Study Uncovers Pathway Critical for
Scientists have made an unanticipated discovery
in mice that interferon-gamma, a type of protein primarily used by the immune system
for intercellular communication, acts as a promoter for the deadly form of skin cancer
known as melanoma. This finding resulted from a series of experiments designed to understand
how solar ultraviolet (UV) radiation causes melanoma.
Results of this study suggest that interferon-gamma, which has been thought to contribute to an innate defense system against cancer, under
some circumstances may promote melanoma
and incite the development of tumors. The work, led by Dr. Glenn Merlino of NCI’s Laboratory
of Cancer Biology and Genetics and research
fellow and first author Dr. M. Raza Zaidi, appeared online Jan. 19 in Nature. Cutaneous melanoma is a highly aggressive and frequently
drug-resistant cancer with rising incidence rates. The major environmental risk factor for melanoma is UV radiation exposure, usually from the sun, with the highest risk associated with intermittent burning doses, especially during
Over the past 10 years, the researchers used genetically
engineered mice first to prove, and then to try to understand, the connection between exposure to UV radiation and the initiation of melanoma. The current work was the latest attempt
to define the molecular mechanisms of this cause and effect relationship. The results of this study offer the possibility that the inhibition
of interferon-gamma immediately after sunburn might block the carcinogenic activation of the skin’s pigment-producing cells, known as melanocytes, making it a potentially effective
preventive strategy against UV radiation-induced
melanoma, according to the scientists.
Rebooting the Brain Helps Stop the Ring of Tinnitus
The hallmark of tinnitus is often a persistent ringing in the ears that is annoying for some, debilitating
for others and currently incurable. Similar to pressing a reset button in the brain, the new therapy was found to help retrain the part of the brain that interprets sound so that errant neurons reverted back to their original state and the ringing disappeared.
NIH-funded researchers were able to eliminate
tinnitus in a group of rats by stimulating a nerve in the neck while simultaneously playing a variety of sound tones over an extended period
of time, says a study published Jan. 12 in the advance online edition of Nature. The hallmark of tinnitus is often a persistent ringing in the ears that is annoying for some, debilitating for others and currently
incurable. Similar to pressing a reset button in the brain, this new therapy was found to help retrain the part of the brain that interprets sound so that errant neurons reverted back to their original state and the ringing disappeared.
The research was conducted by scientists
from the University of Texas at Dallas and MicroTransponder Inc. NIDCD funded a large part of the research.
Tinnitus is a symptom some people experience as a result of hearing loss. When sensory cells in the inner ear are damaged, such as from loud noise, the resulting hearing loss changes some of the signals sent from the ear to the brain. For reasons that are not fully understood, some people will develop tinnitus as a result.
New Technology Peeks Deep into the Brain
Changes within deep regions of the brain can now be visualized at the cellular level, based on NIH-funded research on mice. Published online in the Jan. 16 Nature Medicine, the study used a groundbreaking technique to explore cellular-level changes over a period of weeks within deep brain regions, providing a level of detail not possible
with previously available methods. NIDA, NCI and NINDS supported the study. Researchers
at Stanford University used time-lapse fluorescence
microendoscopy, a technique that uses miniature probes to directly visualize specific cells over a period of time, to explore structural
changes that occur in neurons as a result of tumor formation and increased stimulation in the mouse brain. This could lead to greater information
on how the brain adapts to changing situations,
including repeated drug exposure.
“Continued drug use leads to changes in neuronal
circuits that are evident well after a person
stops taking an addictive substance,” said NIDA director Dr. Nora Volkow. “This study demonstrates an innovative technique that allows for a glimpse of these cellular changes
within the brain regions implicated in drug reward, providing an important tool in our understanding and treatment of addiction.”—