Chemotherapy Immunotherapy
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The Normal Cell Cycle - ✔✔✔-The cell cycle refers to the ordered series of processes of
DNA replication and mitosis, or cell division
-Cell nucleus regulates these processes by gathering and processing complexes molecular
information
Interphase and Mitotic Phase - ✔✔✔Cell division produces two identical cells through these
two major phases
During interphase: - ✔✔✔Cell grows and DNA is replicated through the following three
steps:
1: First growth phase (G1 or first gap)
2: Synthesis phase (S phase)
3: Mitotic Phase (M phase)
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First Growth Phase (G1 or first gap) - ✔✔✔-cells increase in size
-reproduce RNA
-"quality assurance" test that the cell will be ready to synthesis DNA
-Length of time is variable, can be from hours to days
Synthesis Phase (S phase) - ✔✔✔-DNA replicates
-Results in the formation of identical pairs of DNA (chromatids)
-which are attached a t the centromere
-Lasts 2-10 hours
Mitotic Phase (M phase) - ✔✔✔-Replicated chromosomes are aligned, separated, and move
into 2 new, identical daughter cells
-Takes about 30-60 minutes
Major points of cell regulation are entry and exit from - ✔✔✔-G1 checkpoint
-S Phase
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-G2 checkpoint
-M phase
Restriction Point - ✔✔✔-The transition from the resting phase into an actively dividing
phase (G0-G1) is a point where cellular transformation can occur
-During this time, cells pass through a transition phase known as a restriction point
-Extracellular growth factors trigger reentry into G1, and GF are required to send the cells
past the restriction point, or the point of no return
G0 Phase (resting phase) - ✔✔✔-After mitosis, cells may enter back into the G1 phase or go
into a resting phase, known as G0
-Most cells in the human body reside in G0
Tumor suppressor genes - ✔✔✔-act like brakes in a car, slowing down or stopping cell
growth and division
-in the presence of malignancies, they bind to DNA with intention of repairing or activating
apoptosis
-for it to be turned on it must be expressed or "opened" in the DNA helix so that it can be
transcribed or copied
p53 - ✔✔✔-"sucidie gene"
-activates apoptosis when the cell is damaged beyond repair or too old to function
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-more than 50% of solid tumors, the gene is mutated and unable to perform its normal
function
Growth Signals - ✔✔✔-cancer cells are able to find their own growth signals making them
self-sufficient
Signal transduction - ✔✔✔-the communication or passage of a message telling the cell to do
a biologic process, such as make a protein, divide, or make new blood vessels
Signal transduction steps - ✔✔✔1. Messages usually sent from outside the cell where the
messenger (ligand) first binds to the cell receptor which extended through the cell membrane
2. These receptors ae called receptor tyrosine kinases
3. To send the message through the membrane, the receptor often has to join with another
recetor to become active and t autophophorylate
4. This is called dimerization and can be the following:
Dimerization - ✔✔✔1. Homodimerization: binding with the same type of receptor, such as
an epidermal GF receptor (EGFR) 1 receptor with another EGFR
2. Heterodimerization: binding with a different kind of receptor, such as EGFR1 binding with
EGFR2
Protein tyrosine kinases phosphorylates - ✔✔✔-turned on by giving up a phosphate molecule
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