Jagged 2 silencing inhibits motility and invasiveness of colorectal cancer cell lines.

Although the Notch pathway has been reported to be activated in colorectal cancer (CRC), limited information is available regarding the expression and role of its ligand, Jagged 2 (JAG2), in CRC. Using immunohistochemistry, the present study demonstrated that JAG2 protein expression may be detected in up to 95% of CRC cases and is 3-fold upregulated in tumor cells compared to surrounding normal tissues. This finding suggests that JAG2 may have a role in the tumorigenicity of CRC. To further investigate the cellular functions of JAG2 expression in CRC, two different small interfering RNAs (siRNAs) were used to downregulate JAG2 expression in CRC cell lines (HCT116, DLD-1 and HT-29). The results indicated that JAG2 knockdown inhibits the motility and invasiveness of CRC cell lines without significantly affecting cell proliferation. These findings implicate JAG2 in promoting aggressiveness of CRC, and lay the foundation for its future development as a therapeutic target for the treatment of CRC.

Advanced technologies for studying circulating tumor cells at the protein level.

Metastasis is the main cause of cancer death. As the tumor progresses, cells from the primary tumor site are shed into the bloodstream as circulating tumor cells (CTCs). Eventually, these cells colonize other organs and form distant metastases. It is therefore imperative that we gain a better understanding of the biological characteristics of CTCs for development of novel treatment modalities to minimize metastasis-associated cancer deaths. In recent years, rapid developments in technologies for the study of CTCs have taken place. We now have a variety of tools for the isolation and examination of CTCs which were not available before. This review introduces some commonly used protein markers in CTC investigations and summarizes a few advanced technologies which have been successfully applied for studying CTC biology at the protein level.

Covariation of major and minor viral capsid proteins in norovirus genogroup II genotype 4 strains.

We report sequence hypervariability in the viral protein 1 (VP1) interaction domain of VP2 in the norovirus (NoV) genogroup II genotype 4 (GII.4) lineage on 3 levels: (i) the global evolution of pandemic/epidemic strains from the mid-1970s through post-2006, (ii) the local emergence of an epidemic strain, and (iii) an immunocompromised patient chronically shedding NoV. When a quantitative yeast two-hybrid assay was used, VP2 was found to interact with VP1 in a time-ordered, strain-dependent manner among 3 NoV GII.4 strains. Our findings suggest that VP1 and VP2 may covary in virus evolution and that sequence hypervariability of VP2 may be functionally driven. Further investigations are warranted.

Seasonal influenza A virus in feces of hospitalized adults.

In a cohort of hospitalized adults with seasonal influenza A in Hong Kong, viral RNA was frequently (47%) detected in stool specimens. Viable virus was rarely isolated. Viral RNA positivity had little correlation with gastrointestinal symptoms and outcomes. In vitro studies suggested low potential for seasonal influenza viruses to cause direct intestinal infections.

In vitro whole-virus binding of a norovirus genogroup II genotype 4 strain to cells of the lamina propria and Brunner's glands in the human duodenum.

Human norovirus (hNoV) remains refractory to propagation in cell culture systems. We believe that knowing the exact cell type that hNoV targets will provide important insights into culturing the virus. By the use of an in vitro whole-virus binding assay, the hNoV genogroup II genotype 4 Sakai variant was found to bind predominantly to cells of the lamina propria and Brunner's glands, but not to those of the luminal epithelial surface, of human duodenum tissue. Our findings, together with accumulating evidence reported elsewhere, suggest that hNoV may display tropism to nonepithelial cells, which is distinct from observations of other human enteric pathogens.

Narcissus tazetta lectin shows strong inhibitory effects against respiratory syncytial virus, influenza A (H1N1, H3N2, H5N1) and B viruses.

A mannose-binding lectin (Narcissus tazetta lectin [NTL]) with potent antiviral activity was isolated and purified from the bulbs of the Chinese daffodil Narcissus tazetta var. chinensis, using ion exchange chromatography on diethylaminoethyl (DEAE)-cellulose, affinity chromatography on mannose-agarose and fast protein liquid chromatography (FPLC)-gel filtration on Superose 12. The purified lectin was shown to have an apparent molecular mass of 26 kDa by gel filtration and 13 kDa by SDS-PAGE, indicating that it is probably a dimer with two identical subunits. The cDNA-derived amino acid sequence of NTL as determined by molecular cloning also reveals that NTL protein contains a mature polypeptide consisting of 105 amino acids and a C-terminal peptide extension. Three-dimensional modelling study demonstrated that the NTL primary polypeptide contains three subdomains, each with a conserved mannose-binding site. It shows a high homology of about 60%-80% similarity with the existing monocot mannose-binding lectins. NTL could significantly inhibit plaque formation by the human respiratory syncytial virus (RSV) with an IC50 of 2.30 microg/ml and exhibit strong antiviral properties against influenza A (H1N1, H3N2, H5N1) and influenza B viruses with IC50 values ranging from 0.20 microg/ml to 1.33 microg/ml in a dose-dependent manner. It is worth noting that the modes of antiviral action of NTL against RSV and influenza A virus are significantly different. NTL is effective in the inhibition of RSV during the whole viral infection cycle, but the antiviral activity of NTL is mainly expressed at the early stage of the viral cycle of influenza A (H1N1) virus. NTL with a high selective index (SI=CC50/IC50 > or = 141) resulting from its potent antiviral activity and low cytotoxicity demonstrates a potential for biotechnological development as an antiviral agent.

Antiviral activity of daphnoretin isolated from Wikstroemia indica.

The ethanol extract of Wikstroemia indica was fractionated with organic solvents of different polarities, and various fractions were screened for their antiviral activity against respiratory syncytial virus (RSV) using a cytopathic effect (CPE) reduction assay. The ethyl acetate fraction was most active against RSV with 50% inhibition concentration (IC(50)) value < 3.9 microg/mL and a selectivity index (SI) > 64.1. Further isolation and purification of the fraction led to a purified compound, daphnoretin. Daphnoretin was tested for its anti-RSV activity using a plaque reduction assay and found active against RSV, with an IC(50 )value of 5.87 microg/mL and SI value of 28.17. The mode of antiviral action study revealed that daphnoretin could slightly inhibit the early events of the viral infection but its effect was mainly on the later phase of the replication cycle.

Isolation, characterization, molecular cloning and modeling of a new lipid transfer protein with antiviral and antiproliferative activities from Narcissus tazetta.

A fetuin-binding peptide with a molecular mass of about 9kDa (designated NTP) was isolated and purified from the bulbs of Chinese daffodil, Narcissus tazetta var. chinensis L., by gel filtration and high-performance liquid chromatography, after removing the mannose-binding proteins by mannose-agarose column. Molecular cloning revealed that NTP contained an open reading frame of 354bp encoding a polypeptide of 118 amino acids which included a 26-amino-acid signal peptide. An analysis of the deduced amino acid sequence of NTP shows considerable sequence homology to the non-specific lipid transfer proteins (nsLTPs) of certain plants. Model of the three-dimensional (3D) structure of NTP exhibits an internal hydrophobic cavity which can bind lipid-like molecules and transfer a wide range of ligands. As a member of the putative non-specific lipid transfer protein of N. tazetta, NTP did not possess hemagglutinating activity toward rabbit erythrocytes. In a cell-free system, it could arrest the protein synthesis of rabbit reticulocytes. Using the in vitro antiviral assays, NTP could significantly inhibit the plaque formation by respiratory syncytial virus (RSV) and the cytopathic effect induced by influenza A (H1N1) virus, as well as the proliferation of human acute promyelocytic leukemia cells (HL-60).