What the sugar coating on your cells is trying to tell you

This is a talk about sugar and cancer,

and I became interested in sugar
when I was in college.

Not this kind of sugar.

It was the sugar that
our biology professors

taught us about

in the context of the coating

of your cells,

and maybe you didn't know

that your cells are coated with sugar.

And I didn't know that either

until I took these courses in college,

but back then,

and this was in, let's just
call it the 1980s,

people didn't know much about why

our cells are coated with sugar.

And when I dug through my notes,

what I noticed I had written down

is that the sugar coating on our cells

is like the sugar coating
on a peanut M&M.

And people thought
the sugar coating on our cells

was like a protective coating

that somehow made our cells
stronger or tougher.

But we now know, many decades later,

that it's much more complicated than that

and that the sugars on our cells
are actually very complex

and if you could shrink yourself down

to a little miniature airplane

and fly right along
the surface of your cells,

it might look something like this,

with geographical features,

and now the complex sugars
are these trees and bushes,

weeping willows that are
swaying in the wind

and moving with the waves.

And when I started thinking about
all these complex sugars

that are like this foliage on our cells,

it became one of the most
interesting problems that I encountered

as a biologist and also as a chemist.

And so now we tend to think about
the sugars that are populating

the surface of our cells

as a language.

They have a lot of information
stored in their complex structures.

But what are they trying to tell us?

I can tell you that we do know
some information

that comes from these sugars,

and it's turned out already
to be incredibly important

in the world of medicine.

For example, one thing
your sugars are telling us

is your blood type.

So your blood cells, your red blood cells

are coated with sugars,

and the chemical structures
of those sugars

determine your blood type.

So for example, I know
that I am blood type O,

and how many people
are also blood type O?

Put your hands up.
It's a pretty common one,

and so when so few hands go up,
either you're not paying attention

or you don't know your blood type,
and both of those are bad, okay?

But for those of you who share
the blood type O with me,

what this means is that
we have this chemical structure

on the surface of our blood cells:

three simple sugars linked together
to make a more complex sugar.

And that, by definition, is blood type O.

Now, how many people are blood type A?

Right here.

So that means you have
an enzyme in your cells

that adds one more building block,

that red sugar,

to build a more complex structure.

And how many people are blood type B?

Quite a few.

You have a slightly different
enzyme than the A people,

so you build a slightly
different structure,

and those of you that are AB

have the enzyme from your mother,
the other enzyme from your father,

and now you make both of these structures
in roughly equal proportions.

And when this was figured out,

which is now back in the previous century,

this enabled one of the most
important medical procedures in the world,

which of course is the blood transfusion,

and by knowing what your blood type is,

we can make sure,
if you ever need a transfusion,

that your donor has the same blood type

so that your body doesn't
see foreign sugars

which it wouldn't like
and would certainly reject.

What else are the sugars
on the surface of your cells

trying to tell us?

Well, those sugars

might be telling us that you have cancer.

So a few decades ago,

correlations began to emerge
from the analysis

of tumor tissue,

and the typical scenario is a patient
would have a tumor detected

and the tissue would be removed

in a biopsy procedure

and then sent down to a pathology lab,

where that tissue would be analyzed

to look for chemical changes

that might inform the oncologist
about the best course of treatment.

And what was discovered
from studies like that

is that the sugars have changed

when the cell transforms

from being healthy to being sick.

And those correlations

have come up again and again and again,

but a big question in the field

has been why.

Why do cancers have different sugars?
What's the importance of that?

Why does it happen, and what
can we do about it if it does turn out

to be related to the disease process?

So one of the changes that we study

is an increase

in the density of a particular sugar

that's called sialic acid.

And I think this is going to be

one of the most important
sugars of our time,

so I would encourage everybody
to get familiar with this word.

Sialic acid is not the kind
of sugar that we eat.

Those are different sugars.

This is a kind of sugar
that is actually found

at certain levels on all
of the cells in your body.

It's actually quite common on your cells.

But for some reason,

cancer cells, at least in a successful,
progressive disease,

they tend to have more sialic acid

than a normal, healthy cell would have.

And why? What does that mean?

Well, what we've learned is that

it has to do with your immune system.

So let me tell you a little bit
about the importance

of your immune system in cancer.

And this is something that's
I think in the news a lot these days.

You know, people are starting
to become familiar with the term

"cancer immune therapy."

And some of you might even know people

who are benefiting from these
very new ways of treating cancer.

What we now know is that
your immune cells,

which are the white blood cells
coursing through your bloodstream,

they protect you on a daily basis

from things gone bad,

including cancer.

And so in this picture,

those little green balls
are your immune cells,

and that big pink cell is a cancer cell.

And these immune cells, they go around

and they taste all the cells in your body.

That's their job.

And most of the time,
the cells taste okay.

But once in a while,
a cell might taste bad.

Hopefully, that's the cancer cell,

and when those immune cells
get the bad taste,

they launch an all-out strike
and they kill those cells.

So we know that.

We also know that if you can
potentiate that tasting,

if you can encourage those immune cells
to actually take a big old bite

out of a cancer cell,

you get a better job protecting
yourself from cancer every day

and maybe even curing a cancer.

And there are now a couple of drugs
out there in the market

that are used to treat cancer patients

that act exactly by this process.

They activate the immune system
so that the immune system

can be more vigorous
in protecting us from cancer.

And in fact, one of those drugs

may well have spared
President Jimmy Carter's life.

Do you remember, President Carter

had malignant melanoma

that had metastasized to his brain,

and that diagnosis is one that is
usually accompanied by numbers

like "months to live."

But he was treated with one
of these new immune-stimulating drugs,

and now his melanoma
appears to be in remission,

which is remarkable

considering the situation
only a few years ago,

in fact so remarkable that
provocative statement like this one --

"Cancer is having a penicillin moment,"
people are saying

with these new immune therapy drugs.

I mean, that's an incredibly
bold thing to say

about a disease which we've
been fighting for a long time

and mostly losing the battle with.

So this is very exciting.

Now what does this have to do with sugars?

Well, I'll tell you what we've learned.

When an immune cell snuggles up
against a cancer cell

to take a taste,

it's looking for signs of disease,

and if it finds those signs,

the cell gets activated and it launches
a missile strike and kills the cell.

But if that cancer cell

has a dense forest
of that sugar, sialic acid

well it starts to taste pretty good,

and there's a protein on immune cells

that grabs the sialic acid,

and if that protein
gets held at that synapse

between the immune cell
and the cancer cell,

it puts that immune cell to sleep.

The sialic acids are telling
the immune cell, "Hey,

this cell's all right,

nothing to see here, move along.

Look somewhere else."

So in other words, as long as our cells

are wearing a thick coat of sialic acid,

they look fabulous, right?

It's amazing.

And what if you could strip off that coat

and take that sugar away?

Well, your immune system

might be able to see that cancer cell
for what it really is,

something that needs to be destroyed.

And so this is what we're doing in my lab.

We're developing new medicines

that are basically
cell surface lawnmowers,

molecules that go down
to the surface of these cancer cells

and just cut off those sialic acids

so that the immune system

can reach its full potential

in eliminating those
cancer cells from our body.

So in closing,

let me just remind you again,

your cells are coated with sugars.

The sugars are telling cells
around that cell

whether the cell is good or bad,

and that's important because
our immune system needs

to leave the good cells alone.

Otherwise, we'd have autoimmune diseases.

But once in a while,
cancers get the ability

to express these new sugars,

and now that we understand
how those sugars

mesmerize the immune system,

we can come up with new medicines

to wake up those immune cells,

tell them, "Ignore
the sugars, eat the cell,

and have a delicious snack on cancer."

Thank you.

(Applause)