Bid mediates lysosomal membrane permeabilization and the consequent mitochondrial outer membrane permeabilization in RH-35 hepatoma cells

We reported previously that chymotrypsin B is cached in the lysosomes of rat hepatocytes and mediates apoptosis induced by TNF-alpha (1) and H2O2. However, the mechanism

Salvianolic acid B protects hepatocytes from H2O2 injury by stabilizing the lysosomal membrane

AIM To investigate the capability of salvianolic acid B(Sal B) to protect hepatocytes from hydrogen peroxide(H_2O_2)/carbon tetrachloride(CCl_4)-induced lysosomal membrane permeabilization. METHODS Cell Counting Kit-8 assay was used to measure cell viability. Apoptosis and death were assayed through flow cytometry. Brd U incorporation was used to detect cell proliferation. Serum alanine aminotransferase activity and liver malondialdehyde(MDA) content were measured. Liver histopathological changes were evaluated using hematoxylin-eosin staining. Lysosomal membrane permeability was detected with Lyso Tracker Green-labeled probes and acridine orange staining. The levels of protein carbonyl content(PCC), cathepsins(Cat)B/D, and lysosome-associated membrane protein 1(LAMP1) were evaluated through western blotting. Cytosol Cat B activity analysis was performed with chemiluminescence detection. The m RNA level ofLAMP1 was evaluated through quantitative real-time polymerase chain reaction. RESULTS Results indicated that H_2O_2 induced cell injury/death. Sal B attenuated H_2O_2-induced cell apoptosis and death, restored the inhibition of proliferation, decreased the amount of PCC, and stabilized the lysosome membrane by increasing the LAMP1 protein level and antagonizing Cat B/D leakage into the cytosol. CCl_4 also triggered hepatocyte death. Furthermore, Sal B effectively rescued hepatocytes by increasing LAMP1 expression and by reducing lysosomal enzyme translocation to the cytosol.CONCLUSION Sal B protected mouse embryonic hepatocytes from H_2O_2/CCl_4-induced injury/death by stabilizing the lysosomal membrane.

MiR-183-5p-PNPT1 Axis Enhances Cisplatin-induced Apoptosis in Bladder Cancer Cells

Objective:It has been reported that intrinsic apoptosis is associated with the progression of bladder cancer(BC).Recent evidence suggests that polyribonucleotide nucleotidyltransferase 1(PNPT1)is a pivotal mediator involved in RNA decay and cell apoptosis.However,the regulation and roles of PNPT1 in bladder cancer remain largely unclear.Methods:The upstream miRNA regulators were predicted by in silico analysis.The expression levels of PNPT1 were evaluated by real-time PCR,Western blotting,and immunohistochemistry(IHC),while miR-183-5p levels were evaluated by qPCR in BC cell lines and tissues.In vitro and in vivo assays were performed to investigate the function of miR-183-5p and PNPT1 in apoptotic RNA decay and the tumorigenic capability of bladder cancer cells.Results:PNPT1 expression was decreased in BC tissues and cell lines.Overexpression of PNPT1 significantly promoted cisplatin-induced intrinsic apoptosis of BC cells,whereas depletion of PNPT1 potently alleviated these effects.Moreover,oncogenic miR183-5p directly targeted the 3′UTR of PNPT1 and reversed the tumor suppressive role of PNPT1.Intriguingly,miR-183-5p modulated not only PNPT1 but also Bcl2 modifying factor(BMF)to inhibit the mitochondrial outer membrane permeabilization(MOMP)in BC cells.Conclusion:Our results provide new insight into the mechanisms underlying intrinsic apoptosis in BC,suggesting that the miR-183-5p-PNPT1 regulatory axis regulates the apoptosis of BC cells and might represent a potential therapeutic avenue for the treatment of BC.

Cholesterol-associated lysosomal disorder triggers cell death of hematological malignancy:Dynamic analysis on cytotoxic effects of LW-218

The integrity of lysosomes is of vital importance to survival of tumor cells.We demonstrated that LW-218,a synthetic flavonoid,induced rapid lysosomal enlargement accompanied with lysosomal membrane permeabilization in hematological malignancy.LW-218-induced lysosomal damage and lysosome-dependent cell death were mediated by cathepsin D,as the lysosomal damage and cell apoptosis could be suppressed by depletion of cathepsin D or lysosome alkalization agents,which can alter the activity of cathepsins.Lysophagy,was initiated for cell self-rescue after LW-218 treatment and correlated with calcium release and nuclei translocation of transcription factor EB.LW-218 treatment enhanced the expression of autophagy-related genes which could be inhibited by intracellular calcium chelator.Sustained exposure to LW-218 exhausted the lysosomal capacity so as to repress the normal autophagy.LW-218-induced enlargement and damage of lysosomes were triggered by abnormal cholesterol deposition on lysosome membrane which caused by interaction between LW-218 and NPC intracellular cholesterol transporter 1.Moreover,LW-218 inhibited the leukemia cell growth in vivo.Thus,the necessary impact of integral lysosomal function in cell rescue and death were illustrated.