Notes: Regulating the Cell Cycle
What is cancer?
If we want to cure cancer…. We must understand what the causes are. That means understanding the cell cycle.
Cells divide at different rates, depending on the cell type Nerve and muscle cells usually stop dividing once developed Skin cells divide frequently as skin is being replaced constantly
When control of the cell cycle fails, cells begin to divide uncontrollably, resulting in masses and failure of the cells to perform their normal functions. This condition is called cancer. The study of cancer is called oncology.
What Controls Cell Division? Cell cycle regulators Cyclin (proteins) Internal regulators External regulators Tumor Suppressor Genes (oncogenes)
Checkpoints There are strict checkpoints in the cell cycle to ensure that each stage does not start before the last one has finished. Other checkpoints prevent cells dividing when their DNA is damaged - either allowing time to repair the damage or, if the DNA is too damaged, causing cell death (apoptosis).
Cancer = Uncontrolled cell growth Uncontrolled means it takes over the cell cycle! Causes can be environmental, genetic, or viruses
How is cancer treated? Drugs (chemotherapy) are used to target cells that are dividing Tumors can sometimes be removed via surgery Radiation can target an area Metastasis: When cancer cells move to a different part of the body.
Stem Cells Stem cells are unspecialized cells that have the potential to differentiate (to become any type of cell)
Stem cells can be found in: Human embryos Some adult cells Cord blood The use of stem cells is controversial. Why?
Potential Uses for Stem Cells Repair injuries of the brain and spinal cord Cure some diseases (diabetes) Replace organs (liver tissue, heart valves)