Could cannabis cure cancer?

Chemicals in cannabis have shown promising results in halting the growth of cancerous cells in the lab. But will this translate into a cure?
23 February 2015

Interview with 

Dr Wai Liu, St George's, University of London


Cannabis plant


Cannabis plantCannabis contains many chemicals, some of which can be used to help people with MS in the drug Sativex. Another disease that might stand to benefit from certain compounds from the plant is cancer. But will the exiting lab results translate to an actual medical treatment, and is self medicating a good idea? Wai Liu, from St George's University of London, took Kat Arney through the research...

Kat - So, I mean when it comes to talking about cannabinoids and cancer, there's the aspect of relieving pain and palliative care. But there's a whole other aspect that's very exciting and that's potential of cannabinoids to treat cancer. Tell me about the kind of research that's been done into these cannabis chemicals and whether they have any effect on cancer cells.

Wai - Yeah, so these cannabis type drugs, the ones we really focus on are the THC every people have been talking about and also the CBD compound which seems to lighten the psychoactive properties. And most of these work have been really performed in lab based studies and also, some animal studies. And they've been shown to be quite active. They have the ability to really reverse that effects that cancer cells have on bodies and in doing so, somehow reverse the whole process that we don't want to see cancer breeding and growing.

Kat - So, tell me a little bit more about how cannabinoids are actually acting on cancer cells? What do they seem to be doing?

Wai - So, what we've seen is that cannabinoids, how they get in, we're not too sure. Sometimes they bind to these receptors that people have been mentioning and sometimes they can actually enter the cancer cells using different pathways which we're not too sure right now. What they seem to do, they tend to target these so-called signalling pathways. What these are, these are some pathways that are mutated in cancer cells which turns a normal cell into a cancer cell.

Kat - They're like the signals that tell cells to kind of keep growing, grow out, control.

Wai - Absolutely. So, these cells are growing out to control and lots of drugs out there, currently at the moment are trying to target these particular signalling pathways. And what we've shown that this THC and CBD compounds can actually turn these signals off and in doing so, reverse the process of cancer.

Kat - Now, there's a lot of very exciting lab research, things in animal studies but also from all kinds of cancer drugs that people are researching, they seem to work really well in the lab. you get great results in animal tumours and then you take them into the clinic and they don't seem to work in patients. Where are we with turning the lab research and the huge number of papers that have been published into finding out whether this actually works in patients?

Wai - I think we actually are really in exciting time right now. It is this transition from lab based research and transiting it into medicine into the clinic.

Kat - But have there been any clinical trial so far?

Wai - There's clinical trials ongoing at the moment and I do know 1 or 2 are actively recruiting in the UK and in the US. But the only one that's been reported in the past, the results haven't been great. The reason being, it's difficult to actually get the right mixture of the drugs that everyone's been talking about in this programme. So, the difficulty is to optimise the doses that we need to use of either THC or CBD and once we establish those - and these are precisely what these clinical trials are attempting to do. I'm almost certain we should get some good results.

Kat - And in terms of cannabis for cancer, sometimes people might say, should you just go down to the corner shop, buy some cannabis and start taking it. Is that going to treat people's cancer? Is that going to be effective?

Wai - That's one question I get asked quite a bit. This whole idea that, "Can we take cannabis rather than cannabinoids?" I suppose, the honest answer is, we don't know. There's lots of anecdotes. We often see on the net many, many times where cannabis oil can be used effectively to treat cancers. I'm not saying this is not the case, but we live in an age where clinical trials have to be performed to ensure that safety is of paramount importance and people who do take these so-called cannabinoids do more harm than good. I suppose this all halts back to this idea of aspirin and we talk about aspirin quite a bit. This whole idea aspirin is quite good to deviate pain, but the aspirin came from the white willow and no one suggested that we should be chewing on white willow.

Kat - I mean, the thing I understand about the original white willow compounds because then it was changed and made to be less irritating to the stomach and to be better. the cannabinoid chemicals from plants, are they actually the best drugs, the best cannabinoid drugs?

Wai - Yes. So, the difficulty is that cannabis plant itself contains quite a few - that people say, between 100 to 200 different chemicals and each one has their own activity. There's lots of data that suggest that some cannabinoids, the minor cannabinoids can actually reverse antagonise the activity of things like THC and CBD. So, what you could do by smoking cannabis or taking cannabis, the whole plant itself is to remove or reverse the actual effects that...

Kat - Counteract it. so, you're doing one good on one hand and actually, counter balancing it.

Wai - Exactly. And so, we have a situation where the patient doesn't benefit at all by taking a whole cannabis. I suppose one thing Kat, that's important to stress is that some of these cannabinoids can actually antagonise medicines that people are already taking. So, if you've got a cancer patient who's taking Cisplatin or some kind of drug, cannabis can actually antagonise that if not taken carefully.

Kat - So, if you look on social media, things like Facebook, for my day job, when I'm not doing this, I work for cancer research UK and often, we get people saying, "Weeds that cure man". If I put it to you bluntly, is cannabis the cure for cancer? What's your take on this?

Wai - Well, first of all, there's no all-out cure for cancer unfortunately, but what I can say is that these cannabinoids, these cannabis based substances can have a role to play. If used correctly and if possible, in combination with other drugs, you can actually reverse certain aspects of cancer. You probably won't cure it, but you'll go a long way in making cancer more of a chronic condition. I think you can live with and you end up dying with cancer rather than dying of cancer. I suppose that's the ultimate aim. Of course, everyone wants to cure cancer, but unfortunately, there's no one single drug that can do that.

Kat - In terms of where the research is going now, we heard from Monique that it's hard to do this kind of research. give us a picture of maybe over the next 5 years because I certainly watched with interest in America where the legislative frameworks eased up a bit. Where do you think things are going to be going? Where are the needs to research these drugs?

Wai - Sure. If we take a medicine that can treat cancer as one that can target these cell signalling pathways which I eluded to earlier, cannabinoids can do that and we have lots of data to suggest that. and if we're serious about trying to find a new medicine and to fight some forms of cancer, we really need to investigate these cannabinoids. I'm not saying we should investigate cannabis. We might investigate cannabis as a whole plant, but right now, we have certain chemicals from the plant that can work against cancer and that's something we should be doing hopefully in the next few years. We can start exploring these, what's the mechanisms, how do these drugs work, what drugs can we use this with, and essentially just to maximise the opportunities that these plants, these drugs can provide us with.

Kat -   And I guess ultimately, getting benefit to as many patients as possible through this kind of information.

Wai - Absolutely. That's the most important. Let's not forget, we're not talking, not like cannabis that's a drug that causes you these highs. We're talking about the potential of these cannabis based drugs that can help patients with cancer.

Kat - Thank you very much. That's Wai Liu from St. George's University of London.



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