Regulation of the intra-mitochondrial content of ALA-mediated PpIX by Ko143, a specific inhibitor of ABCG2.

U937 cells and A549 cells were incubated for 3 h with 1 mM ALA in complete medium in the presence or absence of 1 µM Ko143. After incubation, cells were washed with ALA-free medium and mitochondrial and cytosolic fractions were isolated as described in Materials and Methods. The fluorescence spectrum of each fraction was analyzed by a fluorophotometer. A representative histogram of three independent experiments is shown. The levels of PpIX were shown by black line (No treatment), red line (ALA without Ko143), green line (ALA with Ko143), respectively.