Background and objective Maintenance of genomic integrity is essential to ensure normal organismal development and to prevent diseases such as cancer.PR-Set7(also known as Set8)is a cell cycle regulated enzyme that ca...Background and objective Maintenance of genomic integrity is essential to ensure normal organismal development and to prevent diseases such as cancer.PR-Set7(also known as Set8)is a cell cycle regulated enzyme that catalyses monomethylation of histone 4 at Lys20(H4K20me1)to promote chromosome condensation and prevent DNA damage.Recent studies show that CRL4CDT2-mediated ubiquitylation of PR-Set7 leads to its degradation during S phase and after DNA damage.This might occur to ensure appropriate changes in chromosome structure during the cell cycle or to preserve genome integrity after DNA damage.Methods We developed a new model of lung tumor development in mice harboring a conditionally expressed allele of Cul4A.We have therefore used a mouse model to demonstrate for the first time that Cul4A is oncogenic in vivo.With this model,staining of PR-Set7 in the preneoplastic and tumor lesions in Adeno Cre-induced mouse lungs was performed.Meanwhile we identified higher protein level changes ofγ-tubulin and pericentrin by IHC.Results The level of PR-Set7 down-regulated in the preneoplastic and adenocarcinomous lesions following over-expression of Cul4A.We also identified higher levels of the proteins pericentrin andγ-tubulin in Cul4A mouse lungs induced by Adeno Cre.Conclusion PR-Set7 is a direct target of Cul4A for degradation and involved in the formation of lung tumors in the conditional Cul4A transgenic mouse model.展开更多
Objective:The E3 ligase,CRL4,plays diverse roles in different cellular processes,such as DNA damage,transcriptional regulation,cell cycle progression,and cell apoptosis.Our previous study showed that CUL4A and CUL4B h...Objective:The E3 ligase,CRL4,plays diverse roles in different cellular processes,such as DNA damage,transcriptional regulation,cell cycle progression,and cell apoptosis.Our previous study showed that CUL4A and CUL4B had a strong association with tobacco smoking risk in lung squamous cell carcinoma(SCC)and small cell lung carcinoma(SCLC).This study aimed to define the potential mechanism underlying the roles of CUL4A and CUL4B in the development of SCC and SCLC.Methods:We determined the role of CUL4A and CUL4B in the cell cycle and apoptosis of SCC and SCLC,and identified the key apoptosis-related gene involved in the oncogenic activity of CUL4B by Western blot,immunohistochemical staining,flow cytometry,and enzyme inhibition experiments.Results:We found that depletion of CUL4A and CUL4B reduced the proliferation of SCC and SCLC cells.cUL4Aknockdown but not CUL4Bknockdown arrested cells in Gl phase while upregulating P21 and cU L4Bknockdown promoted cell apoptosis through upregulation o f FOXO3A.Accordingly,CUL4B decreased FO X03A expression by activating the ERK signaling pathway and mediating FOXO3A degradation via the ubiquitin-proteasome pathway.Conclusions:These results identified the function of E3 ligase CRL4 in regulating SCC and SCLC cell proliferation,which provides a potential strategy for cancer therapy by targeting FOXO3A and the E3 ligase,CRL4.展开更多
基金support from the Kazan, Mc Clain, Abrams, Fernandez, Lyons, Greenwood, Harley & Oberman Foundation, Incthe Estate of Robert Griffiths+3 种基金the Jeffrey and Karen Peterson Family FoundationPaul and Michelle Zygielbaumthe Estate of Norman Mancinithe Barbara Isackson Lung Cancer Research Fund
文摘Background and objective Maintenance of genomic integrity is essential to ensure normal organismal development and to prevent diseases such as cancer.PR-Set7(also known as Set8)is a cell cycle regulated enzyme that catalyses monomethylation of histone 4 at Lys20(H4K20me1)to promote chromosome condensation and prevent DNA damage.Recent studies show that CRL4CDT2-mediated ubiquitylation of PR-Set7 leads to its degradation during S phase and after DNA damage.This might occur to ensure appropriate changes in chromosome structure during the cell cycle or to preserve genome integrity after DNA damage.Methods We developed a new model of lung tumor development in mice harboring a conditionally expressed allele of Cul4A.We have therefore used a mouse model to demonstrate for the first time that Cul4A is oncogenic in vivo.With this model,staining of PR-Set7 in the preneoplastic and tumor lesions in Adeno Cre-induced mouse lungs was performed.Meanwhile we identified higher protein level changes ofγ-tubulin and pericentrin by IHC.Results The level of PR-Set7 down-regulated in the preneoplastic and adenocarcinomous lesions following over-expression of Cul4A.We also identified higher levels of the proteins pericentrin andγ-tubulin in Cul4A mouse lungs induced by Adeno Cre.Conclusion PR-Set7 is a direct target of Cul4A for degradation and involved in the formation of lung tumors in the conditional Cul4A transgenic mouse model.
基金The National Natural Science Foundation of China(Grant No.81772620 and 31471341)the Key Science and Technology Project of Tianjin Chronic Disease Prevention and Control(Grant No.17XXMFSY00130)the National Science and Technology Major Project(Grant No.2018ZX09201-015).
文摘Objective:The E3 ligase,CRL4,plays diverse roles in different cellular processes,such as DNA damage,transcriptional regulation,cell cycle progression,and cell apoptosis.Our previous study showed that CUL4A and CUL4B had a strong association with tobacco smoking risk in lung squamous cell carcinoma(SCC)and small cell lung carcinoma(SCLC).This study aimed to define the potential mechanism underlying the roles of CUL4A and CUL4B in the development of SCC and SCLC.Methods:We determined the role of CUL4A and CUL4B in the cell cycle and apoptosis of SCC and SCLC,and identified the key apoptosis-related gene involved in the oncogenic activity of CUL4B by Western blot,immunohistochemical staining,flow cytometry,and enzyme inhibition experiments.Results:We found that depletion of CUL4A and CUL4B reduced the proliferation of SCC and SCLC cells.cUL4Aknockdown but not CUL4Bknockdown arrested cells in Gl phase while upregulating P21 and cU L4Bknockdown promoted cell apoptosis through upregulation o f FOXO3A.Accordingly,CUL4B decreased FO X03A expression by activating the ERK signaling pathway and mediating FOXO3A degradation via the ubiquitin-proteasome pathway.Conclusions:These results identified the function of E3 ligase CRL4 in regulating SCC and SCLC cell proliferation,which provides a potential strategy for cancer therapy by targeting FOXO3A and the E3 ligase,CRL4.
