The influence of 2,4,6-tribromophenyl isocyanate on the cellular and nuclear uptake of the SV 40 T antigen nuclear localization sequence.

The objective of the present study was to evaluate the influence of 2,4,6-tribromophenyl isocyanate (TBPI) on the cellular and nuclear uptake of the fluorescein isothiocyanate (FITC) labeled SV 40 T antigen nuclear localization sequence in human LN18 and U373 glioma cells. Therefore, the FITC-labeled nuclear localization sequence (NLS) of the SV 40 T antigen was coupled to 2,4,6-TBPI. This TBPI-NLS conjugate was taken up by the cell nuclei of more than 90% of human malignant glioma cells. The nuclearly stained cells showed clear signs of cell death. However only up to 10% of the cells were stained after incubation with the TBPI-lacking NLS of the SV 40 T antigen together with free, unbound TBPI. These cells stayed alive. TBPI, when bound to small peptides, may be an important component for future drugs against gliomas.