Clonal Heterogeneity in Telomerase Activity and Telomere Length in Tumor-Derived Cell Lines

2008 ◽  
Vol 223 (4) ◽  
pp. 379-388
Author(s):  
Isabelle Savre-Train ◽  
Lauren S. Gollahon ◽  
Shawn E. Holt
Keyword(s):  
Telomere Length ◽  
Cell Lines ◽  
Telomerase Activity ◽  
Clonal Heterogeneity

Telomerase activity, mTert gene expression and the telomere length in mouse mesenchymal stem cells in the late period after γ- and γ,n-irradiation and in the tumors developed from these cells

2020 ◽  
Vol 66 (3) ◽  
pp. 265-273
Author(s):  
O.V. Vysotskaya ◽  
A.I. Glukhov ◽  
Yu.P. Semochkina ◽  
S.A. Gordeev ◽  
E.Yu. Moskaleva
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Telomere Length ◽  
Cell Lines ◽  
Telomerase Activity ◽  
Mouse Bone Marrow ◽  
Fibrosarcoma Cell

In proliferating normal and tumor cells, the telomere length (TL) is maintained by high telomerase activity (TA). In the absence of TA the TL maintenance involves a mechanism of alternative lengthening of telomeres (ALT). The aim of this study was to investigate the level of TA, the mTert expression and TL in cultured normal and transformed by γ- and γ,n-irradiation mesenchymal stem cells (MSCs) from mouse bone marrow, in sarcomas that developed after the transplantation of these cells into syngeneic mice, and in fibrosarcoma cell lines obtained from these tumors to find out the role of AT or ALT in maintaining TL in these cells. During prolonged cultivation of normal and transformed under the influence of γ- (1 Gy and 6 Gy) and γ,n-irradiation (0.05 Gy, 0.5 Gy, and 2 Gy) MSCs from mouse bone marrow, a decrease in TA was detected in irradiated cells. Even deeper decrease in TA was found in sarcomas developed after administration of transformed MSCs to syngeneic mice and in fibrosarcoma cell lines isolated from these tumors in which TA was either absent or was found to be at a very low level. TL in three of the four lines obtained was halved compared to the initial MSCs. With absent or low TA and reduced TL, the cells of all the obtained fibrosarcoma lines successfully proliferated without signs of a change in survival. The mechanism of telomere maintainance in fibrosarcoma cell lines in the absence of TA needs further investigation and it can be assumed that it is associated with the use of the ALT. The detected decrease or absence of TA in transformed under the action of irradiation MSCs with the preservation or even an increase in the telomerase gene expression may be associated with the formation of inactive splicing variants, and requires further study. The obtained lines of transformed MSCs and fibrosarcomas with TA and without the activity of this enzyme can be a useful model for studying the efficacy of TA and ALT inhibitors in vitro and in vivo.

Techniques in gerontology: Cell lines as standards for telomere length and telomerase activity assessment

2006 ◽  
Vol 41 (6) ◽  
pp. 648-651 ◽  
Author(s):  
Christine Fehrer ◽  
Regina Voglauer ◽  
Matthias Wieser ◽  
Gerald Pfister ◽  
Regina Brunauer ◽  
...  
Keyword(s):  
Telomere Length ◽  
Cell Lines ◽  
Telomerase Activity ◽  
Activity Assessment

Shortened telomere length and increased telomerase activity in hamster pancreatic duct adenocarcinomas and cell lines

1997 ◽  
Vol 18 (3) ◽  
pp. 153-159 ◽  
Author(s):  
Kunihiko Kobitsu ◽  
Masahiro Tsutsumi ◽  
Toshifumi Tsujiuchi ◽  
Fumio Suzuki ◽  
Akira Kido ◽  
...  
Keyword(s):  
Pancreatic Duct ◽  
Telomere Length ◽  
Cell Lines ◽  
Telomerase Activity

scholarly journals YY1 Promotes Telomerase Activity and Laryngeal Squamous Cell Carcinoma Progression Through Impairment of GAS5-Mediated p53 Stability

2021 ◽  
Vol 11 ◽  
Author(s):  
Xudong Wei ◽  
Fenglei Liu ◽  
Xuelian Jiang ◽  
Xiaoyan Xu ◽  
Tianhao Zhou ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Telomere Length ◽  
Cell Lines ◽  
Colony Formation ◽  
Laryngeal Squamous Cell Carcinoma ◽  
Telomerase Activity ◽  
P53 Stability

Yin Yang 1 (YY1) is a key transcription factor that exerts functional roles in the cell biological process of various cancers. The current study aimed to elucidate the role and mechanism of YY1 in laryngeal squamous cell carcinoma (LSCC). YY1 mRNA and protein expression in human LSCC cell lines was detected by RT-qPCR and Western blot analysis. An interaction of YY1, GAS5, and p53 protein stability was predicted and confirmed by bioinformatics, ChIP, Co-IP, RIP, and FISH assays. Following loss- and gain-function assays, LSCC cell proliferation, colony formation, cell cycle, telomere length and telomerase activity were evaluated by CCK-8 assay, colony formation assay, flow cytometry, and PCR-ELISA, respectively. Nude mice were xenografted with the tumor in vivo. LSCC cell lines presented with upregulated expression of YY1, downregulated GAS5 expression, and decreased p53 stability. YY1 inhibited the expression of GAS5, which in turn recruited p300 and bound to p53, thus stabilizing it. Moreover, YY1 could directly interact with p300 and suppressp53 stability, leading to enhancement of cell proliferation, telomere length and telomerase activity in vitro along with tumor growth in vivo. Collectively, YY1 can stimulate proliferation and telomerase activity of LSCC cells through suppression of GAS5-dependent p53 stabilization or by decreasing p53 stability via a direct interaction with p300, suggesting that YY1 presents a therapeutic target as a potential oncogene in LSCC development and progression.

Telomerase Inhibition, Telomere Shortening and Apoptotic Cell Death in Multiple Myeloma Cells Following Exposure to a Novel and Potent Telomerase Inhibitor (GRN163L), Targeting RNA component of Telomerase.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 638-638 ◽  
Author(s):  
Masood A. Shammas ◽  
Hemant Koley ◽  
Alexi Protopopov ◽  
Pierfrancesco Tassone ◽  
Paola Neri ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Telomere Length ◽  
Cell Lines ◽  
Apoptotic Cell ◽  
Annexin V ◽  
Telomerase Activity ◽  
Telomere Shortening ◽  
Myeloma Cells ◽  
Telomerase Inhibitor

Abstract Telomeres, the specialized nucleoprotein structures at the ends of chromo-somes, shorten at each DNA replication, and if unopposed leads to chromosomal erosion and cell death. Telomere shortening below a critical length is prevented by telomerase. We have previously observed elevated telomerase activity and shortened telomeres in multiple myeloma (MM), making the telomere maintenance mechanism an important target for therapy. Based on success with other non-specific telomerase inhibitors, in this study, we evaluated the effects of a thio-phosphoramidate oligonucleotide specifically targeting the RNA component of telomerase (GRN163L), with modifications to facilitate its delivery into human cells. Nuclear uptake of GRN163L without need for transfection enhancer at 24h was confirmed in >99% MM cells using fluorescein isothiocyanate-tagged GRN163L and confocal microscopy. Next we evaluated the effects of different concentrations and length of exposure of GRN163L on telomerase activity in diff MM cell lines (ARP and INA6). Whereas control oligonucleotide did not significantly affect telomerase activity, ≥ 80% loss of telomerase activity was observed in MM cell lines at day 3 at submicromolar concentrations of GRN163L. This inhibition of telomerase activity was associated with inhibition of myeloma cell growth and survival. Treatment of INA6 cells with GRN163L for three weeks induced 96±4% and 100% cell death at 0.5 and 1 μM concentrations, respectively, while ARP cells with higher telomerase activity and longer telomeres showed 67 ± 4% cell death at 5 weeks with 0.5 μM inhibitor and 82 ± 3% and 100% cell death at 4 and 5 weeks respectively with 2 μM concentration. The cell death was predominantly apoptotic, as determined by 51% annexin V-positive INA6 cells at two weeks and >80 % annexin V positive ARP cells at four weeks. The apoptotic cell death was associated with reduction in telomere length as analyzed using Telomere-FISH. While the control oligo treated ARP cells showed mean Telomere Fluorescence Intensity (TFI) on interphase chromosomes of 17.2 ± 1.5 (range 1.3–146.4), GRN163L treated cells showed reduction of mean TFI to 13.6 ± 0.46 (range 0.74 – 65.7). Although values above 100 were observed on 2 chromosomes in control oligo treated cells, GRN163L-treated cells had no chromosome with a TFI of more than 70.0. A similar reduction in telomere length was observed for INA6 cells. Subsequently, we were also able to increase cytotoxicity of DNA damaging agents in MM cells treated with GRN163L and shortened telomeres; providing a rationale for evaluation of combination therapies. These data demonstrate GRN163L as a potent and specific telomerase inhibitor able to disrupt telomere integrity and inducing apoptotic death of multiple myeloma cells. Evaluation of this agent in a SCIDhu model of myeloma is underway prior to its clinical evaluation.

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