IRA FLATOW, HOST:
Remember that story of the Trojan horse from Greek mythology? After a 10-year siege, the Greeks tricked the people of Troy into accepting a gift: a giant, wooden horse. What they didn't know was that Greek soldiers were hiding inside, and the troops went on to destroy the city and bring an end to the Trojan War.
Now imagine if you could do the same thing, something similar in your body, to destroy cancer cells. Researchers at Johns Hopkins School of Medicine are investigating how to turn stem cells into Trojan horses, aiming - arming them with proteins so that they can stealthily track down and destroy cancer cells that may have spread into hard-to-reach places like in your brain. And what's more, they're harvesting these stem cells from an unlikely place - human fat. Boy, could they make a lot of stem cells there.
My next guest is here to tell us more about this experiment in way to treat stem cells. Alfredo Quinones-Hinojosa is a professor of neurosurgery and oncology and director of the Brain Tumor Stem Cell Laboratory at Johns Hopkins in Baltimore. He is a lead author of a new study that was published in the Public Library of Science One. Welcome to the program.
DR. ALFREDO QUINONES-HINOJOSA: I'm delighted to be here. Thank you.
FLATOW: You're quite welcome. How do these cells act like Trojan horses?
QUINONES-HINOJOSA: Well, we make them act like Trojan horses. One of the innate abilities they have is that for some reason they just chase these very difficult-to-reach migratory cancer cells in human brain. And because of this innate ability, we can then load them with these, you know, Greek soldiers, as you said in the introduction, in this case as a way of killing brain cancer cells, and they reach, they get these cancer cells. And in our experimental studies, at least in an in-vitro study, they seem to have a very good efficacy.
FLATOW: Is this in mice? Are you doing this in mice?
QUINONES-HINOJOSA: Well, we - the paper that we publish right now is all in-vitro, and it was a proof of principle that we can get these cells from human fat. And the series of experiments that we're doing in the laboratory right now are precisely in rodents, in mice.
FLATOW: Mm-hmm. And they're able to cross that blood-brain barrier and go into the brain?
QUINONES-HINOJOSA: Yes. And this has been shown already, it's been shown with mesenchymal stem cells that are derived from bone marrow. What we did is we did the same thing with mesenchymal stem cells that are derived from fat, you know? We've done it in the laboratory, and this specific article that you're referring to, in the Public Library of Science, is that we actually were able to isolate these stem cells from our human - our patients, basically.
FLATOW: And so you were successful in treating the mice. How successful were you?
QUINONES-HINOJOSA: Well, in the paper - let me just clarify it. In our preliminary studies in the laboratory, yes, we're having a fair amount of success treating these mice and knowing that these mesenchymal stem cells from fat can actually go across the blood-brain barrier and they can actually track these cancer stem cells, brain tumor stem cells. And obviously this is all very preliminary work that we continue to do in our laboratory.
FLATOW: Uh-huh. And the idea is that we're getting closer to human cells or we're not even that far in animals yet? Do we know that they go out and destroy the brain cells - the bad cells, the tumors?
QUINONES-HINOJOSA: Well, this is a beautiful question. I would say just to be very cautious, Ira, we are not that, you know, not that far away from being able to use it in humans. But I always say, what does that mean? I would say that in my estimation, in the next five to 10 years we'll be able to hopefully bring this into human clinical trials if - with the right support, resources to be able to do the work. Right now we are at the embryonic stages of being able to do it in animals. That's exactly where we are. And obviously, as you know, like everything in science, it takes a little bit of time before we can translate it into the human brain.
FLATOW: And why fat cells?
QUINONES-HINOJOSA: Well, it turns out it was just a funny story. I came into my laboratory at Johns Hopkins one day and I saw one of my post-doctoral fellows trying to get fat from a little rodent. And because, you know, this was about five years ago because she said that she wanted to use the stem cells from fat as control for the kind of work that I do in my laboratory, which is brain cancer. And then I said, well, I get a lot of fat from my own patients because I have to use it. Sometimes I take tumors through the nose, through the base of the skull, and I have to use a little bit of fat as a cork.
And then I began to send some of the fat that otherwise was going to be thrown into the garbage into the lab, and we began to do experiments. And we began to realize that these fat cells had similar characteristics, when you make them stem cells, to the stem cells that we've been getting for years from bone marrow. And that's also been done around the world by a few selected laboratories, so I knew there was a cadre of people around the world that were doing similar work. And I got very encouraged, and this is where we are today.
FLATOW: And then, there's no shortage of fat cells, we know that, don't we?
FLATOW: Could this work for other cancers or other neurological diseases?
QUINONES-HINOJOSA: We believe so. And once again, we have to be very, very cautious. We're at the embryonic stages of understanding this. But yes, because of the same affinity that these stem cells from fat have towards brain tumors, they have towards other injuries in the brain and theoretically towards other cancers that metastasize in other parts of the body. They go where there is injury, where there is attraction towards them.
FLATOW: So they go where - they seek out an injury is what you're saying.
QUINONES-HINOJOSA: Correct. That's exactly right. I think - and you're going to ask me, so what is the mechanism? At this point, like I said, I think that a lot of laboratories around the world are trying to understand this, but we really have very, very little understanding. We just know that they're very efficient.
FLATOW: Could they attack - could they treat, let's say, damaged artery cells, I mean that are not neurological cells? Could they - could you engineer them to do that?
QUINONES-HINOJOSA: I would believe so. I mean, you're talking about making them epithelial cells or something that will actually create blood vessels. There's actually - and actually it's also a concern in cancer. If you think about it, this is one of the things that we have to be very cautious with these mesenchymal stem cells because there is a group of people who believe that these mesenchymal stem cells can also become cancerous.
In our hands, that hasn't been the experience. But you know, we have to be careful because they can actually form blood vessels and that's one of the reasons why they've been speculated they can be actually be good for diseases like stroke, you know, where you need to create blood vessels. So they're really - they have multi-potential. They have a great ability to do many things. But once again, we just have to study them very systematically.
FLATOW: Yeah. We know how difficult it is to get stuff that works in mice to work in people.
FLATOW: Yeah. So we'll have to wait to see how that happens. Thank you very much, doctor, and good luck to you.
QUINONES-HINOJOSA: Well, I'm delighted to be with you and your audience. Thank you very much.
FLATOW: You're welcome. Alfredo Quinones-Hinojosa is professor of neurosurgery and oncology, director of the Brain Tumor Stem Cell Lab at Johns Hopkins School of Medicine in Baltimore.
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