In Vitro transformation

Question 1

What are the characteristics of virus transformed cells?

Answer 1

Loss of contact inhibition
Reach high saturation density and don’t arrest growth in G1/G0.
Grow in suspension
ARE Tumourigenic in immuno compromised mice.
Increased glycolysis, nutrient uptake, membrane fluidity.

Question 2

Give examples of transformed cells.

Answer 2

AEV carries truncated EGFR sequences –> constitutively active.

SSV -expresses p28sis - shares homology to PDGF.

Bladder carcinoma ha-Ras gene shares homology to v-Ha-Ras (viral oncogene).

Question 3

Why do suspended cells have a reduced growth rate?

Answer 3

Smaller SA than flat spread cells –> less access to GFs in medium as limited by diffusion.

Question 4

How frequently is telomerase deactivated in cancer cells? How is it reactivated?

Answer 4

80-90% cancers
Epigenetic regulation of promoter activity, gene locus amplification, regulatory factors (c-MYC).

(ALT pathway = recombination - also induces long telomeres but independent of telomerase).

Question 5

Describe stress and oncogene induced cell senescence.

Answer 5

Stress - p16 induction –> Rb activity maintained.

Oncogene - p53-p21 induction, p16 expression.

DNA damage - p53-p21 and/or p16-Rb
Replicative = telomere shortening and p
p53-p21 growth arrest.

Question 6

What are the early cellular responses to serum factors?

Answer 6

Ligand-receptor activation 
MAPK cascades
Ion fluxes
Metabolite uptake 
Protein synthesis 
Gene expression.

Question 7

What does minimal media contain?

Answer 7

13 essential AAs
8 vitamins
Inorganic salts and glucose.

Question 8

What is imetalstat?

Answer 8

Small molecule inhibitor of telomerase entering phase II clinical trials.
Chemically modified oligont - inhibits interaction between telomerase and DNA
More effective against myeloproliferative disorders compared to solid tumours.