Fig. 5: Cytosolic cathepsin B induced an increase in MOMP. | Cell Death & Disease

Fig. 5: Cytosolic cathepsin B induced an increase in MOMP.

From: Tubeimoside I-induced lung cancer cell death and the underlying crosstalk between lysosomes and mitochondria

Fig. 5

a Tub induced upregulation of conformation-changed Bax and downregulation of cytochrome C in mitochondria, and an increase in cytochrome C in the cytoplasm. The mitochondrial and cytosolic fractions were extracted and subjected to western blot analysis. b Tub induced a significant increase in MOMP. NCI-H1975 cells were treated with Tub (20 μM) or CCCP (10 μM) for 24 h; CCCP was used as a positive control, as CCCP can induce the depolarization of mitochondria. Mitochondrial membrane potential (MMP) was measured with the JC-1 kit. c E64d, a cathepsin B inhibitor, significantly reversed the increase in MOMP induced by Tub. NCI-H1975 cells were treated with Tub (20 μM), E64d or both Tub and E64d for 24 h. The mitochondrial membrane potential (MMP) was measured with the JC-1 kit. d Treatment with E64d (20 μM) or CA (CA-074 methyl ester, 10 μM) (both inhibitors of cathepsin B) for 24 h resulted in a significant reduction in cytosolic cytochrome C in Tub-treated NCI-H1299 cells. **p < 0.01, ***p < 0.001 vs. the indicated groups.

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