Cell Line ; Clone Cells ; cytology ; metabolism ; Cloning, Molecular ; Genetic Vectors ; genetics ; Hepatocytes ; cytology ; metabolism ; Humans ; Simian virus 40 ; genetics ; Transfection

Immortalized human precartilaginous stem cells (IPSCs) were established to provide stable cell resource for the study of the molecular mechanism of gene targeting on the differentiation of PSCs. Plasmid pCMVSV40T/PUR containing simian virus 40 large T antigen gene (SV40Tag) was transfected into human PSCs by using lipofectin transfection. Colonies were isolated by puromycin selection and expanded by multiple passages. Immunohistochemistry, RT-PCR and Southern blotting were used to identify the transfected cells and to detect the expression and integration of SV40Tag in expanded cell lines. The positive colonies were isolated and subcultured, designated immortalized precartilaginous stem cells (IPSCs), which were confirmed as fibroblast growth factor receptor-3 (FGFR-3) positive cells by immunohistochemistry and RT-PCR. SV40Tag cDNA was found in cultured IPSCs of passage 8 by Southern blotting, and the expressions of SV40Tag mRNA and protein were confirmed by RT-PCR. These findings suggested that IPSCs strain with SV40Tag was constructed successfully.
Cartilage/*cytology ; Cell Proliferation ; Cell Transformation, Viral ; Cells, Cultured ; Fetus ; Simian virus 40/*genetics ; Stem Cells/*cytology ; Transfection

OBJECTIVETo immortalize human umbilical vein endothelial cells (HUVECs) by ectopic expression of the telomerase reverse transcriptase enzyme (hTERT), and by Simian Virus 40 Large T (SV40LT) antigen without malignant transformation.

METHODSTwo different retroviruses that contained hTERT/SV40LT cDNA fragment and drug resistance gene were constructed, and were used to transfect normal primary HUVECs. The transfected cells were screened with 500 microg/ml G418 and 4 microg/ml puromycin. Drug resistance cell clones were selected 3 days after transfection and cultured for further studies. An under inverted microscope and a scanning electron microscope were used to observe the morphology and growth of the cells. The expression of VIII factor and transfected DNA fragments were detected for identification of the endothelial origin and successful transfection. And the expression of E-selectin and endothelial lipase with or without the stimulus of TNF-alpha were also assayed to analyze the biological activity of the transfected cells.

RESULTSThe cells were homogenous, closely apposed, large, flat, and polygonal, displayed a characteristic ovoid nucleus with one or two nucleoli and formed monolayer with polygonal shape without overlapping. Immunocytochemical staining showed the existence of VIII factor. SV40LT/hTERT antigen expressed by the transfected cells was detected, while the contrasts had non-expression. Telomerase activity of the cell was detected in the transfected cells, which was 0.36 at 12 th passage and 0.38 at 50 th passage. However, the activity in the normal HUVECs was 1.12 at the first passage and 0.06 at the third passage assayed by PCR-ELISA. Both E-selectin and endothelial lipase were all specific in endothelial cells. The expressions of these two were also detected. And the expression of E-selectin can be up-regulated with the stimulus of TNF-alpha, while the expression of endothelial lipase was not unregulated significantly.

CONCLUSIONEctopic expression of hTERT and SV40LT can effectively immortalize HUVECs without tumorigenesis.

Antigens, Polyomavirus Transforming ; genetics ; Cell Line, Transformed ; Endothelial Cells ; cytology ; metabolism ; Humans ; Simian virus 40 ; immunology ; Telomerase ; genetics ; Transfection ; Umbilical Veins ; cytology

BACKGROUNDTo investigate the synergetic transactivating effects of HCV core and HBV X proteins.

METHODSHCV core and HBV X protein-expressing plasmids were constructed with the vector pcDNA3.1(-). The plasmids were transfected into HepG2 cells and cotransfected Hep2 cells with reporter plasmid Psv-lacZ by lipofectamine plus reagents. The virus proteins produced in transient expression system were detected at the transcription and translation levels. The activity of b-galactosidase was detected, which reflected the transactivating function of the proteins.

RESULTSThe expression of plasmids were detected in soluble protein cell extracts of transiently transfected HepG2 cells. HCV core protein activated the b-galactosidase expression at a value 4.9 times higher than the control, while HBV X protein activated at a value 3.5 times. It arrived at 9 times transfected with the plasmids simultaneously. The activating effect increased in relation to the amount of plasmids.

CONCLUSIONSThe results suggested that the two kinds of virus proteins have transactivating effect on SV40 early promoter/enhancer, and they acted synergistically. These contribute to explain the mechanisms of liver injury or tumorigenesis induced by HCV or/and HBV infection.

Animals ; Carcinoma, Hepatocellular ; virology ; Enhancer Elements, Genetic ; Hepacivirus ; genetics ; Hepatitis C Antigens ; genetics ; Humans ; Liver Neoplasms ; virology ; Promoter Regions, Genetic ; drug effects ; Simian virus 40 ; genetics ; Trans-Activators ; genetics ; Transcriptional Activation ; Viral Core Proteins ; genetics ; beta-Galactosidase ; biosynthesis ; genetics

OBJECTIVETo investigate whether simian virus 40 (SV40) was related to patients of malignant mesothelioma in China.

METHODSParaffin-embeded samples of 17 patients with malignant mesothelioma were collected. After isolation of DNA from paraffin blocks, polymerase chain reaction (PCR) analyses were performed using three different sets of primer for detection of SV40 large T antigen gene. These samples were also immunohistochemically evaluated for expression of SV40 TAg protein with two different anti-SV40 Tag (Pab101 and Ab-2).

RESULTSOnly one of the three primer pairs successfully amplified SV40 genome in three malignant mesothelioma samples. No immunopositive staining for SV40 TAg was found in any of the samples.

CONCLUSIONSThe study shows that malignant mesothelioma in China may be independent of SV40 infection.

Adult ; Aged ; Antigens, Viral, Tumor ; genetics ; metabolism ; China ; Female ; Host-Pathogen Interactions ; Humans ; Immunohistochemistry ; Male ; Mesothelioma ; pathology ; virology ; Middle Aged ; Polymerase Chain Reaction ; Polyomavirus Infections ; pathology ; virology ; Simian virus 40 ; genetics ; immunology ; physiology ; Tumor Virus Infections ; pathology ; virology ; Young Adult

SV40 large T antigen, a viral oncoprotein, is known to immortalize human diploid fibroblast by soaking up cellular RB and p53, but its frequency is extremely low. Additional genetic alteration is necessary for single-step immortalization. We attempted to find out what this alteration is by overexpressing cellular signal mediator genes; c-myc and cyclin D frequently amplified in many cancer cells. Overexpression of cyclin D did not affect the immortalization, but, overexpression of c-myc along with T antigen could immortalize normal human diploid fibroblast. Several cellular markers tested during immortalization process showed that p21, a cyclin-dependent kinase inhibitor and a marker of cellular senescence, disappeared in the life span-extended cells by T antigen and in the immortalized cells by c-myc. p21 was, however, elevated in the senescent cells and in the cells of crisis. Interestingly, p16 was upregulated whenever T antigen is overexpressed. Telomerase activity was also activated only in the immortalized cells. These results suggest that overexpression of c-myc contributes to immortalization of human diploid fibroblast by activating telomerase activity and suppressing p21 activity.
Antigens, Polyomavirus Transforming/genetics/*metabolism ; Biological Markers ; Cell Aging/*genetics ; Cell Transformation, Viral ; Cells, Cultured ; Cyclins/metabolism ; Diploidy ; Fibroblasts/*metabolism ; Genes, myc/*genetics ; Human ; Protein p16/metabolism ; Simian virus 40/genetics ; Support, Non-U.S. Gov't ; Telomerase/metabolism

SV40 large T antigen, a viral oncoprotein, is known to immortalize human diploid fibroblast by soaking up cellular RB and p53, but its frequency is extremely low. Additional genetic alteration is necessary for single-step immortalization. We attempted to find out what this alteration is by overexpressing cellular signal mediator genes; c-myc and cyclin D frequently amplified in many cancer cells. Overexpression of cyclin D did not affect the immortalization, but, overexpression of c-myc along with T antigen could immortalize normal human diploid fibroblast. Several cellular markers tested during immortalization process showed that p21, a cyclin-dependent kinase inhibitor and a marker of cellular senescence, disappeared in the life span-extended cells by T antigen and in the immortalized cells by c-myc. p21 was, however, elevated in the senescent cells and in the cells of crisis. Interestingly, p16 was upregulated whenever T antigen is overexpressed. Telomerase activity was also activated only in the immortalized cells. These results suggest that overexpression of c-myc contributes to immortalization of human diploid fibroblast by activating telomerase activity and suppressing p21 activity.
Antigens, Polyomavirus Transforming/genetics/*metabolism ; Biological Markers ; Cell Aging/*genetics ; Cell Transformation, Viral ; Cells, Cultured ; Cyclins/metabolism ; Diploidy ; Fibroblasts/*metabolism ; Genes, myc/*genetics ; Human ; Protein p16/metabolism ; Simian virus 40/genetics ; Support, Non-U.S. Gov't ; Telomerase/metabolism

Animals ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Endothelin-1 ; biosynthesis ; genetics ; Hepatocytes ; metabolism ; Liver ; cytology ; metabolism ; Liver Cirrhosis ; prevention & control ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Simian virus 40 ; genetics ; Transfection

Animals ; Cell Culture Techniques ; methods ; Cell Line ; Cell Proliferation ; Hepatocytes ; cytology ; metabolism ; Humans ; Liver ; cytology ; Liver Diseases ; therapy ; Liver, Artificial ; Mice ; Recombination, Genetic ; Simian virus 40 ; genetics ; Telomerase ; genetics ; metabolism ; Transfection ; Tumor Suppressor Protein p53 ; biosynthesis

Adenoviridae ; genetics ; Animals ; Cell Transplantation ; methods ; Gene Transfer Techniques ; Genetic Therapy ; methods ; Graft Rejection ; prevention & control ; Hepatocytes ; immunology ; transplantation ; Humans ; Liver ; metabolism ; Liver Failure ; surgery ; Simian virus 40 ; genetics ; Transfection ; Transplantation, Homologous