What makes telomerase a viable target for cancer therapies?
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 .
Is telomerase active in cancer cells?
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.
How does having a fully active telomerase contribute to cancer?
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.
Why is telomerase active in normal stem cells and most cancer cells?
Telomerase, a RNA-containing enzyme that synthesizes DNA onto the ends of chromosomes, helps to maintain the integrity of the genome in embryonic stem cells and in proliferating progenitor cells derived from quiescent normal stem cells.
How does telomerase enable cancer cells?
Cancer cells often avoid senescence or cell death by maintaining their telomeres despite repeated cell divisions. This is possible because the cancer cells activate an enzyme called telomerase, which adds genetic units onto the telomeres to prevent them from shortening to the point of causing senescence or cell death.
How could telomerase inhibitors be used to treat 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).
What kind of cancer does cadmium cause?
Cadmium is an established human and animal carcinogen. Most evidence is available for elevated risk for lung cancer after occupational exposure; however, associations between cadmium exposure and tumors at other locations including kidney, breast, and prostate may be relevant as well.
Are cancer cells immortal?
Cancer cells have been described as immortal because, unlike normal cells, they don’t age and die, but instead can continue to multiply without end.
Why do telomeres not shorten in cancer cells?
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.
Is telomerase good or bad?
Too much telomerase can help confer immortality onto cancer cells and actually increase the likelihood of cancer, whereas too little telomerase can also increase cancer by depleting the healthy regenerative potential of the body.
What is the role of telomerase in 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.
Do all cancer cells have telomerase?
Telomerase activity has been found in almost all types of human cancer, although not all. Most cancers that do not have active telomerase have found other ways to maintain the length of their telomeres.
What is the connection between telomerase activity 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.
What is the relationship between telomeres and cancer?
Since telomere shortening is strongly correlated with an increased risk of cancer during aging and chronic disease, the scientific literature suggests that the loss of telomere capping function contributes to the induction of chromosomal instability and cancer initiation process.
What is a hallmark of cancer cells?
The hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis.