TY - JOUR
T1 - Indolo[3,2-c]quinoline G-quadruplex stabilizers
T2 - A structural analysis of binding to the human telomeric G-quadruplex
AU - Lavrado, João
AU - Ohnmacht, Stephan A.
AU - Correia, Isabel
AU - Leitão, Clara
AU - Pisco, Sílvia
AU - Gunaratnam, Mekala
AU - Moreira, Rui
AU - Neidle, Stephen
AU - Santos, Daniel J.V.A.Dos
AU - Paulo, Alexandra
N1 - Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2015/5/1
Y1 - 2015/5/1
N2 - A library of 5-methylindolo[3,2-c]quinolones (IQc) with various substitution patterns of alkyldiamine side chains were evaluated for G-quadruplex (G4) binding mode and efficiency. Fluorescence resonance energy transfer melting assays showed that IQcs with a positive charge in the heteroaromatic nucleus and two weakly basic side chains are potent and selective human telomeric (HT) and gene promoter G4 stabilizers. Spectroscopic studies with HT G4 as a model showed that an IQc stabilizing complex involves the binding of two IQc molecules (2,9-bis{[3-(diethylamino)propyl]amino}-5-methyl-11H-indolo[3,2-c]quinolin-5-ium chloride, 3 d) per G4 unit, in two non-independent but equivalent binding sites. Molecular dynamics studies suggest that end-stacking of 3 d induces a conformational rearrangement in the G4 structure, driving the binding of a second 3 d ligand to a G4 groove. Modeling studies also suggest that 3 d, with two three-carbon side chains, has the appropriate geometry to participate in direct or water-mediated hydrogen bonding to the phosphate backbone and/or G4 loops, assisted by the terminal nitrogen atoms of the side chains. Additionally, antiproliferative studies showed that IQc compounds 2 d (2-{[3-(diethylamino)propyl]amino}-5-methyl-11H-indolo[3,2-c]quinolin-5-ium chloride) and 3 d are 7- to 12-fold more selective for human malignant cell lines than for nonmalignant fibroblasts.
AB - A library of 5-methylindolo[3,2-c]quinolones (IQc) with various substitution patterns of alkyldiamine side chains were evaluated for G-quadruplex (G4) binding mode and efficiency. Fluorescence resonance energy transfer melting assays showed that IQcs with a positive charge in the heteroaromatic nucleus and two weakly basic side chains are potent and selective human telomeric (HT) and gene promoter G4 stabilizers. Spectroscopic studies with HT G4 as a model showed that an IQc stabilizing complex involves the binding of two IQc molecules (2,9-bis{[3-(diethylamino)propyl]amino}-5-methyl-11H-indolo[3,2-c]quinolin-5-ium chloride, 3 d) per G4 unit, in two non-independent but equivalent binding sites. Molecular dynamics studies suggest that end-stacking of 3 d induces a conformational rearrangement in the G4 structure, driving the binding of a second 3 d ligand to a G4 groove. Modeling studies also suggest that 3 d, with two three-carbon side chains, has the appropriate geometry to participate in direct or water-mediated hydrogen bonding to the phosphate backbone and/or G4 loops, assisted by the terminal nitrogen atoms of the side chains. Additionally, antiproliferative studies showed that IQc compounds 2 d (2-{[3-(diethylamino)propyl]amino}-5-methyl-11H-indolo[3,2-c]quinolin-5-ium chloride) and 3 d are 7- to 12-fold more selective for human malignant cell lines than for nonmalignant fibroblasts.
KW - G-quadruplexes
KW - antitumor agents
KW - cancer
KW - indolo[3,2-c]quinolones
KW - molecular dynamics
UR - http://www.scopus.com/inward/record.url?scp=84928492026&partnerID=8YFLogxK
U2 - 10.1002/cmdc.201500067
DO - 10.1002/cmdc.201500067
M3 - Article
C2 - 25820698
AN - SCOPUS:84928492026
SN - 1860-7179
VL - 10
SP - 836
EP - 849
JO - ChemMedChem
JF - ChemMedChem
IS - 5
ER -