Research suggests new model for cancer metastasis

Fallleaves

This is some freaky stuff (sounds like a horror movie)...talks about how some immune cells get tricked into helping cancer (but dendritic cells are smarter).

'Headley and colleagues in Krummel's lab injected melanoma cells into bloodstream of mice and tracked the arrival of these cancer cells in the lungs, where they observed a bizarre and macabre scene unlike anything they had imagined. The early invaders themselves were blown to bits by the power of the blood flowing by, but their shredded remains took on a life of their own.

These fragments, which Krummel calls "headless horsemen," crawl along the capillary walls and fly through the blood deeper into the lung. The researchers also observed immune cells, alerted to the hubbub, mobbing the zombie cancer fragments and gobbling them up. But these cellular first responders soon began to act very strangely, leaving the capillaries and appearing to create protective nests for future cancer cells within the tissue of the lung itself.'

"Not all immune cells are taken in by the zombie cancer particles, Krummel and colleagues have found. After injecting cancer cells into mice, the researchers observed several distinct waves of immune cells arriving in the lung. Many early-responding immune cells – such as monocytes and macrophages – go on to help later cancer cells get established. Dendritic cells, on the other hand, typically arrive late to the scene, but appear to recognize the cancer as a threat: After ingesting cancer cell particles, they travel to the mouse's lymph nodes and activate other immune cells capable of returning to the lung and attacking any incipient metastatic colonies.

This realization spurred a new hypothesis about why some invasive cancers take hold and others don't, Krummel said. "In a successful metastasis, we think there's an imbalance, where too many cells are getting programmed by the tumor to accept cancer cells as harmless, and too few are getting the message that these cells are dangerous or different."

http://medicalxpress.com/news/2016-03-cancer-metas...

JohnSmith

Good article.

What do these early cancer cells express that make immune system macrophages help them out?

Anytime I read about macrophages, I think of how Anti-CD47 therapies can trigger phagocytosis by macrophages by interrupting the CD47 "don't eat me" signal expressed by cancer cells.

Heidihill

Could lymphatic vessels be the key? Keep the lymph flowing and communications are more efficient, more cells get the message?

This article gives us the flip side of the video from the NIH blog. That one shows how the cancer cells escape into the bloodstream and this one shows how they "crawl through capillary walls" and go deeper into the lung.