- Potent antiproliferative activity of bradykinin B2 receptor selective agonist FR-190997 and analogue structures thereof: A paradox resolved?
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Βradykinin stimulation of B2 receptor is known to activate the oncogenic ERK pathway and overexpression of bradykinin receptors B1 and B2 has been reported to occur in glioma, colorectal and cervical cancers. B1R and B2R antagonists have been shown to reverse tumor proliferation and invasion. Paradoxically, B1R and B2R agonism has also been reported to elicit antiproliferative benefits. In order to complement the data accumulated to date with the natural substrate bradykinin and peptidic B2R antagonists, we decided to examine for the first time the response elicited by B2R stimulation in breast cancer lines with a non-peptidic small molecule B2R agonist. We synthesized and assessed the highly selective and potent B2R partial agonist FR-190997 in MCF-7 and MDA-MBA-231 breast cancer lines and found it possessed significant antiproliferative activity (IC50 2.14 and 0.08 μΜ, respectively). The modular nature of FR-190997 allowed us to conduct a focused SAR study and discover compound 10 which exhibits subnanomolar antiproliferative activity (IC 50 0.06 nΜ) in the TNBC MDA-MBA-231 cell line. This performance surpasses, in most cases by several orders of magnitude, those of established anticancer agents and FDA-approved breast cancer drugs. In line with the established literature we suggest that this remarkable activity precipitates from a dual mode of action involving agonist-induced receptor internalization/degradation combined with sequestration of functional intracellular B2 receptors and inhibition of the associated endosomal signaling. The latter mode may be realized by appropriate ligands regardless of B2R agonist/antagonist designation which only relates to membrane residing GCPRs. Under this prism the controversy over the antiproliferative effects of B2 agonists and antagonists is potentially neutralized.
- Rassias, Gerasimos,Leonardi, Sofia,Rigopoulou, Dionisia,Vachlioti, Eleanna,Afratis, Konstantinos,Piperigkou, Zoi,Koutsakis, Christos,Karamanos, Nikos K.,Gavras, Haralambos,Papaioannou, Dionissios
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- A New Series of Highly Potent Non-Peptide Bradykinin B2 Receptor Antagonists Incorporating the 4-Heteroarylquinoline Framework. Improvement of Aqueous Solubility and New Insights into Species Difference
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Introduction of nitrogen-containing heteroaromatic groups at the 4-position of the quinoline moiety of our non-peptide B2 receptor antagonists resulted in enhancing binding affinities for the human B 2 receptor and reducing binding affinities for the guinea pig one, providing new structural insights into species difference. A CoMFA study focused on the diversity of the quinoline moiety afforded correlative and predictive QSAR models of binding for the human B2 receptor but not for the guinea pig one. A series of 4-(1-imidazolyl)quinoline derivatives could be dissolved in a 5% aqueous solution of citric acid up to a concentration of 10 mg/mL. A representative compound 48a inhibited the specific binding of [ 3H]BK to the cloned human B2 receptor expressed in Chinese hamster ovary cells with an IC50 value of 0.26 nM and significantly inhibited BK-induced bronchoconstriction in guinea pigs even at 1 μg/kg by intravenous administration.
- Sawada, Yuki,Kayakiri, Hiroshi,Abe, Yoshito,Imai, Keisuke,Mizutani, Tsuyoshi,Inamura, Noriaki,Asano, Masayuki,Aramori, Ichiro,Hatori, Chie,Katayama, Akira,Oku, Teruo,Tanaka, Hirokazu
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p. 1617 - 1630
(2007/10/03)
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