Carla: Role of Cell Signalling In Disease Flashcards

1
Q

List some positive cues for cell cycle progression
(4)

A

Growth factors

Signalling molecules e.g. small peptides or proteins

Interactions with intracellular signalling pathways via hormones

Other small molecules -> mitogens

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2
Q

What do positive cues for progression do exactly?

A

They increase the activity of cyclins and Cdks

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3
Q

How do signalling molecules such as small peptides and proteins act as signalling cues?
(3)

A

Signalling molecules are detected by receptors

Signal transduction within the cell occurs

This brings about a response

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4
Q

Give an example of a small peptide signalling cue

A

Cytokines

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5
Q

Give an example of a positive progression cue cytokine

A

Granulocyte-macrophage colony-stimulating factor

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6
Q

Give three examples of positive cue signalling proteins

A

VEGF

EGF

PDGF

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7
Q

What type of hormones act as positive cues

A

Steroid hormones

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8
Q

Give three examples of types of steroid hormones that act as positive cues

A

Estrogen

Androgens

Progesterones

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9
Q

What are small molecules that act as positive cues called?

A

Mitogens

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10
Q

Give an example of a mitogen

A

ROS

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11
Q

List four negative cues for progression

A

DNA damage
Retinoblastoma protein Rb
p53
p21

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12
Q

What do negative cues actually do?

A

Decrease the activity of cyclins and Cdks

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13
Q

Where exactly do negative cues act?

A

The G1checkpoint

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14
Q

What is p53 often called?

A

The Guardian of the Genome

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15
Q

Why is p53 known as the Guardian of the Genome
(2)

A

It conserves stability by preventing genome mutation

The TP53 gene is classified as a tumour suppressor gene

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16
Q

Give three roles of p53

A

Triggers CDK1 proteins at G1

Activates DNA repair proteins

Programmed cell death

(Overall it maintains genomic stability)

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17
Q

Give two other names for p53

A

Tumour protein 53 (TP53)

Phosphoprotein 53

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18
Q

Where is the TP53 gene found?

A

Short arm of chromosome 17

Ch17p13.1

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19
Q

How long is the TP53 gene?

A

20,000 bp long

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20
Q

What can stimulate the expression of TP53?

A

UV light

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21
Q

What effect does p53 have on stem cells?

A

Important role in the regulation of stem cells

p53 levels are maintained at low inactive levels in human embryonic stem cells (hESCs)

p53 activation leads to rapid differentiation of hESCs

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22
Q

What does hESC stand for

A

Human embryonic stem cells

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23
Q

What two things will activated p53 do?

A

Cell will either enter cell cycle arrest

OR

Undergo apoptosis

24
Q

What happens if p53 puts a cell cycle into arrest?

A

DNA will be repaired

Cell cycle will be restarted

Cellular and genetic stability is restored

25
Q

What happens if activated p53 puts a cell into apoptosis?
(2)

A

Cell death and elimination of damaged cells will occur

Cellular and genetic stability is restored

26
Q

What are the two common traits in all cancer?

A

Abnormal cells

Out of control growth

27
Q

What four things can abnormal function of cells lead to?

A

Uncontrolled growth

Increased division

Decreased death

Other aberrant characteristics of cancer cells

28
Q

What are the three characteristics of malignant cancer cells?

A

Uncontrolled cell growth

Invasion

Sometimes metastasis

29
Q

What classifies as uncontrolled cell growth?

A

Division beyond the normal limits

30
Q

What classifies as invasion?

A

Intrusion on and destruction of adjacent tissues

31
Q

What classifies as metastasis

A

Spread to other locations in the body via lymph or blood

32
Q

What are benign cancers?

A

Tumours which are self-limited

They do not invade or metastasize

33
Q

Write a note on cancers
(5)

A

Can affect all animals

Can affect people of all ages including foetuses

For most varieties risk increases with age

Nearly all are caused by abnormalities in the genetic material of the transformed cells

Most form a tumour but some don’t e.g. leukaemia

34
Q

Categorise cancers

A

Carcinoma

Sarcoma

Lymphoma and leukaemia

Germ cell tumour

Blastic tumour/blastoma

35
Q

What are carcinomas?
(3)

A

Malignant tumours derived from epithelial cells

Most common cancers

e.g. breast, prostate, lung and colon cancers

36
Q

What are sarcomas?

A

Malignant tumours derived from connective tissue or mesenchymal cells

37
Q

What are lymphomas and leukaemia?

A

Malignancies derived from hematopoietic cells

38
Q

What are blood formoing cells called?

A

Hematopoietic cells

39
Q

What are germ cell tumours?
(3)

A

Tumours derived from totipotent cells

In adults these are often found in testicles/ovaries

In foetuses/babies/kids most often found on the body midline, particularly tip of the tailbone

40
Q

What are totipotent cells?

A

Stem cells that have the potential to develop into any cell found in the human body

41
Q

What are blastic tumours/blastomas?
(2)

A

A usually malignant tumour which resembles an immature or embryonic tissue

Many of these tumours are most common in children

42
Q

Classify hallmarks of cancer

A

Enabling hallmarks

Primary hallmarks

Emerging hallmarks

43
Q

What are the two enabling hallmarks of cancer?

A

Genomic instability and mutation

Tumour promoting inflammation

44
Q

What are the six primary hallmarks of cancer?

A

Invasion and metastasis

Evading growth suppressors

Replicative immortality

Resisting cell death

Sustained proliferation signal

Inducing angiogenesis

45
Q

What is angiogenesis?

A

The development of new blood vessels

46
Q

What are the two emerging hallmarks of cancer?

A

Evading immune destruction

Reprogramming Energy Metabolism

47
Q

How is cancer lethal?
(5)

A

Replacement of function with non-functional

Weakened immunity -> infections

Haemorrhaging

Tumour burden

Overall stress on heart, digestive system and kidneys

48
Q

What is meant by tumour induced haemorrhaging?
(3)

A

Tumours induce angiogenesis -> development of new blood vessels

The invading cells have an increased need for vasculature

This vasculature can intwine regular vasculature and cause a haemorrhage

49
Q

What is mean by tumour burden?

A

Tumour size and location can effect the function of an organ and the blood flow to the organ

50
Q

What is the genetic basis of cancer?
(6)

A

Amplification or activating mutation in oncogenes

Loss or inactivating mutation in gene involved in tumour suppressor genes TSGs

Generation of a fusion gene with cell cycle promoting activities

Alterations in promotor activity

Loss or inactivating mutation in a gene involved in DNA repair or apoptosis

Viral involvement

51
Q

What are oncogenes?

A

Genes involved in promoting cell division

52
Q

What are tumour suppressor genes?

A

Genes involved in halting cell division

53
Q

How do tumours induce angiogenesis?
(4)

A

Tumour proliferates and causes hypoxia

Hypoxia induces expression of VEGF

VEGF stimulates angiogenesis

=> rapid tumour growth and metastasis

54
Q

What molecule induces angiogenesis?
(2)

A

VEGF
Vascular endothelial growth factor

55
Q

What is the typical route of metastasis?
(6)

A

Tumour forms

Cells become invasive and enter capillary

Cells travel through bloodstream

1 in 1000 cells survive and adhere to blood vessel wall in other organs

Cells escape from blood vessel to form micrometastasis

Cells colonise liver forming full-blown metastasis