The link between autophagy and MPR expression in tumor cells. A, formation of LC3 punctae in tumor cells by overnight treatment with different drugs. Staining with LC3 specific antibody (red). Bar, 25 μm. B–D, MPR upregulation in B16F10 cell induced by paclitaxel (TAX; B) or in U266 cells induced by doxorubicin (DOX; C and D) was abrogated by inhibitor of autophagy 3MA. Staining of cells was evaluated by flow cytometry (B and C) and by confocal microscopy (D). A–D, each experiment was conducted at least 3 times. E, autophagy inhibitor 3MA abrogated combined cytotoxic effect of paclitaxel (12.5 ng/ mL, overnight treatment) and CTLs (activated Pmel T cells) against B16F10 tumor cells. Standard 51Cr-release assay was conducted in duplicates. Results of 2 experiments are shown (mean ± SD). Unt, untreated cells.