Synthesis and cellular studies of a carboranylchlorin for the PDT and BNCT of tumors

The syntheses of closo- and nido-carboranylchlorins 4 and 5 from a known carboranylporphyrin are described. Water-soluble nido-carboranylporphyrin 5 was found to have very low dark cytotoxicity (IC50 > 500 μM using a MTT-based assay) but to be toxic in the presence of red light (IC50 = 80 μM at 0.55 J/cm2 light dose). Under the same experimental conditions, carboranylchlorin 5 was taken up by human glioma T98G cells to a significantly higher extent than chlorin e6, a chlorophyll degradation product. The preferred sites of subcellular localization of carboranylchlorin 5 were found to be the cell lysosomes. Our results suggest that carboranylchlorin 5 is a promising new dual sensitizer for the PDT and BNCT treatment of tumors.

The syntheses of a water-soluble carboranylchlorin are described. This compound has low dark cytotoxicity but is toxic in the presence of light. The new carboranylchlorin is efficiently taken up by T98G cells and it localizes intracellularly preferentially within the lysosomes.Figure optionsDownload as PowerPoint slide