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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)
コツ:単語をクリックしてすぐ意味を調べられます!

読み込み中…

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

25 タグ追加 保存
林宜悉 2019 年 11 月 7 日 に公開
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