Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o ...Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o rganisms,plants and animals through direct or indirect exposure.However,the current understanding of the toxicity of copper is rather limited.Copper overload can perturb intracellular homeostasis and induce oxidative stress and e ven cell death.Recently,cuproptosis has been identified as a copper-dependent form of cell death induced by o xidative stress in mitochondria.We uncover here that zinc transporter 1(ZNT1)is an important regulator involved in cuproptosis.Firstly,we established the copper overload-induced cell death model with the overexpression of copper importer SLC31A1 in HeLa cells.Using this model,we conducted unbiased genome-wide CRISPR-Cas9 screens in cells treated with copper.Our results revealed a significant enrichment of ZNT1 gene in both library A and library B plasmids.Knocking out of ZNT1 in HeLa cells notably prevented cuproptosis.Subsequent knockout of metal transcription factor 1(MTF1)in ZNT1-deficient cells nearly abolished their ability to resist copper-induced cell death.However,overexpression of metallothionein 1X(MT1X)in the double-knockout cells could p artially restored the resistance to cuproptosis by loss of MTF1.Mechanistically,knockout of ZNT1 could promote MT1X expression by activating MTF1.As a consequence,the interaction between MT1X and copper was e nhanced,reducing the flow of copper into mitochondria and eliminating mitochondria damage.Taken together,this study reveals the important role of ZNT1 in cuproptosis and shows MTF1-MT1X axis mediated resistance to c uproptosis.Moreover,our study will help to understand the regulatory mechanism of cellular and systemic copper homeostasis under copper overload,and present insights into novel treatments for damages caused by both genetic copper overload diseases and environmental copper contamination.展开更多
AIM:To investigate the potential of promoter methylation of two tumor suppressor genes(TSGs)as biomarkers for hepatocellular carcinoma(HCC).METHODS:A total of 189 subjects were included in this retrospective cohort,wh...AIM:To investigate the potential of promoter methylation of two tumor suppressor genes(TSGs)as biomarkers for hepatocellular carcinoma(HCC).METHODS:A total of 189 subjects were included in this retrospective cohort,which contained 121 HCC patients without any history of curative treatment,37 patients with chronic hepatitis B(CHB),and 31 normal controls(NCs).DNA samples were extracted from 400μL of serum of each subject and then modified using bisulfite treatment.Methylation of the promoters of the TSGs(metallothionein1M,MT1M;and metallothionein 1G,MT1G)was determined using methylation-specific polymerase chain reaction.The diagnostic value of combined MT1M and MT1G promoter methylation was evaluated using the area under the receiver operating characteristic curves.RESULTS:Our results indicated that the methylation status of serum MT1M(48.8%,59/121)and MT1G(70.2%,85/121)promoters in the HCC group was significantly higher than that in the CHB group(MT1M 5.4%,2/37,P<0.001;MT1G 16.2%,6/37,P<0.001)and NC group(MT1M 6.5%,2/31,P<0.001;MT1G 12.9%,4/27,P<0.001).Aberrant serum MT1M promoter methylation gave higher specificity to discriminate HCC from CHB(94.6%)and NCs(93.5%),whereas combined methylation of serum MT1M and MT1G promoters showed higher diagnostic sensitivity(90.9%),suggesting that they are potential markers for noninvasive detection of HCC.Furthermore,MT1M promoter methylation was positively correlated with tumor size(rs=0.321,P<0.001),and HCC patients with both MT1M and MT1G promoter methylation tended to show a higher incidence of vascular invasion or metastasis(P=0.018).CONCLUSION:MT1M and MT1G promoter methylation may be used as serum biomarkers for noninvasive detection of HCC.展开更多
文摘Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o rganisms,plants and animals through direct or indirect exposure.However,the current understanding of the toxicity of copper is rather limited.Copper overload can perturb intracellular homeostasis and induce oxidative stress and e ven cell death.Recently,cuproptosis has been identified as a copper-dependent form of cell death induced by o xidative stress in mitochondria.We uncover here that zinc transporter 1(ZNT1)is an important regulator involved in cuproptosis.Firstly,we established the copper overload-induced cell death model with the overexpression of copper importer SLC31A1 in HeLa cells.Using this model,we conducted unbiased genome-wide CRISPR-Cas9 screens in cells treated with copper.Our results revealed a significant enrichment of ZNT1 gene in both library A and library B plasmids.Knocking out of ZNT1 in HeLa cells notably prevented cuproptosis.Subsequent knockout of metal transcription factor 1(MTF1)in ZNT1-deficient cells nearly abolished their ability to resist copper-induced cell death.However,overexpression of metallothionein 1X(MT1X)in the double-knockout cells could p artially restored the resistance to cuproptosis by loss of MTF1.Mechanistically,knockout of ZNT1 could promote MT1X expression by activating MTF1.As a consequence,the interaction between MT1X and copper was e nhanced,reducing the flow of copper into mitochondria and eliminating mitochondria damage.Taken together,this study reveals the important role of ZNT1 in cuproptosis and shows MTF1-MT1X axis mediated resistance to c uproptosis.Moreover,our study will help to understand the regulatory mechanism of cellular and systemic copper homeostasis under copper overload,and present insights into novel treatments for damages caused by both genetic copper overload diseases and environmental copper contamination.
基金Supported by National Natural Science Foundation of China,No.81171579,No.81201287 and No.81371832
文摘AIM:To investigate the potential of promoter methylation of two tumor suppressor genes(TSGs)as biomarkers for hepatocellular carcinoma(HCC).METHODS:A total of 189 subjects were included in this retrospective cohort,which contained 121 HCC patients without any history of curative treatment,37 patients with chronic hepatitis B(CHB),and 31 normal controls(NCs).DNA samples were extracted from 400μL of serum of each subject and then modified using bisulfite treatment.Methylation of the promoters of the TSGs(metallothionein1M,MT1M;and metallothionein 1G,MT1G)was determined using methylation-specific polymerase chain reaction.The diagnostic value of combined MT1M and MT1G promoter methylation was evaluated using the area under the receiver operating characteristic curves.RESULTS:Our results indicated that the methylation status of serum MT1M(48.8%,59/121)and MT1G(70.2%,85/121)promoters in the HCC group was significantly higher than that in the CHB group(MT1M 5.4%,2/37,P<0.001;MT1G 16.2%,6/37,P<0.001)and NC group(MT1M 6.5%,2/31,P<0.001;MT1G 12.9%,4/27,P<0.001).Aberrant serum MT1M promoter methylation gave higher specificity to discriminate HCC from CHB(94.6%)and NCs(93.5%),whereas combined methylation of serum MT1M and MT1G promoters showed higher diagnostic sensitivity(90.9%),suggesting that they are potential markers for noninvasive detection of HCC.Furthermore,MT1M promoter methylation was positively correlated with tumor size(rs=0.321,P<0.001),and HCC patients with both MT1M and MT1G promoter methylation tended to show a higher incidence of vascular invasion or metastasis(P=0.018).CONCLUSION:MT1M and MT1G promoter methylation may be used as serum biomarkers for noninvasive detection of HCC.
