When bees sting, they pump poison into their victims. Now researchers at Washington University School of Medicine in St. Louis have harnessed the toxin in bee venom to kill tumor cells. The researchers attached the major component of bee venom to nano-sized spheres that they call nanobees. In mice, nanobees are able to deliver the bee toxin to tumors while protecting other tissues from the toxin’s destructive power. Mouse tumors stopped growing or even shrank, and the researchers say if a similar strategy worked for humans, it may be possible to deliver cancer chemotherapy more effectively, destroying tumors while preserving healthy tissue.
BEE VENOM CONTAINS TOXINS THAT CAN FIGHT INFECTION AND KILL CANCEROUS TUMORS. THE PROBLEM, UNTIL RECENTLY, HAS INVOLVED HOW TO GET TOXINS TO TUMORS WITHOUT KILLING PATIENTS. NOW, WORKING IN MICE, WASHINGTON UNIVERSITY RESEARCHERS MAY HAVE FOUND A SOLUTION: NANOBEES. JIM DRYDEN HAS MORE
NANOBEES ARE ONE OF THE LATEST VARIATIONS OF NANOPARTICLES, MICROSCOPIC SPHERES THAT CAN DELIVER DRUGS AND IMAGING AGENTS TO TUMORS, CARDIAC BLOCKAGES AND OTHER SICK PARTS OF THE BODY. IN THE CASE OF CANCER THERAPY, THE IDEA IS TO DELIVER CANCER DRUGS TO KILL TUMOR CELLS, WHILE PRESERVING HEALTHY TISSUE THAT SURROUNDS TUMORS, ACCORDING TO WASHINGTON UNIVERSITY RESEARCHER SAMUEL WICKLINE. HE SAYS TINY NANOPARTICLES ALLOW THAT TO HAPPEN.
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The point is to include them on a nanoparticle, which is a small
carrier of drugs that will deliver them like the Post Office
directly to the appropriate address.
WICKLINE SAYS IN RECENT EXPERIMENTS, HE AND HIS COLLEAGUES DELIVERED A TOXIN FROM BEE VENOM, CALLED MELITTIN, IN MICROSCOPIC NANOPARTICLES, TO TUMOR CELLS IN MICE. WHEN MELITTIN IS ATTACHED TO NANOPARTICLES, THE RESEARCHERS CALL THOSE STRUCTURES NANOBEES. WICKLINE SAYS SCIENTISTS HAVE KNOWN FOR SOME TIME THAT MELITTIN COULD KILL CANCER CELLS, BUT IT HAS BEEN VIRUTALLY IMPOSSIBLE TO SAFELY DELIVER THE TOXIN.
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It now can be put onto one of these little particle carriers,
where it is safely conveyed in the bloodstream to the tumor,
without harming other tissues. And so weve basically replicated
what the bee is able to do, by carrying this toxin. And we know
how to make this in the laboratory, and so we dont have to ask
bees to make it. So when we make it, we can then make it and
include it in our nanoparticles as a therapeutic agent.
CANCER CHEMOTHERAPY OFTEN INVOLVES THE INFUSION OF INTRAVENOUS DRUGS THAT KILL TUMOR CELLS, BUT THOSE DRUGS ALSO CAN KILL HEALTHY TISSUE. IN THE CASE OF THIS BEE VENOM TOXIN, WICKLINE SAY INTRAVENOUS DELIVERY OF THE TOXIN WOULD RESULT IN WIDESPREAD DESTRUCTION OF RED BLOOD CELLS. BUT IN MICE, WICKLINE AND COLLEAGUES WERE ABLE TO DELIVER LOTS OF THE TOXIN WITHOUT CAUSING TOXIC SIDE EFFECTS.
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We delivered about four times the dose that would normally
kill a small animal, without having any toxic side effects
at all, and so the real promise of this delivery system is
that, not only does it make the drug able to go to the site
where its supposed to be active, but it protects the other
tissues against harmful side effects to an incredible extent,
in fact. So much so that you could use four times the lethal
dose and have absolutely no side effects.
BUT THE NANOBEES DID HAVE THE DESIRED EFFECT. TUMORS STOPPED GROWING AND EVEN GOT SMALLER. WICKLINE SAYS THE TOXIN MAY KILL MANY DIFFERENT TYPES OF TUMOR CELLS BECAUSE IT DOESNT NEED TO BIND TO SPECIFIC RECEPTORS ON PARTICULAR TUMORS AS MANY OTHER CHEMOTHERAPY AGENTS DO.
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It doesnt rely on specific binding at specific sites,
but once it gets there, it can then kill the cancer cell,
generically, by just poking a hole in it. And so, as long
as its able to be delivered to a cell, it would be useful
for many different kinds of cancers.
WICKLINES TEAM REPORTED ITS FINDINGS IN THE JOURNAL OF CLINICAL INVESTIGATION. IM JIM DRYDEN