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  • It was a Sunday afternoon back in April of this year.

  • My phone was ringing,

  • I picked it up.

  • The voice said, "It's Rebecca.

  • I'm just calling to invite you

  • to my funeral."

  • I said, "Rebecca, what are you talking about?"

  • She said, "Joy, as my friend, you have to let me go.

  • It's my time."

  • The next day, she was dead.

  • Rebecca was 31 years old when she died.

  • She had an eight-year struggle with breast cancer.

  • It came back three times.

  • I failed her.

  • The scientific community failed her.

  • And the medical community failed her.

  • And she's not the only one.

  • Every five seconds,

  • someone dies of cancer.

  • Today, we medical researchers are committed

  • to having Rebecca and people like her

  • be one of the last patients that we fail.

  • The US government alone has spent over 100 billion on cancer research

  • since the 1970s,

  • with limited progress in regards to patient survival,

  • especially for certain types of very aggressive cancers.

  • So we need a change because, clearly,

  • what we've been doing so far has not been working.

  • And what we do in medicine is to send out firefighters,

  • because cancer is like a big fire.

  • And these firefighters are the cancer drugs.

  • But we're sending them out without a fire truck --

  • so without transportation, without ladders

  • and without emergency equipment.

  • And over 99 percent of these firefighters never make it to the fire.

  • Over 99 percent of cancer drugs never make it to the tumor

  • because they lack transportation and tools

  • to take them to the location they're aiming for.

  • Turns out, it really is all about location, location, location.

  • (Laughter)

  • So we need a fire truck to get to the right location.

  • And I'm here to tell you that nanoparticles are the fire trucks.

  • We can load cancer drugs inside nanoparticles,

  • and nanoparticles can function as the carrier

  • and necessary equipment

  • to bring the cancer drugs to the heart of the tumor.

  • So what are nanoparticles,

  • and what does it really mean to be nano-sized?

  • Well, there are many different types of nanoparticles

  • made out of various materials,

  • such as metal-based nanoparticles

  • or fat-based nanoparticles.

  • But to really illustrate what it means to be nano-sized,

  • I took one of my hair strands

  • and placed it under the microscope.

  • Now, I have very thin hair,

  • so my hair is approximately 40,000 nanometers in diameter.

  • So this means, if we take 400 of our nanoparticles

  • and we stack them on top of each other,

  • we get the thickness of a single hair strand.

  • I lead a nanoparticle laboratory to fight cancer and other diseases

  • at Mayo Clinic here in Jacksonville.

  • And at Mayo Clinic,

  • we really have the tools to make a difference for patients,

  • thanks to the generous donations and grants to fund our research.

  • And so, how do these nanoparticles manage to transport cancer drugs

  • to the tumor?

  • Well, they have an extensive toolbox.

  • Cancer drugs without nanoparticles are quickly washed out of the body

  • through the kidneys

  • because they're so small.

  • So it's like water going through a sieve.

  • And so they don't really have time to reach the tumor.

  • Here we see an illustration of this.

  • We have the firefighters, the cancer drugs.

  • They're circulating in the blood,

  • but they're quickly washed out of the body

  • and they don't really end up inside the tumor.

  • But if we put these cancer drugs inside nanoparticles,

  • they will not get washed out by the body

  • because the nanoparticles are too big.

  • And they will continue to circulate in the blood,

  • giving them more time to find the tumor.

  • And here we see the cancer drug, the firefighters,

  • inside the fire truck, the nanoparticles.

  • They're circulating in the blood,

  • they don't get washed out

  • and they actually end up reaching the tumor.

  • And so what other tools do nanoparticles have?

  • Well, they can protect cancer drugs from getting destroyed inside the body.

  • There are certain very important but sensitive drugs

  • that are easily degraded by enzymes in the blood.

  • So unless they have this nanoparticle protection,

  • they will not be able to function.

  • Another nanoparticle tool are these surface extensions

  • that are like tiny hands with fingers that grab on to the tumor

  • and fit exactly onto it,

  • so that when the nanoparticles are circulating,

  • they can attach onto the cancer cells,

  • buying the cancer drugs more time to do their job.

  • And these are just some of the many tools that nanoparticles can have.

  • And today,

  • we have more than 10 clinically approved nanoparticles for cancer

  • that are given to patients all over the world.

  • Yet, we have patients, like Rebecca, who die.

  • So what are the major challenges and limitations

  • with currently approved nanoparticles?

  • Well, a major challenge is the liver,

  • because the liver is the body's filtration system,

  • and the liver recognizes and destroys foreign objects,

  • such as viruses, bacteria and also nanoparticles.

  • And the immune cells in the liver eat the nanoparticles,

  • preventing them from reaching the tumor.

  • And here we see an illustration where the kidney is no longer a problem,

  • but these fire trucks, the nanoparticles,

  • get stuck in the liver

  • and, actually, less of them end up reaching the tumor.

  • So a future strategy to improve nanoparticles

  • is to temporarily disarm the immune cells in the liver.

  • So how do we disarm these cells?

  • Well, we looked at drugs that were already clinically approved

  • for other indications

  • to see if any of them could stop the immune cells

  • from eating the nanoparticles.

  • And unexpectedly, in one of our preclinical studies,

  • we found that a 70-year-old malaria drug

  • was able to stop the immune cells from internalizing the nanoparticles

  • so that they could escape the liver

  • and continue their journey to their goal, the tumor.

  • And here we see the illustration of blocking the liver.

  • The nanoparticles don't go there,

  • and they instead end up in the tumor.

  • So, sometimes, unexpected connections are made in science

  • that lead to new solutions.

  • Another strategy for preventing nanoparticles

  • from getting stuck in the liver

  • is to use the body's own nanoparticles.

  • Yes -- surprise, surprise.

  • You, and you and you, and all of us have a lot of nanoparticles

  • circulating in our bodies.

  • And because they're part of our bodies,

  • the liver is less likely to label them as foreign.

  • And these biological nanoparticles can be found in the saliva,

  • in the blood, in the urine, in pancreatic juice.

  • And we can collect them from the body

  • and use them as fire trucks for cancer drugs.

  • And in this case,

  • the immune cells in the liver are less likely to eat

  • the biological nanoparticles.

  • So we're using a Trojan-horse-based concept

  • to fool the liver.

  • And here we see the biological nanoparticles

  • circulating in the blood.

  • They don't get recognized by the liver,

  • and they end up in the tumor.

  • And in the future,

  • we want to exploit nature's own nanoparticles

  • for cancer drug delivery,

  • to reduce side effects and save lives

  • by preventing the cancer drugs from being in the wrong location.

  • However, a major problem has been:

  • How do we isolate these biological nanoparticles in large quantities

  • without damaging them?

  • My lab has developed an efficient method for doing this.

  • We can process large quantities of liquids from the body

  • to produce a highly concentrated, high-quality formulation

  • of biological nanoparticles.

  • And these nanoparticles are not yet in clinical use,

  • because it takes an average of 12 years

  • to get something from the lab

  • to your medicine cabinet.

  • And this is the type of challenge that requires teamwork

  • from scientists and physicians,

  • who dedicate their lives to this battle.

  • And we keep going, thanks to inspiration from patients.

  • And I believe that if we keep working on these nanomedicines,

  • we will be able to reduce harm to healthy organs,

  • improve quality of life

  • and save future patients.

  • I like to imagine

  • that if these treatments had been available for Rebecca,

  • that call from her

  • could have been an invitation

  • not to her funeral,

  • but her wedding.

  • Thank you.

  • (Applause)

It was a Sunday afternoon back in April of this year.

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【TED】How nanoparticles could change the way we treat cancer | Joy Wolfram

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    林宜悉   に公開 2019 年 11 月 06 日
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