How is telomerase activated in cancer?

The regulation of telomerase activity in human cells plays a significant role in the development of cancer. Telomerase is tightly repressed in the vast majority of normal human somatic cells but becomes activated during cellular immortalization and in cancers.

What role do telomeres and telomerase play in cancer progression?

TL is critically important in normal cells, and telomere shortening can—in combination with other oncogenic changes—promote genome instability, potentially stimulating initiation of the early stages of cancer.

What is the relationship between telomeres and 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 might telomerase be used to combat cancer?

Due to telomerase inhibition, activity, or expression, these drugs might kill tumor cells by allowing telomeres to shrink or by provoking apoptosis. First of all, this process might have a chance to be cell-specific without serious side effects (Fig. 1).

Is telomerase active in cancer cells?

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).

Is telomerase active in somatic cells?

Telomerase activity is regulated during development and has a very low, almost undetectable activity in somatic (body) cells. Because these somatic cells do not regularly use telomerase, they age.

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].

Is it possible to use telomerase as a biomarker or a target for cancer therapy?

Telomerase activity may, therefore, be a useful biomarker for diagnosis of malignancies and a target for inactivation in chemotherapy or gene therapy.

Do telomeres and telomerase show promise in the fight against cancer?

Due to its high activity in the majority of cancers and low expression in somatic cells, telomerase and the telomere as a whole are very promising targets [2,10]. Continued studies on telomeres may provide promising avenues of research in the development of novel anticancer therapeutics.

Why is telomerase turned off in somatic cells?

Telomerase activity is absent in most normal human somatic cells because of the lack of expression of TERT; TERC is usually present. The absence of telomerase activity in most human somatic cells results in telomere shortening during aging.

What cells is telomerase active in?

Telomerase is found in fetal tissues, adult germ cells, and also tumor cells. Telomerase activity is regulated during development and has a very low, almost undetectable activity in somatic (body) cells.

Can telomerase cure cancer?

Although the inhibition of telomerase may strip some cancers of their immortality, cancers are still viable and largely unaffected by the loss of telomerase.

Does telomerase play a role in cancer progression?

Increased telomerase expression produces vulnerability of cancer cells, distinguishing them from normal cells in the body, although normal cells do also have some active telomerase. Recent studies also suggest that telomerase is implicated in tumor progression in unexpected ways.

What is the role of telomerase in HIV?

Unlike viral or retroviral reverse transcriptases, such as that of HIV-1, the cellular enzyme telomerase specializes in making the multiple short tandem repeats that are at the ends of chromosomes.

What are telomeres and why are they important?

Telomeres, repetitive (TTAGGG) DNA–protein complexes at the ends of chromosomes, are crucial for the survival of cancer cells. They are maintained by an enzyme called telomerase in the vast majority of tumors.

How do Dysfunctional telomeres trigger senescence?

Dysfunctional telomeres, arising by critical shortening of telomeres in normal somatic cells during progressive cell divisions, elicit DNA damage responses (DDRs) that trigger cellular senescence.