Quaternized styryl-azinium fluorophores as cellular RNA-binders

• Published in: Photochemical & photobiological sciences Vol. 19; no. 3; pp. 362 - 37
• Main Authors: Botti, Valentina, Urbanelli, Lorena, Sagini, Krizia, Tarpani, Luigi, Cesaretti, Alessio, Fortuna, Cosimo G, Elisei, Fausto
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2020; Royal Society of Chemistry
• Subjects: Absorption spectroscopy; Binders; Biochemistry; Biomaterials; Chemical compounds; Chemistry; Confocal microscopy; Deoxyribonucleic acid; DNA; Fluorescence; Fluorescent Dyes - chemistry; Fluorescent Dyes - metabolism; Fluorophores; Humans; Iodides; MCF-7 Cells; Microscopy, Confocal; Molecular Structure; Optical Imaging; Photochemical Processes; Physical Chemistry; Plant Sciences; Pyrazines - chemistry; Pyrazines - metabolism; Ribonucleases - chemistry; Ribonucleases - metabolism; Ribonucleic acid; RNA; RNA - chemistry; RNA - metabolism; Spectrophotometry; Styrenes - chemistry; Styrenes - metabolism; tRNA; Tumor Cells, Cultured
• ISSN: 1474-905X; 1474-9092
• DOI: 10.1039/c9pp00465c

The capability of three quaternized styryl-azinium iodides to bind cellular RNA has been tested by means of Fluorescence Confocal Microscopy imaging of stained MCF-7 cells treated with RNase. Their association constants have been estimated through spectrophotometric and fluorimetric titrations with tRNA and compared to their affinity toward DNA. Transient absorption spectroscopy with femtosecond resolution confirmed the binding of the investigated compounds with tRNA and shed new light on the excited state dynamics of their complexes, by revealing a significant lengthening of the lifetime of S 1 upon complexation, which parallels the fluorescence quantum yield enhancement. Small dyes' micromolar cytotoxicity, efficient dsRNA-binding and highly selective nucleolar localisation marked by strong fluorescence enhancement: potential theragnostics applications.