Effects of blocking DNA-PKcs on autophagy protein expression and proliferation in esophageal squamous cell carcinoma cell line EC109 after irradiation / 重庆医学

Objective To study the effect of DNA-PKcs blocking on the expression of autophagic proteins,and proliferation of esophageal squamous cell carcinoma cells(EC109)after irradiation(X-Ray).Methods NU7441 was used to inhibit DNA-PKcs and X-Ray radiation treatment were used to treat EC109 cells.Th experiment was divided into 4 groups,including control group, NU7441 group,X-Ray group,X-Ray+ NU7441 group.The expressions of autophagy protein Beclin-1 and LC3B were detected by Western blot.Apoptosis was detected by flow cytometry.MTT assay was used to detect cell proliferation.Results The expression of p-DNA-PKcs in EC109 cells was decreased after NU7441 treatment and increased after X-ray irradiation.Compared with untreat-ed cells(control group),the expressions of both Beclin-1 and LC3B in X-Ray+NU7441 group were increased.Compared with the X-Ray group,the expression of Beclin-1 in the X-Ray+NU7441 group was increased.Compared with the control group,the apoptotic rate of EC109 cells in the X-Ray group and X-Ray+NU7441 group was significantly increased,the difference was statistically significant(P<0.05).Compared with the X-Ray group the apoptosis rate in the X-Ray-NU7441 group was significantly increased.The MTT results showed that compared with the control group,the proliferation in the X-Ray group and X-Ray+NU7441 group was significantly inhibited, the difference was statistically significant(P<0.05).Conclusion NU7441 inhibits the expression of DNA-PKcs protein in EC109 cells, which could promote the expressions of autophagy protein Beclin-1 and LC3B,promotes apoptosis and inhibits cell proliferation.

Trametenolic acid B induces the programmed death of human gastric cancer HGC-27 cells / 中成药

AIM To study the programmed death effect of trametenolic acid B (TAB) against human gastric cancer HGC-27 cells.METHODS The proliferation of cells was examined by MTT assay;cell apoptosis rate and cell cycle were detected by flow cytometry;cell autophagy was observed by acridine orange staining and transmission electron microscope;expressions of autophagy-related proteins were detected by Western blot.RESULTS 10,20,40 μmol/L Trametenolic acid B had good growth-inhibitory effects on HGC-27 cells,blocked in G0/G1 phase,in a dose-dependent and time-dependent manner,but had no obvious effect on cell apoptosis.After treatment with 20 μmol/L trametenolic acid B for 24 h,a large number of autophagy vacuoles and autophagy bodies were observed under transmission electron microscope,and the proportion of cell autophagy was significantly increased with higher dose of TAB;TAB promoted the transformation of type Ⅰ microtubule-associated protein 1 light chain 3 (LC3 Ⅰ) to type Ⅱ microtubule-associated protein 1 light chain 3 (LC3 Ⅱ),up-regulated the expressions of myosin-like B-cell lymphoma-2 (Bcl-2) interacting protein (Beclin-1) and cyclin-dependent kinase inhibitor 1A (p21),and inhibited the CCND1 gene protein (CyclinD1) expression.CONCLUSION Trametenolic acid B can induce the autophagic death of HGC-27 cells,but it has no significant effect on cell apoptosis.

Down-regulation of microRNA-181 b has protective effect on cerebral is-chemic injury of mice / 中国病理生理杂志

AIM:To explore the role of microRNA-181b (miR-181b) in ischemic injury and autophagy pro-tein 5 (Atg5) levels of mice .METHODS:Oxygen-glucose depletion (OGD) model in N2A cells to mimic ischemic in-jury in vitro was established .A middle cerebral artery occlusion ( MCAO) model to mimic ischemic injury in vivo was also induced in mice.The N2A cell apoptosis after OGD was assessed by in situ cell death detection kit.The Atg5 and caspase-9 expressions were determined by Western blotting .Luciferase reporter assay was performed to identify the direct binding of miR-181b with 3’-UTR of Atg5 mRNA.RESULTS:The alteration of miR-181b expression level by transfection with pre-miR-181b or anti-miR-181b significantly affected N2A cell apoptosis (P<0.05).Accordingly, the changes of miR-181b levels significantly altered the protein level of Atg 5 ( P<0.05 ) .Co-transfection of the luciferase reporters with pre-miR-181b or anti-miR-181b resulted in the inhibition or enhancement of the luciferase activities of luciferase expressing plasmid containing 3’-UTR of Atg5 mRNA (P<0.05).In addition, the miR-181b antagonist significantly reduced the cleaved caspase-9 levels in cerebral ischemic cortex of the mice after MCAO ( P<0.05 ) .CONCLUSION: Down-regulation of miR-181b plays an important role in ischemic injury of mice through regulating Atg 5 protein level.

Identification of Atg8 Isoform in Encysting Acanthamoeba

Autophagy-related protein 8 (Atg8) is an essential component of autophagy formation and encystment of cyst-forming parasites, and some protozoa, such as, Acanthamoeba, Entamoeba, and Dictyostelium, have been reported to possess a type of Atg8. In this study, an isoform of Atg8 was identified and characterized in Acanthamoeba castellanii (AcAtg8b). AcAtg8b protein was found to encode 132 amino acids and to be longer than AcAtg8 protein, which encoded 117 amino acids. Real-time PCR analysis showed high expression levels of AcAtg8b and AcAtg8 during encystation. Fluorescence microscopy demonstrated that AcAtg8b is involved in the formation of the autophagosomal membrane. Chemically synthesized siRNA against AcAtg8b reduced the encystation efficiency of Acanthamoeba, confirming that AcAtg8b, like AcAtg8, is an essential component of cyst formation in Acanthamoeba. Our findings suggest that Acanthamoeba has doubled the number of Atg8 gene copies to ensure the successful encystation for survival when 1 copy is lost. These 2 types of Atg8 identified in Acanthamoeba provide important information regarding autophagy formation, encystation mechanism, and survival of primitive, cyst-forming protozoan parasites.