg m(-2)) in Japanese men and elderly women has increased in the last 20 years, the mean BMI in younger women, especially those in metropolitan areas, has decreased. A population approach to control obesity and prevent obesity-associated diseases should be mainly focused on men and women older than 40 years of age.

Functional interaction between DNA-PK and c-Abl in response to DNA damage

How DNA damage is converted into intracellular signals that can control cell behaviour is unknown. The c-Abl protein tyrosine kinase is activated by ionizing radiation and certain other DNA-damaging agents, whereas the DNA-dependent protein kinase (DNA-PK), consisting of a serine/threonine kinase and Ku DNA-binding subunits, requires DNA double-strand breaks or other DNA lesions for activation. Here we demonstrate that c-Abl interacts constitutively with DNA-PK. Ionizing radiation stimulates binding of c-Abl to DNA-PK and induces an association of c-Abl with Ku antigen. We show that DNA-PK phosphorylates and activates c-Abl in vitro. Cells deficient in DNA-PK are defective in c-Abl activation induced by ionizing radiation. In a potential feedback mechanism, c-Abl phosphorylates DNA-PK, but not Ku, in vitro. Phosphorylation of DNA-PK by c-Abl inhibits the ability of DNA-PK to form a complex with DNA. We also show that treatment of cells with ionizing radiation results in phosphorylation of DNA-PK that is dependent on c-Abl. Our results support the hypothesis that there are functional interactions between c-Abl and DNA-PK in the response to DNA damage.

Hydrolytic Stability of Self-etch Adhesives Bonded to Dentin

Functional monomers chemically interact with hydroxyapatite that remains within submicron hybrid layers produced by mild self-etch adhesives. The functional monomer 10-MDP interacts most intensively with hydroxyapatite, and its calcium salt appeared most hydrolytically stable, as compared with 4-MET and phenyl-P. We investigated the hypothesis that additional chemical interaction of self-etch adhesives improves bond stability. The micro-tensile bond strength (μTBS) of the 10-MDP-based adhesive did not decrease significantly after 100,000 cycles, but did after 50,000 and 30,000 cycles, respectively, for the 4-MET-based and the phenyl-P-based adhesives. Likewise, the interfacial ultrastructure was unchanged after 100,000 thermocycles for the 10-MDP-based adhesive, while that of both the 4-MET- and phenyl-P-based adhesives contained voids and less-defined collagen. The findings of this study support the concept that long-term durability of adhesive-dentin bonds depends on the chemical bonding potential of the functional monomer.

Metabolic reprogramming during neuronal differentiation

Newly generated neurons pass through a series of well-defined developmental stages, which allow them to integrate into existing neuronal circuits. After exit from the cell cycle, postmitotic neurons undergo neuronal migration, axonal elongation, axon pruning, dendrite morphogenesis and synaptic maturation and plasticity. Lack of a global metabolic analysis during early cortical neuronal development led us to explore the role of cellular metabolism and mitochondrial biology during ex vivo differentiation of primary cortical neurons. Unexpectedly, we observed a huge increase in mitochondrial biogenesis. Changes in mitochondrial mass, morphology and function were correlated with the upregulation of the master regulators of mitochondrial biogenesis, TFAM and PGC-1α. Concomitant with mitochondrial biogenesis, we observed an increase in glucose metabolism during neuronal differentiation, which was linked to an increase in glucose uptake and enhanced GLUT3 mRNA expression and platelet isoform of phosphofructokinase 1 (PFKp) protein expression. In addition, glutamate-glutamine metabolism was also increased during the differentiation of cortical neurons. We identified PI3K-Akt-mTOR signalling as a critical regulator role of energy metabolism in neurons. Selective pharmacological inhibition of these metabolic pathways indicate existence of metabolic checkpoint that need to be satisfied in order to allow neuronal differentiation.

Atrium as a source of brain natriuretic polypeptide in patients with atrial fibrillation

BACKGROUND

Plasma brain natriuretic polypeptide (BNP) levels have been used as biochemical markers of systolic left ventricular (LV) dysfunction. Although in vitro studies have shown the existence of BNP messenger RNA in the atria, the main production site of BNP is believed to be the ventricle. The hypothesis that the atrium could be a source of BNP was examined in patients with lone atrial fibrillation (AF), the most common type of sustained arrhythmia.

METHODS AND RESULTS

We studied 16 controls and 21 patients with lone AF. Plasma samples for BNP were selectively and serially obtained from the aorta, anterior interventricular vein (AIV), and coronary sinus (CS). Atrial natriuretic polypeptide (ANP) levels were also measured to determine whether the CS samples contained significant amounts of atrial venous drainage. Of the 3 sample locations, the CS had the greatest ANP levels, confirming transcatheter sampling position accuracy. BNP levels were significantly greater in the CS than AIV in the patients with AF (279 +/- 226 v 126 +/- 97 pg/mL; P < .01). Consequently, plasma BNP levels were also greater in the patients with AF than controls (103 +/- 90 v 5 +/- 2 pg/mL; P < .001). LV ejection fraction was significantly less in patients with AF than control patients. Atrial production of BNP decreased significantly after successful DC cardioversion of AF in the 5 restudied patients (182 +/- 139 v 59 +/- 64 pg/mL; P < .05).

CONCLUSION

The data suggest that AF is a condition in which BNP is produced in the atrium itself.

Association of estrogen receptor dinucleotide repeat polymorphism with osteoporosis

We investigated the association between dinucleotide (thymine-adenine) repeat polymorphism lying upstream of human estrogen receptor (ER) gene and bone mineral density (BMD) as well as biochemical markers for bone metabolism in 144 healthy postmenopausal Japanese women. The genotype was classified into 'A' through 'R' according to the number of the repeats, from 10 to 27. BMD was expressed in Z score (a deviation from the weight-adjusted average BMD of each age using the standard deviation as a unit). The people having genotype C (12 repeats of thymine-adenine) allele (n = 15) had significantly lower Z score of spine BMD (mean +/- SD; -1.11 +/- 1.3 vs. -0.06 +/- 1.2; p < 0.01) and of total body BMD (-0.58 +/- 1.0 vs. 0.31 +/- 0.9; p < 0.01) than those without this genotype (n = 129). They also had significantly higher levels of serum intact osteocalcin, urinary pyridinoline, and urinary deoxypyridinoline. These results suggest that genetic variation at the ER locus may be associated with some determinants for BMD and bone metabolism in postmenopausal women.

TGF-β drives epithelial-mesenchymal transition through δEF1-mediated downregulation of ESRP

Epithelial-mesenchymal transition (EMT) is a crucial event in wound healing, tissue repair and cancer progression in adult tissues. We have recently shown that transforming growth factor (TGF)-β-induced EMT involves isoform switching of fibroblast growth factor receptors by alternative splicing. We performed a microarray-based analysis at single exon level to elucidate changes in splicing variants generated during TGF-β-induced EMT, and found that TGF-β induces broad alteration of splicing patterns by downregulating epithelial splicing regulatory proteins (ESRPs). This was achieved by TGF-β-mediated upregulation of δEF1 family proteins, δEF1 and SIP1. δEF1 and SIP1 each remarkably repressed ESRP2 transcription through binding to the ESRP2 promoter in NMuMG cells. Silencing of both δEF1 and SIP1, but not either alone, abolished the TGF-β-induced ESRP repression. The expression profiles of ESRPs were inversely related to those of δEF1 and SIP in human breast cancer cell lines and primary tumor specimens. Further, overexpression of ESRPs in TGF-β-treated cells resulted in restoration of the epithelial splicing profiles as well as attenuation of certain phenotypes of EMT. Therefore, δEF1 family proteins repress the expression of ESRPs to regulate alternative splicing during TGF-β-induced EMT and the progression of breast cancers.

Agonistic effect of tamoxifen is dependent on cell type, ERE-promoter context, and estrogen receptor subtype: functional difference between estrogen receptors alpha and beta

To investigate the functional differences between estrogen receptor (ER) alpha and beta subtypes, we studied the expression and the transcription stimulating activities of these receptors. RT-PCR has demonstrated that ER alpha is expressed at a high level in MCF-7 cells derived from human breast cancer. Both ER alpha and ER beta were expressed at a lower level in HOS-TE85 and Saos2 cells derived from human osteosarcoma. Chloramphenicol acetyltransferase reporter assay detected the transcriptional activation by the endogenous receptor only in MCF-7 cells. Agonistic effect of tamoxifen was observed as strong as that of 17beta-estradiol on ERE activation in MCF-7 cells at the concentration of 10(-7) M when ERE-containing reporter is constructed with beta-globin promoter. The effect of tamoxifen was not apparent when the reporter was constructed with thymidine kinase promoter, suggesting that the differential gene activation between tamoxifen and estrogen may take place depending upon ERE-promoter context. Agonistic activity of tamoxifen was also detected in COS-7 and Saos-2 cells, but not in HEC-1 cells derived from human endometrial carcinoma via exogenously expressed ER. Interestingly, this effect was ER alpha specific. Thus, we demonstrate that agonistic effect of tamoxifen depends on the cell type, ERE-promoter context, and ER subtype. These parameters would explain at least a part of the tissue specific effects of antiestrogens in vivo.

The alpha1-6-fucosyltransferase gene and its biological significance

GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha1-6-fucosyltransferase (alpha1-6FucT) catalyzes the transfer of fucose from GDP-Fuc to N-linked type complex glycoproteins. This enzyme was purified from a human fibroblast cell line, porcine brain, a human gastric cancer cell line and human blood platelets. cDNA cloning of porcine and human alpha1-6FucT was performed from a porcine brain and gastric cancer cell cDNA libraries, respectively. Their homology is 92.2% at the nucleotide level and 95.7% at the amino acid level. No putative N-glycosylation sites were found in the predicted amino acid sequence. No homology to other fucosyltransferases such as alpha1-2FucT, alpha1-3FucT and alpha1-4FucT was found except for a region consisting of nine amino acids. The alpha1-6FucT gene is located at chromosome 14q24.3, which is also a different location from other fucosyltransferases reported to date. The alpha1-6FucT gene is the oldest gene family in the phylogenic trees among the nine cloned fucosyltransferase genes. alpha1-6FucT is widely expressed in various rat tissues and the expression of alpha1-6FucT in the liver is enhanced during hepatocarcinogenesis of LEC rats which develop hereditary hepatitis and hepatomas. In cases of human liver diseases, alpha1-6FucT is expressed in both hepatoma tissues and their surrounding tissues with chronic liver disease, but not in the case of normal liver. Serum alpha1-6-fucosylated alpha-fetoprotein (AFP) has been employed for an early diagnosis of patients with hepatoma. The mechanisms by which alpha1-6 fucosylation of AFP occurs in the hepatoma is not due to the up-regulation of alpha1-6FucT alone. Interestingly, when the alpha1-6FucT gene is transfected into Hep3B, a human hepatoma cell line, tumor formation in the liver of nude mice after splenic injection is dramatically suppressed. In this review, we focus on alpha1-6FucT and summarize its properties, gene expression and biological significance.