Small RNAs can prevent spread of bre...( Howard Hughes Medical Institute rese...),Health

Howard Hughes Medical Institute researchers have identified small pieces of ribonucleic acid (RNA) that suppress the spread of breast cancer to the lungs and bone. The new research shows that the most invasive and aggressive human breast cancer tumors are missing three critical microRNA molecules. When the researchers put those molecules back into human breast cancer tumors in mice, the tumors lost their ability to spread.

The tiny RNAs prevent the spread of cancer by interfering with the expression of genes that give cancer cells the ability to proliferate and migrate, said senior author Joan Massagu, a Howard Hughes Medical Institute researcher at Memorial Sloan-Kettering Cancer Center.

The researchers said their new research findings add to the growing number of cellular targets for drugs designed to prevent breast cancer metastasis. The scientists are also optimistic that their work could spur the development of new clinical tests to assess the likelihood that breast tumors will metastasize. Metastasis of breast cancer is the leading cause of death from the disease.

Metastasis occurs when cells from a primary tumor break off and invade another organ. It is the deadliest transformation that a cancer can undergo, and therefore researchers have been looking for specific genes that propel metastasis. If they can identify distinctive metastatic gene programs for different cancers, it may be possible to slow or halt metastases by targeting the proteins produced by those genes.

Massagu, his postdoctoral fellow Sohail Tavazoie, and colleagues at Sloan-Kettering, published their findings in the January 10, 2008, issue of the journal Nature.

In the experiments reported in Nature, the researchers explored the role that microRNAs play in controlling the expression of genes that trigger the spread of breast cancer. MicroRNAs, which are no more than 20-22 nucleotides in length, play an important role in development, cancer, stress responses and viral
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