BACKGROUND Gastric cancer(GC)has become a serious threat to people's health.Accumulative evidence reveals that dysregulation of numerous microRNAs(miRNAs)has been found during malignant formation.So far,the role o...BACKGROUND Gastric cancer(GC)has become a serious threat to people's health.Accumulative evidence reveals that dysregulation of numerous microRNAs(miRNAs)has been found during malignant formation.So far,the role of microRNA-760(miR-760)in the development of GC is largely unknown.AIM To measure the expression level of miR-760 in GC and investigate its role in gastric tumorigenesis.METHODS Real-time quantitative polymerase chain reaction and Western blot analysis were used to measure the expression of miR-760 and G-protein-coupled receptor kinase interacting protein-1(GIT1).Cell growth was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)and cell colony formation assays.Apoptosis was assessed by flow cytometric analysis.The relationship between miR-760 and GIT1 was verified by luciferase reporter assay.RESULTS The results showed that the expression of miR-760 was decreased in GC and associated with poor clinical outcomes in GC patients.Furthermore,miR-760 restrained cell proliferation and cell colony formation and induced apoptosis in GC cells.In addition,miR-760 directly targeted GIT1 and negatively regulated its expression in GC.GIT1 was upregulated in GC and predicted a worse prognosis in GC patients.We also found that upregulation of GIT1 weakened the inhibitory CONCLUSION In conclusion,miR-760 targets GIT1 to inhibit cell growth and promote apoptosis in GC cells.Our data demonstrate that miR-760 may be a potential target for the treatment of GC.展开更多
目的:设计构建G蛋白偶联受体激酶结合蛋白1(G protein coupled receptor kinase interacting protein 1,GIT1)野生型(WT)及点突变型(Y293F)慢病毒载体,探讨293位点对GIT1功能的影响。方法:用PCR从小鼠cDNA文库中扩增GIT1-WT,将其连接到...目的:设计构建G蛋白偶联受体激酶结合蛋白1(G protein coupled receptor kinase interacting protein 1,GIT1)野生型(WT)及点突变型(Y293F)慢病毒载体,探讨293位点对GIT1功能的影响。方法:用PCR从小鼠cDNA文库中扩增GIT1-WT,将其连接到慢病毒载体PLJM-GFP中,构建质粒PLJM-GFP-GIT1-WT,测序鉴定。利用TaKaRa MutanBEST Kit试剂盒,对PLJM-GFP-GIT1-WT进行定点突变,构建质粒PLJM-GFP-GIT1-Y293F,测序鉴定。重组慢病毒载体转染包装细胞293T,获取病毒上清感染培养至第4代的小鼠成骨细胞。划痕愈合试验检测成骨细胞迁移能力的变化。结果:通过PCR鉴定、双酶切鉴定及测序鉴定,成功构建了PLJM-GFP-GIT1-WT与PLJM-GFP-GIT1-Y293F。划痕愈合试验观察,与PLJM-GFP-GIT1-WT相比,PLJM-GFP-GIT1-Y293F明显抑制成骨细胞迁移。结论:GIT1功能的正常发挥有赖于293位点适时的磷酸化。展开更多
The activation of the mitogen-activated protein(MAP) kinases extracellular signal-regulated kinase(ERK)1/2 was traditionally used as a readout of signaling of G protein-coupled receptors(GPCRs) via arrestins, as oppos...The activation of the mitogen-activated protein(MAP) kinases extracellular signal-regulated kinase(ERK)1/2 was traditionally used as a readout of signaling of G protein-coupled receptors(GPCRs) via arrestins, as opposed to conventional GPCR signaling via G proteins. Several recent studies using HEK293 cells where all G proteins were genetically ablated or inactivated, or both non-visual arrestins were knocked out, demonstrated that ERK1/2 phosphorylation requires G protein activity, but does not necessarily require the presence of non-visual arrestins. This appears to contradict the prevailing paradigm. Here we discuss these results along with the recent data on gene edited cells and arrestinmediated signaling. We suggest that there is no real controversy. G proteins might be involved in the activation of the upstream-most MAP3Ks, although in vivo most MAP3K activation is independent of heterotrimeric G proteins, being initiated by receptor tyrosine kinases and/or integrins. As far as MAP kinases are concerned, the best-established role of arrestins is scaffolding of the three-tiered cascades(MAP3K-MAP2 K-MAPK). Thus, it seems likely that arrestins, GPCRbound and free, facilitate the propagation of signals in these cascades, whereas signal initiation via MAP3K activation may be independent of arrestins. Different MAP3Ks are activated by various inputs, some of which are mediated by G proteins, particularly in cell culture, where we artificially prevent signaling by receptor tyrosine kinases and integrins, thereby favoring GPCR-induced signaling. Thus, there is no reason to change the paradigm: Arrestins and G proteins play distinct non-overlapping roles in cell signaling.展开更多
文摘BACKGROUND Gastric cancer(GC)has become a serious threat to people's health.Accumulative evidence reveals that dysregulation of numerous microRNAs(miRNAs)has been found during malignant formation.So far,the role of microRNA-760(miR-760)in the development of GC is largely unknown.AIM To measure the expression level of miR-760 in GC and investigate its role in gastric tumorigenesis.METHODS Real-time quantitative polymerase chain reaction and Western blot analysis were used to measure the expression of miR-760 and G-protein-coupled receptor kinase interacting protein-1(GIT1).Cell growth was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)and cell colony formation assays.Apoptosis was assessed by flow cytometric analysis.The relationship between miR-760 and GIT1 was verified by luciferase reporter assay.RESULTS The results showed that the expression of miR-760 was decreased in GC and associated with poor clinical outcomes in GC patients.Furthermore,miR-760 restrained cell proliferation and cell colony formation and induced apoptosis in GC cells.In addition,miR-760 directly targeted GIT1 and negatively regulated its expression in GC.GIT1 was upregulated in GC and predicted a worse prognosis in GC patients.We also found that upregulation of GIT1 weakened the inhibitory CONCLUSION In conclusion,miR-760 targets GIT1 to inhibit cell growth and promote apoptosis in GC cells.Our data demonstrate that miR-760 may be a potential target for the treatment of GC.
文摘目的:设计构建G蛋白偶联受体激酶结合蛋白1(G protein coupled receptor kinase interacting protein 1,GIT1)野生型(WT)及点突变型(Y293F)慢病毒载体,探讨293位点对GIT1功能的影响。方法:用PCR从小鼠cDNA文库中扩增GIT1-WT,将其连接到慢病毒载体PLJM-GFP中,构建质粒PLJM-GFP-GIT1-WT,测序鉴定。利用TaKaRa MutanBEST Kit试剂盒,对PLJM-GFP-GIT1-WT进行定点突变,构建质粒PLJM-GFP-GIT1-Y293F,测序鉴定。重组慢病毒载体转染包装细胞293T,获取病毒上清感染培养至第4代的小鼠成骨细胞。划痕愈合试验检测成骨细胞迁移能力的变化。结果:通过PCR鉴定、双酶切鉴定及测序鉴定,成功构建了PLJM-GFP-GIT1-WT与PLJM-GFP-GIT1-Y293F。划痕愈合试验观察,与PLJM-GFP-GIT1-WT相比,PLJM-GFP-GIT1-Y293F明显抑制成骨细胞迁移。结论:GIT1功能的正常发挥有赖于293位点适时的磷酸化。
基金Supported by National Institutes of Health RO1 grants,No.EY011500National Institutes of Health R35 grants,No.GM122491Cornelius Vanderbilt Endowed Chair(Vanderbilt University),No.NS065868(to Gurevich VV)and No.DA030103(to Gurevich EV)
文摘The activation of the mitogen-activated protein(MAP) kinases extracellular signal-regulated kinase(ERK)1/2 was traditionally used as a readout of signaling of G protein-coupled receptors(GPCRs) via arrestins, as opposed to conventional GPCR signaling via G proteins. Several recent studies using HEK293 cells where all G proteins were genetically ablated or inactivated, or both non-visual arrestins were knocked out, demonstrated that ERK1/2 phosphorylation requires G protein activity, but does not necessarily require the presence of non-visual arrestins. This appears to contradict the prevailing paradigm. Here we discuss these results along with the recent data on gene edited cells and arrestinmediated signaling. We suggest that there is no real controversy. G proteins might be involved in the activation of the upstream-most MAP3Ks, although in vivo most MAP3K activation is independent of heterotrimeric G proteins, being initiated by receptor tyrosine kinases and/or integrins. As far as MAP kinases are concerned, the best-established role of arrestins is scaffolding of the three-tiered cascades(MAP3K-MAP2 K-MAPK). Thus, it seems likely that arrestins, GPCRbound and free, facilitate the propagation of signals in these cascades, whereas signal initiation via MAP3K activation may be independent of arrestins. Different MAP3Ks are activated by various inputs, some of which are mediated by G proteins, particularly in cell culture, where we artificially prevent signaling by receptor tyrosine kinases and integrins, thereby favoring GPCR-induced signaling. Thus, there is no reason to change the paradigm: Arrestins and G proteins play distinct non-overlapping roles in cell signaling.
