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Abstract The interactions of adherent cells with their insoluble extracellular matrices are complex and challenging to study in the laboratory. Approaches from interface science have been important to preparing models of the biological matrix wherein discrete ligands are immobilized and interact with cellular receptors. A recent theme has been to develop dynamic substrates, where the activities of immobilized ligands can be modulated in real-time during cell culture. This short opinion reviews the strategies to manipulate ligand activity, highlights recent work that has advanced the field and discusses the applications that have been enabled. This work suggests that dynamic substrates will continue to find important uses in basic and applied biointerfaces. Graphical abstract Image 1 Highlights • Cell-surface receptors bind to protein matrix ligands to adhere and receive signals. • In tissue, the interactions are regulated dynamically to control cell behavior. • Bio-interface science seeks to design dynamic substrates that mimic biological matrix. • Strategies based on optical, electrical, mechanical and chemical cues are described. • Dynamic substrates enable studies in biology, cell-based sensing, and diagnostics. [ABSTRACT FROM AUTHOR]

Abstract: The extracellular matrix is an insoluble aggregate of large proteins and glycosoaminoglycans that comprises the microenvironment of cells in tissue. The matrix displays a host of ligands that interact with cell-surface receptors to mediate the attachment and spreading of cells and regulate signaling processes. Studies of cell–matrix interactions and downstream signaling processes commonly employ substrates having an adsorbed layer of protein and are challenged by the difficulty in controlling the structure and activity of the immobilized protein. Significant effort has been directed towards the development of model substrates that present adhesion ligands in defined densities, orientations and environments. Among these approaches, self-assembled monolayers of alkanethiolates on gold offer a high level of control over the molecular structure of the surface and are well-suited to studies of cell adhesion. This review describes the design and use of monolayers for applications in cell biology, including the use of monolayers to evaluate the roles of peptide and protein ligands in cell–matrix interactions, the development of methods to pattern ligands on monolayers and applications to cell biology, the development of dynamic monolayers that can switch the activities of ligands presented to an adherent cell, and the rewiring of interactions between a cell and its substrate. These examples illustrate the flexibility inherent to monolayers for applications in cell biology. [Copyright &y& Elsevier]

Peptide arrays have attracted wide interest as tools for discovering biochemical interactions. Because many protein binding and enzyme activities are directed towards peptides, the preparation of arrays having hundreds to thousands of immobilized peptides offers an unprecedented opportunity for identifying interactions of proteins. This short opinion reviews recent progress in the preparation of peptide arrays and their use in the characterization of biomolecular interactions and the discovery of new reagents for biological researches. This body of work establishes the feasibility of this technology and suggests that it will find much wider use in research groups. [Copyright &y& Elsevier]

Focuses on the technical challenges in the development of a protein-chip technology that matches the availability and performance of gene chips. Essential quality of protein chips to researchers in biology and to commercial programs in drug discovery and diagnostics; Survey of opportunities for immobilizing large numbers of proteins using detection methods.

Recent research has enhanced the development of substrates that serve as models of extracellular matrix and their use in studies of cell adhesion and migration. Advances include the development of methods to prepare substrates having ligands immobilized in controlled densities and patterns, and recent work that is developing dynamic substrates which can modulate, in real-time, the activities of ligands. These technologies are providing new opportunities for studies of cell–extracellular-matrix interactions. [Copyright &y& Elsevier]

Focuses on a study which outlined several strategies that are based on electrical, photochemical, thermal and mechanical forces for designing interfaces that are active and can signal changes in the behaviors of attached cells. Methods of surface modification; Comparison of transduction strategies; Applications for dynamic substrates.

The development of peptide and protein microarrays has created enormous opportunities in biomedical research. Current chip-based assays are well suited for identifying candidate protein or enzyme activities but still require conventional solution phase experiments to validate hits. Here, three surface-engineering strategies for microarray design are described and are illustrated in the development of a peptide chip for the quantitative analysis of kinase activity on solid support. These strategies promise to widen the application of microarrays by permitting the evaluation of hits in a chip-based format. [Copyright &y& Elsevier]

This work uses global gene expression analysis to compare the extent to which model substrates presenting peptide adhesion motifs mimic the use of conventional extracellular matrix protein coated substrates for cell culture. We compared the transcriptional activities of genes in cells that were cultured on matrix-coated substrates with those cultured on self-assembled monolayers presenting either a linear or cyclic RGD peptide. Cells adherent to cyclic RGD were most similar to those cultured on native ECM, while cells cultured on monolayers presenting the linear RGD peptide had transcriptional activities that were more similar to cells cultured on the uncoated substrates. This study suggests that biomaterials presenting the cyclic RGD peptide are substantially better mimics of extracellular matrix than are uncoated materials or materials presenting the common linear RGD peptide. [ABSTRACT FROM AUTHOR]

We herein disclose a series of compounds with potent inhibitory activities towards histone deacetylases (HDAC) and cyclooxygenases (COX). These compounds potently inhibited the growth of cancer cell lines consistent with their anti-COX and anti-HDAC activities. While compound 2b showed comparable level of COX-2 selectivity as celecoxib, compound 11b outperformed indomethacin in terms of selectivity towards COX-2 relative to COX-1. An important observation with our lead compounds ( 2b , 8 , 11b , and 17b ) is their enhanced cytotoxicity towards androgen dependent prostate cancer cell line (LNCaP) relative to androgen independent prostate cancer cell line (DU-145). Interestingly, compounds 2b and 17b arrested the cell cycle progression of LNCaP in the S-phase, while compound 8 showed a G0/G1 arrest, similar to SAHA. Relative to SAHA, these compounds displayed tumor-selective cytotoxicity as they have low anti-proliferative activity towards healthy cells (VERO); an attribute that makes them attractive candidates for drug development. [ABSTRACT FROM AUTHOR]

Inhibition of the enzymatic activity of histone deacetylase (HDAC) is a promising therapeutic strategy for cancer treatment and several distinct small molecule histone deacetylase inhibitors (HDACi) have been reported. We have previously identified a new class of non-peptide macrocyclic HDACi derived from 14- and 15-membered macrolide skeletons. In these HDACi, the macrocyclic ring is linked to the zinc chelating hydroxamate moiety through a para -substituted aryl-triazole cap group. To further delineate the depth of the SAR of this class of HDACi, we have synthesized series of analogous compounds and investigated the influence of various substitution patterns on their HDAC inhibitory, anti-proliferative and anti-inflammatory activities. We identified compounds 25b and 38f with robust anti-proliferative activities and compound 26f (IC 50 47.2 nM) with superior anti-inflammatory (IC 50 88 nM) activity relative to SAHA. [ABSTRACT FROM AUTHOR]

Histone deacetylase (HDAC) inhibition has recently emerged as a novel therapeutic approach for the treatment of various pathological conditions including cancer. Currently, two HDAC inhibitors (HDACi) – Vorinostat and Romidepsin – have been approved for the treatment of cutaneous T-cell lymphoma. However, HDACi remain ineffective against solid tumors and are associated with adverse events including cardiotoxicity. Targeted delivery may enhance the therapeutic indices of HDACi and enable them to be efficacious against solid tumors. We showed herein that morphing of folic and pteroic acids into the surface recognition group of HDACi results in hydroxamate and benzamide HDACi which derived tumor homing by targeting folate receptor (FR), a receptor commonly overexpressed in solid tumors. We observed a correlation between the potency of HDAC1 inhibition and cytotoxicity as only the potent pteroate hydroxamates, 11d and 11e , displayed antiproliferative activity against two representative FR-expression cancer cells. Our observation further supports the previous results which suggest that for a drug to be successfully targeted using the FR, it must be extremely potent against its primary target as the FR has a low delivery efficiency. [ABSTRACT FROM AUTHOR]

Histone deacetylase inhibitors (HDACi) pleiotropy is largely due to their nonselective inhibition of various cellular HDAC isoforms. Connecting inhibition of a specific isoform to biological responses and/or phenotypes is essential toward deconvoluting HDACi pleiotropy. The contribution of classes I and II HDACs to the antileishmanial activity of HDACi was investigated using the amastigote and promastigote forms of Leishmania donovani . We observed that the antileishmanial activities of HDACi are largely due to the inhibition of HDAC6-like activity. This observation could facilitate the development of HDACi as antileishmanial agents. [ABSTRACT FROM AUTHOR]

Abstract: Significant efforts have addressed the role of vimentin intermediate filaments (VIF) in cell motility, shape, adhesion and their connections to microfilaments (MF) and microtubules (MT). The present work uses micropatterned substrates to control the shapes of mouse fibroblasts and demonstrates that the cytoskeletal elements are dependent on each other and that unlike MF, VIF are globally controlled. For example, both square and circle shaped cells have a similar VIF distribution while MF distributions in these two shapes are quite different and depend on the curvature of the shape. Furthermore, in asymmetric and polarized shaped cells VIF avoid the sharp edges where MF are highly localized. Experiments with vimentin null mouse embryonic fibroblasts (MEFs) adherent to polarized (teardrop) and un-polarized (dumbbell) patterns show that the absence of VIF alters microtubule organization and perturbs cell polarity. The results of this study also demonstrate the utility of patterned substrates for quantitative studies of cytoskeleton organization in adherent cells. [Copyright &y& Elsevier]

Abstract: This paper describes an enzymatic approach to obtain a thio-containing UDP-GlcNAc analog. We use an assay based on capture of the carbohydrate and analysis by mass spectrometry to quantitatively characterize the activity of this unnatural sugar donor in a LgtA-mediated glycosylation reaction. [Copyright &y& Elsevier]

Abstract: A library of 11 UDP-N-acetylglucosamine analogs were rapidly screened for their activities as donors for the Neisseria meningitidis β1,3-N-acetylglucosaminyltransferase (LgtA) by direct on-chip reaction and detection with SAMDI-TOF mass spectrometry. Six of the analogs were active in this assay and were analyzed by SAMDI to characterize the kinetics toward LgtA. The analysis revealed that substitutions on C-2, C-4, and C-6 affect the activity of the donors, with bulky groups at these positions decreasing affinity of the donors for the enzyme, and also revealed that activity is strongly affected by the stereochemistry at C-3, but not C-4, of the donor. The study is also significant because it demonstrates that SAMDI can be used to both profile glycosyltransferase activities and to provide a quantitative assessment of enzyme activity. [Copyright &y& Elsevier]

Estrogen receptors a (ERα) and β (ERβ) have distinct functions and differential expression in certain tissues. These differences have stimulated the search for subtype-selective ligands. Therapeutically, such ligands offer the potential to target specific tissues or pathways regulated by one receptor subtype without affecting the other. As reagents, they can be utilized to probe the physiological functions of the ER subtypes to provide information complementary to that obtained from knock-out animals. A fluorescence resonance energy transfer-based assay was used to screen a 10,000-compound chemical library for ER agonists. From the screen, we identified a family of ERR-selective agonists whose members contain bulky oxabicyclic scaffolds in place of the planar scaffolds common to most ER ligands. These agonists are 10-50-fold selective for ERβ in competitive binding assays and up to 60-fold selective in transactivation assays. The weak uterotrophic activity of these ligands in immature rats and their ability to stimulate expression of an ERβ regulated gene in human U2OS osteosarcoma cells provides more physiological evidence of their ERβ-selective nature. To provide insight into the molecular mechanisms of their activity and selectivity, we determined the crystal structures of the ERα ligand-binding domain (LBD) and a peptide from the glucocorticoid receptor-interacting protein 1 (GRIP1) coactivator complexed with the ligands OBCP-3M, OBCP-2M, and OBCP-1M. These structures illustrate how the bicyclic scaffolds of these ligands are accommodated in the flexible ligand-binding pocket of ER. A comparison of these structures with existing ER structures suggests that the ERβ selectivity of OBCP ligands can be attributed to a combination of their interactions with Met-336 in ERβ and Met-421 in ERα. These bicyclic ligands show promise as lead compounds that can target ERβ. In addition, our understanding of the molecular determinants of their subtype selectivity provides a useful starting point for developing other ER modulators belonging to this relatively new structural class. [ABSTRACT FROM AUTHOR]

Focuses on the selection of a quinazoline compound which inhibits adenylyl cyclase activity. Prediction of binding to the adenine portion of the adenosine triphosphate binding site on edema factor (EF); Activation of the EF by host calcium sensor, calmodulin; Findings of the surface plasmon resonance spectroscopic analysis.