Cancer cells secrete small membranous extracellular vesicles (EVs) into their microenvironment and circulation. Although their potential as cancer biomarkers has been promising, the identification and quantification of EVs in clinical samples remains challenging. Here we describe a sensitive and rapid analytical technique for profiling circulating EVs directly from blood samples of patients with colorectal cancer. EVs are captured by two types of antibodies and are detected by photosensitizer-beads, which enables us to detect cancer-derived EVs without a purification step. We also show that circulating EVs can be used for detection of colorectal cancer using the antigen CD147, which is embedded in cancer-linked EVs. This work describes a new liquid biopsy technique to sensitively detect disease-specific circulating EVs and provides perspectives in translational medicine from the standpoint of diagnosis and therapy.
We have carried out a large-scale identification and characterization of human genes that activate the NF-kappaB and MARK signaling pathways. We constructed full-length cDNA libraries using the oligo-capping method and prepared an arrayed cDNA pool consisting of 150 000 cDNAs randomly isolated from the libraries. For analysis of the NF-kappaB signaling pathway, we introduced each of the cDNAs into human embryonic kidney 293 cells and examined whether it activated the transcription of a luciferase reporter gene driven by a promoter containing the consensus NF-kappaB binding sites. In total, we identified 299 cDNAs that activate the NF-kappaB pathway, and we classified them into 83 genes, including 30 characterized activator genes of the NF-kappaB pathway, 28 genes whose involvement in the NF-kappaB pathways have not been characterized and 25 novel genes. We then carried out a similar analysis for the identification of genes that activate the MARK pathway, utilizing the same cDNA resource. We assayed 145 000 cDNAs and identified 57 genes that activate the MARK pathway. Interestingly, 27 genes were overlapping between the NF-kappaB and the MAPK pathways, which may indicate that these genes play cross-talking roles between these two pathways.
Three methylation epigenotypes exist in colorectal cancer, and suitable classification markers have been developed. Intermediate-methylation epigenotype with KRAS-mutation(+) correlated with worse prognosis.
Physarum actinin previously isolated [Hatano, S., & Owaribe, K. (1976) in Cell Motility (Goldman, R., Pollard, T., & Rosenbaum, J., Eds.) Vol. 3, Book B, p 499, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY] was found to be a 1:1 complex of actin and fragmin which is a regulatory factor in the formation of actin filaments. Since fragmin did not contain a cysteine residue, it was purified from the complex by the selective cleavage of actin with 2-nitro-5-thiocyanobenzoic acid, followed by column chromatography. Fragmin had nearly the same molecular weight as actin, but had a quite different amino acid composition. When added to G-actin before polymerization, fragmin accelerated the initial viscosity increase of actin solutions induced by salts, but kept the final viscosity much lower than normal F-actin. When added to F-actin after polymerization, fragmin drastically reduced the viscosity of actin solutions. In both cases, the final products of reaction of fragmin with actin were short F-actin filaments. The number average length of the filaments decreased with the increasing molar ratio of fragmin to actin, and the length distribution was always exponential. Fragmin required for its activity a concentration of free Ca2+ higher than 10(-6) M. When the concentration of free Ca2+ was lower than 10(-7) M, fragmin affected neither actin polymerization nor F-actin. The regulation by Ca2+ was reversible.
pH-Sensitive dextran derivatives having 3-methylglutarylated residues (MGlu-Dex) were prepared by reacting dextran with 3-methyl-glutaric anhydride. MGlu-Dex changed the protonation state and their characteristics from hydrophilic to hydrophobic in neutral and acidic pH regions. Surface modification of egg yolk phosphatidylcholine liposomes with MGlu-Dex produced highly pH-sensitive liposomes that were stable at neutral pH but which were destabilized strongly in the weakly acidic pH region. MGlu-Dex-modified liposomes were taken up efficiently by dendritic cells and delivered entrapped ovalbumin (OVA) molecules into the cytosol. When MGlu-Dex-modified liposomes loaded with OVA were administered subcutaneously to mice, the antigen-specific humoral and cellular immunity was induced more effectively than the unmodified liposomes loaded with OVA. Furthermore, administration of MGlu-Dex-modified liposomes loaded with OVA to mice bearing E.G7-OVA tumor significantly suppressed tumor growth and extended the mice survival. Results suggest that MGlu-Dex-modified liposomes are promising for the production of safe and potent antigen delivery systems that contribute to the establishment of efficient cancer immunotherapy.
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