DISAMPING KANAN INI.............
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'Rewired'
tikus menunjukkan tanda-tanda kehidupan lebih lama dengan lebih sedikit
penyakit yang berkaitan
dengan usia
Ketika mengembangkan
obat kanker baru, para peneliti menemukan bahwa tikus yang kurang protein tertentu hidup lebih lama dengan lebih
sedikit penyakit berkaitan dengan usia. Tikus, yang kurang protein TRAP-1, menunjukkan kurangnya usia
degenerasi jaringan terkait, obesitas dan pembentukan tumor spontan bila
dibandingkan dengan tikus normal . Temuan ini bisa mengubah bagaimana para
ilmuwan melihat metabolik jaringan dalam sel.
'Rewired' mice show signs of longer lives with fewer age-related
illnesses
Date:
July 31,
2014
Source:
The Wistar Institute
Summary:
While developing a new cancer drug, researchers
discovered that mice lacking a specific protein live longer lives with fewer
age-related illnesses. The mice, which lack the TRAP-1 protein, demonstrated
less age related tissue degeneration, obesity, and spontaneous tumor formation
when compared to normal mice. Their findings could change how scientists view
the metabolic networks within cells.
.......................
While developing a new cancer drug, researchers at The
Wistar Institute discovered that mice lacking a specific protein live longer
lives with fewer age-related illnesses. The mice, which lack the TRAP-1 protein,
demonstrated less age-related tissue degeneration, obesity, and spontaneous
tumor formation when compared to normal mice. Their findings could change how
scientists view the metabolic networks within cells.
In healthy
cells, TRAP-1 is an important regulator of metabolism and has been shown to
regulate energy production in mitochondria, organelles that generate chemically
useful energy for the cell. In the mitochondria of cancer cells, TRAP-1 is
universally overproduced.
The Wistar
team's report, which appears in the journal Cell Reports, shows how
"knockout" mice bred to lack the TRAP-1 protein compensate for this
loss by switching to alternative cellular mechanisms for making energy.
"We see
this astounding change in TRAP-1 knockout mice, where they show fewer signs of
aging and are less likely to develop cancers," said Dario C. Altieri.
M.D., Robert and Penny Fox Distinguished Professor and director of The Wistar
Institute's National Cancer Institute-designated Cancer Center. "Our findings
provide an unexpected explanation for how TRAP-1 and related proteins regulate
metabolism within our cells."
"We
usually link the reprogramming of metabolic pathways with human diseases, such
as cancer," Altieri said. "What we didn't expect to see were
healthier mice with fewer tumors."
Altieri and
his colleagues created the TRAP-1 knockout mice as part of their ongoing
investigation into their novel drug, Gamitrinib, which targets the protein in
the mitochondria of tumor cells. TRAP-1 is a member of the heat shock protein
90 (HSP90) family, which are "chaperone" proteins that guide the
physical formation of other proteins and serve a regulatory function within
mitochondria. Tumors use HSP90 proteins, like TRAP-1, to help survive
therapeutic attack.
"In
tumors, the loss of TRAP-1 is devastating, triggering a host of catastrophic
defects, including metabolic problems that ultimately result in the death of
the tumor cells," Altieri said. "Mice that lack TRAP-1 from the
start, however, have three weeks in the womb to compensate for the loss of the
protein."
The
researchers found that in their knockout mice, the loss of TRAP-1 causes
mitochondrial proteins to misfold, which then triggers a compensatory response
that causes cells to consume more oxygen and metabolize more sugar. This causes
mitochondria in knockout mice to produce deregulated levels of ATP, the
chemical used as an energy source to power all the everyday molecular reactions
that allow a cell to function.
This
increased mitochondrial activity actually creates a moderate boost in oxidative
stress ("free radical damage") and the associated DNA damage. While
DNA damage may seem counterproductive to longevity and good health, the low
level of DNA damage actually reduces cell proliferation -- slowing growth down
to allow the cell's natural repair mechanisms to take effect.
According to
Altieri, their observations provide a mechanistic foundation for the role of
chaperone molecules, like HSP90, in the regulation of bioenergetics in
mitochondria -- how cells produce and use the chemical energy they need to
survive and grow. Their results explain some contradictory findings in the
scientific literature regarding the regulation of bioenergetics and
dramatically show how compensatory mechanisms can arise when these chaperone
molecules are taken out of the equation.
"Our
findings strengthen the case for targeting HSP90 in tumor cells, but they also
open up a fascinating array of questions that may have implications for
metabolism and longevity," Altieri said. "I predict that the TRAP-1
knockout mouse will be a valuable tool for answering these questions."
This work
was supported by grants to Altieri from the National Institutes of Health (P01
CA140043, R01 CA78810) and the Office of the Assistant Secretary of Defense for
Health Affairs through the Prostate Cancer Research Program (W81XWH-13-1-0193).
Additional support was provided through the National Cancer Institute Cancer
Center Support Grant (CA010815) to The Wistar Institute.
Co-authors
from the Altieri lab include Sofia Lisanti, Michele Tavecchio, Ph.D., and Young
Chan Chae, Ph.D., Wistar co-authors also include Qin Liu, M.D., Ph.D., an
associate professor in Wistar Cancer Center's Molecular and Cellular
Oncogenesis program. Co-authors from outside Wistar include Angela K. Brice,
D.V.M., Ph.D., from the University of Pennsylvania School of Veterinary
Medicine, and Madhukar L. Thakur, Ph.D., and Lucia R. Languino, Ph.D., from
Thomas Jefferson University.
Story
Source:
The above
story is based on materials provided by The Wistar Institute. Note: Materials may be edited
for content and length.
Journal
Reference:
- Sofia Lisanti, Michele Tavecchio, Young Chan Chae, Qin Liu, Angela K. Brice, Madhukar L. Thakur, Lucia R. Languino, Dario C. Altieri. Deletion of the Mitochondrial Chaperone TRAP-1 Uncovers Global Reprogramming of Metabolic Networks. Cell Reports, 2014; DOI: 10.1016/j.celrep.2014.06.061