Downregulation of p57kip2 promotes cell invasion via LIMK/cofilin pathway in human nasopharyngeal carcinoma cells

The members of Rho family are well known for their regulation of actin cytoskeleton to control cell migration. The Cip/kip members of cyclin‐dependent (CDK) inhibitors have shown to implicate in cell migration and cytoskeletal dynamics. p57^kip2, a CDK inhibitor, is frequently down‐regulated in several malignancy tumors. However, its biological roles in human nasopharyngeal carcinoma (NPC) cells remained to be investigated. Here, we found p57^kip2 has nuclear and cytoplasm distributions and depletion of endogenous p57^kip2 did not change the cell‐cycle progression. Inhibition of cell proliferation by mitomycin C promoted FBS‐mediated cell migration and accompanied with the downregulation of ΔNp63α and p57^kip2, but did not change the level of p27^kip1, another CDK inhibitor. By using siRNA transfection and cell migration/invasion assays, we found that knockdown of p57^kip2, but not ΔNp63α, involved in promotion of NPC cell migration and invasion via decrease of phospho‐cofilin (p‐cofilin). Treatment with Y‐27632, a specific ROCK inhibitor, we found that dysregulation of ROCK/cofilin pathway decreased p‐cofilin expression and induced cell migration. This change of p‐cofilin induced actin remodeling and pronounced increase of membrane protrusions. Further, silence of p57^kip2 not only decreased the interaction between p57^kip2 and LIMK‐1 assayed by immunoprecipitation but also reduced the level of phospho‐LIMK1/2. Therefore, this study indicated that dysregulation of p57^kip2 promoted cell migration and invasion through modulation of LIMK/cofilin signaling and suggested this induction of inappropriate cell motility might contribute to promoting tumor cell for metastasis. J. Cell. Biochem. 112: 3459–3468, 2011. © 2011 Wiley Periodicals, Inc.     

High Resolution Size Analysis of Fetal DNA in the Urine of Pregnant Women by Paired-End Massively Parallel Sequencing

Background

Fetal DNA in maternal urine, if present, would be a valuable source of fetal genetic material for noninvasive prenatal diagnosis. However, the existence of fetal DNA in maternal urine has remained controversial. The issue is due to the lack of appropriate technology to robustly detect the potentially highly degraded fetal DNA in maternal urine.

Methodology

We have used massively parallel paired-end sequencing to investigate cell-free DNA molecules in maternal urine. Catheterized urine samples were collected from seven pregnant women during the third trimester of pregnancies. We detected fetal DNA by identifying sequenced reads that contained fetal-specific alleles of the single nucleotide polymorphisms. The sizes of individual urinary DNA fragments were deduced from the alignment positions of the paired reads. We measured the fractional fetal DNA concentration as well as the size distributions of fetal and maternal DNA in maternal urine.

Principal Findings

Cell-free fetal DNA was detected in five of the seven maternal urine samples, with the fractional fetal DNA concentrations ranged from 1.92% to 4.73%. Fetal DNA became undetectable in maternal urine after delivery. The total urinary cell-free DNA molecules were less intact when compared with plasma DNA. Urinary fetal DNA fragments were very short, and the most dominant fetal sequences were between 29 bp and 45 bp in length.

Conclusions

With the use of massively parallel sequencing, we have confirmed the existence of transrenal fetal DNA in maternal urine, and have shown that urinary fetal DNA was heavily degraded.     

Genetic isolation between the Western and Eastern Pacific populations of pronghorn spiny lobster Panulirus penicillatus

The pronghorn spiny lobster, Panulirus penicillatus, is a circumtropical species which has the widest global distribution among all the species of spiny lobster, ranging throughout the entire Indo-Pacific region. Partial nucleotide sequences of mitochondrial DNA COI (1,142-1,207 bp) and 16S rDNA (535-546 bp) regions were determined for adult and phyllosoma larval samples collected from the Eastern Pacific (EP)(Galápagos Islands and its adjacent water), Central Pacific (CP)(Hawaii and Tuamotu) and the Western Pacific (WP)(Japan, Indonesia, Fiji, New Caledonia and Australia). Phylogenetic analyses revealed two distinct large clades corresponding to the geographic origin of samples (EP and CP+WP). No haplotype was shared between the two regional samples, and average nucleotide sequence divergence (Kimura's two parameter distance) between EP and CP+WP samples was 3.8±0.5% for COI and 1.0±0.4% for 16S rDNA, both of which were much larger than those within samples. The present results indicate that the Pacific population of the pronghorn spiny lobster is subdivided into two distinct populations (Eastern Pacific and Central to Western Pacific), with no gene flow between them. Although the pronghorn spiny lobster have long-lived teleplanic larvae, the vast expanse of Pacific Ocean with no islands and no shallow substrate which is known as the East Pacific Barrier appears to have isolated these two populations for a long time (c.a. 1MY).     

Recognition of G-U mismatches by tris(4,7-diphenyl-1,10-phenanthroline)rhodium(III).

The coordination complex tris(4,7-diphenyl-1,10-phenanthroline)rhodium(III) [Rh(DIP)3(3+)], which promotes RNA cleavage upon photoactivation, has been shown to target specifically guanine-uracil (G-U) mismatches in double-helical regions of folded RNAs. Photoactivated cleavage by Rh(DIP)3(3+) has been examined on a series of RNAs that contain G-U mismatches, yeast tRNA(Phe) and yeast tRNA(Asp), as well as on 5S rRNAs from Xenopus oocytes and Escherichia coli. In addition, a "microhelix" was synthesized, which consists of seven base pairs of the acceptor stem of yeast tRNA(Phe) connected by a six-nucleotide loop and contains a mismatch involving residues G4 and U69. A U4.G69 variant of this sequence was also constructed, and cleavage by Rh(DIP)3(3+) was examined. In each of these cases, specific cleavage is observed at the residue which lies to the 3'-side of the wobble-paired U; some cleavage by the rhodium complex is also evident in several structured RNA loops. The remarkable site selectivity for G-U mismatches within double-helical regions is attributed to shape-selective binding by the rhodium complex. This binding furthermore depends upon the orientation of the G-U mismatch, which produces different stacking interactions between the G-U base pair with the Watson-Crick base pair following it on the 5'-side of U compared to the Watson-Crick pair preceding it on the 3'-side of U. Rh(DIP)3(3+) therefore serves as a unique probe of G-U mismatches and may be useful both as a model and in probing RNA-protein interactions as well as in identifying G-U mismatches within double-helical regions of folded RNAs.     

Poliovirus-specific major histocompatibility complex class I-restricted cytolytic T-cell epitopes in mice localize to neutralizing antigenic regions.

A major histocompatibility complex (MHC) class I-restricted cytotoxic T-lymphocyte (CTL) response is induced in BALB/c mice upon immunization with poliovirus serotype 1 (Mahoney strain). A similar class I-restricted response is also induced upon immunization with purified VP1 capsid proteins. Thus, poliovirus-specific MHC class I CTL responses can be induced independently of viral infection in murine hosts. In experiments using recombinant vaccinia virus vectors expressing different segments of the poliovirus capsid proteins and synthetic peptides, two regions of the VP1 capsid protein appear to contain epitopes recognized by this bulk CTL population. These epitope regions contain a Kd-restricted peptide-binding motif. Interestingly, each of these CTL epitopes is located near previously defined neutralizing antigenic sites.     

A syndromic approach to common parasitic diseases

Standard textbooks discuss parasitic disease according to specific organisms. In contrast, patients with parasitic infections present to physicians with a variety of clinical manifestations that may involve any of several organ systems and that often mimic nonparasitic diseases. A syndromic approach to the clinical situation may help the physician in considering the most important parasitic agents. Many parasitic infections can be acquired in temperate climates. While often considered tropical or exotic, other parasitic diseases are now seen more frequently in developed countries because of immigration and increased world travel. In this review the clinical syndromes associated with common parasitic diseases in North America are discussed, with an emphasis on risk factors and diagnosis of specific infections.     

Mold allergen, pen C 13, induces IL-8 expression in human airway epithelial cells by activating protease-activated receptor 1 and 2

Allergenic serine proteases are important in the pathogenesis of asthma. One of these, Pen c 13, is the immunodominant allergen produced by Penicillium citrinum. Many serine proteases induce cytokine expression, but whether Pen c 13 does so in human respiratory epithelial cells is not known. In this study, we investigated whether Pen c 13 caused IL-8 release and activated protease-activated receptors (PARs) in airway epithelial cells. In airway-derived A549 cells and normal human airway epithelial cells, Pen c 13 induced IL-8 release in a dose-dependent manner. Pen c 13 also increased IL-8 release in a time-dependent manner in A549 cells. Pen c 13 cleaved PAR-1 and PAR-2 at their activation sites. Treatment with Pen c 13 induced intracellular Ca(2+) mobilization and desensitized the cells to the action of other proteases and PAR-1 and PAR-2 agonists. Moreover, Pen c 13-mediated IL-8 release was significantly decreased in Ca(2+)-free medium and was abolished by the protease inhibitors, PMSF and 4-(2-aminoethyl) benzenesulfonyl fluoride. Blocking Abs against the cleavage sites of PAR-1 and PAR-2, but not of PAR-4, inhibited Pen c 13-induced IL-8 production, as did inhibition of phospholipase C. Pen c 13 induced IL-8 expression via activation of ERK 1/2, and not of p38 and JNK. In addition, treatment of A549 cells or normal human airway epithelial cells with Pen c 13 increased phosphorylation of ERK 1/2 by a Ca(2+)-dependent pathway. These finding show that Pen c 13 induces IL-8 release in airway epithelial cells and that this is dependent on PAR-1 and PAR-2 activation and intracellular calcium.     

Automation, parallelism, and robotics for proteomics

The speed of the human genome project (Lander, E. S., Linton, L. M., Birren, B., Nusbaum, C. et al., Nature 2001, 409, 860-921) was made possible, in part, by developments in automation of sequencing technologies. Before these technologies, sequencing was a laborious, expensive, and personnel-intensive task. Similarly, automation and robotics are changing the field of proteomics today. Proteomics is defined as the effort to understand and characterize proteins in the categories of structure, function and interaction (Englbrecht, C. C., Facius, A., Comb. Chem. High Throughput Screen. 2005, 8, 705-715). As such, this field nicely lends itself to automation technologies since these methods often require large economies of scale in order to achieve cost and time-saving benefits. This article describes some of the technologies and methods being applied in proteomics in order to facilitate automation within the field as well as in linking proteomics-based information with other related research areas.     

Quantification of a cytochrome P450 3A4 substrate, buspirone, in human plasma by liquid chromatography-tandem mass spectrometry

A sensitive HPLC-tandem mass spectrometry method was developed for determination of buspirone levels in human plasma. After solid phase extraction and reversed phase HPLC separation, detection of buspirone and the internal standard (prazosin) was performed using eletrospray ionization and selected reaction monitoring in the positive ion mode. Linear calibration curves were established over a concentration range of 0.025-2.5 ng/ml when 0.5 ml aliquots of plasma were used. Satisfactory results of within-day precision (RSD of 1.9-7.7%) and accuracy (% difference of 0.5-6.6%) and between-day precision (RSD of 3.7-11.1%) and accuracy (% difference of 2.2-6.8%) were obtained. The assay has been successfully applied to the analysis of buspirone levels in more than 500 human plasma samples collected from a drug interaction study.     

Arrhythmia and sudden death associated with elevated cardiac chloride channel activity

The identification and analysis of several cationic ion channels and their associated genes have greatly improved our understanding of the molecular and cellular mechanisms of cardiac arrhythmia. Our objective in this study was to examine the involvement of anionic ion channels in cardiac arrhythmia. We used a transgenic mouse model to overexpress the human cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes a cAMP-regulated chloride channel. We used RNase protection and in situ hybridization assays to determine the level of CFTR expression, and radiotelemetry and in vivo electrophysiological study in combination with pharmacological intervention to analyse the cardiac function. Cardiac CFTR overexpression leads to stress-related sudden death in this model. In vivo intracardiac electrophysiological studies performed in anaesthetized mice showed no significant differences in baseline conduction parameters including atrial-His bundle (AH) or His bundle-ventricular (HV) conduction intervals, atrioventricular (AV) Wenckebach or 2:1 AV block cycle length and AV nodal functional refractory period. However, following isoproterenol administration, there was marked slowing of conduction parameters, including high-grade AV block in transgenic mice, with non-sustained ventricular tachycardia easily inducible using programmed stimulation or burst pacing. Our sudden death mouse model can be a valuable tool for investigation of the role of chloride channels in arrhythmogenesis and, potentially, for future evaluation of novel anti-arrhythmic therapeutic strategies and pharmacological agents.