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 does telomerase contribute to cancer?
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. In humans, the distribution of TL among different chromosome arms is heterogeneous.
Is telomerase activated in cancer cells?
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 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 , a biomarker of almost all advanced human cancers (Fig. 1).
Why is telomerase a potential target for cancer therapy?
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 .
Does telomerase prevent 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.
What is the role of telomerase?
Telomerase is a key enzyme for cell survival that prevents telomere shortening and the subsequent cellular senescence that is observed after many rounds of cell division. In contrast, inactivation of telomerase is observed in most cells of the adult liver.
How can telomerase be targeted as a cancer treatment?
Approaches to targeting telomerase include: (1) Immunotherapies—peptide or DNA vaccines supply immunogenic TERT epitopes that stimulate immune responses against telomerase-expressing cancer cells. Adoptive cell transfer therapies entail the infusion of telomerase-specific cytotoxic T cells.
Why do cancer cells have short 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 does telomerase do that would be important for both cancer cells and embryonic 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.
What is telomerase and why is it important?
The enzyme telomerase adds TTAGGG repeats onto mammalian telomeres, which prevents their shortening. … The activation of telomerase in malignant cancers seems to be an important step in tumorigenesis, whereby the cell gains the ability of indefinite proliferation to become immortal.