cancer cells escape from the main tumor.
To get some clues about how tough a
hungry cancer call can be, White and her
colleagues made cells unable to commit
suicide, a hallmark of cancer cells. Then
the team starved the cells.
Even cells that can’t kill themselves
would die eventually if they didn’t
get enough nutrients, the researchers
thought. But in the lab, these cancerlike
cells seemed to do just fine without food.
“When we looked at them closely, we
realized they were eating themselves,”
As these starving cells munched away
on themselves, becoming smaller and
smaller, they eventually went dormant,
existing but not doing much else. That
dormant state can last a week or a month,
depending on the type of cell, White
says. But when the cells were no longer
under so much stress, they rebounded
and began growing again.
Cancer cells in the body may use a
similar strategy to hide and ride out
tough times, then cause a relapse later.
“These are what we call the oncology
horror movies,” White says.
Although scenes of hungry zombie
tumors rising from the dead are terrible, scientists aren’t throwing their
hands over their faces and cowering.
Instead, researchers are experimenting with therapies that may ruin cancer
cells’ self-eating picnics. Clinical trials
are currently under way to determine
if drugs that block autophagy, such as
hydroxychloroquine, can make cancer
cells more vulnerable to chemotherapy.
Dialed up Researchers
have found that a drug
for high blood pressure
boosts autophagy in mice
with Huntington’s disease,
decreasing levels of the
toxic huntingtin protein.
Scientists aren’t sure if
the drug works in people.
SouRce: clAudiA RoSe e T al/
HumaN molecular geNe Tics 2010
Drug’s effect on
Levels of a protein found
on autophagosomes (%)*
*Relative to tubulin, a cell protein
Drug’s effect on
Levels of huntingtin
**Relative to actin, a cell protein
Balance for the brain
Controlling autophagy may also be the
key to quashing neurodegenerative diseases. Though researchers have known
that autophagy is messed up in several
neuron-killing diseases, only recently
have the details come to light.
“In many of these diseases we’re
getting some quite good clues about
what is going wrong when,” says David
Rubinsztein of the Cambridge Institute
for Medical Research and Cambridge
University in England.
For instance, in Parkinson’s disease
globs of a protein called alpha-synuclein
build up in the cell and stop autophago-
somes from swallowing, Rubinsztein and
his colleagues reported last year in the
Journal of Cell Biology. With the cell’s
chomping abilities lost, the toxic protein
continues to build up, eventually leading
to the death of the cell. The same is true
of Huntington’s disease: Autophagy can’t
do its part because of toxic levels of the
huntingtin protein, Rubinsztein and oth-
ers have found.
s Rebecca banerjee et al. “Autophagy in
neurodegenerative disorders.” Trends
in Neurosciences. december 2010.
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