Angiogenesis

Definition

Angiogenesis is the biological process through which new blood vessels form from existing ones. This process is crucial for growth and development, but it becomes particularly significant in the context of cancer, as tumors require a blood supply to grow and spread. When angiogenesis is activated by certain signals, it can contribute to the progression of cancer by enhancing nutrient and oxygen delivery to tumor cells.

5 Must Know Facts For Your Next Test

1. Angiogenesis is a normal physiological process that occurs during growth, wound healing, and reproduction.
2. In cancer, tumor cells release signals that promote angiogenesis, allowing tumors to grow beyond a certain size by ensuring adequate blood supply.
3. The balance between pro-angiogenic and anti-angiogenic factors is critical; an imbalance can lead to either excessive angiogenesis or insufficient blood supply.
4. Inhibiting angiogenesis has become a target for cancer therapies, as blocking the blood supply can restrict tumor growth and metastasis.
5. Angiogenesis is often assessed as a marker for tumor aggressiveness; higher levels of angiogenesis can indicate a worse prognosis.

Review Questions

• How does angiogenesis contribute to tumor growth and survival?
  • Angiogenesis supports tumor growth by supplying essential nutrients and oxygen through newly formed blood vessels. As tumors grow, they require more resources, which existing vessels alone cannot provide. Therefore, tumor cells secrete pro-angiogenic factors like VEGF to stimulate the formation of new blood vessels. This increased blood supply not only aids in tumor survival but also facilitates the spread of cancer cells into surrounding tissues.
• Discuss the mechanisms by which tumors can manipulate the angiogenic process to their advantage.
  • Tumors can manipulate the angiogenic process by overexpressing pro-angiogenic factors like VEGF while downregulating anti-angiogenic factors. This creates a favorable environment for blood vessel formation. Additionally, tumors may secrete enzymes that degrade the extracellular matrix, allowing endothelial cells to migrate and form new vessels. By hijacking normal angiogenic pathways, tumors effectively ensure their own growth and access to essential resources.
• Evaluate the potential benefits and challenges of targeting angiogenesis in cancer therapy.
  • Targeting angiogenesis in cancer therapy presents significant benefits, such as reducing tumor growth and limiting metastasis by cutting off its blood supply. Anti-angiogenic drugs have shown promise in various cancers, improving patient outcomes. However, challenges include the potential for resistance development, as tumors may adapt by utilizing alternative pathways for blood supply. Additionally, systemic side effects can occur due to the disruption of normal vascular processes, complicating treatment strategies.

Related terms

Vascular Endothelial Growth Factor (VEGF): A key signaling protein that stimulates the formation of blood vessels and plays a critical role in angiogenesis, especially in tumors.

Tumor Microenvironment: The surrounding environment of a tumor, which includes various cell types, blood vessels, and signaling molecules that influence tumor growth and metastasis.

Metastasis: The spread of cancer cells from the primary tumor to other parts of the body, often facilitated by the formation of new blood vessels through angiogenesis.