Human TRIB2 is a repressor of FOXO that contributes to the malignant phenotype of melanoma cells

FOXO transcription factors are evolutionarily conserved proteins that orchestrate gene expression programs known to control a variety of cellular processes such as cell cycle, apoptosis, DNA repair and protection from oxidative stress. As the abrogation of FOXO function is a key feature of many tumor cells, regulation of FOXO factors is receiving increasing attention in cancer research. In order to discover genes involved in the regulation of FOXO activity, we performed a large-scale RNA-mediated interference (RNAi) screen using cell-based reporter systems that monitor transcriptional activity and subcellular localization of FOXO. We identified genes previously implicated in phosphoinositide 3-kinase/Akt signaling events, which are known to be important for FOXO function. In addition, we discovered a previously unrecognized FOXO-repressor function of TRIB2, the mammalian homolog of the Drosophila gene tribbles. A cancer-profiling array revealed specific overexpression of TRIB2 in malignant melanoma, but not in other types of skin cancer. We provide experimental evidence that TRIB2 transcript levels correlate with the degree of cytoplasmic localization of FOXO3a. Moreover, we show that TRIB2 is important in the maintenance of the oncogenic properties of melanoma cells, as its silencing reduces cell proliferation, colony formation and wound healing. Tumor growth was also substantially reduced upon RNAi-mediated TRIB2 knockdown in an in vivo melanoma xenograft model. Our studies suggest that TRIB2 provides the melanoma cells with growth and survival advantages through the abrogation of FOXO function. Altogether, our results show the potential of large-scale cell-based RNAi screens to identify promising diagnostic markers and therapeutic targets.

Modifications in host cell cytoskeleton structure and function mediated by intracellular HIV-1 Tat protein are greatly dependent on the second coding exon

The human immunodeficiency virus type 1 (HIV-1) regulator Tat is essential for viral replication because it achieves complete elongation of viral transcripts. Tat can be released to the extracellular space and taken up by adjacent cells, exerting profound cytoskeleton rearrangements that lead to apoptosis. In contrast, intracellular Tat has been described as protector from apoptosis. Tat gene is composed by two coding exons that yield a protein of 101 amino acids (aa). First exon (1–72aa) is sufficient for viral transcript elongation and second exon (73–101 aa) appears to contribute to non-transcriptional functions. We observed that Jurkat cells stably expressing intracellular Tat101 showed gene expression deregulation 4-fold higher than cells expressing Tat72. Functional experiments were performed to evaluate the effect of this deregulation. First, NF-κB-, NF-AT- and Sp1-dependent transcriptional activities were greatly enhanced in Jurkat-Tat101, whereas Tat72 induced milder but efficient activation. Second, cytoskeleton-related functions as cell morphology, proliferation, chemotaxis, polarization and actin polymerization were deeply altered in Jurkat-Tat101, but not in Jurkat-Tat72. Finally, expression of several cell surface receptors was dramatically impaired by intracellular Tat101 but not by Tat72. Consequently, these modifications were greatly dependent on Tat second exon and they could be related to the anergy observed in HIV-1-infected T cells.

Effect of progesterone administration on the ovarian response to superovulatory treatments in cattle

To evaluate ovarian response in Angus cows previously treated with progesterone (P4), animals were randomly assigned to two groups: T600 group (n=14), 600 mg of P4/day. P4 was injected from days 3 to 7 of the estrous cycle. On day 7, superovulatory treatments began. The control group (n=12) was given vehicle only. The superovulatory treatments in the control group began on days 7-9 of the estrous cycle. The superovulatory total treatment dose of 400mg NIH FSH P1 was given twice a day over a 4-day period. Ultrasonography of the ovaries was conducted 3 days preceding the initiation of superovulatory treatment, every 24h. In both groups, an additional ultrasonographic evaluation was made at 24h after the end of superovulatory treatment. Blood samples were collected 4 days preceding the initiation of superovulatory treatment, every 24h. Additional samples were taken from the P600 group for 12 day after of initiation of superovulatory treatment every 24h, except on the fifth day after the initiation of superovulatory treatment. In the P600 group, P4 concentrations were greater than in the control group (P<0.01) and remained over 1 ng/ml up to day 11 after beginning of superovulatory treatment. The diameter of the dominant follicle was larger in the animals of the control group (P<0.01). Cows of the P600 group had a greater number of Class I (3-4mm) follicles (P<0.01). A significant day and treatment effect (P<0.01) were observed in Class II (5-9 mm) follicles. Effects due to treatment on the number of Class III follicles (P<0.05) were observed. In the P600 group, no estrous post-superovulatory was observed and there were no ovulations that occurred. Conversely, 100% of the cows of the control group showed estrous. In the P600 group, there were a greater number of Class III follicles (P<0.01) and a lesser number of Class II follicles (P<0.05) at 24h after the end of superovulatory. In the control group, 66.7% of the cows responded to superovulatory treatments. In conclusion, the daily administration of 600 mg of P4, from days 3 to 7 of the estrous cycle, produces an increase of plasma concentrations of this hormone from day 4, resulting in changes in follicular dynamics (absence of follicles greater than 10mm of diameter and an increase of the population of Class I follicles). As to the ovarian stimulation using Folltropin V in animals receiving a daily injection of 600 mg of P4 from days 3 to 7 of the estrous cycle, a greater population of follicles>or=10mm developed by 24h after superovulatory treatments were completed.

Bioavailability of fluticasone propionate and mometasone furoate aqueous nasal sprays

OBJECTIVES

To compare the systemic exposure for intranasal mometasone furoate (MF) and fluticasone propionate (FP) aqueous nasal sprays (ANS) in terms of serum and urinary cortisol parameters and plasma pharmacokinetics.

METHODS

Twelve healthy subjects completed this three-way, cross-over study. They received FPANS (50 microg/spray), MFANS (50 microg/spray) or placebo ANS, eight sprays per nostril every 8 h for 4 days. Cortisol measurements were made at baseline and day 4. FP and MF plasma concentrations were also measured on day 4.

RESULTS

MFANS produced similar mean plasma AUC (123 pmol/l h) to FPANS (112 pmol/l h). Despite the use of high doses, necessary to generate adequate pharmacokinetic data, only minor reductions in cortisol parameters were found, with no difference between FPANS and MFANS.

CONCLUSIONS

FP and MF have similar and very low systemic bioavailability when administered intranasally using a high-dose regimen. It is therefore unlikely that therapeutic doses of intranasal FP or MF will produce dissimilar or significant degrees of systemic exposure or systemic effects.

Ciliate cryptobiosis: a microbial strategy against environmental starvation

This review outlines the main features of ciliate resting-cyst formation or encystment. It represents a strategy against several environmental stresses (such as starvation), which involves a highly gene-regulated cell differentiation process and originates a more resistant, differentiated form or resting cyst. This process is mainly characterized by drastic cytoplasmic dehydration that induces a general metabolic rate decrease, intense autophagic activity, the formation of a permeable cyst wall protecting the cell against the adverse environmental conditions, and a gene-silencing mechanism after opening the specific encystment genes.

DNA methylation in ciliates: implications in differentiation processes

Much experimental evidence on the role of DNA methylation in gene expression has been reported. Here we review reports on DNA methylation in ciliated protozoa, emphasizing its implications in cell differentiation processes. Both types of methylated bases (adenine and cytosine) can be found in macronuclear DNA. The division cycle and conjugation have been studied with regard to adenine methylation, and several different functions have been assigned to the methylation changes detected in these processes. Cytosine methylation changes were analyzed during stomatogenesis of Paramecium and encystment of Colpoda inflata. A comparative analysis with other similar microbial eukaryotic differentiation processes is carried out.

From hydrofluoroalkane pressurized metered dose inhalers (pMDIs) and comparability with chlorofluorocarbon pMDIs

Fluticasone propionate pressurized metered dose inhalers (pMDIs) containing the hydrofluoroalkane (HFA) propellant, HFA 134a, are being developed to replace existing chlorofluorocarbon (CFC) pMDIs. This is part of the ongoing worldwide project to limit the damage to the earth's ozone layer. The in vivo performance and dose proportionality of fluticasone propionate HFA 134a pMDIs was examined for fluticasone propionate doses of 400, 1000 and 2000 microg using the 50, 125 and 250 microg strength pMDIs, respectively. The 125 and 250 microg strength HFA 134a pMDIs were compared with corresponding fluticasone propionate CFC pMDIs. Twenty-three healthy subjects participated in this single dose, randomized, five-way, cross-over study. Serial blood samples were collected 24 h post-dose to measure fluticasone propionate plasma concentrations. Twenty-four hour urinary-free cortisol was also measured before and after dosing. A dose-proportional increase in plasma fluticasone propionate concentrations was observed with increasing dose for the HFA 134a pMDIs. This was associated with a dose-related decrease in urinary cortisol excretion. Similar or lower fluticasone propionate systemic exposure was observed with the HFA 134a pMDIs compared to the corresponding CFC inhalers. The differences in systemic exposure observed for the HFA 134a and CFC pMDIs were too small to produce a differential effect on urinary cortisol excretion. Since fluticasone propionate has negligible oral bioavailability, the systemic exposure, which arises only from pulmonary absorption, is a measure of lung deposition. There was a good correlation between the in vitro fine particle mass produced by the different strengths and types of pMDI and the systemic exposure to fluticasone propionate. Therefore, the fluticasone propionate HFA 134a pMDI is an acceptable pharmaceutical alternative to the current CFC pMDI, producing similar lung deposition and no increase in systemic exposure at microgram equivalent doses.

Anatomicohistological characteristics of the ovary of the coypu (Myocastor coypus)

Using histological, histochemical and macroscopic and microscopic measurement techniques, the macroscopic and microscopic structures of coypu ovaries were studied in sexually mature virgin females. The mature ovaries of the coypu were ovoid or elongated bodies, not encapsulated, covered by a single layer of epithelium. They had a parenchyma formed by follicles at different stages of evolution and true and accessory corpora lutea. The interstitial tissue was a prominent and permanent structure in the ovaries. Some ovaries contained a few rete ovarii in the hilus.

Anatomicohistological characteristics of female genital tubular organs of the South American nutria (Myocastor coypus)

Morphohistological features of the tubular organs of the Myocastor coypus (coypu) female reproductive tract were studied. Specimens came from breeding farms with yard breeding systems. The analysis of the organs was made by histological methods and by macro and microscopic measurement techniques. The animals showed oviducts with macro and microscopically differentiable regions. Their inucosa showed primary branched folds in the ampullar sector. In the rest of the oviduct tract these folds were only of the primary type. The double uterus showed regional variations in the lumen, endometrial glands along the whole surface and a wide fibromuscular cervix with pseudoglands. The endocervical mucosa made clear a complex system of folds covered by a mucus-secreting epithelium. In the long vagina of the coypu a folded, rugose and irregular mucosa was observed.

Lectin-binding sites in uterus and oviduct of normal and Campylobacter fetus subspecies venerealis-infected heifers

This study was carried out to investigate the effect of infection with Campylobacter fetus subsp. venerealis (Cfv) on the pattern of lectin binding in the uterus and oviduct of heifers. Cfv persistence was demonstrated by bacterial isolation and immunofluorescence. Infected animals showed variations in the lectin binding pattern when compared with control animals. Cfv-infected heifers showed an increased expression of galactose and N-acetyl-galactosamine in the endometrial glands (PNA and SBA binding, respectively). The oviductal epithelium of infected heifers was strongly positive for Con A, which indicated the presence of alpha-D-mannose and alpha-D-glucose. The results of this study showed that Cfv-infection modifies the lectin binding pattern in the reproductive system of heifers. Modifications in glycoconjugates may be involved in failures of fertility and/or implantation.

The pattern of zygotene and pachytene pairing in allotetraploid Aegilops species sharing the D genome

Chromosome pairing behaviour of the allotetraploid Aegilops species sharing the D genome, Ae. crassa (DDMM), Ae. cylindrica (DDCC) and Ae. ventricosa (DDNN), was analyzed by electron microscopy in surfacespread prophase-I nuclei. Synaptonemal-complex analysis at zygotene and pachytene revealed that synapsis in the allotetraploids was mostly between homologous chromosomes, although a few multivalents were also formed. Only homologous bivalents were observed at metaphase-I. It is concluded that the mechanism controlling bivalent formation in these species acts mainly at zygotene by restricting pairing to homologous chromosomes, but also acts at pachytene by preventing chiasma formation in homoeologous associations. These observations are discussed in relation to mechanisms of diploidization of polyploid meiosis.

The pattern of zygotene and pachytene pairing in allotetraploid Aegilops species sharing the U genome

Allotetraploid Aegilops species sharing the U genome, Ae. columnaris (UUMM), Ae. ovata (UUMM), Ae. triaristata (UUMM), Ae. triuncialis (UUCC) and Ae. variabilis (UUSS), regularly form bivalents at metaphase I of meiosis. The pattern of zygotene and pachytene pairing was analyzed by whole-mount surface-spreading of synaptonemal complexes under the electron microscope. The data indicated that at the zygotene stage the chromosomes were almost exclusively associated as bivalents; only a few multivalents (7%) were observed. These observations are discussed in relation to mechanisms of diploidization of polyploid meiosis.

Chromosome pairing in the allotetraploid Aegilops biuncialis and a triploid intergeneric hybrid

Chromosome pairing behaviour of the natural allotetraploid Aegilops biuncialis (genome UUMM) and a triploid hybrid Ae. biuncialis × Secale cereale (genome UMR) was analyzed by electron microscopy in surface-spread prophase I nuclei. Synaptonemal-complex analysis at zygotene and pachytene revealed that synapsis in the allotetraploid was mostly between homologous chromosomes, although a few quadrivalents were also formed. Only homologous bivalents were observed at metaphase I. In contrast, homoeologous and heterologous chromosome associations were common at prophase I and metaphase I of the triploid hybrid. It is concluded that the mechanism controlling bivalent formation in Ae. biuncialis acts mainly at zygotene by restricting pairing to homologous chromosomes, but also acts at pachytene by preventing chiasma formation in the homoeologous associations. In the hybrid the mechanism fails at both stages. Key words : Aegilops biuncialis, allotetraploid, intergeneric hybrid, pairing control, synaptonemal complex.

Molecular modification of anticholinergics as probes for muscarinic receptors. 1. Amino esters of alpha-substituted phenylacetic acid and related analogues

Two series of compounds having the general structure of C6H5CRR'COOCH2CH2NEt2 were synthesized and examined for their antispasmodic activities. These compounds were selected as structural probes for exploring the nature of muscarinic cholinergic receptor binding sites that interact with atropine-like anticholinergics. These studies indicate a rather strict size limitation for the hydrophobic region of the receptor and suggest intramolecular hydrogen bonding as a possible means to explain the observed stereoselectivity.