Cadmium Activates Reactive Oxygen Species-dependent AKT/mT OR and Mitochondrial Apoptotic Pathways in Neuronal Cells

Objective To examine the role of Cd-induced reactive oxygen species（ROS） generation in the apoptosis of neuronal cells. Methods Neuronal cells（primary rat cerebral cortical neurons and PC12 cells） were incubated with or without Cd post-pretreatment with rapamycin（Rap） or N-acetyl-L-cysteine（NAC）. Cell viability was determined by MTT assay, apoptosis was examined using flow cytometry and fluorescence microscopy, and the activation of phosphoinositide 3’-kinase/protein kinase B（Akt）/mammalian target of rapamycin（m TOR） and mitochondrial apoptotic pathways were measured by western blotting or immunofluorescence assays. Results Cd-induced activation of Akt/m TOR signaling, including Akt, m TOR, p70 S6 kinase（p70 S6K）, and eukaryotic initiation factor 4E binding protein 1（4E-BP1）. Rap, an m TOR inhibitor and NAC, a ROS scavenger, blocked Cd-induced activation of Akt/m TOR signaling and apoptosis of neuronal cells. Furthermore, NAC blocked the decrease of B-cell lymphoma 2/Bcl-2 associated X protein（Bcl-2/Bax） ratio, release of cytochrome c, cleavage of caspase-3 and poly（ADP-ribose） polymerase（PARP）, and nuclear translocation of apoptosis-inducing factor（AIF） and endonuclease G（Endo G）. Conclusion Cd-induced ROS generation activates Akt/m TOR and mitochondrial pathways, leading to apoptosis of neuronal cells. Our findings suggest that m TOR inhibitors or antioxidants have potential for preventing Cd-induced neurodegenerative diseases.

Amyloid precursor protein regulates 5-fluorouracil resistance in human hepatocellular carcinoma cells by inhibiting the mitochondrial apoptotic pathway

Hepatocellular carcinoma(HCC)is a malignant tumor with high morbidity and mortality globally.It accounts for the majority of primary liver cancer cases.Amyloid precursor protein(APP),a cell membrane protein,plays a vital role in the pathogenesis of Alzheimer’s disease,and has been found to be implicated in tumor growth and metastasis.Therefore,to understand the relationship between APP and 5-fluorouracil(5-FU)resistance in liver cancer,Cell Counting Kit-8,apoptosis and cell cycle assays,western blotting,and reverse transcription-quantitative polymerase chain reaction(q PCR)analysis were performed.The results demonstrated that APP expression in Bel7402-5-FU cells was significantly up-regulated,as compared with that in Bel7402 cells.Through successful construction of APP-silenced(si APP)and overexpressed(OE)Bel7402 cell lines,data revealed that the Bel7402-APP751-OE cell line was insensitive,while the Bel7402-si APP cell line was sensitive to 5-FU in comparison to the matched control group.Furthermore,APP overexpression decreased,while APP silencing increased 5-FU-induced apoptosis in Bel7402 cells.Mechanistically,APP overexpression and silencing can regulate the mitochondrial apoptotic pathway and the expression of apoptotic suppressor genes(B-cell lymphoma-2(Bcl-2)and B-cell lymphoma-extra large(Bcl-xl)).Taken together,these results preliminarily revealed that APP overexpression contributes to the resistance of liver cancer cells to 5-FU,providing a new perspective for drug resistance.

Thermotherapy enhances oxaliplatin-induced cytotoxicity in human colon carcinoma cells

AIM： To observe the synergistic effects of hyperthermia in oxaliplatin-induced cytotoxicity in human colon adenocarcinoma Lovo cells.