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. 2011 Dec 1;25(23):2465–2479. doi: 10.1101/gad.180331.111

Figure 3.

Figure 3.

Macrophage-supplied cathepsins protect tumor cells from cell death. (A) Schematic of coculture assay. (B) Percentage of DAPI+ (dead) tumor cells in mono- or coculture of the TS1 cell line with wild-type (WT) BMDMs 48 h after Taxol (50 nM) or DMSO treatment. Addition of the cathepsin inhibitor JPM (10 μM) abrogated the protective effect of BMDMs following Taxol treatment. (C) BMDMs also protected from Taxol-induced cell death in additional PyMT-derived tumor cell lines, TS2, Met-1, and AT-3, with experimental conditions as in B. (D) Percentage of TS1 tumor cell death in monoculture and in cocultures with wild-type or cathepsin B-, cathepsin S-, cathepsin C-, or cathepsin L-null BMDMs 48 h after treatment. Deletion of cathepsin B or cathepsin S significantly reduced macrophage-conferred protection. (E) Macrophage-conferred protection is largely contact-independent. Cell death in TS1 tumor cells cultured alone or in the presence of wild-type BMDM-CM or CAF-CM 48 h after treatment with Taxol or DMSO control. Addition of JPM (10 μM) to the CM abrogated the BMDM-conferred protection. For all graphs, data are from three independent experiments, each done in triplicate. (*) P < 0.05; (**) P < 0.01; (***) P < 0.001; (ns) not significant.