lecture 11- the cell cycle and cancer 1 Flashcards
(27 cards)
what are the 6 hallmarks of cancer cells
grow autonomously
disregard cytostatic signals
ignore apoptotic signals
stimulate growth of new blood vessels
invade and metastasise
become immortal
describe cell proliferation control in normal cells
only grow when stimulated by growth factors
what are growth factors
small proteins released by certain cells which allow growth of other cells
aka. mitogens
describe cell proliferation in ESCs
can generate their own signals
are only example of wt cells able to generate a benign tumour when injected into adult
describe cell proliferation in cancer cells
occurs in faster and deregulated way
dont need growth factors
what are the 4 ways normal cell proliferation can be disrupted in cancer
1) produce their own GFs/ send signals to surrounding cells to release GFs
2) elevate receptor levels/ mutate receptors so they are always active
3) relay molecules always active
4)disruption of -ve feedback mechanisms
what is the R point of the cell cycle and when does it occur
window to decide between growth or quiescence (G0)
occurs from onset of G1 to 2 hrs before G1->S transition
how has the precise location of the R point been shown experimentally
Serum + Gfs removed before final hr of G1 = cells fails to proceed
Serum + Gfs removed in final hr of G1= cells proceed to S/G2/M
disruption of which stage of the cell cycle is most common in cancer tissues
R point
What does flow cytometry do
analyse DNA content by treating cells with DNA dye
in flow cytometry, what levels of dye would you expect in the different stages
least in G1
varied amount in S
most in G2 and M
why do non dividing cells have a smaller peak of G2/M cells
as less cells are in that stage
what is the main negative of flow cytometry
cells have to be the same type so cant study tissues
what is immunofluorescence used for in studying the cell cycle
stain the proteins specifically expressed in different phases of the cell cycle
what are the different proteins stained for the different cell cycle stages
BrdU = S phase
Cyclin B = G2/M
Histone H3 = M
How is BrdU able to be identified in S phase
it replaces T in DNA synthesis
what is the purpose of DAPI staining in immunofluorescence
binds all cells to show the DNA
what are the pros and cons of immunofluorescence
pro = can bind tissues
con= cells have to be fixed
What is FUCCI
different levels of fluorescent colour regulated by ubiquitin-dependant degregation
what are the 2 proteins involved in FUCCI
hCDT1 = red = peaks in G1 and decreases in S
hGem = green = peaks in S/G2 and decreases in M and G1
how has FUCCI been used in transgenic mice
used to study cell dynamics in the brain
cross hCDT1 mouse with hGem mouse then view cornonal sections
How can you use FUCCI to investigate the different cell fates or different stages of the cell cycle
use FACS to sort into the different cell cycle stages
Early G1= no fluo
Late G1= red
G1/S = orange
S/G2/M = green
then induce differentiation in these seperate groups
what are the results from using FACS to see how likely cels are to divide
early G1 = differentiate into endoderm/mesoderm
late G1 = differentiate into neuroectoderm
what is the main pro of using FUCCI
dont have to fix cells
