Objective To investigate the variety of telomerase activity in the course of liver cancer development, and the possibility of using telomerase as a marker of HCC. Methods Human liver specimens, comprising 22 HCC and adjacent peritumoral tissues, 12 liver cirrhosistissues, 6 nodulat regenerative hyperplasia (NRH) tissues and 10 normal liver tissues, were examined for telomerase activity by TRAP assay based on PCR. Results Twenty of 22 HCC and 14 of 22 adjacent tissue specimens were positive for telomerase activity with a positive rate of 90.9% and 63.6% respectively. Ten of 12 liver cirrhosis tissues were positive with a positive rate of 83.3%. 5 of 6 NRH were positive with a positive rate of 83.3%. Telomerase activity was negative in 10 normal liver tissues. Conclusion Telomerase may occur in the progress of hepatocarcinogenesis. Telomerase can be used as a tumor marker of HCC.
【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 elongate the proliferation life-span of human umbilicus vein endothelial cell (HUVEC). METHODS: We synthesized the human telomerase reverse transcriptase mRNA (hTERT mRNA) by in vitro transcription, then transferred the hTERT mRNA into HUVEC in quicent stage by lipofect introduction. RESULTS: Telomerase expressed transiently in HUVEC, and the cell life-span was elongated for 7 population doublings. CONCLUSION: Telomerase can be reconstructed controllably and transiently in HUVEC by hTERT mRNA introduction, this method has the potential to be used to elongate the lifespan of cells cultured in vitro.
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.
OBJECTIVE: To analysis the proliferation properties and telomerase activity of human embryonic tendon cells transformed by ptsA58H plasmid cultured in vitro continuously. METHODS: The 40th, 70th, and 75th passages of transformed human embryonic tendon cells (THETC) were adopted. The collagen secretion of THETC was detected by immunohistochemical methods, the growth curve of different passages of THETC was compared, and chromosome karyotype was analyzed. Total RNA of THETC were extracted to detect human telomerase reverse transcriptase (hTERT) mRNA expression by RT-PCR technique. RESULTS: When THETC were subcultured to 70 passages, the morphological characteristics of cells changed and began replicative senescence. THETC still could secret type I collagen normally. The chromosome of THETC was heteroploid (2n = 94). There were no hTERT mRNA expression. CONCLUSION: SV40 transfection can not make human embryonic tendon cells immortalization, on the other hand, human embryonic tendon cells transformed by ptsA58H plasmid has no tendency of malignant transformation.
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.
ObjectiveTo build a lentiviral expression vector regulated by two targets 5 copies of HREs and hTERTp, express the target gene CDX2, and to test the activity of hTERT promoter by using LoVo cells for transfection. MethodsAfter the primer sets were designed, the hTERT promoter was cloned by PCR amplification from the genome of colon cancer. The CEA promoter was removed from the original vector pLEGFP-5HRE-CEAp by double digestion and PCR method, and then the hTERTp was introduced into the vector to construct the recombinant plasmid pLEGFP-5HRE-hTERTp. 5HRE-hTERTp was obtained by PCR, while the CMV promoter was removed from the original vector pLVX-EGFP-3FLAG by double digestion and PCR method, and then the 5HRE-hTERTp was introduced into the vector to construct the recombinant plasmid pLVX-5HRE-hTERTp-EGFP-3FLAG. The CDX2 was cloned by PCR amplification from GV230-CDX2-EGFP, and the EGFP was removed from the vector pLVX-5HRE-hTERTp-EGFP-3FLAG by double digestion, and then the CDX2 was introduced into the vector to construct the recombinant plasmid pLVX-5HRE-hTERTp-CDX2-3FLAG. LoVo cells ex vivo was transiently transfected by pLVX-5HRE-hTERTp-EGFP-3FLAG to evaluate the activity of hTERTp by detecting the expression of green fluorescence protein EGFP. ResultsPCR and sequencing analyzing showed that pLEGFP-5HRE-hTERTp, pLVX-5HRE-hTERTp-EGFP-3FLAG, and pLVX-5HRE-hTERTp-CDX2-3FLAG were sequenced correctly and the same as our designed. pLVX-5HRE-hTERTp-EGFP-3FLAG was successfully transfected into LoVo cells ex vivo and expressed green fluorescence protein EGFP, which showed that hTERTp was activated and promoted the expression of downstream gene. ConclusionThe lentiviral expression vector, pLVX-5HREhTERTp-EGFP-3FLAG and pLVX-5HRE-hTERTp-CDX2-3FLAG are successfully constructed, which lays the foundation of further research. But the function of dual-target regulation needs further proof.
Objective To review the research process of telomerase reverse transcriptase (TERT) in the restoration of neurological diseases. Methods The related l iterature on TERT in the restoration of neurological diseases was extensively reviewed and comprehensively analyzed. Results TERT was the significant component of telomerase and the critical regulator of telomerase activity. It played an important role in the pathomechanism of neurological diseases including tumors,neurodevelopmental deficits, and nerve injury. TERT was becoming a research focus in the reparative therapy of neurological diseases. Conclusion TERT has manifested its great academic significance and appl ication prospects in the reparative therapy of neurological diseases, which deserves a further investigation.
OBJECTIVE: To construct a plasmid which has a reporter gene for exploring the role of human telomerase reverse transcriptase(hTRT) in in-vitro cell cultivation. METHODS: hTRT was cut by restricted enzyme from plasmid pGRN145 and inserted to plasmid pEGFP-C1 (enhanced green fluorescent protein). RESULTS: Restricted enzyme analysis and DNA sequencing showed that the sequence of the pEGFP -hTRT transgenic plasmid was correct. CONCLUSION: The recombinant vector pEGFP-hTRT has been successfully constructed, and it can be used as a transgenic plasmid in generating immortalized cell lines.
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.