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← The power of venom -- and how it could one day save your life

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Showing Revision 7 created 10/29/2020 by marialadias.

  1. How does a sea snail catch a fish?
  2. I mean, it's a snail, so it's slow,
  3. and the fish is not.
  4. But yet, this happens.
  5. Hidden under the sand is a cone snail.

  6. And that orange thing you see
    is kind of like a tongue.
  7. We call it a proboscis.
  8. It uses that to track and subdue
    this unsuspecting fish.
  9. In this predator-prey interaction,
  10. these are clearly not
    your garden variety escargots.
  11. These are assassins of the sea.
  12. And their weapon of choice is venom.
  13. Venom, like the venom you find
    in venomous snakes and scorpions,
  14. these sea snails, they use their venom
    to subdue fish, worms
  15. and other snails.
  16. And the venom of these snails,

  17. it's not just one thing,
  18. it's actually a cocktail
    of toxic molecules
  19. that are packaged and delivered
    through a false tooth called a radula.
  20. You can think of the radulas
    as hypodermic needles.
  21. Now, no need to worry,
  22. these snails are practicing
    good needle habits,
  23. because each radula is only used once.
  24. Now from your own knowledge
    about venomous organisms,

  25. and the keep-you-up-at-night
    fish-killing video that I just showed you,
  26. you might think that venom
    is dangerous and all bad.
  27. Well, yes and no.
  28. A more accurate way of thinking of venom
  29. is to think of it as both
    a supervillain and a superhero.
  30. In my lab, we study the evolution
    of venom in these sea snails

  31. as a force for good.
  32. Sounds like a stretch,
  33. or maybe even snake oil,
  34. but actually,
  35. while there are snakes involved,
    the product is legit.
  36. One reason the venom product
    is so successful
  37. is that it transforms a physical warfare
    into a biochemical one.
  38. Where usually the predator-prey
    interaction is one of brute force,
  39. venom takes it to a molecular scale.
  40. And it's not size that matters,
  41. but the mixture of your venom arsenal.
  42. The chemistry of the toxins
    in your arsenal
  43. is what's going to enable David
    to conquer Goliath.
  44. And in our scenario,
    David is clearly the snail.
  45. Another feature of venom
    that makes it so successful

  46. is that the toxins work
    with the precision of a Swiss Army knife.
  47. And so these toxins,
  48. they come for strongholds
    that help an organism to function.
  49. So they target blood, brain and membranes.
  50. Whether it's snail venom or snake venom,
  51. they each have components
    that can do things
  52. like cause your blood to clot,
  53. what we call "hemotoxic."
  54. Or they cause neurons in your brains
    to not function normally,
  55. what we call "neurotoxic."
  56. Or they have toxins that will poke holes
    into the membranes of your cells,
  57. causing them to rupture
    and, basically, explode,
  58. what we call "cytotoxic."
  59. Cellular explosion, people.
  60. Now, if that is not all powerful
    and all present,
  61. nothing is.
  62. Now a little about me,

  63. and why I'm so obsessed with venom.
  64. I grew up in New York City
  65. with forced access
    to the Natural History Museum.
  66. I say "forced access,"
  67. because I'm one of five kids,
  68. and my parents used museums
    as a form of childcare.
  69. There were two rules:
  70. Don't lose anybody
  71. and meet Mom and Dad
    at the African elephants
  72. at 5:30, when the museum closes.
  73. Those totally unsupervised days
    running through the halls of the museum
  74. were full of adventure and exploration.
  75. And that's how I feel
    when I'm studying venom.
  76. It's a scientific adventure.
  77. We're boldly exploring this entity
    that connects nature and humanity.
  78. Another reason
    that I'm obsessed with venom

  79. is because of its duality.
  80. When you inject the components
    of a venom arsenal into an organism,
  81. it can kill or it can cure.
  82. At a molecular level,
    several things can happen.
  83. You saw one thing, paralysis in the fish.
  84. Now that was happening
    because the toxins in the venom
  85. were attacking how the fish's cells
    communicate with each other,
  86. preventing it from swimming away.
  87. Are there other things
    that I would like to use venom to attack?

  88. For sure.
  89. And one of those is cancer.
  90. Cancer tumors are cells.
  91. And like all cells,
  92. they communicate with themselves
    and their environment around them.
  93. So we would like to find venom components
  94. that are very good at disrupting
    how the tumor cells communicate.
  95. Similar to how the venom disrupted
    how the fish cells communicated
  96. and the fish couldn't swim away.
  97. In my lab, we study cancer
    as a channelopathy.

  98. What this means is, basically,
    we're looking for venom components
  99. that will target channels
    that are overexpressed in tumor cells
  100. versus normal cells.
  101. The cancer that we're most
    focused on right now
  102. is liver cancer.
  103. And that's because since the 1980s,
  104. the death rate of liver
    cancer has doubled,
  105. and it's an emerging threat in the US.
  106. In a screen in which we had cervical,

  107. neuroblastoma, prostate
    and liver cancer cells,
  108. we found a compound from a terebrid snail
  109. that seems to attack liver cancer cells,
  110. and only liver cancer cells,
    and none of the others that were tested.
  111. And then, when we took this compound
    and we injected it into mouse models
  112. that were expressing liver cancer cells,
  113. it significantly inhibited
    the growth of the tumors.
  114. We're not quite sure how this works yet,
  115. we're still investigating the mechanism
  116. and how we can make
    this compound more effective,
  117. so you can't rush out to the pharmacy
  118. and order up a killer snail
    liver-cancer therapy treatment.
  119. Not yet.
  120. Basically, what we think is happening

  121. is that the compound is blocking
    a specific channel,
  122. prohibiting the transmission
    of a specific chemical
  123. that leads to downstream signaling
  124. that enables the tumor to multiply
    and draw blood to itself.
  125. What we're doing in studying
    the components of venom
  126. to find treatments for human
    diseases and disorders,
  127. is not new,
  128. it's what we call natural
    products drug discovery,
  129. and it's been happening for centuries,
  130. and in cultures all over the world.
  131. Venoms are not only giving us
    cool new compounds,
  132. but they're also giving us
    new ways of thinking
  133. about how we treat
    human diseases and disorders.
  134. And I'll give you three examples.
  135. The first is from killer
    snails, of course.

  136. And so the first drug from these snails
    that is on the market
  137. is called ziconotide, or Prialt,
  138. and it's used to treat chronic pain
    in HIV and cancer patients.
  139. Prialt is a nonaddictive pain therapy.
  140. Three magic words when you think
    about how we're treating pain currently.
  141. We're using things that have
    a huge cost of addiction.
  142. So think of morphine
  143. or think of any of your favorite
    opioid out there.
  144. What the snails have done
  145. is they've shown us a way to treat pain
    without the addiction,
  146. which is huge.
  147. The next example comes
    from the Brazilian pit viper.

  148. From these snakes, we've derived
    a compound called captopril.
  149. Captopril is used to treat
    high blood pressure,
  150. and captopril is a breakthrough drug.
  151. But not only in and of itself,
  152. but because it advanced
    a whole class of drugs,
  153. what we know as ACE inhibitors,
  154. which are the most commonly [prescribed]
    for treating hypertension
  155. and heart failure.
  156. The last example is from the Gila monster.

  157. And this is a really exciting example
    of understanding the ecology
  158. of these organisms,
  159. and pairing it with efficient
    drug discovery.
  160. And Gila monsters are binge eaters.
  161. So when they bite into a large meal,
  162. they release things in their venom
    that lower blood sugar.
  163. So what's the drug that you think
    we found from the Gila monster?
  164. A compound that is used to lower
    the blood sugar in diabetic patients.
  165. Now these are three marvelous examples,

  166. but we've just scratched the surface.
  167. There's so much more venom
    out there for us to study.
  168. In fact, we think that 15 percent
    of all the animals on the planet
  169. are venomous.
  170. And I think this is a low estimate,
  171. given the fact that we haven't surveyed
    all the animals on the planet.
  172. But nature seems to have found
    something that she likes,
  173. and she's repeated it
    over and over and over again,
  174. leading to the vast array of animals
    that we see around us
  175. and all throughout the tree of life.
  176. So whether we're talking
    about my fave, killer snails,

  177. or jellyfish,
  178. or the larvae of butterflies and moths,
  179. or platypus or slow lorises,
  180. whether by sea, land or air,
  181. you're sure to encounter
    a venomous creature.
  182. Remember when I told you
  183. that venom can be both
    a superhero and a supervillain,
  184. and you doubted me?
  185. Mhm.
  186. We're in a race to harness
    all of this venom goodness

  187. before we lose the vast majority
    of animals on our planet.
  188. It's a holistic process.
  189. You can't have the therapeutic treatments
    without having the animals.
  190. And you can't have the animals
  191. without having their ecosystems.
  192. So for me and the snails,
  193. what it means is
    we have to save the oceans.
  194. And because venomous animals
    are found everywhere,
  195. we basically have to save the planet.
  196. So do it for the venomous animals,
  197. if you don't want to do it for yourself.
  198. And who knows,
  199. some day, snail venom
    might just save your life.
  200. Thank you.