By Lynne Friedmann

Lynne Friedmann

Reviving a theory first proposed in the late 1800s, scientists at the Salk Institute for Biological Studies have studied organ development in mice to unravel how breast cancers develop in humans. What they found were striking similarities between genetic signatures found in certain types of human breast cancer and those of stem cells in breast tissue in mouse embryos. These findings suggest that cancer cells subvert key genetic programs that guide immature cells to build organs during normal growth.

Stem cells in a healthy developing embryo have a “GPS system” to alert them about their position in an organ. The Salk finding points to a GPS system that is broken during cancer development. This may explain why stem-like cells are detected in breast cancers. Next step is to characterize the stem-like cells in certain forms of breast cancer to arrest their growth.

The findings appear in the journal Cell Stem Cell. http://bit.ly/AygIjG

Engineers build “no-waste” laser
Researchers from the UC San Diego Jacobs School of Engineering announce two noteworthy achievements in laser technology: the smallest room-temperature nanolaser to date and a highly efficient, “thresholdless” laser that funnels all its photons into “lasing” (the operation phase when laser light is produced) without any waste.

The two new lasers require very low power to operate, an important technological feat since lasers usually require greater and greater “pump power” to begin lasing as they shrink to nano sizes. Furthermore, the nanolaser designs appear to be scalable, meaning that they could be shrunk to even smaller sizes – an important feature that makes it possible to harvest laser light from even smaller nanoscale structures. The small size and extremely low power of these nanolasers could make them useful components for future optical circuits packed on tiny computer chips.

The work is reported in the journal Nature. News release at http://bit.ly/w5NdTf

Heart hormone helps shape fat metabolism
In addition to exercise, a study at Sanford-Burnham suggests that the heart plays a role in breaking down body fat. According to the research, hormones released by the heart stimulate fat-cell metabolism by turning on a molecular mechanism similar to what’s activated when the body is exposed to cold and burns fat to generate heat.

The metabolic effects caused by these heart hormones (so-called cardiac natriuretic peptides) depend largely on the ratio of two different kinds of receptors — message-receiving proteins — on the surface of fat cells.

In addition to providing a better understanding of the breakdown of fats, more information about how this system works could also give hope to patients suffering from cardiac cachexia, a severe body wasting that can occur in chronic heart failure. High levels of natriuretic peptides are characteristic of heart failure and are used as diagnostic markers of the severity of the disease.

The findings appear in the Journal of Clinical Investigation. http://bit.ly/A7cjMQ.

— Lynne Friedmann is a science writer.

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Research Report: Old theory pinpoints new targets to breast cancer