PL3 CendR peptide shows specific uptake in cultured Y79 retinoblastoma cells with nucleolar accumulation

Retinoblastoma is the most common pediatric intraocular malignant tumor affecting 1:15 000–1:20 000 live births. Even though the survival rate in developed countries is over 90 %, more efficient treatment options are needed for better vision salvage and reduction of the adverse effects. Therefore, we investigated fluorescein-labeled PL3 peptide targeting properties towards the Y79 retinoblastoma cell line in vitro. Through the application of cellular imaging and flow cytometry techniques, the PL3 peptide exhibited a rapid and specific internalization within Y79 cells, with subsequent translocation to the cell nuclei, showcasing notable accumulation in the nucleoli. This phenomenon was not present in other investigated cell lines and was not observable with similarly charged and length control peptide. However, the exact mechanism behind this Y79 cell line-specific nuclear and nucleolar targeting pattern remains elusive. In the future, this targeting process could facilitate specific treatment modalities of retinoblastoma with PL3 peptide-coupled drug delivery technologies.