Previously, we reported that M-CSF induced monocyte survival through the activation of Akt, p38MAPK and Erk1/2 kinases. Here, we found that Src family kinases were upstream of these kinases and played a central role i...Previously, we reported that M-CSF induced monocyte survival through the activation of Akt, p38MAPK and Erk1/2 kinases. Here, we found that Src family kinases were upstream of these kinases and played a central role in regulating M-CSF-induced monocyte survival. We observed that M-CSF promoted c-Src activation in monocytes and MDMs in a time-dependent manner. Src inhibitors reduced M-CSF-mediated phosphorylation of the M-CSF receptor (M-CSFR), Akt, Erk1/2, and p38 MAPK. We also observed that Src directly phosphorylated the M-CSFR. Notably, the inhibitors blocked phosphorylation of specific tyrosine residues within the M-CSFR. We further demonstrated that the Src inhibitor, PP2, attenuated M-CSF-induced NF-κB activation and M-CSF-induced monocyte survival. These findings indicated that Src family kinases mediate monocyte survival through the regulation of receptor phosphorylation and modulation of downstream signaling events. Thus, we predict that targeting Src family kinases may have therapeutic implication in inflammatory diseases.展开更多
Epidermal growth factor receptor(EGFR) controls a wide range of cellular processes, and aberrant EGFR signaling as a result of receptor overexpression and/or mutation occurs in many types of cancer. Tumor cells in non...Epidermal growth factor receptor(EGFR) controls a wide range of cellular processes, and aberrant EGFR signaling as a result of receptor overexpression and/or mutation occurs in many types of cancer. Tumor cells in non-small cell lung cancer(NSCLC) patients that harbor EGFR kinase domain mutations exhibit oncogene addiction to mutant EGFR, which confers high sensitivity to tyrosine kinase inhibitors(TKIs). As patients invariably develop resistance to TKIs, it is important to delineate the cell biological basis of mutant EGFR-induced cellular transformation since components of these pathways can serve as alternate therapeutic targets to preempt or overcome resistance. NSCLC-associated EGFR mutants are constitutively-active and induce ligandindependent transformation in nonmalignant cell lines. Emerging data suggest that a number of factors are critical for the mutant EGFR-dependent tumorigenicity, and bypassing the effects of TKIs on these pathways promotes drug resistance. For example, activation of downstream pathways such as Akt, Erk, STAT3 and Src is critical for mutant EGFR-mediated biological processes. It is now well-established that the potency and spatiotemporal features of cellular signaling by receptor tyrosine kinases such as EGFR, as well as the specific pathways activated, is determined by the nature of endocytic traffic pathways through which the active receptors traverse. Recent evidence indicates that NSCLCassociated mutant EGFRs exhibit altered endocytic trafficking and they exhibit reduced Cbl ubiquitin ligasemediated lysosomal downregulation. More recent work has shown that mutant EGFRs undergo ligand-independent traffic into the endocytic recycling compartment, a behavior that plays a key role in Src pathway activation and oncogenesis. These studies are beginning to delineate the close nexus between signaling and endocytic traffic of EGFR mutants as a key driver of oncogenicprocesses. Therefore, in this review, we will discuss the links between mutant EGFR signaling and endocytic properties, and introduce potential mechanisms by which altered endocytic properties of mutant EGFRs may alter signaling and vice versa as well as their implications for NSCLC therapy.展开更多
目的探讨脑缺血再灌注后神经元突触后膜NMDA受体发生迁移重塑的机制。方法实验使用脑缺血再灌注Wistar大鼠模型,分为无缺血再灌注对照组(Ctrl),缺血再灌注0.5h组(I/R-0.5h),缺血再灌注4h组(I/R-4h),缺血再灌注24h组(I/R-24h)。再灌注时...目的探讨脑缺血再灌注后神经元突触后膜NMDA受体发生迁移重塑的机制。方法实验使用脑缺血再灌注Wistar大鼠模型,分为无缺血再灌注对照组(Ctrl),缺血再灌注0.5h组(I/R-0.5h),缺血再灌注4h组(I/R-4h),缺血再灌注24h组(I/R-24h)。再灌注时间达到后将脑组织取出,并制成脑组织匀浆液(HOM),利用差速离心法分离突触后膜组分(SYN)和突触外膜组分(EXTRA),通过Western Blot分析Src蛋白激酶的表达分布及NMDA受体NR2A和NR2B的表达分布。结果 Western Blot分析发现,脑缺血再灌注0.5h后,突触后膜组分Src蛋白激酶出现超激活状态(P<0.01),NR2A和NR2B在突触外膜组分中的表达显著降低(P<0.01),而NR2A和NR2B在突触后膜组分中的表达升高(P<0.05);在再灌注4h后,Src蛋白激酶激活程度更加明显(P<0.01),NR2A和NR2B在突触外膜组分中的表达仍显著下降(P<0.05),但NR2A和NR2B在突触后膜组分中却出现不同程度的下降。结论脑缺血再灌注后神经元突触后膜出现Src蛋白激酶超激活状态,并介导NMDA受体NR2A和NR2B的表达分布出现重塑性,NMDA受体从突触周膜向突触后膜转移聚集。展开更多
文摘Previously, we reported that M-CSF induced monocyte survival through the activation of Akt, p38MAPK and Erk1/2 kinases. Here, we found that Src family kinases were upstream of these kinases and played a central role in regulating M-CSF-induced monocyte survival. We observed that M-CSF promoted c-Src activation in monocytes and MDMs in a time-dependent manner. Src inhibitors reduced M-CSF-mediated phosphorylation of the M-CSF receptor (M-CSFR), Akt, Erk1/2, and p38 MAPK. We also observed that Src directly phosphorylated the M-CSFR. Notably, the inhibitors blocked phosphorylation of specific tyrosine residues within the M-CSFR. We further demonstrated that the Src inhibitor, PP2, attenuated M-CSF-induced NF-κB activation and M-CSF-induced monocyte survival. These findings indicated that Src family kinases mediate monocyte survival through the regulation of receptor phosphorylation and modulation of downstream signaling events. Thus, we predict that targeting Src family kinases may have therapeutic implication in inflammatory diseases.
基金Supported by the NIH grant to Band H,No.CA99163,CA87986,CA105489 and CA116552a Department of Defense grant to Band H,No.W81WH-11-1-0167+4 种基金the NIH grant to Band V,No.CA96844 and CA144027Department of Defense grant to Band V,No.W81XWH-07-1-0351 and W81XWH-11-1-0171the Nebraska Department of Health and Human Services LB-506 grant to Band H,No.2014-01the NCI Core Support Grant to the UNMC Buffett Cancer CenterBielecki TA was a predoctoral trainee under the NCI Institutional Cancer Biology Training Grant,No.CA009476
文摘Epidermal growth factor receptor(EGFR) controls a wide range of cellular processes, and aberrant EGFR signaling as a result of receptor overexpression and/or mutation occurs in many types of cancer. Tumor cells in non-small cell lung cancer(NSCLC) patients that harbor EGFR kinase domain mutations exhibit oncogene addiction to mutant EGFR, which confers high sensitivity to tyrosine kinase inhibitors(TKIs). As patients invariably develop resistance to TKIs, it is important to delineate the cell biological basis of mutant EGFR-induced cellular transformation since components of these pathways can serve as alternate therapeutic targets to preempt or overcome resistance. NSCLC-associated EGFR mutants are constitutively-active and induce ligandindependent transformation in nonmalignant cell lines. Emerging data suggest that a number of factors are critical for the mutant EGFR-dependent tumorigenicity, and bypassing the effects of TKIs on these pathways promotes drug resistance. For example, activation of downstream pathways such as Akt, Erk, STAT3 and Src is critical for mutant EGFR-mediated biological processes. It is now well-established that the potency and spatiotemporal features of cellular signaling by receptor tyrosine kinases such as EGFR, as well as the specific pathways activated, is determined by the nature of endocytic traffic pathways through which the active receptors traverse. Recent evidence indicates that NSCLCassociated mutant EGFRs exhibit altered endocytic trafficking and they exhibit reduced Cbl ubiquitin ligasemediated lysosomal downregulation. More recent work has shown that mutant EGFRs undergo ligand-independent traffic into the endocytic recycling compartment, a behavior that plays a key role in Src pathway activation and oncogenesis. These studies are beginning to delineate the close nexus between signaling and endocytic traffic of EGFR mutants as a key driver of oncogenicprocesses. Therefore, in this review, we will discuss the links between mutant EGFR signaling and endocytic properties, and introduce potential mechanisms by which altered endocytic properties of mutant EGFRs may alter signaling and vice versa as well as their implications for NSCLC therapy.
文摘目的探讨脑缺血再灌注后神经元突触后膜NMDA受体发生迁移重塑的机制。方法实验使用脑缺血再灌注Wistar大鼠模型,分为无缺血再灌注对照组(Ctrl),缺血再灌注0.5h组(I/R-0.5h),缺血再灌注4h组(I/R-4h),缺血再灌注24h组(I/R-24h)。再灌注时间达到后将脑组织取出,并制成脑组织匀浆液(HOM),利用差速离心法分离突触后膜组分(SYN)和突触外膜组分(EXTRA),通过Western Blot分析Src蛋白激酶的表达分布及NMDA受体NR2A和NR2B的表达分布。结果 Western Blot分析发现,脑缺血再灌注0.5h后,突触后膜组分Src蛋白激酶出现超激活状态(P<0.01),NR2A和NR2B在突触外膜组分中的表达显著降低(P<0.01),而NR2A和NR2B在突触后膜组分中的表达升高(P<0.05);在再灌注4h后,Src蛋白激酶激活程度更加明显(P<0.01),NR2A和NR2B在突触外膜组分中的表达仍显著下降(P<0.05),但NR2A和NR2B在突触后膜组分中却出现不同程度的下降。结论脑缺血再灌注后神经元突触后膜出现Src蛋白激酶超激活状态,并介导NMDA受体NR2A和NR2B的表达分布出现重塑性,NMDA受体从突触周膜向突触后膜转移聚集。
