Effects of a halogenated G-quadruplex ligand from the pyridine dicarboxamide series on the terminal sequence of XpYp telomere in HT1080 cells

► Halogenated derivatives of 360A G-quadruplex ligand have been synthesized. ► Halogenated 360A derivatives display potent affinity and selectivity for telomeric G-quadruplex over duplex DNA. ► 360A-Br induces delayed growth inhibition in HT1080 tumor cell line. ► 360A-Br triggers mild modifications of the telomeric C-strand resection using C-STELA assay.