Lecture 11- Cell cycle regulation

Question 1

What are the hallmarks of cancer cells?

Answer 1

1. Metastises
2. Immortal (keep replicating)
3. Dont need signals to divide
4. Ignore apoptotic signals
5. They do angiogenesis (makes new blood vessels)
6. Grow autonomously

Question 2

WHat cintrols cell proliferation ?

Answer 2

Growth factors/mitogens and normal cells divde

Question 3

How can cancer cells proliferate ?

Answer 3

1. they produce GFs themselves
2. Stimulate neighbouring cells to release GFs
3. GF receptors are always active
4. activation of downstream signalling pathways of
   deregulation of GF receptor
5. Negative feedback loops are disrupted

Question 4

What happens in G1 in cell cycle?

Answer 4

Where cell communicates with enviroment, decides is made either divide or not divide (stay in G0 phase and not go past restriction point).
Restruction point is in G1
After restriction point you don’t need any signals
This happens 2-3 hours before S phase (DNA replication)

They get bigger in size and make proteins and organelles needed for normal functions of DNA synthesis.

Question 5

What is Flow Cytometry ?

Answer 5

Way to see what phase the cell is in does this by observing how much DNA is in the cells. Half the amount means the cell hasn’t been divided, still in G1.

Can use it to see the effect of a drug on cell division

Question 6

What are the advatages and disadvantages of Flow Cytometry ?

Answer 6

A - Very quantatitive and 1000s of cells can be analysed

D - Only do single cell analysis

Question 7

What is Immunofluorescence ?

Answer 7

Stain cell proteins that are in different phases of cell cycle.
BRDU - marks S phase
Cyclin B1 - G2/M phase
Histone 3 - marks G2/M phase

Question 8

What are the advantages and disadvantages of immunofluorescence ?

Answer 8

A- use in tissues,

D - Less quantitative and less cells are analysed

Question 9

What is Fucci system ?

Answer 9

Can be done on live cells immunofluorescence and flow symmetry cannot

It marks 2 dif proteins, CDT1 (high in G1 phase and low in S phase) and Hgem (high in S phase and low in G1)

CDT1 if present cells are red
Hgem if present cells are green

Question 10

What are the cells like in early and late G1 phase ?

Answer 10

If a cell is in early G1 it is more likely to differentiate into endoderm or mesoderm

If in late G1 will differentiate into neuroectoderm

Question 11

Why are cells on G1 phase more invasive?

Answer 11

Cells in G1 are more invasive, and more metastise because they secrete protease MT and MT1. They digest ECM making space and allowing cells to move.