4 - Cell Cycle Checkpoints

Question 1

Loss of the cell cycle checkpoint control leads to?

Answer 1

Gathering mutations in advanced tumours

Question 2

Which enzyme is the rate limiting enzyme in G2 > M ?

Answer 2

Cdc 25

Question 3

What is Cdc 25 inhibited by?

Answer 3

Insufficient cell growth, stall replication, DNA damage

Question 4

Cancer arises through loss of checkpoints. Which ones?

Answer 4

Loss of restriction point, continualy proliferating cells; loss of DNA damage checkpoints, accumulation of DNA damage; loss of replicative stress checkpoint, mutations & breakage of chromosomes; loss of spindle assembly checkpoint, segregation & aneuploidy

Question 5

Traditional cancer treatments target?

Answer 5

All dividing cells, as the majority of adult cells are not dividing. Not suitable for childhood cancer

Question 6

Give examples of traditional cancer treatments?

Answer 6

Alkylating agents which cause excessive DNA damage to aim to stimulate cell death. Microtubule inhibitors depolymerise the spindle, and stimulate the spindle assembly checkpoint.

Question 7

Why do side effects occur in cancer treatments targeting dividing cells?

Answer 7

Because some cells still divide

Question 8

Which adult cells still divide?

Answer 8

Gut epithelia, immune cells, erythrocyte precursors, follicle cells

Question 9

Give examples of side effects from traditional cancer treatments that target dividing cells.

Answer 9

Gut epithelial cell death gives nausea and vomiting; immune cell death gives immune suppression; erythrocyte cell death gives anaemia; follicle cell death gives hair loss.