L6 - Invasion and Metastasis I

Question 1

The uncontrolable growth of cancer cells at a specific site is known as …

Answer 1

Primary cell mass

Question 2

How many deaths does the primary cell mass causes

Answer 2

10%

Question 3

What is responsible for the other 90% of deaths

Answer 3

When the cancer spreads to secondary - distal sites - this is known as metastasis

Question 4

Stages of the invasion-metastasis cascade

Answer 4

Primary tumour formation
Localised invasion
Intravasation
Transport in the circulation or lymphatic systems
Arrest in microvessels of various organs
Extravasation
Formation of a micrometastases
Colonisation and formation of a macro metastasis

Question 5

Is the secodnary organ that a cancer cell ends up at random?

Answer 5

No

Cells from different cancers are able to migrate to specific organs

Question 6

What organs does breast cancer tend to metastasise to

Answer 6

Lung
Brain
Bone

Question 7

What are cancers from epithelial cells known as

Answer 7

Carcinomas

Question 8

Why are carcinomas initially known as benign

Answer 8

BEcause surrounded by basement membrane - confines the cancer to a specific environment

Question 9

When does a benign tumour become dangerous?

Answer 9

When the basement membrane has been breached

Cancer cells are then able to invade into the surrounding stroma

Question 10

how can breaching of the basement membrane be visualised in vitro

Answer 10

Using a breast cancer organoid

Question 11

What is important to allow intravasation

Answer 11

Interaction between the cancer cells and macrophages and the endothelial cells

Question 12

Describe what live cell imaging has shown regarding the cancer cells interactions with macrophasges

Answer 12

Tumour cells come close to and interact with macrophages
Close to the endothelial wall
After this has occured the tumour cells are able to invade through the wall of the vessel

Question 13

Why is live cell imaging of the intravasation interactions hard to get

Answer 13

Since frequency of these events occuring is v low

Question 14

Extravastion occurs when …

Answer 14

Cells become physically trapped within the small vessels of organs

Question 15

What must occur during extravasation

Answer 15

Cells must escape the vessel and penetrate the surrounding organs

Question 16

What interaction fascilitates the extravasation

Answer 16

interaction with macrophages

Question 17

How can confocal microscopy allow us to visualise extravasation

Answer 17

Two focal planes
Above and below the wall of the vessel

Can see a cell vanish from one focal plane and appear in another as that cell crosses the wall

Question 18

How do micrometastases form

Answer 18

Once cells arrive at the secondary site they form little clumps
Can remain like this for several years

Question 19

What is growth of a micrometastasis known as

Answer 19

Colonisaion

Question 20

Why is colonisation the most difficult step of invasion-metastasis

Answer 20

Since foreign tissue doesnt provide the support that cancer cells had in their primary tumours

Question 21

The fact that their is a low prob of a cell completing all of the steps of the cascade is known as …

Answer 21

Metastatic inefficiency

Question 22

What s the first step of the cascade

What does it involve

Describe this

What is this process known as

Answer 22

Localised cell invasion

Major phenotypic changes - since the organisation of epithelial cells is normally incompatible with motility

EMT

Question 23

What does the EMT involve

Answer 23

Loss of E characteristics

Gain of M characteristics

Question 24

Examples of some charactertistics that are lost during the EMT

Answer 24

Cytokeratin expression
Tight junctions and adherence junctions involving E-Cadherin
Epithelial cell polarity
Epithelial gene expression program (e.g. catenin)

Question 25

Examples of some characterstics that are gained during the EMT

Answer 25

``` Fibroblast like shape Motility and invasive potential Mesenchymal gene expression (fibronectin) Protease secretion (MMPs) Vimentin expression ```

Question 26

How can we visualise the EMT occuring

Answer 26

Immuno staining for various E and M characteristics | Can see changes occuring

Question 27

Describe how invasion and E-cadherin expression was monitored in vivo What were the conclusions

Answer 27

Breast cancer cells expressing fluroro-E-cadherin and cancer cells marked with YFP As a cell migrates away this can be seen to be associated with the loss of CAM E-CAD

Question 28

What is further evidence from platelets regarding the importance of the EMT

Answer 28

In circulation cancer cells interact with platelets Causes more EMT Fascilitates extravasation

Question 29

At the end of metastasis what transition is required Why

Answer 29

MET required To allow micrometastases to form macrometastases Need to gain cell contact to allow survival

Question 30

Historically what was though of the EMT How has this changed

Answer 30

Binary process - cell is either mesenchymal or it is epithelial Now thought to be a gradual process with numerous intermediate states

Question 31

What do these intermediate states confer

Answer 31

Specialist properties

Question 32

When is a cell more suited to proliferate

Answer 32

When fully epithelial

Question 33

When is a cell better suited to invade

Answer 33

When fully mesenchymal

Question 34

When is a cell better suited to metastasise

Answer 34

When it is a hybrid

Question 35

What three things is EMT also involved in

Answer 35

Cancer stem cells Chemoresistance immunotherapy resistance

Question 36

How is EMT involved in cancer stemness

Answer 36

Small fraction of the cell within the tumour Tumour initiating potential and the abiluty to give rise to a varietn of cell types Activation of EMT linked to the acquisition of stem cell like properties

Question 37

How is EMT involved in chemoresistance

Answer 37

EMT contributes to resitance to chemotherapy | Can target to overcome chemoresitance

Question 38

How is EMT involved in resistance to immunotherapies

Answer 38

Epithelial tumours are more suseptible to immunotherpay | So would be better to treat cance rif we could inhibit EMT and render the cells epithelial

Question 39

What are the three TFs involved in the EMT

Answer 39

SNAIL TWIST ZEB

Question 40

What is SNAIL improtant in

Answer 40

Breast cancer metastasis to the lung

Question 41

What are both Zeb1 and 2 ivolved in promoting

Answer 41

Cell migration and invasion in breast and colorectal cancers

Question 42

What is Zeb1 expression required for

Answer 42

Efficient invasion and metastasis n a mouse pancreatic cancer model

Question 43

What are EMT TFs turned on in response to

Answer 43

Pleotropic signals

Question 44

What is the net effect of the EMT TFs

Answer 44

Inhibition of E genes | Expression of M genes

Question 45

The fact that cancer cells can migrate into the stroma in a variety of ways means

Answer 45

Cancer cells can adapt and adopt different morphologies and migration characteristics depending on their environment

Question 46

Characteristics of single cell migration

Answer 46

Lack of cell interaction during migration Uncordinated (different cells do different things) Can dispay different phenotypes

Question 47

Describe the different phenotypes that can be seen by single cells migrating

Answer 47

Ameoboid-like - round cells with short or blebbing protrusions Mesenchymal-like - elongated body and longer protrusions

Question 48

Characteristics of collective cell migration

Answer 48

Retention of adhesions

Question 49

How do cells move during collective migration

Answer 49

As one linear strand or as a broad sheet

Question 50

What properties does the leader cell have

Answer 50

Mesenchymal characteristics | Likely to be an intermediate phenotype

Question 51

Can cancer cells switch their methods of migration?

Answer 51

YES This is known as plasticity

Question 52

Give some examples of migrational plasticity

Answer 52

Can go single Collective OR Transition between the different modes of singe cell migration

Question 53

What is the chanllenge when designing treatments for anti-metastats wrt cell migration

Answer 53

Targetting the determinants of a single migration mode unlikley to block metastasis

Question 54

So what is the overall strategy when designing treatments to prevent metastasis (wrt migration)

Answer 54

Target the master regulators controlling plasticity This will hinder the ability of cells to switch between the migration modes