Phenotype-directed analysis of genotype in early-onset, familial breast cancers

Considerable heterogeneity of morphology and disease outcome exists within breast cancers (BC), which likely reflects variable molecular pathogeneses within this broad clinical group.

AIM

To evaluate the underlying genomic alterations associated with familial, early-onset BC (EOBC) phenotypes, in order to improve the management of this disease.

METHODS

Using hierarchical clustering of morphological and immunophenotypical parameters, 116 EOBC were stratified into six groups. Conventional and array-based comparative genomic hybridisation was used to analyse the genomic alterations.

RESULTS

Specific areas of genomic imbalance were associated with individual phenotypes. The largest phenotypical group was high grade, oestrogen receptor and HER-2 negative. This group contained the majority of BRCA1 germline mutation-associated tumours and commonly showed loss of chromosomal regions 5cent-5q13, 5q14-22 and 4q28-32. High mitotic rate, an important indicator of tumour cell proliferation and poor prognosis, was associated with gain of 19p, mapped within 7 Mb of the telomere. This region contains the candidate oncogene CDC34, the protein product of which is involved in ubiquitin-mediated degradation of the cyclin-dependent kinase inhibitor, p27Kip1.

CONCLUSION

Phenotype-based analysis can be used to determine the genetic changes important in subtypes of BC. Further, the different morphological phenotypes could act as a cost-effective surrogate for genotypical stratification to facilitate optimal management of this disease.

Complex CGH alterations on chromosome arm 8p at candidate tumor suppressor gene loci in breast cancer cell lines

Loss of genetic material from chromosome arm 8p occurs frequently in human breast carcinomas, consistent with this region of the genome harboring one or more tumor suppressor genes (TSGs). We used the complementary techniques of microsatellite-based LOH, high-density FISH, and conventional CGH on 6 breast cancer cell lines (MCF7, SKBR3, T47D, MDA MB453, BT549, and BT474) to investigate the molecular cytogenetic changes occurring on chromosome 8 during tumorigenesis, with particular emphasis on 6 potential TSGs on 8p. We identified multiple alterations of chromosome 8, including partial or complete deletion of 8p or 8q, duplication of 8q, and isochromosome 8q. The detailed FISH analysis showed several complex rearrangements of 8p with differing breakpoints of varying proximity to the genes of interest. High rates of LOH were observed at markers adjacent to or within PCM1, DUSP4/MKP2, NKX3A, and DLC1, supporting their status as candidate TSGs. Due to the complex ploidy status of these cell lines, relative loss of 8p material detected by CGH did not always correlate with microsatellite-based LOH results. These results extend our understanding of the mechanisms accompanying the dysregulation of candidate tumor suppressor loci on chromosome arm 8p, and identify appropriate cellular systems for further investigation of their biological properties.

LCC15-MB cells are MDA-MB-435: a review of misidentified breast and prostate cell lines

Current stocks of the LCC15-MB cell line, which we originally isolated from a human breast-bone metastasis, were found to be genetically matched to the MDA-MB-435 cell line from the Lombardi Cancer Center (MDA-MB-435-LCC) using comparative genomic hybridisation, DNA microsatellite analysis and chromosomal number. LCC15-MB stocks used for our previously published studies as well as the earliest available LCC15-MB cells also showed identity to MDA-MB-435-LCC cells. The original karyotype reported for LCC15-MB cells was considerably different to that of MDA-MB-435 cells, indicating that the original LCC15-MB cells were lost to contamination by MDA-MB-435-LCC cells. Chromosome number is the simplest test to distinguish original LCC15-MB cells (n approximately 75) from MDA-MB-435 (n approximately 52). Collectively, our results prove that LCC15-MB cells currently available are MDA-MB-435 cells and we suggest their re-designation as MDA-MB-435-LCC15 cells. We also review the known misclassification of breast and prostate cancer cell lines to date and have initiated a register maintained at http://www.svi.edu.au/cell_lines_registry.doc.

Candidate tumor-suppressor genes on chromosome arm 8p in early-onset and high-grade breast cancers

Loss of genetic material from chromosome arm 8p occurs commonly in breast carcinomas, suggesting that this region is the site of one or more tumor-suppressor genes (TSGs). Comparative genomic hybridization analysis showed that 8p loss is more common in breast cancers from pre-menopausal compared with post-menopausal patients, as well as in high-grade breast cancers, regardless of the menopausal status. Subsequent high-resolution gene expression profiling of genes mapped to chromosome arm 8p, on an extended cohort of clinical tumor samples, indicated a similar dichotomy of breast cancer clinicopathologic types. Some of these genes showed differential downregulation in early-onset and later-onset, high-grade cancers compared with lower-grade, later-onset cancers. Three such genes were analysed further by in situ technologies, performed on tissue microarrays representing breast tumor and normal tissue samples. PCM1, which encodes a centrosomal protein, and DUSP4/MKP-2, which encodes a MAP kinase phosphatase, both showed frequent gene and protein loss in carcinomas. In contrast, there was an excess of cases showing loss of expression in the absence of reduced gene copy number of SFRP1, which encodes a dominant-negative receptor for Wnt-family ligands. These candidate TSGs may constitute some of the molecular drivers of chromosome arm 8p loss in breast carcinogenesis.

Detailed gene copy number and RNA expression analysis of the 17q12-23 region in primary breast cancers

Chromosome region 17q12-23 commonly shows an increase in DNA copy number in breast cancers, suggesting that several oncogenes are located at this site. We performed a high-resolution expression array and comparative genomic hybridization analysis of genes mapped to the entire 17q12-23 region, to identify novel candidate oncogenes. We identified 24 genes that showed significant overexpression in breast cancers with gain of 17q12-23, compared to cancers without gain. These genes included previously identified oncogenes, together with several novel candidate oncogenes. FISH analysis using specific gene probes hybridized to tissue arrays confirmed the underlying amplification of overexpressed genes. This high-resolution analysis of the 17q12-23 region indicates that several established and novel candidate oncogenes, including a Wnt-signaling pathway member, are amplified and overexpressed within individual primary breast cancer samples. We were also able to confirm the presence of two apparently separate and reciprocally amplified groups of genes within this region. Investigation of these genes and their functional interactions will facilitate our understanding of breast oncogenesis and optimal management of this disease.

Flaxseed consumption influences endogenous hormone concentrations in postmenopausal women

Lignans, similar in structure to endogenous sex steroid hormones, may act in vivo to alter hormone metabolism and subsequent cancer risk. The objective of this study was to examine effects of dietary intake of a lignan-rich plant food (flaxseed) on serum concentrations of endogenous hormones and binding proteins (estrone, estrone sulfate, 17 beta-estradiol, sex hormone-binding globulin, progesterone, prolactin, dehydroepiandrosterone sulfate, dehydroepiandrosterone, androstenedione, testosterone, and free testosterone) in postmenopausal women. This randomized, crossover trial consisted of three seven-week feeding periods, during which 28 postmenopausal women, aged 52-82 yr, consumed their habitual diets plus 0, 5, or 10 g of ground flaxseed. Serum samples collected during the last week of each feeding period were analyzed for serum hormones using standard diagnostic kits. The flaxseed diets significantly reduced serum concentrations of 17 beta-estradiol by 3.26 pg/ml (12.06 pmol/l) and estrone sulfate by 0.09 ng/ml (0.42 nmol/l) and increased prolactin by 1.92 micrograms/l (0.05 IU/ml). Serum concentrations of androstenedione, estrone, sex hormone-binding globulin, progesterone, testosterone, free testosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate were not altered with flaxseed feeding. In this group of postmenopausal women, consuming flaxseed in addition to their habitual diets influenced their endogenous hormone metabolism by decreasing serum 17 beta-estradiol and estrone sulfate and increasing serum prolactin concentrations.

Phosphoenolpyruvate synthetase from the hyperthermophilic archaeon Pyrococcus furiosus

Phosphoenolpyruvate synthetase (PpsA) was purified from the hyperthermophilic archaeon Pyrococcus furiosus. This enzyme catalyzes the conversion of pyruvate and ATP to phosphoenolpyruvate (PEP), AMP, and phosphate and is thought to function in gluconeogenesis. PpsA has a subunit molecular mass of 92 kDa and contains one calcium and one phosphorus atom per subunit. The active form has a molecular mass of 690+/-20 kDa and is assumed to be octomeric, while approximately 30% of the protein is purified as a large ( approximately 1.6 MDa) complex that is not active. The apparent K(m) values and catalytic efficiencies for the substrates pyruvate and ATP (at 80 degrees C, pH 8.4) were 0.11 mM and 1.43 x 10(4) mM(-1). s(-1) and 0.39 mM and 3.40 x 10(3) mM(-1) x s(-1), respectively. Maximal activity was measured at pH 9.0 (at 80 degrees C) and at 90 degrees C (at pH 8.4). The enzyme also catalyzed the reverse reaction, but the catalytic efficiency with PEP was very low [k(cat)/K(m) = 32 (mM. s(-1)]. In contrast to several other nucleotide-dependent enzymes from P. furiosus, PpsA has an absolute specificity for ATP as the phosphate-donating substrate. This is the first PpsA from a nonmethanogenic archaeon to be biochemically characterized. Its kinetic properties are consistent with a role in gluconeogenesis, although its relatively high cellular concentration ( approximately 5% of the cytoplasmic protein) suggests an additional function possibly related to energy spilling. It is not known whether interconversion between the smaller, active and larger, inactive forms of the enzyme has any functional role.

Key role for sulfur in peptide metabolism and in regulation of three hydrogenases in the hyperthermophilic archaeon Pyrococcus furiosus

The hyperthermophilic archaeon Pyrococcus furiosus grows optimally at 100 degrees C by the fermentation of peptides and carbohydrates. Growth of the organism was examined in media containing either maltose, peptides (hydrolyzed casein), or both as the carbon source(s), each with and without elemental sulfur (S(0)). Growth rates were highest on media containing peptides and S(0), with or without maltose. Growth did not occur on the peptide medium without S(0). S(0) had no effect on growth rates in the maltose medium in the absence of peptides. Phenylacetate production rates (from phenylalanine fermentation) from cells grown in the peptide medium containing S(0) with or without maltose were the same, suggesting that S(0) is required for peptide utilization. The activities of 14 of 21 enzymes involved in or related to the fermentation pathways of P. furiosus were shown to be regulated under the five different growth conditions studied. The presence of S(0) in the growth media resulted in decreases in specific activities of two cytoplasmic hydrogenases (I and II) and of a membrane-bound hydrogenase, each by an order of magnitude. The primary S(0)-reducing enzyme in this organism and the mechanism of the S(0) dependence of peptide metabolism are not known. This study provides the first evidence for a highly regulated fermentation-based metabolism in P. furiosus and a significant regulatory role for elemental sulfur or its metabolites.

Progressive genetic aberrations detected by comparative genomic hybridization in squamous cell cervical cancer

Genetic changes orchestrated by human papillomaviruses are the most important known factors in carcinogenesis of the uterine cervix. However, it is clear that additional genetic events are necessary for tumour progression. We have used comparative genomic hybridization to document non-random chromosomal gains and losses within a subset of 37 cervical carcinomas matched for clinical stage Ib, but with different lymph node status. There were significantly more chromosomal changes in the primary tumours when the lymph nodes were positive for metastases. The most frequent copy number alterations were loss of 3p, 11q, 6q and 10q and gain of 3q. The smallest areas of loss and gain on chromosome 3 were 3p14-22 and 3q24-26. The study identifies progressive DNA copy number changes associated with early-stage invasive cervical cancers with and without lymph node metastases, a factor of potential prognostic and therapeutic value.

Flaxseed influences urinary lignan excretion in a dose-dependent manner in postmenopausal women

Dietary estrogens, such as lignans, are similar in structure to endogenous sex steroid hormones and may act in vivo to alter hormone metabolism and subsequent cancer risk. The objective of this study was to examine the effect of dietary intake of a lignan-rich plant food (flaxseed) on urinary lignan excretion in postmenopausal women. This randomized, cross-over trial consisted of three 7-week feeding periods during which 31 healthy postmenopausal women, ages 52-82 years, consumed their habitual diets plus 0, 5, or 10 grams of ground flaxseed per day. Urine samples collected for 2 consecutive days during the last week of each feeding period were analyzed for lignan content (enterodiol, enterolactone, and matairesinol) by isotope dilution gas chromatography/mass spectrometry. Compared with the 0-gram flaxseed diet, consumption of 5 or 10 grams of flaxseed significantly increased excretion of enterodiol by 1,009 and 2,867 nmol/day, respectively; significantly increased excretion of enterolactone by 21,242 and 52,826 nmol/day, respectively; and significantly increased excretion of total lignans (enterodiol + enterolactone + matairesinol) by 24,333 and 60,640 nmol/day, respectively. Excretion of matairesinol was not significantly altered by flaxseed consumption. Consumption of flax, a significant source of dietary estrogens, in addition to their habitual diets increased excretion of enterodiol and enterolactone, but not matairesinol, in a dose-dependent manner in this group of postmenopausal women. Urinary excretion of lignan metabolites is a dose-dependent biomarker of flaxseed intake within the context of a habitual diet.

MAGE-12 and MAGE-6 are frequently expressed in malignant melanoma

MAGE proteins have been identified as potential specific targets for cancer vaccination. Although MAGE-6 and MAGE-12 were originally identified in malignant melanoma there are no studies reporting the frequency of expression of these antigens in this malignancy. These are of relevance particularly for MAGE-6 as recent studies have identified CTL activity against several epitopes. We have studied MAGE-1, -2, -3, -4, -6 and -12 gene expression using reverse transcription-polymerase chain reaction in 47 melanoma samples and 11 melanoma cell lines established from these tumours. The tumour samples expressed MAGE-12 (74%) and MAGE-6 (64%) mRNA at much higher frequencies than the other MAGE genes. MAGE-12 and MAGE-6 were expressed at the highest frequencies, relative to the other MAGE antigens, in early stage lesions. The frequency of expression of all the MAGE genes was found to be higher in samples from metastatic deposits compared to those from locoregional disease. The cell lines all expressed the same or more MAGE antigens than the tumours from which they were derived. In only one cell line was expression of a MAGE antigen lost. Certain recurring patterns of MAGE expression were observed in the tumour samples. MAGE-6 and/or -12 expression were detected in all of those 26 tumour samples that were positive for one or more of MAGE-1, -2, -3 and -4. Twenty of these 26 samples expressed both antigens. These findings suggest that protocols targeting MAGE-12 and -6 would permit many more patients to be included into clinical cancer vaccination trials.

Urinary isoflavonoid and lignan excretion on a Western diet: relation to soy, vegetable, and fruit intake

Dietary isoflavone and lignan phytoestrogens are potential chemopreventive agents. This has led to a need to monitor exposure to these compounds in human populations and to determine which components of a mixed diet contribute to the exposure. Typically, urinary isoflavonoid excretion is associated with soy consumption and that of lignans is associated with whole grains. However, other plant foods are known to contain phytoestrogen precursors. The purpose of this study was to examine the association between urinary isoflavonoid and lignan excretion and intakes of vegetables and fruits (V&F). Isoflavonoids (genistein, daidzein, O-desmethylangolensin, and equol) and lignans (enterolactone, enterodiol, and matairesinol) were measured in urine collected for 3 days from 49 male and 49 female volunteers (age, 18-37 years) reporting a wide range of habitual V&F intakes. Dietary intakes were assessed using 5-day diet records and a food frequency questionnaire. V&F groupings (total V&F, total V, total F, soyfoods, and V&F grouped by botanical families) were used to assess the relationship between V&F intake and urinary isoflavonoid and lignan excretion. Pearson correlations were performed. Intake of soyfoods was correlated significantly with urinary genistein (r = 0.40; P = 0.0001), O-desmethylangolensin (r = 0.37; P = 0.0002), daidzein (r = 034; P = 0.0007), and the sum of isoflavonoids (r = 0.39; P = 0.0001). There was no association between equol excretion and soy intake or between the isoflavonoids and any other V&F groupings. In addition, isoflavonoid excretion was correlated positively with intake of high-fat and processed meats, particularly among men who did not consume soy. This suggests that, even in the United States, on a Western diet, soyfoods are the primary contributors to isoflavone intake; however, additional "hidden sources" of soy may also contribute to exposure. In contrast, a variety of fiber-containing foods contributed to lignan excretion; the sum of the urinary lignans, enterodiol, enterolactone, and matairesinol, was associated with intake of total F (r = 0.27; P = 0.008), total V&F (r = 0.25; P = 0.01), soyfoods (r = 0.28; P = 0.006), and dietary fiber (r = 0.36; P = 0.0003). Overall, urinary phytoestrogens (isoflavonoids + lignans) were significantly higher in "high" compared with "low" V&F consumers. Compared with the "low" V&F group, the "high" group consumed diets that were, on average, higher in fiber and carbohydrate and soyfoods and lower in fat; thus, the urinary phytoestrogens may also be a useful marker of healthier dietary patterns.

Effect of flaxseed consumption on urinary estrogen metabolites in postmenopausal women

Flaxseed, the richest known source of plant lignans, has been shown to have chemoprotective effects in animal and cell studies. Some of its effects may be mediated through its influence on endogenous hormone production and metabolism. Two competing pathways in estrogen metabolism involve production of the 2-hydroxylated and 16 alpha-hydroxylated metabolites. Because of the proposed differences in biological activities of these metabolites, the balance of the two pathways has been used as a biomarker for breast cancer risk. We examined the effects of flaxseed consumption on urinary estrogen metabolite excretion in postmenopausal women. Twenty-eight postmenopausal women were studied for three seven-week feeding periods in a randomized crossover design. During the feeding periods, subjects consumed their usual diets plus ground flaxseed (0, 5, or 10 g/day). Urinary excretion of the estrogen metabolites 2-hydroxyestrogen (2-OHEstrogen) and 16 alpha-hydroxyestrone (16 alpha-OHE1) as well as their ratio, 2/16 alpha-OHE1, was measured by enzyme immunoassay. Flaxseed supplementation significantly increased urinary 2-OHEstrogen excretion (p < 0.0005) and the urinary 2/16 alpha-OHE1 ratio (p < 0.05) in a linear, dose-response fashion. There were no significant differences in urinary 16 alpha-OHE1 excretion. These results suggest that flaxseed may have chemoprotective effects in postmenopausal women.

Distinct molecular pathogeneses of early-onset breast cancers in BRCA1 and BRCA2 mutation carriers: a population-based study

Breast cancers arising in women with and without a germline mutation in the BRCA1 or BRCA2 gene display different histological features, which suggests unique mechanisms of molecular pathogenesis: We used a molecular pathological analysis to define the genetic abnormalities relevant to these specific pathogeneses. Tumor material was studied from 40 women with breast cancer diagnosed before 40 years of age, sampled from a population-based study and stratified by BRCA1 and BRCA2 germline mutation status. Cases were not selected for family history or ethnic origin, and none were known to be genetically related. Thus, germline mutation itself is likely to impact on the molecular pathogenesis of these tumors, with no substantial influence due to modifying genetic or environmental factors. Breast cancers occurring in BRCA1 mutation carriers had significantly higher levels of p53 expression, including the preinvasive (carcinoma in situ) stage of disease, compared with cancers occurring in BRCA2 mutation carriers or women with no detectable germline mutation. These cancers also had a higher proliferation rate as measured by Ki-67 antibody. Expression of the prognostic factors c-erbB-2, cyclin D1, and estrogen receptor was significantly less common in BRCA1 mutation carriers. Lower levels of cyclin D1 were also found in cancers from BRCA2 mutation carriers compared with non-mutation carriers. Direct p53 mutation analysis revealed mutations in 18% of all of the early-onset breast cancers within the study and included rare insertion and deletional mutations in cancers from BRCA1 mutation carriers. Our data indicate that a BRCA1 breast cancer phenotype may be recognized by an exceptionally high proliferation rate and early and frequent p53 overexpression but infrequent selection for overexpression of several other prognostic factor proteins known to be involved in breast oncogenesis. In contrast, breast cancers arising in BRCA2 mutation carriers have a more heterogeneous phenotypic profile.

Influence of soybean processing, habitual diet, and soy dose on urinary isoflavonoid excretion

In an attempt to explain the wide individual variation seen in urinary isoflavonoid phytoestrogen excretion, we conducted a series of 3 human feeding studies: a large cross-sectional study of equol production in humans with a soy challenge, a comparison of phytoestrogen metabolism when subjects consumed fermented and unfermented soy products, and a dose-response study of urinary isoflavonoid excretion at the low end of soy consumption. All studies were conducted in young, healthy humans. Urinary isoflavonoids were measured by isotope-dilution gas chromatography-mass spectrometry. Similar to results from other studies, 35% of screened subjects (30 men and 30 women) excreted equol (>2000 nmol/d). In women, equol excretion was associated with higher intake of dietary fiber and carbohydrate. Fermentation of soy decreased the isoflavone content of the product fed but increased the urinary isoflavonoid recovery, suggesting that fermentation increases availability of isoflavones in soy. When soy-protein powder was fed at 0, 5, 10, and 20 g/d (0-36 mg isoflavones), there was a linear dose response of urinary isoflavonoid excretion to soy consumption that did not differ between subjects with high and low equol excretion. These results suggest that equol excretion may be related to the fermentable carbohydrate content of the diet; additional study is needed. Processing of soy affects isoflavone metabolism and must be considered in recommending exposure to isoflavones from soyfoods. Although optimal isoflavone exposure for disease protection has not been determined, urinary isoflavonoid excretion appears linear at low-to-moderate soy consumption.

Urinary equol excretion with a soy challenge: influence of habitual diet

Equol is an isoflavonoid phytoestrogen produced from the soy isoflavone daidzein by gut microflora. Not all humans produce equol from daidzein, presumably due to differences in colonic bacterial populations among individuals. Previously, smaller studies reported that approximately 30% of participants excreted equol when consuming soy. The purpose of our study was to determine the prevalence of equol excreters in a larger sample and to examine what dietary components might influence the tendency to be an equol excreter. Thirty men and thirty women consumed a soy protein beverage containing 22 mg genistein and 8 mg daidzein for 4 days as a supplement to their habitual diets. The mean daily nutrient content of their habitual intakes was determined from 4-day food records. On Day 4, participants provided a 24-hour urine collection. Urinary isoflavonoid (genistein, daidzein, equol, and O-desmethylangolensin) excretion was measured by gas chromatography-mass spectrometry. Twenty-one of the 60 participants (35%) excreted equol (> 2000 nmol/day) after 3 days of consuming the soy supplement. Daily equol excretion ranged from 2,134-20,301 nmol/day in the excreters and 21-233 nmol/day in the nonexcreters. There was no difference in equol excreter prevalence between men (43%) and women (27%). Daily excretion of daidzein, genistein, and O-desmethylangolensin was similar between equol excreters and nonexcreters and between men and women. Among the women, equol excreters consumed a significantly higher percentage of energy as carbohydrate and greater amounts of plant protein and dietary fiber, both as soluble and insoluble fiber compared to nonexcreters. Such differences were not observed in the men, who overall had significantly higher fiber intakes than the women. These data suggest that, among women, dietary fiber or other components of a high-fiber diet may promote the growth and/or the activity of bacterial populations responsible for equol production in the colon.

Urinary isoflavonoid excretion in humans is dose dependent at low to moderate levels of soy-protein consumption

Soybeans contain isoflavones, which have been associated with many health benefits, including decreased cancer risk. The purpose of our study was to measure urinary isoflavonoid excretion in response to daily consumption of soy that contained 0-36 mg isoflavones--a lower range than used in previous studies--and to compare urinary isoflavonoid excretion between equol excreters and nonexcreters. Fourteen men and women aged 20-40 y participated in the study. Half of the subjects were identified previously as equol excreters and the other half as equol nonexcreters. This randomized, double-blind, crossover study consisted of four 9-d diet treatment periods. During each treatment period participants consumed a low-photoestrogen controlled diet and a beverage containing 0, 5, 10, or 20 g soy protein. Urine collected on the last 3 d of each treatment period was analyzed for isoflavonoid (equol, O-desmethylangolensin, genistein, and daidzein) and lignan (enterodiol and enterolactone) contents by using isotope-dilution gas chromatography-mass spectrometry. There was a highly linear dose response of urinary isoflavonoid excretion to soy consumption, which did not differ significantly between equol excreters and nonexcreters. There were no significant differences in lignan excretion between the two diet treatments. Our results indicate that urinary isoflavonoid excretion is dose dependent in humans at low to moderate levels of soy consumption.

Molecular cloning and sequencing of a novel human P2 nucleotide receptor

A novel human P2 nucleotide receptor has been cloned from a T-cell cDNA library. The predicted amino acid sequence shows characteristics of a G-protein-coupled receptor, and shares 88% homology with a recently characterised rat P2 nucleotide receptor sequence. Distinctive features include an extremely short cytoplasmic tail with only one putative protein kinase C phosphorylation site. Northern blot analysis revealed a 1.9 kb transcript expressed in the placenta.

Attenuation of genetic hypertension after short-term vasopressin V1A receptor antagonism

Abnormalities of the vasopressin system are found in genetic hypertension. This study compares the delayed effects of a brief period of vasopressin V1A receptor blockade and angiotensin-converting enzyme inhibition in young female and male spontaneously hypertensive rats (SHR) on the development of hypertension in adult life. In a separate study, the role of vasopressin in the maintenance of blood pressure in adult SHR was assessed. Young SHR received either the nonpeptide vasopressin V1A receptor antagonist OPC-21268, the angiotensin-converting enzyme inhibitor ramipril, or vehicle from 6 to 10 weeks of age. During the treatment period, OPC-21268 and ramipril reduced systolic blood pressure compared with control SHR (P < .001). Blood pressure in male SHR 7 weeks after treatment withdrawal was 178 +/- 1 mm Hg in ramipril-treated, 184 +/- 1 mm Hg in OPC-21268-treated, and 200 +/- 2 mm Hg in control SHR (P < .001). Similar results were seen in female SHR, although both OPC-21268 and ramipril were less effective antihypertensive agents in female compared with male SHR. The sustained attenuation in blood pressure was not associated with significant cardiovascular structural changes (left ventricular-to-body weight ratio, renal weight-to-body weight ratio, mesenteric resistance artery media-to-lumen ratio). Results of vasopressin V1A receptor binding kinetics and plasma renin or aldosterone concentrations did not suggest a lasting effect of OPC-21268 on the vasopressin system or of ramipril on the renin-angiotensin system following treatment withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

Developmental changes in the expression patterns of IGFs, type 1 IGF receptor and IGF-binding proteins-2 and -4 in perinatal rat lung

The insulin-like growth factors (IGF-I and IGF-II), their receptors and binding proteins (IGFBPs) are endogenously expressed in a number of tissues including the lung during fetal and neonatal development. This endogenous autocrine/paracrine IGF 'system', together with endocrine sources, contributes to the regulation of lung cell proliferation. We investigated the expression of the mRNAs encoding IGF-I, IGF-II, the type 1 IGF receptor (IGF-T1R) and two IGF-binding proteins (IGFBP-2 and IGFBP-4) in rat lung during the perinatum. These were compared in lung with surfactant apoprotein A (Sp-A) mRNA levels. mRNA in extracts of fetal tissues collected between day 17 of gestation (17f) and day 9 after birth (9d) was estimated by Northern blot or RNase protection analysis. At day 20 of gestation IGF-I, IGF-T1R and IGFBP-4 mRNA levels were higher in lung than liver (all P < 0.01), whereas IGF-II and IGFBP-2 mRNA levels were higher in liver than lung (each P < 0.02). The expression of IGF-1, IGFBP-2 and IGFBP-4 in lung was high before birth (days 17-20f) but decreased to low levels at days 21f, 22f or at birth (1d) but increased in the neonatal lung. IGF-II expression in lung was high at 17f but decreased before birth and remained low after birth. The IGF-T1R was expressed at moderate levels before birth, decrease before birth but peaked at days 2-5 after birth. The decrease in expression of these growth regulators before birth expression of these growth regulators before birth was matched by an increased in Sp-A expression which was clearly seen at day 20f, peaked at 1d and then was clearly seen at day 20f, peaked at 1d and then was maintained at high levels after birth. Primary cell cultures of 18f lung epithelia express IGFBP-2 while fibroblasts from the same animals express only IGFBP-4. Cells grown from 22f lung tissue express IGFBP-2 and IGFBP-4 at lower levels, behaving in vitro as they do in vivo. The contrasting levels of expression of different components of the IGF system in the fetal lung and liver indicate organ-specific regulation. IGFBP-2 and IGFBP-4 expression in different cell types within lung but with similar temporal changes suggests cell-specific regulation, perhaps by a common agent. The patterns by a common agent. The patterns of expression of IGF-I, IGF-T1R, IGFBP-2 and IGFBP-4, but not IGF-II, in developing lung correspond to previously described phasic changes in lung cell proliferation rates. The nadir in expression of these four major components of the lung IGF system occurs in the saccular phase when the lung begins to differentiate, probably under the influence of certain endocrine agents.

Molecular cloning and sequencing of the gene encoding a sheep arginine vasopressin type 1a receptor

The gene for the sheep arginine vasopressin type 1a (V1a) receptor subtype was cloned from a genomic library. The deduced amino acid sequence shows characteristics of a G-protein coupled receptor and high sequence identity to human and rat V1a receptor sequences (81% and 73%, respectively). Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed a tissue distribution consistent with a type V1a receptor. The genomic DNA (7.1 kb) contains a 1586 bp intron between the putative 6th and 7th transmembrane domains.

Vegetables, fruits, and legumes: effect on urinary isoflavonoid phytoestrogen and lignan excretion

OBJECTIVE

To compare the effect of vegetable, fruit, and legume consumption on urinary isoflavonoid phytoestrogen and lignan excretion.

DESIGN

After 4 days of data collection, during which subjects consumed their habitual diets, subjects were randomly placed on four 9-day controlled experimental diets with each subject receiving each diet in a random order.

SUBJECTS

Seven men and three women, aged 20 to 35 years, were recruited from the University of Minnesota Twin Cities community.

INTERVENTIONS

All subjects consumed four experimental diets in an assigned random order: a controlled basal diet, a legume/allium diet (containing garbanzo beans, garlic, and onions), and diets low or high in vegetables and fruits (containing apples, pears, potatoes, and carrots).

MAIN OUTCOME MEASURES

Urine samples that were collected while subjects consumed their habitual diets and during the last 3 days of each feeding period were analyzed for isoflavonoid and lignan content using isotope dilution gas chromatography-mass spectrometry.

STATISTICAL ANALYSIS PERFORMED

The effect of vegetable and fruit intake on urinary isoflavonoid and lignan excretion was analyzed using the general linear model procedure. Post hoc comparisons were made using Duncan's multiple range test.

RESULTS

Subjects excreted more of the lignan enterodiol on the high vegetable/fruit diet compared with the basal and legume/allium diets (P = .03); more of the isoflavonoids O-desmethylangolensin (O-DMA), genistein, and sum of isoflavonoids on the legume/allium diet compared with the other controlled diets (P < .05); and more of the isoflavan equol on the basal and legume/allium diets compared with the high vegetable/fruit diet (P < .01). Subjects who excreted higher levels of equol on the basal and legume/allium diets also consumed more of the milk-based pudding provided as part of the controlled diets.

CONCLUSIONS

Urinary lignan and isoflavonoid excretion changed in response to alterations in vegetable, fruit, and legume intake under controlled dietary conditions.

Down-regulation of vasopressin V1a receptor mRNA in diabetes mellitus in the rat

1. To investigate the mechanism of hepatic V1a vasopressin receptor down-regulation in streptozotocin-induced diabetes mellitus in the rat, we measured hepatic V1a receptor mRNA by in situ hybridization histochemistry using oligonucleotide probes to the V1a receptor and Northern blotting. 2. Diabetes mellitus caused hyperglycaemia, hyperosmolality and increased plasma vasopressin concentrations (P < 0.01). Hepatocyte V1a receptor mRNA was reduced by 76% in diabetic rats (P < 0.01) and by 53% in insulin-treated diabetic rats (P < 0.01) versus control rats, in parallel with reduced V1a radioligand binding and vasopressin-stimulated inositol phosphates production. There was a similar decrease in hepatic V1a/18S mRNA density ratio in the diabetic and diabetic+insulin groups (both P < 0.05 versus control). 3. These findings suggest that altered V1a mRNA transcription is responsible for the reduced hepatic V1a receptor density in diabetes mellitus.

Urinary isoflavonoid phytoestrogen and lignan excretion after consumption of fermented and unfermented soy products

OBJECTIVE

To compare the effects of consumption of fermented and unfermented soy products on excretion of urinary isoflavonoid phytoestrogens and lignans in healthy men.

DESIGN

A randomized, crossover trial consisting of two 9-day feeding periods following 5 days of baseline data collection.

SUBJECTS

Healthy men, aged 20 to 40 years, were recruited from the University of Minnesota Twin Cities community. Of the 22 subjects who began the study, 17 completed all feeding periods.

INTERVENTIONS

Fermented soy product (112 g tempeh) or unfermented soy (125 g soybean pieces) was consumed during each controlled feeding period.

MAIN OUTCOME MEASURE

Urine samples collected while subjects consumed their habitual diets and on the last 3 days of each feeding period were analyzed for isoflavonoid and lignan content by isotope dilution gas chromatography-mass spectrometry.

STATISTICAL ANALYSIS PERFORMED

Comparisons of isoflavonoid and lignan excretion were analyzed using the general linear model procedure. Orthogonal contrasts were used to determine treatment differences of interest.

RESULTS

Urinary excretion of isoflavonoids (equol, O-desmethylangolensin [O-DMA], daidzein, genistein) was higher and excretion of lignans (enterodiol, enterolactone) was lower when subjects consumed soy-supplemented diets than when they consumed their habitual diets (P < .05). Urinary isoflavonoid excretion and lignan excretion were similar when subjects consumed tempeh and soybean pieces diets; however, recovery of daidzein and genistein was significantly higher when subjects consumed the tempeh diet than when they consumed the soybean pieces diet (P < .002). When fed soy, 5 of 17 subjects excreted high amounts of equol. These five subjects tended to excrete less O-DMA and daidzein than the 12 subjects who excreted low amounts of equol (P < .06).

CONCLUSIONS

Fermentation of soy decreased the isoflavone content of the product fed but increased the urinary isoflavonoid recovery. This finding suggests that fermentation increases availability of isoflavones in soy.

V1-like [Arg8]vasopressin binding sites occur in rat hepatocyte nuclei

Arginine vasopressin binding site characterisation was performed on purified nuclei and plasma membranes from livers of Sprague-Dawley rats. [125I][d(CH2)5,Sarc7,Arg8]vasopressin, a selective V1 vasopressin receptor antagonist radioligand, bound to the nuclei in a protein concentration and time dependent manner. Scatchard analysis of nuclear binding sites revealed a single binding site with maximal binding site density (Bmax) of 115 +/- 13 fmol/mg protein and affinity (KD) of 5.2 +/- 0.7 nM. Plasma membrane binding demonstrated a Bmax of 529 +/- 25 fmol/mg protein and KD of 1.9 +/- 0.1 nM. The displacement profile for nuclear binding sites using vasopressin analogues was similar to that for plasma membrane binding sites and was typical of a V1 vasopressin receptor type. There was no evidence of V2-like vasopressin receptor binding using [3H]des-Gly-NH9(2)[d(CH2)5,D-Ile2,Ile4,Arg8]vasopressi n, a selective V2 vasopressin receptor radioligand, in the nuclear or membrane fractions. These results suggest the existence of nuclear V1-like vasopressin binding sites.

Effects of anti-emetics on water excretion in humans

1. The anti-emetic drug metoclopramide has been shown to stimulate secretion of the antidiuretic hormone arginine vasopressin. Since metoclopramide is used to treat nausea, which is another potent stimulus to vasopressin secretion, the aim of this study was to determine whether metoclopramide might limit free water excretion and so cause hyponatraemia. 2. Metoclopramide 20 mg (0.2-0.3 mg/kg), prochlorperazine 12.5 mg (0.1-0.2 mg/kg) and placebo were administered intravenously in a double blind randomized crossover way at 2 week intervals and the effects on urine flow rate, plasma osmolality, thirst ratings and plasma sodium and atrial natriuretic peptide concentrations determined in water-loaded (10 mL/kg) healthy young men. 3. There were no differential effects on any variable of either drug versus placebo. 4. These results indicate that metoclopramide is unlikely to cause any significant water retention in a clinical setting or precipitate hyponatraemia.

Characterization of a novel non-peptide vasopressin V1 receptor antagonist (OPC-21268) in the rat

A non-peptide, orally effective, vasopressin (AVP) V1 receptor antagonist 1-(1-[4-(3-acetylaminopropoxy) benzoyl]-4-piperidyl)-3,4-dihydro-2(1H)-quinolinone (OPC-21268) has recently been described. This paper reports the in-vitro and in-vivo characterization of OPC-21268 binding to vasopressin receptors in rat liver and kidney. OPC-21268 caused a concentration-dependent displacement of the selective V1 receptor antagonist radioligand, 125I-labelled [d(CH2)5,sarcosine7]AVP to V1 receptors in both rat liver and kidney medulla membranes. The concentration of OPC-21268 that displaced 50% of specific AVP binding (IC50) was 40 +/- 3 nmol/l for liver V1 and 15 +/- 2 nmol/l for kidney V1 receptors (mean +/- S.E.M.; n = 3). OPC-21268 had little effect on the selective V2 antagonist radioligand [3H]desGly-NH2(9)]d(CH2)5,D-Ile2,Ile4] AVP binding to V2 receptors in renal medulla membranes (IC50 > 0.1 mmol/l). After oral administration to rats, OPC-21268 was an effective V1 antagonist in a time- and dose-dependent manner. Binding kinetic studies showed that OPC-21268 acted as a competitive antagonist at the liver V1 receptor in vitro and in vivo, in addition to its in-vitro competitive effects at the renal V1 receptor. OPC-21268 shows promise as an orally active V1 antagonist.

Effects of an orally active vasopressin V1 receptor antagonist

1. This paper reports on the in vitro and in vivo characteristics of a non-peptide vasopressin V1 receptor antagonist 1-(1-[4-(3-acetylaminopropoxy)benzoyl]-4-piperidyl)-3,4-dihydro-2( 1H)- quinolinone (OPC-21268). 2. OPC-21268 caused a concentration-dependent displacement of the selective V1 receptor antagonist radioligand, [125I]-[d(CH2)5, sarcosine7]AVP from vasopressin V1 receptors in rat liver and kidney membranes, inhibitory concentration of 50% (IC50) 4 x 10(-8), 0.3 mol/L liver and 1.5 x 10(-8), 0.2 mol/L kidney. OPC-21268 had little effect on the selective V2 antagonist radioligand [3H]desGly-NH2(9)-d(CH2)5[D-Ileu2, Ileu4]AVP binding to V2 receptors in renal membranes (IC50 > 10(-4) mol/L). 3. After oral administration to rats, OPC-21268 was an effective V1 antagonist to both liver and kidney V1 receptors, in a dose-dependent manner. 4. These studies confirm that OPC-21268 is a potent non-peptide, orally effective V1 vasopressin receptor antagonist.

Purification of olfactory nerve ensheathing cells from the olfactory bulb

Cells of the olfactory nerve layer of the olfactory bulb are labeled with the O4 antibody, which also labels Schwann cells, oligodendrocytes, and many oligodendrocyte-type-2 astrocyte (O-2A) progenitors. Purification of cells which were O4+, but did not express galactocerebroside (GC), from spinal cord, hippocampus, corpus callosum, and cerebellum of perinatal rats always yielded cells with the expected characteristics of O-2A progenitors. In contrast, the great majority of O4+GC- cells isolated from the olfactory bulb expressed an antigenic phenotype and pattern of differentiation in vitro which did not correspond with that of any previously described glial populations. As the localization of O4 staining in the olfactory bulb indicates that these cells are olfactory nerve ensheathing cells (ONECs), our results therefore suggest that ONECs represent a novel glial cell-type which can now be analyzed as a purified population.

IGF binding protein-2 gene expression and the location of IGF-I and IGF-II in fetal rat lung

Binding proteins for the insulin-like growth factors (IGF-BPs) are important modulators of the biological actions of IGF-I and IGF-II. The generation of IGFBPs within developing organs, and their spatial arrangement, may similarly determine IGF action at specific microanatomical sites. In situ hybridization studies with late gestation (days 16, 18 and 20) fetal rat lung using a cDNA probe for IGFBP-2 showed strong gene expression in the fetal lung epithelial structures (alveoli and airways). The sites of IGFBP-2 gene expression were associated with immunoreactive IGF-II at the apical surface of the epithelium. By day 20, there was also some IGFBP-2 gene expression and immunoreactive IGF-II at discrete sites in the mesenchyme. In contrast, immunoreactive IGF-I was found predominantly distributed in a punctate pattern, consistent with its presence in the lumen or walls of small vessels or capillaries, and in a granular, intracellular form in both epithelial and mesenchymal cells. These studies suggest that endogenously generated IGFBP-2 may determine the distribution of IGF-II, principally at the apical surface of lung epithelia. IGF-I does not colocalise with IGF-II peptide or the sites of IGFBP-2 gene expression. We conclude that the spatial distributions of these two related growth factors are separately controlled, to some extent by endogenously generated binding proteins.

Relationship between sensitivity to 4'-(9-acridinylamino)methanesulfon-m-anisidide and DNA topoisomerase II in a cold-sensitive cell-cycle mutant of a murine mastocytoma cell line

The cold-sensitive (proliferating at 39.5 degrees C, reversibly arrested in GI-phase at 33 degrees C) cell-cycle mutant 21-Fb of the murine mastocytoma cell line P815 was used to study the effect of amsacrine on non-cycling cells. The sensitivity of arrested 21-Fb cells decreased less than 2-fold in cell survival experiments when compared to proliferating cells. In contrast, DNA breakage and stimulation of protein-DNA complex formation in intact or lysed cells was reduced approx. 10-fold in arrested cells and DNA topoisomerase II activity in arrested cells was only 5% of the activity in proliferating cells. Thus, there was no correlation between cell survival and DNA damage or DNA topoisomerase II activity in drug-treated cells.