Is Cannabis a Cure-all?

You might have seen in the media lately a lot of coverage about the use of cannabis to treat epilepsy and other conditions. It all started with the case of a young boy with severe epilepsy who was using cannabis oil to manage his seizures, with apparently great effect. Until, that is, his mother was unable to bring his treatment into the UK and his medication was seized at the airport.

These stories raise three questions:

  • What does UK law regulate in the case of medications based on cannabis
  • What is a cannabis oil?
  • Can cannabis treat any medical condition?

UK Law

In the UK, cannabis is a Class B drug – you aren’t allowed to possess or supply it and doing so can result in jail-time. This is a regulation under the Misuse of Drugs Act 1971, however cannabis is also regulated by The Misuse of Drugs Regulations 2001 which control the therapeutic use of drugs. Under this legislation, cannabis is regulated as a Schedule 1 drug which means it is not available for medical purposes and possession and supply are prohibited unless the Home Office approves.

cannabis plant seedlings

Cannabis: the sum of its parts

Cannabis refers to a group of plants which produce compounds called cannabinoids. Cannabis plants contain 113 different cannabinoids – so what exactly are we talking about when we talk about cannabis oil?

The two important cannabinoids to consider are tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the main part of cannabis that gives its psychoactive effects. It’s the compound that will make you feel ‘high’ if you smoke marijuana although this response is mediated by other cannabinoids too. It also stimulates release of the hunger hormone, ghrelin, which explains why people have an increased appetite when they take cannabis. It does this by binding to a specific receptor on the surface of cells in the brain.

CBD is non-psychotropic and it acts in a very different way to THC. But it might also enhance THC activity by increasing the number of receptors available for THC to bind to. It might also increase the levels of those natural endocannabinoids in the body.

In the UK, CBD is legal which means cannabis oils containing only CBD are legally available whereas THC is not legal.

four brown glass unlabelled bottles containing oil

Can cannabis treat disease?

In the UK, there are already two cannabinoid based treatments licensed for prescription. Nabilone is used to treat nausea and vomiting in people undergoing chemotherapy. There are other conditions it has been indicated for including IBS, fibromyalgia, chronic pain and parkinson’s disease however in the UK it is only permitted to help treat the side effects of chemotherapy.

The second cannabinoid based treatment available in the UK is Sativex which is used to treat the symptoms of multiple sclerosis including neuropathic pain and spasticity. Sativex is a cannabis extract which contains both THC and CBD.

Cannabis for epilepsy

When it comes to epilepsy – there is considerable evidence that THC can control convulsions through regulation of neuronal excitability and inflammation. But because it can make you high – it’s not an ideal avenue for therapeutic exploration.

Research into CBD for treating epilepsy is relatively new but initially promising at least for certain types of epilepsy and there is a drug awaiting FDA approval which can treat Lennox-Gastaut syndrome and Dravet syndrome, two severe forms of epilepsy. But this might not be sufficient in all cases – some patients may require different mixtures of THC and CBD to see an effect.

Cannabis for cancer

Cannabis can be useful in managing cancer-associated side effects in patients. It can act as both a pain reliever and a way to reduce nausea and enhance appetite. But there is early research that it might also kill cancer cells and stop them growing. In these cases researchers have looked at highly purified THC and CBD. Some trials have shown that combining chemotherapy with cannabis might have some promise. However, we have insufficient evidence to support its use as a cancer treatment either due to small study sizes or the research predominantly taking place in cells in the lab which is just not a good representation of what would happen in humans. We don’t know which types of cannabinoids are most useful, what doses are needed, what types of cancer respond, how to take them effectively and whether they should or shouldn’t be combined with other treatments.

Cannabis research

If cannabis is so promising, why don’t we do more research on it to bring it to clinical trial? Cannabis is a Schedule 1 regulated drug, it can only be used in research with Home Office approval. Schedule 1 drugs are so classified because they are not deemed to have medical usefulness. But researchers like Professor David Nutt are concerned that the medical usefulness of cannabis cannot be proven if research is prohibited.

Importantly, the recent media interest in cannabis use as a medical treatment has been useful in encouraging a UK government review on the therapeutic value of medications based on cannabis. This review will be undertaken by the Advisory Council for the Misuse of Drugs and may lead to a change in the legal status of cannabis and cannabinoids with regards to their use in medicine.

A woman standing at a laboratory bench facing away from the camera and wearing a lab coat

Alternative medicine

In the meantime, it is important to remember that while cannabis holds some promise as a potential therapy for many conditions, it is crucial to always follow professional medical advice when considering medical treatments. The research supporting cannabis use is limited and there are many questions about safety and efficacy that remain unanswered. For many conditions that cannabis might be useful for, we already have good medical treatments that can be used before considering an as-yet, unproven treatment. Cannabis oils are poorly regulated and might have wildly variable levels of cannabinoids and may even contain ingredients that are harmful. It is never advisable to buy medical treatments online or take medical advice from someone other than a qualified medical professional.

 

I talked more about this on my podcast, Skeptics with a K – on this episode. You can follow me on Twitter @AliceEmmaLouise for more.

Is sunscreen bad for you?

The weather has been glorious here in the UK, which means out come all the warnings to apply sunscreen copiously and frequently. It also means out come all the warnings that chemicals in sunscreen are dangerous.

But what does the science say?

Types of sunscreen

There are two main types of sunscreen: chemical or mineral. Chemical sunscreens contain chemical UV filters such as octinoxate and oxybenzone and some have retinyl palmitate added to them. Mineral sunscreens contain mineral compounds like titanium dioxide and/or zinc oxide. Chemical sunscreens absorb UV light and convert it whereas mineral sunscreens are reflective and act as a physical barrier. This means mineral sunscreens are often thicker and have a less pleasant texture on the skin and they leave your skin a little ghostly.

image of a person's knee with white sunscreen and a hearth drawn into the sunscreen

Chemical sunscreen – The warnings

When we see warnings about the dangers of sunscreen it tends to be related to three things:

  • Does chemical sunscreen cause skin problems such as contact dermatitis?
  • Does chemical sunscreen cause cancer?
  • Does chemical sunscreen cause birth defects?

So what are these concerns based on?

Contact dermatitis

Some people have skin reactions to chemical sunscreens – this occurs in less 1% of users and can be a response to fragrances, preservatives or the UV absorber itself. Sensitivity can develop after using a particular formulation for a long time. If you have a sensitive reaction to sunscreen you can try switching formulations, or you can switch to mineral sunscreen which is less likely to cause a reaction. And of course, see your doctor if you’re worried.

Causing cancer

Some studies suggest that oxybenzone can cause hormonal changes in cells grown in the lab. These hormonal changes have been confirmed in animals like mice but have not been reliably shown to occur in humans. Hormone changes can cause cancer so some people believe that oxybenzone can cause cancer. To date this has not been shown to be the case. Oxybenzone has not been shown to cause the DNA mutations needed to cause cancer and hormonal changes are not always linked to cancer. This evidence is insufficient to prove any link between oxybenzone and cancer.

an image of a small white mouse standing on a white background

Retinyl palmitate is sometimes found in sunscreen. Retinyl palmitate is derived from retinol or vitamin A and it acts as an antioxidant. Retinol generates reactive oxygen species (ROS) when exposed to UV radiation and ROS are able to damage DNA. This is the basis for the concerns that Retinol will cause cancer. Studies in mice did not show that retinol combined with UV radiation causes cancer. There is no data published in humans to suggest that retinyl palmitate causes cancer.

A recent meta-analysis confirmed that there is no evidence supporting an increase in cancer risk caused by sunscreen use.

Causing birth defects

There is evidence that medicinal retinol pills can cause birth defects however this has not been shown to be the case with topical retinol application. Still, as a precautionary method it is advisable that pregnant women do not use a sunscreen containing retinols for the duration of their pregnancy.

The context

It is important to note that while there may be some evidence suggesting some level of risk associated with chemical sunscreen risk – this must be taken within the wider context.

Skin cancer

There are two main types of skin cancer – melanoma and non-melanoma skin cancer. Non-melanoma skin cancer includes basal cell carcinoma and squamous cell carcinoma and is largely treatable if it’s caught early. Non-melanoma cancers are the most common type of cancer. Melanoma skin cancer is an invasive form of cancer that is the 5th most common and at late stages is usually considered incurable. At early stages it is highly treatable but this form of cancer can progress rapidly and requires early intervention.  Both types of skin cancer are on the rise in the UK and this is linked to increasing sun and sunbed exposure. UV light exposure accounts for 86% of all melanoma cases, in the UK. Studies in Australia have shown a reduced rate of melanoma with regular sunscreen use.

A white sunhat with a black ribbon on a table with a pair of blue lensed sunglasses

Does sunscreen prevent cancer?

There is evidence that regular sunscreen use reduces pre-cancerous conditions and prevents skin cancer. However, the research into the efficacy of sunscreen is highly variable. This is partly because people are prone to using sunscreen in order to extend their time in the sun and misunderstand the most effective ways to use sunscreen. Chemical sunscreens should be applied to the skin 30 minutes before going into the sun and should be reapplied every two hours or more often if you are perspiring or swimming. Even waterproof sunscreen will be removed by towelling down after a swim. Sunscreen does prevent sunburn however research shows that people who only rely on sunscreen to protect themselves from UV damage burn more often than people who also practice sun avoidance habits. A person who has suffered sunburn more than twice in their life is twice as likely to get melanoma.

So what should you do?

While there is evidence that chemical sunscreens can have some detrimental effects on the body – the evidence is overwhelmingly clear that over-exposure to UV light causes skin cancer. Not only that, the research shows that the benefits of using sunscreen far outweigh the risks. Unless you are completely avoiding any UV light exposure then in my opinion, using sunscreen is a risk worth taking. In addition to wearing sunscreen and reapplying regularly, you should aim to avoid direct sunlight during the hottest hours of the day or wear clothing that covers your skin. And don’t forget, you might not burn through glass but you can still get UV skin damage through glass!

Extra reading:

https://www.skincancer.org/prevention/sun-protection/sunscreen/sunscreens-safe-and-effective

https://www.consumerreports.org/cro/sunscreens/buying-guide/index.htm

https://www.popsci.com/sunscreen-harmful#page-2

 

Kitchen cupboard “cures” – number one: turmeric

Wouldn’t it be great if we could cure all our ills with ingredients we can find in our kitchen cupboard? Plenty of people claim that it can be done and with the popularity of ‘natural’ medicines it’s not just your Nana who recommends it because that’s what her Nana taught her.

Kitchen cupboard remedies have become so mainstream that they become potentially dangerous when recommended for life-threatening diseases such as cancer. In fact, just a few months ago the Express asked “Can turmeric really cure cancer? Woman says benefits of golden spice ‘cured’ her disease”.

the express
Headline from the Express: “Can turmeric really cure cancer? Woman say benefits of golden spice ‘cured’ her disease”

But sometimes we wonder, if so many people believe it, maybe there’s really something in it?

In this series I will cover kitchen cupboard “cures” to investigate the claims made, and what the science really says. The series begins with the tasty Indian spice turmeric.

Turmeric

Turmeric is often reported as some sort of wonder spice. People who promote its use claim turmeric is anti-inflammatory, reduces cholesterol, treats diabetes, prevents Alzheimer’s disease and both prevents and cures cancer.

glass jar of orange coloured ground turmeric on a tea towel with a wooden spoon on the worktop next to it and turmeric on the spoon and counter

But actually, while this seems like a bizarre old wives’ tale, there is evidence supporting some of the claims for turmeric. The active ingredient in turmeric is curcumin or diferuloyl methane. Experiments in the lab show that curcumin alters the expression of genes in cells and some of these genes are related to specific pathways. For example, curcumin alters the expression of proteins related to inflammation in rat liver cells in a petri-dish and also alters the production of cholesterol in cells. Curcumin supplementation might also help manage some of the side effects of diabetes but only in conjunction with standard therapy. There is even some early evidence from mice with Alzheimer’s disease that curcumin can slow cognitive decline.

However, the science is also quite complicated. When it comes to cancer there is some evidence that curcumin can slow the growth of cancer cells in the lab but plenty of things slow cancer growth in the lab and never go on to prove useful therapies. Having said that, some clinical trials have shown that curcumin might one day prove useful as an adjunct to some cancer treatments in some cancer patients with some types of cancer.

The Express article above did discuss a case of a woman with myeloma, a type of blood cancer. This article was based on a single case published in British Medical Journal Reports in which a patient who had been on conventional treatment for many years suffered a relapse and was advised that there was nothing else doctors could do to help treat her cancer. The patient decided to take 8g chemical curcumin in tablet form per day in the hope it would treat her cancer. Her cancer has subsequently stabilised. This is a potentially interesting case – however it is only one single case that has been observed. Subsequent studies have not been done to investigate why this patient stabilised and there is insufficient evidence that it was the turmeric that was responsible. In fact, there are rare cases in which cancers such as myeloma can go into spontaneous remission without treatment and doctors believe this might be due to the patient’s own immune system targeting the cancer cells.

Important caveats

It would seem that the early research is fairly promising, however there are some very important caveats to remember here. So far, these studies are largely done in cells in a petri-dish or animals like mice or rats. We are not yet able to translate the findings to humans and we’re a long way from finding useful therapies using this compound.

Importantly, the studies use chemical curcumin rather than dietary turmeric and usually have specific measured doses. If curcumin becomes a useful therapy, the dose will change between different diseases and different patients. There is no evidence supporting the use of turmeric in isolation to treat disease. In all studies it is used as a supplement to standard therapy.

Clear capsules with orange powder inside

Medical treatments should always be managed by a medical professional. Any ‘herbal’ remedy has the risk of interacting with conventional drugs. In the case of curcumin research has shown that the chemical can inhibit some cancer treatments so it is important we understand the role curcumin plays in reacting with other medications before using this to treat patients.

It is because of this risk of interaction with other medications that it is really important patients taking any herbal remedy supplements speak to their doctors about whether these supplements might harm themselves or the efficacy of their treatments. It is important to note that many supplements are not fully regulated and therefore may contain ingredients that cause harm. For example, some curcumin supplements have been shown to contain anti-inflammatory drugs which can cause liver damage if taken in excess.

Summary: while there is some early evidence the active ingredient of turmeric might one day prove a useful supplement to conventional therapy we’re a long way from this being clinically useful. We need much more research to confirm the efficacy of curcumin and to establish which compounds work best and at which doses.

Next week I’ll be writing about Rosemary. If you have any specific requests for a Kitchen Cupboard “Cure” for me to cover, please leave a comment or send me a tweet @AliceEmmaLouise.

For more information on turmeric and cancer you can see CRUK’s review.

Sources:

 

 

 

Skincare, anti-aging (and cancer)

The world of skincare is not a place for the faint-hearted. It is such a dizzying mix of advice and recommendations, advertising and ‘science’ that any wander through this world leaves you feeling like you are not doing enough for your health or appearance. The only way to make yourself feel better, it would seem, is to spend sometimes hundreds of pounds on products you will use religiously for a few weeks before you end up exhausted by all the time you’re spending slathering on potions, oils and creams.

Why do we do it?

There are a range of reasons we feel we have to invest time, money and energy into our skin. One of the main reasons seems to be to maintain a youthful appearance for longer. Anti-aging is a huge part of skincare marketing and people (women especially) are targeted from an early age to start protecting their skin from the effects of aging.

The science of aging

There are two types of aging – intrinsic and extrinsic.

Intrinsic aging is the type that is genetically accounted for. It happens naturally pretty much no matter what you do. This is the kind of aging that leads to changes in skin elasticity. This type of aging is also called chronological aging and is the one you cannot really do much to change.  The characteristics of intrinsic aging include smooth, unblemished skin with a loss of elasticity, fine wrinkles and paling of the skin. The skin gets thinner and the small blood vessels in the skin reduce in quantity.

In addition to the natural course of aging, we also have extrinsic aging. This is the one our behaviour has a say in. By far, the two biggest factors which cause extrinsic aging are smoking and exposure to UV light.

Smoking reduces the elasticity of skin and reduces collagen levels in the skin. This means the skin gets hardened, slack and rough. We have evidence from multiple studies over a number of years showing that smokers have increased wrinkling compared to non-smokers. The evidence is consistent and overwhelming – smoking tobacco increases skin aging.

Photoaging

Exposure to UV light from the sun is thought to account for up to 90% of visible skin aging. UV light causes an increased level of specific proteins in the skin called enzymes. The enzymes that are increased in skin exposed to sunlight are responsible for degrading important connective tissue. After repeated exposure the skin starts to sag and to form wrinkles. Sunlight exposure increases the production of reactive oxygen species (ROS) and free radicals in the skin. ROS and free radicals damage the DNA which increases your risk of skin cancer, but they also increase the levels of those degrading enzymes even more. In addition to all of that, UV radiation interferes with the immune system and may even prevent cell death in sun-exposed skin which can also contribute to an increased risk of skin cancer. The characteristics of photoaged skin include nodular, leathery, blotchy skin with coarse wrinkles and furrows. The skin has irregular pigmentation and obvious marking on the skin and the elasticity is severely damaged. Blood vessels become dilated and there is pronounced inflammation.

What works?

It should be clear, now, that the two most useful ways to prevent visible skin aging are to minimise intake of cigarette smoke and to minimise skin exposure to damaging UV rays.

Sunscreen

To protect your skin from UV damage, applying a daily sunscreen with a high factor SPF and high-quality UVA protection (4 stars or above). SPF protects your skin from burning and from the damage associated with that but it does not protect against UVA radiation. UVA damage is invisible, although it does cause darkening of pigmentation, and is very deeply penetrating. You need a sunscreen that protects against both UVA and UVB damage.

image of a person's knee with white sunscreen and a hearth drawn into the sunscreen

Topical Retinoids

While most skincare products have very little evidence supporting their use in preventing or reversing the signs of aging, there is one active ingredient that does seem to help.

Retinoids are a family of chemicals which include retinol (vitamin A) and similar compounds. The potential of retinoids in treating aging was discovered in the 1980s when scientists treating photoaged mice noticed repair of the skin and reduction in wrinkling. We now know that retinoids encourage cell growth and can reverse some of the effects seen in photoaged skin and you can buy skincare products which have retinoids in them. There are two downsides to using retinoids on your skin – firstly, retinoids can cause some sensitivity making the skin red and sore which means some people cannot use it at all and most people need to build up their usage from a low dose (0.1%) used infrequently (1-2 times per week). Retinoids can also make your skin more sensitive to UV damage. This means if you are using retinoid skin products you need to be extra careful about staying out of the sun.

Prevention is better than cure

Ultimately, the best thing you can do for your skin to prevent visible aging is to protect it from harmful damage caused by smoking or sun damage. Of course, if you enjoy the relaxation of using different products on your skin, then go right ahead. But the best way to protect your skin is to use a decent sunscreen and to refrain from smoking.

You will also be doing wonders for your risk of lung and skin cancer!

Sources:

Read more about skin cancer here:

http://www.cancerresearchuk.org/about-cancer/skin-cancer/about-skin-cancer 

 

 

 

Trends in Pseudoscience: Raw Water

Trend:

Water consciousness movement/raw water

What is it?

The water consciousness movement is a trend towards eschewing tap or bottled water for drinking and instead turning to unfiltered, unpasteurised, unsterilised spring water.

But why?

Proponents and, indeed, suppliers of this trend say that tap water in the US has been filtered – removing bacteria and minerals that they believe benefit the body. One supplier of ‘raw’ or ‘live’ water, Live Water, claims that “you can attempt to remineralize filtered water, but those minerals will never be bio-available like in fresh living spring water”. The bacteria content in ‘live’ water is lauded with Live Water announcing “there could be countless other beneficial microbes present, scientists just haven’t discovered yet”. They claim that beneficial bacteria, which they refer to as probiotics, are crucial for the proper digestion of food and the promotion of good health. Not only that but some raw water proponents are fearful of fluoride present in tap water. The founder of Live Water, Mukhande Singh, told The New York Times “Call me a conspiracy theorist, but it’s a mind-control drug that has no benefit to our dental health.”

And why not?

The filtering process applied to US tap water is and important step in making water that is safe to drink. It removes bacteria which can include organisms like E.coli but also parasites and viruses. A telling indication of the microorganisms present in ‘raw’ water comes from Mukhande Singh who told The New York Times of his company’s ‘live’ water: “If it sits around too long, it’ll turn green. People don’t even realize that because all their water’s dead, so they never see it turn green”. Water going green over time is a sure sign that something is growing in it. The water is alive, just not in the way that Mr Singh claims. Water borne diseases are not a problem for many Americans, these days, because we solved the problem with the availability of clean drinking water. The blight of the 1800s, cholera, a disease caused by water contaminated with a bacterium called Vibrio cholerae taught us a lot about the dangers of drinking unsanitary water. Sufferers of the ‘blue death’ often succumbed to a rapid death caused by severe dehydration, a consequence of incessant diarrhoea and vomiting.

Cholera_bacteria_SEM
Scanning electron micrograph of the rod shaped cholera bacteria (Vibrio cholerae). Source: http://remf.dartmouth.edu/imagesindex.html

US tap water is carefully regulated to ensure safe levels of microorganisms. US tap water is fluoridated which is scientifically proven to improve dental health. But there’s another benefit to drinking water that is regulated to prioritise health and safety. These regulations are subject to changes based on the evidence as our scientific understanding of certain contaminants develops. For instance, arsenic naturally occurs in water. Since the 1960s the regulations sustained arsenic below 50ug/L but by 2006 all drinking water in the US was required to have a level of 10ug/L or less. Studies show that this reduction in the regulated level in US drinking water has resulted in a reduction in the diagnosis of lung, bladder and skin cancer each year.

‘Raw’ water, is not regulated in the same way. The contamination of each ‘batch’ of water might not even be monitored. Not only might customers be drinking dangerous contaminants – they have no idea of which contaminants and at what level might be present in the ‘raw’ water they consume.

Cool science: using Zika virus to treat cancer?

Throughout the last two years there has been a great deal of news on the Zika virus – a virus spread by mosquitoes which was first identified in 1947 in Uganda. In a normal healthy adult Zika fever causes relatively mild symptoms or even none at all however the 2015-2016 Zika epidemic gave rise to widespread concern due to its propensity to cause microcephaly and brain defects in babies infected with the virus during development. The epidemic was declared over in late 2016 although there are still travel warnings to certain areas where the mosquitoes known to carry the virus are prevalent.

But research into this particular virus highlighted an interesting trait that we might be able to take advantage of – Zika has a preference for stem cells.

Zika and stem cells

The reason Zika virus is particularly dangerous in developing babies is that the virus causes damage in stem cells in the brain. A stem cell is a cell that isn’t yet programmed. They’re really important in development because when you create a baby you start with one sperm cell, one egg cell and these cells needs to combine, proliferate and then differentiate into all the different types of cell within the human body. Stem cells are unique cells that can be programmed or ‘differentiated’ into all sorts of different types of cells. Once a stem cell has differentiated it can’t turn back into a stem cell – a differentiated cell is committed to only ever being that cell type. The adult body has very, very few undifferentiated cells but a developing foetus has plenty. This explains the risk of Zika infection during pregnancy as Zika has been shown to target neural progenitor cells – a type of undifferentiated cell in the brain – that might lead to the microcephaly seen in babies infected with the virus during their development.

480px-Zika-chain-colored
Crystal structure of the Zika virus

Zika and brain cancer

Cancer stem cells are quite a complicated thing that I’m not going to try and do justice in this post because it’s a topic that deserves its own post. Scientists believe that some cancers do have associated cancer stem cells. How exactly cancer stem cells might contribute to cancer progression is far from fully understood. However, we do believe that the presence of cancer stem cells might contribute to cancer therapy relapse. This is particularly concerning in glioblastoma – an aggressive form of brain cancer, which has poor survival rates despite our best efforts. Without treatment, median survival is around 3 months from diagnosis. With treatment we are able to extend that survival to 12-15 months however the cancer usually recurs. Scientists believe this recurrence is all down to the presence of cancer stem cells.

The study

So here’s the clever part. Cancer researchers know we have a problem in treating glioblastoma. They also realised that Zika virus is a relatively mild virus, which attacks stem cells. The adult brain doesn’t really have stem cells – unless the adult has glioblastoma. Cancer stem cells in the brain lead to cancer relapse; Zika attacks brain stem cells. Maybe we can make use of these two pieces of information.

So, scientists did some experiments. Firstly, they took some glioblastoma cells from patient tumours and they grew them in a dish in the lab. Then they infected them with Zika virus. They looked at either glioblastoma differentiated cells or glioblastoma stem cells. And they looked at the infection rate. Over 48 hours, over 60% of the stem cells were infected and this increased over time as the virus spread. The differentiated cells were infected too but not as much. What was especially interesting was that the stem cells infected with the virus had severely reduced ability to multiply and they had an increase in cell death. This was specific to only the stem cells and didn’t affect the differentiated cells. The virus kills cancer stem cells and prevents them from spreading.

Next the scientists took some patient tissue samples – this allowed them to look at a whole mixture of cells in a slightly more normal context without having to infect patients. They infected the tissue samples with Zika and saw that cancer samples were infected successfully and the virus only hit the stem cells and not the other cell types in the sample. They also looked at some brain samples from epilepsy patients and the virus didn’t infect them showing that the virus really is specific for stem cells!

jem.20171093
Glioblastoma tissue sample (from the paper)

 

Finally, they used the virus to treat mouse models of glioblastoma. They took mice with glioblastoma tumours in the brain and infected them with the virus. They saw that the tumours were much smaller and the mouse had improved survival when they were infected with the virus compared to control treated mice. They went on to show that they got an even better effect when combined with other glioblastoma treatments.

Benefits

Current treatments have two problems when it comes to glioblastoma. Firstly, the cancer stem cells make recurrence almost inevitable. This could drastically improve average survival times. Secondly, all brain cancer treatments have to be able to cross the blood-brain barrier in order to get through to the cancer cells. The blood brain barrier is an important way to keep things out of the brain where they might cause damage but it also serves as a way to keep brain tumours trapped in and harder to treat. Zika is great at crossing the blood-brain barrier.

What next?

We’re still such a long way from this being a useful patient treatment. In order to use this as a treatment we need to modify the virus in such a way that it will not spread from person to person and it will not cause the patient any harm. Currently virus work is always done in very specialised laboratories with expert training on how to prevent spread and with many, many precautions. If it were to be used as a therapy we’d need lots and lots of precautions to make sure it were safe. So far this has only been done in lab grown cells (albeit ones taken from patients mouse models of cancer. But it’s incredibly interesting research and a great example of how cancer research is so quick to develop and understand how we can take advantage of what we know about the disease and use that to treat it.

 

Please let me know in the comments if you’d like to see a post on any of the topics from this post – Zika virus, glioblastoma, stem cells?

If you found this interesting, please share it with three other people who might find it interesting too! Sharing cool cancer research gives us all a little more hope!

 

Image credit for the crystal structure of Zika: By Manuel Almagro Rivas – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=47941048

Cool Science: taking advantage of cancer cell biology for cancer treatment

One of the big problems when it comes to treating cancer using drugs is that these drugs flood the patient’s body and cause detrimental side effects when they reach areas other than the malignant tumour.  Cancer cells are derived from our own healthy cells – they’re hard to target specifically without also hitting our healthy cells. A lot of research goes into trying to get around this problem. I came across a particularly interesting study that I thought I’d share here.

Earlier this year Sofie Snipstad et al. published a paper in Ultrasound in Medicine & Biology titled “Ultrasound improves the delivery and therapeutic effect of nanoparticle-stabilized microbubbles in breast cancer xenografts”. This paper was particularly cool because of the rationale behind it. Nanoparticle delivery of drugs is something scientists have been working on for a little while. The premise is that you take your drug and you wrap it up inside a small protective bubble allowing the drug to travel to a specific site before it is released. Due to a quirk of cancer biology, this is particularly great as a cancer therapy. When tumours grow, they start to form their very own blood supply – only the blood vessels that they grow are more leaky than normal blood vessels. They allow slightly larger molecules to pass through from the blood vessel and into the surrounding tumour.  This means we can use nanoparticles to deliver cancer drugs specifically into tumour sites by allowing the particles to travel through these leaky blood vessels. But then we hit another problem – if the tumour blood supply doesn’t reach the very depths of the tumour then the particles are too big to get all the way through. You can treat the edges but not the very centre of the tumour. So, this paper worked on a special combination – they took a bunch of nanoparticles containing chemotherapy and they bundled them up together into microbubbles that can travel around the blood system easily and safely until they reach the tumour site. Then, the researchers used a focused shot of ultrasound to break up the bubbles and release the nanoparticles. This also served to allow gentle tissue massage by the ultrasound to allow the nanoparticles to distribute further throughout the tumour. Once in the tumour, the cancer cells start to take up the nanoparticles and inside the cell the drug is released and can kill the cancer cell from the inside.

Picture1Image: figure from the paper

Any microbubbles that weren’t in the tumour site and therefore not exposed to the focused ultrasound could be easily cleared from the body without releasing the drug which means the only cells targeted by the therapy are the cancer cells. This means we can hit the cancer cells with a higher, more toxic dose because the healthy cells are not going to be hit with the same dose.

The researchers in this paper were testing the optimal way of doing this in mice suffering with triple negative breast cancer – one of the more aggressive forms of the disease – with positive results. The mouse tumours took up the drug 2.3x better and there was no tissue damage identified. All of the tumours either regressed or else the mice went into complete remission. The authors described this as a “promising proof-of-concept study”.