Lipofuscin labeling through biorthogonal strain-promoted azide-alkyne cycloaddition for the detection of senescent cells

[EN] A new method for senescent cell detection is described, which is based on lipofuscin labeling with a fluorescent reporter through a biorthogonal strain-promoted azide-alkyne cycloaddition. The sensing protocol involves a first step where the interaction of lipofuscin with a Sudan Black B derivative containing an azide moiety (SBB-N3 ) is carried out. In the final step, the azide moiety reacts with a fluorophore containing a cyclooctene ring (BODIPY). The efficacy of this two-step protocol is assessed in senescent melanoma SK-MEL-103 cells, senescent triple-negative breast cancer MDA-MB-231 cells and senescent WI-38 fibroblasts. In all cases, a clear fluorescence pattern was observed in senescent cells, compared to proliferative cells, only when the SBB-N3 -BODIPY probe was formed. Our results provide an alternative tool for the detection of senescent cells, based on an in situ bio-orthogonal reaction for lipofuscin labeling
RM laboratory members are grateful for financial support from the FEDER foundation of European Union (IDIFEDER/2021/044), the Spanish Government (projects RTI2018-100910-B-C41 and RTI2018-101599-B-C22) and the Generalitat Valenciana (project PROMETEO 2018/024). BL-T and AG-F acknowledge their current Margarita Salas postdoctoral fellowship from UPV-MIU and 'Next Generation EU' program. JF-B is grateful for his Sara Borrell postdoctoral fellowship (CD19/00038).