Intracellular cargo delivery by an octaarginine transporter adapted to target prostate cancer cells through cell surface protease activation

Delivery of therapeutics and imaging agents to target tissues requires localization and activation strategies with molecular specificity. Cell-associated proteases can be used for these purposes in a number of pathologic conditions, and their enzymatic activities can be exploited for activation strategies. Here, molecules based on the d-arginine octamer (r8) protein-transduction domain (PTD, also referred to as molecular transporters) have been adapted for selective uptake into cells only after proteolytic cleavage of a PTD-attenuating sequence by the prostate-specific antigen (PSA), an extracellular protease associated with the surface and microenvironment of certain prostate cancer cells. Convergent syntheses of these activatable PTDs (APTDs) are described, and the most effective r8 PTD-attenuating sequence is identified. The conjugates are shown to be stable in serum, cleaved by PSA, and taken up into Jurkat (human T cells) and PC3M prostate cancer cell lines only after cleavage by PSA. These APTD peptide-based molecules may facilitate targeted delivery of therapeutics or imaging agents to PSA-expressing prostate cancers.     

Preparation and characterization of urea-formaldehyde-pepsin bioconjugate: a new biocatalyst system

This study describes the synthesis of urea formaldehyde (UF) microspheres by a dispersion polycondensation polymerization method. These microspheres with proper F/U molar ratio can provide highly reactive groups, capable of further condensation with the amino acid residues of enzyme/proteins. Presence of methylols groups in UF microspheres was confirmed by 13C NMR study. Pepsin, a proteolytic enzyme, was immobilized on the UF microspheres to form bioconjugate system. As compared to the free enzyme in solution, the pepsin in the bioconjugate system exhibited significantly enhanced pH and temperature stability. The urea-formaldehyde-pepsin bioconjugate system also exhibited excellent proteolytic activity over eight successive reuse cycles with more than 50% of initial activity. A highlight of this new biocatalyst is the ease with which separation of this biocatalyst from the reaction medium may be achieved by mild centrifugation.     

Structural organization of human Cu-transporting ATPases: learning from building blocks

Copper-transporting ATPases (Cu-ATPases) ATP7A and ATP7B play an essential role in human physiological function. Their primary function is to deliver copper to the secretory pathway and export excess copper from the cell for removal or further utilization. Cells employ Cu-ATPases in numerous physiological processes that include the biosynthesis of copper-dependent enzymes, lactation, and response to hypoxia. Biochemical studies of human Cu-ATPases and their orthologs have demonstrated that Cu-ATPases share many common structural and mechanistic characteristics with other members of the P-type ATPase family. Nevertheless, the Cu-ATPases have a unique coordinate environment for their ligands, copper and ATP, and additional domains that are required for sophisticated regulation of their intracellular localization and activity. Here, we review recent progress that has been made in understanding the structure of Cu-ATPases from the analysis of their individual domains and orthologs from microorganisms, and speculate about the implications of these findings for the function and regulation of human copper pumps.     

Design and synthesis of harzialactone analogues: promising anticancer agents

New homologues of harzialactone were synthesized using D-glucose as chiral template. Wittig reaction to introduce aromatic moiety in 10 and chemoselective anomeric oxidation of 13 were used as key reactions in our synthesis. Anticancer activity of these target molecules was assessed against five cancer cell lines, P388D1, HL60, COLO-205, Zr-75-1 and HeLa. Both compound 5 and 6, showed significant activity against colon cancer (COLO-205) and cervical cancer (HeLa) and moderate with others. To the best of our knowledge, this is the first report of harzialactone analogues as potent inhibitors of human colon and cervical cancer.     

One pot synthesis and SAR of some novel 3-substituted 5,6-diphenyl-1,2,4-triazines as antifungal agents

An improved protocol for the synthesis of a novel series of 1,2,4-triazines possessing 1,2,3-triazole and piperidine ring using 1-(1-substituted piperidin-4-yl)-1H-1,2,3-triazole-4-carbohydrazide, benzil, ammonium acetate and ZrOCl₂·8H₂O as a catalyst in ethanol–water has been presented. The yields obtained are in the range of 87–94%. All the synthesized compounds (4a–4l) are novel and were evaluated for their in vitro antifungal activity. SAR for the series has been developed by comparing their MIC values with miconazole and fluconazole. Based on activity data SAR for the series has been developed. Compound 4c from the series was equipotent to miconazole against Candida albicans (MIC-25), Aspergillus niger (MIC-12.5) and Cryptococcus neoformans (MIC-25). Compound 4d was equipotent with miconazole against all tested organisms except Cryptococcus neoformans. Also compound 4i was equipotent with miconazole against C. albicans, A. niger and Fusarium oxysporum.     

The analog of cGAMP,c-di-AMP,activates STING mediated cell death pathway in estrogen-receptor negative breast cancer cells

Apoptosis - Immune adaptor protein like STING/MITA regulate innate immune response and plays a critical role in inflammation in the tumor microenvironment and regulation of metastasis including...     

Luminescence in Li3Al2(PO4)3:Eu2+

A series of efficient Li₃Al₂(PO₄)₃:Eu²⁺ novel phosphors were synthesized by the facile combustion method. The effects of dopant on the luminescence behavior of Li₃Al₂(PO₄)₃ phosphor were also investigated. The phosphors were characterized by X‐ray diffraction, field emission scanning electron microscope and photoluminescence techniques. The result shows that all samples can be excited efficiently by near‐ultraviolet excitation under 310 nm. The emission was observed for Li₃Al₂(PO₄)₃:Eu²⁺ phosphor at 425 nm, which corresponded to the d → f transition. The concentration quenching of Eu²⁺ was observed in Li₃Al₂(PO₄)₃:Eu²⁺ when the Eu concentration was at 0.5 mol%. The prepared powders exhibited intense blue emission at the 425 nm owing to the Eu²⁺ ion by Hg‐free excitation at 310 nm (i.e., solid‐state lighting excitation). Consequently, the availability of such a phosphor will significantly help in the development of blue‐emitting solid‐state lighting applications. Copyright © 2012 John Wiley & Sons, Ltd.     

Novel isoforms of proteinaceous α-amylase inhibitor (α-AI) from seed extract of Albizia lebbeck

Proteinaceous inhibitors of digestive α-amylase occur naturally in leguminous seeds and find applications in agriculture and clinical studies. We have detected and isolated eight novel α-amylase inhibitor isoforms in the seed extract of Albizia lebbeck. They are designated as AL-αAI-1 to AL-αAI-8. These isoforms specifically inhibit human salivary α-amylase and porcine pancreatic α-amylase. The occurrence and profile of α-amylase inhibitor isoforms were revealed by 7 % native-PAGE containing 0.1 % starch. The apparent molecular weights of native bands of AL-αAIs were 97.4, 68.6, 61.0, 57.2, 56.0, 54.7, 51.1, and 47.7 kDa, respectively. Partial purification of potent α-amylase inhibitor was achieved using ammonium sulfate fractionation and gel filtration chromatography on G-100 Sephadex column followed by preparative gel electrophoresis. SDS-PAGE analysis of partially purified AL-αAI showed two polypeptide bands of ~35.8 and ~32.6 kDa. All these isoforms showed effective resistance to in vitro proteolysis by pepsin, trypsin, and chymotrypsin. These inhibitors are stable over a wide range of pH and temperature and have optimum activity at pH 7 and at 37 °C. The finding and information obtained in the present investigation about novel isoforms of α-amylase inhibitors from A. lebbeck could be important and may find applications in clinical studies to modulate starch digestion and glycemic index.