Sources & further reading: https://sites.google.com/view/sources-cancervsimmune/
This video was partially financed by Gates Ventures.
If you want to support this channel and get something nice in return check out our shop: https://kgs.link/shop-176
Somewhere in your body, your immune system just quietly killed one of your own cells, stopping it from becoming cancer, and saving your life. It does that all the time. The vast majority of cancer cells you develop will be killed without you ever noticing. Which is an incredibly hard job because of what cancer cells are: parts of yourself that start to behave as individuals even if it hurts you.
What is cancer and how does your body kill it all the time?
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Somewhere in your body, your immune system
just quietly killed one of your own cells, stopping it from becoming cancer, and
saving your life. It does that all the time. The vast majority of cancer cells you
develop will be killed without you ever noticing. Which is an incredibly hard
job because of what cancer cells are: parts of yourself that start to behave
as individuals even if it hurts you. What is cancer and how does
your body kill it all the time? INTRO Cancer is when corrupted
cel
ls multiply uncontrollably. It can emerge from basically
every type of cell in your body, so there is not just a single
type of cancer but hundreds. Some grow slowly, others are aggressive, some
can be treated effectively, others are deadly. In a sense, a cell that becomes cancer turns
into something ancient and something new. Over billions of years, evolution has molded cells
to survive and thrive in a hostile environment, fighting for space and resources. Until a new
and exciting way of
life emerged: Cooperation, a division of labour that allowed cells to
specialize and become more successful together. But cooperation requires sacrifices. For
a multicellular being to stay healthy, the wellbeing of the collective has to matter
more than the survival of the individual cell. Cancer cells stop being part of the
collective and become individuals again. Your body can handle a few rogue cells but
some cancer cells divide, again, and again, becoming a sort of new organism within
you. Taking resources you need to survive, competing for the space you inhabit, destroying
the organs they were part of in the process. Despite the harm they cause, cancer cells
are not evil. They don’t want to hurt you. They don’t want anything. Cells are protein
robots that just follow their programming, which unfortunately has been corrupted. The Soul of the Cell In a nutshell, your cells have a nucleus filled
with DNA. It consists of genes – instructions for how to build proteins and whe
n to make
each one.These building instructions are copied and transferred to ribosomes, where
they are used to make proteins. What kind of proteins your cells make determine what
they can do. The important thing here is that a corrupt gene means you get a corrupt
protein, which will get important later. Your DNA gets a tiny bit corrupted – it
mutates – tens of thousands of times each day. Most of the time without any
special cause, just by being alive. Almost all of these mutations are fix
ed
very quickly or are not problematic. Still, over time as your cells
make copies of themselves, damage is accumulating. Imagine having
to make copies from copies from copies, for decades. Maybe one day a hair got
on the scanner or a corner got frayed. Each new mistake becomes part of the new
copies and all the copies that follow. You can increase DNA damage by doing
things like smoking, drinking alcohol, by being obese, breathing in asbestos, by
not using sunscreen or contracting a viru
s like HPV. But the simplest way to damage DNA
and get cancer is to be alive long enough. For many cancer cases, there is
no cause other than bad luck. The Damage that leads to Cancer We are simplifying, but roughly, there are three categories of genes that
need to be corrupted so cancer can arise. The first key mutation is in the appropriately
named tumor suppressor genes, or TSGs. These genes are a bunch of things. For
one, they produce control mechanisms that continuously scan your DNA f
or mistakes
and copying errors and fix them right away. And then they keep normal cells from
multiplying recklessly. If TSGs become damaged, your cells basically forget how to repair
themselves and can reproduce unchecked. The second crucial mutation can happen in your
oncogenes. When oncogenes are turned on the cell is told to multiply rapidly.They were super
active when you were inside your mother’s womb. To turn a single original cell into
trillions in months, it needs to divide and gro
w rapidly. These rapid growth genes
are turned off when there is enough of you. When your oncogenes get corrupted,
they basically turn on again. The third crucial mutation is
in your cells’ suicide switch. Most cells are constantly recycled and refreshed.
When cells amass too much damage, they usually notice and special genes trigger a controlled
suicide called apoptosis. If the genes that control this process get damaged, cells are free
to live on despite being dangerously corrupted. So i
f a cell becomes unable to fix
the mistakes in its genetic code, loses the ability to destroy itself
when it notices the damage, and begins to grow rapidly without restraint,
it turns into a young cancer cell. These cells have to be killed as quickly as
possible: while they are bad at this stage, they are still pretty weak and easy to
kill. But if they continue to mutate and increase in number, they can learn to avoid
your defenses and become a real threat. At any moment of your life, your
immune
system is hunting these cells. But how do you identify and kill corrupted cells that
seem indistinguishable from healthy ones? How to Find Cancer Well, here we come back to the proteins your
cells produce and the story they tell. So if for example, your oncogenes switch back
on, they make oncogene proteins. Your immune system knows that they should
not be present if you are an adult. So to know which cells are
corrupt and which are healthy, your immune system needs to know what pro
teins
they are making inside. To solve this evolution came up with MHC class I molecules, a sort of
display window that makes cells transparent. Cells constantly take little samples of
the proteins they make and put them into thousands of these MHC molecules,
to showcase what they are doing. The selection is constantly refreshed,
always giving an up to date picture. There is a whole library of proteins that
are highly dangerous and should not be made by healthy cells, and your immune syste
m has them
all on file. It has billions of specialized cells, called T Cells, made to recognize specific
proteins. If a T Cell sees a forbidden protein in an MHC display window, it knows that the
cell is corrupted and kills it immediately. But there is a flaw in this system. What if a cancer cell mutates and finds
a way to circumvent this process? All it needs to do is to stop making MHC Class
I molecules, and boom, it’s invisible. Without display windows, the immune system
is blind and ca
n’t identify cancer anymore. Fortunately evolution found an ingenious solution: The Natural Killer Cell. A
judge, jury and executioner. The Killer At this very second, hundreds of millions of
Natural Killer Cells are patrolling your body looking for cells that have already turned
into cancer or are corrupted by a virus. Natural Killer Cells go from cell to cell to
check for one thing: Does a cell have MHC class I molecules? Does it have a display window and is
it doing its duty of showing o
ff what is going on inside itself? This is so amazing because it
covers all of your bases: While T Cells look for the presence of the unexpected, something
that should not be here, Natural Killer Cells look for the absence of the expected, the
absence of something that should be here. The logic is: if a cell does
not have display windows, it wants to hide something. And a cell
that hides something must be killed. What makes the Natural Killer Cell even more
metal, is that it is always in m
urder mode. It patrols your body, checking cell after
cell with the intention of killing it. Your healthy cells have to convince it that they should not die today. And a way to do
that is to have MHC class I molecules. So in summary, almost all young cancer cells you
will ever develop in your life will be killed by your immune system. Ok, but if your body is
this prepared, why do we still get cancer? Well, sometimes cancer cells mutate more
and get much better at fighting back. Cancer is a
story of an arms race. An arms race
that we will win eventually, maybe with the help of Natural Killer cells! Right now a number of
therapies are beginning to show amazing promise, from cancer fighting vaccines, to engineered T
Cells and even Natural Killer cells – we will look at these therapies in future videos.
So the war is not won yet, but we are on to cancer and eventually it will be eliminated
once and for all – maybe sooner than we think.
Comments
Sources & further reading: https://sites.google.com/view/sources-cancervsimmune/ This video was partially financed by Gates Ventures. If you want to support this channel and get something nice in return check out our shop: https://kgs.link/shop-176
I couldn't help but imagine a movie or show where the main character is one of those classic rebel heroes, running from special agents and fighting to dismantle the system that forces everyone to do their assigned job and toe the line... Only to find out that our "hero" is a cancer cell, the "system" is a human body, and the "special agents" are T-cells from the immune system... Would really be a mind-bender! LOVED this episode!!
I'm an immunologist and I've worked on immunotherapy research to fight cancer, I know all of this and yet I would've never presented it as well as you did, thank you for making knowledge accessible and fun whilst still being accurate enough! Love your channel.
Idk why but it really makes you appreciate your body even more. It's almost like your body is like your best friend or a wingman always got your back until it's overwhelmed
I have a PhD in cancer research and this is the best ‘nut shell’ explanation and visualisation I have ever come across. Well done team!
As a cancer cell, thank you for explaining it much better than we can ever do!
Words cant express my gratitude for igrotum. Its providing relief and healing during a challenging time.
The fact that in school I was almost falling asleep listening to the slides the teachers made about this, but when I watch this video I never even thought of clicking off and was interested the whole time. Massive round of applause to the animation team and the person who’s speaking.
I've been fighting cancer for almost 5 years its been a struggle. I've done so much chemotherapy and it wasn't able to kill the cancer off. It came back after a year later, i fought it off 3 times. i recently went through surgery and with that its going away so i can finally say im done with cancer.😊
As a PhD student in Genetics, I knew most of the information in this video, but the way it is presented it is exceptionally good. First year undergrad students would understand more from this video than from a 2-hour lecture.
the animation team really needs an applause
I really appreciate how you've taken constructive criticism to heart. Instead of being really defensive you guys have taken the people calling you "propaganda" and used their feedback to grow.
I can’t express how amazing this channel is. It deserves its own TV show on streaming services
As a natural killer cell, thank you so much for the positive representation in this video!
I don't know why I just discovered your channel today. I love knowledge and I am always searching it out. Anyway, you guys rock and I am so excited to binge your channel today!! Thank you
I have always been really scared of getting cancer ever since I first learned it was a thing as very young child. This video was very interesting and educational, and now I’m not as scared anymore. Thank you :)
It’s so tragic that just one failure to destroy a cancerous cell can lead to someone’s death.
As a T-cell, thanks a bunch for bringing such recognition to my colleague. It was well deserved. We work hard everyday killing to stay alive.
Wow, the effort and dedication you guys put in these videos is just more than amazing. thank you so much. keep going.
the animation team really needs an applause. It always amazed my mind how impossibly complex our immune system is..