English subtitles

← A new superweapon in the fight against cancer

Get Embed Code
29 Languages

Showing Revision 6 created 04/04/2016 by Cynthia Betubiza.

  1. Cancer affects all of us,
  2. especially the ones that come back
    over and over again.
  3. The highly invasive
    and drug-resistant ones,
  4. the ones that defy medical treatment,
  5. even when we throw our best drugs at them.
  6. Engineering at the molecular level,
  7. working at the smallest of scales,
  8. can provide exciting new ways
  9. to fight the most aggressive
    forms of cancer.
  10. Cancer is a very clever disease.

  11. There are some forms of cancer,
  12. which, fortunately, we've learned
    how to address relatively well
  13. with known and established drugs
    and surgery.
  14. But, there's some forms of cancer
    that don't respond
  15. to these approaches
  16. and the tumor survives
    or comes back,
  17. even after an onslaught of drugs.
  18. We can think of these
    very aggresive forms of cancer

  19. as kind of super villains in a comic book.
  20. They're clever, they're adaptable,
  21. and they're very good at staying alive.
  22. And, like most super villains
    these days,
  23. their super powers come from
    a genetic mutation.
  24. The genes that are modified
    inside these tumor cells
  25. can enable and encode for new
    and unimagined modes of survival,
  26. allowing the cancer cell
    to live through
  27. even our best chemotherapy treatments.
  28. One example is a trick
    in which a gene allows a cell,

  29. even as the drug
    approaches the cell,
  30. to push the drug out before the drug
    can have any effect.
  31. Imagine the cell effectively
    spits out the drug.
  32. This is just one example
    of the many genetic tricks
  33. in the bag of our super villain, cancer.
  34. All due to mutant genes.
  35. So, we have a super villain
    with incredible super powers

  36. and we need a new and
    powerful mode of attack.
  37. Actually, we can turn off a gene,
  38. the key is a set of molecules
    known as siRNA.
  39. siRNA are short sequences
    of genetic code
  40. that guide a cell to block
    a certain gene.
  41. Each siRNA molecule
    can turn off a specific gene
  42. inside the cell.
  43. For many years since its discovery,
  44. scientists have been very excited
  45. about how we can apply
    these gene blockers in medicine.
  46. But, there is a problem.

  47. siRNA works well inside the cell.
  48. But if it gets exposed to the enzymes
    that reside
  49. in our bloodstream or our tissues,
  50. it degrades within seconds.
  51. It has to be packaged, protected
    through its journey through the body
  52. on its way to the final target
    inside the cancer cell.
  53. So, here's our strategy:

  54. first, we'll dose the cancer cell
    with siRNA, the gene blocker,
  55. and silence those survival genes,
  56. and they'll we'll whap it
    with a chemo drug.
  57. But how do we carry that out?

  58. Using molecular engineering,
  59. we can actually design
    a super weapon
  60. that can travel through the blood stream.
  61. It has to be tiny enough
    that it can get through the blood stream,
  62. it's got to be small enough
    to penetrate the tumor tissue,
  63. and it's got to be tiny enough
    to be taken up
  64. inside the cancer cell.
  65. To do this job well, it has to be
    about one 100th the size
  66. of a human hair.
  67. Let's take a closer look
    at how we can build this nanoparticle.

  68. First, let's start with
    the nanoparticle core.
  69. It's a tiny capsule that contains
    the chemotherapy drug.
  70. This is the poison that will
    actually end the tumor cell's life.
  71. Around this core, we'll wrap
    a very thin,
  72. nanometers-thin blanket
    of siRNA.
  73. This is our gene blocker.
  74. Because siRNA is strongly
    negatively charged,
  75. we can protect it with a nice
    protect layer
  76. of postively charged polymer.
  77. The two oppositely charged molecules
  78. stick together through charge attraction
  79. and that provides us with
    a protective layer
  80. that prevents the siRNA from
    degrading in the blood stream.
  81. We're almost done.
  82. (Laughter)
  83. But there is one more big obstacle
    we have to think about.

  84. In fact, it may be the biggest
    obstacle of all.
  85. How do we deploy this super weapon?
  86. I mean, every good weapon
    needs to be targeted,
  87. we have to target this super weapon
    to the super villain cells
  88. that reside in the tumor.
  89. But, our bodies have a natural
    immune defense system.

  90. Cells that reside in the blood stream
  91. and pick out things that don't belong
  92. so that it can destroy or elinate them.
  93. And guess that, our nanoparticle
    is considered a foreign object.
  94. We have to sneak our nanoparticle

  95. past the tumor defense system,
  96. we have to get it past this mechanism
    of getting rid of the foreign object
  97. by disguising it.
  98. So we add one more
    negatively charged layer

  99. around this nanoparticle,
  100. which serves two purposes.
  101. First, this outer layer is one of
    the naturally charged,
  102. highly hydrated polysaccarides
    that resides in our bodies.
  103. It creates a cloud of water molecules
    around the nanoparticle
  104. that gives us
    an invisibility cloaking affect.
  105. This invisibility cloak allows
    the nanoparticle
  106. to travel through the bloodstream
    long and far enough
  107. to reach the tumor without getting
    eliminated by the body.
  108. Second, this layer contains molecules
    which bind specifically

  109. to our tumor's cell.
  110. Once bound, the cancer cell takes up
    the nanoparticle
  111. and now we have our nanoparticle
    inside the cancer cell
  112. and ready to deploy.
  113. Alright, I feel the same way,
    let's go.
  114. (Applause)
  115. The siRNA is deployed first.

  116. It acts for hours,
  117. giving enough time to silence
    and block those survival genes.
  118. We have now disabled those
    genetic superpowers.
  119. What remains is a cancer cell
    with no special defenses.
  120. Then, the chemotherapy drug
    comes out of the core
  121. and destroys the tumor cell
    cleanly and efficiently.
  122. With sufficient gene blockers,
  123. we can address many different kinds
    of mutations.
  124. Allowing the chance to sweep out tumors,
    without leaving behind any bad guys.
  125. So, how does our strategy work?

  126. We've tested these
    nanostructure particles in animals
  127. using a highly aggresive form
    of triple negative breast cancer.
  128. This triple negative breast cancer
    exhibits the gene
  129. that spits out cancer drugs
    as soon as its delivered.
  130. Usually, doxorubicin,
    let's call it dox,

  131. is the cancer drug that is
    the first line of treatment
  132. for breast cancer.
  133. So, we first treated our animals
    with a dox core, dox only.
  134. The tumor slowed their rate of growth,
  135. but they still grew rapidly,
  136. doubling in size
    over a period of two weeks.
  137. Then, we tried our
    combination super weapon.

  138. And now layer a particle
    with siRNA against the chemo pump,
  139. plus, we have the dox in the core.
  140. And look, we found that not only
    did the tumors stop growing,
  141. they actually decerased in size
  142. and were elimintaed
    in some cases.
  143. The tumors were actually
  144. (Applause)
  145. What's great about this approach
    is that it can be personalized,

  146. we can add many different layers
    of siRNA
  147. to address different mutations
    and tumor defense mechanisms
  148. and we can put different drugs
    into the nanoparticle core.
  149. As doctors learn how to test patients

  150. and understand
    certain tumor genetic types,
  151. they can help us determine
    which patients
  152. can benefit from this strategy
  153. and which gene blockers we can use.
  154. Ovarian cancer strikes
    a special chord with me.

  155. It is a very aggresive cancer,
  156. in part because it's discovered
    at very late stages
  157. when its highly advanced
  158. and there are a number
    of genetic mutations.
  159. After the first round of chemotherapy,
  160. this cancer comes back
    for 75 percent of patients.
  161. And it usually comes back
    in a drug resistant form.
  162. High-grade ovarian cancer
  163. is one of the biggest
    super villains out there.
  164. And we're now directlng
    our super weapon
  165. towards its defeat.
  166. As a researcher,

  167. I usually don't get to work with patients.
  168. But I recently met a mother
  169. who is an ovarian cancer survivor,
    Mimi, and her daughter Paige.
  170. I was deeply inspired
  171. by the optimism and strength
  172. that both mother and daughter displayed
  173. and by their story of courage and support.
  174. At this event, we spoke about
    the different technologies

  175. directed at cancer.
  176. And Mimi was in tears
    as she explained how
  177. learning about these efforts
  178. gives her hope for future generations,
  179. including her own daughter.
  180. This really touched me.
  181. It's not just about building
    really elegant science,
  182. it's about changing people's lives.
  183. It's about understanding the power
    of engineering
  184. on the scale of molecules.
  185. I know that as students like Paige

  186. move forward in their careers,
  187. they'll open new possibilites
  188. in addressing some of the big
    health problems in the world,
  189. including, ovarian cancer,
    neurological disorders,
  190. infectious disease.
  191. Just as chemical engineering
    has found a way
  192. to open doors for me.
  193. Has provided a way of engineering
    on the tiniest scale,
  194. that of molecules
  195. to heal on the human scale.
  196. Thank you

  197. (Applause)