Role Of Endoplasmic Reticulum Stress In SHG-44 Cell Apoptosis Induced By Proteasome Inhibitor MG-132

PartⅠRole of endoplasm ic reticulum stress in cell apoptosis induced by Proteasome inhibitor MG-132Objective To investigate the role of endoplasmic reticulum stress (ERS) in cell apop tosis induced by Proteasome inhibitor MG-132.Methods Culture hunman glioma by way of passage,select glioma cells were treated with MG-132.Before the treatment(control group) and 5,10,15 and 50μmol/l after the treatment the cellular viability was assessed by MTT assay, PCR and Western-bloting was employed to detect ERS associated proteins(GRP78) and apoptosis associated proteins(Caspsse-12).Result It was revealed by MTT assay that 24h after that, the cell viability of SHG-44 was decreased by 43%(P<0.05),and continued to be significantly decreased with concentration(P<0.05). It was indicated by RT-PCR that ERS associated proteins GRP78 of SHG-44 cells were significantly increased 5,10,15,50μmol/L after treatment,and Caspase-12 was slightly increased 5μmol/L after treatment and reached the peak 50μmol/L after treatment,and increased insignificantly 10,15μmol/L after treatment. It was indicated by western-blot that ERS associated proteins GRP78 of SHG-44 cells were slightly increased 5μmol/L after treatment and reached the peak 50μmol/L after treatment,and increased insignificantly 10,15μmol/L after treatment.Conclusion ERS may be involved in the apop tosis induced by proteasome inhibitor MG-132.PartⅡProteasome inhibitor MG-132 through JNK signal transduction pathway induced the endoplasmic reticulum stress-related mechanism analysis in SHG-44 cellObjective To investigate the role of endoplasmic reticulum stress (ERS) in cell apop tosis induced by Proteasome inhibitor MG-132. At the same time choose JNK signal pathway, using the specific JNK inhibitor SP600125 observed changes in the role of MG-132, Further analysis of MG-132 inducing glioma cells apoptosis in the role of the endoplasmic reticulum stress.Methods Culture hunman glioma by way of passage, The experimental group were given a final concentration of 5,10,15,50μmol/L of MG-132. Using MTT after half inhibitory concentration, Select the median effective concentration of the experiment. Experimental group was divided into five groups:normal control group, DTT group, MG-132 group, SP600125 groups, MG-132+SP600125 Group. After the end of the experiment, flow cytometry to detection of apoptosis situation, RT-PCR and Western-bloting to detect the endoplasmic reticulum stress indicators GRP78,, JNK expression.Results:MTT colorimetric assay was found,5μmol/L to achieve the best inhibitory concentrations,SHG-44 cell viability decreased 43%(P<0.05), After the experimental group, compared with the control group, MG-132 after 24h role, the apoptotic rate significantly increased (67.05±2.13% vs 6.05±3.42%, p<0.05), GRP78mRNA expression increased significantly (p<0.05); But for DTT, the apoptosis rate and expression of GRP78mRNA has increased (P<0.05). Compared with the DTT group, SP600125+MG-132 group has been lowered, but not as a separate group of SP600125 reduced significantly (p<0.05). Western-blot results showed that compared with the control group, MG-132 can cause ERS. The role of endoplasmic reticulum stress indicators of GRP78, JNK expression was significantly increased in the MG-132 group after 24h (p<0.05).In the DTT group, GRP78, JNKexpression was significantly increased (p<0.05),In the SP600125+MG-132 group,GRP78, JNKexpression has been reduced, but not as good as giving SP600125 group (p <0.05).Conclusions:1. MG-132 can induced apoptosis of glioma cells.2. MG-132 can induced apoptosis of glioma cells in the process, ERS is to play the major role of pathways.3. JNK inhibitor SP600125 can partially block the channels of endoplasmic reticulum stress, namely, JNK signaling pathway is one of the ways to play a role in apoptosis.