BACKGROUND The ubiquitin-proteasome pathway(UPP)has been proven to play important roles in cancer.AIM To investigate the prognostic significance of genes involved in the UPP and develop a predictive model for liver ca...BACKGROUND The ubiquitin-proteasome pathway(UPP)has been proven to play important roles in cancer.AIM To investigate the prognostic significance of genes involved in the UPP and develop a predictive model for liver cancer based on the expression of these genes.METHODS In this study,UPP-related E1,E2,E3,deubiquitylating enzyme,and proteasome gene sets were obtained from the Kyoto Encyclopedia of Genes and Genomes(KEGG)database,aiming to screen the prognostic genes using univariate and multivariate regression analysis and develop a prognosis predictive model based RESULTS Five genes(including autophagy related 10,proteasome 20S subunit alpha 8,proteasome 20S subunit beta 2,ubiquitin specific peptidase 17 like family member 2,and ubiquitin specific peptidase 8)were proven significantly correlated with prognosis and used to develop a prognosis predictive model for liver cancer.Among training,validation,and Gene Expression Omnibus sets,the overall survival differed significantly between the high-risk and low-risk groups.The expression of the five genes was significantly associated with immunocyte infiltration,tumor stage,and postoperative recurrence.A total of 111 differentially expressed genes(DEGs)were identified between the high-risk and low-risk groups and they were enriched in 20 and 5 gene ontology and KEGG pathways.Cell division cycle 20,Kelch repeat and BTB domain containing 11,and DDB1 and CUL4 associated factor 4 like 2 were the DEGs in the E3 gene set that correlated with survival.CONCLUSION We have constructed a prognosis predictive model in patients with liver cancer,which contains five genes that associate with immunocyte infiltration,tumor stage,and postoperative recurrence.展开更多
Endocrine therapy using estrogen receptor-α(ER-α) antagonists for attenuating horm2one-driven cell proliferation is a major treatment modality for breast cancers.To exploit any DNA repair deficiencies associated wit...Endocrine therapy using estrogen receptor-α(ER-α) antagonists for attenuating horm2one-driven cell proliferation is a major treatment modality for breast cancers.To exploit any DNA repair deficiencies associated with endocrine therapy,we investigated the functional and physical interactions of ER-α with O^6-methylguanine DNA methyltransferase(MGMT),a unique DNA repair protein that confers tumor resistance to various anticancer alkylating agents.The ER-α-positive breast cancer cell lines(MCF-7,T47D) and ER- negative cell lines(MDAMB-468,MDAMB-231),and established inhibitors of ER-α and MGMT,namely,ICI-182,780(Faslodex) and O^6-benzylguanine,respectively,were used to study MGMT- ER interactions.The MGMT gene promoter was found to harbor one full and two half estrogen-responsive elements(EREs) and two antioxidant-responsive elements(AREs).MGMT expression was upregulated by estrogen,downregulated by tamoxifen in Western blot and promoter-linked reporter assays.Similarly,both transient and stable transfections of Nrf-2(nuclear factor-erythroid 2-related factor-2)increased the levels of MGMT protein and activity 3 to 4-fold reflecting novel regulatory nodes for this drugresistance determinant.Of the different ER-α antagonists tested,the pure anti-estrogen fulvestrant was most potent in inhibiting the MGMT activity in a dose,time and ER-α dependent manner,similar to O^6-benzylguanine.Interestingly,fulvestrant exposure led to a degradation of both ER-α and MGMT proteins and O^6-benzylguanine also induced a specific loss of ER-α and MGMT proteins in MCF-7 and T47 D breast cancer cells with similar kinetics.Immunoprecipitation revealed a specific association of ER-α and MGMT proteins in breast cancer cells.Furthermore,silencing of MGMT gene expression triggered a decrease in the levels of both MGMT and ER-α proteins.The involvement of proteasome in the drug-induced degradation of both proteins was also demonstrated.Fulvestrant enhanced the cytotoxicity of MGMT-targeted alkylating agents,namely,temozolomide and BCNU by 3 to 4-fold in ER-α positive cells,but not in ER-negative cells.We conclude that MGMT and ER-α proteins exist as a complex and are co-targeted for ubiquitin-conjugation and subsequent proteasomal degradation.The findings offer a clear rationale for combining alkylating agents with endocrine therapy.展开更多
Objective To investigate the dynamic expression of the 20S proteasome in peripheral blood mononuclear cells(PBMCs)of type 2 diabetic patients without vascular complications.Methods PBMCs were prepared from 30 type 2 d...Objective To investigate the dynamic expression of the 20S proteasome in peripheral blood mononuclear cells(PBMCs)of type 2 diabetic patients without vascular complications.Methods PBMCs were prepared from 30 type 2 diabetic patients and 30 nondiabetic controls.The general indexes including weight,height and blood pressure were recorded.Fasting plasma glucose,fasting plasma insulin and glycosylated hemoglobin were measured.The protein level of the 20S proteasome was measured by Western blotting.The mRNA expression levels of the 20S proteasome β1,β2 and β5 subunits were detected by real-time PCR.Results Compared with that in the nondiabetic controls,the protein level of the 20S proteasome was significantly increased in the diabetic patients and was positively associated with glycosylated hemoglobin.Conclusion Type 2 diabetic patients without vascular complications have an increased 20S proteasome expression,the significance of which needs to be explored by further study.展开更多
In mammals,mitofusin 2(MFN2)is involved in mitochondrial fusion,and suppresses the virus-induced RIG-I-like receptor(RLR)signaling pathway.However,little is known about the function of MFN2 in non-mammalian species.In...In mammals,mitofusin 2(MFN2)is involved in mitochondrial fusion,and suppresses the virus-induced RIG-I-like receptor(RLR)signaling pathway.However,little is known about the function of MFN2 in non-mammalian species.In the present study,we cloned an MFN2 ortholog(LcMFN2)in large yellow croaker(Larimichthys crocea).Phylogenetic analysis showed that MFN2 emerged after the divergence of amphioxus and vertebrates.The protein sequences of MFN2 were well conserved from fsh to mammals.LcMFN2 was expressed in all the tissues/organs examined at diferent levels,and its expression was upregulated in response to poly(I:C)stimulation.Overexpression of LcMFN2 inhibited MAVS-induced type I interferon(IFN)promoter activation and antiviral gene expression.In contrast,knockdown of endogenous LcMFN2 enhanced poly(I:C)induced production of type I IFNs.Additionally,LcMFN2 enhanced K48-linked polyubiquitination of MAVS,promoting its degradation.Also,overexpression of LcMFN2 impaired the cellular antiviral response,as evidenced by the increased expression of viral genes and more severe cytopathic efects(CPE)in cells infected with spring viremia of carp virus(SVCV).These results indicated that LcMFN2 inhibited type I IFN response by degrading MAVS,suggesting its negative regulatory role in cellular antiviral response.Therefore,our study sheds a new light on the regulatory mechanisms of the cellular antiviral response in teleosts.展开更多
基金the Tianjin Municipal Natural Science Foundation,No.21JCYBJC01110。
文摘BACKGROUND The ubiquitin-proteasome pathway(UPP)has been proven to play important roles in cancer.AIM To investigate the prognostic significance of genes involved in the UPP and develop a predictive model for liver cancer based on the expression of these genes.METHODS In this study,UPP-related E1,E2,E3,deubiquitylating enzyme,and proteasome gene sets were obtained from the Kyoto Encyclopedia of Genes and Genomes(KEGG)database,aiming to screen the prognostic genes using univariate and multivariate regression analysis and develop a prognosis predictive model based RESULTS Five genes(including autophagy related 10,proteasome 20S subunit alpha 8,proteasome 20S subunit beta 2,ubiquitin specific peptidase 17 like family member 2,and ubiquitin specific peptidase 8)were proven significantly correlated with prognosis and used to develop a prognosis predictive model for liver cancer.Among training,validation,and Gene Expression Omnibus sets,the overall survival differed significantly between the high-risk and low-risk groups.The expression of the five genes was significantly associated with immunocyte infiltration,tumor stage,and postoperative recurrence.A total of 111 differentially expressed genes(DEGs)were identified between the high-risk and low-risk groups and they were enriched in 20 and 5 gene ontology and KEGG pathways.Cell division cycle 20,Kelch repeat and BTB domain containing 11,and DDB1 and CUL4 associated factor 4 like 2 were the DEGs in the E3 gene set that correlated with survival.CONCLUSION We have constructed a prognosis predictive model in patients with liver cancer,which contains five genes that associate with immunocyte infiltration,tumor stage,and postoperative recurrence.
基金supported by grants from the Cancer Prevention Research Institute of Texas(RP130266)the Carson-Leslie Foundation and the Association for Research of Childhood Cancer
文摘Endocrine therapy using estrogen receptor-α(ER-α) antagonists for attenuating horm2one-driven cell proliferation is a major treatment modality for breast cancers.To exploit any DNA repair deficiencies associated with endocrine therapy,we investigated the functional and physical interactions of ER-α with O^6-methylguanine DNA methyltransferase(MGMT),a unique DNA repair protein that confers tumor resistance to various anticancer alkylating agents.The ER-α-positive breast cancer cell lines(MCF-7,T47D) and ER- negative cell lines(MDAMB-468,MDAMB-231),and established inhibitors of ER-α and MGMT,namely,ICI-182,780(Faslodex) and O^6-benzylguanine,respectively,were used to study MGMT- ER interactions.The MGMT gene promoter was found to harbor one full and two half estrogen-responsive elements(EREs) and two antioxidant-responsive elements(AREs).MGMT expression was upregulated by estrogen,downregulated by tamoxifen in Western blot and promoter-linked reporter assays.Similarly,both transient and stable transfections of Nrf-2(nuclear factor-erythroid 2-related factor-2)increased the levels of MGMT protein and activity 3 to 4-fold reflecting novel regulatory nodes for this drugresistance determinant.Of the different ER-α antagonists tested,the pure anti-estrogen fulvestrant was most potent in inhibiting the MGMT activity in a dose,time and ER-α dependent manner,similar to O^6-benzylguanine.Interestingly,fulvestrant exposure led to a degradation of both ER-α and MGMT proteins and O^6-benzylguanine also induced a specific loss of ER-α and MGMT proteins in MCF-7 and T47 D breast cancer cells with similar kinetics.Immunoprecipitation revealed a specific association of ER-α and MGMT proteins in breast cancer cells.Furthermore,silencing of MGMT gene expression triggered a decrease in the levels of both MGMT and ER-α proteins.The involvement of proteasome in the drug-induced degradation of both proteins was also demonstrated.Fulvestrant enhanced the cytotoxicity of MGMT-targeted alkylating agents,namely,temozolomide and BCNU by 3 to 4-fold in ER-α positive cells,but not in ER-negative cells.We conclude that MGMT and ER-α proteins exist as a complex and are co-targeted for ubiquitin-conjugation and subsequent proteasomal degradation.The findings offer a clear rationale for combining alkylating agents with endocrine therapy.
文摘Objective To investigate the dynamic expression of the 20S proteasome in peripheral blood mononuclear cells(PBMCs)of type 2 diabetic patients without vascular complications.Methods PBMCs were prepared from 30 type 2 diabetic patients and 30 nondiabetic controls.The general indexes including weight,height and blood pressure were recorded.Fasting plasma glucose,fasting plasma insulin and glycosylated hemoglobin were measured.The protein level of the 20S proteasome was measured by Western blotting.The mRNA expression levels of the 20S proteasome β1,β2 and β5 subunits were detected by real-time PCR.Results Compared with that in the nondiabetic controls,the protein level of the 20S proteasome was significantly increased in the diabetic patients and was positively associated with glycosylated hemoglobin.Conclusion Type 2 diabetic patients without vascular complications have an increased 20S proteasome expression,the significance of which needs to be explored by further study.
基金This work was supported by National Key Research and Development Program of China under Grant No.2022YFD2401001National Natural Science Foundation of China under Grant No.U1905204+2 种基金China Agriculture Research System of MOF and MARA under Grant No.CARS-47Fujian Science and Technology Department under Grant No.2021N5008Institute of Oceanology of Fuzhou(2021F02).
文摘In mammals,mitofusin 2(MFN2)is involved in mitochondrial fusion,and suppresses the virus-induced RIG-I-like receptor(RLR)signaling pathway.However,little is known about the function of MFN2 in non-mammalian species.In the present study,we cloned an MFN2 ortholog(LcMFN2)in large yellow croaker(Larimichthys crocea).Phylogenetic analysis showed that MFN2 emerged after the divergence of amphioxus and vertebrates.The protein sequences of MFN2 were well conserved from fsh to mammals.LcMFN2 was expressed in all the tissues/organs examined at diferent levels,and its expression was upregulated in response to poly(I:C)stimulation.Overexpression of LcMFN2 inhibited MAVS-induced type I interferon(IFN)promoter activation and antiviral gene expression.In contrast,knockdown of endogenous LcMFN2 enhanced poly(I:C)induced production of type I IFNs.Additionally,LcMFN2 enhanced K48-linked polyubiquitination of MAVS,promoting its degradation.Also,overexpression of LcMFN2 impaired the cellular antiviral response,as evidenced by the increased expression of viral genes and more severe cytopathic efects(CPE)in cells infected with spring viremia of carp virus(SVCV).These results indicated that LcMFN2 inhibited type I IFN response by degrading MAVS,suggesting its negative regulatory role in cellular antiviral response.Therefore,our study sheds a new light on the regulatory mechanisms of the cellular antiviral response in teleosts.
