How Do Cancer Cells Evade Growth Suppressors?
One of the hallmark capabilities of cancer cells is their ability to evade growth suppressors. This is often achieved through mutations in tumor suppressor genes like
p53 and
RB1. The loss of function in these genes removes critical checkpoints that normally prevent the cell cycle from proceeding when damage or mutations are detected.
What Role Does Apoptosis Play in Cancer?
Apoptosis is the process of programmed cell death that acts as a natural barrier to cancer. Cancer cells often acquire mutations that allow them to evade this process. For example, overexpression of
Bcl-2 proteins can inhibit apoptosis, allowing damaged cells to survive and proliferate.
How Do Cancer Cells Achieve Immortality?
Normal cells have a limited number of divisions due to the shortening of
telomeres. Cancer cells often activate
telomerase, an enzyme that extends telomeres, thereby granting them the ability to divide indefinitely. This is a critical step for the limitless replicative potential of cancer cells.
Why Is Angiogenesis Important for Tumor Growth?
To sustain rapid growth, tumors need a constant supply of nutrients and oxygen, which is achieved through
angiogenesis, the formation of new blood vessels. Cancer cells can secrete factors like
VEGF (Vascular Endothelial Growth Factor) to stimulate this process, ensuring their survival and expansion.
How Do Cancer Cells Metastasize?
Metastasis is the spread of cancer cells from the primary site to distant organs. This involves several steps: local invasion, intravasation into blood or lymphatic vessels, survival in the bloodstream, extravasation into new tissues, and eventual colonization. Each step requires specific adaptations, such as changes in cell adhesion molecules and the ability to degrade extracellular matrix components.
What Are Cancer Stem Cells?
Cancer stem cells (CSCs) are a subpopulation of cells within a tumor that possess the ability to self-renew and differentiate into various cell types. CSCs are thought to be responsible for tumor initiation, progression, and recurrence, making them a critical target for cancer therapies.
How Do Cancer Cells Alter Metabolism?
Cancer cells often exhibit altered metabolism to support their rapid growth and survival, a phenomenon known as the
Warburg effect. They preferentially use glycolysis for energy production, even in the presence of oxygen, which is less efficient but allows for the generation of additional biosynthetic precursors needed for cell proliferation.
