Changes of telomerase activity during differentiation of human mesenchymal stem cells into adipocytes / 第二军医大学学报

Objective: To study the telomerase activity changes during the differentiation of human mesenchymal stem cells (MSCs) into adipocytes and the related mechanism. Methods: Human MSCs were isolated from human bone marrow by plastic adhesion and were characterized by immune phenotyping. The multilineage differentiation potential of MSCs was confirmed by inducing MSCs to differentiate into osteoblasts and neuron-like cells by corresponding agents. Telomeric repeat amplification protocol (TRAP) assay was performed to examine telomerase activity in MSCs during adipogenic differentiation of MSCs; Western blotting analysis was used to examine the protein expression levels of hTERT, TRF1, and Tankyrase 1. Results: TRAP showed that telomerase was negative in MSCs, but greatly up-regulated during the adipogenic differentiation process, peaked on the 7th day after adipogenic differentiation of MSCs(P<0.05), and then decreased thereafter. Western blotting analysis showed slight hTERT expression in MSCs, and the expression of hTERT and Tankyrase 1 increased during the adipogenic differentiation process, peaked on the 7 th day, and gradually decreased thereafter. The expression of TRF1 remained unchanged. Conclusion: Telomerase is weakly expressed in MSCs; the expression is increased during the adipogenic differentiation process of MSCs and then gradually decreases; and Tankyrase 1 may play an important role during the process.

Expression of human telomere repeat binding factor 1 (TRF1) in acute leukemia cells and its correlation with telomerase activities / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To study the expression of human telomere repeat binding factor 1 (TRF1) to investigate the correlation of telomerase activity with acute leukemia.</p><p><b>METHODS</b>Leukemic cells were collected from 30 cases of acute leukemia. Realtime quantitative PCR with fluorescence probe hybridization was used to measure expression of TRF1 and hTERT mRNA in leukemic cells.</p><p><b>RESULTS</b>TRF1 mRNA expression was 0.0126 (0.0127-0.0546) in acute non-lymphocytic leukemia (ANLL), which was lower than that in normal mononuclear cells [0.0457 (0.00839-0.262), P<0.001], but its expression in acute lymphoblastic leukemia (ALL) cells [0.0745 (1.92 x 10(-6)-0.193)] had no significant difference compared with that in normal mononuclear cells. TRF1 expression in ANLL cells was significantly lower than that in ALL cells (P=0.001). The expressions of TRF1 mRNA in AL cells and normal mononuclear cells had no significant correlation with expression of hTERT mRNA (r=-0.173, P=0.207).</p><p><b>CONCLUSION</b>The expression of TRF1 is lower in ANLL cells, which indicates TRF1 may have some effect on telomerase activity by regulating telomere length in ANLL cells.</p>

Expression of telomere repeat binding factor 1 (TRF1) protein in kidney cancer / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the expression levels of telomere repeat binding factor 1(TRF1) protein in normal kidney tissue and kidney cancer.</p><p><b>METHODS</b>Specimens of kidney cancer and pericancerous tissues were collected from 32 cases of renal carcinoma. A quantitative Western blotting technique was developed using TRF1 monoclonal antibody to determine the expression level of TRF1 protein in total protein extracts from tissue specimens.</p><p><b>RESULTS</b>The expression level of TRF1 protein was higher in normal kidney tissues (3.611 +/-1.922 microg/microl) than that of cancer tissues (2.428 +/-1.352 microg/microl) (t=5.776, P<0.01).</p><p><b>CONCLUSION</b>The expression level of TRF1 protein is significantly reduced in kidney cancer and the level is negatively correlated with malignant degree of the cancer.</p>