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Flashcards in cell cycle and cell death Deck (22)
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1
Q

why do hereditary cancers present at earlier ages?

A

already at the “initiation” phase

2
Q

what ways can activate pro to-oncogenes –> oncogenes? (3)

A

mutation
chromosomal translocation
amplification

3
Q

when do all oncogenes act?

A

before or during G1

4
Q

example of autocrine regulation of cell growth in T-cell leukemia

A

Over expression of interleukin-2 and interleukin-2 receptor leads to increased T-cell growth

5
Q

describe Her2-Neu

A

breast CA cells
val- –> glu in the transmem region leads to dimerization for stability and will activate receptor without ligand present

6
Q

describe EGF-ErbB

A

non-small cell lung CA

deletion leads to a constitutively active TKR

7
Q

discuss the “Ras” mutation

A

reduced GTPase activity leads to more raw-GTP (active)

8
Q

discuss B-Raf mutation

A

melanoma

B-Raf is MAP kinase Kinase, leads to increased activity

9
Q

discuss bcr-abl

A

CML

c-abl kinase fuses with bcr gene leading to increased phosphorylation

10
Q

discuss myc

A

neuroblastoma, b cell lymphoma

activates cyclin D and E2F

11
Q

what is the consequence of TGF-b receptor mutation/mutation in smads

A

decreased p15 and PAI-1

12
Q

what is p15 function?

A

inhibitor of cyclin d-CDK4,6 complexes

13
Q

what is PAI-1 function?

A

regulation of ECM proteins, role in mets

14
Q

what is the consequence of absent Rb?

A

E2F constantly on, does not require cyclinD-CDK4,6 complexes to activate

15
Q

what is the p21 CIP family?

A

inhibitor of kinase activity by binding cyclin D- CDK complexes, universal

16
Q

what is the INK4 family?

A

specific CDK inhibitors, p15 and p16

17
Q

describe p16

A

in INK4 family

cyclin D-CDK4 inhibitor

18
Q

what is p53?

A

check-point control protein that functions as a transcription factor

19
Q

what leads to increased p53 levels?

A

DNA damage

20
Q

what does p53 induce? (3)

A

expression of p21 CDK inhibitor
Bax
DNA repair enzymes

21
Q

what is BRCA-1?

A

scaffold protein that enhances activation of p53 and regulates Wee1 kinase and CDC25 phosphatase

22
Q

what type of enzyme is telomerase?

A

reverse transcriptase