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← A new superweapon in the fight against cancer

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Showing Revision 4 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 find 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
  29. a cell, 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 bad 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
    called 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 and 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 its 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 viral 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. nanometer-think 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
    stick together throough charge attracttion,
  78. and that provides us with a protective
  79. that prevents the sIRNA from
    degrading the blood stream.
  80. We're almost done.
  81. (Laughter)
  82. But there is one more big obstacle
    we have to think about.
  83. In fact, i tmay be the biggest
    obstacle of all.
  84. How do we deploy this super weapon?
  85. I mean, every good weapon
    needs to be targeted,
  86. we need to target this super weapon
    to the super villain cells
  87. that we find in the tumor.
  88. But, our bodies have a natural
    immune defense system.
  89. Cells that reside in teh blood stream
  90. and pick out things that don't belong
  91. so that it can destroy or elinate them.
  92. And guess that, our nanoparticle
    is considered a foreign object.
  93. We have to sneak our nanoparticle
  94. past the tumor dfense system,
  95. we have to get it past this mechanism
    of getting rid of the foreign object
  96. bu disguising it.
  97. So we add one more negatively charged layer
  98. around this nanoparticle,
  99. which serves two purposes.
  100. First, this outer layer is one of
    the naturally charged,
  101. highly hydrated polysaccarides
    that resides in our bodies.
  102. It creates a cloud of water molecules
    around the nanoparticle
  103. that gives us an invisibility cloaking affect.
  104. This invisibility cloak allows
    the nanoparticle
  105. to travel through the bloodstream
    long and far enough
  106. to reach the tumor without getting
    eliminated by the body.
  107. Second, this layer contains molecules
    which bind specifically
  108. to our tumor's cell.
  109. Once bound, the cancer cell takes up
    the nanoparticle
  110. and now we have our nanoparticle
    inside the cancer cell
  111. and ready to deploy.
  112. Alright, I feel the same way,
    let's go.
  113. (Applause)
  115. It acts for hours,
  116. giving enough time to silence
    and block those survival genes.
  117. We have now disabled those
    genetic superpowers.
  118. What remains is a cancer cell
    with no special defenses.
  119. Then, the chemotherapy drug
    comes out of the core
  120. and destroys the tumor cell
    cleanly and efficiently.
  121. With sufficient gene blockers,
  122. we can address many different kinds
    of mutations.
  123. Allowing the chance to sweep out tumors,
    without leaving behind any bad guys.
  124. So, how does our strategy work?
  125. We've tested these nano-strucutre particles
    in animals
  126. using a highly aggresive form
    of triple negative breast cancer.
  127. This triple negative breast cancer
    exhibits the gene
  128. that spits out cancer drugs
    as soon as its delivered.
  129. Usually, ?, let's call it ?
  130. is the cancer drug that is
    the first line of treatment
  131. for breast cancer.
  132. So, we first treated our animals
    with dox core, dox only.
  133. The tumor slowed their rate of growth,
  134. but they still grew rapidly,
  135. doubling in size over a period of two weeks.
  136. Then, we tried our combination super weapon.
  137. And now layer a particle
    with siRNA against the chemo pump,
  138. plus, we have the doxs in the core.
  139. And look, we found that not only
    did the tumors stop growing,
  140. they actually decerased in size
  141. and were elimintaed
    in some cases.
  142. The tumors were actually
  143. (Applause)
  144. What's great about this approach
    is that it can be personalized,
  145. we can add many different layers
    of siRNA
  146. to address different mutations
    and tumor defense mechanisms
  147. and we can put different drugs
    into the nanoparticle core.
  148. As doctors learn how to test patients
    and understand
  149. certain tumor genetic types,
  150. they can help us determine
    which patients
  151. can benefit from this strategy
  152. and which gene blockers we can use.
  153. Ovarian cancer strikes
    a special chord with me.
  154. It is a very aggresive cancer,
  155. in part because it's discovred
    at very late stages
  156. when its highly advanced
  157. and there are a number
    of genetic mutations.
  158. After the first round of chemotherapy,
  159. this cancer comes back
    for 75 percent of patients.
  160. And it usually comes back
    in a drug resistant form.
  161. High-grade ovarian cancer
    is one of
  162. the biggest super villains out there.
  163. And we're now directlng
    this super weapon
  164. towards its defeat.
  165. As a researcher,
  166. I usually don't get to work with patients,
  167. but I recently met a mother
  168. who is an ovarian cancer survivor,
    Mimi and her daughter pAIGE.
  169. I was deeply inspired
  170. by the optimism and strength
  171. that both mother and daughter displayed.
  172. And by their story of courage and support.
  173. At this event, we spoke about
    the different technologies
  174. directed at cancer.
  175. And Mimi was in tears
    as she explained how
  176. learning about these efforts
  177. gives her hope for future generations,
  178. including her own daughter.
  179. This really touched me.
  180. It's not just about building
    really elegant science,
  181. it's about changing people's lives.
  182. It's about understanding the power
    of engineering
  183. on the scale of molecules.
  184. I know that as students like Paige
  185. move forward in their careers,
  186. they'll open new possibilites
  187. in addressing some of the big
    health problems in the world.
  188. Including, ovarian cancer,
    neurological disorders,
  189. and infectious disease.
  190. Just as chemical engineering
    has found a way
  191. to open doors for me.
  192. Has provided a way of engineering
    on the tiniest scale
  193. that of molecules
  194. to heal on the human scale.
  195. Thank you
  196. (Applause)