Label-free screening of bio-molecular interactions

Cooper, Matthew A.

doi:10.1007/s00216-003-2111-y

Cited by 416 publications

(310 citation statements)

References 112 publications

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“…To prove that cladosporols A and B are bona fide PPARc ligands and to assess their binding affinity, we employed a surface plasmon resonance (SPR)-based approach [41]. The acquired sensorgrams showed that both compounds interact with the protein (Fig.…”

Section: Cladosporol B Displays a Different Pparc-mediated Transcriptmentioning

confidence: 99%

The antiproliferative and proapoptotic effects of cladosporols A and B are related to their different binding mode as PPARγ ligands

Zurlo

Ziccardi

Votino

et al. 2016

Biochemical Pharmacology

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a b s t r a c tCladosporols are secondary metabolites from Cladosporium tenuissimum characterized for their ability to control cell proliferation. We previously showed that cladosporol A inhibits proliferation of human colon cancer cells through a PPARc-mediated modulation of gene expression. In this work, we investigated cladosporol B, an oxidate form of cladosporol A, and demonstrate that it is more efficient in inhibiting HT-29 cell proliferation due to a robust G0/G1-phase arrest and p21 waf1/cip1 overexpression. Cladosporol B acts as a PPARc partial agonist with lower affinity and reduced transactivation potential in transient transfections as compared to the full agonists cladosporol A and rosiglitazone. Site-specific PPARc mutants and surface plasmon resonance (SPR) experiments confirm these conclusions. Cladosporol B in addition displays a sustained proapoptotic activity also validated by p21 waf1/cip1 expression analysis in the presence of the selective PPARc inhibitor GW9662. In the DMSO/H 2 O system, cladosporols A and B are unstable and convert to the ring-opened compounds 2A and 2B. Finally, docking experiments provide the structural basis for full and partial PPARc agonism of 2A and 2B, respectively. In summary, we report here, for the first time, the structural characteristics of the binding of cladosporols, two natural molecules, to PPARc. The binding of compound 2B is endowed with a lower transactivation potential, higher antiproliferative and proapoptotic activity than the two full agonists as compound 2A and rosiglitazone (RGZ).

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Section: Cladosporol B Displays a Different Pparc-mediated Transcriptmentioning

confidence: 99%

The antiproliferative and proapoptotic effects of cladosporols A and B are related to their different binding mode as PPARγ ligands

Zurlo

Ziccardi

Votino

et al. 2016

Biochemical Pharmacology

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“…[3][4][5][6] SPR is attractive owing to several inherent advantages (e.g., labelfree analysis, simplicity, cost-effectiveness, and high sensitivity). [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] The SPR resonance angle variation is dependent on various physicochemical processes occurring at the SPR substrate (a thin metal film or a chemically modified metal surface) and/or the substrate/ solution interface.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Surface Plasmon Resonance Spectroscopy at Bilayered Silver/Gold Films

et al. 2006

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Bilayered silver/gold films (gold deposited on top of the silver film) were used as substrates for electrochemical surface plasmon resonance spectroscopy (EC-SPR). EC-SPR responses of electrochemical deposition/stripping of copper and redox-induced conformation changes of cytochrome c immobilized onto self-assembled monolayers preformed at these substrates were measured. Influence of the Ag layer thickness and the double-layer capacitance on the EC-SPR behavior was investigated. The results demonstrated that the bilayered Ag/Au metal films produce a sharper SPR dip profile than pure Au films and retain the high chemical stability of Au films. Contrary to the result by the Fresnel calculation that predicts a greater fraction of Ag in the bilayered film should result in a greater signal-to-noise ratio, the EC-SPR sensitivity is dependent on both the Ag/Au thickness ratio and the chemical modification of the surface. Factors affecting the overall SPR sensitivity at the bilayered films, such as the film morphology, potential-induced excess surface charges, and the adsorbate layer were investigated. Forming a compact adsorbate layer at the bilayered film diminishes the effect of potential-induce excess surface charges on the SPR signal and improves the overall EC-SPR sensitivity. For the case of redox-induced conformation changes of cytochrome c, the SPR signal obtained at the bilayered silver/gold film is 2.7 times as high as that at a pure gold film.

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“…Surface plasmon resonance (SPR) is one technique amenable to such measurements. SPR is an optical sensor technique that has the advantage of being able to take real-time measurements using low concentrations of unlabeled biologicals [reviewed in Cooper 2003]. …”

Section: (I) Introductionmentioning

confidence: 99%

Ligand rebinding: self-consistent mean-field theory and numerical simulations applied to surface plasmon resonance studies

et al. 2005

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Rebinding of dissociated ligands from cell surface proteins can confound quantitative measurements of dissociation rates important for characterizing the affinity of binding interactions. This can be true also for in vitro techniques such as surface plasmon resonance (SPR). We present experimental results using SPR for the interaction of insulin-like growth factor-I (IGF-I) with one of its binding proteins, IGF binding protein-3 (IGFBP-3), and show that the dissociation, even with the addition of soluble heparin in the dissociation phase, does not exhibit the expected exponential decay characteristic of a 1:1 binding reaction. We thus consider the effect of (multiple) rebinding events and, within a self-consistent mean-field approximation, we derive the complete mathematical form for the fraction of bound ligands as a function of time. We show that, except for very low association rate and surface coverage, this function is non-exponential at all times, indicating that multiple rebinding events strongly influence dissociation even at early times. We compare the mean-field results with numerical simulations and find good agreement, although deviations are measurable in certain cases. Our analysis of the IGF-I-IGFBP-3 data indicates that rebinding is prominent for this system and that the theoretical predictions fit the experimental data well. Our results provide a means for analyzing SPR biosensor data where rebinding is problematic and a methodology to do so is presented.1 Present Address: Max Planck Institut für Physik komplexer Systeme, Nöthnitzer Stra e 38, 01187 Dresden, Germany. (i) IntroductionSignal transduction via transmembrane receptor proteins is initiated by extracellular binding with specific proteins known as growth factors. These interactions tend to be of high affinity and, in many systems, are regulated by binding proteins present in the extracellular environment. Insulin-like growth factor-I (IGF-I) constitutes one prominent example of such a growth factor. Cell signaling is transmitted by direct interaction with the IGF-I receptor but this binding can be impacted by solution and cell-associated IGF binding proteins (IGFBPs), of which there are at least six. Quantification of the interactions of IGF-I with IGFBPs is critical if one is to understand how changes in expression and secretion will impact IGF-I signaling. Surface plasmon resonance (SPR) is one technique amenable to such measurements. SPR is an optical sensor technique that has the advantage of being able to take real-time measurements using low concentrations of unlabeled biologicals [reviewed in Cooper 2003].Quantification of IGF-I interactions with both cell surface receptors and IGFBPs using SPR has been performed as a means of evaluating and predicting the competition between these molecules for IGF-I. Studies have used immobilized IGF-I [Wong et al. 1999;Dubaquie and Lowman 1999;Galanis et al. 2001;Fong et al. 2002; Vorwerk et al. 2002], IGF-I receptor [Jansson et al. 1997], or IGFBPs [Heding et al. 1996Jansson et al. ...

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Label-free screening of bio-molecular interactions

Cited by 416 publications

References 112 publications

The antiproliferative and proapoptotic effects of cladosporols A and B are related to their different binding mode as PPARγ ligands

The antiproliferative and proapoptotic effects of cladosporols A and B are related to their different binding mode as PPARγ ligands

Electrochemical Surface Plasmon Resonance Spectroscopy at Bilayered Silver/Gold Films

Ligand rebinding: self-consistent mean-field theory and numerical simulations applied to surface plasmon resonance studies

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