A new study found that a molecule thousands of times smaller than a gene is able to kill medulloblastoma, the most common childhood brain cancer.

This tiny molecule, named MiR-584-5p, is quite efficient in its action. MiR-584-5p sensitizes the cancer to chemotherapy and radiation, making it plausible to treat the tumors with one-tenth the dose that is currently required, said the senior author.

"Currently we barrage the brain with radiation and chemo, and patients have poor quality of life," the senior author said. "Using this molecule, we could dial down those therapies considerably, by 90 percent. That's exciting."

MiR-584-5p is at very low levels or absent altogether in medulloblastoma. Increasing it to the amount found in healthy cells robs the cancer of mechanisms it uses to survive, studies show. "This can serve as a potent therapeutic for treating cancer," the author said. The journal Nature Communications published the findings.

The other excitement about MiR-584-5p is that it is normally present at high levels in brain cells and not so in other tissues, the senior author said. Therefore, when it is used in the brain as therapy to kill tumors, it will have negligible effects on the healthy cells because those cells have seen it before. "They may not treat the molecule as something foreign," the senior author said. A future therapy based on the molecule should be well-tolerated, he said.

A big challenge for treating brain cancer patients is the inability of cancer drugs to cross the blood-brain barrier, a protective mechanism that holds up brain cancer therapies. Because it is so petite, MiR-584-5p may be able to cross this barrier, which is leaky in some medulloblastoma patients. In the future, the molecule may be delivered using a nanoparticle carrier.

Aside from medulloblastoma, the properties of MiR-584-5p make it an excellent drug candidate for treatment of glioblastoma, an aggressive and lethal adult brain cancer, the senior author said.

https://news.uthscsa.edu/tiny-molecule-has-big-effect-in-childhood-brain-tumor-studies/

https://www.nature.com/articles/s41467-018-06808-8

http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Fmir-584-5p-potentiates&filter=22