Mice and rats have long since been a standard animal model for cancer research,
mainly due to their short lifespans (four years on average) and high incidence
of cancer. Naked mole rats, however, are a mystery among mammals. This tiny
African subterranean rodent, which is very social, can live for over 30 years
and, most surprisingly, is cancer-resistant.
The fact that so far, not a
single incident of cancer has been detected in one of these animals makes the
naked mole rat an attractive model for finding novel ways to fight
Recently, a joint team of researchers frin University of
Rochester in New York and the University of Haifa discovered that when secreted
from the naked mole rat’s cells, high-molecular-mass Hyaluronan (HMM-HA)
prevents cells from overcrowding and forming tumors.
a powerful anti-cancer mechanism that arrests cell growth when cells come into
contact with each other, is lost in cancer cells”, explains Prof. Eviatar Nevo,
from the University of Haifa’s institute of evolution.
showed that when HMM-HA was removed from naked mole rat cells, they became
susceptible to tumors and lost their contact inhibition.”
HMM-HA is a
form of Hyaluronan, a long sugar polymer, naturally present as a lubricant in
the extracellular matrix of the human body. It is commonly used in the treatment
of arthritis or in anti-wrinkle skin-care products.
According to the
current results, the naked mole rat cells secrete extremely high-molecular mass
HA, over five times larger than human or mouse HA.
Nevo, “the cells of the Israeli solitary blind mole rat, Spalax, which is
phylogenetically closer to mice and rats than to naked mole rats, also secreted
HMM-HA. This highlights a parallel evolution in unrelated subterranean mammals,
presumably a shared adaptation to life underground.”
speculate that naked mole rats evolved higher concentrations of HA in the skin
to provide the skin elasticity needed for life in underground tunnels.
far, experiments in human cells have been very limited.
has been some evidence showing there is reason for hope. In one of their
experiments, the researchers noticed that when naked mole rat HAS2 synthesis
protein was overexpressed in human cell tissues, the cells began secreting
HMM-HA. This opens new avenues for cancer prevention and life extension in human
TURNING TRASH INTO CASH
Suppose you could replace “Made in
China” with “Made in my garage”? Michigan Technological University’s Joshua
Pearce is working on it. His main tool is opensource 3D printing, which he uses
to save thousands of dollars by making everything from his lab equipment to his
Using free software downloaded from sites like Thingiverse,
which now holds over 54,000 open-source designs, 3D printers make all manner of
objects by laying down thin layers of plastic in a specific pattern. While
high-end printers can be very expensive, simpler opensource units run between
$250 and $500 – and can be used to make parts for other 3D printers, driving the
cost down ever further.
“One impediment to even more widespread use has
been the cost of filament,” says Pearce, an associate professor of materials
science and engineering and electrical and computer engineering.
vastly less expensive than most manufactured products, the plastic filament that
3D printers transform into useful objects isn’t free. Milk jugs, on the other
hand, are a costly nuisance, either to recycle or to bury in a landfill. But if
you could turn them into plastic filament, Pearce reasoned, you could solve the
disposal problem and drive down the cost of 3D printing even more.
Pearce and his research group decided to make their own recycling unit, or
RecycleBot. They cut the labels off milk jugs, washed the plastic and shredded
Then they ran it through a homemade device that melts and extrudes it
into a long, spaghetti-like string of plastic.
Their process is
open-source and free for everyone to make and use at Thingiverse.com.
process isn’t perfect. Milk jugs are made of highdensity polyethylene, or HDPE,
which is not ideal for 3D printing. “HDPE is a little more challenging to print
with,” Pearce says. But the disadvantages are not overwhelming.
made its own climate-controlled chamber using a small refrigerator and an
off-the-shelf humidifier and had good results. With more experimentation, the
results would be even better, he says. “3D printing is [today] where computers
were in the 1970s.”
RecycleBots and 3D printers have all kinds of
applications, but they would be especially useful in areas where shopping malls
are few and far between, Pearce believes. “Three billion people live in rural
areas that have lots of plastic junk,” he says. “They could use it to make
useful consumer goods for themselves. Or imagine people living by a landfill in
Brazil, recycling plastic and making useful products or even just ‘fair trade
filament’ to sell.
Twenty milk jugs gets you about one kilogram of
plastic filament, which currently costs $30 to $50 online.”