The linear ends of chromosome are protected by specialized ribonucleoprotein (RNP) termed as telomere. These specialized terminal elements with tandem repeated sequence are the protective cap that alleviate end replication problem and cell senescence. The tel
The linear ends of chromosome are protected by specialized ribonucleoprotein (RNP) termed as telomere. These specialized terminal elements with tandem repeated sequence are the protective cap that alleviate end replication problem and cell senescence. The telomere length maintenance is essential to avoid cell death and apoptosis. Telomere shortening has been related to chronic stress due to several factors, which include not only psychological stress but also diseases such as cardiovascular diseases and cancer. Telomerase enzyme which maintains telomere length is the major factor responsible for evading cell death. Telomere length maintenance and telomerase expression put together are the prerequisite for immortality, an essential character for cancer cells. Understanding the mechanism of telomere and telomerase functions paves way for eradicating the diseases such as cancer.
- telomere length
- tumor progression
- tumor immortality
Telomeres are specialized DNA structures consisting of tandem arrays of hexa-nucleotide (TTAGGG) DNA sequences that cap the end of chromosomes. These structures residing near the ends of chromosomes play a very vital role in maintaining the integrity of the whole genome and prevent the loss of genetic material. As a consequence of cell division, short stretches of DNA will be lost from telomeric region and eventually lead to cellular senescence and death. There are a lot of evidences to suggest that telomere length is a better biomarker for overall health status, compared to the currently used biomarkers for the same. Few of the phenomena regarding the telomere length are unanswered till now. Till date it is unclear about the mechanistic correlation between telomere size and life span of various species. To prevent senescence of cell, the preservation of telomere length is essential, which is maintained by telomerase enzyme. Telomerase is a reverse transcriptase enzyme which has recently emerged as an attractive target for cancer as it is a crucial factor required for the tumor immortalization of a subset of cells, including cancer stem cells. Studies have proved that 80–85% of the tumor cells express telomerase whereas somatic cells lack the expression of telomerase. The important paradox is that telomerase-negative normal cells have lengthier telomeres than telomerase-positive cancer cells. Thus difference in telomere length and cell kinetics between normal and cancerous cells shows that targeting telomerase is a more effective way to target cancer cells. Owing to the significant role of telomere and telomerase in tumor immortalization understanding their amassed influence on cancer is crucial for cancer therapy. In thi