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Structural plasticity of a transmembrane peptide allows self-assembly into biologically active nanoparticles. Proc Natl Acad Sci U S A 2011; 108:9798-803. [PMID: 21628584 DOI: 10.1073/pnas.1014598108] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Significant efforts have been devoted to the development of nanoparticular delivering systems targeting tumors. However, clinical application of nanoparticles is hampered by insufficient size homogeneity, difficulties in reproducible synthesis and manufacturing, frequent high uptake in the liver, systemic toxicity of the carriers (particularly for inorganic nanoparticles), and insufficient selectivity for tumor cells. We have found that properly modified synthetic analogs of transmembrane domains of membrane proteins can self-assemble into remarkably uniform spherical nanoparticles with innate biological activity. Self-assembly is driven by a structural transition of the peptide that adopts predominantly a beta-hairpin conformation in aqueous solutions, but folds into an alpha-helix upon spontaneous fusion of the nanoparticles with cell membrane. A 24-amino acid peptide corresponding to the second transmembrane helix of the CXCR4 forms self-assembled particles that inhibit CXCR4 function in vitro and hamper CXCR4-dependent tumor metastasis in vivo. Furthermore, such nanoparticles can encapsulate hydrophobic drugs, thus providing a delivery system with the potential for dual biological activity.
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Hariprakasha HK, Kosakowska-Cholody T, Meyer C, Cholody WM, Stinson SF, Tarasova NI, Michejda CJ. Optimization of Naphthalimide-imidazoacridone with Potent Antitumor Activity Leading to Clinical Candidate (HKH40A, RTA 502). J Med Chem 2007; 50:5557-60. [DOI: 10.1021/jm7009777] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Humcha K. Hariprakasha
- Molecular Aspects of Drug Design Section, Structural Biophysics Laboratory, Center for Cancer Research, NCI-Frederick, Frederick, Maryland 21702, Developmental Therapeutics Program, NCI-Frederick, Frederick Maryland 21702, and Reata Pharmaceuticals, 2801 Gateway Drive, Suite 150, Irving, Texas
| | - Teresa Kosakowska-Cholody
- Molecular Aspects of Drug Design Section, Structural Biophysics Laboratory, Center for Cancer Research, NCI-Frederick, Frederick, Maryland 21702, Developmental Therapeutics Program, NCI-Frederick, Frederick Maryland 21702, and Reata Pharmaceuticals, 2801 Gateway Drive, Suite 150, Irving, Texas
| | - Colin Meyer
- Molecular Aspects of Drug Design Section, Structural Biophysics Laboratory, Center for Cancer Research, NCI-Frederick, Frederick, Maryland 21702, Developmental Therapeutics Program, NCI-Frederick, Frederick Maryland 21702, and Reata Pharmaceuticals, 2801 Gateway Drive, Suite 150, Irving, Texas
| | - Wieslaw M. Cholody
- Molecular Aspects of Drug Design Section, Structural Biophysics Laboratory, Center for Cancer Research, NCI-Frederick, Frederick, Maryland 21702, Developmental Therapeutics Program, NCI-Frederick, Frederick Maryland 21702, and Reata Pharmaceuticals, 2801 Gateway Drive, Suite 150, Irving, Texas
| | - Sherman F. Stinson
- Molecular Aspects of Drug Design Section, Structural Biophysics Laboratory, Center for Cancer Research, NCI-Frederick, Frederick, Maryland 21702, Developmental Therapeutics Program, NCI-Frederick, Frederick Maryland 21702, and Reata Pharmaceuticals, 2801 Gateway Drive, Suite 150, Irving, Texas
| | - Nadya I. Tarasova
- Molecular Aspects of Drug Design Section, Structural Biophysics Laboratory, Center for Cancer Research, NCI-Frederick, Frederick, Maryland 21702, Developmental Therapeutics Program, NCI-Frederick, Frederick Maryland 21702, and Reata Pharmaceuticals, 2801 Gateway Drive, Suite 150, Irving, Texas
| | - Christopher. J. Michejda
- Molecular Aspects of Drug Design Section, Structural Biophysics Laboratory, Center for Cancer Research, NCI-Frederick, Frederick, Maryland 21702, Developmental Therapeutics Program, NCI-Frederick, Frederick Maryland 21702, and Reata Pharmaceuticals, 2801 Gateway Drive, Suite 150, Irving, Texas
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Tarasov SG, Casas-Finet JR, Cholody WM, Kosakowska-Cholody T, Gryczynski ZK, Michejda CJ. Bisimidazoacridones: 2. Steady-state and Time-resolved Fluorescence Studies of Their Diverse Interactions with DNA¶§. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0780313bsatfs2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Röhr H, Trieflinger C, Rurack K, Daub J. Proton- and Redox-Controlled Switching of Photo- and Electrochemiluminescence in Thiophenyl-Substituted Boron-Dipyrromethene Dyes. Chemistry 2006; 12:689-700. [PMID: 16231292 DOI: 10.1002/chem.200500729] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A luminescent molecular switch in which the active thiol/disulfide switching element is attached to a meso-phenyl-substituted boron-dipyrromethene (BDP) chromophore as the signalling unit is presented. The combination of these two functional units offers great versatility for multimodal switching of luminescence: 1) deprotonation/protonation of the thiol/thiolate moiety allows the highly fluorescent meso-p-thiophenol-BDP and its nonfluorescent thiolate analogue to be chemically and reversibly interconverted, 2) electrochemical oxidation of the monomeric dyes yields the fluorescent disulfide-bridged bichromophoric dimer, also in a fully reversible process, and 3) besides conventional photoexcitation, the well separated redox potentials of the BDP also allow the excited BDP state to be generated electrochemically (i.e., processes 1) and 2) can be employed to control both photo- and electrochemiluminescence (ECL) of the BDP). The paper introduces and characterizes the various states of the switch and discusses the underlying mechanisms. Investigation of the ortho analogue of the dimer provided insight into potential chromophore-chromophore interactions in such bichromophoric architectures in both the ground and the excited state. Comparison of the optical and redox properties of the two disulfide dimers further revealed structural requirements both for redox switches and for ECL-active molecular ensembles. By employing thiol/disulfide switching chemistry and BDP luminescence features, it was possible to create a prototype molecular ensemble that shows both fully reversible proton- and redox-gated electrochemiluminescence.
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Affiliation(s)
- Holger Röhr
- Div. I.3, Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany
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Cholody WM, Kosakowska-Cholody T, Hollingshead MG, Hariprakasha HK, Michejda CJ. A New Synthetic Agent with Potent but Selective Cytotoxic Activity against Cancer. J Med Chem 2005; 48:4474-81. [PMID: 15974599 DOI: 10.1021/jm048946x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis of novel unsymmetrical bifunctional antitumor agents was accomplished by linking an imidazoacridone moiety to another polycyclic heteroaromatic moiety via linkers of various length and rigidity. These compounds bind to cellular DNA, but it is hypothesized that biological effects become manifested when the drug-DNA complexes interact with critical DNA binding proteins that are involved in repair and transcription. The most promising compound of the series, 4ad (WMC79), consists of an imidazoacridone linked to a 3-nitronaphthalimide moiety via a 1,4-dipropanopiperazine linker. It was found to be potently, but selectively, cytotoxic against colon cancers (GI(50) = 0.5 nM, LC(50) = 32 nM) and leukemias (GI(50) = 3.5 nM, LC(50) = 33 nM). Compound 4ad, which appears to be a candidate for further development as an anticancer drug, kills sensitive cells by induction of apoptosis. It also showed significant in vivo activity against HCT-116 colon cancer xenografts in nude mice. Other compounds in the series also exhibited antitumor properties, but they were significantly lower than that of 4ad.
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Affiliation(s)
- Wieslaw M Cholody
- Molecular Aspects of Drug Design, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, Maryland 21702, USA
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Tarasov SG, Casas-Finet JR, Cholody WM, Kosakowska-Cholody T, Gryczynski ZK, Michejda CJ. Bisimidazoacridones: 2. Steady-state and Time-resolved Fluorescence Studies of Their Diverse Interactions with DNA¶§. Photochem Photobiol 2003; 78:313-22. [PMID: 14626657 DOI: 10.1562/0031-8655(2003)078<0313:bsatfs>2.0.co;2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Several bisimidazoacridones (BIA) are potent, selective antineoplastic agents, whereas others have potent anti-human immunodeficiency virus activity. BIA are bifunctional agents that consist of two imidazoacridone (IA) chromophores held together by various linkers. Interaction of BIA with DNA has been postulated to be required for their biological activity. Fluorescence data on free and bound BIA suggest that the binding of BIA and similar drugs to DNA is driven by a transfer of hydrophobic molecules from aqueous media to the more amphiphilic DNA environment. Binding to DNA was sensitive to sequence and depended on the length and rigidity of the linker. Time-resolved fluorescence measurements showed that BIA adopt an extended conformation upon binding and that all of the molecules are tightly associated with DNA. Gel-shift and melting assays indicated that one of the aromatic residues of BIA is intercalated, whereas the other, together with a linker, resides in a groove, probably the minor groove. A continuum of structures may be possible where intercalation and classical minor groove binding are limiting structures. In general, the hypothesis for the mechanism of action of BIA wherein the unintercalated residue, accessible for additional interactions, captures a critical protein involved in repair or transcription, is consistent with this model.
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Affiliation(s)
- Sergey G Tarasov
- Molecular Aspects of Drug Design Section, Structural Biophysics Laboratory, National Cancer Institute at Frederick, Frederick, MD, USA.
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