Quinoline- and benzoselenazole-derived unsymmetrical squaraine cyanine dyes: design, synthesis, photophysicochemical features and light-triggerable antiproliferative effects against breast cancer cell lines

• Published in: Materials Vol. 13; no. 11; p. 2646
• Main Authors: Lima, Eurico, Boto, Renato E., Ferreira, Diana, Fernandes, José R., Almeida, Paulo, Ferreira, Luis F. V., Souto, Eliana B., Silva, Amélia M., Reis, Lucinda V.
• Format: Journal Article
• Language: English
• Published: Basel MDPI Publishing 10.06.2020; MDPI AG; MDPI
• Subjects: Absorption; Antiproliferatives; Aqueous solutions; benzoselenazole; Breast cancer; Cancer therapies; Cell death; Cyanine dyes; Cytotoxicity; Dyes; Endangered & extinct species; Infrared spectra; light-stability; Near infrared radiation; NMR; Nuclear magnetic resonance; Photodynamic therapy; phototherapeutic effects; Quinoline; Science & Technology; Singlet oxygen; Solvents; Stability; Synthesis; Tumors; unsymmetrical squaraine dyes; United States > US; Portugal; Germany
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma13112646

Photodynamic therapy is an innovative treatment approach broadly directed towards oncological diseases. Its applicability and efficiency are closely related to the interaction of three main components, namely a photosensitizer, light and molecular triplet oxygen, which should drive cell death. Recently, several studies have demonstrated that squaraine cyanine dyes have a set of photophysical and photochemical properties that have made of these compounds’ potential photosensitizers for this therapeutic modality. In the present research work, we describe the synthesis and characterization of four quinoline- and benzoselenazole-derived unsymmetrical squaraine cyanine dyes. Except for the precursor of aminosquaraine dyes, i.e., O-methylated derivative, all dyes were evaluated for their behavior and absorption capacity in different organic and aqueous solvents, their ability to form singlet oxygen, their light-stability, and in vitro phototherapeutic effects against two human breast cancer cell cultures (BT-474 and MCF-7). Regardless of the nature of the used solvents, the synthesized dyes showed intense absorption in the red and near-infrared spectral regions, despite the formation of aggregates in aqueous media. Dyes showed high light-stability against light exposure. Despite the low ability to produce singlet oxygen, aminosquaraine dyes demonstrated worthy in vitro phototherapeutic activity. This research was funded by the European Investment Funds by FEDER/COMPETE/POCI under projects POCI-01-0145-FEDER-006958 (CITAB) and POCI-01-0145-FEDER-007491 (CICS-UBI) and Funds by FCT—Portuguese Foundation for Science and technology, under the projects UIDB/ 04033/2020 (CITAB) and UIDB/ 00616/2020 (CQ-VR). This work was also supported by funds from the Health Sciences Research Center (CICS-UBI) through National Funds by FCT—Foundation for Science and Technology (UID/Multi/00709/2019).The research at iBB was supported by Project UID/NAN/50024/2019 and M-ERA-NET/0002/2015 from FCT. E.L. was supported by the FCT PhD grant SFRH/BD/147645/2019.