AIM:To investigate the relationship between late SV40 factor(LSF)and Notch signaling in the development and progress of hepatocellular carcinoma(HCC).METHODS:Liver cancer tissue specimens from 25 patients were analyze...AIM:To investigate the relationship between late SV40 factor(LSF)and Notch signaling in the development and progress of hepatocellular carcinoma(HCC).METHODS:Liver cancer tissue specimens from 25 patients were analyzed for Notch-1 and LSF expression by immunohistochemistry.The correlation between expression and the biological effects of Notch-1 and LSF were analyzed using genetic and pharmacological strategies in HCC cell lines and human normal cell lines,including hepatic stellate cells(HSC)and human embryonic kidney epithelial cells(HEK).RESULTS:Immunohistochemistry showed that both Notch-1 and LSF were significantly upregulated in HCC samples(76%,19/25,P<0.0001 and 84%,21/25,P<0.0001,respectively)compared with non-cancer samples.Activation of Notch-1 by exogenous transfection of Notch1 intracellular domain increased LSF expression in HSC and HEK cells to levels similar to those seen in HepG2 cells.Furthermore,blocking Notch-1 activation with aγ-secretase inhibitor,DAPT,downregulated LSF expression in HepG2 cells.Additionally,a biological behavior assay showed that forced overexpression of LSF promoted HepG2 cell proliferation and invasion.CONCLUSION:LSF is a key mediator of the Notch signaling pathway,suggesting that it might be a novel therapeutic target for the treatment of HCC.展开更多
Epigenetics of human cancer becomes an area of emerging research direction due to a growing understanding ofspecific epigenetic pathways and rapid development of detection technologies. Aberrant promoter hypermethylat...Epigenetics of human cancer becomes an area of emerging research direction due to a growing understanding ofspecific epigenetic pathways and rapid development of detection technologies. Aberrant promoter hypermethylation is aprevalent phenonmena in human cancers. Tumor suppressor genes are often hypermethylated due to the increasedactivity or deregulation of DNMTs. Increasing evidence also reveals that viral genes are one of the key players inregulating DNA methylation. In this review, we will focus on hypermethylation and tumor suppressor gene silencing andthe signal pathways that are involved, particularly in cancers closely associated with the hepatitis B virus, simian virus40 (SV40), and Epstein-Barr virus. In addition, we will discuss current technologies for genome-wide detection ofepigenetically regulated targets, which allow for systematic DNA hypermethylation analysis. The study of epigeneticchanges should provide a global view of gene profile in cancer, and epigenetic markers could be used for early detection,prognosis, and therapy of cancer.展开更多
Background Although DNA vaccine is considered as the next generation of vaccine, most DNA vaccine candidates are still suffering from the relatively weak immunogenicity despite the increased dosage of plasmid DNA admi...Background Although DNA vaccine is considered as the next generation of vaccine, most DNA vaccine candidates are still suffering from the relatively weak immunogenicity despite the increased dosage of plasmid DNA administered. In order to enhance the immune responses elicited by a codon-optimized HIV gag DNA vaccine, a modified plasmid vector pDRVI1.0 and a booster immunization with replicating Tiantan vaccinia （RTV） strain expressing the same gene were employed. Methods Vector pDRVI1.0 was constructed through inserting the 72-bp element from the SV40 enhancer, which was reported promoting nuclear transport of plasmid DNA, to the upstream of cytomegalovirus enhancer/promoter region of the plasmid vector pVR1012. Gene expression levels from expression plasmids based on pDRVI1.0 and pVR1012 were tested. Humoral and cellular immune responses induced by DNA vaccine alone or DNA prime-RTV boost regimen were determined in mice. Results It was shown that the 72-bp element significantly enhanced the gene expression level in non-dividing cells. gag-specific humoral and cellular immune responses induced by DNA vaccination were both significantly improved, while the Thl/Th2 balance was not obviously affected by the 72-bp element. RTV boosting further significantly enhanced DNA vaccine-palmed antibody and T cell responses in a Thl-biased manner. Conclusions The 72-bp SV40 enhancer element should be included in the DNA vaccine vector and RTV strain is a very efficient live vector for boosting immunization.展开更多
Neurogenesis takes place in the adult mammalian brain in three areas:Subgranular zone of the dentate gyrus(DG);subventricular zone of the lateral ventricle;olfactory bulb.Different molecular markers can be used to cha...Neurogenesis takes place in the adult mammalian brain in three areas:Subgranular zone of the dentate gyrus(DG);subventricular zone of the lateral ventricle;olfactory bulb.Different molecular markers can be used to characterizethe cells involved in adult neurogenesis.It has been recently suggested that a population of bone marrow(BM)progenitor cells may migrate to the brain and differentiate into neuronal lineage.To explore this hypothesis,we injected recombinant SV40-derived vectors into the BM and followed the potential migration of the transduced cells.Long-term BM-directed gene transfer using recombinant SV40-derived vectors leads to expression of the genes delivered to the BM firstly in circulating cells,then after several months in mature neurons and microglial cells,and thus without central nervous system(CNS)lesion.Most of transgene-expressing cells expressed NeuN,a marker of mature neurons.Thus,BM-derived cells may function as progenitors of CNS cells in adult animals.The mechanism by which the cells from the BM come to be neurons remains to be determined.Although the observed gradual increase in transgene-expressing neurons over 16mo suggests that the pathway involved differentiation of BM-resident cells into neurons,cell fusion as the principal route cannot be totally ruled out.Additional studies using similar viral vectors showed that BM-derived progenitor cells migrating in the CNS express markers of neuronal precursors or immature neurons.Transgene-positive cells were found in the subgranular zone of the DG of the hippocampus 16 mo after intramarrow injection of the vector.In addition to cells expressing markers of mature neurons,transgene-positive cells were also positive for nestin and doublecortin,molecules expressed by developing neuronal cells.These cells were actively proliferating,as shown by short term BrdU incorporation studies.Inducing seizures by using kainic acid increased the number of BM progenitor cells transduced by SV40vectors migrating to the hippocampus,and these cells were seen at展开更多
Glomerular podocytes are highly specialized epithelial cells and play an essential role in establishing the selective permeability of the glomerular filtration barrier of kidney.Maintaining the viability and structura...Glomerular podocytes are highly specialized epithelial cells and play an essential role in establishing the selective permeability of the glomerular filtration barrier of kidney.Maintaining the viability and structural integrity of podocytes is critical to the clinical management of glomerular diseases,which requires a thorough understanding of podocyte cell biology.As mature podocytes lose proliferative capacity,a conditionally SV40 mutant tsA58-immortalized mouse podocyte line(designated as tsPC)was established from the Immortomouse over 20 years ago.However,the utility of the tsPC cells is hampered by the practical inconvenience of culturing these cells.In this study,we establish a user-friendly and reversibly-immortalized mouse podocyte line(designated as imPOD),on the basis of the tsPC cells by stably expressing the wildtype SV40 T-antigen,which is flanked with FRT sites.We show the imPOD cells exhibit long-term high proliferative activity,which can be effectively reversed by FLP recombinase.The imPOD cells express most podocyte-related markers,including WT-1,Nephrin,Tubulin and Vinculin,but not differentiation marker Synaptopodin.The imPOD cells do not form tumor-like masses in vivo.We further demonstrate that TGFb1 induces a podocyte injury-like response in the FLP-reverted imPOD cells by suppressing the expression of slit diaphragm-associated proteins P-Cadherin and ZO-1 and upregulating the expression of mesenchymal markers,a-SMA,Vimentin and Nestin,as well as fibrogenic factors CTGF and Col1a1.Collectively,our results strongly demonstrate that the newly engineered im-POD cells should be a valuable tool to study podocyte biology both under normal and under pathological conditions.展开更多
基金Supported by The National Natural Science Foundation of China,No.30470780
文摘AIM:To investigate the relationship between late SV40 factor(LSF)and Notch signaling in the development and progress of hepatocellular carcinoma(HCC).METHODS:Liver cancer tissue specimens from 25 patients were analyzed for Notch-1 and LSF expression by immunohistochemistry.The correlation between expression and the biological effects of Notch-1 and LSF were analyzed using genetic and pharmacological strategies in HCC cell lines and human normal cell lines,including hepatic stellate cells(HSC)and human embryonic kidney epithelial cells(HEK).RESULTS:Immunohistochemistry showed that both Notch-1 and LSF were significantly upregulated in HCC samples(76%,19/25,P<0.0001 and 84%,21/25,P<0.0001,respectively)compared with non-cancer samples.Activation of Notch-1 by exogenous transfection of Notch1 intracellular domain increased LSF expression in HSC and HEK cells to levels similar to those seen in HepG2 cells.Furthermore,blocking Notch-1 activation with aγ-secretase inhibitor,DAPT,downregulated LSF expression in HepG2 cells.Additionally,a biological behavior assay showed that forced overexpression of LSF promoted HepG2 cell proliferation and invasion.CONCLUSION:LSF is a key mediator of the Notch signaling pathway,suggesting that it might be a novel therapeutic target for the treatment of HCC.
文摘Epigenetics of human cancer becomes an area of emerging research direction due to a growing understanding ofspecific epigenetic pathways and rapid development of detection technologies. Aberrant promoter hypermethylation is aprevalent phenonmena in human cancers. Tumor suppressor genes are often hypermethylated due to the increasedactivity or deregulation of DNMTs. Increasing evidence also reveals that viral genes are one of the key players inregulating DNA methylation. In this review, we will focus on hypermethylation and tumor suppressor gene silencing andthe signal pathways that are involved, particularly in cancers closely associated with the hepatitis B virus, simian virus40 (SV40), and Epstein-Barr virus. In addition, we will discuss current technologies for genome-wide detection ofepigenetically regulated targets, which allow for systematic DNA hypermethylation analysis. The study of epigeneticchanges should provide a global view of gene profile in cancer, and epigenetic markers could be used for early detection,prognosis, and therapy of cancer.
基金This project was supported by the CIPRA Program granted by the National Institute of Health(No.1 U19 AI51915-02)a grant from the National High Technology Research and Development Program of China(863 Program,No.2003AA219100)
文摘Background Although DNA vaccine is considered as the next generation of vaccine, most DNA vaccine candidates are still suffering from the relatively weak immunogenicity despite the increased dosage of plasmid DNA administered. In order to enhance the immune responses elicited by a codon-optimized HIV gag DNA vaccine, a modified plasmid vector pDRVI1.0 and a booster immunization with replicating Tiantan vaccinia （RTV） strain expressing the same gene were employed. Methods Vector pDRVI1.0 was constructed through inserting the 72-bp element from the SV40 enhancer, which was reported promoting nuclear transport of plasmid DNA, to the upstream of cytomegalovirus enhancer/promoter region of the plasmid vector pVR1012. Gene expression levels from expression plasmids based on pDRVI1.0 and pVR1012 were tested. Humoral and cellular immune responses induced by DNA vaccine alone or DNA prime-RTV boost regimen were determined in mice. Results It was shown that the 72-bp element significantly enhanced the gene expression level in non-dividing cells. gag-specific humoral and cellular immune responses induced by DNA vaccination were both significantly improved, while the Thl/Th2 balance was not obviously affected by the 72-bp element. RTV boosting further significantly enhanced DNA vaccine-palmed antibody and T cell responses in a Thl-biased manner. Conclusions The 72-bp SV40 enhancer element should be included in the DNA vaccine vector and RTV strain is a very efficient live vector for boosting immunization.
文摘Neurogenesis takes place in the adult mammalian brain in three areas:Subgranular zone of the dentate gyrus(DG);subventricular zone of the lateral ventricle;olfactory bulb.Different molecular markers can be used to characterizethe cells involved in adult neurogenesis.It has been recently suggested that a population of bone marrow(BM)progenitor cells may migrate to the brain and differentiate into neuronal lineage.To explore this hypothesis,we injected recombinant SV40-derived vectors into the BM and followed the potential migration of the transduced cells.Long-term BM-directed gene transfer using recombinant SV40-derived vectors leads to expression of the genes delivered to the BM firstly in circulating cells,then after several months in mature neurons and microglial cells,and thus without central nervous system(CNS)lesion.Most of transgene-expressing cells expressed NeuN,a marker of mature neurons.Thus,BM-derived cells may function as progenitors of CNS cells in adult animals.The mechanism by which the cells from the BM come to be neurons remains to be determined.Although the observed gradual increase in transgene-expressing neurons over 16mo suggests that the pathway involved differentiation of BM-resident cells into neurons,cell fusion as the principal route cannot be totally ruled out.Additional studies using similar viral vectors showed that BM-derived progenitor cells migrating in the CNS express markers of neuronal precursors or immature neurons.Transgene-positive cells were found in the subgranular zone of the DG of the hippocampus 16 mo after intramarrow injection of the vector.In addition to cells expressing markers of mature neurons,transgene-positive cells were also positive for nestin and doublecortin,molecules expressed by developing neuronal cells.These cells were actively proliferating,as shown by short term BrdU incorporation studies.Inducing seizures by using kainic acid increased the number of BM progenitor cells transduced by SV40vectors migrating to the hippocampus,and these cells were seen at
基金The reported work was supported in part by research grants from the National Institutes of Health(CA226303 to TCH)the National Key Research and Development Program of China(2016YFC1000803 and 2011CB707906 to TCH)+1 种基金This project was also supported in part by The University of Chicago Cancer Center Support Grant(P30CA014599)the National Center for Advancing Translational Sciences of the National Institutes of Health through Grant Number UL1 TR000430.
文摘Glomerular podocytes are highly specialized epithelial cells and play an essential role in establishing the selective permeability of the glomerular filtration barrier of kidney.Maintaining the viability and structural integrity of podocytes is critical to the clinical management of glomerular diseases,which requires a thorough understanding of podocyte cell biology.As mature podocytes lose proliferative capacity,a conditionally SV40 mutant tsA58-immortalized mouse podocyte line(designated as tsPC)was established from the Immortomouse over 20 years ago.However,the utility of the tsPC cells is hampered by the practical inconvenience of culturing these cells.In this study,we establish a user-friendly and reversibly-immortalized mouse podocyte line(designated as imPOD),on the basis of the tsPC cells by stably expressing the wildtype SV40 T-antigen,which is flanked with FRT sites.We show the imPOD cells exhibit long-term high proliferative activity,which can be effectively reversed by FLP recombinase.The imPOD cells express most podocyte-related markers,including WT-1,Nephrin,Tubulin and Vinculin,but not differentiation marker Synaptopodin.The imPOD cells do not form tumor-like masses in vivo.We further demonstrate that TGFb1 induces a podocyte injury-like response in the FLP-reverted imPOD cells by suppressing the expression of slit diaphragm-associated proteins P-Cadherin and ZO-1 and upregulating the expression of mesenchymal markers,a-SMA,Vimentin and Nestin,as well as fibrogenic factors CTGF and Col1a1.Collectively,our results strongly demonstrate that the newly engineered im-POD cells should be a valuable tool to study podocyte biology both under normal and under pathological conditions.
