How does telomere relate to cancer?

It is believed that cancer occurs because a genetic mutation can trigger the production of an enzyme, known as telomerase, which prevents telomeres from shortening. While every cell in the body has the genetic coding to produce telomerase, only certain cells actually need it.

How do telomeres protect against cancer?

“The DNA in telomeres shortens when cells divide, eventually halting cell division when the telomere reserve is depleted.” New results from de Lange’s lab provide the first evidence that telomere shortening helps prevent cancer in humans, likely because of its power to curtail cell division.

How do cancer cells maintain their telomeres?

Telomeres, the protective structures of chromosome ends are gradually shortened by each cell division, eventually leading to senescence or apoptosis. Cancer cells maintain the telomere length for unlimited growth by telomerase reactivation or a recombination-based mechanism.

What are the roles of telomere and telomerase in cancer?

Equally important, cancer cells have evolved the ability to overcome senescence [6,7] by using mechanisms capable of maintaining telomere lengths (such as expressing telomerase), which enables cancer cells to divide indefinitely [7], a biomarker of almost all advanced human cancers (Fig. 1).

Why do cancer cells turn on telomerase?

It is turned on when making sperm and eggs and in some very early stages of life – in cells that will have to divide a lot. And it is turned on when cells become cancerous. Cancer cells may reactivate telomerase by changing the DNA around one of the genes that makes telomerase, called TERT.

Do cancer cells have telomeres?

Telomerase activity is closely related to the life stages of the body. The enzyme is active during embryonic development. Cancer cells are characterized by high telomerase activity, which enables cells to divide indefinitely. Telomerase is active in 85–95\% of cancers (3,4).

Why is telomerase an active target in cancer research?

Telomerase is an attractive target antigen for cancer immunotherapy because it is expressed almost universally in human cancers and is functionally required to sustain malignant tumor long-term growth [87].

Why do short telomeres cause cancer?

Once they lose a certain number of bases and become too short, the cell can no longer divide and be replicated. This inactivity or senescence leads to cell death (apoptosis) and the shortening of telomeres is associated with aging, cancer and an increased likelihood of death.

What are telomeres Why are they important?

Telomeres, the specific DNA–protein structures found at both ends of each chromosome, protect genome from nucleolytic degradation, unnecessary recombination, repair, and interchromosomal fusion. Telomeres therefore play a vital role in preserving the information in our genome.

Why are telomerase activity high in cancer cells?

Some of the cells avoid crisis and activate the telomerase gene, telomerase reverse transcriptase (TERT), which codes for telomerase, the enzyme responsible for the synthesis of telomere. Telomerase activity allows the cancer cell to have unlimited replication.

How do cancer cells turn on telomerase?

And it is turned on when cells become cancerous. Cancer cells may reactivate telomerase by changing the DNA around one of the genes that makes telomerase, called TERT. Barthel is particularly focused on determining how chemical changes to the TERT DNA allow telomerase to be turned on again.

Why do we need telomeres?

To prevent the loss of genes as chromosome ends wear down, the tips of eukaryotic chromosomes have specialized DNA “caps” called telomeres. Telomeres need to be protected from a cell’s DNA repair systems because they have single-stranded overhangs, which “look like” damaged DNA.

Why is telomere length important in cancer cells?

Telomeres maintain genomic integrity in normal cells, and their progressive shortening during successive cell divisions induces chromosomal instability. In the large majority of cancer cells, telomere length is maintained by telomerase. Thus, telomere length and telomerase activity are crucial for cancer initiation and the survival of tumors.

What happens when telomeres and telomerase are activated?

Telomeres and telomerase in normal and cancer stem cells. When telomerase is upregulated or reactivated in cells escaping crisis many outcomes could be predicted. For example, cells may not express enough telomerase and these cells would not be able to divide long-term to become robust malignant cancer cells.

Is telomerase a cancer-promoting agent?

In the context of cancer cells, particularly those that are well on the way to a malignant state, telomerase has cancer-promoting properties. It is in that latter context that we are interested in intervening in telomerase action.

What is the role of telomerase and Alt in cancer?

Telomere maintenance has been extensively studied, and our understanding of the role of telomerase and ALT in cancer has improved remarkably in recent years. It is becoming clear how cancer cells regulate different molecular events involved in telomere maintenance to expand their proliferative capacity.