[Script Info]
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[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.75,0:00:10.13,Default,,0000,0000,0000,,Imagine something small enough to float\Non a particle of dust
Dialogue: 0,0:00:10.13,0:00:15.95,Default,,0000,0000,0000,,that holds the keys to understanding\Ncancer, virology, and genetics.
Dialogue: 0,0:00:15.95,0:00:17.08,Default,,0000,0000,0000,,Luckily for us,
Dialogue: 0,0:00:17.08,0:00:20.32,Default,,0000,0000,0000,,such a thing exists in the form \Nof trillions upon trillions
Dialogue: 0,0:00:20.32,0:00:24.61,Default,,0000,0000,0000,,of human lab-grown cells\Ncalled HeLa.
Dialogue: 0,0:00:24.61,0:00:26.70,Default,,0000,0000,0000,,Let's take a step back for a second.
Dialogue: 0,0:00:26.70,0:00:30.54,Default,,0000,0000,0000,,Scientists grow human cells in the lab\Nto study how they function,
Dialogue: 0,0:00:30.54,0:00:32.53,Default,,0000,0000,0000,,understand how diseases develop,
Dialogue: 0,0:00:32.53,0:00:35.75,Default,,0000,0000,0000,,and test new treatments without\Nendangering patients.
Dialogue: 0,0:00:35.75,0:00:39.00,Default,,0000,0000,0000,,To make sure that they can repeat\Nthese experiments over and over,
Dialogue: 0,0:00:39.00,0:00:41.70,Default,,0000,0000,0000,,and compare the results \Nwith other scientists,
Dialogue: 0,0:00:41.70,0:00:44.31,Default,,0000,0000,0000,,they need huge populations \Nof identical cells
Dialogue: 0,0:00:44.31,0:00:47.27,Default,,0000,0000,0000,,that can duplicate themselves \Nfaithfully for years,
Dialogue: 0,0:00:47.27,0:00:51.82,Default,,0000,0000,0000,,but until 1951, all human cell lines\Nthat researchers tried to grow
Dialogue: 0,0:00:51.82,0:00:54.09,Default,,0000,0000,0000,,had died after a few days.
Dialogue: 0,0:00:54.09,0:00:57.05,Default,,0000,0000,0000,,Then a John Hopkins scientist\Nnamed George Gey
Dialogue: 0,0:00:57.05,0:01:00.39,Default,,0000,0000,0000,,received a sample of \Na strange looking tumor:
Dialogue: 0,0:01:00.39,0:01:04.20,Default,,0000,0000,0000,,dark purple, shiny, jelly-like.
Dialogue: 0,0:01:04.20,0:01:05.71,Default,,0000,0000,0000,,This sample was special.
Dialogue: 0,0:01:05.71,0:01:07.95,Default,,0000,0000,0000,,Some of its cells just kept dividing,
Dialogue: 0,0:01:07.95,0:01:09.03,Default,,0000,0000,0000,,and dividing,
Dialogue: 0,0:01:09.03,0:01:10.57,Default,,0000,0000,0000,,and dividing.
Dialogue: 0,0:01:10.57,0:01:12.31,Default,,0000,0000,0000,,When individual cells died,
Dialogue: 0,0:01:12.31,0:01:16.17,Default,,0000,0000,0000,,generations of copies took their place\Nand thrived.
Dialogue: 0,0:01:16.17,0:01:21.38,Default,,0000,0000,0000,,The result was an endless source of\Nidentical cells that's still around today.
Dialogue: 0,0:01:21.38,0:01:24.89,Default,,0000,0000,0000,,They very first immortal human cell line.
Dialogue: 0,0:01:24.89,0:01:30.53,Default,,0000,0000,0000,,Guy labeled it "HeLa" after the patient\Nwith the unusual tumor, Henrietta Lacks.
Dialogue: 0,0:01:30.53,0:01:32.62,Default,,0000,0000,0000,,Born on a tobacco farm in Virginia,
Dialogue: 0,0:01:32.62,0:01:35.62,Default,,0000,0000,0000,,she lived in Baltimore with her husband\Nand five children.
Dialogue: 0,0:01:35.62,0:01:38.04,Default,,0000,0000,0000,,She died of aggressive cervical cancer
Dialogue: 0,0:01:38.04,0:01:40.90,Default,,0000,0000,0000,,a few months after her tumorous cells\Nwere harvested,
Dialogue: 0,0:01:40.90,0:01:43.15,Default,,0000,0000,0000,,and she never knew about them.
Dialogue: 0,0:01:43.15,0:01:46.08,Default,,0000,0000,0000,,So what's so special about the cells\Nfrom Henrietta Lacks
Dialogue: 0,0:01:46.08,0:01:49.62,Default,,0000,0000,0000,,that lets them survive\Nwhen other cell lines die?
Dialogue: 0,0:01:49.62,0:01:53.07,Default,,0000,0000,0000,,The short answer is\Nwe don't entirely know.
Dialogue: 0,0:01:53.07,0:01:56.12,Default,,0000,0000,0000,,Normal human cells have built-in\Ncontrol mechanisms.
Dialogue: 0,0:01:56.12,0:01:59.82,Default,,0000,0000,0000,,They can divide about 50 times\Nbefore they self destruct
Dialogue: 0,0:01:59.82,0:02:02.33,Default,,0000,0000,0000,,in a process called apoptosis.
Dialogue: 0,0:02:02.33,0:02:04.65,Default,,0000,0000,0000,,This prevents the propagation\Nof genetic errors
Dialogue: 0,0:02:04.65,0:02:07.88,Default,,0000,0000,0000,,that creep in after \Nrepeated rounds of division.
Dialogue: 0,0:02:07.88,0:02:11.28,Default,,0000,0000,0000,,But cancer cells ignore these signals,\Ndividing indefinitely
Dialogue: 0,0:02:11.28,0:02:13.47,Default,,0000,0000,0000,,and crowding out normal cells.
Dialogue: 0,0:02:13.47,0:02:18.97,Default,,0000,0000,0000,,Still, most cell lines eventually die off,\Nespecially outside the human body.
Dialogue: 0,0:02:18.97,0:02:22.100,Default,,0000,0000,0000,,Not HeLa, though, and that's the part\Nwe can't yet explain.
Dialogue: 0,0:02:22.100,0:02:28.24,Default,,0000,0000,0000,,Regardless, when Dr. Gey realized he had\Nthe first immortal line of human cells,
Dialogue: 0,0:02:28.24,0:02:31.24,Default,,0000,0000,0000,,he sent samples \Nto labs all over the world.
Dialogue: 0,0:02:31.24,0:02:33.58,Default,,0000,0000,0000,,Soon the world's first \Ncell production facility
Dialogue: 0,0:02:33.58,0:02:37.06,Default,,0000,0000,0000,,was churning out \N6 trillion HeLa cells a week,
Dialogue: 0,0:02:37.06,0:02:41.47,Default,,0000,0000,0000,,and scientists put them to work\Nin an ethically problematic way,
Dialogue: 0,0:02:41.47,0:02:44.21,Default,,0000,0000,0000,,building careers and fortunes\Noff of Henrietta's cells
Dialogue: 0,0:02:44.21,0:02:49.84,Default,,0000,0000,0000,,without her or her family's consent,\Nor even knowledge until decades later.
Dialogue: 0,0:02:49.84,0:02:53.97,Default,,0000,0000,0000,,The polio epidemic was at its peak\Nin the early 50s.
Dialogue: 0,0:02:53.97,0:02:57.37,Default,,0000,0000,0000,,HeLa cells, which easily took up\Nand replicated the virus,
Dialogue: 0,0:02:57.37,0:03:00.88,Default,,0000,0000,0000,,allowed Jonas Salk to test his vaccine.
Dialogue: 0,0:03:00.88,0:03:02.63,Default,,0000,0000,0000,,They've been used to study diseases,
Dialogue: 0,0:03:02.63,0:03:03.71,Default,,0000,0000,0000,,including measles,
Dialogue: 0,0:03:03.71,0:03:04.70,Default,,0000,0000,0000,,mumps,
Dialogue: 0,0:03:04.70,0:03:05.77,Default,,0000,0000,0000,,HIV,
Dialogue: 0,0:03:05.77,0:03:07.38,Default,,0000,0000,0000,,and ebola.
Dialogue: 0,0:03:07.38,0:03:09.67,Default,,0000,0000,0000,,We know that human \Ncells have 46 chromosomes
Dialogue: 0,0:03:09.67,0:03:13.24,Default,,0000,0000,0000,,because a scientist working with HeLa\Ndiscovered a chemcial
Dialogue: 0,0:03:13.24,0:03:15.60,Default,,0000,0000,0000,,that makes chromosomes visible.
Dialogue: 0,0:03:15.60,0:03:20.57,Default,,0000,0000,0000,,HeLa cells themselves actually have\Naround 80 highly mutated chromosomes.
Dialogue: 0,0:03:20.57,0:03:24.54,Default,,0000,0000,0000,,HeLa cells were the first to be cloned.
Dialogue: 0,0:03:24.54,0:03:27.27,Default,,0000,0000,0000,,They've traveled to outer space.
Dialogue: 0,0:03:27.27,0:03:28.35,Default,,0000,0000,0000,,Telomerase,
Dialogue: 0,0:03:28.35,0:03:32.59,Default,,0000,0000,0000,,an enzyme that helps cancer cells evade\Ndestruction by repairing their DNA,
Dialogue: 0,0:03:32.59,0:03:34.87,Default,,0000,0000,0000,,was discovered first in HeLa cells.
Dialogue: 0,0:03:34.87,0:03:36.52,Default,,0000,0000,0000,,In an interesting turn of fate,
Dialogue: 0,0:03:36.52,0:03:42.02,Default,,0000,0000,0000,,thanks to HeLa, we know that cervical\Ncancer can be caused by a virus called HPV
Dialogue: 0,0:03:42.02,0:03:44.56,Default,,0000,0000,0000,,and now there's a vaccine.
Dialogue: 0,0:03:44.56,0:03:48.84,Default,,0000,0000,0000,,HeLa-fueled discoveries have filled\Nthousands of scientific papers,
Dialogue: 0,0:03:48.84,0:03:52.25,Default,,0000,0000,0000,,and that number is probably even higher\Nthan anyone knows.
Dialogue: 0,0:03:52.25,0:03:57.05,Default,,0000,0000,0000,,HeLa cells are so resilient that they \Ncan travel on almost any surface:
Dialogue: 0,0:03:57.05,0:03:58.94,Default,,0000,0000,0000,,a lab worker's hand,
Dialogue: 0,0:03:58.94,0:04:00.78,Default,,0000,0000,0000,,a piece of dust,
Dialogue: 0,0:04:00.78,0:04:05.28,Default,,0000,0000,0000,,invading cultures of other cells \Nand taking over like weeds,
Dialogue: 0,0:04:05.28,0:04:10.88,Default,,0000,0000,0000,,countless cures, patents and discoveries\Nall made thanks to Henrieta Lacks.