Highly DNA‐Photoreactive Ruthenium 1, 4, 5, 8‐Tetraazaphenanthrene Complex Conjugated to the TAT Peptide: Efficient Vectorization inside HeLa Cells without Phototoxicity – The Importance of Cellular Distribution. Issue 18 (27th April 2016) - Marcélis, Lionel
Abstract : The photoreactive [Ru(TAP)2 (phen)] 2+ (TAP = 1, 4, 5, 8‐tetraazaphenanthrene; phen = 1, 10‐phenanthroline) complex tethered to the cell‐penetrating peptide (CPP) TAT was studied in vitro and in cellulo. The tethering of the complex does not affect its behavior under blue‐light irradiation in the presence of guanine‐containing oligodeoxyribonucleotides (ODNG ). Thus, the luminescence is quenched in the presence of ODNG, and gel electrophoresis experiments showed the appearance of products corresponding to the irreversible attachment of the conjugate to ODNG upon illumination. The cellular uptake of the conjugate was examined by flow cytometry, inductively coupled plasma mass spectrometry (ICP‐MS), and confocal imaging microscopy. These experiments showed that the [Ru(TAP)2 (phen‐TAT)] conjugate is readily taken up by HeLa cells and, despite these favorable factors, the cellular survival was 100 %, as measured by a 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide (MTT) assay. A possible origin of the inactivity of [Ru(TAP)2 (phen‐TAT)] under irradiation is proposed on the basis of the fluorescence‐activated cell sorting (FACS), ICP‐MS, and confocal microscopy results. Abstract : Photoreactive [Ru(TAP)2 (phen)] 2+ (TAP = 1, 4, 5, 8‐tetraazaphenanthrene; phen = 1, 10‐phenanthroline) is tethered to the cell‐penetrating peptide TAT. Despite its ability to form stable photoadducts with DNA and efficient transportation into the cells, no photocytotoxicity was observed. A possible origin of the inactivity of the TAT‐conjugated [Ru(TAP)2 (phen)] 2+ under illumination is proposed.