Acetaminophen(APAP)overdose is a major cause of liver injury.Neural precursor cell expressed developmentally downregulated 4—1(NEDD4-1)is an E3 ubiquitin ligase that has been implicated in the pathogenesis of numerou...Acetaminophen(APAP)overdose is a major cause of liver injury.Neural precursor cell expressed developmentally downregulated 4—1(NEDD4-1)is an E3 ubiquitin ligase that has been implicated in the pathogenesis of numerous liver diseases;however,its role in APAP-induced liver injury(AILI)is unclear.Thus,this study aimed to investigate the role of NEDD4-1 in the pathogenesis of AILI.We found that NEDD4-1 was dramatically downregulated in response to APAP treatment in mouse livers and isolated mouse hepatocytes.Hepatocyte-specific NEDD4-1 knockout exacerbated APAP-induced mitochondrial damage and the resultant hepatocyte necrosis and liver injury,while hepatocyte-specific NEDD4-1 overexpression mitigated these pathological events both in vivo and in vitro.Additionally,hepatocyte NEDD4-1 deficiency led to marked accumulation of voltage-dependent anion channel 1(VDAC1)and increased VDAC1 oligomerization.Furthermore,VDAC1 knockdown alleviated AILI and weakened the exacerbation of AILI caused by hepatocyte NEDD4-1 deficiency.Mechanistically,NEDD4-1 was found to interact with the PPTY motif of VDAC1 through its WW domain and regulate K48-linked ubiquitination and degradation of VDAC1.Our present study indicates that NEDD4-1 is a suppressor of AILI and functions by regulating the degradation of VDAC1.展开更多
神经前体细胞表达发育性下调蛋白4(neural precursor cell expressed,developmentally down-regulated protein 4,NEDD4-1,部分文章也称NEDD4)是近年来才备受关注的肿瘤相关基因,属于E3 HECT(homologous to E6 associated protein C ter...神经前体细胞表达发育性下调蛋白4(neural precursor cell expressed,developmentally down-regulated protein 4,NEDD4-1,部分文章也称NEDD4)是近年来才备受关注的肿瘤相关基因,属于E3 HECT(homologous to E6 associated protein C terminus,E6蛋白c端同源基因)泛素连接酶NEDD4样家族成员。泛素连接酶,能够参与多种蛋白质的泛素化、溶酶体及蛋白酶体的降解、胞核-胞质转位等,间接影响不同恶性肿瘤的多种信号通路。随着大量NEDD4-1与肿瘤相关实验的不断深入,目前已发现其可通过调控细胞周期、癌细胞侵袭转移、拮抗耐药性等许多途径影响肿瘤的生物学行为。在消化系统肿瘤中,NEDD4-1主要通过PTEN/PI3K/AKT、TGF-β、Hippo、LDLRAD4等多条通路促进肝细胞癌的增殖、侵袭和迁移能力;在胰腺癌中发现,NEDD4-1在PI3K/AKT信号通路中发挥癌基因作用,但在与Myc-SIRT2所形成的信号环路中,却发挥抑癌基因的作用;在胃癌和结直肠癌中,NEDD4-1所参与的信号通路与其他消化系统肿瘤均不相同,NEDD4-1能独立于PTEN/PI3K/AKT通路而发挥促进胃癌恶化、转移(EGFR信号通路)和抑制结直肠癌肿瘤生长(WNT信号通路)的作用。NEDD4-1已经成为人们治愈肿瘤的热门研究方向。本文通过系统总结NEDD4-1在不同消化系统肿瘤中的功能、信号通路和潜在抑制剂等,进行探讨NEDD4-1与不同信号通路的关系,旨为临床在癌症治疗领域提供重要的参考数据。展开更多
Background： The E3 ubiquitin ligasc neural precursor cell expressed developmentally downregulated 4-1（N EDD4-1） negatively regulates phosphatase and tensin homolog deleted on chromosome 10 （PTEN） protein levels t...Background： The E3 ubiquitin ligasc neural precursor cell expressed developmentally downregulated 4-1（N EDD4-1） negatively regulates phosphatase and tensin homolog deleted on chromosome 10 （PTEN） protein levels through polyubiquitination and proteolysis, but its significance in lung cancer is still unclear. This study investigated the expression and the role of NEDD4-1 in tumor developnaent and chemosensitivity of lung adenocarcinoma （ADC）. Methods： We retrospectively investigated the expression and significance ofNEDD4-1, PTEN, and p-Akt proteins in 135 paired A DC and adjacent noncancerous tissue specimens using immunohistochemistry. Furthemaore, we evaluated the relationship between NEDD4-1 expression and clinicopathologic characteristics and prognosis. The effects of small interfering RNA against NEDD4-1 on proliferation and chemosensitivity were examined in A549 cells in vitro using 3- （4,5-dimethylthiazol-2-yl） -5-（3-carboxymethoxyphenyl） -2-（4-sulfophenyl）- 2H-tetrazoliunl method. The ability of migration and invasion ofA549 cells was tested by transwell assay. Moreover, reverse-transcription quantitative polymerase chain reaction and Western blotting analyses were used to determine the expression of NEDD4-1, PTEN, phosphoinositide 3-kinase （PI3K）/Akt activity, and its downstream target proteins. Results： NEDD4-1 protein was significantly upregulated in lung ADC tissues, whereas it was weak or negative in normal lung epithelial cells. The expression ofNEDD4-1 in ADC （78.5%, 106/135） was significantly much higher than that in adjacent normal lung tissue （ 13.3%, 29/135, P 〈 0.01）, and it was associated with lymph node metastasis, tumor-node-metastasis （TNM） stage, and chemotherapy resistance. PTEN expression was downregulated in lung ADC （60.7% vs. 100.0% in noncancerous specimens, P - 0.007）, and was negatively correlated with lymph node metastasis, histological variants, clinical stage, chemoresistance. In addition, expression of p-Akt in ADC tissues （71.1% 96/135） was much higher than that in adjacent lung epithelial cells （6.7%, 9/135, P 〈 0.01 ）. Kaplan-Meier and multivariate analysis demonstrated that expressions ofNEDD4-1 and PTEN were both independent risk factors for survival in patients with lung ADC. NEDD4-1 knockdown in vivo decreased proliferation, migration, and invasion and improved chemosensitivity to cisplatin and paclitaxel in A549 cells. NEDD4-1 knockdown also significantly enhanced PTEN expression and inhibited p-Akt activity and downstream target proteins. Conclusions： NEDD4-1 upregulation may contribute to the progression of lung ADC. NEDD4-1 may regulate the proliferation, invasion, migration, and chemoresistance of lung ADC cells through the P13K/Akt pathway, suggesting that it may be regarded as a therapeutic target for the treatment of lung ADC.展开更多
基金supported by the National Natural Science Foundation of China(Beijing,ChinaGrant Nos.32022084 and 32172927)。
文摘Acetaminophen(APAP)overdose is a major cause of liver injury.Neural precursor cell expressed developmentally downregulated 4—1(NEDD4-1)is an E3 ubiquitin ligase that has been implicated in the pathogenesis of numerous liver diseases;however,its role in APAP-induced liver injury(AILI)is unclear.Thus,this study aimed to investigate the role of NEDD4-1 in the pathogenesis of AILI.We found that NEDD4-1 was dramatically downregulated in response to APAP treatment in mouse livers and isolated mouse hepatocytes.Hepatocyte-specific NEDD4-1 knockout exacerbated APAP-induced mitochondrial damage and the resultant hepatocyte necrosis and liver injury,while hepatocyte-specific NEDD4-1 overexpression mitigated these pathological events both in vivo and in vitro.Additionally,hepatocyte NEDD4-1 deficiency led to marked accumulation of voltage-dependent anion channel 1(VDAC1)and increased VDAC1 oligomerization.Furthermore,VDAC1 knockdown alleviated AILI and weakened the exacerbation of AILI caused by hepatocyte NEDD4-1 deficiency.Mechanistically,NEDD4-1 was found to interact with the PPTY motif of VDAC1 through its WW domain and regulate K48-linked ubiquitination and degradation of VDAC1.Our present study indicates that NEDD4-1 is a suppressor of AILI and functions by regulating the degradation of VDAC1.
文摘神经前体细胞表达发育性下调蛋白4(neural precursor cell expressed,developmentally down-regulated protein 4,NEDD4-1,部分文章也称NEDD4)是近年来才备受关注的肿瘤相关基因,属于E3 HECT(homologous to E6 associated protein C terminus,E6蛋白c端同源基因)泛素连接酶NEDD4样家族成员。泛素连接酶,能够参与多种蛋白质的泛素化、溶酶体及蛋白酶体的降解、胞核-胞质转位等,间接影响不同恶性肿瘤的多种信号通路。随着大量NEDD4-1与肿瘤相关实验的不断深入,目前已发现其可通过调控细胞周期、癌细胞侵袭转移、拮抗耐药性等许多途径影响肿瘤的生物学行为。在消化系统肿瘤中,NEDD4-1主要通过PTEN/PI3K/AKT、TGF-β、Hippo、LDLRAD4等多条通路促进肝细胞癌的增殖、侵袭和迁移能力;在胰腺癌中发现,NEDD4-1在PI3K/AKT信号通路中发挥癌基因作用,但在与Myc-SIRT2所形成的信号环路中,却发挥抑癌基因的作用;在胃癌和结直肠癌中,NEDD4-1所参与的信号通路与其他消化系统肿瘤均不相同,NEDD4-1能独立于PTEN/PI3K/AKT通路而发挥促进胃癌恶化、转移(EGFR信号通路)和抑制结直肠癌肿瘤生长(WNT信号通路)的作用。NEDD4-1已经成为人们治愈肿瘤的热门研究方向。本文通过系统总结NEDD4-1在不同消化系统肿瘤中的功能、信号通路和潜在抑制剂等,进行探讨NEDD4-1与不同信号通路的关系,旨为临床在癌症治疗领域提供重要的参考数据。
基金This work was supported by a grant from the National Natural Science Foundation of China （No. 81402185）.
文摘Background： The E3 ubiquitin ligasc neural precursor cell expressed developmentally downregulated 4-1（N EDD4-1） negatively regulates phosphatase and tensin homolog deleted on chromosome 10 （PTEN） protein levels through polyubiquitination and proteolysis, but its significance in lung cancer is still unclear. This study investigated the expression and the role of NEDD4-1 in tumor developnaent and chemosensitivity of lung adenocarcinoma （ADC）. Methods： We retrospectively investigated the expression and significance ofNEDD4-1, PTEN, and p-Akt proteins in 135 paired A DC and adjacent noncancerous tissue specimens using immunohistochemistry. Furthemaore, we evaluated the relationship between NEDD4-1 expression and clinicopathologic characteristics and prognosis. The effects of small interfering RNA against NEDD4-1 on proliferation and chemosensitivity were examined in A549 cells in vitro using 3- （4,5-dimethylthiazol-2-yl） -5-（3-carboxymethoxyphenyl） -2-（4-sulfophenyl）- 2H-tetrazoliunl method. The ability of migration and invasion ofA549 cells was tested by transwell assay. Moreover, reverse-transcription quantitative polymerase chain reaction and Western blotting analyses were used to determine the expression of NEDD4-1, PTEN, phosphoinositide 3-kinase （PI3K）/Akt activity, and its downstream target proteins. Results： NEDD4-1 protein was significantly upregulated in lung ADC tissues, whereas it was weak or negative in normal lung epithelial cells. The expression ofNEDD4-1 in ADC （78.5%, 106/135） was significantly much higher than that in adjacent normal lung tissue （ 13.3%, 29/135, P 〈 0.01）, and it was associated with lymph node metastasis, tumor-node-metastasis （TNM） stage, and chemotherapy resistance. PTEN expression was downregulated in lung ADC （60.7% vs. 100.0% in noncancerous specimens, P - 0.007）, and was negatively correlated with lymph node metastasis, histological variants, clinical stage, chemoresistance. In addition, expression of p-Akt in ADC tissues （71.1% 96/135） was much higher than that in adjacent lung epithelial cells （6.7%, 9/135, P 〈 0.01 ）. Kaplan-Meier and multivariate analysis demonstrated that expressions ofNEDD4-1 and PTEN were both independent risk factors for survival in patients with lung ADC. NEDD4-1 knockdown in vivo decreased proliferation, migration, and invasion and improved chemosensitivity to cisplatin and paclitaxel in A549 cells. NEDD4-1 knockdown also significantly enhanced PTEN expression and inhibited p-Akt activity and downstream target proteins. Conclusions： NEDD4-1 upregulation may contribute to the progression of lung ADC. NEDD4-1 may regulate the proliferation, invasion, migration, and chemoresistance of lung ADC cells through the P13K/Akt pathway, suggesting that it may be regarded as a therapeutic target for the treatment of lung ADC.
