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Insights on rare childhood disease

Children born with multiple hereditary exostoses (MHE) suffer from abnormal growths on their bones. A debilitating condition, MHE stunts body growth and can cause pain and disfigurement. And, if the protrusions are not surgically removed, there is a chance the bone growths could become cancerous.

Scientists have long known which genes are mutated in this rare disease, but not how the mutations lead to abnormal bone growth. The lack of an animal model has stymied MHE research efforts.

Now, researchers at Sanford-Burnham Medical Research Institute (Sanford-Burnham) and their colleagues have announced the creation of a mouse model that mimics the disease in humans. Already the new mouse model has answered some long-standing questions about MHE, and in the future it will provide a platform for screening potential therapies. The study appears in the Proceedings of the National Academy of Sciences. News release at

https://bit.ly/dg10F7

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Painkiller inhibits cancer

It’s been observed that people who regularly take non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin tend to have lower incidences of certain types of cancer. In a new study investigators at Sanford-Burnham Medical Research Institute (Sanford-Burnham) and their colleagues have figured out how one NSAID, called Sulindac, inhibits tumor growth. Sulindac is currently prescribed for the treatment of pain and fever, and to help relieve arthritis symptoms.

The study reveals that Sulindac shuts down cancer cell growth and initiates cell death by binding to nuclear receptor RXRa, a protein that receives a signal and carries it into the nucleus to turn genes on or off. RXRa normally suppresses tumors, but many types of cancer cells produce a truncated form of this nuclear receptor that does just the opposite.

This study showed that shortened RXRa enhances tumor growth by stimulating other proteins that help cancer cells survive.

Researchers found that Sulindac can be used to combat this deviant RXRa by switching off its pro-survival function and turning on apoptosis, a process that tells cells to self-destruct.

The study appears in the journal Cancer Cell. New release at

https://bit.ly/aIvr2I

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Unusual antibody against HIV

A team led by Scripps Research Institute scientists has determined the structure of an immune system antibody molecule (called PG16) that effectively acts against most strains of human immunodeficiency virus (HIV), the virus that causes AIDS.

PG16 is a rare, broadly neutralizing antibody isolated from an individual in Africa. Researchers used x-ray crystallography to reveal the active part of PG16’s antibody structure and found, among other things, a novel structure they call the “hammerhead” because it resembles a hammerhead shark. The studies of PG16 have revealed much about how neutralizing antibodies work and suggest possible mechanisms of action not usually seen in antibodies this effective against HIV.

Researchers hope to translate the insights gleaned from this study into the design of a promising AIDS vaccine candidate. The study appears in the journal Proceedings of the National Academy of Sciences (PNAS). News release at

https://bit.ly/dn5dhr

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Lynne Friedmann is a science writer based in Solana Beach.