OBJECTIVESTo construct a novel virus-like particulate peptide-nucleic acid vaccine (VPNV) of human telomerase reverse transcriptase (hTERT), and to study its anti-liver cancer immunity.

METHODSA cationic antigenic peptide was synthesized and purified, and then human granulocyte macrophage colony stimulating factor (hGM-CSF) and TERT gene were cloned into the eukaryotic expression vector pTCAE. The peptide was combined with the nucleic acid vaccine to make a VPNV, which was transfected into eukaryotic cell COS-7. The immunogenicity of hGM-CSF and hTERT were detected using ELISA and Western blot. The efficacy of VPNV for inducing antigen specific CTL response was determined using the lactate dehydrogenase release method.

RESULTSVPNV was verified capable to trigger specific CTL responses and has shown a specific cytolytic activity to liver cancer cell HepG2.

CONCLUSIONA VPNV which can stimulate antigen specific CTL response was successfully constructed. This paves the way for our further investigation of anti-liver cancer immunity in mice.

Animals ; Cancer Vaccines ; immunology ; Cloning, Molecular ; Eukaryotic Cells ; metabolism ; Female ; Granulocyte-Macrophage Colony-Stimulating Factor ; genetics ; immunology ; Liver Neoplasms ; immunology ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Peptide Nucleic Acids ; genetics ; immunology ; Telomerase ; genetics ; immunology ; Vaccines, DNA ; immunology

OBJECTIVETo observe the functional changes of dendritic cells (DCs) after infection by recombinant retrovirus carrying human telomerase reverse transcriptase (hTERT) gene fragment.

METHODSInterleukin-12 (IL-12) levels in DC culture supernatant was determined by enzyme-linked immunosorbent assay (ELISA). The abilities of DCs infected with recombinant retrovirus carrying hTERT gene (hTERT-DCs) and non-infected DCs (N-DCs) to stimulate allogeneic lymphocyte proliferation were evaluated with mixed leukocytes reaction (MLR), and the surface markers of DCs including CD80, CD83, CD86 and HLA-DR were detected by flow cytometry. Cytotoxic T lymphocyte (CTL) assay was performed with CytoTox 96 non-radioactive cytoxicity assay.

RESULTSCompared with N-DCs, hTERT-DCs showed no significant changes in IL-12 secretion and capacity to stimulate allogeneic lymphocytes reaction, but had significantly lower CD83 expression. Specific CTLs induced by hTERT-DCs resulted in higher cytotoxicity against telomerase-positive target cells than that against the negative target cells.

CONCLUSIONInfection with the recombinant retrovirus carrying hTERT fragment may jeopardize the maturation of DCs, which, however, still retain their capacity to activate and stimulate lymphocyte proliferation and to prime autologous T lymphocytes to generate specific CTL against hTERT.

Cells, Cultured ; Dendritic Cells ; cytology ; immunology ; virology ; Genetic Vectors ; Humans ; Interleukin-12 ; biosynthesis ; Recombination, Genetic ; Retroviridae ; genetics ; metabolism ; T-Lymphocytes, Cytotoxic ; immunology ; Telomerase ; biosynthesis ; genetics

OBJECTIVETo explore the regulatory effects of hTERT and TEP1 on telomerase activity in hematopoiesis.

METHODSThe hTERT and TEP1 mRNA expression was detected by RT-PCR and the telomerase activi-ty by TRAP.

RESULTSIn mononuclear cells (MNC) and CD(34)(-) cells, no detectable telomerase activity and hTERT mRNA expression were found. CD(34)(+) cells showed hTERT expression and a low level telomerase activity. TEP1 mRNA was detected in MNC, CD(34)(-) and CD(34)(+) cells with no significant difference in the expression level. In the CD(34)(+) cells cultured in vitro with growth factors for 7 days, the telomerase activity and the expression of hTERT mRNA were upregulated, but were downregulated in the long time culture. No significant changes in TEP1 expression was observed.

CONCLUSIONIn the course of hematopoiesis, hTERT mRNA expression was in accordance with telomerase activity, hTERT gene plays a crucial role in the expression of telomerase activity, while TEP1 gene plays, if any, a much smaller role.

Antigens, CD34 ; immunology ; Carrier Proteins ; genetics ; DNA-Binding Proteins ; Fetal Blood ; cytology ; metabolism ; Gene Expression ; Humans ; Leukocytes, Mononuclear ; cytology ; immunology ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Stem Cells ; cytology ; metabolism ; Telomerase ; genetics

BACKGROUND/AIMS: Telomeres are simple repeat elements located at each chromosome end of eukaryotic cells. The main function of telomeres is to cap the chromosome end and protect it from enzymatic attack. Telomerase that facilitates the synthesis of telomere has been detected in not only cancer but also precancerous lesion. In this study, we compared the telomerase expression between low grade and high grade colorectal tubular adenoma. METHODS: Among thissues from forty eight patients with colorectal tubular adenoma (23 low grade and 25 high grade colorectal dysplasia), telomerase expressions were evaluated by immunohistochemical staining. RESULTS: We classified 48 patients into two groups by the extent of nuclei staining pattern. High telomerase expression was a group which showed staining nucleus pattern above 50% in tubular adenoma. Low telomerase expression was a group which showed staining pattern nucleus below 50%. Twelve in 25 high grade colorectal dysplasia showed high telomerase expression (48%). Only one in 23 low grade colorectal dysplasia showed high telomerase expression (4%). Telomerase expression was much higher in the tissues from the patients with high grade than in those with low grade colorectal dysplasia (p<0.05). CONCLUSIONS: Activation of telomerase may be related to the malignant potential in colorectal epithelial cells. Further studies are needed to define the role of telomerase in colorectal tumorigenesis.
Adenocarcinoma/*enzymology/pathology ; Adult ; Aged ; Colorectal Neoplasms/*enzymology/pathology ; Female ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Neoplasm Staging ; Retrospective Studies ; Telomerase/immunology/*metabolism

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

OBJECTIVETo investigate the telomerase activity and the telomere length in CD4(+), CD8(+) and CD19(+) lymphocytes from patients with systemic lupus erythematosus (SLE).

METHODSTelomerase activity of CD4(+), CD8(+) and CD19(+) cells from patients with SLE and normal controls was examined by telomeric repeats amplification protocol. Telomere length in those cells was measured by Southern blot method.

RESULTCD4(+), CD8(+) and CD19(+) cells in patients with SLE showed high telomerase activity, but only telomerase activity of CD19(+) cells was significantly higher than that in controls. The length of telomere in CD4(+) and CD8(+) cells was significantly shorter than that in controls, but not in CD19(+) cells.

CONCLUSIONHigher telomerase activity in CD19(+) cells and shortened telomere length in CD4(+) and CD8(+) cells of patients with SLE may be associated with pathogenesis of SLE.

Adolescent ; Adult ; Antigens, CD19 ; immunology ; CD4-Positive T-Lymphocytes ; enzymology ; CD8-Positive T-Lymphocytes ; enzymology ; Female ; Humans ; Lupus Erythematosus, Systemic ; enzymology ; immunology ; Lymphocytes ; enzymology ; Male ; Middle Aged ; Telomerase ; metabolism ; Telomere ; genetics

OBJECTIVETo investigate the effects of dendritic cells (DCs) infected with adenovirus vector encoding mTERT on induction of mTERT antigen specific immunity against H22 hepatoma in vivo.

METHODSForty Bal B/c mice were subcutaneously immunized with Ad-mTERT infected DC. Cytotoxicity of mTERT specific CTL was determined by 51Cr release assay. IL-2 and IFN-gamma were tested by ELISA. IFN-gamma ELISPOT assays were performed for measuring antigen specific IFN-gamma production by T cells. Tumor size and survival of the immunized mice were recorded and evaluated whether preexisting hepatoma metastases could be supressed after immunization with mTERT-expressing DCs.

RESULTSThe lytic activity of CTL, IL-2 (871.25 pg/ml), IFN-gamma (169.15 ng/ml) and IFN-gamma secreting cells (378/10(6) spleen cells) elicited by the Ad-mTERT infected DCs were much stronger and higher than that by Ad-GFP group (131.6 pg/ml, 15.4 ng/ml, 36/10(6) spleen cells, P<0.05), DC group (71.3 pg/ml, 10.5 ng/ml, 21/10(6) spleen cells, P<0.05), PBS group (65.8 pg/ml, 7.4 ng/ml, 18/10(6) spleen cells, P<0.05). In prophylaxis and treatment experiment the Ad-mTERT/DCs immunized mice lived significantly longer than other groups, demonstrating that primary DCs were genetically modified to express the mTERT antigen and could suppress the tumor growth.

CONCLUSIONAdenovirus vector mediated mTERT infected DCs can effectively induce mTERT antigen specific antitumor activity, and can induce protective and therapeutic antitumor immunity.

Adenoviridae ; genetics ; Animals ; Cell Line, Tumor ; Dendritic Cells ; immunology ; metabolism ; Female ; Genetic Vectors ; Immunization ; Interferon-gamma ; Interleukin-2 ; Liver Neoplasms, Experimental ; immunology ; pathology ; Male ; Mice ; Mice, Inbred BALB C ; Neoplasm Transplantation ; Recombinant Proteins ; genetics ; metabolism ; T-Lymphocytes, Cytotoxic ; immunology ; Telomerase ; immunology ; metabolism ; Tumor Burden

OBJECTIVETo establish human colorectal crypt cell line.

METHODSColorectal crypt cells were separated from human fetal gut by dispase I digestion, AKP-negative cells from fetal colorectal crypt were collected and cultured on Matrigel matrix. Subsequently the primary cultured cells were transfected with recombinant retrovirus containing human telomerase reverse transcriptase (hTERT) and simian virus 40 large T antigen (SV40 LT) in 48 h. The characterization of immortalized cells was identified after the transfection and cells were screened with antibiotics for 12 approximately 16 weeks and expanded.

RESULTSMucin, cytokeratin-pan, 8, 19 were presented in immortalized cells by immunohistochemical staining; ectopic expressions of both hTERT and SV40 LT were also found in immortalized cells by Western blotting. Agarose electrophoresis showed that the cells expressed Musashi-1 mRNA. No evidence of carcinogenesis was found in nude mouse experiment and soft-agarose cloning test.

CONCLUSIONThe immortalized human colorectal crypt cells were characterized and the established cell line may be an ideal target for carcinogenesis study in vitro.

Cell Line, Transformed ; Colon ; cytology ; DNA-Binding Proteins ; Fetus ; Humans ; RNA, Neoplasm ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Simian virus 40 ; immunology ; Stem Cells ; cytology ; Telomerase ; genetics ; metabolism ; Transcription, Genetic ; Transfection ; methods

OBJECTIVETo construct SD rat immortalized dental follicle cells (rDFC) induced by simian virus 40 large tumor antigen (SV40Tag) gene to provide a reliable cell source for periodontal tissue engineering research.

METHODSThe rDFC was isolated by tissue mass method combined with enzyme digestion method and evaluated by immunohistochemistry. Cell293 were transfected with plasmid pSSR69/pAmpho containing SV40Tag gene by mediating liposome. Normal rDFC were infected with virus-contained supernate and the successfully transfected cell lines were screened with hygromycin, and positive clones were cultured. While non-transfected cells served as negative controls, the cell morphology was observed, the proliferation characteristics was evaluated by calculating cell population. The expression of SV40Tag gene and telomerase in cells was detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting respectively. The biological property of immortalized rDFC was assessed with calculating formation rate of flat cloning, soft agar colony formation test and tumor-forming test.

RESULTSMorphology of immortalized rDFC was not different from that of normal rDFC. The RT-PCR results of SV40Tag revealed amplification band at 357 bp, while no band was seen in the normal cells. The expression of telomerase in immortalized rDFC was higher than that in normal rDFC. The two groups had no significant difference in growth curves, but the immortalized rDFC exhibited stronger proliferative activity. No significant differences of formation rate in flat cloning were observed between the immortalized rDFC [34% (33/96)] and normal rDFC at passage four [22% (21/96)] (χ(2) = 3.71, P > 0.05). No cell cloning was seen in soft agar and the tumor formation was not observed in nude mice.

CONCLUSIONSThe rDFC induced by SV40Tag gene could be cultured and passaged in vitro, which retained the stable proliferation and differentiation characteristics and could be used for periodontal tissue engineering research.

Animals ; Antigens, Viral, Tumor ; genetics ; metabolism ; Cell Differentiation ; Cell Proliferation ; Cell Transformation, Viral ; Cells, Cultured ; Dental Sac ; cytology ; immunology ; metabolism ; HEK293 Cells ; Humans ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Plasmids ; Rats ; Rats, Sprague-Dawley ; Simian virus 40 ; genetics ; immunology ; Telomerase ; metabolism ; Transfection