Cancer+Cell+Telomeres

Length of Cancer Cell Telomeres:
The lengths of telomeres of cancer cells have been found to be significantly shorter than those of normal somatic cells [1] [3] [4] [5]. When a normal cell reaches senescence, its telomere is short enough that the cell receives a message to cease dividing [2] [4]. Cancer cells do not receive this message [2] [3] [4]. Instead, when the point is reached that the telomere becomes too short it produces telomerase to extend its telomere for another division [3] [4]. This production of telomerase is not such that the telomere is extended to a greater length, but rather maintains the length the telomere already has [3] [4]. This means the telomere remains at a critically short length, and by the constant production of telomerase maintains this length [1] [3] [4] [5]. There have been several investigations which examine the lengths of telomeres of various cell types. For example, a report by Wai (2004) discusses the length of telomeres of normal somatic cells across varying ages, and shows that telomeres of younger cells are considerably longer than those of older cells, consistent with cell aging [4]. The results of Wai's investigation are shown in Figure 1 below. One investigation of particular interest is one conducted by Dahse, Fiedler and Ernst (1997), which discusses the length of telomeres of a variety of cancer cell types [2]. The results of this investigation suggest a possible link between the length of a cancer cell telomere and the severity of the disease [2]. Both these investigations imply that it may be possible to identify a cancer cell based on its telomere length, and distinguish it from normal somatic cell types [2] [4].

Figure 1: Cell types and respective telomere lengths (Picture obtained from Wai, 2004) By Ashlea Norton //Last edited 11/11/2011//

References:
 [1] Aubert, G. & Landsdorp, P.M. 2008, "Telomeres and Aging", //Physiological Reviews,// vol. 88, no. 2, pp. 557-579.

[2] Dahse, R., Fiedler, W. & Ernst, G. 1997, "Telomeres and Telomerase: Biological and Clinical Importance", // Clinical Chemistry, // vol. 43, no. 5, pp. 708-714.

[3] Greider, C.W. & Blackburn, E.H. 1996, "Telomeres, Telomerase and Cancer", // Scientific American, // vol. 96, no. 2, pp. 92.

 [4] Wai, L.K. 2004, "Telomeres, Telomerase and Tumorigenesis - A Review", //Medscape General Medicine,// vol. 6, no. 3, pp. 19.

 [5] Zvereva, M.I., Shcherbakova, D.M. & Dontsova, O.A. 2010, "Telomerase: Structure, Functions, and Activity Regulation", //Biochemistry (Moscow),// vol. 75, no. 13, pp. 1563-1583.