"Getting to the root of the problem
Cancers are a bit like weeds in the garden – they look like their neighbours but take up space and out-compete other plants, and have the potential to run riot over the entire garden if left uncontrolled.
As all good gardeners know, the best way to get rid of weeds for good is to destroy their roots. Fail to do this, and they’ll just start growing again.
In a similar way, blood vessels are the ‘roots’ of a tumour, feeding it and allowing it to grow bigger. Targeting these roots and cutting off the blood supply should therefore be a good approach for treating cancer. And that’s exactly what many researchers in the field of tumour angiogenesis are trying to do."
http://scienceblog.cancerresearchuk.org ... d-vessels/
Getting to the root of tumor blood vessels
Re: Getting to the root of tumor blood vessels
"Unexpected effects
To try and understand the disappointing results of anti-angiogenic drugs, scientists took a closer look at what was happening to blood vessels inside tumours in response to the treatment. What they found was unexpected (although our researchers Alan Le Serve and Kurt Hellmann had actually predicted this might happen back in the 1970s). Instead of destroying tumour blood vessels, anti-angiogenic drugs seem to make the strange and disordered capillaries become more normal.
At first, people thought this spelled disaster for the whole concept of anti-angiogenic therapy – surely if the treatment makes the tumour blood vessels better at their job, the cancer will just grow and spread faster. This is the opposite of what doctors and their patients want!
But on closer inspection, this ‘normalisation effect’ actually looks like it might be a positive thing – if we can catch it at just the right time. Here’s why:
Making tumour blood vessels better at delivering nutrients and oxygen to the tumour can have positive effects on some cancer treatments. For example, if chemotherapy is given together with anti-angiogenics, the more efficient blood flow means more of the chemo drug can get to more of the cancer cells to kill them. This explains why drugs like bevacizumab seem to work better when given alongside chemo.
Because of their disorganised blood supply, many tumours have relatively low oxygen levels – a phenomenon known as hypoxia – which seems to protect cancer cells from being destroyed by radiotherapy. Stabilising blood vessels means that more oxygen gets into the tumour, raising oxygen levels inside it. This could help to make radiotherapy more effective.
As tumour blood vessels become more normal, they seem to attract more supporting pericytes, which help to secure capillaries against wandering cells. Some researchers have shown that this could reduce the risk of cancer spreading (metastasis), which happens when cancer cells enter the bloodstream and travel to another site in the body. If entering blood vessels becomes more difficult for cancer cells, this could be a good way to protect against cancer spread.
Combining all these things together, it seems that while anti-angiogenics might not be useful in the way we originally thought (by killing blood vessels and starving tumours), they might instead make the other kinds of treatments even more effective."
To try and understand the disappointing results of anti-angiogenic drugs, scientists took a closer look at what was happening to blood vessels inside tumours in response to the treatment. What they found was unexpected (although our researchers Alan Le Serve and Kurt Hellmann had actually predicted this might happen back in the 1970s). Instead of destroying tumour blood vessels, anti-angiogenic drugs seem to make the strange and disordered capillaries become more normal.
At first, people thought this spelled disaster for the whole concept of anti-angiogenic therapy – surely if the treatment makes the tumour blood vessels better at their job, the cancer will just grow and spread faster. This is the opposite of what doctors and their patients want!
But on closer inspection, this ‘normalisation effect’ actually looks like it might be a positive thing – if we can catch it at just the right time. Here’s why:
Making tumour blood vessels better at delivering nutrients and oxygen to the tumour can have positive effects on some cancer treatments. For example, if chemotherapy is given together with anti-angiogenics, the more efficient blood flow means more of the chemo drug can get to more of the cancer cells to kill them. This explains why drugs like bevacizumab seem to work better when given alongside chemo.
Because of their disorganised blood supply, many tumours have relatively low oxygen levels – a phenomenon known as hypoxia – which seems to protect cancer cells from being destroyed by radiotherapy. Stabilising blood vessels means that more oxygen gets into the tumour, raising oxygen levels inside it. This could help to make radiotherapy more effective.
As tumour blood vessels become more normal, they seem to attract more supporting pericytes, which help to secure capillaries against wandering cells. Some researchers have shown that this could reduce the risk of cancer spreading (metastasis), which happens when cancer cells enter the bloodstream and travel to another site in the body. If entering blood vessels becomes more difficult for cancer cells, this could be a good way to protect against cancer spread.
Combining all these things together, it seems that while anti-angiogenics might not be useful in the way we originally thought (by killing blood vessels and starving tumours), they might instead make the other kinds of treatments even more effective."
Debbie