abstract
Cancer is a leading cause of death, so continuous efforts into cancer therapy are imperative. In tumor cells, telomerase and oncogene activity are key points for uncontrolled cell growth. Targeting these processes with ligands that inhibit telomerase and/or reduce oncogene expression has been identified as a promising cancer therapy. This study evaluated the selectivity and affinity of the silver(II) complex of 5,10,15,20-tetrakis(N-methyl-4-pyridinium)porphyrin (AgTMPyP) to stabilize DNA sequences capable of forming G4 structures mimicking the telomeric and oncogene regions, using spectroscopic, biochemical methods and in vitro assays. The tetracationic silver complex was compared with the free base, H2TMPyP, and the zinc(II) complex, ZnTMPyP. The results obtained from UV-Vis and fluorescence methods pointed to a great affinity and good selectivity of AgTMPyP to G4 structures, especially for the oncogene MYC. In general, an increase in the ability of the studied ligands for O-1(2) generation when interacting with oncogenic and telomeric G4 sequences was found. The results of the PCR stop assays proved that AgTMPyP has the ability to inhibit Taq polymerase. Additionally, in vitro assays demonstrated that the silver(II) complex exhibits low cytotoxicity against HaCaT- an immortalized, non-tumorigenic, skin keratinocytes cell line-and, although nonexclusive, AgTMPyP shows nuclear co-localization.
keywords
TELOMERASE ACTIVITY; PHOTODYNAMIC INACTIVATION; STAPHYLOCOCCUS-AUREUS; KRAS PROTOONCOGENE; GRAPHENE OXIDE; ALAMAR BLUE; HUMAN SKIN; DNA; PROMOTER; MYC
subject category
Biochemistry & Molecular Biology; Chemistry
authors
Moura, NMM; Guedes, S; Salvador, D; Oliveira, H; Neves, MGPMS; Ramos, CIV
our authors
Diana Serenela Andrade Salvador
PhD Student
Helena Oliveira
Post-Doc Fellowshipacknowledgements
This research work has received financial support from PT national funds (FCT/MCTES, Fundacao para a Ciencia e a Tecnologia and Ministerio da Ciencia, Tecnologia e Ensino Superior) through the projects LAQV-REQUIMTE (LA/P/0008/2020 DOI 10.54499/LA/P/0008/2020, UIDP/50006/2020 DOI 10.54499/UIDP/50006/2020, and UIDB/50006/2020 DOI 10.54499/UIDB/50006/2020) and CESAM (UID/AMB/50017/2019 and UIDB/50017/2020 + UIDP/50017/2020) research units through national funds and, where applicable, was co-financed by the FEDER, within the PT2020 Partnership Agreement, and to the Portuguese NMR Network. NMM Moura and CIV Ramos thank the FCT for funding through the program DL 57/2016 Norma transitoria (CDL-CTTRI- 048-88-ARH/2018 and CDL-CTTRI-047-88-ARH/2018). H. Oliveira thanks the FCT for the research contract under the Scientific Employment Stimulus (CEECIND/04050/2017), and D. Salvador thanks the FCT for her PhD grant (2022.11049.BD).