Scientists discover new nanoparticle, dubbed exomeres

A new cellular messenger discovered by Weill Cornell Medicine scientists may help reveal how cancer cells co-opt the body's intercellular delivery service to spread to new locations in the body. 

In new paper the scientists show that a cutting-edge technique called asymmetric flow field-flow fractionation (AF4) can efficiently sort nano-sized particles, called exosomes, that are secreted by cancer cells and contain DNA, RNA, fats and proteins. This technology allowed the investigators to separate two distinct exosome subtypes and discover a new nanoparticle, which they named exomeres.

"We found that exomeres are the most predominant particle secreted by cancer cells," said senior author Dr. David Lyden, the Stavros S. Niarchos Professor in Pediatric Cardiology, and a scientist in the Sandra and Edward Meyer Cancer Center and the Gale and Ira Drukier Institute for Children's Health at Weill Cornell Medicine. "They are smaller and structurally and functionally distinct from exosomes. Exomeres largely fuse with cells in the bone marrow and liver, where they can alter immune function and metabolism of drugs. The latter finding may explain why many cancer patients are unable to tolerate even small doses of chemotherapy due to toxicity."

Exomeres clock in at less than 50 nanometers in diameter, compared with small exosomes (Exo-S), which range from 60 to 80 nanometers in diameter, and large exosomes (Exo-L), which are 90 to 120 nanometers in diameter. Exosomes and exomeres also have different biophysical characteristics, such as stiffness and electric charge, that likely affect their behavior in the body.