Scientists from Lawrence Livermore, in collaboration with researchers from the University of California (UC) campuses at Merced and Davis, have found that a specific secreted protein inhibits prostate cancer metastasis to bone. Their research appears in the October 29, 2015, issue of the journal Microarrays and in the November 6, 2015, edition of PLOS ONE.
If prostate cancer is detected at early stages, the prognosis is favorable, but aggressive forms spread primarily to the skeleton. Bone tumors cause great pain, promote fractures, and ultimately represent the main cause of morbidity, with a 70 percent incidence documented by autopsies. Aimy Sebastian, a UC Merced graduate student conducting her Ph.D. thesis work under Livermore’s Gabriela Loots (both are shown in the above photograph), led a study that identified the secreted bone protein sclerostin (SOST) as a key molecule dysregulated as a result of prostate cancer–bone microenvironment interactions. This study, published in Microarrays, shows that the lack of SOST in the bone microenvironment promotes the expression of genes associated with cell migration and invasion, including those in prostate cancer, suggesting that SOST has an inhibitory effect on prostate cancer invasion.
A second study, which included Livermore biomedical scientist Nicholas Hum, looked into the role of SOST in regulating prostate cancer invasion and metastasis. They found that prostate cancer cells producing more SOST had significantly lower rates of metastasis. With the help of UC Davis assistant professor Blain Christiansen, they also found that cells expressing more SOST induced significantly less osteolytic bone loss. These results provided strong evidence that SOST has an inhibitory effect on prostate cancer metastasis to bone.
Contact: Gabriela Loots (925) 423-0923 (loots1@llnl.gov).
Lawrence Livermore scientists have found that hydrogen-treated graphene nanofoam electrodes in lithium-ion batteries show higher capacity and faster transport. A paper on their research appears in the November 5, 2015, edition of Nature Scientific Reports. “The performance improvement we’ve seen in the electrodes is a breakthrough that has real-world applications,” says Jianchao Ye, a Livermore materials scientist who is lead author of the paper.
A lithium-ion battery is a rechargeable battery in which lithium ions move between the negative electrode to the positive electrode during discharge and recharge. The capacity, voltage, and energy density of lithium-ion batteries are ultimately determined by the binding between lithium ions and the electrode material. That binding can be affected by subtle changes in an electrode’s structure, chemistry, and shape.
To study the involvement of hydrogen and hydrogenated defects in the lithium storage ability of graphene, Livermore scientists applied various heat treatment conditions combined with hydrogen exposure and looked into the electrochemical performance of three-dimensional graphene nanofoam electrodes, which are comprised mostly of defective graphene. The team’s experiments and multiscale calculations show that low-temperature treatment of defect-rich graphene with hydrogen can improve rate capacity. Hydrogen reacts with the defects in the graphene, opening small gaps to facilitate easier lithium penetration, which improves the transport. Because hydrogen is most likely to bind near edges, lithium binding is enhanced in those areas, providing additional reversible capacity.
The Livermore team’s research suggests that controlled hydrogen treatment may be used as a strategy for optimizing lithium transport and reversible storage in other graphene-based anode materials such as those used in electric vehicles and aerospace technologies.
Contact: Jianchao Ye (925) 423-6696 (ye3@llnl.gov).
New research by Lawrence Livermore scientists and colleagues at the University of California at Santa Cruz, University of Colorado, and University of Kiel in Germany has revealed distinct differences in the ways plankton have responded to climate over the last thousand years. These results can be found in the November 26, 2015, edition of the journal Science Express.
Deep-sea corals act as living sediment traps, filtering out sinking organic matter that reaches them from the ocean surface before it is remineralized. That organic matter is known as export production. The components of phytoplankton organic matter are recorded in the growth bands of deep-sea coral skeletons. Thus a coral’s skeleton acts as a strip-chart reminder of what the coral has fed upon, enabling researchers to reconstruct the relative contribution of different phytoplankton groups to the export production back through time.
The researchers found that the North Pacific Subtropical Gyre—a system of ocean currents that is also the largest continuous ecosystem on Earth—has undergone major shifts in phytoplankton community composition associated with large-scale regional climate change. An increase in nitrogen-fixing cyanobacteria over the last 150 years has resulted in greater food production by phytoplankton, which are making their own nitrogen-based fertilizer out of dissolved nitrogen. However, as the oceans have warmed, the surface water of the gyre has become more stable and allows fewer nutrients from below—including nitrogen—to be incorporated into the surface layer, where phytoplankton need nitrogen to grow and continue taking up carbon from the atmosphere. Therefore, although phytoplankton may have inhibited rising carbon dioxide levels over the last 100 years, “we cannot expect this to be the case in the future,” says author Tom Guilderson. Climate change is predicted to continue to alter marine phytoplankton communities and affect productivity, biogeochemistry, and the efficacy of the biological pump.
Contact: Tom Guilderson (925) 422-1753 (guilderson1@llnl.gov).