TY - JOUR
T1 - Unambiguous Identification of β-Tubulin as the Direct Cellular Target Responsible for the Cytotoxicity of Chalcone by Photoaffinity Labeling
AU - Zhou, Bo
AU - Yu, Xingxin
AU - Zhuang, Chunlin
AU - Villalta, Peter
AU - Lin, Yong
AU - Lu, Junxuan
AU - Xing, Chengguo
N1 - Publisher Copyright:
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2016/7/5
Y1 - 2016/7/5
N2 - Chalcone is a simple and potentially privileged structure in medicinal chemistry with a diverse repertoire of biological activities, among which cytotoxicity is of particular interest. The sharp structure–activity relationship (SAR) for chalcone's cytotoxicity suggests structure-specific target interactions. Despite the numerous putative targets proposed, evidence for direct target interactions in cells is unavailable. In this study, guided by the sharp cytotoxic SAR, we developed a cytotoxic chalcone-based photoaffinity labeling (PAL) probe, (E)-3-(3-azidophenyl)-1-[3,5-dimethoxy-4-(prop-2-yn-1-yloxy)phenyl]-2-methylprop-2-en-1-one (C95; IC50: 0.38±0.01 μm), along with two structurally similar non-cytotoxic probes. These probes were used to search for the direct cellular target responsible for chalcone's cytotoxicity through intact cell-based PAL experiments, in which β-tubulin was identified to specifically interact with the cytotoxic probe (i.e., C95) but not the non-cytotoxic probes. A set of phenotypical and biochemical assays further reinforced β-tubulin as the cytotoxic target of chalcones. Peptide mass quantitation by mass spectrometric analysis revealed one peptide potentially labeled by C95, providing information on chalcone's binding site on β-tubulin.
AB - Chalcone is a simple and potentially privileged structure in medicinal chemistry with a diverse repertoire of biological activities, among which cytotoxicity is of particular interest. The sharp structure–activity relationship (SAR) for chalcone's cytotoxicity suggests structure-specific target interactions. Despite the numerous putative targets proposed, evidence for direct target interactions in cells is unavailable. In this study, guided by the sharp cytotoxic SAR, we developed a cytotoxic chalcone-based photoaffinity labeling (PAL) probe, (E)-3-(3-azidophenyl)-1-[3,5-dimethoxy-4-(prop-2-yn-1-yloxy)phenyl]-2-methylprop-2-en-1-one (C95; IC50: 0.38±0.01 μm), along with two structurally similar non-cytotoxic probes. These probes were used to search for the direct cellular target responsible for chalcone's cytotoxicity through intact cell-based PAL experiments, in which β-tubulin was identified to specifically interact with the cytotoxic probe (i.e., C95) but not the non-cytotoxic probes. A set of phenotypical and biochemical assays further reinforced β-tubulin as the cytotoxic target of chalcones. Peptide mass quantitation by mass spectrometric analysis revealed one peptide potentially labeled by C95, providing information on chalcone's binding site on β-tubulin.
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U2 - 10.1002/cmdc.201600150
DO - 10.1002/cmdc.201600150
M3 - Article
C2 - 27203512
AN - SCOPUS:84970993246
SN - 1860-7179
VL - 11
SP - 1436
EP - 1445
JO - ChemMedChem
JF - ChemMedChem
IS - 13
ER -