Fig. 4

Mitochondrial fragmentation-mediated mROS induces HtrA2/Omi liberation. a, b Immunofluorescence measurements of HtrA2/Omi in response to erlotinib treatment. Mdivi-1 was used to inhibit mitochondrial fragmentation. c–f Cytoplasmic HtrA2/Omi (cyto-HrA2/Omi), cytoplasmic cyt c (cyto-cyt c), mitochondrial HtrA2/Omi (mito-HtrA2/Omi) and mitochondrial cyt c (mito-cyt c) were determined using western blotting analysis. g, h Cardiolipin oxidation was observed using an NAO probe. In response to cardiolipin oxidation, NAO could not bind to oxidized cardiolipin, and thus the green fluorescence was reduced. Accordingly, the relative fluorescence intensity was recorded to quantify cardiolipin oxidation. MitoQ was added to the medium of PANC-1 cells to neutralize the mROS that were produced by mitochondrial fragmentation. i mPTP opening was determined using tetramethylrhodamine ethyl ester. The relative mPTP opening rate was quantified as a ratio to that of control group. *p < 0.05