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Archive - Feb 11, 2013

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Researchers Discover “Achilles’ Heel” for Lymphoid Leukemia

An international research team coordinated at the IRCM (Institut de recherches cliniques de Montréal) has found a possible alternative treatment for lymphoid leukemia. Led by Dr. Tarik Möröy, the IRCM’s President and Scientific Director, the team discovered a molecule that represents the disease’s “Achilles’ heel” and could be targeted to develop a new approach that would reduce the adverse effects of current treatments such as chemotherapy and radiation therapy. The study’s results were published online on February 11, 2013 in Cancer Cell. The researchers’ results have direct implications for the treatment of acute lymphoblastic leukemia (ALL), one of the four most common types of leukemia. ALL is a cancer of the bone marrow and blood that progresses rapidly without treatment. Current treatments consist of chemotherapy and radiation therapy, which are both highly toxic and non-specific, meaning that they damage healthy cells as well as tumor tissues. “Even when effective, patients can suffer dramatic side effects from these treatments,” says Dr. Möröy, who is also Director of the Hematopoiesis and Cancer research unit at the IRCM and corresponding author of the study. “Therefore, they would directly benefit from an improved therapy that could reduce the necessary dose of radiation or chemotherapy, and thus their side effects, while maintaining the treatments’ efficacy. Therapies that target specific molecules have shown great promise. This is why, for the past 20 years, I have been studying a molecule called Gfi1, which plays an important role in the development of blood cells and cancer.” When normal cells are transformed into tumor cells, the body responds by activating a tumor suppressor protein that induces cell death.

Engineers Design Genetic Circuits That Remember Their History

MIT engineers have created genetic circuits in bacterial cells that not only perform logic functions, but also remember the results, which are encoded in the cell’s DNA and passed on for dozens of generations. The circuits, described online on Februay 10, 2013 in Nature Biotechnology, could be used as long-term environmental sensors, efficient controls for biomanufacturing, or to program stem cells to differentiate into other cell types. “Almost all of the previous work in synthetic biology that we’re aware of has either focused on logic components or on memory modules that just encode memory. We think complex computation will involve combining both logic and memory, and that’s why we built this particular framework to do so,” says Dr. Timothy Lu, an MIT assistant professor of electrical engineering and computer science and biological engineering and senior author of the Nature Biotechnologypaper. Lead author of the paper is MIT postdoc Dr. Piro Siuti. Undergraduate John Yazbek is also an author. Synthetic biologists use interchangeable genetic parts to design circuits that perform a specific function, such as detecting a chemical in the environment. In that type of circuit, the target chemical would generate a specific response, such as production of green fluorescent protein (GFP). Circuits can also be designed for any type of Boolean logic function, such as AND gates and OR gates. Using those kinds of gates, circuits can detect multiple inputs. In most of the previously engineered cellular logic circuits, the end product is generated only as long as the original stimuli are present: Once they disappear, the circuit shuts off until another stimulus comes along. Dr. Lu and his colleagues set out to design a circuit that would be irreversibly altered by the original stimulus, creating a permanent memory of the event.