Apoptosis & Cancer

• Apoptosis is an integral process of the body

  
• Apoptosis is necessary for controlling total cell numbers in the body and for the removal of diseased or damaged cells

  
• Pathways of apoptosis initiation

  • Mitochondrial pathway
  • Death receptor pathway

  
• Mitochondrial pathway


  Recognises intracellular signals, mitochondria release cytochrome c into the cytosol. Cytochrome c binds with cytosolic proteins to form an apoptosome, which activates caspase enzymes, initiating apoptosis.
• Death receptor pathway


  Recognises extracellular molecules. When these molecules bind to a death receptor surface protein, caspase enzymes are activated, initiating apoptosis.

  
• Stages in Apoptosis


  1. Activation of caspases

  2. Digestion of cell contents

  3. Cell shrinks

  4. Membrane blebbing and breakage

  
• A decrease in the rate of apoptosis can cause the accumulation of cells, resulting in diseases such as cancer

  
• Apoptosis


  The natural and controlled death of cells within our body

  
• Apoptosis plays an important role in our development and day-to-day lives, as well as to prevent disease/harm to the organism

  
• Benign tumours


  • Relatively slow-growing masses of cells
  • Generally enclosed within a capsule
• Malignant tumours


  • Can invade nearby tissues
  • Can enter the bloodstream or lymphatic system
  • Considered cancerous
• When the rate of apoptosis decreases too much, cell growth can increase exponentially, resulting in the formation of tumours
• Characteristics of tumours/cancer cells

  • Self-sufficiency
  • Antigrowth deactivation
  • Increased survival
  • Blood supply formation
  • Tissue invasion and Metastasis
• Self-sufficiency in tumour cells

  Can replicate without chemical growth signals
• Antigrowth deactivation in tumour cells

  Mechanisms to prevent cell replication are disabled
• Increased survival in tumour cells

  Apoptosis no longer functions correctly<|>Capable of replicative immortality
• Blood supply formation in tumour cells

  Can form new blood vessels to maintain nutrient and oxygen supply
• Tissue invasion and Metastasis

  Capability of malignant cells to invade nearby tissues and migrate to other parts of the body