Cellular uptake of hematoporphyrin derivative in KK-47 bladder cancer cells

The fluorescence emission spectra and degree of fluorescence polarization of hematoporphyrin derivative (HpD) have been investigated using HpD-containing KK-47 cells, PBS and cetyl trimethyl ammonium chloride (CTAC) micellar solutions. The fluorescence emission bands in the HpD-containing cell suspension were red-shifted and broadened as compared to those in the PBS solution. The degree of the polarization in the PBS and CTAC micellar solutions did not change with increasing incubation time, but in the cell suspension it increased temporarily and then decreased 4 h after incubation. These results suggest that HpD monomers and dimers may bind weakly to the outer cell membrane, and then slowly distribute throughout the intracellular loci in strong-binding form. In addition, the cellular uptake and/or binding loci of HpD were considered to be the mitochondria and nuclear membrane by subcellular fractionation and fluorescence microscopic studies.