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
目的探索CX3CR1对创伤性骨髓炎大鼠骨骼肌微纤维、ERK/MAPK信号通路及炎症反应的影响。方法选取30只SPF级SD雄性大鼠,依据随机数字表法分为健康组、模型组、CX3CR1抑制组,每组10只。除健康组外,其余各组均建立创伤性骨髓炎模型。其中健...目的探索CX3CR1对创伤性骨髓炎大鼠骨骼肌微纤维、ERK/MAPK信号通路及炎症反应的影响。方法选取30只SPF级SD雄性大鼠,依据随机数字表法分为健康组、模型组、CX3CR1抑制组,每组10只。除健康组外,其余各组均建立创伤性骨髓炎模型。其中健康组、模型组大鼠均每日常规腹腔注射生理盐水,CX3CR1干预组向残腔内注射CX3CR1中和抗体进行处理。采用ELISA法检测血清中IL-6、IL-10、IL-1β、TGF-β水平,应用改良X线Norden评分检测骨骼肌微纤维,HE染色观察病理变化,免疫印迹及PCR检测股骨组织中细胞外信号调节蛋白激酶(Extracellular regulated protein kinase,ERK1/2)、丝裂原活化蛋白激酶(Mitogen activated protein kinase,MAPK)蛋白及mRNA表达。结果与健康组比较,模型组TGF-β、IL-1β、IL-10、IL-6等炎症因子含量均升高(P<0.05);与模型组比较,CX3CR1抑制组炎症因子含量降低(P<0.05)。与健康组比较,模型组随时间推移X线Norden评分升高(P<0.05);与模型组比较,CX3CR1抑制组X线Norden评分降低(P<0.05)。HE染色显示,健康组骨质完好;模型组可见大量炎性细胞浸润、灶性脓肿及坏死灶;CX3CR1抑制组大鼠的骨质明显改善,炎症反应降低。与健康组比较,模型组ERK1/2、MAPK蛋白及mRNA表达升高(P<0.05);与模型组比较,CX3CR1抑制组ERK1/2、MAPK蛋白及mRNA表达降低(P<0.05)。结论抑制CX3CR1可改善创伤性骨髓炎大鼠的疾病反应,可能与降低炎症反应、ERK/MAPK信号通路以及改善骨骼肌微纤维相关。展开更多
Overexpression of receptor-interacting protein 140（RIP140） promotes neuronal differentiation of N2 a cells via extracellular regulated kinase 1/2（ERK1/2） signaling.However,involvement of RIP140 in human neural dif...Overexpression of receptor-interacting protein 140（RIP140） promotes neuronal differentiation of N2 a cells via extracellular regulated kinase 1/2（ERK1/2） signaling.However,involvement of RIP140 in human neural differentiation remains unclear.We found both RIP140 and ERK1/2 expression increased during neural differentiation of H1 human embryonic stem cells.Moreover,RIP140 negatively correlated with stem cell markers Oct4 and Sox2 during early stages of neural differentiation,and positively correlated with the neural stem cell marker Nestin during later stages.Thus,ERK1/2 signaling may provide the molecular mechanism by which RIP140 takes part in neural differentiation to eventually affect the number of neurons produced.展开更多
Background: The mitogen-activated extracellular signal-regulated kinase 1/2(MEK1/2) inhibitor trametinib has shown promising therapeutic effects on melanoma, but its efficacy on colorectal cancer(CRC) is limited. Synt...Background: The mitogen-activated extracellular signal-regulated kinase 1/2(MEK1/2) inhibitor trametinib has shown promising therapeutic effects on melanoma, but its efficacy on colorectal cancer(CRC) is limited. Synthetic lethality arises with a combination of two or more separate gene mutations that causes cell death, whereas individual mutations keep cells alive. This study aimed to identify the genes responsible for resistance to trametinib in CRC cells,using a synthetic lethal short hairpin RNA(shRNA) screening approach.Methods: We infected HT29 cells with a pooled lentiviral shRNA library and applied next-generation sequencing to identify shRNAs with reduced abundance after 8-day treatment of 20 nmol/L trametinib. HCT116 and HT29 cells were used in validation studies. Stable ring finger protein 183(RNF183)-overexpressing cell lines were generated by pcDNA4-myc/his-RNF183 transfection. Stable RNF 183-knockdown cell lines were generated by infection of lentiviruses that express RNF183 shRNA, and small interference RNA(siRNA) was used to knock down RNF183 transiently.Quantitative real-time PCR was used to determine the mRNA expression. Western blotting, immunohistochemical analysis, and enzyme-linked immunosorbent assay(ELISA) were used to evaluate the protein abundance. MTT assay,colony formation assay, and subcutaneous xenograft tumor growth model were used to evaluate cell proliferation.Results: In the primary screening, we found that the abundance of RNF183 shRNA was markedly reduced after treatment with trametinib. Trametinib induced the expression of RNF183, which conferred resistance to drug-induced cell growth repression and apoptotic and non-apoptotic cell deaths. Moreover, interleukin-8(IL-8) was a downstream gene of RNF183 and was required for the function of RNF183 in facilitating cell growth. Additionally, elevated RNF183 expression partly reduced the inhibitory effect of trametinib on IL-8 expression. Finally, xenograft tumor model showed the synergism of RNF183 knockdown and trametinib in repressing the growth of CRC cells in vivo.Conclusion: The RNF183-IL-8 axis is responsible for the resistance of CRC cells to the MEK1/2 inhibitor trametinib and may serve as a candidate target for combined therapy for CRC.展开更多
Objective： BCR/ABL oncoprotein-expression is associated with uncontrolled cell growth. Sphingosine kinase 1 （SPK1） regulates the production of sphingosine 1-phosphate （S1P）, a key lipid signal molecular in cell p...Objective： BCR/ABL oncoprotein-expression is associated with uncontrolled cell growth. Sphingosine kinase 1 （SPK1） regulates the production of sphingosine 1-phosphate （S1P）, a key lipid signal molecular in cell proliferation and survival. The objective of this study was to elucidate the roles of S1P and its receptors in bcr/abl positive chronic myeloid leukemia （CML） cells. Methods： The expressions of SIP receptors： S1P1, S1P2 and S1P3 in CML cells were detected by RT-PCR. SPK1 expression, activity and extracellular S1P were determined in ECV304 and HL-60 cells which were transfected with bcr/abl gene. To elucidate the relationship between the BCR/ABL, ERK/MAPK （extracellular signal-regulated kinase/mitogen-activated protein kinase）, SPK/S 1P and S 1P/S 1 P2 signal pathways, bcr/abl positive CML cell line K562 was treated with STI571, PD98059, N,N-dimethyl sphingosine （DMS） and JTE-013. Results： Retrovirus-mediated overexpression of bcr/abl gene in ECV304 and HL-60 cells resulted in upregulation of the expression, activity of SPK1 and increase of the secretion of SIP, whereas treatment of STI571 and PD98059 decreased the BCR/ABL-induced S1P secretion. Treatment of DMS reduced S1P secretion and P42/44MAPK phosphorylation. S1P2-selective antagonist JTE-013 could also decrease P42/44MAPK phosphorylation. Conclusion： These results suggest that BCR/ABL up-regulates extracellular sphingosine 1-phosphate through sphingosine kinase 1 and there is cross-talk between SPK1/S1P/S1P2 and P42/44MAPK in bcr/abl positive CML cells.展开更多
Objective To investigate the signaling pathway through testing the effects of dexamethasone (Dex) on the activation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and p38 kinase (p38) in HO-8910...Objective To investigate the signaling pathway through testing the effects of dexamethasone (Dex) on the activation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and p38 kinase (p38) in HO-8910 cells.Methods Activation of the ERK1/2 and p38 was detected by Western blotting using the antibodies against the total ERK1/2 and p38 mitogen-activated protein kinases (MAPKs) protein and the phosphorylated forms of them. Results Dex could suppress the activation of ERK1/2, while enhance the activation of p38 rapidly and strongly in a dose- and time- dependent manner. Neither effect could be blocked by RU486, the antagonist of glucocorticoid receptor (GR).Conclusion Dex has rapid effects on the activation of ERK1/2 and p38, and these effects are not mediated by GR.展开更多
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.
文摘目的探索CX3CR1对创伤性骨髓炎大鼠骨骼肌微纤维、ERK/MAPK信号通路及炎症反应的影响。方法选取30只SPF级SD雄性大鼠,依据随机数字表法分为健康组、模型组、CX3CR1抑制组,每组10只。除健康组外,其余各组均建立创伤性骨髓炎模型。其中健康组、模型组大鼠均每日常规腹腔注射生理盐水,CX3CR1干预组向残腔内注射CX3CR1中和抗体进行处理。采用ELISA法检测血清中IL-6、IL-10、IL-1β、TGF-β水平,应用改良X线Norden评分检测骨骼肌微纤维,HE染色观察病理变化,免疫印迹及PCR检测股骨组织中细胞外信号调节蛋白激酶(Extracellular regulated protein kinase,ERK1/2)、丝裂原活化蛋白激酶(Mitogen activated protein kinase,MAPK)蛋白及mRNA表达。结果与健康组比较,模型组TGF-β、IL-1β、IL-10、IL-6等炎症因子含量均升高(P<0.05);与模型组比较,CX3CR1抑制组炎症因子含量降低(P<0.05)。与健康组比较,模型组随时间推移X线Norden评分升高(P<0.05);与模型组比较,CX3CR1抑制组X线Norden评分降低(P<0.05)。HE染色显示,健康组骨质完好;模型组可见大量炎性细胞浸润、灶性脓肿及坏死灶;CX3CR1抑制组大鼠的骨质明显改善,炎症反应降低。与健康组比较,模型组ERK1/2、MAPK蛋白及mRNA表达升高(P<0.05);与模型组比较,CX3CR1抑制组ERK1/2、MAPK蛋白及mRNA表达降低(P<0.05)。结论抑制CX3CR1可改善创伤性骨髓炎大鼠的疾病反应,可能与降低炎症反应、ERK/MAPK信号通路以及改善骨骼肌微纤维相关。
基金supported by the National Natural Science Foundation of China,No.31340024
文摘Overexpression of receptor-interacting protein 140（RIP140） promotes neuronal differentiation of N2 a cells via extracellular regulated kinase 1/2（ERK1/2） signaling.However,involvement of RIP140 in human neural differentiation remains unclear.We found both RIP140 and ERK1/2 expression increased during neural differentiation of H1 human embryonic stem cells.Moreover,RIP140 negatively correlated with stem cell markers Oct4 and Sox2 during early stages of neural differentiation,and positively correlated with the neural stem cell marker Nestin during later stages.Thus,ERK1/2 signaling may provide the molecular mechanism by which RIP140 takes part in neural differentiation to eventually affect the number of neurons produced.
基金supported by the National Natural Science Foundation of China(Nos.81672744,81472252)Science and Technology Project of Guangdong Province(No.2016A020217007)Guangdong Esophageal Cancer Institute(No.M201606)
文摘Background: The mitogen-activated extracellular signal-regulated kinase 1/2(MEK1/2) inhibitor trametinib has shown promising therapeutic effects on melanoma, but its efficacy on colorectal cancer(CRC) is limited. Synthetic lethality arises with a combination of two or more separate gene mutations that causes cell death, whereas individual mutations keep cells alive. This study aimed to identify the genes responsible for resistance to trametinib in CRC cells,using a synthetic lethal short hairpin RNA(shRNA) screening approach.Methods: We infected HT29 cells with a pooled lentiviral shRNA library and applied next-generation sequencing to identify shRNAs with reduced abundance after 8-day treatment of 20 nmol/L trametinib. HCT116 and HT29 cells were used in validation studies. Stable ring finger protein 183(RNF183)-overexpressing cell lines were generated by pcDNA4-myc/his-RNF183 transfection. Stable RNF 183-knockdown cell lines were generated by infection of lentiviruses that express RNF183 shRNA, and small interference RNA(siRNA) was used to knock down RNF183 transiently.Quantitative real-time PCR was used to determine the mRNA expression. Western blotting, immunohistochemical analysis, and enzyme-linked immunosorbent assay(ELISA) were used to evaluate the protein abundance. MTT assay,colony formation assay, and subcutaneous xenograft tumor growth model were used to evaluate cell proliferation.Results: In the primary screening, we found that the abundance of RNF183 shRNA was markedly reduced after treatment with trametinib. Trametinib induced the expression of RNF183, which conferred resistance to drug-induced cell growth repression and apoptotic and non-apoptotic cell deaths. Moreover, interleukin-8(IL-8) was a downstream gene of RNF183 and was required for the function of RNF183 in facilitating cell growth. Additionally, elevated RNF183 expression partly reduced the inhibitory effect of trametinib on IL-8 expression. Finally, xenograft tumor model showed the synergism of RNF183 knockdown and trametinib in repressing the growth of CRC cells in vivo.Conclusion: The RNF183-IL-8 axis is responsible for the resistance of CRC cells to the MEK1/2 inhibitor trametinib and may serve as a candidate target for combined therapy for CRC.
基金supported by the National Natural Science Foundation of China (No. 30570782).
文摘Objective： BCR/ABL oncoprotein-expression is associated with uncontrolled cell growth. Sphingosine kinase 1 （SPK1） regulates the production of sphingosine 1-phosphate （S1P）, a key lipid signal molecular in cell proliferation and survival. The objective of this study was to elucidate the roles of S1P and its receptors in bcr/abl positive chronic myeloid leukemia （CML） cells. Methods： The expressions of SIP receptors： S1P1, S1P2 and S1P3 in CML cells were detected by RT-PCR. SPK1 expression, activity and extracellular S1P were determined in ECV304 and HL-60 cells which were transfected with bcr/abl gene. To elucidate the relationship between the BCR/ABL, ERK/MAPK （extracellular signal-regulated kinase/mitogen-activated protein kinase）, SPK/S 1P and S 1P/S 1 P2 signal pathways, bcr/abl positive CML cell line K562 was treated with STI571, PD98059, N,N-dimethyl sphingosine （DMS） and JTE-013. Results： Retrovirus-mediated overexpression of bcr/abl gene in ECV304 and HL-60 cells resulted in upregulation of the expression, activity of SPK1 and increase of the secretion of SIP, whereas treatment of STI571 and PD98059 decreased the BCR/ABL-induced S1P secretion. Treatment of DMS reduced S1P secretion and P42/44MAPK phosphorylation. S1P2-selective antagonist JTE-013 could also decrease P42/44MAPK phosphorylation. Conclusion： These results suggest that BCR/ABL up-regulates extracellular sphingosine 1-phosphate through sphingosine kinase 1 and there is cross-talk between SPK1/S1P/S1P2 and P42/44MAPK in bcr/abl positive CML cells.
文摘Objective To investigate the signaling pathway through testing the effects of dexamethasone (Dex) on the activation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and p38 kinase (p38) in HO-8910 cells.Methods Activation of the ERK1/2 and p38 was detected by Western blotting using the antibodies against the total ERK1/2 and p38 mitogen-activated protein kinases (MAPKs) protein and the phosphorylated forms of them. Results Dex could suppress the activation of ERK1/2, while enhance the activation of p38 rapidly and strongly in a dose- and time- dependent manner. Neither effect could be blocked by RU486, the antagonist of glucocorticoid receptor (GR).Conclusion Dex has rapid effects on the activation of ERK1/2 and p38, and these effects are not mediated by GR.
