Objective: To study the influence of glycyrrhetinic acid(GA) on bronchial asthma(BA)smooth muscle proliferation and apoptosis as well as inflammatory factor expression and its molecular mechanism.Methods: Male SD guin...Objective: To study the influence of glycyrrhetinic acid(GA) on bronchial asthma(BA)smooth muscle proliferation and apoptosis as well as inflammatory factor expression and its molecular mechanism.Methods: Male SD guinea pigs were selected and made into asthma models, bronchial asthma smooth muscle cells were cultured and divided into BA group, GA group and GA + LM group that were treated with serum-free RPMI1640 culture medium, serumfree RPMI1640 culture medium containing 50 ng/mL glycyrrhetinic acid, serum-free RPMI1640 culture medium containing 50 ng/mL glycyrrhetinic acid and 100 ng/mL LM22B-10 respectively; normal guinea pigs were collected and bronchial smooth muscle cells were cultured as control group. The cell proliferation activity as well as the expression of proliferation and apoptosis genes, inflammatory factors and p-ERK1/2 was determined.Results: Proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6,YKL-40, protein expression of p-ERK1/2 of airway smooth muscle cell in BA group were significantly higher than those of control group while m RNA expression levels of Bax,caspase-9 as well as caspase-3 were significantly lower than that of control group(P < 0.05); proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40, protein expression of p-ERK1/2 of airway smooth muscle cell in GA group were significantly lower than those of BA group(P < 0.05) while the m RNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly higher than those of BA group(P < 0.05); proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40 of airway smooth muscle cell in GA + LM group were significantly higher than those of GA group(P < 0.05) while m RNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly lower that of GA group(P < 0.05).Conclusion: GA can inhibit the proliferation of bronchial smooth muscle cells and reduce the expression of inflammatory factors by inhibiting the phosphorylation of ERK1/2.展开更多
Objective:To explore the protective effect and its molecular mechanism of apoptosis signalregulating kinase 1(ASK1) inhibitor(GS-459679) on acetaminophen-induced liver injury in mice.Methods:The model of liver injury ...Objective:To explore the protective effect and its molecular mechanism of apoptosis signalregulating kinase 1(ASK1) inhibitor(GS-459679) on acetaminophen-induced liver injury in mice.Methods:The model of liver injury was established by administration of acetaminophen(APAP)(300 mg/kg,i.p.) on C57BL/6 mice.Forty-eight male C57BL/6 mice were randomly divided into four groups,consisting of control group,GS group(GS-459679,30 mg/kg,i.p.),APAPinduced group,and GS combined with APAP-induced group.For GS combined with APAPinduced group,mice were treated with GS 30 min prior to administration of APAP.After mice were euthanized at 6 h or 12 h.respectively,serum levels of alanine aminotransferase(ALT) and aspartate aminotransferase(AST) were analyzed,and mRNA levels of TNF- α,IL-6 and IL-1βwere tested.The activity of glutathione(GSH),oxidized GSH(GSSG) and malondialdehyde were quantified.In addition,ASK1,P-ASK1,JNK and P-JNK protein levels were tested in all groups.Results:The ASK1 and P-ASK1 levels were up-regulated in APAP-induced group.Compared to the control group,serum levels of ALT and AST.and mRNA levels of TNF- a,IL-6 and IL-1(3were increased in APAP-induced group.Meanwhile,the levels of MAD and GSSG.and the ratio of GSSG/GSH were higher and the JNK was activatedin APAP-induced group compared with that in control group.However,compared to APAP-induced group,GS combined with APAP-induced group displayed a decrease of protein expression levels of ASK 1,P-ASKI and P-JNK,a reduction of serum levels of ALT and AST,a decrease in TNF- a.IL-6 and IL-1(3 mRNA levels,and a low ration of GSSG/GSH.Conclusions:GS-459679 treatment effectively down-regulates ASK1 and P-ASK 1 expression.Addition of GS-459679 decreases the generation of liver metabolites and inflammatory factors,reduces oxidative stress reaction,inhibits JNK activation,and then protects the responsiveness to APAP-induced liver injury.展开更多
Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-reg...Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-regulated kinase(ERK)pathway is thought to increase cell proliferation and to protect cells from apoptosis.The aim of the study was to investigate the correlation between the ERK1/2 signaling pathway and XAF1 in colon cancer.Methods:Four human colon cancer cell lines,HCT1116 and Lovo(wildtype p53),DLD1 and SW1116(mutant p53),were used.Lovo stable transfectants with XAF1 sense and antisense were established.The effects of dominant-negative MEK1(DN-MEK1)and MEK-specific inhibitor U0126 on the ERK signaling pathway and expression of XAF1 and XIAP proteins were determined.The transcription activity of core XAF1 promoter was assessed by dual luciferase reporter assay.Cell proliferation was measured by MTT assay.Apoptosis was determined by Hoechst 33258 staining.Results:U0126 increased the expression of XAF1 in a time-and dose-dependent manner.A similar result was obtained in cells transfected with DN-MEK1 treatment.Conversely,the expression of XIAP was down-regulated.Activity of the putative promoter of the XAF1 gene was significantly increased by U0126 treatment and DN-MEK1 transient transfection.rhEGF-stimulated phosphorylation of ERK appeared to have little or no effect on XAF1 expression.Overexpression of XAF1 was more sensitive to U0126-induced apoptosis,whereas down-regulation of XAF1 by antisense reversed U0126-induced inhibition of cell proliferation.Conclusions:XAF1 expression was up-regulated by inhibition of the ERK1/2 pathway through transcriptional regulation,which required de novo protein synthesis.The results suggest that XAF1 mediates apoptosis induced by the ERK1/2 pathway in colon cancer.展开更多
We reported in this manuscript that TGF-beta1 induces apoptosis in AML12 murine hepatocytes, which is associated with the activation of p38 MAPK signaling pathway. SB202190, a specific inhibitor of p38 MAPK, strongly ...We reported in this manuscript that TGF-beta1 induces apoptosis in AML12 murine hepatocytes, which is associated with the activation of p38 MAPK signaling pathway. SB202190, a specific inhibitor of p38 MAPK, strongly inhibited the TGF-beta1-induced apoptosis and PAI-1 promoter activity. Treatment of cells with TGF-beta1 activates p38. Furthermore, over-expression of dominant negative mutant p38 also reduced the TGF-beta1-induced apoptosis. The data indicate that the activation of p38 is involved in TGF-beta1-mediated gene expression and apoptosis.展开更多
AIM:To analyze the effect of chemotherapeutic drugs and specific kinase inhibitors,in combination with the death receptor ligand tumor necrosis factor-related apoptosis inducing ligand(TRAIL),on overcoming TRAIL resis...AIM:To analyze the effect of chemotherapeutic drugs and specific kinase inhibitors,in combination with the death receptor ligand tumor necrosis factor-related apoptosis inducing ligand(TRAIL),on overcoming TRAIL resistance in hepatocellular carcinoma(HCC)and to study the efficacy of agonistic TRAIL antibodies,as well as the commitment of antiapoptotic BCL-2 proteins, in TRAIL-induced apoptosis. METHODS:Surface expression of TRAIL receptors (TRAIL-R1-4)and expression levels of the antiapoptotic BCL-2 proteins MCL-1 and BCL-xL were analyzed by flow cytometry and Western blotting,respectively. Knock-down of MCL-1 and BCL-xL was performed by transfecting specific small interfering RNAs.HCC cellswere treated with kinase inhibitors and chemotherapeutic drugs.Apoptosis induction and cell viability were analyzed via flow cytometry and 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. RESULTS:TRAIL-R1 and-R2 were profoundly expressed on the HCC cell lines Huh7 and Hep-G2. However,treatment of Huh7 and Hep-G2 with TRAIL and agonistic antibodies only induced minor apoptosis rates.Apoptosis resistance towards TRAIL could be considerably reduced by adding the chemotherapeutic drugs 5-fluorouracil and doxorubicin as well as the kinase inhibitors LY294002[inhibition of phosphoinositol- 3-kinase(PI3K)],AG1478(epidermal growth factor receptor kinase),PD98059(MEK1),rapamycin(mam- malian target of rapamycin)and the multi-kinase inhibitor Sorafenib.Furthermore,the antiapoptotic BCL-2 proteins MCL-1 and BCL-xL play a major role in TRAIL resistance:knock-down by RNA interference increased TRAIL-induced apoptosis of HCC cells.Additionally, knock-down of MCL-1 and BCL-xL led to a significant sensitization of HCC cells towards inhibition of both c-Jun N-terminal kinase and PI3K.CONCLUSION:Our data identify the blockage of survival kinases,combination with chemotherapeutic drugs and targeting of antiapoptotic BCL-2 proteins as promising ways to overcome TRAIL resistance in HCC.展开更多
A major problem which is poorly understood in the management of bladder cancer is low sensitivity to chemotherapy and high recurrence after transurethral resection. Insulin-like growth factor 1 receptor (IGF-1R) signa...A major problem which is poorly understood in the management of bladder cancer is low sensitivity to chemotherapy and high recurrence after transurethral resection. Insulin-like growth factor 1 receptor (IGF-1R) signaling plays a very important role in progression, invasion and metastasis of bladder cancer cells. In this study, we investigated whether IGF-1R was involved in the growth stimulating activity and drug resistance of bladder cancer cells. The results showed: The mRNAs of IGF-1, IGF-2 and IGF-1R were strongly expressed in serum-free cultured T24 cell line, whereas normal urothelial cells did not express these factors/receptors or only in trace levels; T24 cell responded far better to growth stimulation by IGF-1 than did normal urothelial cells; blockage of IGF1R by antisense oligodeoxynucleotide (ODN) significantly inhibited the growth of T24 cell and enhanced sensitivity and apoptosis of T24 cells to mitomycin (MMC). These results suggested that blockage of IGF-IR signaling might potentially contribute to the treatment of bladder cancer cells which are insensitive to chemotherapy.展开更多
目的观察盘龙七片对骨关节炎(osteoarthritis,OA)小鼠沉默信息转录调控因子(silent information regulator type 1,SIRT1)/核因子-κB(nuclear factor-kappa B,NF-κB)通路及软骨细胞凋亡的影响。方法手术切除右膝关节内侧半月板和前交...目的观察盘龙七片对骨关节炎(osteoarthritis,OA)小鼠沉默信息转录调控因子(silent information regulator type 1,SIRT1)/核因子-κB(nuclear factor-kappa B,NF-κB)通路及软骨细胞凋亡的影响。方法手术切除右膝关节内侧半月板和前交叉韧带复制小鼠OA模型。将小鼠分为正常对照组,模型组,阳性对照组,盘龙七片低、中、高剂量组。通过番红O-快速绿染色观察膝关节结构变化,进行Mankin评分评估关节炎严重程度,流式细胞术检测软骨细胞凋亡指数,qRT-PCR检测Bax、Bcl-2、Caspase-3 mRNA表达水平,Western blot法检测软骨细胞SIRT1、NF-κB蛋白表达水平。结果与正常对照组比较,模型组小鼠膝关节软骨细胞凋亡率增加,Bax、Caspase-3 mRNA和NF-κB蛋白表达水平显著增加,Bcl-2 mRNA和SIRT1蛋白表达水平显著降低,差异均有统计学意义(P<0.05);与模型组比较,阳性对照组与盘龙七片低、中、高剂量组小鼠膝关节软骨细胞凋亡率显著降低,Bax、Caspase-3 mRNA和NF-κB蛋白表达水平显著降低,Bcl-2 mRNA和SIRT1蛋白表达水平显著增加,差异均有统计学意义(P<0.05),盘龙七片的作用呈明显的剂量依赖性。结论盘龙七片可抑制OA小鼠膝关节软骨细胞凋亡,其作用机制可能与调节SIRT1/NF-κB信号通路相关。展开更多
目的:通过对硫氧还蛋白(Trx)突变体与凋亡信号调节激酶-1(ASK1)结合能力的研究,揭示Trx的氨基酸位点与其抗氧化抗凋亡性的关系,进一步阐述Trx在细胞凋亡中的作用。方法:构建人类野生型Trx(pcDNA-hTrx-H is tag,TrxA)和人类Trx 49位突变...目的:通过对硫氧还蛋白(Trx)突变体与凋亡信号调节激酶-1(ASK1)结合能力的研究,揭示Trx的氨基酸位点与其抗氧化抗凋亡性的关系,进一步阐述Trx在细胞凋亡中的作用。方法:构建人类野生型Trx(pcDNA-hTrx-H is tag,TrxA)和人类Trx 49位突变体(pcDNA-hTrx-Y49F-H is tag,TrxB)及ASK1质粒(pCDNA-ASK1-HA tag)。用TrxA、TrxB质粒分别与ASK1质粒共转染入HEK-293A细胞。实验分为对照组(CON)、ASK1质粒转染组、TrxA+ASK1质粒共转染组及TrxB+ASK1质粒共转染组。于转染24 h后,裂解细胞,裂解细胞前20 m in加入不同浓度的过氧化氢。将裂解产物进行W estern b lot检测转染的结果,运用免疫共沉淀(co-immunoprec ip itation)法检测ASK1与Trx在过氧化物作用下解离的程度,采用TUNEL法及检测Caspase-3的活性法检测HEK-293A细胞的凋亡。结果:与ASK1转染组细胞的凋亡指数(73.8±6.93)%及Caspase-3活性[(69.3±3.57)nmol/(h.mg蛋白)]相比,TrxA+ASK1共转染组细胞的凋亡率(49.8±4.62)%明显减少,Caspase-3的活性降低[(51.4±3.61)nmol/(h.mg蛋白)],(P<0.05)。TrxB+ASK1共转染组的凋亡率(22.4±5.07)%更少,Caspase-3的活性降低更明显[(30.1±2.48)nmol/(h.mg蛋白)](P<0.01)。与TrxA+ASK1共转染组相比,TrxB+ASK1共转染组的细胞凋亡数及Caspase-3的活性下降更明显(P<0.05)。此外,在过氧化氢干预下,TrxB与ASK1的结合同TrxA与ASK1的结合相比较,前者更紧密。结论:Trx中第49位的酪氨酸突变为苯丙氨酸后,Trx与ASK1的结合能力增强,Trx抗凋亡的作用明显增加。说明Trx与ASK1的结合能力与Trx的氨基酸位点明显相关,进而可影响Trx抗细胞凋亡的能力。展开更多
基金supported by Guangdong Medical Science and Technology Research Fund Project(No:A2017331)
文摘Objective: To study the influence of glycyrrhetinic acid(GA) on bronchial asthma(BA)smooth muscle proliferation and apoptosis as well as inflammatory factor expression and its molecular mechanism.Methods: Male SD guinea pigs were selected and made into asthma models, bronchial asthma smooth muscle cells were cultured and divided into BA group, GA group and GA + LM group that were treated with serum-free RPMI1640 culture medium, serumfree RPMI1640 culture medium containing 50 ng/mL glycyrrhetinic acid, serum-free RPMI1640 culture medium containing 50 ng/mL glycyrrhetinic acid and 100 ng/mL LM22B-10 respectively; normal guinea pigs were collected and bronchial smooth muscle cells were cultured as control group. The cell proliferation activity as well as the expression of proliferation and apoptosis genes, inflammatory factors and p-ERK1/2 was determined.Results: Proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6,YKL-40, protein expression of p-ERK1/2 of airway smooth muscle cell in BA group were significantly higher than those of control group while m RNA expression levels of Bax,caspase-9 as well as caspase-3 were significantly lower than that of control group(P < 0.05); proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40, protein expression of p-ERK1/2 of airway smooth muscle cell in GA group were significantly lower than those of BA group(P < 0.05) while the m RNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly higher than those of BA group(P < 0.05); proliferation activity value and m RNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40 of airway smooth muscle cell in GA + LM group were significantly higher than those of GA group(P < 0.05) while m RNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly lower that of GA group(P < 0.05).Conclusion: GA can inhibit the proliferation of bronchial smooth muscle cells and reduce the expression of inflammatory factors by inhibiting the phosphorylation of ERK1/2.
基金supported by Soft Science Foundation of Yongchuan District of Chongqing City(Grant No.YCSTC.2011BE5015)
文摘Objective:To explore the protective effect and its molecular mechanism of apoptosis signalregulating kinase 1(ASK1) inhibitor(GS-459679) on acetaminophen-induced liver injury in mice.Methods:The model of liver injury was established by administration of acetaminophen(APAP)(300 mg/kg,i.p.) on C57BL/6 mice.Forty-eight male C57BL/6 mice were randomly divided into four groups,consisting of control group,GS group(GS-459679,30 mg/kg,i.p.),APAPinduced group,and GS combined with APAP-induced group.For GS combined with APAPinduced group,mice were treated with GS 30 min prior to administration of APAP.After mice were euthanized at 6 h or 12 h.respectively,serum levels of alanine aminotransferase(ALT) and aspartate aminotransferase(AST) were analyzed,and mRNA levels of TNF- α,IL-6 and IL-1βwere tested.The activity of glutathione(GSH),oxidized GSH(GSSG) and malondialdehyde were quantified.In addition,ASK1,P-ASK1,JNK and P-JNK protein levels were tested in all groups.Results:The ASK1 and P-ASK1 levels were up-regulated in APAP-induced group.Compared to the control group,serum levels of ALT and AST.and mRNA levels of TNF- a,IL-6 and IL-1(3were increased in APAP-induced group.Meanwhile,the levels of MAD and GSSG.and the ratio of GSSG/GSH were higher and the JNK was activatedin APAP-induced group compared with that in control group.However,compared to APAP-induced group,GS combined with APAP-induced group displayed a decrease of protein expression levels of ASK 1,P-ASKI and P-JNK,a reduction of serum levels of ALT and AST,a decrease in TNF- a.IL-6 and IL-1(3 mRNA levels,and a low ration of GSSG/GSH.Conclusions:GS-459679 treatment effectively down-regulates ASK1 and P-ASK 1 expression.Addition of GS-459679 decreases the generation of liver metabolites and inflammatory factors,reduces oxidative stress reaction,inhibits JNK activation,and then protects the responsiveness to APAP-induced liver injury.
基金Shanghai Medical Key Discipline Construction Foundation(05-Ⅲ-005-017).
文摘Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-regulated kinase(ERK)pathway is thought to increase cell proliferation and to protect cells from apoptosis.The aim of the study was to investigate the correlation between the ERK1/2 signaling pathway and XAF1 in colon cancer.Methods:Four human colon cancer cell lines,HCT1116 and Lovo(wildtype p53),DLD1 and SW1116(mutant p53),were used.Lovo stable transfectants with XAF1 sense and antisense were established.The effects of dominant-negative MEK1(DN-MEK1)and MEK-specific inhibitor U0126 on the ERK signaling pathway and expression of XAF1 and XIAP proteins were determined.The transcription activity of core XAF1 promoter was assessed by dual luciferase reporter assay.Cell proliferation was measured by MTT assay.Apoptosis was determined by Hoechst 33258 staining.Results:U0126 increased the expression of XAF1 in a time-and dose-dependent manner.A similar result was obtained in cells transfected with DN-MEK1 treatment.Conversely,the expression of XIAP was down-regulated.Activity of the putative promoter of the XAF1 gene was significantly increased by U0126 treatment and DN-MEK1 transient transfection.rhEGF-stimulated phosphorylation of ERK appeared to have little or no effect on XAF1 expression.Overexpression of XAF1 was more sensitive to U0126-induced apoptosis,whereas down-regulation of XAF1 by antisense reversed U0126-induced inhibition of cell proliferation.Conclusions:XAF1 expression was up-regulated by inhibition of the ERK1/2 pathway through transcriptional regulation,which required de novo protein synthesis.The results suggest that XAF1 mediates apoptosis induced by the ERK1/2 pathway in colon cancer.
基金grants fromthe Chinese Academy of Sciences (No. KJ951-BI608), the National Natural Sciences FOundation ofChina (No. 39625007 and
文摘We reported in this manuscript that TGF-beta1 induces apoptosis in AML12 murine hepatocytes, which is associated with the activation of p38 MAPK signaling pathway. SB202190, a specific inhibitor of p38 MAPK, strongly inhibited the TGF-beta1-induced apoptosis and PAI-1 promoter activity. Treatment of cells with TGF-beta1 activates p38. Furthermore, over-expression of dominant negative mutant p38 also reduced the TGF-beta1-induced apoptosis. The data indicate that the activation of p38 is involved in TGF-beta1-mediated gene expression and apoptosis.
基金Supported by Research grants from Merck KGaA,Darmstadt,Germany,to Schulze-Bergkamen H
文摘AIM:To analyze the effect of chemotherapeutic drugs and specific kinase inhibitors,in combination with the death receptor ligand tumor necrosis factor-related apoptosis inducing ligand(TRAIL),on overcoming TRAIL resistance in hepatocellular carcinoma(HCC)and to study the efficacy of agonistic TRAIL antibodies,as well as the commitment of antiapoptotic BCL-2 proteins, in TRAIL-induced apoptosis. METHODS:Surface expression of TRAIL receptors (TRAIL-R1-4)and expression levels of the antiapoptotic BCL-2 proteins MCL-1 and BCL-xL were analyzed by flow cytometry and Western blotting,respectively. Knock-down of MCL-1 and BCL-xL was performed by transfecting specific small interfering RNAs.HCC cellswere treated with kinase inhibitors and chemotherapeutic drugs.Apoptosis induction and cell viability were analyzed via flow cytometry and 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. RESULTS:TRAIL-R1 and-R2 were profoundly expressed on the HCC cell lines Huh7 and Hep-G2. However,treatment of Huh7 and Hep-G2 with TRAIL and agonistic antibodies only induced minor apoptosis rates.Apoptosis resistance towards TRAIL could be considerably reduced by adding the chemotherapeutic drugs 5-fluorouracil and doxorubicin as well as the kinase inhibitors LY294002[inhibition of phosphoinositol- 3-kinase(PI3K)],AG1478(epidermal growth factor receptor kinase),PD98059(MEK1),rapamycin(mam- malian target of rapamycin)and the multi-kinase inhibitor Sorafenib.Furthermore,the antiapoptotic BCL-2 proteins MCL-1 and BCL-xL play a major role in TRAIL resistance:knock-down by RNA interference increased TRAIL-induced apoptosis of HCC cells.Additionally, knock-down of MCL-1 and BCL-xL led to a significant sensitization of HCC cells towards inhibition of both c-Jun N-terminal kinase and PI3K.CONCLUSION:Our data identify the blockage of survival kinases,combination with chemotherapeutic drugs and targeting of antiapoptotic BCL-2 proteins as promising ways to overcome TRAIL resistance in HCC.
文摘A major problem which is poorly understood in the management of bladder cancer is low sensitivity to chemotherapy and high recurrence after transurethral resection. Insulin-like growth factor 1 receptor (IGF-1R) signaling plays a very important role in progression, invasion and metastasis of bladder cancer cells. In this study, we investigated whether IGF-1R was involved in the growth stimulating activity and drug resistance of bladder cancer cells. The results showed: The mRNAs of IGF-1, IGF-2 and IGF-1R were strongly expressed in serum-free cultured T24 cell line, whereas normal urothelial cells did not express these factors/receptors or only in trace levels; T24 cell responded far better to growth stimulation by IGF-1 than did normal urothelial cells; blockage of IGF1R by antisense oligodeoxynucleotide (ODN) significantly inhibited the growth of T24 cell and enhanced sensitivity and apoptosis of T24 cells to mitomycin (MMC). These results suggested that blockage of IGF-IR signaling might potentially contribute to the treatment of bladder cancer cells which are insensitive to chemotherapy.
文摘目的:通过对硫氧还蛋白(Trx)突变体与凋亡信号调节激酶-1(ASK1)结合能力的研究,揭示Trx的氨基酸位点与其抗氧化抗凋亡性的关系,进一步阐述Trx在细胞凋亡中的作用。方法:构建人类野生型Trx(pcDNA-hTrx-H is tag,TrxA)和人类Trx 49位突变体(pcDNA-hTrx-Y49F-H is tag,TrxB)及ASK1质粒(pCDNA-ASK1-HA tag)。用TrxA、TrxB质粒分别与ASK1质粒共转染入HEK-293A细胞。实验分为对照组(CON)、ASK1质粒转染组、TrxA+ASK1质粒共转染组及TrxB+ASK1质粒共转染组。于转染24 h后,裂解细胞,裂解细胞前20 m in加入不同浓度的过氧化氢。将裂解产物进行W estern b lot检测转染的结果,运用免疫共沉淀(co-immunoprec ip itation)法检测ASK1与Trx在过氧化物作用下解离的程度,采用TUNEL法及检测Caspase-3的活性法检测HEK-293A细胞的凋亡。结果:与ASK1转染组细胞的凋亡指数(73.8±6.93)%及Caspase-3活性[(69.3±3.57)nmol/(h.mg蛋白)]相比,TrxA+ASK1共转染组细胞的凋亡率(49.8±4.62)%明显减少,Caspase-3的活性降低[(51.4±3.61)nmol/(h.mg蛋白)],(P<0.05)。TrxB+ASK1共转染组的凋亡率(22.4±5.07)%更少,Caspase-3的活性降低更明显[(30.1±2.48)nmol/(h.mg蛋白)](P<0.01)。与TrxA+ASK1共转染组相比,TrxB+ASK1共转染组的细胞凋亡数及Caspase-3的活性下降更明显(P<0.05)。此外,在过氧化氢干预下,TrxB与ASK1的结合同TrxA与ASK1的结合相比较,前者更紧密。结论:Trx中第49位的酪氨酸突变为苯丙氨酸后,Trx与ASK1的结合能力增强,Trx抗凋亡的作用明显增加。说明Trx与ASK1的结合能力与Trx的氨基酸位点明显相关,进而可影响Trx抗细胞凋亡的能力。
