Toxic effect and mechanism of bis-benzylidine piperidon and proteasome inhibitor on tongue cancer cells / 中国药理学通报

Aim To investigate the toxic effects dibenzylidene piperidine RA190 and proteasome inhibitor MG132 on tongue cancer cell line CAL27 and TCA8113 and its mechanisms. Methods Different concentrations of RA190 or MG132 were exposed to tongue cancer cells for 24 hours. CCK-8 assay was used to detect the survival of CAL27 and TCA8113 cells, and flow cytometry was used to analyze the cell cycle and apoptosis of different groups of tongue cancer cells. Western blot was used to detect the expression of ADRM1, Cyclin B1, Bak and Bax protein in each group. Results The semi-inhibitory (IC

Down-regulation effects of IFN-alpha on p11, 5-htr1b and 5-HTR4 protein levels were affected by NH4CL or MG132 treatment in SH-sy5y cells

Chondrosenescence (chondrocyte senescence) and subchondral bone deterioration in osteoarthritic rats were analyzed aftertreatment with the estrogenic herb Labisia pumila (LP) or diclofenac. Osteoarthritis (OA) was induced in bilaterallyovariectomized (OVX) rats by injecting mono-iodoacetate into the right knee joints. Rats were grouped (n = 8) into nontreated OVX?OA control, OVX?OA ? diclofenac (5 mg/kg) (positive control), OVX?OA ? LP leaf extract (150 and300 mg/kg) and healthy sham control. After 8 weeks’ treatment, their conditions were evaluated via serum biomarkers,knee joint histology, bone histomorphometry, protein and mRNA expressions. The LP significantly reduced cartilageerosion, femur bone surface alteration, bone loss and porosity and increased trabecular bone thickness better than diclofenacand the non-treated OA. The cartilage catabolic markers’ (matrix metalloproteinase (MMP)-13, RUNX2, COL10a, ERa,CASP3 and HIF-2a) mRNA expressions were down-regulated and serum bone formation marker, PINP, was increased byLP in a dose-dependent manner. The LP (containing myricetin and gallic acid) showed protection against chondrosenescence, chondrocyte death, hypoxia-induced cartilage catabolism and subchondral bone deterioration. The bone and cartilageprotective effects were by suppressing proteases (collagen break-down), bone resorption and upregulating subchondralbone restoration. The cartilage ERa over-expression showed a strong positive correlation with MMP-13, COL10a1, histological, micro-computed tomography evidence for cartilage degradation and chondrosenescence.

Effect of MG132 on acute myeloid leukemia cell proliferation and apoptosis / 中国药理学通报

Aim: To investigate the effect of proteasome inhibitor MG132 on the proliferation and apoptosis of acute myeloid leukemia cells. Methods: qRT-PCR was used to detect the expression of ADRM1 mRNA in nine blood tumor cell lines. The expression of ADRM1 in HL60 cells was interfered by shRNA; HL60 cells before and after ADRM1 interfered were treated with different MG132 concentrations for 24 h; Then, the cell proliferation and viability were measured with CCK-8 by microplate reader. Meanwhile, the expressions of ADRM1 and UCH37 protein were detected by Western blot. Apoptosis of HL60 and NB4 cells treated with different MG132 concentrations was analyzed by flow cytometry. Results: ADRM1 mRNA was up-regulated in blood tumor cell lines. ADRM1 shRNA and scrambled shRNA HL60 cells were successfully constructed. Cell proliferation and viability were inhibited by AD-RM1 shRNA interference or decreased with the increase of MG132 concentration; meanwhile, ADRM1 and UCH37 protein expressions were down-regulated. The apoptosis of HL60 and NB4 cells increased with the increase of MG132 concentrations. The apoptotic effect of MG132 on HL60 cells was stronger than that of NB4 cells. Conclusions: ADRM1 mRNA is overexpressed in blood tumor cell lines; ADRM1 down-regulation induces UCH37 protein decrease and cell proliferation inhibition. MG132 induces AML cell apoptosis and restrains the proliferation and viability through down-regulating the expression of ADRM1 and UCH37 protein. The apoptotic effect of MG132 on different types of AML cells exists individual differences.

Endoplasmic reticulum stress and proteasome pathway involvement in human podocyte injury with a truncated COL4A3 mutation / 中华医学杂志(英文版)

Background@#Collagen type IV (COL4)-related nephropathy includes a variety of kidney diseases that occur with or without extra-renal manifestations caused by COL4A3-5 mutations. Previous studies revealed several novel mutations, including three COL4A3 missense mutations (G619R, G801R, and C1616Y) and the COL4A3 chr:228172489delA c.4317delA p.Thr1440ProfsX87 frameshift mutation that resulted in a truncated NC1 domain (hereafter named COL4A3 c.4317delA); however, the mutation mechanisms that lead to podocyte injury remain unclear. This study aimed to further explore the mutation mechanisms that lead to podocyte injury.@*Methods@#Wild-type (WT) and four mutant COL4A3 segments were constructed into a lentiviral plasmid, then stably transfected into human podocytes. Real-time polymerase chain reaction and Western blotting were applied to detect endoplasmic reticulum stress (ERS)- and apoptosis-related mRNA and protein levels. Then, human podocytes were treated with MG132 (a proteasome inhibitor) and brefeldin A (a transport protein inhibitor). The human podocyte findings were verified by the establishment of a mus-Col4a3 knockout mouse monoclonal podocyte using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technology.@*Results@#Our data showed that COL4A3 mRNA was significantly overexpressed in the lentivirus stably transfected podocytes. Moreover, the COL4A3 protein level was significantly increased in all groups except the COL4A3 c.4317delA group. Compared to the other test groups, the COL4A3 c.4317delA group showed excessive ERS and apoptosis. Podocytes treated with MG132 showed remarkably increased intra-cellular expression of the COL4A3 c.4317delA mutation. MG132 intervention improved higher ERS and apoptosis levels in the COL4A3 c.4317delA group. Mouse monoclonal podocytes with COL4A3 chr:82717932insA c.4852insA p.Arg1618ThrfsX4 were successfully acquired; this NC1-truncated mutation suggested a higher level of ERS and relatively remarkable level of apoptosis compared to that of the WT group.@*Conclusions@#We demonstrated that excessive ERS and ERS-induced apoptosis were involved in the podocyte injury caused by the NC1-truncated COL4A3 mutation. Furthermore, proteasome pathway intervention might become a potential treatment for collagen type IV-related nephropathy caused by a severely truncated COL4A3 mutation.

Effects of a Proteasome Inhibitor on Cardiomyocytes in a Pressure-Overload Hypertrophy Rat Model: An Animal Study

BACKGROUND: The ubiquitin-proteasome system (UPS) is an important pathway of proteolysis in pathologic hypertrophic cardiomyocytes. We hypothesize that MG132, a proteasome inhibitor, might prevent hypertrophic cardiomyopathy (CMP) by blocking the UPS. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and androgen receptor (AR) have been reported to be mediators of CMP and heart failure. This study drew upon pathophysiologic studies and the analysis of NF-κB and AR to assess the cardioprotective effects of MG132 in a left ventricular hypertrophy (LVH) rat model. METHODS: We constructed a transverse aortic constriction (TAC)-induced LVH rat model with 3 groups: sham (TAC-sham, n=10), control (TAC-cont, n=10), and MG132 administration (TAC-MG132, n=10). MG-132 (0.1 mg/kg) was injected for 4 weeks in the TAC-MG132 group. Pathophysiologic evaluations were performed and the expression of AR and NF-κB was measured in the left ventricle. RESULTS: Fibrosis was prevalent in the pathologic examination of the TAC-cont model, and it was reduced in the TAC-MG132 group, although not significantly. Less expression of AR, but not NF-κB, was found in the TAC-MG132 group than in the TAC-cont group (p<0.05). CONCLUSION: MG-132 was found to suppress AR in the TAC-CMP model by blocking the UPS, which reduced fibrosis. However, NF-κB expression levels were not related to UPS function.

MG132 Affects on the Nude Mice Transplanted Tumor Tissues of Ovarian Epithelial Carcinoma and the Relationship with Cisplatin Combination / 实用妇产科杂志

Objective:To investigate the potential value and feasibility of MG132 as a new therapy method for the ovarian cancer and a cisplatin chemotherapy-synergistic agent.Methods:The mode of the nude mice transplanted tumor tissues of ovarian epithelial carcinoma were established,20 nude mice were randomly divided into four groups and were all intrapedtoneal injected,once a day,a total of seven days:①Control group(0.2 ml saline),②MG132 group(2 mg/kg),③Cisplatin group(1 mg/kg),④Combination group[MG132(2 mg/kg) + cisplatin (1 mg/kg)].The weight inhibitory rates of tumors in each group were compared after four weeks.The expressions of Caspase3,Beclin1 in each group were detected by IHC,FIA,western blot and RT-PCR.Results:①The inhibitory rate of tumors in cisplatin group,MG132 group,and combination group was 53.85％,15.38％,88.46％,respectively,the additive effect of cisplatin and MG132 combination therapy was 60.95％.②IHC,FIA,western blot detected that compared to control group,the positive expressions of Beclin1,Caspase3 were increased in cisplatin group,MG132 group,and combination group,among which combination group increased more.③RT-PCR detected that the mRNA relative quantity of Beclin1 in cisplatin group,MG132 group,combination group respectively were higher than that of control group(P＜0.05);and it was higher in combination group than that of cisplatin group and MG132 group(P＜0.05).Conclusions:The growth of nude mice transplanted tumor tissues of ovarian epithelial carcinoma can be inhibited by MG132,and has a synergistic effect for treating ovarian cancer by combination with cisplatin,it is expected to be an effective anti-tumor drug for platinum resistant refractory ovarian cancer.

Proteasome Inhibitor MG132 Inhibits Cell Proliferation and Induces Cell Apoptosis in Acute T Lymphoblastic Leukemia Cell Via FOXO3a/Puma Pathway / 中山大学学报(医学科学版)

[Objective]To explore the effect and the possible mechanism of the proteasome inhibitor MG132 on acute T lympho?blastic leukemia cells.[Methods]The influence of different concentrations of MG132 in the viability and proliferation of CCRF-CEM was measured by MTS. Apoptosis rates of CCRF-CEM treated by MG132 were determined by flow cytometry. After being exposed to MG132,the protein levels of FOXO3a in cytoplasm and nucleus were analyzed by Western blotting. qRT-PCR was applied to detect the mRNA of FOXO3a and Puma in cells treated by MG132. Then CCRF-CEM was stably transfected with antisense FOXO3a using Lentivirus infection. We further investigated the effects of MG132 in FOXO3a-shRNA cells and elucidated the mechanisms of FOXO3a and Puma.[Results]MG132 inhibits the proliferation of CCRF-CEM,but has no cytotoxicity in peripheral blood mononu?clear cells(PBMC). Cellular apoptosis was induced in cells treated with MG132. At mRNA level,MG132 had no influence on FOXO3a,but increased the expression of Puma. However,MG132 promoted the expression of both FOXO3a and Puma at protein level. Interestingly,the expression of FOXO3a increased very little in cytoplasm. In FOXO3a-shRNA cells the expression of FOXO3a and Puma decreased at protein level. FOXO3a's knockdown attenuated the proliferation inhibition mediated by MG132.[Conclusion]MG132 inhibits the proliferation and promotes to apoptosis of CCRF-CEM. One of the mechanism is that MG132 inhib? its the degradation of FOXO3a,and then activates FOXO3a/Puma pathway.

Degradation of eNOS induced by TNF-α in human umbilical vein endothelial cells / 基础医学与临床

Objective To investigate does intracellular protein degradation pathway play an important role in decrease of endothelial nitric oxide synthase (eNOS) in human umbilical vein endothelial cells (HUVECs).MethodsTo establish a primary HUVECs culture methods,the HUVECs were incubated with concentration gradient group of TNF-α(0.01,0.1,1 and 10 ng/mL) in different time periods (24,48 and 72 h).The HUVECs were pretreated with NH4Cl or treated with caspase inhibitor or MG-132 1.5 h prior to incubation for an additional 24 h with TNF-α.The expression of eNOS was detected via Western blot assay.Results Treatment of the HUVECs with TNF-α(0.01-10 ng/mL) led to a dose-dependent reduction of eNOS expression.And treatment with TNF-α(1 ng/mL) reduced the eNOS expression in a time-depended manner.Compared with the TNF-α group,the protein expression level of eNOS was obviously increased in the co-working group of MG-123 and TNF-α.Conclusions TNF-α induces degradation of eNOS through a ubiquitin-proteasome pathway.

Intervention effect of proteasome inhibitor MG132 in rats with collagen-induced arthritis / 中国免疫学杂志

Objective:To explore the intervention effect of proteasome inhibitor MG132 in rats with collagen-induced arthritis(CIA),which resembles human rheumatoid arthritis(RA).Methods:Forty-eight female SD rats were randomly divided into three groups,including blank control group,CIA model group and MG132-treated group.There were sixteen rats in each group.Rats in CIA model group and MG132-treated model group were injected with type Ⅱ collagen to established CIA rats.21 days after the initial immunization,the rats in the MG132-treated model group were injected subcutaneously with 1 mg/kg MG132 once daily for 2 weeks.42 days after the initial immunization,the change of paw-swelling and the arthritis scores were determined.The synovial pathology examination was performed with HE staining.The 20S proteasome activity in synovial tissue was measured by fluorescence substrate assay.The expression of NF-κB/p65,IκBα in synovial tissue were analyzed by Western blot.Results:Proteasome inhibitor MG132 significantly attenuated the severity of arthritis and histopathological changes in CIA rats.Compared with the blank control group,the 20S proteasome activity was increased significantly in the CIA model group(P<0.05),and decreased after injection of MG132.Compared with CIA rats,the expression of NF-κB/p65 significantly decreased in rats treated with MG132(P<0.01).Compared with the blank control group,the expression of IκBα protein decreased in CIA model group.After injected with MG132,the protein was significantly increased(P<0.01).Conclusion:The proteasome inhibitor MG132 may attenuates the severity of arthritis and histopathological changes in CIA rats.These effects may be mediated through the inhibition of NF-κB activity.

Effect of MG132 on Aβgeneration in SH-SY5Y cells / 中国病理生理杂志

[ ABSTRACT] AIM:To observe the influences of different concentrations of MG132 on apoptosis and beta-amyloid protein ( Aβ) generation in SH-SY5Y cells, and to explore the underlying mechanism.METHODS:SHSY-5Y cells were incubated with MG132 for 24 h.The final concentrations of MG132 were 2.5, 5 and 10μmol/L.The cell viability was de-termined by MTT assay.The cell apoptosis was assessed by flow cytometry.The levels of Aβwere measured by ELISA. The relative protein levels were detected by Western blot.RESULTS:In the SH-SY5Y cells, MG132 reduced the cell via-bility, induced the cell apoptosis, increased the level of Aβ, and increased the expression of the related proteins for Aβgeneration in a concentration-dependent manner.CONCLUSION: MG132 induces apoptosis and increases the levels of Aβ1-42 and Aβ1-40 by regulating the proteins related to Aβgeneration in the SH-SY5Y cells.

Effects of MG132 on protein expression of SnoN and fibrosis-related in-dicators in NRK-52E cells after incubated with high concentration of glu-cose / 中国病理生理杂志

AIM:To investigate the effects of proteasome inhibitor MG 132 on the expression of SnoN in renal tubule epithelial cells incubated in high glucose , and to explore the possible mechanism and function that MG 132 reduces or slows down renal tubular interstitial injury after incubated in high glucose .METHODS:The NRK-52E cells were divid-ed into normal control group (NG), high glucose group (HG) and high glucose plus pretreatment with different doses of MG132 group (HG+MG132).The immunofluorescence staining was used to detect the protein expression of E-cadherin and α-smooth muscle actin (α-SMA) in NRK-52E cells under different conditions .The relative protein expression levels of SnoN, Smad ubiquitination regulatory factor 2 (Smurf2), Arkadia, E-cadherin, α-SMA and collagen type Ⅰ(Col-Ⅰ) were detected by Western blotting .RESULTS:Compared with NG group , the expression of E-cadherin and SnoN was de-creased (P<0.05), while the expression of α-SMA, Col-Ⅰ, Smurf2 and Arkadia was increased (P<0.05).Compared with HG group, the protein expression of SnoN and E-cadherin was significantly up-regulated in HG+MG132 group ( P<0.05 ) , and the protein expression of α-SMA and Col-Ⅰwas significantly down-regulated in a dose-depended manner ( P<0.05).However, no effect on the protein expression of Smurf2 and Arkadia was observed.CONCLUSION: MG132 in-hibits the degradation of SnoN protein induced by high glucose , thus reducing the renal fibrosis .

Inhibitory effect of MG132 on proliferation, migration and epithelial-mesenchymal transition of human lens epithelial cells / 中华实验眼科杂志

Background The primary pathologic mechanism of posterior capsular opacification (PCO) is proliferation,migration and epithelial-mesenchymal transition (EMT) of residuary lens epithelial cells (LECs) after cataract extract surgery.Researches showed that MG132,a proteasome inhibitor,can attenuate the proliferation of bovine LECs,but its effect on human LECs remains unclear.Objective This study was to investigate the inhibitory effect of MG132 on proliferation,migration and differentiation of human LECs in vitro.Methods Human lens capsule were collected during the surgery.Human LECs were primarily cultured by explant method and passaged.The second or third generation of cells were incubated to 96-well plates at the density of 5×105/ml (200 μl/well) for 24 hours.Fibroblast growth factor-2 (FGF-2,10 mg/L),MG132 (10 μmol/L) or MG132+FGF-2 was added into the culture medium for 24 hours separately,and regular cultured cells served as the control group.The proliferation value (absorbance,A490) of the cells was assayed by MTT colorimetric method.A bare area was made by a sterile cotton swab in the cell layer,and migrated cell number in the blank zone was counted to evaluate the migration ability of the cells after 24 hours.Transforming growth factor-32(TGF-β2),MG132 or MG132+TGF-β2 was added into the culture medium for 24 hours separately,and the expression of fibronectin (FN) in the cells was detected using immunochemistry.Results The proliferation values (A490) of the cells were 0.582±0.020,0.723±0.010,0.434± 0.011 and 0.465±0.008 in the control group,FGF-2 group,MG132 group and MG132 + FGF-2 group,respectively,showing a significant difference among the groups (F =110.482,P＜0.01).The A value was significantly higher in the FGF-2 group and lower in the MG132 group and MG132+FGF-2 group than that of the control group (all at P＜ 0.05).The migrated cell number was 8.67 ± 1.08,11.58 ± 1.59,2.67 ± 0.09 and 2.75 ± 0.09 in the control group,FGF-2 group,MG132 group and MG132+FGF-2 group,respectively,with a significant difference among the groups (F=34.301,P＜0.01),and more cells in the blank zone were seen in the FGF-2 group and less cells were in the MG132 group and MG132+FGF-2 group in comparison with the control group (all at P＜0.05).Compared with the control group,the proliferative rate and migrating rate of the cells declined by 25.4％ and 75.0％ in the MG132 group as well as 20.1％ and 68.3％ in the MG132+FGF-2 group,but in the FGF-2 group,they increased by 24.2％ and 33.6％.The expressing levels (A value) of FN in the LECs were 1.242±0.023,2.329±0.113,1.043 ±0.021 and 1.163±0.018 in the control group,TGF-β2 group,MG132 group and MG132 +TGF-β2 group,respectively,with a significant difference among the groups (F =113.752,P＜0.01),a considerably increased expressing value was seen in the TGF-β2 group and decreased value was in the MG132 group and MG132+TGF-β2 group when compared with the control group (all at P＜0.05).Conclusions MG132 can effectively inhibit the proliferation,migration and differentiation of human LECs in vitro.

Transcriptional Upregulation of Plasminogen Activator Inhibitor-1 in Rat Primary Astrocytes by a Proteasomal Inhibitor MG132

Plasminogen activator inhibitor-1 (PAI-1) is a member of serine protease inhibitor family, which regulates the activity of tissue plasminogen activator (tPA). In CNS, tPA/PAI-1 activity is involved in the regulation of a variety of cellular processes such as neuronal development, synaptic plasticity and cell survival. To gain a more insights into the regulatory mechanism modulating tPA/PAI-1 activity in brain, we investigated the effects of proteasome inhibitors on tPA/PAI-1 expression and activity in rat primary astrocytes, the major cell type expressing both tPA and PAI-1. We found that submicromolar concentration of MG132, a cell permeable peptide-aldehyde inhibitor of ubiquitin proteasome pathway selectively upregulates PAI-1 expression. Upregulation of PAI-1 mRNA as well as increased PAI-1 promoter reporter activity suggested that MG132 transcriptionally increased PAI-1 expression. The induction of PAI-1 downregulated tPA activity in rat primary astrocytes. Another proteasome inhibitor lactacystin similarly increased the expression of PAI-1 in rat primary astrocytes. MG132 activated MAPK pathways as well as PI3K/Akt pathways. Inhibitors of these signaling pathways reduced MG132-mediated upregulation of PAI-1 in varying degrees and most prominent effects were observed with SB203580, a p38 MAPK pathway inhibitor. The regulation of tPA/PAI-1 activity by proteasome inhibitor in rat primary astrocytes may underlie the observed CNS effects of MG132 such as neuroprotection.

Effects of proteasome inhibitor MG132 on memory acquisition and retrieval in one-trial passive avoidance in mice / 中华行为医学与脑科学杂志

Objective To investigate the effects of proteasome inhibitor MG132 on memory acquisition and memory retrieval in one-trail passive avoidance for mice.Methods MG132 (25 mg/kg) was administrated at different time points to analyze the time-dependent effects of MG132 on hippocampus proteasome activity.MG132 (25 mg/kg) was administrated 3 hours before-training or 1.5 hours pre-test to investigate the effect on memory acquisition and retrieval.The interaction of low dose (12 mg/kg) of MG132 and novelty interference on memory retrieval to studied.Results Hippocampus proteasome activity was significantly blocked when MG132 (25 mg/kg) was administrated 0.5-1.5 hours before analysis.The inhibition recovered as time passing and backed to normal state 24 hours later.A significant difference was showed between vehicle and pre-training,pre-test group (pre-training vehicle (296.03 ± 3.97) s,pre-training (173.30 ± 47.51) s ; pre-test vehicle (199.23 ± 43.01) s,pre-test (44.10 ± 11.16) s).Proteasome inhibitor did not produce a significant effect on memory retrieval (vehicle (174.19 ± 30.54)s,lower dose (174.19± 30.54)s),then only together with a novelty task the retrieval was significantly altered(vehicle (164.02 ±35.26)s,MG132 +novelty group (84.70 ±23.92)s).Conclusion Proteasome inhibitor MG132 can inhibit memory acquisition and memory retrieval.Thereby the effect on memory retrieval is enhanced by novelty.Thus,a physiological proteasome activity is essential for learning abilities.

Effect of MG132 on the expression of ERK1/2 and connective tissue growth factor in rat peritoneal mesothelial cells induced by high glucose / 中华肾脏病杂志

Objective To observe the effect of MG132 on the expression of extracellular regulated kinase 1/2 (ERK1/2) and connective tissue growth factor (CTGF) in rat peritoneal mesothelial cells (RPMCs) induced by high glucose.Methods RPMCs were isolated,cultured and passaged by trypsin,then identified.The second generation of cultured RPMCs were used in the experiment.RPMCs were divided into normal control group,high glucose (1.5％,2.5％,4.25％) for 24 hours,high glucose (2.5％) for 0,12,24,48 hours,incubated with MG132 (0.5,1,2 μmol/L) for half an hour and then with high glucose (2.5％) for 24 hours.ERK1/2 protein was detected by Western blotting,and CTGF protein in supernatant was detected by ELISA.Results Compared with the control group,the expression of p-ERK1/2 was significantly increased in the groups stimulated by high glucose (P ＜0.01),reached the peak at 24th hour (P ＜ 0.01),and then the expression decreased at 48th hour,but still was higher than that in the normal control group (P ＜ 0.01).CTGF protein expression of RPMCs induced by high glucose increased,in time-and dose-dependent manner (P ＜ 0.05).MG132 could significantly decrease the expression of ERK1/2 and CTGF induced by high glucose (P＜0.05).Conclusions MG132 can decrease the expression of p-ERK1/2 and CTGF in RPMCs induced by high glucose.The ubiquitin proteasome pathway participates in the development of peritoneal fibrosis,and blocking the way may contribute to the prevention of peritoneal fibrosis.

MG132 enhances the renal anti-oxidative ability in diabetic nephropathy rats / 中华肾脏病杂志

Objective To investigate the effects of MG132 on diabetic nephropathy (DN) rats induced with streptozocin. Methods Seventy-two male SD rats were randomly divided into three groups: normal control group (NC, n=24), DN group (n=24) and DN treated with MG132 group (DN+MG132, n=24). At the end of 4, 8 and 12 weeks, 24 hour urinary protein excretion rate (UPER) was detected. Morphology of kidney was examined by special staining of periodic acid-schiff (PAS). Renal 26S proteasome activity was determined by quantifying the hydrolysis of S-LLVY-AMC in a fluorescence reader. Urinary malondialdehyde (MDA) level and renal SOD and GSH-PX activity were detected by commercial kits. Renal SOD, GSH-PX and p47phox mRNA expressions were determined by real-time fluorescence PCR. Renal p47phox protein expression wasdetermined by Western blotting. Results Compared with NC group, the DN group showed a significant increased of UPER at week 4, 8, 12 (all P<0.05), of mesangium proliferation and mesangial matrix expansion at week 12. In DN+MG132 group, UPER was significantly decreased compared with DN group at the end of 4, 8 and 12 weeks (P<0.05, respectively), and the glomeruler pathological alteration induced by diabetes was attenuated. Increased renal 26S proteasome activity in DN rats was significantly inhibited after MC132 administration (P<0.05). Moreover, renal p47phox mRNA expression in DN group was 155%, 149% and 120% more than those in NC group at 3 time points (all P<0.05), and so was the renal p47phox protein expression, 139%, 152% and 186% more (all P<0.05). Urinary MDA levels in DN group were 1.95-, 2.04-and 2.62-folds more than those in NC group (all P<0.05). In addition, compared with NC group at 3 time points, in DN group, renal SOD activity was decreased by 23.09%, 33.59% and 53.31% (all P<0.05); renal GSH-PX activity was decreased by 28.57%, 33.06% and 48.76% (all P< 0.05); renal SOD mRNA was decreased by 38.09%, 61.44% and 76.53% (all P<0.05); renal GSH-PX mRNA group was decreased by 29.16%, 37.26% and 62.40% (all P<0.05). Compared with DN group, renal p47phox mRNA and protein expression, and urinary MDA levels were significantly lower in DN+MG132 group (all P<0.05); renal SOD and GSH-PX activity as well as mRNA expression were significantly increased in DN+MG132 group (all P<0.05). Conclusions MG132 treatment can provide renoprotection for DN rats effectively maybe through enhancing renal anti-oxidative ability.

Up-regulation of the DR5 Expression by Proteasome Inhibitor MG132 Augments TRAIL-Induced Apoptosis in Soft Tissue Sarcoma Cell Lines / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Current chemotherapeutics for treating locally advanced or metastatic soft tissue sarcomas (STS) are limited. Accordingly, the present in vitro study was conducted to evaluate the effects of treatment of STS cells with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) applied as a single agent or in combination with a proteasome inhibitor, MG132. MATERIALS AND METHODS: Sensitivity to TRAIL and activity of TRAIL-induced apoptotic pathways were analyzed in four STS cell lines: HTB-82 (rhabdomyosarcoma), HT-1080 (fibrosarcoma), HTB-93 (synovial sarcoma), and HTB-94 (chondrosarcoma). Reduction of the dye dimethylthiazolyl 2,5 diphenyltetrazolium bromide (MTT) was used to evaluate cytotoxic activity; western blots were used to evaluate TRAIL-induced apoptosis. RESULTS: TRAIL induced apoptosis in HTB-93 cells, but had little effect in HTB-82, HT-1080, or HTB-94 cells. Expression of TRAIL receptor-1 and -2 did not correlate with sensitivity to TRAIL. Co-incubation of cells with TRAIL and a proteasome inhibitor, MG132, augmented the apoptotic effect of TRAIL in both TRAIL-sensitive and TRAIL-resistant cells. This effect was due to up-regulation of TRAIL receptors and members of the pro-apoptotic BCL-2 family by MG132. CONCLUSION: These data show that combining TRAIL with MG132 enhances apoptosis and overcomes TRAIL resistance. This restoration of TRAIL sensitivity occurs through an increase in the expression of death receptor 5 and of pro-apoptotic BCL-2 family members such as BAX.

Effect of high glucose environment on the NF-κB/Iκ B signal pathway in cultured rat glomerular mesangial cell and its mechanism / 中华内分泌代谢杂志

To explore the effect of high glucose on the NF-κB/IκB signal pathway in cultured rat glomerular mesangial cells. The results showed that high glucose increased the degradation of IκB-α and the translocation to nucleus of NF-κB. These changes could be reverted mostly by MG132, a proteasome inhibitor. It suggests that the activation of the NF-κB signal pathway by high glucose concentration may probably be via the ubiquitin-proteasome pathway.

Role of endoplasmic reticulum stress in human brain gliomas cell apoptosis induced by proteasome inhibitor MG-132 / 肿瘤研究与临床

Objective To investigate the role of endoplasmic reticulum stress ( ERS) in human brain gliomas cell(SHG-44) apoptosis induced by proteasome inhibitor MG-132. Methods Human glioma cells were passage cultured. Glioma cells were treated by MG-132 with varying concentration(5, 10, 15 and 50 μmol/L) for 24 h. Compared with cells prior to the treatment (control group), cell viability was detected by MTT assay and the expression of ERS associated proteins GRP78 and apoptosis associated proteins Caspsse-12 was examined by PCR and Western-blotting. Results After MG-132 treatment for 24 h, SHG-44 cell viability was decreased significantly (39 %) (P <0.05), and continued to show a significant decline with the increasing concentration of MG-132 (P <0.05). RT-PCR results showed that the expression of ERS associated proteins GRP78 in SHG-44 cells were significantly increased after 5, 10, 15 and 50 μmol/L MG-132 treatment, and the expression of Caspase-12 was significantly increased after 5 μmol/L MG-132 treatment, slightly increased after 10 and 15 μmol/L treatment compared with that after 5 μmol/L treatment and reached the peak after 50 μmol/L treatment. Western-blotting results of GRP78 in SHG-44 cells were same as results of RT-PCR. Conclusion ERS may be involved in the apoptosis of gliomas cells induced by proteasome inhibitor MG-132.

Effect of proteasome inhibitor MG132 on proliferation and cell cycle distribution of NK/T cell lymphoma cells / 中国病理生理杂志

AIM: To study the influence of MG132 on the proliferation and cell cycle distribution of NK/T cell lymphoma cells, and to investigate the potential role of proteasome inhibitor on the treatment of NK/T cell lymphoma. METHODS: NK/T cell lymphoma cells HANK1 were treated with proteasome inhibitor MG132, and the proliferation was evaluated by MTT assay. The morphological changes were observed under inverse microscope. The cell cycle distribution and apoptosis were detected using flow cytometry. RESULTS: The growth inhibitory rate of HANK1 cells was(57.72±7.44)% after cultured for 24 h with 1 μmol/L MG132 and was just(3.98±0.07)% after cultured for 24 h with 0.1 μmol/L MG132. The positive relationship between the concentration of MG132 and growth inhibitory rate was observed. On the other hand, after cultured for 24 h with 1μmol/L MG132, the cells in G_1 and G_2 phases were(72.33±3.44)% and(12.86±1.29)%, respectively, much higher than those in control group(63.63%±2.29% and 7.94%±1.91%, respectively). The early and late apoptosis rates in MG132 group were 33.57%±2.10% and 16.66%±0.47%, respectively, much higher than that in control group (7.18%±0.82% and 3.81%±1.06%, respectively). CONCLUSION: MG132 inhibits cell proliferation and induces cell cycle arrested at G_1 and G_2 phases, and cell apoptosis in NK/T cell lymphoma cells in a concentration dependent manner. Proteasome inhibitor may be a good drug to treat patients with advanced NK/T cell lymphomas.