0:00:00.813,0:00:04.064
This is a talk about sugar and cancer,

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and I became interested in sugar[br]when I was in college.

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Not this kind of sugar.

0:00:09.610,0:00:12.691
It was the sugar that[br]our biology professors

0:00:12.691,0:00:14.247
taught us about

0:00:14.247,0:00:17.005
in the context of the coating

0:00:17.005,0:00:18.937
of your cells,

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and maybe you didn't know

0:00:20.589,0:00:23.070
that your cells are coated with sugar.

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And I didn't know that either

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until I took these courses in college,

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but back then,

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

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people didn't know much about why

0:00:34.925,0:00:37.249
our cells are coated with sugar.

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And when I dug through my notes,

0:00:38.982,0:00:41.058
what I noticed I had written down

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is that the sugar coating on our cells

0:00:43.886,0:00:47.539
is like the sugar coating[br]on a peanut M&M.

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And people thought[br]the sugar coating on our cells

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was like a protective coating

0:00:52.960,0:00:57.204
that somehow made our cells[br]stronger or tougher.

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But we now know, many decades later,

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that it's much more complicated than that

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and that the sugars on our cells[br]are actually very complex

0:01:07.286,0:01:09.854
and if you could shrink yourself down

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to a little miniature airplane

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and fly right along[br]the surface of your cells,

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it might look something like this,

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with geographical features,

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and now the complex sugars[br]are these trees and bushes,

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weeping willows that are[br]swaying in the wind

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and moving with the waves.

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And when I started thinking about[br]all these complex sugars

0:01:33.953,0:01:36.902
that are like this foliage on our cells,

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it became one of the most[br]interesting problems that I encountered

0:01:39.943,0:01:43.990
as a biologist and also as a chemist.

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

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the surface of our cells

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as a language.

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

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But what are they trying to tell us?

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I can tell you that we do know[br]some information

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that comes from these sugars,

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and it's turned out already[br]to be incredibly important

0:02:08.591,0:02:11.040
in the world of medicine.

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For example, one thing[br]your sugars are telling us

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is your blood type.

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So your blood cells, your red blood cells

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are coated with sugars,

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and the chemical structures[br]of those sugars

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determine your blood type.

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So for example, I know[br]that I am blood type O,

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and how many people[br]are also blood type O?

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

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

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

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

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what this means is that[br]we have this chemical structure

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on the surface of our blood cells:

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

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And that, by definition, is blood type O.

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Now, how many people are blood type A?

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Right here.

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So that means you have[br]an enzyme in your cells

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that adds one more building block,

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that red sugar,

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to build a more complex structure.

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And how many people are blood type B?

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Quite a few.

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You have a slightly different[br]enzyme than the A people,

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so you build a slightly[br]different structure,

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and those of you that are AB

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have the enzyme from your mother,[br]the other enzyme from your father,

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

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And when this was figured out,

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which is now back in the previous century,

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

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which of course is the blood transfusion,

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and by knowing what your blood type is,

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we can make sure,[br]if you ever need a transfusion,

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that your donor has the same blood type

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so that your body doesn't[br]see foreign sugars

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which it wouldn't like[br]and would certainly reject.

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What else are the sugars[br]on the surface of your cells

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trying to tell us?

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Well, those sugars

0:04:03.221,0:04:06.812
might be telling us that you have cancer.

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So a few decades ago,

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correlations began to emerge[br]from the analysis

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of tumor tissue,

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and the typical scenario is a patient[br]would have a tumor detected

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and the tissue would be removed

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in a biopsy procedure

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and then sent down to a pathology lab,

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where that tissue would be analyzed

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to look for chemical changes

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that might inform the oncologist[br]about the best course of treatment.

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And what was discovered[br]from studies like that

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is that the sugars have changed

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when the cell transforms

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from being healthy to being sick.

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And those correlations

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have come up again and again and again,

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but a big question in the field

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has been why.

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

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

0:05:03.517,0:05:10.014
to be related to the disease process?

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So one of the changes that we study

0:05:13.248,0:05:17.011
is an increase

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in the density of a particular sugar

0:05:18.759,0:05:21.112
that's called sialic acid.

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And I think this is going to be

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one of the most important[br]sugars of our time,

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

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

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Those are different sugars.

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This is a kind of sugar[br]that is actually found

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

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It's actually quite common on your cells.

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But for some reason,

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cancer cells, at least in a successful,[br]progressive disease,

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they tend to have more sialic acid

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than a normal, healthy cell would have.

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And why? What does that mean?

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Well, what we've learned is that

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it has to do with your immune system.

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So let me tell you a little bit[br]about the importance

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of your immune system in cancer.

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

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

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"cancer immune therapy."

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And some of you might even know people

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

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What we now know is that[br]your immune cells,

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which are the white blood cells[br]coursing through your bloodstream,

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they protect you on a daily basis

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from things gone bad,

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including cancer.

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And so in this picture,

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those little green balls[br]are your immune cells,

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and that big pink cell is a cancer cell.

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And these immune cells, they go around

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and they taste all the cells in your body.

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That's their job.

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And most of the time,[br]the cells taste okay.

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But once in a while,[br]a cell might taste bad.

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Hopefully, that's the cancer cell,

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and when those immune cells[br]get the bad taste,

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

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So we know that.

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We also know that if you can[br]potentiate that tasting,

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

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out of a cancer cell,

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you get a better job protecting[br]yourself from cancer every day

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and maybe even curing a cancer.

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

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that are used to treat cancer patients

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that act exactly by this process.

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They activate the immune system[br]so that the immune system

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can be more vigorous[br]in protecting us from cancer.

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And in fact, one of those drugs

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may well have spared[br]President Jimmy Carter's life.

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Do you remember, President Carter

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had malignant melanoma

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that had metastasized to his brain,

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and that diagnosis is one that is[br]usually accompanied by numbers

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like "months to live."

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

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and now his melanoma[br]appears to be in remission,

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which is remarkable

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considering the situation[br]only a few years ago,

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in fact so remarkable that[br]provocative statement like this one --

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"Cancer is having a penicillin moment,"[br]people are saying

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with these new immune therapy drugs.

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

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

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and mostly losing the battle with.

0:08:35.125,0:08:37.176
So this is very exciting.

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Now what does this have to do with sugars?

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

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When an immune cell snuggles up[br]against a cancer cell

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to take a taste,

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it's looking for signs of disease,

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and if it finds those signs,

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

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But if that cancer cell

0:09:02.553,0:09:05.922
has a dense forest[br]of that sugar, sialic acid

0:09:05.922,0:09:09.872
well it starts to taste pretty good,

0:09:09.872,0:09:12.310
and there's a protein on immune cells

0:09:12.310,0:09:14.418
that grabs the sialic acid,

0:09:14.418,0:09:18.104
and if that protein[br]gets held at that synapse

0:09:18.104,0:09:21.402
between the immune cell[br]and the cancer cell,

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it puts that immune cell to sleep.

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The sialic acids are telling[br]the immune cell, "Hey,

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this cell's all right,

0:09:28.938,0:09:30.646
nothing to see here, move along.

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Look somewhere else."

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So in other words, as long as our cells

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are wearing a thick coat of sialic acid,

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they look fabulous, right?

0:09:42.219,0:09:44.707
It's amazing.

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And what if you could strip off that coat

0:09:47.884,0:09:50.320
and take that sugar away?

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Well, your immune system

0:09:53.095,0:09:57.319
might be able to see that cancer cell[br]for what it really is,

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something that needs to be destroyed.

0:10:01.066,0:10:03.839
And so this is what we're doing in my lab.

0:10:03.839,0:10:06.184
We're developing new medicines

0:10:06.184,0:10:09.503
that are basically[br]cell surface lawnmowers,

0:10:09.503,0:10:14.149
molecules that go down[br]to the surface of these cancer cells

0:10:14.149,0:10:16.801
and just cut off those sialic acids

0:10:16.801,0:10:21.042
so that the immune system

0:10:21.042,0:10:22.218
can reach its full potential

0:10:22.218,0:10:25.325
in eliminating those[br]cancer cells from our body.

0:10:25.325,0:10:28.097
So in closing,

0:10:28.097,0:10:30.273
let me just remind you again,

0:10:30.273,0:10:32.972
your cells are coated with sugars.

0:10:32.972,0:10:38.013
The sugars are telling cells[br]around that cell

0:10:38.013,0:10:40.842
whether the cell is good or bad,

0:10:40.842,0:10:43.288
and that's important because[br]our immune system needs

0:10:43.288,0:10:45.410
to leave the good cells alone.

0:10:45.410,0:10:48.379
Otherwise, we'd have autoimmune diseases.

0:10:48.379,0:10:51.648
But once in a while,[br]cancers get the ability

0:10:51.648,0:10:53.361
to express these new sugars,

0:10:53.361,0:10:56.264
and now that we understand[br]how those sugars

0:10:56.264,0:10:57.806
mesmerize the immune system,

0:10:57.806,0:11:00.249
we can come up with new medicines

0:11:00.249,0:11:02.236
to wake up those immune cells,

0:11:02.236,0:11:05.306
tell them, "Ignore[br]the sugars, eat the cell,

0:11:05.306,0:11:08.733
and have a delicious snack on cancer."

0:11:08.733,0:11:10.407
Thank you.

0:11:10.407,0:11:12.775
(Applause)