Cell Cycle CANCER

Apoptosis is programmed cell death. – a normal feature of healthy organisms – caused by a cell’s production of self-destructive enzymes – occurs in development of infants – Cancer cells do not undergo apoptosis webbed fingers

Signals for cell division Internal – checkpoints regulated (turned “on” and “off” by proteins called cyclins. External – regulated by environmental factors outside of the cell

External factors Growth factors – Proteins released by some cells that stimulate other cells to divide density-dependent inhibition – crowded cells stop dividing anchorage dependence – to divide cells must be attached to a substrate

Cancer – uncontrolled cell division Tumors - uncontrolled growth -cell cycle has no control 2 TYPES Benign – noncancerous Malignant – cancer - metastasizes - spreads throughout the body - lethal

Metastasis – spread of cancer cells cancer cell bloodstream normal cell

Development of Cancer Cancer develops after 6 key mutations (“hits”) 1) unlimited growth turn on growth promoter genes 2) ignore checkpoints turn off tumor suppressor genes It’s like an out-of-control car with many systems failing!

3) escape apoptosis turn off suicide genes 4) immortality = unlimited divisions turn on chromosome maintenance genes 5) promotes blood vessel growth turn on blood vessel growth genes 6) overcome anchor & density dependence turn off touch-sensor gene

What causes these “hits”? Mutations in cells can be triggered by  UV radiation  chemical exposure  radiation exposure  heat  cigarette smoke  pollution  age  genetics