How cancer cells are able to avoid dying?

As an expert in the field of cellular biology, I can explain the mechanisms by which cancer cells manage to evade the normal process of cell death, which is a critical aspect of their uncontrolled proliferation. Cancer cells have developed several strategies to avoid dying, which are often a result of mutations in the genes that regulate cell cycle and cell death. Here are some of the key ways in which cancer cells avoid apoptosis: 1. Mutation of Tumor Suppressor Genes: These genes normally act as the "brakes" of the cell cycle, ensuring that cells do not divide uncontrollably. When these genes are mutated, they can no longer perform their regulatory function, allowing cells to divide without restraint. 2. Resistance to Pro-Apoptotic Signals: Cancer cells can develop resistance to signals that would normally trigger apoptosis. This can occur through mutations in the receptors for these signals or in the pathways that transmit the signal to the cell's death machinery. 3. **Overexpression of Anti-Apoptotic Proteins**: Cancer cells may produce excessive amounts of proteins that inhibit apoptosis. For example, the protein Bcl-2 is known to block apoptosis, and it is often overexpressed in cancer cells. 4. Altered Cell Signaling: Cancer cells can have altered signaling pathways that affect how the cell responds to its environment. This can lead to a situation where the cell does not receive or respond to signals that would normally lead to apoptosis. 5. Enhanced DNA Repair Mechanisms: Cancer cells may have enhanced mechanisms to repair the DNA damage that could lead to apoptosis. This allows them to survive and continue to divide despite the damage. 6. Immune Evasion: The immune system can recognize and destroy cells that are behaving abnormally. Cancer cells can develop ways to avoid detection or resist the actions of the immune system, thus escaping immune-mediated cell death. 7. Autophagy Inhibition: Autophagy is a process where cells can degrade and recycle their own components. While this can sometimes be a survival mechanism, cancer cells may inhibit autophagy to prevent the degradation of essential components, thus promoting their survival. 8. Angiogenesis: Cancer cells can stimulate the growth of new blood vessels (angiogenesis) to supply the tumor with nutrients and oxygen, which can help the cancer cells survive and grow.

Cancers can result from cells that do not die when they should. ... Professor Robert Weinberg discusses how cancer cells have to learn how to avoid the process of programmed cell death known as apoptosis carried out in normal cells. Transcript: Just as signals regulate cell growth and division, signals control cell death.