Selective binding of a bioactive porphyrin-based photosensitizer to the G-quadruplex from the KRAS oncogene promoter.
Int J Biol Macromol 2019;
145:244-251. [PMID:
31870869 DOI:
10.1016/j.ijbiomac.2019.12.152]
[Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/07/2019] [Accepted: 12/17/2019] [Indexed: 01/24/2023]
Abstract
BACKGROUND
The G-quadruplex-forming sequence within the KRAS proto-oncogene P1 promoter is a promising target for anticancer therapy. Porphyrin derivatives are among the most rewarding G-quadruplex binders. They can also behave as photosensitizers.
METHODS
Three water-soluble, positively charged porphyrin-like compounds were synthesized and tested for their interaction with the KRAS G-quadruplex by circular dichroism, fluorescence, and molecular docking calculations. For a comparison of ligands binding affinity and selectivity, TMPyP4 was taken as a reference.
RESULTS
One out of the three tested compounds proved biological activity and selectivity for G-quadruplex over duplex DNA. It also showed to discriminate between different G-quadruplex topologies, with a preference for the parallel over antiparallel conformation. Molecular docking studies suggested a preferential binding to the 3'-end of the KRAS G-quadruplex driven through π-π stacking interactions. Biological assays also revealed a good photodynamic-induced cytotoxicity on HeLa cells.
CONCLUSIONS
The reported results show that these porphyrin-like compounds could actually give the basis for the development of G-quadruplex ligands with effective photodynamic-induced cytotoxicity on cancer cells.
GENERAL SIGNIFICANCE
The possibility of obtaining photosensitizers with improved physico-chemical features and able to selectively target G-quadruplexes is a very interesting perspective to develop new therapeutic agents.
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