The Interactions of H2TMPyP, Analogues and Its Metal Complexes with DNA G-Quadruplexes-An Overview


The evidence that telomerase is overexpressed in almost 90% of human cancers justifies the proposal of this enzyme as a potential target for anticancer drug design. The inhibition of telomerase by quadruplex stabilizing ligands is being considered a useful approach in anticancer drug design proposals. Several aromatic ligands, including porphyrins, were exploited for telomerase inhibition by adduct formation with G-Quadruplex (GQ). 5,10,15,20-Tetrakis(N-methyl-4-pyridinium)porphyrin (H2TMPyP) is one of the most studied porphyrins in this field, and although reported as presenting high affinity to GQ, its poor selectivity for GQ over duplex structures is recognized. To increase the desired selectivity, porphyrin modifications either at the peripheral positions or at the inner core through the coordination with different metals have been handled. Herein, studies involving the interactions of TMPyP and analogs with different DNA sequences able to form GQ and duplex structures using different experimental conditions and approaches are reviewed. Some considerations concerning the structural diversity and recognition modes of G-quadruplexes will be presented first to facilitate the comprehension of the studies reviewed. Additionally, considering the diversity of experimental conditions reported, we decided to complement this review with a screening where the behavior of H2TMPyP and of some of the reviewed metal complexes were evaluated under the same experimental conditions and using the same DNA sequences. In this comparison under unified conditions, we also evaluated, for the first time, the behavior of the Ag-II complex of H2TMPyP. In general, all derivatives showed good affinity for GQ DNA structures with binding constants in the range of 10(6)-10(7) M-1 and ligand-GQ stoichiometric ratios of 3:1 and 4:1. A promising pattern of selectivity was also identified for the new Ag-II derivative.



subject category

Biochemistry & Molecular Biology


Ramos, CIV; Monteiro, AR; Moura, NMM; Faustino, MAF; Trindade, T; Neves, MGPMS

our authors


This research was funded by the University of Aveiro and the Fundacao para a Ciencia e a Tecnologia (FCT). Financial support was provided by LAQV-REQUIMTE (Ref.UIDB/50006/2020) and CICECO-Aveiro Institute of Materials (Ref. UID/CTM/50011/2020) through national funds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement. The authors also acknowledge the Portuguese NMR and Mass Networks. Catarina IV Ramos (REF.-047-88-ARH/2018) and Nuno MM Moura (REF.-048-88-ARH/2018) acknowledge their research contracts which are funded by national funds (OE), through FCT-Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in numbers 4, 5 and 6 of the article 23, of the Law Decree 57/2016, of August 29, changed by Law 57/2017, of July 19. Ana R. Monteiro thanks FCT for her Ph.D. grant SFRH/BD/137356/2018.

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