Telomere length and proliferation potential of hematopoietic stem cells.

Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
Journal of Cell Science (Impact Factor: 5.33). 02/1995; 108 ( Pt 1):1-6.
Source: PubMed

ABSTRACT Hematopoietic stem cells have typically been defined as pluripotent cells with self-renewal capacity. Recent studies have shown striking differences in the mean length of telomeric repeat sequences at the end of chromosomes from human hematopoietic cells at different stages of development. The most likely explanation for these observations is that hematopoietic stem cells, like all other somatic cells studied to date, lose telomeric DNA upon each cell division. In this review, limitations in the replicative potential of hematopoietic stem cells are discussed in the context of possible clinical use of such cells for transplantation and gene therapy.

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    ABSTRACT: Stem cells are the developmentally early forms of flexible cell types which can give rise to multiple cell types. Embryonic and adult stem cells are the two types of stem cells occurring in the mammalian system, which are responsible for giving rise to myriads of cell types during the development. Accordingly, harnessing the potential of stem cells is considered to have great significance for therapeutic purpose. Also, stem cells have certain features like unlimited proliferation potential, which they share closely, with the rogue cells of any mammalian system, which are cancer cells. In addition, there are stem cells, which give rise to cancer and are called cancer stem cells. In this review, we have addressed the developmental aspects of stem cells, cancer cells and cancer stem cells, their respective biological functions in maintaining an intricate balance to decide their respective contributions to the usefulness or harmfulness in the biological system.
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    ABSTRACT: Telomerase reverse transcriptase (TERT) is the protein component of telomerase and combined with an RNA molecule, telomerase RNA component, forms the telomerase enzyme responsible for telomere elongation. Telomerase is essential for maintaining telomere length from replicative attrition and thus contributes to the preservation of genome integrity. Although diverse mouse models have been developed and studied to prove the physiological roles of telomerase as a telomere- elongating enzyme, recent studies have revealed non-canonical TERT activities beyond telomeres. To gain insights into the physiological impact of extra-telomeric roles, this review revisits the strategies and phenotypes of telomerase mouse models in terms of the extra-telomeric functions of telomerase.
    Yonsei medical journal 01/2014; 55(1):1-8. · 0.77 Impact Factor
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    ABSTRACT: Telomerase plays a key role in carcinogenesis. It is activated in most immortal cell lines and human cancers, including cutaneous melanoma (CM). Increased cell proliferation and deregulation of the cell cycle occur in human cancers. Links between telomerase activity (TA), cell proliferation, cell death and expression of cell-cycle regulators have not been extensively elucidated in CM. In this study, we investigated TA, mitotic index (MI), apoptotic index (AI), Ki-67 and nuclear positivity of cyclins D1 and A (Ki-67+N/1,000, cyclin D1+N/1,000, cyclin A+N/1,000) in 42 primary cutaneous melanomas (PCMs). TA was detected in all cases and directly correlated with MI, Ki-67+N/1,000, cyclin D1+N/1,000 and cyclin A+N/1,000 (p < 0.001); it was not correlated with AI. When subdividing PCMs into radial and vertical growth phase melanomas (RGPMs, VGPMs), a correlation was maintained only with MI (p < 0.005) and cyclin D1+N/1,000 (p < 0.005). Although MI and Ki-67+N/1,000 were highly correlated with cyclin D1+N/1,000 and cyclin A+N/1,000 (p < 0.001) when considering all cases together, a high correlation was found in the RGPM and VGPM groups between cyclin A+N/1,000 and Ki-67+N/1,000 only (p < 0.001), thus suggesting that cyclin A is more closely correlated with cell proliferation than cyclin D1. Our results further support the association between TA, tumor cell proliferation and cyclin D1 and A expression in PCM, though it is possible that links between TA and proliferation, on the one hand, and TA and cyclin D1 expression, on the other, might occur following various pathways. Int. J. Cancer 88:411–416, 2000. © 2000 Wiley-Liss, Inc.
    International Journal of Cancer 01/2000; 88(3):411-416. · 6.20 Impact Factor


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