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← A new superweapon in the fight against cancer

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Showing Revision 2 created 04/03/2016 by Cynthia Betubiza.

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    Cancer affects all of us,
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    especially the ones that come back
    over and over again.
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    The highly invasive
    and drug-resistant ones,
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    the ones that defy medical treatment,
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    even when we throw our best drugs at them.
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    Engineering at the molecular level,
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    working at the smallest of scales,
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    can provide exciting new ways
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    to find the most aggressive
    forms of cancer.
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    Cancer is a very clever disease.
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    There are some forms of cancer,
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    which, fortunately, we've learned
    how to address relatively well
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    with known and established drugs
    and surgery.
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    But, there's some forms of cancer
    that don't respond
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    to these approaches
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    and the tumor survives
    or comes back,
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    even after an onslaught of drugs.
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    We can think of these
    very aggresive forms of cancer
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    as kind of super villains in a comic book.
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    They're clever, they're adaptable,
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    and they're very good at staying alive.
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    And, like most super villains
    these days,
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    their super powers come from
    a genetic mutation.
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    The genes that are modified
    inside these tumor cells
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    can enable and encode for new
    and unimagined modes of survival,
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    allowing the cancer cell
    to live through
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    even our best chemotherapy treatments.
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    One example is a trick
    in which a gene allows
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    a cell, even as the drug
    approaches the cell,
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    to push the drug out before the drug
    can have any effect.
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    Imagine the cell effectively
    spits out the drug.
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    This is just one example
    of the many genetic tricks
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    in the bad of our super villain, cancer.
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    All due to mutant genes.
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    So, we have a super villain
    with incredible super powers
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    and we need a new and
    powerful mode of attack.
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    Actually, we can turn off a gene,
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    the key is a set of molecules
    called siRNA.
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    siRNA are short sequences
    of genetic code
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    that guide a cell to block
    a certain gene.
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    Each siRNA molecule
    can turn off a specific gene
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    inside the cell.
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    For many years since its discovery,
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    scientists have been very excited
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    about how we can apply
    these gene blockers in medicine.
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    But, there is a problem.
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    siRNA works well inside the cell.
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    But if it gets exposed to the enzymes
    that reside
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    in our bloodstream and our tissues,
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    it degrades within seconds.
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    It has to be packaged, protected
    through its journey through the body
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    on its way to its final target
    inside the cancer cell.
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    So, here's our strategy:
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    first, we'll dose the cancer cell
    with siRNA, the gene blocker,
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    and silence those viral genes,
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    and they'll we'll whap (?) it
    with a chemo drug.
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    But how do we carry that out?
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    Using molecular engineering,
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    we can actually design
    a super weapon
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    that can travel through the blood stream.
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    It has to be tiny enough
    that it can get through the blood stream,
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    it's got to be small enough
    to penetrate the tumor tissue,
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    and it's got to be tiny enough
    to be taken up
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    inside the cancer cell.
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    To do this job well, it has to be
    about one 100th the size
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    of a human hair.
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    Let's take a closer look
    at how we can build this nanoparticle.
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    First, let's start with
    the nanoparticle core.
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    It's a tiny capsule that contains
    the chemotherapy drug.
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    This is the poison that will
    actually end the tumor cell's life.
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    Around this core, we'll wrap
    a very thin,
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    nanometer-think blanket
    of siRNA.
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    This is our gene blocker.
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    Because siRNA is strongly negatively charged,
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    we can protect it with a nice
    protect layer
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    of postively charged polymer.
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    The two oppositely charged molecules
    stick together throough charge attracttion,
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    and that provides us with a protective