BACKGROUND Gastric cancer(GC)is one of the leading causes of cancer-related death worldwide.Although targeted therapies such as antibodies against human epidermal growth factor receptor 2 or vascular endothelial growt...BACKGROUND Gastric cancer(GC)is one of the leading causes of cancer-related death worldwide.Although targeted therapies such as antibodies against human epidermal growth factor receptor 2 or vascular endothelial growth factor receptor 2 have been widely used in the treatment of metastatic cancer,the overall outcomes are poor.Therefore,elucidation of the mechanism underlying cancer progression is important to improve prognosis.Overexpression of the Rab5a gene has been confirmed to correlate with tumorigenesis of many cancers,but the mechanism underling,especially of GC,is still unclear.AIM To investigate the effects of Rab5a overexpression on the tumorigenesis of GC.METHODS First,the expression levels of Rab5a and Rab4a in primary tumorous tissues of GC patients diagnosed between 2015 and 2018 were analyzed.Then we constructed HGC-27 cell lines overexpressing green fluorescent protein-Rab5a or red fluorescent protein-Rab4a and investigated the interaction between Rab5a or Rab4a using Western blotting,co-immunoprecipitation,confocal microscopy,and colocalization analysis.Finally,epidermal growth factor-stimulated proliferation of these cell lines was analyzed using cell counting kit-8 cell viability assay.RESULTS Compared with normal gastric tissues,the expression levels of Rab5a and Rab4a increased progressively both in paracancerous tissues and in advanced cancerous tissues.Epidermal growth factor could promote the proliferation of HGC-27 cells,especially Rab5a-overexpressing HGC-27 cells.Notably,Rab5a and Rab4a cooverexpression promoted the proliferation of HGC-27 cells to the greatest extent.Further analysis identified a direct interaction between Rab5a and Rab4a in HGC-27 cells.CONCLUSION Co-overexpression of Rab5a and Rab4a in GC may promote the endosomal recycling of epidermal growth factor receptor,which in turn contributes to poor prognosis and tumor progression in GC patients.Inhibition of Rab5a or Rab4a expression might be a promising therapy for refractory GC.展开更多
Rab proteins are involved in all facets of the vesicular transport process and play significant roles in different steps of the viral life cycle.Rab4b is a pivotal player in the endocytic recycling of proteins,whereas...Rab proteins are involved in all facets of the vesicular transport process and play significant roles in different steps of the viral life cycle.Rab4b is a pivotal player in the endocytic recycling of proteins,whereas its roles in viral replication are still largely unknown.Our earlier work identified Rab4b as a host factor required to replicate the influenza A virus(IAV).Here,we further validated the impact of Rab4b on viral replication by silencing or overexpressing Rab4b.The results showed that silencing Rab4b significantly decreased IAV and influenza B virus(IBV)production.Overexpression of Rab4b enhanced IAV infection.We provided robust evidence to support the important role of Rab4b in facilitating IAV growth independent of the host innate immunity.Mechanism study revealed the involvement of Rab4b in the early steps of the IAV life cycle,including virus attachment,endocytosis of viral particles,virus-host membrane fusion,and nuclear import of viral nucleoprotein(NP).Furthermore,we found that Rab4b interacts with viral ribonucleoprotein(RNP)complexes,suggesting that Rab4b binds to RNP complex to facilitate viral replication.In summary,this work provided the first evidence to support the involvement of Rab4b in the IAV replication.Understanding the mechanisms underlying IAV and Rab4b interactions helps elucidate viral infection and pathogenesis and leads to the development of antiviral therapeutics.展开更多
基金The Shanghai Health and Family Planning Commission,No.20154Y0141Shanghai"Rising Stars of Medical Talent"Youth Development Program(Youth Medical Talents–Clinical Laboratory Practitioners Program)the Project of Huashan Hospital North,Fudan University,No.HSBY2019020.
文摘BACKGROUND Gastric cancer(GC)is one of the leading causes of cancer-related death worldwide.Although targeted therapies such as antibodies against human epidermal growth factor receptor 2 or vascular endothelial growth factor receptor 2 have been widely used in the treatment of metastatic cancer,the overall outcomes are poor.Therefore,elucidation of the mechanism underlying cancer progression is important to improve prognosis.Overexpression of the Rab5a gene has been confirmed to correlate with tumorigenesis of many cancers,but the mechanism underling,especially of GC,is still unclear.AIM To investigate the effects of Rab5a overexpression on the tumorigenesis of GC.METHODS First,the expression levels of Rab5a and Rab4a in primary tumorous tissues of GC patients diagnosed between 2015 and 2018 were analyzed.Then we constructed HGC-27 cell lines overexpressing green fluorescent protein-Rab5a or red fluorescent protein-Rab4a and investigated the interaction between Rab5a or Rab4a using Western blotting,co-immunoprecipitation,confocal microscopy,and colocalization analysis.Finally,epidermal growth factor-stimulated proliferation of these cell lines was analyzed using cell counting kit-8 cell viability assay.RESULTS Compared with normal gastric tissues,the expression levels of Rab5a and Rab4a increased progressively both in paracancerous tissues and in advanced cancerous tissues.Epidermal growth factor could promote the proliferation of HGC-27 cells,especially Rab5a-overexpressing HGC-27 cells.Notably,Rab5a and Rab4a cooverexpression promoted the proliferation of HGC-27 cells to the greatest extent.Further analysis identified a direct interaction between Rab5a and Rab4a in HGC-27 cells.CONCLUSION Co-overexpression of Rab5a and Rab4a in GC may promote the endosomal recycling of epidermal growth factor receptor,which in turn contributes to poor prognosis and tumor progression in GC patients.Inhibition of Rab5a or Rab4a expression might be a promising therapy for refractory GC.
基金supported by CAMS Innovation Fund for Medical Sciences(2021-I2M-1-038,2022-I2M-2-002)National Natural Science Foundation of China(81971950)+1 种基金the National Microbial Resource Center(NMRC-2020-3)the CAMS Collection Center of Pathogenic Microorganisms(CAMS-CCPM-A)for providing valuable reagents.
文摘Rab proteins are involved in all facets of the vesicular transport process and play significant roles in different steps of the viral life cycle.Rab4b is a pivotal player in the endocytic recycling of proteins,whereas its roles in viral replication are still largely unknown.Our earlier work identified Rab4b as a host factor required to replicate the influenza A virus(IAV).Here,we further validated the impact of Rab4b on viral replication by silencing or overexpressing Rab4b.The results showed that silencing Rab4b significantly decreased IAV and influenza B virus(IBV)production.Overexpression of Rab4b enhanced IAV infection.We provided robust evidence to support the important role of Rab4b in facilitating IAV growth independent of the host innate immunity.Mechanism study revealed the involvement of Rab4b in the early steps of the IAV life cycle,including virus attachment,endocytosis of viral particles,virus-host membrane fusion,and nuclear import of viral nucleoprotein(NP).Furthermore,we found that Rab4b interacts with viral ribonucleoprotein(RNP)complexes,suggesting that Rab4b binds to RNP complex to facilitate viral replication.In summary,this work provided the first evidence to support the involvement of Rab4b in the IAV replication.Understanding the mechanisms underlying IAV and Rab4b interactions helps elucidate viral infection and pathogenesis and leads to the development of antiviral therapeutics.
