Figure 5

Sigma-2 receptor ligand-mediated cell death is dependent on lysosomal accumulation and membrane permeabilization. (A) Accumulation of sigma-2 receptor ligands SW120 and PB385 in Bxpc3 cells following inhibition of lysosomal pH gradient with the V-ATPase inhibitor concanamycin A (CMA) (10 nM) detected by flow cytometry. (B) Cell viability following 24 treatment with sigma-2 receptor ligands SW43 and PB282 or lysosomal detergent hydroxychlorquine (HCQ) in the presence of CMA (10 nM). Data represents percent viability compared to DMSO treated cells, n = 3, p < 0.05 (C) Cleavage of fluorescent peptidase substrate Z-RR-AMC following one hour treatment with SW43 (30 μM), PB282 (30 μM), or HCQ (60 μM), in the presence of CMA (10 nM) or peptidase inhibitors CA-074-Me (10 μM) and pepstatin A (100 μM). Data is relative to DMSO treated cells and is representative of experiments performed in triplicate. (D) Cell viability following 24 hour treatment with SW43, PB282, or HCQ in the presence of CA-074-Me or pepstatin A. Data represents percent viability compared to DMSO treated cells, n = 3.