How are telomeres and cancer cells related?

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 is the relationship between telomeres telomerase aging and cancer?

Telomeres affect how our cells age. 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.

How is cellular senescence related to cancer?

Senescence is a double-edged sword that can function in opposite directions. It is a potential mechanism for a cell to avoid malignant transformation. However, senescence can also promote cancer development by altering the cellular microenvironment through a senescence-associated secretory phenotype (SASP).

How is cancer related to the size of telomeres?

The length of the ‘caps’ of DNA that protect the tips of chromosomes may predict cancer risk and be a potential target for future therapeutics. Longer-than-expected telomeres — which are composed of repeated sequences of DNA and are shortened every time a cell divides — are associated with an increased cancer risk.

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.

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).

What are telomeres and telomerase and how are they involved in determining longevity?

Telomeres are known to be one of the major determinants of aging. It helps to maintain telomere length by adding telomeric repeats “TTAGGG” to ends of the chromosome during DNA replication. Lifestyle plays an important factor in determining telomere length and telomerase activity.

Do telomeres prevent cancer?

Do cancer cells have senescence?

Senescence is generally regarded as a tumour suppressive process, both by preventing cancer cell proliferation and suppressing malignant progression from pre-malignant to malignant disease.

How does cellular senescence relate to the aging process?

Cellular senescence refers to a state of stable cell cycle arrest in which proliferating cells become resistant to growth-promoting stimuli, typically in response to DNA damage. Aging is a progressive decline with time whereas senescence occurs throughout the lifespan, including during embryogenesis.

Do all cancer cells have telomerase?

Cancer cells are characterized by high telomerase activity, which enables cells to divide indefinitely. Telomerase is active in 85–95\% of cancers (3,4). The exception is cancer cells possessing an active Alternative Lengthening of Telomeres (ALT) pathway.

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].

What is the relationship between telomeres and telomerase and cancer?

There is mounting evidence for the existence of an important relationship between telomeres and telomerase and cellular aging and cancer. Normal human cells progressively lose telomeres with each cell division until a few short telomeres become uncapped leading to a growth arrest known as replicative aging.

Is there telomere attrition in pre-cancer cells?

While there is substantial correlative evidence that there is telomere attrition in pre-cancerous tissues ( 13 – 16 , 22 – 26 , 29 – 31 , 34 – 40 ), the direct evidence that most pre-cancerous cells senesce, and that senescence is a potent tumor suppressor pathway, remains elusive.

What causes telomere dysfunction and senescence?

In addition to progressive telomere shortening (leading to replicative senescence), telomere dysfunction can be initiated by a change of state (‘uncapping’) that leads to a rapid induction of growth arrest that has also been termed senescence ( 10 , 117 – 133 ).

Can telomerase inhibitors drive cancer cells into apoptosis?

A rare cell that escapes crisis almost universally does so by reactivating telomerase and this cell can now become a cancer cell with limitless potential to divide. Almost all cancer cells have short telomeres and thus inhibitors of telomerase should drive such cancer cells into apoptotic cell death. Go to: 2. Telomeres and telomerase