Aptamer–nanoparticle complexes as powerful diagnostic and therapeutic tools

Correct diagnosis and successful therapy are extremely important to enjoy a healthy life when suffering from a disease. To achieve these aims, various cutting-edge technologies have been designed and fabricated to diagnose and treat specific diseases. Among these technologies, aptamer–nanomaterial hybrids have received considerable attention from scientists and doctors because they have numerous advantages over other methods, such as good biocompatibility, low immunogenicity and controllable selectivity. In particular, aptamers, oligonucleic acids or peptides that bind to a specific target molecule, are regarded as outstanding biomolecules. In this review, several screening techniques for aptamers, also called systematic evolution of ligands by exponential enrichment (SELEX) methods, are introduced, and diagnostic and therapeutic aptamer applications are also presented. Furthermore, we describe diverse aptamer–nanomaterial conjugate designs and their applications for diagnosis and therapy.112618Ysciescopuskc

Overexpression of angiotensin II type 1 receptor in breast cancer cells induces epithelial–mesenchymal transition and promotes tumor growth and angiogenesis

The angiotensin II type I receptor (AGTR1) has been implicated in diverse aspects of human disease, from the regulation of blood pressure and cardiovascular homeostasis to cancer progression. We sought to investigate the role of AGTR1 in cell proliferation, epithelial-mesenchymal transition (EMT), migration, invasion, angiogenesis and tumor growth in the breast cancer cell line MCF7. Stable overexpression of AGTR1 was associated with accelerated cell proliferation, concomitant with increased expression of survival factors including poly(ADP-ribose) polymerase (PARP) and X-linked inhibitor of apoptosis (XIAP), as well as extracellular signal-regulated kinase (ERK) activation. AGTR1-overexpressing MCF7 cells were more aggressive than their parent line, with significantly increased activity in migration and invasion assays. These observations were associated with changes in EMT markers, including reduced E-cadherin expression and increased p-Smad3, Smad4 and Snail levels. Treatment with the AGTR1 antagonist losartan attenuated these effects. AGTR1 overexpression also accelerated tumor growth and increased Ki-67 expression in a xenograft model. This was associated with increased tumor angiogenesis, as evidenced by a significant increase in microvessels in the intratumoral and peritumoral areas, and enhanced tumor invasion, with the latter response associated with increased EMT marker expression and matrix metallopeptidase 9 (MMP-9) upregulation. In vivo administration of losartan significantly reduced both tumor growth and angiogenesis. Our findings suggest that AGTR1 plays a significant role in tumor aggressiveness, and its inhibition may have therapeutic implications. (C) 2016 Elsevier B.V. All rights reserved.111212Ysciescopu

Characterization of Multi-Functional Properties and Conformational Analysis of MutS2 from Thermotoga maritima MSB8

The MutS2 homologues have received attention because of their unusual activities that differ from those of MutS. In this work, we report on the functional characteristics and conformational diversities of Thermotoga maritima MutS2 (TmMutS2). Various biochemical features of the protein were demonstrated via diverse techniques such as scanning probe microscopy (SPM), ATPase assays, analytical ultracentrifugation, DNA binding assays, size chromatography, and limited proteolytic analysis. Dimeric TmMutS2 showed the temperature-dependent ATPase activity. The non-specific nicking endonuclease activities of TmMutS2 were inactivated in the presence of nonhydrolytic ATP (ADPnP) and enhanced by the addition of TmMutL. In addition, TmMutS2 suppressed the TmRecA-mediated DNA strand exchange reaction in a TmMutL-dependent manner. We also demonstrated that small-angle X-ray scattering (SAXS) analysis of dimeric TmMutS2 exhibited nucleotide- and DNA-dependent conformational transitions. Particularly, TmMutS2-ADPnP showed the most compressed form rather than apo-TmMutS2 and the TmMutS2-ADP complex, in accordance with the results of biochemical assays. In the case of the DNA-binding complexes, the stretched conformation appeared in the TmMutS2-four-way junction (FWJ)-DNA complex. Convergences of biochemical- and SAXS analysis provided abundant information for TmMutS2 and clarified ambiguous experimental results

Highly sensitive and selective in vitro diagnostics based on DNA probes and aptamers

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Enzyme-linked antibody aptamer assays based colorimetric detection of soluble fraction of activated leukocyte cell adhesion molecule

Patients with pancreatic and colorectal cancers have elevated levels of activated leukocyte cell adhesion molecule (ALCAM) in their blood compared to healthy individuals. To this end, sensitive detection of soluble fraction of ALCAM (sALCAM), also called CD166, was performed using enzyme-linked antibody aptamer (ELAA) assay. For the assay, aptamer specific for sALCAM was used as a capturing probe and polyclonal antibody modified with an enzyme was used as a detecting probe for colorimetric visualization. The ELAA assay was able to detect sALCAM as low as 0.31 ng/mL. In addition, the assay enabled the differentiation of sALCAM from other proteins in buffer as well as in human serum. The ELAA assay provides cost-effective, highly sensitive, and reproducible detection of sALCAM. (C) 2016 Elsevier B.V. All rights reserved.1111sciescopu

Superimpositions between the TmMutS2-ADPnP SAXS model and the ATPase structure/model.

<p>(<b>A</b>) The left structure is the ATPase domain of <i>T. aquaticus</i> MutS (TaqS-ATPase), and the right model is the predicted monomeric ATPase domain of TmMutS2 (TmS2-ATPase). (<b>B</b>) Superimpositions of the TmMutS2-ADPnP model to the dimeric TaqS-ATPase structure and the TmS2-ATPase model. The predicted conformers indicate the feasible structures of the dimeric TmS2-ATPase model.</p

Nicking endonuclease activity of TmMutS2.

<p>(<b>A</b>) The effects of various cations on the nicking endonuclease activity of TmMutS2. The cations were used at a concentration of 10 mM. The nick, l, and sc indicate the nicked, linearized, and supercoiled open circular DNA forms, respectively. (<b>B</b>) A mixture containing 2 µM TmMutS2/TmMutS2-Smr and 1.5 µM plasmid DNA (linear size, 3 kbp) was incubated at temperatures ranging from 20°C to 80°C in the presence or absence of Mg²⁺ (upper plot). In the middle of the gel, M indicates the DNA size marker. The lower plot presents the percentage yields of the nicked form. (<b>C</b>) Different activities of DNA digestion in the presence of ATP (lanes 3 to 7), ADP (lanes 8 to 12), and ADPnP (lanes 13 to 17). Lane 1 and 2 are TmMutS2 untreated- and treated-plasmid DNA bands in the absence of theh nucleotide at 60°C. Each nucleotide was utilized at a final concentration of 3 mM.</p

Superimpositions among the TmMutS2-dsDNA/-FWJ-DNA SAXS models and the Smr structure/model.

<p>(<b>A</b>) The left structure is the monomeric Smr domain of <i>H. sapiens</i> B3bp (B3bp-Smr), and the right model is the predicted monomeric Smr domain of TmMutS2 (TmS2-Smr). (<b>B</b>) Superimpositions of the TmMutS2-dsDNA/-FWJ-DNA SAXS model to the B3bp-Smr structure and the TmS2-Smr model. (<b>C</b>) Superimpositions of the TmMutS2-dsDNA/-FWJ-DNA SAXS model to the B3bp-exSmr SAXS model (green mesh). The B3bp-Smr structure (red) fits well with the B3bp-exSmr SAXS model.</p