Abstract
Protein-protein interactions mediated through the C-terminal Bcl-2-associated athanogene (BAG) domain of BAG-1 are critical for cell survival and proliferation. Thioflavin S (NSC71948)-a mixture of compounds resulting from the methylation and sulfonation of primulin base-has been shown to dose-dependently inhibit the interaction between BAG-1 and Hsc70 in vitro. In human breast cancer cell lines, with high BAG-1 expression levels, Thioflavin S reduces the binding of BAG-1 to Hsc70, Hsp70, or CRAF and decreases proliferation and viability. Here, we report the development of a protocol for the purification and isolation of biologically active constituents of Thioflavin S and the characterization of the novel compound Thio-2. Thio-2 blocked the growth of several transformed cell lines, but had much weaker effects on untransformed cells. Thio-2 also inhibited the proliferation of melanoma cell lines that had become resistant to treatment with PLX4032, an inhibitor of mutant BRAF. In transformed cells, Thio-2 interfered with intracellular signaling at the level of RAF, but had no effect on the activation of AKT. Thio-2 decreased binding of BAG-1 to Hsc70 and to a lesser extent BRAF in vitro and in vivo, suggesting a possible mechanism of action. Given that tumors frequently develop resistance to kinase inhibitors during treatment, Thio-2 and related compounds may offer promising alternative strategies to currently available therapies.
©2013 AACR.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Aniline Compounds / isolation & purification
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Aniline Compounds / metabolism
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Aniline Compounds / pharmacology*
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Animals
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Antineoplastic Agents / isolation & purification
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Antineoplastic Agents / metabolism
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Antineoplastic Agents / pharmacology*
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Benzothiazoles / isolation & purification
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Benzothiazoles / metabolism
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Benzothiazoles / pharmacology*
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Binding Sites / drug effects
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Butadienes / pharmacology
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Cell Line
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Cell Proliferation / drug effects
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DNA-Binding Proteins / antagonists & inhibitors*
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DNA-Binding Proteins / metabolism
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Fluorescent Dyes / metabolism*
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Fluorescent Dyes / pharmacology
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HEK293 Cells
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HSC70 Heat-Shock Proteins / metabolism
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Humans
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Indoles / pharmacology
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MCF-7 Cells
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Mice
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Molecular Docking Simulation
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NIH 3T3 Cells
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Neoplasms / drug therapy*
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Neoplasms / pathology
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Nitriles / pharmacology
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Protein Binding / drug effects
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Proto-Oncogene Proteins B-raf / antagonists & inhibitors*
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Proto-Oncogene Proteins B-raf / metabolism
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Sulfonamides / pharmacology
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Thiazoles / chemistry*
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Transcription Factors / antagonists & inhibitors*
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Transcription Factors / metabolism
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Vemurafenib
Substances
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Aniline Compounds
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Antineoplastic Agents
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BCL2-associated athanogene 1 protein
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Benzothiazoles
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Butadienes
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DNA-Binding Proteins
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Fluorescent Dyes
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HSC70 Heat-Shock Proteins
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Indoles
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N-ethyl-4-(6-methylbenzo(d)thiazol-2-yl)aniline
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Nitriles
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Sulfonamides
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Thiazoles
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Transcription Factors
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U 0126
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Vemurafenib
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thioflavin T
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Proto-Oncogene Proteins B-raf