Visualizing cancer development

Using zebrafish larvae, researchers have for the first time live-imaged the earliest interactions between host environment and oncogene-transformed cells. The research team could see these early associations as the transformed cells gained a growth advantage over normal cells and developed into the precursors of cancer.

Paul Martin (University of Bristol, UK) and colleagues were able to visualize these interactions because zebrafish larvae are translucent (PLoS Biol. 8, e1000562; 2010). They found that the zebrafish immune cells were attracted to the transformed cells before the cells had even formed clones.

Further analysis showed that immune cells were primarily attracted to the hydrogen peroxide generated by both transformed cells and their otherwise healthy neighbor cells. Hydrogen peroxide has been shown to be the essential early damage signal that draws neutrophils to wounds. When the team blocked hydrogen peroxide synthesis, the numbers of neutrophils and macrophages drawn to the transformed cells decreased significantly; this led to reduced numbers of transformed cells. These results suggest that immune cells play a role in early transformed cell growth. The authors note that their results also agree with studies suggesting that cancers resemble non-healing wounds.

A new NIH center

In early December 2010, a US National Institutes of Health (NIH) advisory committee voted to create a new center that will focus on translational science. The National Center for Advancing Translational Sciences would have a budget of $650 million or more and could be operating within one year.

The advisory group, the Scientific Management Review Board, consists of NIH institute directors and outside scientists who are responsible for finding ways to streamline NIH's structure. According to a Nature news article, Francis Collins, director of the NIH, had told this board that “far too often promising diagnostic devices and treatments are not making it to market.”

The new center would absorb the Clinical and Translational Science Awards, which account for almost 40% of the budget of the National Center for Research Resources (NCRR). Some scientists are concerned about the fate of other NCRR programs. Among other programs, NCRR supports a range of comparative medicine programs. “There is no intention here to dismantle [NCRR's other programs],” said Collins in an interview with Nature. “But if there are opportunities to reorganize and reassign these programmes in ways that make them more interactive with what we are trying to do in this new centre, that seems like a good thing to consider.”

Inflammatory response brings mice down

New research led by scientists at Vanderbilt University (Nashville, TN) suggests a link between systemic inflammatory responses and depressive behavior in mice. More work is needed to define the association more thoroughly, but the study results identify a new mechanism for depressive illness and suggest that new therapies targeting inflammatory response pathways may find clinical applications in treating mood disorders.

Randy D. Blakely and William A. Hewlett directed the study, in which they examined the effect of lipopolysaccharide (LPS) administration, which enhances production of inflammatory cytokines, on serotonin transporter (SERT) activity in mouse brains. When SERT activity is increased, serotonin removal from the brain is greater, in turn increasing the risk of mood disorders. They found that SERT activity was greater in mice injected with LPS than in controls and that LPS-treated mice showed behavioral changes suggestive of despair (Neuropsychopharmacology 35, 2510–2520; 2010).

Serotonin is known to affect mood. Certain drugs used to treat depression work by preventing SERT from eliminating serotonin from synapses. And previous work from Blakely's group had indicated that inflammatory cytokines increased SERT activity. The new research helps to link this information to further our understanding of mood disorders.