目的:探讨核蛋白样转录因子核受体亚家族2组E成员1(nuclear receptor subfamily 2 group E member 1,NR2E1)对儿童神经母细胞瘤细胞株IMR-32生长、分裂、增殖的影响。方法:应用LipofectamineTM2000将构建的针对核蛋白样转录因子NR2E1的s...目的:探讨核蛋白样转录因子核受体亚家族2组E成员1(nuclear receptor subfamily 2 group E member 1,NR2E1)对儿童神经母细胞瘤细胞株IMR-32生长、分裂、增殖的影响。方法:应用LipofectamineTM2000将构建的针对核蛋白样转录因子NR2E1的shiRNA质粒载体转染神经母细胞瘤细胞株IMR32,并通过细胞计数法观察细胞生长抑制效应,采用细胞免疫荧光染色检测神经母细胞瘤细胞株IMR32细胞分裂蛋白的表达。结果:核蛋白样转录因子NR2E1的shiRNA质粒转染神经母细胞瘤细胞株IMR32 48 h后,该细胞株生长缓慢;相关细胞核分裂蛋白表达受到明显的抑制。结论:核蛋白样转录因子NR2E1的shiRNA干扰质粒转染神经母细胞瘤细胞株IMR32后,抑制了神经母细胞瘤细胞IMR32的分裂和增殖。展开更多
AIM:To investigate the role of nuclear factor of activated T cell 2(NFAT2),the major NFAT protein in peripheral T cells,in sustained T cell activation and intractable inflammation in human ulcerative colitis(UC). METH...AIM:To investigate the role of nuclear factor of activated T cell 2(NFAT2),the major NFAT protein in peripheral T cells,in sustained T cell activation and intractable inflammation in human ulcerative colitis(UC). METHODS:We used two-dimensional gel-electrophoresis, immunohistochemistry,double immunohistochemical staining,and confocal microscopy to inspect the expression of NFAT2 in 107,15,48 and 5 cases of UC, Crohn's disease(CD),non-specific colitis,and 5 healthy individuals,respectively. RESULTS:Up-regulation with profound nucleo- translocation/activation of NFAT2 of lamina propria mononuclear cells(LPMC)of colonic mucosa was found specifically in the affected colonic mucosa from patients with UC,as compared to CD or NC(P<0.001,Kruskal- Wallis test).Nucleo-translocation/activation of NFAT2 primarily occurred in CD8+T,but was less prominent in CD4+T cells or CD20+B cells.It was strongly associated with the disease activity,including endoscopic stage (τ=0.2145,P=0.0281)and histologic grade(τ=0.4167, P<0.001). CONCLUSION:We disclose for the first time the nucleo-translocation/activatin of NFAT2 in lamina propria mononuclear cells in ulcerative colitis.Activation of NFAT2 was specific for ulcerative colitis and highly associated with disease activity.Since activation of NFAT2is implicated in an auto-regulatory positive feedback loop of sustained T-cell activation and NFAT proteins play key roles in the calcium/calcineurin signaling pathways,our results not only provide new insights into the mechanism for sustained intractable inflammation,but also suggest the calcium-calcineurin/NFAT pathway as a new therapeutic target for ulcerative colitis.展开更多
The nuclear factor-kappa B （NF-κB） transcription factor plays a critical role in diverse cellular processes associated with proliferation, cell death, development, as well as innate and adaptive immune responses. ...The nuclear factor-kappa B （NF-κB） transcription factor plays a critical role in diverse cellular processes associated with proliferation, cell death, development, as well as innate and adaptive immune responses. NF-κB is normally sequestered in the cytoplasm by a family of inhibitory proteins known as inhibitors of NF-κB （IκBs）. The signal pathways leading to the liberation and nuclear accumulation of NF-κB, which can be activated by a wide variety of stimuli, have been extensively studied in the past two decades. After gaining access to the nucleus, NF-κB must be actively regulated to execute its fundamental function as a transcription factor. Recent studies have highlighted the importance of nuclear signaling in the regulation of NF-κB transcriptional activity. A non-Rel subunit of NF-κB, ribosomal protein S3 （RPS3）, and numerous other nuclear regulators of NF-κB, including Akirin, Nurrl, SIRT6, and others, have recently been identified, unveiling novel and exciting layers of regulatory specificity for NF-κB in the nucleus. Further insights into the nuclear events that govern NF-κB function will deepen our understanding of the elegant control of its transcriptional activity and better inform the potential rational design of therapeutics for NF-κB-associated diseases.展开更多
It has been shown that oncoprotein p28GANK, which is consistently overexpressed in human hepatocellular carcinoma （HCC）, plays a critical role in tumorigenesis of HCC. However, the underlying mechanism remains uncle...It has been shown that oncoprotein p28GANK, which is consistently overexpressed in human hepatocellular carcinoma （HCC）, plays a critical role in tumorigenesis of HCC. However, the underlying mechanism remains unclear. Here, we demonstrated that p28GANK inhibits apoptosis in HCC cells induced by the endoplasmic reticulum （ER） stress. During ER stress, p28GANK enhances the unfolded protein response, promotes ER recovery from translational repression, and thereby facilitates cell＇s ability to cope with the stress conditions. Furthermore, p28GANK upregulates glucose-regulated protein 78 （GRP78）, a key ER chaperone protein, which subsequently enhances the ER folding capacity and promotes recovery from ER stress. We also demonstrated that p28GANK increases p38 mitogen-activated protein kinase and Akt phosphorylation, and inhibits nuclear factor kappa B （NF-κB） activation under ER stress, which in turn contributes to GRP78 upregulation. Taken together, our results indicate that p28GANK inhibits ER stress-induced apoptosis in HCC cells, at least in part, by enhancing the adaptive response and GRP78 expression. We propose that p28GANK has potential implications for HCC progression under the ER stress conditions.展开更多
Small GTP-binding proteins of the ADP-ribosylation fac-tor （Arf） family control various cell functional responses including protein transport and recycling between different cellular compartments, phagocytosis, prol...Small GTP-binding proteins of the ADP-ribosylation fac-tor （Arf） family control various cell functional responses including protein transport and recycling between different cellular compartments, phagocytosis, prolif-eration, cytoskeletal remodelling, and migration. The activity of Arfs is tightly regulated. GTPase-activating proteins （GAPs） inactivate Arfs by stimulating GTP hydrolysis, and guanine nucleotide exchange factors （GEFs） stimulate the conversion of inactive GDP-bound Arf to the active GTP-bound conformation. There is increasing evidence that Arf small GTPases contribute to cancer growth and invasion. Increased expression of Arf6 and of Arf-GEPs, or deregulation Arf-GAP functions have been correlated with enhanced invasive capacity of tumor cells and metastasis. The spatiotemporal spe-cifcity of Arf activation is dictated by their GEFs that integrate various signals in stimulated cells. Brefeldin A （BFA）, which inactivates a subset of Arf-GEFs, has been very useful for assessing the function of Golgi-localized Arfs. However, specifc inhibitors to investigate the individual function of BFA-sensitive and insensitive Arf-GEFs are lacking. In recent years, specifc screens have been developed, and new inhibitors with improved se-lectivity and potency to study cell functional responses regulated by BFA-sensitive and BFA-insensitive Arf pathways have been identified. These inhibitors have been instrumental for our understanding of the spa-tiotemporal activation of Arf proteins in cells and dem-onstrate the feasibility of developing small molecules interfering with Arf activation to prevent tumor invasion and metastasis.展开更多
文摘目的:探讨核蛋白样转录因子核受体亚家族2组E成员1(nuclear receptor subfamily 2 group E member 1,NR2E1)对儿童神经母细胞瘤细胞株IMR-32生长、分裂、增殖的影响。方法:应用LipofectamineTM2000将构建的针对核蛋白样转录因子NR2E1的shiRNA质粒载体转染神经母细胞瘤细胞株IMR32,并通过细胞计数法观察细胞生长抑制效应,采用细胞免疫荧光染色检测神经母细胞瘤细胞株IMR32细胞分裂蛋白的表达。结果:核蛋白样转录因子NR2E1的shiRNA质粒转染神经母细胞瘤细胞株IMR32 48 h后,该细胞株生长缓慢;相关细胞核分裂蛋白表达受到明显的抑制。结论:核蛋白样转录因子NR2E1的shiRNA干扰质粒转染神经母细胞瘤细胞株IMR32后,抑制了神经母细胞瘤细胞IMR32的分裂和增殖。
基金a grant from Chang Gung Memorial Hospital,No.CMRPG33074a grant from National Science Council,Taiwan
文摘AIM:To investigate the role of nuclear factor of activated T cell 2(NFAT2),the major NFAT protein in peripheral T cells,in sustained T cell activation and intractable inflammation in human ulcerative colitis(UC). METHODS:We used two-dimensional gel-electrophoresis, immunohistochemistry,double immunohistochemical staining,and confocal microscopy to inspect the expression of NFAT2 in 107,15,48 and 5 cases of UC, Crohn's disease(CD),non-specific colitis,and 5 healthy individuals,respectively. RESULTS:Up-regulation with profound nucleo- translocation/activation of NFAT2 of lamina propria mononuclear cells(LPMC)of colonic mucosa was found specifically in the affected colonic mucosa from patients with UC,as compared to CD or NC(P<0.001,Kruskal- Wallis test).Nucleo-translocation/activation of NFAT2 primarily occurred in CD8+T,but was less prominent in CD4+T cells or CD20+B cells.It was strongly associated with the disease activity,including endoscopic stage (τ=0.2145,P=0.0281)and histologic grade(τ=0.4167, P<0.001). CONCLUSION:We disclose for the first time the nucleo-translocation/activatin of NFAT2 in lamina propria mononuclear cells in ulcerative colitis.Activation of NFAT2 was specific for ulcerative colitis and highly associated with disease activity.Since activation of NFAT2is implicated in an auto-regulatory positive feedback loop of sustained T-cell activation and NFAT proteins play key roles in the calcium/calcineurin signaling pathways,our results not only provide new insights into the mechanism for sustained intractable inflammation,but also suggest the calcium-calcineurin/NFAT pathway as a new therapeutic target for ulcerative colitis.
文摘The nuclear factor-kappa B （NF-κB） transcription factor plays a critical role in diverse cellular processes associated with proliferation, cell death, development, as well as innate and adaptive immune responses. NF-κB is normally sequestered in the cytoplasm by a family of inhibitory proteins known as inhibitors of NF-κB （IκBs）. The signal pathways leading to the liberation and nuclear accumulation of NF-κB, which can be activated by a wide variety of stimuli, have been extensively studied in the past two decades. After gaining access to the nucleus, NF-κB must be actively regulated to execute its fundamental function as a transcription factor. Recent studies have highlighted the importance of nuclear signaling in the regulation of NF-κB transcriptional activity. A non-Rel subunit of NF-κB, ribosomal protein S3 （RPS3）, and numerous other nuclear regulators of NF-κB, including Akirin, Nurrl, SIRT6, and others, have recently been identified, unveiling novel and exciting layers of regulatory specificity for NF-κB in the nucleus. Further insights into the nuclear events that govern NF-κB function will deepen our understanding of the elegant control of its transcriptional activity and better inform the potential rational design of therapeutics for NF-κB-associated diseases.
文摘It has been shown that oncoprotein p28GANK, which is consistently overexpressed in human hepatocellular carcinoma （HCC）, plays a critical role in tumorigenesis of HCC. However, the underlying mechanism remains unclear. Here, we demonstrated that p28GANK inhibits apoptosis in HCC cells induced by the endoplasmic reticulum （ER） stress. During ER stress, p28GANK enhances the unfolded protein response, promotes ER recovery from translational repression, and thereby facilitates cell＇s ability to cope with the stress conditions. Furthermore, p28GANK upregulates glucose-regulated protein 78 （GRP78）, a key ER chaperone protein, which subsequently enhances the ER folding capacity and promotes recovery from ER stress. We also demonstrated that p28GANK increases p38 mitogen-activated protein kinase and Akt phosphorylation, and inhibits nuclear factor kappa B （NF-κB） activation under ER stress, which in turn contributes to GRP78 upregulation. Taken together, our results indicate that p28GANK inhibits ER stress-induced apoptosis in HCC cells, at least in part, by enhancing the adaptive response and GRP78 expression. We propose that p28GANK has potential implications for HCC progression under the ER stress conditions.
基金Supported by A Grant from the Canadian Institutes of Health Research(MOP-14790)to Bourgoin SG
文摘Small GTP-binding proteins of the ADP-ribosylation fac-tor （Arf） family control various cell functional responses including protein transport and recycling between different cellular compartments, phagocytosis, prolif-eration, cytoskeletal remodelling, and migration. The activity of Arfs is tightly regulated. GTPase-activating proteins （GAPs） inactivate Arfs by stimulating GTP hydrolysis, and guanine nucleotide exchange factors （GEFs） stimulate the conversion of inactive GDP-bound Arf to the active GTP-bound conformation. There is increasing evidence that Arf small GTPases contribute to cancer growth and invasion. Increased expression of Arf6 and of Arf-GEPs, or deregulation Arf-GAP functions have been correlated with enhanced invasive capacity of tumor cells and metastasis. The spatiotemporal spe-cifcity of Arf activation is dictated by their GEFs that integrate various signals in stimulated cells. Brefeldin A （BFA）, which inactivates a subset of Arf-GEFs, has been very useful for assessing the function of Golgi-localized Arfs. However, specifc inhibitors to investigate the individual function of BFA-sensitive and insensitive Arf-GEFs are lacking. In recent years, specifc screens have been developed, and new inhibitors with improved se-lectivity and potency to study cell functional responses regulated by BFA-sensitive and BFA-insensitive Arf pathways have been identified. These inhibitors have been instrumental for our understanding of the spa-tiotemporal activation of Arf proteins in cells and dem-onstrate the feasibility of developing small molecules interfering with Arf activation to prevent tumor invasion and metastasis.
