Objectives:Although claudin-1(CLDN1)interacts with Cluster of Differentiation 81(CD81)in various cell types,the specific mechanism underlying this interaction and its functional implications in colorectal cancer(CRC)c...Objectives:Although claudin-1(CLDN1)interacts with Cluster of Differentiation 81(CD81)in various cell types,the specific mechanism underlying this interaction and its functional implications in colorectal cancer(CRC)cells remain poorly understood.This study outlines the regulatory role of CLDN1 in CRC cell tumorigenicity through its interaction with CD81,elucidating the underlying signaling cascade.Methods:Changes in the expression of CLDN1 and CD81,as well as their correlation with the survival of CRC patients,were analyzed using samples from The Cancer Genome Atlas database,the Kaplan–Meier plotter database,and tissue microarrays.CLDN1 and CD81 were silenced in CRC cell lines to examine their effects on cell viability,migration,and invasion.The interaction between CLDN1 and CD81,as well as the regulation of CD81,was examined via coimmunoprecipitation and ubiquitination analysis.CLDN1-overexpressing SW620 cells and a xenograft tumor model were cotreated with the anti-CD81 monoclonal antibody(mAb)5A6 to investigate the role of the CLDN1/CD81 axis in CRC tumor growth.Results:CLDN1 expression was enhanced in CRC tissue and was correlated with poor survival in patients.Analysis revealed a significant upregulation of CLDN1 in all examined CRC cell lines relative to normal intestinal epithelial controls.Silencing of CLDN1 and CD81 reduced the CRC cell viability,invasion and migration.CLDN1 interacted with CD81 and promoted CD81 expression by suppressing CD81 ubiquitination.The anti-CD81 mAb 5A6 reversed the functions of CLDN1 overexpression in CRC malignant phenotypes and tumor xenograft growth.Conclusion:This study establishes CLDN1 as a promising therapeutic target in CRC and reveals that disrupting the CLDN1/CD81 axis might represent a novel treatment strategy.展开更多
AIM: To further analyze the interaction of tupaia CD81 with hepatitis C virus (HCV) envelope protein E2. METHODS: A tupaia CD81 large extracellular loop (CD81 LEL), which binds to HCV E2 protein, was cloned and expres...AIM: To further analyze the interaction of tupaia CD81 with hepatitis C virus (HCV) envelope protein E2. METHODS: A tupaia CD81 large extracellular loop (CD81 LEL), which binds to HCV E2 protein, was cloned and expressed as a GST-fusion protein, and interaction of HCV E2 protein with a tupaia CD81 LEL was evaluated by enzyme-linked immunosorbent assay (EIA). RESULTS: Although tupaia and human CD81 LEL differed in 6 amino acid changes, tupaia CD81 LEL was strongly recognized by anti-CD81 antibodies against human CD81 LEL conformation-dependent epitopes. Investigating LEL CD81-E2 interactions by EIA, we demonstrated that binding of tupaia CD81 LEL GST fusion protein to recombinant HCV E2 protein was markedly reduced compared to binding of human CD81 LEL GST fusion protein to recombinant HCV E2 protein. CONCLUSION: These data suggest that the structural differences in-between the tupaia and human CD81 may alter the interaction of the large extracellular loop with HCV envelope glycoprotein E2. These findings may be important for the understanding of the mechanisms of binding and entry of HCV to PTHs.展开更多
基金funded by the Shanghai Jinshan District Municipal Commission of Health(No.JSZK2023A02)the Fudan University Affiliated Jinshan Hospital Youth Research Start-up Fund(No.JYQN-LC-202407).
摘要Objectives:Although claudin-1(CLDN1)interacts with Cluster of Differentiation 81(CD81)in various cell types,the specific mechanism underlying this interaction and its functional implications in colorectal cancer(CRC)cells remain poorly understood.This study outlines the regulatory role of CLDN1 in CRC cell tumorigenicity through its interaction with CD81,elucidating the underlying signaling cascade.Methods:Changes in the expression of CLDN1 and CD81,as well as their correlation with the survival of CRC patients,were analyzed using samples from The Cancer Genome Atlas database,the Kaplan–Meier plotter database,and tissue microarrays.CLDN1 and CD81 were silenced in CRC cell lines to examine their effects on cell viability,migration,and invasion.The interaction between CLDN1 and CD81,as well as the regulation of CD81,was examined via coimmunoprecipitation and ubiquitination analysis.CLDN1-overexpressing SW620 cells and a xenograft tumor model were cotreated with the anti-CD81 monoclonal antibody(mAb)5A6 to investigate the role of the CLDN1/CD81 axis in CRC tumor growth.Results:CLDN1 expression was enhanced in CRC tissue and was correlated with poor survival in patients.Analysis revealed a significant upregulation of CLDN1 in all examined CRC cell lines relative to normal intestinal epithelial controls.Silencing of CLDN1 and CD81 reduced the CRC cell viability,invasion and migration.CLDN1 interacted with CD81 and promoted CD81 expression by suppressing CD81 ubiquitination.The anti-CD81 mAb 5A6 reversed the functions of CLDN1 overexpression in CRC malignant phenotypes and tumor xenograft growth.Conclusion:This study establishes CLDN1 as a promising therapeutic target in CRC and reveals that disrupting the CLDN1/CD81 axis might represent a novel treatment strategy.
基金Supported by Grants from Health Department of Hubei Province (JX2B09)NSFC (30771911)National 973 Key Program (2009CB522502), and Tongji Hospital
摘要AIM: To further analyze the interaction of tupaia CD81 with hepatitis C virus (HCV) envelope protein E2. METHODS: A tupaia CD81 large extracellular loop (CD81 LEL), which binds to HCV E2 protein, was cloned and expressed as a GST-fusion protein, and interaction of HCV E2 protein with a tupaia CD81 LEL was evaluated by enzyme-linked immunosorbent assay (EIA). RESULTS: Although tupaia and human CD81 LEL differed in 6 amino acid changes, tupaia CD81 LEL was strongly recognized by anti-CD81 antibodies against human CD81 LEL conformation-dependent epitopes. Investigating LEL CD81-E2 interactions by EIA, we demonstrated that binding of tupaia CD81 LEL GST fusion protein to recombinant HCV E2 protein was markedly reduced compared to binding of human CD81 LEL GST fusion protein to recombinant HCV E2 protein. CONCLUSION: These data suggest that the structural differences in-between the tupaia and human CD81 may alter the interaction of the large extracellular loop with HCV envelope glycoprotein E2. These findings may be important for the understanding of the mechanisms of binding and entry of HCV to PTHs.