Tutorial 2: DNA and Cell Division (Cancer)

Question 0

What are the six classical hallmarks of cancer cells?

Answer 0

1. resisting cell death
2. sustaining proliferative signalling
3. Evading growth suppressors
4. activating invasion and metastasis
5. enabling replicative immortality
6. inducing angiogenesis

Question 1

Describe what can go wrong as a result of uncontrolled cell cycling.

Answer 1

MUTATIONS: often caused by chemical/physiological agents and errors in DNA replication. Mutations can be inherited.
Normally, cells can repair some mistakes (DNA repair genes). If not repaired, changes in DNA sequence are made permanent by DNA replication. Normally, if DNA cannot be repaired, cells commit suicide (apoptosis).
Changes or errors in primary DNA sequence can be harmless or potentially lead to a loss of protein function.

Question 2

describe the different genes related to cancer.

Answer 2

Proto-oncogenes: code for proteins that promote cell division (drive cells from G1 to S). Mutations in proto-oncogenes –> oncogenes
Oncogenes: when switched on, stimulate the production of proteins that stimulate cell growth leading to cancer.
Tumor supressor genes: encode proteins that inhibit cell division (halt cell in G1–>G0). mutations in these genes switch them off and can cause cancer (eg p53).

Question 3

Describe the transition from benign cell division to cancer.

Answer 3

Uncontrolled division and disruption of normal cell organisation/tissue architecture –> Carcinoma
Metastasis: cells travel and establish colonies in other tissues through inactivation of controls that normally confine cells to one site.

Question 4

describe the types of cancer therapy.

Answer 4

Surgery: aims to physically removes cancer cells.
Radiation: causes irrepairable damage to DNA in cells, leading to apoptosis
Chemotherapy: drugs target rapidly dividing cells preferentially
novel therapies.