FIGURE 4.

Colocalization of DOX with LAMP2-stained lysosomes is Pgp-dependent. A–D, in KB31 (−Pgp) cells, colocalization of DOX with the nuclear marker DAPI was demonstrated under control conditions. E–L, the Pgp inhibitors Val (E–H) and Ela (I–L) did not affect DOX distribution relative to the control in KB31 (−Pgp) cells. M–P, incubation of KBV1 (+Pgp) cells expressing functional Pgp with DOX leads to colocalization of this drug with the marker for lysosomes, LAMP2 (P, arrows), whereas the Pgp inhibitors Val (Q–T) and Ela (U–X) result in DOX redistribution to the nucleus. The results in A–X are typical from three experiments. Scale bars = 50 μm.