Search Here

Researchers have discovered a signaling pathway in cancer cells that controls their ability to invade nearby tissues.

The study noted that to migrate from a primary tumor, cancer cells must first break through surrounding connective tissue called extracellular matrix (ECM). They do it by forming short-lived invadopodia - foot-like protrusions these cells use to invade. Invadopodia also release enzymes that degrade the ECM. 

The invading cancer cell relies on the cycle of invadopodium formation/disappearance to successfully travel from the tumor and enter nearby blood vessels to be carried to distant parts of the body, the press release added.

"We've known for some time that invadopodia are driven by protein filaments called actin," said study leader Louis Hodgson, Ph.D., assistant professor of anatomy and structural biology at Einstein in the press release. "But exactly what was regulating the actin in invadopodia was not clear."

Researchers used the self-devised fluorescent protein biosensor in highly invasive breast cancer cells that were taken from rodents and humans. According to the press release, they discovered that when an individual invadopodium forms and is actively degrading the ECM, its Rac1 levels are low; on the other hand, elevated Rac1 levels coincide with the invadopodium's disappearance. 

"So high levels of Rac1 induce the disappearance of ECM-degrading invadopodia, while low levels allow them to stay-which is the complete opposite of what Rac1 was thought to be doing in invadopodia," said Dr. Hodgson.

"Rac1 inhibitors have been developed," Dr. Hodgson added in the press release, "but it wouldn't be safe to use them indiscriminately. Rac1 is an important molecule in healthy cells, including immune cells. So we'd need to find a way to shut off this signaling pathway specifically in cancer cells."

The research has been published in the online edition of Nature Cell Biology.