WEBVTT

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Cancer affects all of us,

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especially the ones that come back
over and over again.

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The highly invasive 
and drug-resistant ones,

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the ones that defy medical treatment,

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even when we throw our best drugs at them.

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Engineering at the molecular level,

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working at the smallest of scales,

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can provide exciting new ways

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to fight the most aggressive
forms of cancer.

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Cancer is a very clever disease.

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There are some forms of cancer,

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which, fortunately, we've learned
how to address relatively well

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with known and established drugs
and surgery.

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But, there's some forms of cancer
that don't respond

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to these approaches

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and the tumor survives
or comes back,

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even after an onslaught of drugs.

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We can think of these
very aggresive forms of cancer

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as kind of super villains in a comic book.

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They're clever, they're adaptable,

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and they're very good at staying alive.

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And, like most super villains
these days,

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their super powers come from
a genetic mutation.

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The genes that are modified
inside these tumor cells

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can enable and encode for new
and unimagined modes of survival,

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allowing the cancer cell
to live through

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even our best chemotherapy treatments.

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One example is a trick 
in which a gene allows a cell,

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even as the drug
approaches the cell,

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to push the drug out before the drug
can have any effect.

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Imagine the cell effectively
spits out the drug.

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This is just one example
of the many genetic tricks

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in the bag of our super villain, cancer.

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All due to mutant genes.

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So, we have a super villain
with incredible super powers

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and we need a new and 
powerful mode of attack.

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Actually, we can turn off a gene,

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the key is a set of molecules
known as siRNA.

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siRNA are short sequences
of genetic code

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that guide a cell to block
a certain gene.

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Each siRNA molecule
can turn off a specific gene

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inside the cell.

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For many years since its discovery,

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scientists have been very excited

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about how we can apply
these gene blockers in medicine.

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But, there is a problem.

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siRNA works well inside the cell.

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But if it gets exposed to the enzymes
that reside

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in our bloodstream or our tissues,

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it degrades within seconds.

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It has to be packaged, protected
through its journey through the body

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on its way to the final target
inside the cancer cell.

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So, here's our strategy:

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first, we'll dose the cancer cell
with siRNA, the gene blocker,

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and silence those survival genes,

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and they'll we'll whap it
with a chemo drug.

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But how do we carry that out?

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Using molecular engineering,

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we can actually design 
a super weapon

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that can travel through the blood stream.

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It has to be tiny enough
that it can get through the blood stream,

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it's got to be small enough
to penetrate the tumor tissue,

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and it's got to be tiny enough
to be taken up

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inside the cancer cell.

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To do this job well, it has to be
about one 100th the size

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of a human hair.

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Let's take a closer look
at how we can build this nanoparticle.

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First, let's start with 
the nanoparticle core.

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It's a tiny capsule that contains
the chemotherapy drug.

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This is the poison that will
actually end the tumor cell's life.

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Around this core, we'll wrap
a very thin,

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nanometers-thin blanket
of siRNA.

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This is our gene blocker.

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Because siRNA is strongly
negatively charged,

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we can protect it with a nice
protect layer

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of postively charged polymer.

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The two oppositely charged molecules


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stick together through charge attraction

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and that provides us with 
a protective layer

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that prevents the siRNA from
degrading in the blood stream.

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We're almost done.

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(Laughter)

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But there is one more big obstacle
we have to think about.

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In fact, it may be the biggest
obstacle of all.

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How do we deploy this super weapon?

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I mean, every good weapon
needs to be targeted,

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we have to target this super weapon
to the super villain cells

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that reside in the tumor.

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But, our bodies have a natural
immune defense system.

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Cells that reside in the blood stream

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and pick out things that don't belong

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so that it can destroy or elinate them.

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And guess that, our nanoparticle
is considered a foreign object.

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We have to sneak our nanoparticle

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past the tumor defense system,

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we have to get it past this mechanism
of getting rid of the foreign object

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by disguising it.

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So we add one more 
negatively charged layer

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around this nanoparticle,

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which serves two purposes.

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First, this outer layer is one of
the naturally charged,

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highly hydrated polysaccarides
that resides in our bodies.

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It creates a cloud of water molecules
around the nanoparticle

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that gives us 
an invisibility cloaking affect.

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This invisibility cloak allows
the nanoparticle

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to travel through the bloodstream
long and far enough

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to reach the tumor without getting
eliminated by the body.

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Second, this layer contains molecules
which bind specifically

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to our tumor's cell.

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Once bound, the cancer cell takes up
the nanoparticle

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and now we have our nanoparticle
inside the cancer cell

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and ready to deploy.

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Alright, I feel the same way,
let's go.

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(Applause)

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The siRNA is deployed first.

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It acts for hours,

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giving enough time to silence
and block those survival genes.

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We have now disabled those
genetic superpowers.

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What remains is a cancer cell
with no special defenses.

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Then, the chemotherapy drug
comes out of the core

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and destroys the tumor cell
cleanly and efficiently.

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With sufficient gene blockers,

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we can address many different kinds 
of mutations.

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Allowing the chance to sweep out tumors,
without leaving behind any bad guys.

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So, how does our strategy work?

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We've tested these
nanostructure particles in animals

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using a highly aggresive form
of triple negative breast cancer.

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This triple negative breast cancer
exhibits the gene

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that spits out cancer drugs
as soon as its delivered.

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Usually, doxorubicin, 
let's call it dox,

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is the cancer drug that is 
the first line of treatment

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for breast cancer.

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So, we first treated our animals
with a dox core, dox only.

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The tumor slowed their rate of growth,

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but they still grew rapidly,

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doubling in size 
over a period of two weeks.

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Then, we tried our 
combination super weapon.

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And now layer a particle
with siRNA against the chemo pump,

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plus, we have the dox in the core.

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And look, we found that not only
did the tumors stop growing,

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they actually decerased in size

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and were elimintaed 
in some cases.

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The tumors were actually
regressing.

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(Applause)

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What's great about this approach
is that it can be personalized,

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we can add many different layers
of siRNA

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to address different mutations
and tumor defense mechanisms

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and we can put different drugs
into the nanoparticle core.

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As doctors learn how to test patients


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and understand 
certain tumor genetic types,

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they can help us determine
which patients

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can benefit from this strategy

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and which gene blockers we can use.

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Ovarian cancer strikes 
a special chord with me.

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It is a very aggresive cancer,

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in part because it's discovered
at very late stages

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when its highly advanced

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and there are a number 
of genetic mutations.

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After the first round of chemotherapy,

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this cancer comes back
for 75 percent of patients.

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And it usually comes back
in a drug resistant form.

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High-grade ovarian cancer


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is one of the biggest 
super villains out there.

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And we're now directlng
our super weapon

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towards its defeat.

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As a researcher,

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I usually don't get to work with patients.

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But I recently met a mother

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who is an ovarian cancer survivor,
Mimi, and her daughter Paige.

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I was deeply inspired

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by the optimism and strength

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that both mother and daughter displayed

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and by their story of courage and support.

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At this event, we spoke about
the different technologies

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directed at cancer.

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And Mimi was in tears
as she explained how

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learning about these efforts

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gives her hope for future generations,

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including her own daughter.

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This really touched me.

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It's not just about building
really elegant science,

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it's about changing people's lives.

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It's about understanding the power
of engineering

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on the scale of molecules.

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I know that as students like Paige

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move forward in their careers,

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they'll open new possibilites

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in addressing some of the big 
health problems in the world,

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including, ovarian cancer,
neurological disorders,

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infectious disease.

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Just as chemical engineering
has found a way

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to open doors for me.

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Has provided a way of engineering
on the tiniest scale,

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that of molecules

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to heal on the human scale.

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Thank you

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(Applause)