Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology Of Cancer > Growth Factors And Receptors > Flashcards

Growth Factors And Receptors Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the three types of extracellular signals? Define each one

A

Endocrine - transported by the bloodstream to affect distant sites and tissues

Paracrine - molecules produced locally by one cell that have an effect on another

Autocrine - molecule produced locally and has an effect on the same cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How are growth factors produced?

A

Synthesised as large precursors

Cleaved by protease so to monomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do growth factors exert their effects?

A

Bind to growth factor receptors in the cell membrane

Induce intracellular signal transducers which affect transcription factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can be the overall effects of growth factors?

A

Can stimulate or inhibit growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Function of platelet-derived growth factor?

A

Stimulates proliferation of stromal cells and endothelial cells by paracrine mechanisms - important for angiogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where in platelets is PDGF found?

A

In their granules

N.B. can also be produced by non-platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Function of fibroblast growth factors?

A

Stimulate proliferation of fibroblasts, endothelial cells and smooth muscle cells - important for angiogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Function of transforming growth factor α?

A

Induces epithelial development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Function of transforming growth factor β?

A

Acts as a growth inhibitor of epithelial cells
Stimulates growth of fibroblasts
Stimulates production of extracellular matrix by increasing synthesis and decreasing degradation
Blocks activation of lymphocytes and macrophages
Can stimulate angiogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do growth factor receptors transducer the signal?

A

Binding of the ligand (growth factor) causes a conformational change in the receptor which activates the cytoplasmic tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Give some examples of growth factor receptors

A

Serine/threonine kinase

Tyrosine kinase receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can drive growth of a tumour?

A

Changes in the growth factor receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can cancer cells be stimulated by growth factors - like where do the growth factors come from?

A

Can be stimulated by systemic growth factors
Can produce their own growth factors
Induce surrounding benign cells to produce growth factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which growth factors can be used for angiogenesis?

A

PDGF

Fibroblast growth factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is HER2?

A

A gene that codes for a co-factor for EGFR and is seen in many breast cancers
Also now targeted in lung cancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In cancer, what does transforming growth factor α do?

A

Induces epithelial development
In breast cancer
-responsible for autocrine growth stimulation
-mediate mitogenic effects of oestradiol

17
Q

Function of transforming growth factor β in cancer?

A

Promote angiogenesis
Block them immune response
Inhibitory pathway often muted in cancer cells

18
Q

What can bind to epidermal growth factor receptors?

A

EGF

TGF-α

19
Q

What happens to EGFRs in many cancers? Which types in particular?

A

Amplified

Seen in squamous carcinomas and activating mutations in lung cancer

20
Q

What can cause genetic changes to TGFβ receptor II?

A

Microsatellite instability - the condition of genetic hyper mutability that results from impaired DNA mismatch repair

21
Q

What does the HER-2 receptor normally do?

A

Forms dimers with other type I tyrosine kinase receptors

22
Q

What can happen to HER2 to lead to cancer?

A

High expression - get gene amplification and over-expression in adenocarcinomas

23
Q

What can cause activation of PDGFR(B) receptor? Which cancers is it seen in?

A

Translocation between chromosomes 5 and 12 to form a fusion gene
An early event in development of chronic myeloid leukaemia

24
Q

What are some hydrophobic growth regulatory molecules?

A

Steroids - androgens and oestrogens
Thyroid hormone
Retinoic acid (metabolised Vit A)

25
Q

Which cancers are androgens and oestrogens promoters in?

A

Prostate cancer

Breast and endometrial cancer

26
Q

How can vitamin A slow progression of acute myeloid leukaemia?

A

Metabolised to retinoic acid

Induces differentiation in cancer cells of AML - slowing disease progression

27
Q

What are the three domains that steroid receptors share?

A

Hormone binding domain
DNA binding domain
Transactivating domain - induces transcription

28
Q

What happens when a steroid bins to the receptor?

A

Steroid binds to receptor
Receptor binds to hormone response element in DNA
Transcription factors and RNA polymerase are recruited to initiate transcription of targeted genes
Protein is synthesised and get a functional response

29
Q

What are the two types of oestrogen receptors and where are they present?

A

Classical or α form - present in breast, endometrium and myometrium

Secondary or β form - wider distribution

30
Q

What happens when receptors are bound to the hormone?

A

Receptor forms dimers which may be homo or heterodimers (αα, ββ or αβ)

31
Q

How are oestrogen receptors detected in tissue?

A

Immunohistochemistry - use routine pathology material

32
Q

Name some of the receptors in the steroid receptor family

A 
Glucocorticoids
Progesterone
Androgen
Oestrogen 
Mineralocorticoids 
Thyroid
Retinoic acid 
Vitamin D
33
Q

How can mutations causing upregulation of EGFR be detected?

A

Detect mutations by qPCR or sequencing methods

34
Q

How can detecting mutations activating EGFRs be a predictive marker of cancer? Which cancer is it used for?

A

Can target therapies - gefitnib

A minority of lung cancers

35
Q

So in general, which two types of receptors can growth factors act on?

A

Transmembrane receptor with intracellular kinase domains

Directly on nuclear transcription factors

36
Q

How can growth factors and receptors drive tumour growth?

A

If there is over expression of factors
Over expression of receptors
Alterations in receptors

37
Q

What are the two main forms of extracellular signalling molecules and how do they exert their effect at the target site? Give examples for each

A

Polypeptides (growth factors) - act through receptors in the cell membrane eg hormones and cytokines

Low molecular weight molecules - traverse the cell membrane and bind to intracellular receptors eg steroid hormones

Biology Of Cancer (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions