Edmead lecture 5 - metastasis

Question 1

Once cancer becomes metastatic therapy must become ______ which opens up the possibility of ___ _____.

Answer 1

Systemic

Side effects

Question 2

Only some cells within the tumour mass can ______. These are possibly the earlier, less ____, stem cell like cells of the tumour that can adapt to different ______/_____ and grow elsewhere. Whereas more _______, _____ cells probably can’t grow elsewhere as they are more restricted.

Answer 2

Metastesis
Differentiated
Environments/niches
Differentiated, progenitor cells

Question 3

Metastasis is the ability of cancer cells to break away from site of _____, travel to and ______ a distant site. This is one of the differences between ____ and ______ growths. ____ stay encapsulated in one localisation and are _____ to remove in surgery. _____ are invasive, difficult to tell the boundaries of growth and spread into other tissues.

Answer 3

Origin 
Colonise 
Benign and malignant 
Benign 
Easier 
Malignant

Question 4

About ___% of solid tumours have metastasised at the time of ______. Often this is the time when patients present with_____. Checking the body regularly and being familiar with the body can help diagnose quicker. This is important as once cancer has metastasised, this is a poorer _____ for the patient.

Answer 4

50%
Diagnosis
Symptoms
Prognosis

Question 5

Issues with metastases:
Spread of cells throughout body results in:
1) physical ____
2) competition with normal cells for ____ and __
3) Invasion and interference with ____ function

Answer 5

Obstruction
Nutrients and O2
Organ

Question 6

Metastasis requires a ___ ____ in cell-cell ____ and degradation of the _____ ____. So tumour masses involve cells that are attached together in a ball/mound/layer due to cell-cell ____. This needs to break and the cells need to break through the ________ matrix and then be carried through the body usually in the ____ _____. The cells then need to break out of the _____ ____ into tissues back through the ______ matrix so they can regrow and colonise.

Answer 6

Break down 
Adhesion 
basal lamina 
Adhesion 
Extracellular 
Blood vessels
Blood vessels 
Extracellular

Question 7

Mutations in _-____ cause them to relax and breaks cell-cell ____. This is essential as cells must break free from constraints that link adjacent cells. _-____ acts as a _____ _____ as it normally functions to secure cell cell _____ and suppress metastasis of tumour cells to distant sites. Transfection of _-____ gene into metastatic epithelial cells can render them non-invasive. Mutations in the extracellular domain and _____ in the promoter region of the _-_____ gene has been identified in prostate carcinomas. Hence metastasis can occur.

Answer 7

E-cadherins 
Adhesion 
E-cadherins 
Tumour suppressor 
Adhesion 
E-cadherin

Question 8

Integrin receptors mediate cell-_ _ _ interactions and intracellular signal transduction. Altered integrin receptor expression in tumour cells enable mobility and invasion of metastasising cells by modifying membrane distribution and allowing adherence to different _ _ _.

Answer 8

ECM (extracellular membrane)

ECMs

Question 9

MMPs degrade components of the _ _ _. This allows cells to move through it and recolonise other areas. The protein that produces MMPs is often __ regulated in tumour cell membranes. This allows more degradation to occur so more cells can metastasise.

Answer 9

ECM

Up regulated

Question 10

Intravasation of tumour cells occurs once the ____ _____ has been ______. This leads to entry of tumour cells into ____/lymphatic vessels. These cells home towards the nearest blood cells through the endothelium and back into other tissues.

Answer 10

Basal lamina
Degraded
Blood

Question 11

Targeting metastasis can be challenging as extravasation is a process that is used by ___s - interfering with _____ molecules may also prevent ___s coming out of tissue to fight infection. As well as cancerous cells. Targeting MMPs, integrins and selectins is not _____ enough for tumour cells - may lead to ___ ____ or lack of ____.

Answer 11

WBCs 
Adhesion 
WBCs 
Specific 
Side effects
Efficacy

Question 12

There are two theories that attempt to explain why tumour cells move to certain sites to metastasise.

1) 1st pass organ - explain
2) Pre metastatic niches - explain

Answer 12

1) 1st pass organ - Tumour cells are carried through the blood stream, the blood slows at the next major organ in the body and the tumour cells then move from the blood into the tissue of the organ and recolonise it. So you can look at the 1ry tumour and then the next organ that the blood flows to to try and predict the next site of metastasis - not seen in all cases
2) Pre metastatic niches - Similar principle to stem cells and nurse cells. Tumour cells can recolonise in tissue that has similar growth factors to the site of the 1ry tumour. So the tumour cells move to a niche that provides the growth factors that it requires to grow. OR the secondary site may be prepared to receive the tumour cells so the required nurse cells/growth factors are sent to that site in advance. It was found that factors secreted from 1ry tumours acted on downstream 2ry sites. If the 1ry tumour was removed then recolonisation didn’t occur so recolonisation depends on factors released from the 1ry tumour e.g. cytokines or growth factors. BUT also cases where remove 1ry tumour then 2ry tumours grew so may be tumour suppressing!

Question 13

Metastatic colonisation can’t occur without formation of new blood vessels (______) as the tumours need _____ and ___ to grow

Answer 13

Angiogenesis

Nutrients and oxygen

Question 14

Often tumours have a ____ core as the outside of the tumour has a good ___ supply meaning it receives the ____ and ____ it needs to grow. These cannot get to the middle of the tumour due to poor ____ supply. This results in some tumour cells responding differently to drugs. E.g. the cells on the ____ are killed off but the ones in the inside with less ___ supply feeding them don’t receive the drug as don’t die. If just one cell is left than this one cell can _____.

Answer 14

Necrotic 
Blood 
Nutrients and oxygen 
Blood
Outside 
Blood
Recolonise

Question 15

Cancer tumour cells want a good blood supply so they can grow and we want cancer cells to have a good blood supply so we can deliver ___ to them.

Answer 15

Drugs

Question 16

Name 3 times that angiogenesis normally occurs.

So these processes don’t often occur in mature humans. This represents a different that tumour cells shave so this could be a good ____. If you cut off tumours blood supply then you starve the tumour of ____ and ____ so it dies.

Answer 16

1) Embryogenesis
2) Menstruation
3) Wound healing - repair damaged blood vessels

Target
Nutrients and oxygen

Question 17

Angiogenesis is controlled by endogenous angiogenic growth factors and inhibitors. Growth factors cause blood vessel growth and ___. E.g. ___, ____ (platelet derived growth factor) and ____ (vascular endothelial growth factor)
Angiogenic inhibitors: _____ and _____ normally there is an _____ of these to keep the process dampened down and if need to repair blood vessels then reactivate angiogenic growth factors then dampen down again once done.

Answer 17

Repair
FGF, PDGF, VEGF
Angiostatin and endostatin
Excess

Question 18

Angiogenic process:

1) Surrounding cells e.g. stromal/______ cells or tumour cells in tumour release ______ factors
2) These bind specific GF receptors on nearby _____ cells causing them to become activated.
3) ______ cells then produce enzymes through _____ _____
4) Enzymes digest _____ _____ to make a hole in the blood vessel
5) Once a hole is made the _____ cells proliferate and divide and migrate out of the hole
6) _____ molecules and ____ aid formation of growing blood vessel. The _____ digest the ECM to make room for the growing vessel
7) The new vessels are stabilised by _____ ____ cells and pericytes.

Answer 18

1) endothelial - angiogenic growth
2) endothelial
3) endothelial - gene transcription
4) basement membrane
5) endothelial
6) Adhesion - MMPs - MMPs
7) smooth muscle

Question 19

In angiogenesis: blood vessels grow and sprout towards the source of the ______ ____ that induced it. e.g. towards a tumour that secretes ____. The ____ binds receptors on endothelial cells causing them to grow towards the tumour so it receives its own blood supply.

Answer 19

Angiogenic factors
VEGF
VEGF

Question 20

Tumour cells can switch on ____ production. It must be transcribed and translated. Oncogenes and hypoxic factors e.g ___ switch on ____ production.

Answer 20

VEGF
HIF
VEGF

Question 21

Designing an anti-angiogenic agent is hard because not all tumours utilise the same angiogenic growth factors. E.g. not all tumours use ____. So if design an agent against ____ and the tumour doesn’t use it then it won’t be efficacious. Alternatively, if the tumour does use ____ and this agent prevents it’s activity then the tumour may utilise an alternative angiogenic growth factor!

Answer 21

VEGF

VEGF

Question 22

There are _ forms of VEGF. VEGF_ is the ____ in cancer. Its expression is switched on by oncogenes and hypoxia mediated stabilisation of ___ _____ that drive VEGF expression.

Answer 22

5
VEGFA is the ligand in cancer
Transcription factors

Question 23

How to target VEGF:
1) can try to _______ levels of _____ _____ e.g by using an ______ RNAI approach to knock down levels of angiogenic factors e.g bFGF or PDGF

2) Can try to mop up xs ____ ____ by using soluble _____ or with ______ _____. E.g ______ that mops up excess ____ targets the ligand not the receptor and it prevents it binding the receptor. ______ __ = _____ which is used in _______ _____ _____. It inhibits blood vessel growth and prolongs survival. Can give this in combination with cytotoxic drugs e.g. _-__ or other kinase inhibitors e.g. the ____ inhibitor Erlotinib.
3) Enzyme inhibitors can also be used. Enzymes with an intrinsic _____ ____ can be targeted. Can block the _____ domain with small molecule _____ ____ inhibitors. This blocks the receptor signalling as it blocks __________ e.g Sorafenib or Sunitinib.

4) Activation of tumour suppressors - e.g. ___.
___ can up regulate anti angiogenic factors e.g. thrombospondin, endostatin or angiostatin or down regulate bFGF. But if lose activation of ___ then alter the balance and imbalance of proangiogenic factors and no apoptosis so allow tumours to induce blood vessel supply and grow more. SO reinstating ___ can help up regulate anti angiogenic factors.

Answer 23

1) Downregulate
Growth factors
antisense

2) growth factor
receptors 
monoclonal antibodies 
Antibody
VEGF 
Monoclonal antibody = Avastin 
Renal cancer patients 
5-FU
EGFR

3) Kinase domain
Kinase
Small molecule tyrosine kinase
Autophosphorylation

4) P53
P53
P53

Question 24

Issues: majority ineffective against established tumours due to the fact that they have established ____ vessels. These agents only prevent the formation of new ____ vessels. Long term treatment may also impair _____ ______.

Good points:
Might be useful to prevent _____ if caught early enough. Can use in combination therapy with lower dose ____ drugs or other angiogenics acting at different stages.

Answer 24

Blood
New
Wound healing

Metatasis
Cytotoxic

Question 25

Novel therapies are aimed at breaking down existing blood vessels so once tumour has undergone angiogenesis. Can we identify and target these vessels without targeting normal ____ ____ supply. Main difference between tumour vessels and established blood vessels is that tumour vessels have ________ which is weak and ____ and tumour cell puts the vessels together too quickly.

Answer 25

Blood vessel
Neovasculature
Weak and leaky

Question 26

Integrins have also been targeted. Humanised monoclonal antibodies against ____ integrin. This is antiangiogenic. It is called _______. Integrins _____ new blood vessels so targeting them means blood vessels are harder to form. But these integrins are fairly _____ so hard to specifically target.

Answer 26

Avb3
VITAXIN
Stabilise
Ubiquitous

Question 27

ANET is an antineovascular therapy. Can aim to direct _____ drugs. e.g. adrinamycin or dominant negative molecules e.g. mutant raf to EC. Direct to tumour. But this requires specialised drug delivery systems e.g. ____. These can exploit the ___ effect and accumulate in tumours.

Answer 27

Cytotoxic
Liposomes
EPR

Question 28

Vascular gene therapy:
Deliver genes into the body e.g. like adding WT ___ (Advexin). In order to do this you need to identify an appropriate ____. Need to deliver the gene to the area where the tumour is. Can add _____ to liposomes containing cytotoxic drugs to deliver them to the target.

Answer 28

P53
Gene
Antibodies

Question 29

Need to try and find a molecule that is only present in the cells you want to target. E.g. _-____ the adhesion molecule is produced by ______ cells so allows targeting of the ECs. Can use retroviruses to deliver the genes. They infect cells and carry the gene we’re introducing. RV specifically target the _____ cells. Can link the retroviral delivery mechanism carrying the gene to the EC to a specific promoter. The promoter region of _-____ is only activated in the EC as the EC has the ______ ____ needed to switch on the gene ____ of the protein. Can fuse this promoter region to a dominant _____ form of ____ receptor which doesn’t signal. This can circulate round the body but is only activated in the tumour ECs.

Answer 29

E-Selectin 
Endothelial 
Proliferating 
E-Selectin 
Transcription factors 
Transcription 
Negative 
VEGF

Question 30

Using gene therapy to incorporate a dominant _____ form of the ____. This will then be expressed at higher levels by the endothelial cells. VEGF produced by the ___ binds the receptor but the receptor doesn’t _____ so the EC don’t proliferate and angiogenesis is restricted.

Answer 30

Negative
VEGFR
Tumour
Signal

Question 31

Avastin (______) is a _____ ______ ab that mops up the _____ ligand. In trials it _____ blood vessel growth and prolonged survival in metastatic renal cancer. It can be given in combination with _____ drugs e.g. _-__. It is ____ to reduce the chance of immune response against the murine parts but it is too expensive to use _____ mice to reduce the immune response further.

Answer 31

Bevacizumab
Humanised, monoclonal antibody 
VEGFA ligand
Reduced 
Cytotoxic (5-FU)
Humanised 
Transgenic