WEBVTT 00:00:00.669 --> 00:00:03.444 This is a talk about sugar and cancer. 00:00:03.889 --> 00:00:07.166 I became interested in sugar when I was in college. 00:00:07.190 --> 00:00:09.042 Not this kind of sugar. 00:00:09.066 --> 00:00:14.017 It was the sugar that our biology professors taught us about 00:00:14.041 --> 00:00:18.183 in the context of the coating of your cells. 00:00:18.733 --> 00:00:22.843 Maybe you didn't know that your cells are coated with sugar. 00:00:22.867 --> 00:00:24.442 And I didn't know that, either, 00:00:24.466 --> 00:00:26.621 until I took these courses in college, 00:00:26.645 --> 00:00:28.057 but back then -- 00:00:28.081 --> 00:00:31.640 and this was in, let's just call it the 1980s -- 00:00:32.560 --> 00:00:36.814 people didn't know much about why our cells are coated with sugar. 00:00:36.838 --> 00:00:40.805 And when I dug through my notes, what I noticed I had written down 00:00:40.829 --> 00:00:45.374 is that the sugar coating on our cells is like the sugar coating 00:00:45.398 --> 00:00:46.604 on a peanut M and M. 00:00:47.198 --> 00:00:50.864 And people thought the sugar coating on our cells 00:00:50.888 --> 00:00:52.718 was like a protective coating 00:00:52.742 --> 00:00:55.993 that somehow made our cells stronger or tougher. NOTE Paragraph 00:00:56.934 --> 00:00:59.060 But we now know, many decades later, 00:00:59.084 --> 00:01:01.360 that it's much more complicated than that, 00:01:01.906 --> 00:01:06.367 and that the sugars on our cells are actually very complex. 00:01:07.183 --> 00:01:12.695 And if you could shrink yourself down to a little miniature airplane 00:01:12.719 --> 00:01:16.501 and fly right along the surface of your cells, 00:01:16.525 --> 00:01:18.891 it might look something like this -- 00:01:18.915 --> 00:01:21.116 with geographical features. 00:01:21.140 --> 00:01:25.170 And now, the complex sugars are these trees and bushes -- 00:01:25.194 --> 00:01:27.726 weeping willows that are swaying in the wind 00:01:27.750 --> 00:01:29.787 and moving with the waves. 00:01:29.811 --> 00:01:33.624 And when I started thinking about all these complex sugars 00:01:33.648 --> 00:01:36.574 that are like this foliage on our cells, 00:01:36.598 --> 00:01:39.715 it became one of the most interesting problems that I encountered 00:01:39.739 --> 00:01:42.743 as a biologist and also as a chemist. 00:01:43.657 --> 00:01:46.592 And so now we tend to think about the sugars 00:01:46.616 --> 00:01:49.884 that are populating the surface of our cells 00:01:49.908 --> 00:01:51.703 as a language. 00:01:52.342 --> 00:01:56.223 They have a lot of information stored in their complex structures. NOTE Paragraph 00:01:57.142 --> 00:01:59.711 But what are they trying to tell us? 00:02:00.548 --> 00:02:03.863 I can tell you that we do know some information 00:02:03.887 --> 00:02:05.492 that comes from these sugars, 00:02:05.516 --> 00:02:08.451 and it's turned out already to be incredibly important 00:02:08.475 --> 00:02:10.295 in the world of medicine. NOTE Paragraph 00:02:10.777 --> 00:02:14.438 For example, one thing your sugars are telling us 00:02:14.462 --> 00:02:15.919 is your blood type. 00:02:17.041 --> 00:02:21.195 So your blood cells, your red blood cells, are coated with sugars, 00:02:21.219 --> 00:02:25.896 and the chemical structures of those sugars determine your blood type. 00:02:25.920 --> 00:02:29.843 So for example, I know that I am blood type O. 00:02:29.867 --> 00:02:32.978 How many people are also blood type O? 00:02:33.002 --> 00:02:34.160 Put your hands up. 00:02:34.184 --> 00:02:35.377 It's a pretty common one, 00:02:35.401 --> 00:02:38.336 so when so few hands go up, either you're not paying attention 00:02:38.360 --> 00:02:41.250 or you don't know your blood type, and both of those are bad. NOTE Paragraph 00:02:41.274 --> 00:02:42.289 (Laughter) NOTE Paragraph 00:02:42.313 --> 00:02:44.976 But for those of you who share the blood type O with me, 00:02:45.000 --> 00:02:47.715 what this means is that we have this chemical structure 00:02:47.739 --> 00:02:49.777 on the surface of our blood cells: 00:02:50.296 --> 00:02:54.019 three simple sugars linked together to make a more complex sugar. 00:02:54.043 --> 00:02:56.311 And that, by definition, is blood type O. NOTE Paragraph 00:02:57.366 --> 00:02:59.496 Now, how many people are blood type A? 00:03:00.574 --> 00:03:01.743 Right here. 00:03:01.767 --> 00:03:04.728 That means you have an enzyme in your cells 00:03:04.752 --> 00:03:07.168 that adds one more building block, 00:03:07.192 --> 00:03:08.567 that red sugar, 00:03:08.591 --> 00:03:10.415 to build a more complex structure. 00:03:11.116 --> 00:03:13.506 And how many people are blood type B? 00:03:14.298 --> 00:03:15.463 Quite a few. 00:03:15.487 --> 00:03:18.215 You have a slightly different enzyme than the A people, 00:03:18.239 --> 00:03:20.355 so you build a slightly different structure, 00:03:20.379 --> 00:03:22.492 and those of you that are AB 00:03:22.516 --> 00:03:25.708 have the enzyme from your mother, the other enzyme from your father, 00:03:25.732 --> 00:03:29.507 and now you make both of these structures in roughly equal proportions. 00:03:29.531 --> 00:03:31.935 And when this was figured out, 00:03:31.959 --> 00:03:34.697 which is now back in the previous century, 00:03:34.721 --> 00:03:38.238 this enabled one of the most important medical procedures in the world, 00:03:38.262 --> 00:03:40.640 which, of course, is the blood transfusion. 00:03:40.664 --> 00:03:42.560 And by knowing what your blood type is, 00:03:42.584 --> 00:03:45.176 we can make sure, if you ever need a transfusion, 00:03:45.200 --> 00:03:47.721 that your donor has the same blood type, 00:03:47.745 --> 00:03:51.066 so that your body doesn't see foreign sugars, 00:03:51.783 --> 00:03:54.220 which it wouldn't like and would certainly reject. NOTE Paragraph 00:03:56.113 --> 00:04:00.355 What else are the sugars on the surface of your cells trying to tell us? 00:04:01.112 --> 00:04:05.805 Well, those sugars might be telling us that you have cancer. 00:04:06.708 --> 00:04:08.960 So a few decades ago, 00:04:08.984 --> 00:04:14.377 correlations began to emerge from the analysis of tumor tissue. 00:04:14.401 --> 00:04:18.912 And the typical scenario is a patient would have a tumor detected, 00:04:18.936 --> 00:04:22.764 and the tissue would be removed in a biopsy procedure 00:04:22.788 --> 00:04:25.558 and then sent down to a pathology lab 00:04:25.582 --> 00:04:29.713 where that tissue would be analyzed to look for chemical changes 00:04:29.737 --> 00:04:34.451 that might inform the oncologist about the best course of treatment. 00:04:34.979 --> 00:04:37.863 And what was discovered from studies like that 00:04:37.887 --> 00:04:40.751 is that the sugars have changed 00:04:40.775 --> 00:04:45.772 when the cell transforms from being healthy to being sick. 00:04:46.823 --> 00:04:51.806 And those correlations have come up again and again and again. 00:04:52.497 --> 00:04:56.963 But a big question in the field has been: Why? 00:04:56.987 --> 00:05:01.231 Why do cancers have different sugars? What's the importance of that? 00:05:01.255 --> 00:05:04.616 Why does it happen, and what can we do about it if it does turn out 00:05:04.640 --> 00:05:08.395 to be related to the disease process? NOTE Paragraph 00:05:09.783 --> 00:05:12.994 So, one of the changes that we study 00:05:13.018 --> 00:05:18.563 is an increase in the density of a particular sugar 00:05:18.587 --> 00:05:20.916 that's called sialic acid. 00:05:21.617 --> 00:05:25.541 And I think this is going to be one of the most important sugars 00:05:25.565 --> 00:05:26.723 of our times, 00:05:26.747 --> 00:05:30.822 so I would encourage everybody to get familiar with this word. 00:05:31.502 --> 00:05:34.467 Sialic acid is not the kind of sugar that we eat. 00:05:34.491 --> 00:05:36.047 Those are different sugars. 00:05:36.602 --> 00:05:39.566 This is a kind of sugar that is actually found 00:05:39.590 --> 00:05:42.718 at certain levels on all of the cells in your body. 00:05:42.742 --> 00:05:45.610 It's actually quite common on your cells. 00:05:46.393 --> 00:05:47.704 But for some reason, 00:05:48.451 --> 00:05:53.939 cancer cells, at least in a successful, progressive disease, 00:05:53.963 --> 00:05:57.072 tend to have more sialic acid 00:05:57.096 --> 00:05:59.443 than a normal, healthy cell would have. 00:05:59.467 --> 00:06:00.909 And why? 00:06:00.933 --> 00:06:02.179 What does that mean? 00:06:03.276 --> 00:06:04.728 Well, what we've learned 00:06:04.752 --> 00:06:08.227 is that it has to do with your immune system. NOTE Paragraph 00:06:08.935 --> 00:06:12.501 So let me tell you a little bit about the importance of your immune system 00:06:12.525 --> 00:06:13.689 in cancer. 00:06:13.713 --> 00:06:17.231 And this is something that's, I think, in the news a lot these days. 00:06:17.255 --> 00:06:20.161 You know, people are starting to become familiar with the term 00:06:20.185 --> 00:06:22.947 "cancer immune therapy." 00:06:22.971 --> 00:06:24.782 And some of you might even know people 00:06:24.806 --> 00:06:28.713 who are benefiting from these very new ways of treating cancer. 00:06:29.848 --> 00:06:33.089 What we now know is that your immune cells, 00:06:33.113 --> 00:06:37.047 which are the white blood cells coursing through your bloodstream, 00:06:37.071 --> 00:06:41.727 protect you on a daily basis from things gone bad -- 00:06:41.751 --> 00:06:43.092 including cancer. 00:06:43.951 --> 00:06:45.942 And so in this picture, 00:06:45.966 --> 00:06:48.687 those little green balls are your immune cells, 00:06:48.711 --> 00:06:51.659 and that big pink cell is a cancer cell. 00:06:52.250 --> 00:06:57.015 And these immune cells go around and taste all the cells in your body. 00:06:57.039 --> 00:06:58.334 That's their job. 00:06:58.913 --> 00:07:01.668 And most of the time, the cells taste OK. NOTE Paragraph 00:07:01.692 --> 00:07:04.196 But once in a while, a cell might taste bad. 00:07:04.744 --> 00:07:06.555 Hopefully, that's the cancer cell, 00:07:06.579 --> 00:07:08.962 and when those immune cells get the bad taste, 00:07:08.986 --> 00:07:11.795 they launch an all-out strike and kill those cells. 00:07:12.630 --> 00:07:13.783 So we know that. 00:07:13.807 --> 00:07:18.223 We also know that if you can potentiate that tasting, 00:07:18.247 --> 00:07:22.075 if you can encourage those immune cells to actually take a big old bite 00:07:22.099 --> 00:07:23.342 out of a cancer cell, 00:07:23.366 --> 00:07:26.957 you get a better job protecting yourself from cancer every day 00:07:26.981 --> 00:07:28.713 and maybe even curing a cancer. 00:07:29.509 --> 00:07:32.355 And there are now a couple of drugs out there in the market 00:07:32.379 --> 00:07:34.450 that are used to treat cancer patients 00:07:34.474 --> 00:07:37.215 that act exactly by this process. 00:07:37.726 --> 00:07:39.355 They activate the immune system 00:07:39.379 --> 00:07:42.126 so that the immune system can be more vigorous 00:07:42.150 --> 00:07:43.902 in protecting us from cancer. NOTE Paragraph 00:07:43.926 --> 00:07:45.969 In fact, one of those drugs 00:07:45.993 --> 00:07:48.983 may well have spared President Jimmy Carter's life. 00:07:49.516 --> 00:07:53.996 Do you remember, President Carter had malignant melanoma 00:07:54.020 --> 00:07:56.878 that had metastasized to his brain, 00:07:56.902 --> 00:08:00.256 and that diagnosis is one that is usually accompanied by numbers 00:08:00.280 --> 00:08:02.125 like "months to live." 00:08:03.093 --> 00:08:07.488 But he was treated with one of these new immune-stimulating drugs, 00:08:07.512 --> 00:08:10.871 and now his melanoma appears to be in remission, 00:08:10.895 --> 00:08:12.536 which is remarkable, 00:08:12.560 --> 00:08:16.001 considering the situation only a few years ago. 00:08:16.025 --> 00:08:17.845 In fact, it's so remarkable 00:08:17.869 --> 00:08:20.669 that provocative statements like this one: 00:08:20.693 --> 00:08:24.408 "Cancer is having a penicillin moment," people are saying, 00:08:24.432 --> 00:08:26.253 with these new immune therapy drugs. 00:08:26.277 --> 00:08:29.475 I mean, that's an incredibly bold thing to say about a disease 00:08:29.499 --> 00:08:32.148 which we've been fighting for a long time 00:08:32.172 --> 00:08:34.252 and mostly losing the battle with. 00:08:34.855 --> 00:08:36.384 So this is very exciting. NOTE Paragraph 00:08:36.907 --> 00:08:39.319 Now what does this have to do with sugars? 00:08:39.343 --> 00:08:42.063 Well, I'll tell you what we've learned. 00:08:42.944 --> 00:08:49.280 When an immune cell snuggles up against a cancer cell to take a taste, 00:08:49.304 --> 00:08:51.953 it's looking for signs of disease, 00:08:51.977 --> 00:08:53.896 and if it finds those signs, 00:08:53.920 --> 00:08:58.166 the cell gets activated and it launches a missile strike and kills the cell. 00:08:59.269 --> 00:09:05.079 But if that cancer cell has a dense forest of that sugar, sialic acid, 00:09:05.731 --> 00:09:08.699 well, it starts to taste pretty good. 00:09:09.507 --> 00:09:14.151 And there's a protein on immune cells that grabs the sialic acid, 00:09:14.175 --> 00:09:17.976 and if that protein gets held at that synapse 00:09:18.000 --> 00:09:20.424 between the immune cell and the cancer cell, 00:09:21.171 --> 00:09:23.156 it puts that immune cell to sleep. 00:09:23.809 --> 00:09:27.111 The sialic acids are telling the immune cell, 00:09:27.135 --> 00:09:30.336 "Hey, this cell's all right. Nothing to see here, move along. 00:09:30.360 --> 00:09:31.854 Look somewhere else." 00:09:32.741 --> 00:09:33.963 So in other words, 00:09:33.987 --> 00:09:38.731 as long as our cells are wearing a thick coat of sialic acid, 00:09:39.399 --> 00:09:41.417 they look fabulous, right? 00:09:42.036 --> 00:09:43.388 It's amazing. 00:09:44.524 --> 00:09:47.678 And what if you could strip off that coat 00:09:47.702 --> 00:09:50.000 and take that sugar away? 00:09:50.024 --> 00:09:53.023 Well, your immune system 00:09:53.047 --> 00:09:57.248 might be able to see that cancer cell for what it really is: 00:09:57.272 --> 00:09:59.496 something that needs to be destroyed. NOTE Paragraph 00:10:00.875 --> 00:10:03.186 And so this is what we're doing in my lab. 00:10:03.704 --> 00:10:06.026 We're developing new medicines 00:10:06.050 --> 00:10:09.107 that are basically cell-surface lawnmowers -- 00:10:09.861 --> 00:10:13.514 molecules that go down to the surface of these cancer cells 00:10:13.538 --> 00:10:16.403 and just cut off those sialic acids, 00:10:16.427 --> 00:10:20.732 so that the immune system can reach its full potential 00:10:20.756 --> 00:10:23.413 in eliminating those cancer cells from our body. NOTE Paragraph 00:10:24.983 --> 00:10:27.114 So in closing, 00:10:27.819 --> 00:10:29.972 let me just remind you again: 00:10:29.996 --> 00:10:32.263 your cells are coated with sugars. 00:10:32.972 --> 00:10:37.667 The sugars are telling cells around that cell 00:10:37.691 --> 00:10:39.611 whether the cell is good or bad. 00:10:40.682 --> 00:10:41.847 And that's important, 00:10:41.871 --> 00:10:44.927 because our immune system needs to leave the good cells alone. 00:10:44.951 --> 00:10:47.421 Otherwise, we'd have autoimmune diseases. 00:10:48.315 --> 00:10:51.463 But once in a while, cancers get the ability 00:10:51.487 --> 00:10:53.043 to express these new sugars. 00:10:53.067 --> 00:10:54.399 And now that we understand 00:10:54.423 --> 00:10:57.583 how those sugars mesmerize the immune system, 00:10:57.607 --> 00:11:01.792 we can come up with new medicines to wake up those immune cells, 00:11:01.816 --> 00:11:05.043 tell them, "Ignore the sugars, eat the cell 00:11:05.067 --> 00:11:07.650 and have a delicious snack, on cancer." NOTE Paragraph 00:11:08.574 --> 00:11:09.737 Thank you. NOTE Paragraph 00:11:10.073 --> 00:11:12.441 (Applause)