OBJECTIVE: To analysis the biological characteristics of human fibroblasts transfected by human telomerase reverse transcriptase (hTERT) eucaryotic expression plasmid pGRN145. METHODS: Fibroblasts from children’s foreskin were isolated and cultured in vitro, and the fibroblasts were transfected by pGRN145 with Lipofec-tAMINE PLUS Reagent. After strict screening of hygromycin B, the positive clones were subcultured. The telomerase activity was detected by RT-PCR and TRAP-PCR technique. The cell generation cycle and apoptosis rate were detected by flow cytometry to investigate the proliferative characteristics after transfection, and the chromosome karyotype of transformed cells was analyzed. The collagen secreted by transformed cells was detected by immunohistochemical staining. RESULTS: The morphological properties of fibroblasts did not change obviously after transfection. There were telomerase activity in transfected fibroblasts, while it could not be detected in pre-transfection fibroblasts. The cell generation cycle had no obvious changes between pre-transfection and post-transfection. However, the apoptosis rate of transfected fibroblasts were decreased compared with that of pre-transfection. The fibroblasts transfected by pGRN145 maintained the normal diploid karyotype, as well as the cells could normally secret type I and III collagen. CONCLUSION: The human fibroblasts transfected by pGRN145 has telomerase activity with prolonged life span of culture, which preliminarily proves the availability of establishing standard seeding cell lines of tissue engineering by hTERT plasmid transfection techniques.
OBJECTIVE: To prevent the senescence of ’seed cells’ for tissue engineering, the life span of human fibroblasts is extended by reconstitution of telomerase activity, and the osteogenic potential of these fibroblasts are tested. METHODS: The pGRN145 plasmids encoding human telomerase reverse transcriptase (hTERT) were introduced into the normal human primary fibroblasts by electroporation. Telomerase activity was analyzed by TRAP-PCR assay. The beta-galactosidase stain was used to indicate the signs of cell senescence. The hTERT positive fibroblasts were then induced to form bone nodules. The bone nodules were stained by tetracycline and Alizarin Red S. RESULTS: Stable telomerase activity could be detected in the transfected fibroblasts and no signs of cell senescence were found in the fibroblasts cultured for more than 50 doublings. The hTERT positive fibroblasts could form bone nodules when they were cultured in vitro induced by bone morphogentic protein 2 and tumor necrosis factor-alpha. CONCLUSION: The fibroblasts with reconstituted telomerase activity reserve their osteogenic potential.
ObjectiveTo explore the effects of exogenous estrogen receptor β1 (ERβ1) gene on the expression of human telomerase reverse transcriptase (hTERT) as well as the changes of proliferation ability in MDA-MB-231 cell line by transfecting recombinant eukaryotic expressing vector containing ERβ1 cDNA into human breast cancer MDA-MB-231 cell. MethodsRecombinant eukaryotic expressing vector containing ERβ1 cDNA was transfected into human breast cancer MDA-MB-231 cell by using cationic liposome as transfecting agent (acted as pcDNA3.1ERβ1 transfection group), empty vector group and non-transfection group acted as controls. The expression levels in both the mRNA and protein of both the ERβ1 and hTERT were tested by real-time PCR and Western blot, respectively. The change of proliferation ability in MDA-MB-231 cell was displayed by cell growth curve, and the change of cell apoptosis was detected by flow cytometry. ResultsThe expression level of ERβ1 mRNA in the pcDNA3.1-ERβ1 transfection group (0.449±0.077) significantly increased as compared with the nontransfection group (0.153±0.035) or the empty vector group (0.160±0.020), P=0.001 or P=0.000. The expression level of ERβ1 protein in the pcDNA3.1-ERβ1 transfection group (0.847±0.065) significantly increased as compared with the non-transfection group (0.356±0.050) or the empty vector group (0.390±0.030), P=0.001 or P=0.000. The expression level of hTERT mRNA in the pcDNA3.1-ERβ1 transfection group (0.127±0.020) significantly decreased as compared with the non-transfection group (0.283±0.025) or the empty vector group (0.283±0.049), P=0.001 or P=0.002. The expression level of hTERT protein in the pcDNA3.1-ERβ1 transfection group (0.147±0.023) significantly decreased as compared with the non-transfection group (0.783±0.025) or the empty vector group (0.802±0.019), P=0.001 or P=0.002. The rate of cell apoptosis in the pcDNA3.1-ERβ1 transfection group 〔(6.15±0.94)%〕 was higher than that in the non-transfection group 〔(1.41±0.42)%〕， P=0.001. Cell proliferation curve showed that proliferation ability significantly decreased in the pcDNA3.1-ERβ1 transfected groups as compared with the non-transfection group (Plt;0.05). ConclusionERβ1 could inhibit cell growth of human breast cancer MDA-MB-231 cell by down-regulating the expression of hTERT.
Objective To introduce telomeres, telomerase and their expression in gastric carcinoma.MethodsThe related literatures were collected and reviewed.Rsults In summary, telomerase activity could be detected in 85%-90% of gastric cancer. Moreover, the patient with telomerase-positive tumors showed poorer prognosis than those with telomerase-negative tumours, indicating that telomerase-positive gastric cancer might have more malignant potential. ConclusionKnowledge of telomerase activity in gastric cancer may be useful in cancer diagnosis, as well as a prognostic indicator of clinical outcome. Future development of drugs aimed at telomerase inhibition may potentially provide a therapy with relatively less side effects.
【Abstract】Objective To explore the relation between the expression of telomerase and DNA ploidy with biliarypancreatic system cancer, so as to find a better way to diagnose and distinguish jaundice between malignance and benign disease.Methods Endoscopic retrograde cholangiopancreatography (ERCP) were performed before operation in patients with obstructive jaundice. The bile and pancreatice juice were collected before ERCP. Biopsy specimens from part of patients were obtained during ERCP. All cancer specimens were possessed once again during operation and were assessed by the activity of telomerase and DNA ploidy. Results ① Telomerase positive rate 〔87.50%(56/64)〕 of tissue specimens in malignant obstructive jaundice were higher than that in benign obstructive jaundice 〔3.33%(2/60)〕，P=0.000. ② Telomerase positive rate〔71.88%(46/64)〕of Bile and pancreatice juice in malignant obstructive jaundice were higher than that in benign obstructive jaundice 〔3.33%(2/60)〕， P=0.000, tissue specimens obtained by endoscopy with malignant obstructive jaundice had detectable telomerase activity, positive rate was 83.33%（20/24）. ③ The rate of DNA heteroploid with malignant obstructive jaundice was 62.50%（40/64）, that of diploid can be seen in all patients with benign obstructive jaundice, the difference was statistically significant (P=0.000). ④ The rate of telomerase positive and DNA heteroploid in high differentiation tumor were significantly lower than in middlelow differentiation tumor （P=0.028，P=0.001）.Conclusion Applying the duodenoscope we collected the bile and pancreatic fluid before operation and obtain biopsy specimens whose telomerase activity and DNA ploid were detected. This is simple, safe, quick method which can identify the malignant and benign obstructive jaundice.
ObjectiveTo investigate the relationship between the expressions of B-cell-specific monoclonal leukemia virus insert site 1 (Bmi1) and human telomerase reverse transcriptase (hTERT) genes and the proliferative capacity of stem cells. MethodsCord blood CD34+ cells were cultured in IMDM medium containing fetal bovine serum, stem cell growth factor, thrombopoietin, and Fms-like tyrosine kinase 3 ligand during a 28-day ex vivo expansion process, while the expansion fold, specific growth rate, and the colony-forming efficiency were monitored. Then the Bmi1 and hTERT mRNA expressions in CD34+ cells were detected by fluorescence quantitative PCR, and the relations between the expressions and the cell proliferative capacity were analyzed. ResultsCD34+ cells expanded (20.1 ± 3.5) folds during the 28-day culture, while the proportion declined from 95.5% ± 2.6% before culture to 2.1% ± 0.4%. Both the specific growth rate and colony-forming efficiency of CD34+ cells declined significantly after 7 days, while the expression levels of Bmi1 and hTERT mRNA in CD34+ cells reached top at 7 days and declined gradually thereafter. ConclusionThe expressions of Bmi1 and hTERT genes may have a close relation to the proliferative capacity of CD34+ cells.
Objective To investigate the expression of telomerase reverse transcriptase (TERT) and cell apoptosis in neonatal rats with hypoxia ischemia brain damage (HIBD). Methods A total of 42 7-day-old SD rats (12-18 g, male or female) were randomly allocated into sham-operation group (n=6) and hypoxia-ischemia (HI) group (n=36). In HI group, the rats were anesthetized with ethylether. The right common carotid artery (CCA) was exposed and permanently l igated with a 7-0silk suture through a midl ine cervical incision. A duration of 2.5 hours of hypoxia (8%O2 / 92%N2) was used to produce HIBD model. For sham-operation group, the CCA was exposed without l igation or hypoxia. The brain tissues were harvested at 4, 8, 12, 24, 48, and 72 hours after completion of an HI insult. The expressions of TERT and CC3 were detected by immunohistochemical staining. The apoptosis cells were detected with TUNEL staining method. Results The expression of TERT was increased at 4 hours after HI injury, significantly increased at 24-48 hours and then decreased at 72 hours. The expression of CC3 was increased at 4 hours after HI injury, significantly increased at 24 hours and still maintained high expression at 48 hours and 72 hours. However, in the sham-operation group, both the expressions of TERT and CC3 were extremely low. The expression of TERT and CC3 were higher in the HI group than in the sham-operation group at different time points, and the differences were significant (P lt; 0.05). The TUNEL staining showed that the positive cells in hippocampus and cortical areas were increased at 4 hours after HI injury, significantly increased at 24-48 hours and maintained a high level at 72 hours. However, there was few positive cells in the sham-operation group. There were significant differences between the HI group and the sham-operation group at different time points (P lt; 0.05). Conclusion TERT could be induced by HI in neonatal rats, and might have a protective role in regulating the cell apoptosis in the neonatal HIBD.
In recent years, the incidence of thyroid cancer has been increasing. Researchers around the world have begun to pay more attention to the exploration of its pathogenesis, disease evolution and prognosis. Among them, research in the field of gene molecules has become a hotspot, which includes the mutations of v-raf murine sarcoma viral oncogene homologue B1 (BRAF) and the telomerase reverse transcriptase (TERT) promoter. However, this field is not mature, and there are many problems and challenges need to be solved. This paper explores the value of BRAF mutation in the treatment, recurrence, mortality and prognosis of papillary thyroid carcinoma. In addition, we also explore the relationship between BRAF mutation and TERT promoter mutations and their influences in thyroid cancer. We hope this paper could help later scholars understand the current situation in this field and find a research direction in the future.
【Abstract】Objective To study the difference of telomerase activity in the common thyroid lesions . Methods The telomerase activity was detected in 19 patients with thyroid carcinomas, 15 samples adjacent to thyroid carcinomas，21 specimens of thyromas, 17 cases of nodular goiters and 13 pieces of normal thyroid tissues by telomeric repeat amplification protocol（TRAP). Results Eighteen of 19 samples of thyroid carcinoma, 1 of 15 samples adjacent to the cancer and 1 of 21 adenoma of the thyroid specimens showed positive telomerase activity, all 17 cases of nodular goiters and 18 samples of normal thyroid tissues exhibited negative telomerase activity, and the rate of positive telomerase activity of thyroid carcinomas was significantly higher than that of the other tissues (P＜0.0001). Conclusion The telomerase is an important qualitative marker of thyroid carcinoma and a useful index in differential diagnosis of thyroid lesions.
OBJECTIVE: To explore the SV40-mediated immortalization, the related factors and their roles in cell immortalization. METHODS: The original articles about cell immortalization and replicative senescence in recent decade were reviewed. RESULTS: Cell immortalization was a multifaceted phenomenon, it was involved in viral DNA integration, activation of telomerase, inactivation of growth suppressors, and so on, and their roles were closely related. CONCLUSION: The research on cell immortalization may be expected to provide important insights into a broad range of cellular biological phenomenon, and the immortalized cells can play important roles in the research of cell engineering and tissue engineering as standard cells.