Krüppel-like factor(KLF) family proteins are transcription factors that regulate numerous cellular functions, such as cell proliferation, differentiation, and cell death. Posttranslational modification of KLF pro...Krüppel-like factor(KLF) family proteins are transcription factors that regulate numerous cellular functions, such as cell proliferation, differentiation, and cell death. Posttranslational modification of KLF proteins is important for their transcriptional activities and biological functions. One KLF family member with important roles in cell proliferation and tumorigenesis is KLF5. The function of KLF5 is tightly controlled by post-translational modifications, including SUMOylation, phosphorylation, and ubiquitination. Recent studies from our lab and others' have demonstrated that the tumor suppressor FBW7 is an essential E3 ubiquitin ligase that targets KLF5 for ubiquitination and degradation. KLF5 contains functional Cdc4 phospho-degrons(CPDs), which are required for its interaction with FBW7. Mutation of CPDs in KLF5 blocks the ubiquitination and degradation of KLF5 by FBW7. The protein kinase Glycogen synthase kinase 3β is involved in the phosphorylation of KLF5 CPDs. In both cancer cell lines and mousemodels, it has been shown that FBW7 regulates the expression of KLF5 target genes through the modulation of KLF5 stability. In this review, we summarize the current progress on delineating FBW7-mediated KLF5 ubiquitination and degradation.展开更多
FBW7(F-box and WD repeat domain-containing7)是F-box蛋白家族成员,为SCF(SKP1-CUL1-F-box)型泛素连接酶的靶蛋白识别组分。FBW7通过靶降解周期蛋白E、Myc、Jun等多种癌蛋白,对细胞周期进程、细胞生长、分化起重要调控作用。在多种人...FBW7(F-box and WD repeat domain-containing7)是F-box蛋白家族成员,为SCF(SKP1-CUL1-F-box)型泛素连接酶的靶蛋白识别组分。FBW7通过靶降解周期蛋白E、Myc、Jun等多种癌蛋白,对细胞周期进程、细胞生长、分化起重要调控作用。在多种人类肿瘤中已发现FBW7突变,FBW7功能缺失会引起染色体不稳定及肿瘤发生,表明FBW7是一种肿瘤抑制因子。在FBW7缺失所致的肿瘤发生过程中,周期蛋白E、Myc等靶蛋白活性升高、p53功能缺失有重要作用。展开更多
BACKGROUND: FBW7 is a tumor suppressor which regulates a network of proteins with central roles in cell division, cell growth and differentiation. This study aimed to evaluate the role of FBW7in chemosensitivity and e...BACKGROUND: FBW7 is a tumor suppressor which regulates a network of proteins with central roles in cell division, cell growth and differentiation. This study aimed to evaluate the role of FBW7in chemosensitivity and epithelial-mesenchymal transition (EMT) in different hepatocellular carcinoma (HCC) cell lines and to investigate the relevant underlying mechanisms.METHODS: Different human HCC cell lines (Hep3B, Huh-7,and SNU-449) were cultured. The cell viability was evaluated by cell counting kit-8, and FBW7 mRNA transcription and protein expression were quantitated by real-time PCR and Western blotting. Expressions of vimentin (mesenchymal biomarker)and E-cadherin (epithelial biomarker) were evaluated by Western blotting and immunocytochemistry. Cell invasion was assayed by Transwell migration, and FBW7 plasmid or siRNA was used to evaluate the effect of FBW7 overexpression or silencing on cell chemosensitivity.RESULTS: FBW7 expression affected tumor cell chemosensitivity to doxorubicin and tumor cell invasive capacity in different HCC cell lines. FBW7hi (high FBW7 expression) Hep3B and FBW7mi (median FBW7 expression) Huh-7 cells were more sensitive to doxorubicin and lower in invasive capacity than FBW7lo (low FBW7 expression) SNU-449 cells. Silencing of FBW7in Huh-7 and Hep3B cells induced the resistance to doxorubicin and enhanced cell invasion, whereas overexpression of FBW7in SNU-449 cells restored the sensitivity to doxorubicin andsignificantly reduced invasive capacity. Furthermore, doxorubicin induced EMT toward mesenchyme in HCC cells. Downregulation of FBW7 in Huh-7 and Hep3B cells or upregulation of FBW7 in SNU-449 cells altered the direction of EMT.CONCLUSIONS: The level of FBW7 expression impacted the tumor resistance to doxorubicin and the invasion capability of HCC cells. FBW7 therefore may be a potential target for the chemotherapy of HCC through the regulation of EMT.展开更多
目的:探讨FBW7(F-box/WD repeat-containing protein 7)是否参与转录抑制因子Snail的泛素化修饰,通过调节上皮间质转化(EMT)进而导致非小细胞肺癌的侵袭和转移,为治疗非小细胞肺癌(NSCLC)患者晚期转移提供新的思路。方法:首先,通过Weste...目的:探讨FBW7(F-box/WD repeat-containing protein 7)是否参与转录抑制因子Snail的泛素化修饰,通过调节上皮间质转化(EMT)进而导致非小细胞肺癌的侵袭和转移,为治疗非小细胞肺癌(NSCLC)患者晚期转移提供新的思路。方法:首先,通过Western Blot方法检测多种人肺细胞系中Snail的表达水平。上调(药物处理)及下调(设计并合成特异性sh RNA转染)H460细胞中FBW7的表达后,检测Snail的表达水平。采用平板克隆及Transwell方法检测下调FBW7的H460细胞形态改变和侵袭转移能力变化。结果:人非小细胞肺癌H460细胞中Snail表达水平较高。上调FBW7表达可使Snail表达下降,经蛋白酶抑制剂MG132处理后Snail表达升高;而下调FBW7表达后Snail表达增加。下调FBW7表达细胞后,细胞形态改变,侵袭转移能力增强。结论:FBW7参与了Snail泛素化修饰,进而经蛋白酶体途径将其降解引起EMT,导致肿瘤转移和进展的发生。展开更多
Gain-of-function (GOF), the most malicious oncogenic activity of a cancer-promoting protein, is well illustrated to three hotspot p53 mutations at R248, R175, and R273 with distinct molecular mechanisms. Yet, less is ...Gain-of-function (GOF), the most malicious oncogenic activity of a cancer-promoting protein, is well illustrated to three hotspot p53 mutations at R248, R175, and R273 with distinct molecular mechanisms. Yet, less is known about another hotspot p53 mutant, R249S (p53-R249S). p53-R249S is the sole hotspot mutation in hepatocellular carcinoma (HCC) that is highly associated with chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1). Its GOF is suggested by the facts that this mutant is associated with earlier onset of HCC and poorer prognosis of cancer patients and that its overexpression drives HCC proliferation and tumorigenesis. By contrast, simply knocking in this mutant in normal mice did not show apparent GOF activity. Hence, the GOF activity for p53-R249S and its underlying mechanisms have been elusive until recent findings offered some new insights. This review will discuss these findings as well as their clinical significance and implications for the development of a strategy to target multiple molecules as a therapy for p53-R249S-harboring HCC.展开更多
The prevalence of functionalized nanoparticles in biological and clinical fields attracts intensive toxicology investigations.Minimizing the nanoparticles’ biohazard remains a challenge due to the insufficient unders...The prevalence of functionalized nanoparticles in biological and clinical fields attracts intensive toxicology investigations.Minimizing the nanoparticles’ biohazard remains a challenge due to the insufficient understanding on the nanoparticle-induced cell death mechanism.In the presented study,we observed the lysosome and genome injuries and so caused cell cycle changes and regulations of retinal ganglion neuron cell 5(RGC-5) induced by aminated and alkylated nanoparticles.Alkylated nanoparticles induced malignant lysosome and genome damages followed by severe post-self-repair responses.RGC-5 treated with alkylated nanoparticles presented dramatic S phase prolongation resulted from cyclin E accumulation mediated by Fbw7 downregulation,which assisted DNA replication after failed self-repair of the malignantly damaged DNA caused by alkylated nanoparticles.Differently,aminated nanoparticles in RGC-5 induced moderate lysosome and genome injuries and these damages could be repaired in the p21-involved pathway,so that cells did not induce apparent cyclin E accumulation nor Fbw7 downregulation as post-self-repair response.These results helped us to understand the toxicity of analogous nanoparticles on retinal ganglions such as glaucoma treatment.This work provides new insights into nanoparticle functionalization and toxicity in relation to the research on the toxicology and pathology of nerve cells.展开更多
基金Supported by Grants from National Basic Research Program of China,973 program,No.2010CB529704 and No.2012CB910404National Natural Science Foundation of China,No.30800587,No.30971521,and No.31171338+1 种基金the Science and Technology Commission of Shanghai Municipality,No.11DZ2260300a scholar of the Shanghai Rising-Star Program from Science and Technology Commission of Shanghai Municipality,No.09QA1401900 to Wang P
文摘Krüppel-like factor(KLF) family proteins are transcription factors that regulate numerous cellular functions, such as cell proliferation, differentiation, and cell death. Posttranslational modification of KLF proteins is important for their transcriptional activities and biological functions. One KLF family member with important roles in cell proliferation and tumorigenesis is KLF5. The function of KLF5 is tightly controlled by post-translational modifications, including SUMOylation, phosphorylation, and ubiquitination. Recent studies from our lab and others' have demonstrated that the tumor suppressor FBW7 is an essential E3 ubiquitin ligase that targets KLF5 for ubiquitination and degradation. KLF5 contains functional Cdc4 phospho-degrons(CPDs), which are required for its interaction with FBW7. Mutation of CPDs in KLF5 blocks the ubiquitination and degradation of KLF5 by FBW7. The protein kinase Glycogen synthase kinase 3β is involved in the phosphorylation of KLF5 CPDs. In both cancer cell lines and mousemodels, it has been shown that FBW7 regulates the expression of KLF5 target genes through the modulation of KLF5 stability. In this review, we summarize the current progress on delineating FBW7-mediated KLF5 ubiquitination and degradation.
文摘FBW7(F-box and WD repeat domain-containing7)是F-box蛋白家族成员,为SCF(SKP1-CUL1-F-box)型泛素连接酶的靶蛋白识别组分。FBW7通过靶降解周期蛋白E、Myc、Jun等多种癌蛋白,对细胞周期进程、细胞生长、分化起重要调控作用。在多种人类肿瘤中已发现FBW7突变,FBW7功能缺失会引起染色体不稳定及肿瘤发生,表明FBW7是一种肿瘤抑制因子。在FBW7缺失所致的肿瘤发生过程中,周期蛋白E、Myc等靶蛋白活性升高、p53功能缺失有重要作用。
基金supported by grants from NationalHigh-Tech Research and Development Projects (863 Program)(2012AA021002)Organ Transplantation Key Technology Project(863 Program) (2012AA022409)Zhejiang Province NaturalScience Foundation (LQ12H03002 and LY12H03010)
文摘BACKGROUND: FBW7 is a tumor suppressor which regulates a network of proteins with central roles in cell division, cell growth and differentiation. This study aimed to evaluate the role of FBW7in chemosensitivity and epithelial-mesenchymal transition (EMT) in different hepatocellular carcinoma (HCC) cell lines and to investigate the relevant underlying mechanisms.METHODS: Different human HCC cell lines (Hep3B, Huh-7,and SNU-449) were cultured. The cell viability was evaluated by cell counting kit-8, and FBW7 mRNA transcription and protein expression were quantitated by real-time PCR and Western blotting. Expressions of vimentin (mesenchymal biomarker)and E-cadherin (epithelial biomarker) were evaluated by Western blotting and immunocytochemistry. Cell invasion was assayed by Transwell migration, and FBW7 plasmid or siRNA was used to evaluate the effect of FBW7 overexpression or silencing on cell chemosensitivity.RESULTS: FBW7 expression affected tumor cell chemosensitivity to doxorubicin and tumor cell invasive capacity in different HCC cell lines. FBW7hi (high FBW7 expression) Hep3B and FBW7mi (median FBW7 expression) Huh-7 cells were more sensitive to doxorubicin and lower in invasive capacity than FBW7lo (low FBW7 expression) SNU-449 cells. Silencing of FBW7in Huh-7 and Hep3B cells induced the resistance to doxorubicin and enhanced cell invasion, whereas overexpression of FBW7in SNU-449 cells restored the sensitivity to doxorubicin andsignificantly reduced invasive capacity. Furthermore, doxorubicin induced EMT toward mesenchyme in HCC cells. Downregulation of FBW7 in Huh-7 and Hep3B cells or upregulation of FBW7 in SNU-449 cells altered the direction of EMT.CONCLUSIONS: The level of FBW7 expression impacted the tumor resistance to doxorubicin and the invasion capability of HCC cells. FBW7 therefore may be a potential target for the chemotherapy of HCC through the regulation of EMT.
文摘Gain-of-function (GOF), the most malicious oncogenic activity of a cancer-promoting protein, is well illustrated to three hotspot p53 mutations at R248, R175, and R273 with distinct molecular mechanisms. Yet, less is known about another hotspot p53 mutant, R249S (p53-R249S). p53-R249S is the sole hotspot mutation in hepatocellular carcinoma (HCC) that is highly associated with chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1). Its GOF is suggested by the facts that this mutant is associated with earlier onset of HCC and poorer prognosis of cancer patients and that its overexpression drives HCC proliferation and tumorigenesis. By contrast, simply knocking in this mutant in normal mice did not show apparent GOF activity. Hence, the GOF activity for p53-R249S and its underlying mechanisms have been elusive until recent findings offered some new insights. This review will discuss these findings as well as their clinical significance and implications for the development of a strategy to target multiple molecules as a therapy for p53-R249S-harboring HCC.
基金supported by the National Natural Science Foundation of China (Nos.11204033,51773093)the Natural Science Foundation of Jiangsu Province (No.BK20141397)+3 种基金the Research Fund for the Doctoral Program of Higher Education of China (No.20120092120042)the CMA L’Oreal China Skin Grant 2015 (No.S2015121421)the Open Research Fund of State Key Laboratory of Natural Medicines,China Pharmaceutical University (No.SKLNMKF201803)Southeast University and Nanjing MedicalUniversity Cooperation Project (No.2242018K3DN14)
文摘The prevalence of functionalized nanoparticles in biological and clinical fields attracts intensive toxicology investigations.Minimizing the nanoparticles’ biohazard remains a challenge due to the insufficient understanding on the nanoparticle-induced cell death mechanism.In the presented study,we observed the lysosome and genome injuries and so caused cell cycle changes and regulations of retinal ganglion neuron cell 5(RGC-5) induced by aminated and alkylated nanoparticles.Alkylated nanoparticles induced malignant lysosome and genome damages followed by severe post-self-repair responses.RGC-5 treated with alkylated nanoparticles presented dramatic S phase prolongation resulted from cyclin E accumulation mediated by Fbw7 downregulation,which assisted DNA replication after failed self-repair of the malignantly damaged DNA caused by alkylated nanoparticles.Differently,aminated nanoparticles in RGC-5 induced moderate lysosome and genome injuries and these damages could be repaired in the p21-involved pathway,so that cells did not induce apparent cyclin E accumulation nor Fbw7 downregulation as post-self-repair response.These results helped us to understand the toxicity of analogous nanoparticles on retinal ganglions such as glaucoma treatment.This work provides new insights into nanoparticle functionalization and toxicity in relation to the research on the toxicology and pathology of nerve cells.
