Understanding how cancers spread

Most cancer deaths are caused by tumor metastasis, yet the exact mechanism is unknown. New work from MIT reveals some critical molecules involved.
Written by Janet Fang, Contributor

About 90 percent of cancer deaths are caused by tumor metastasis – or when cancer cells break free and spread to other parts of the body. Yet, we don’t have an exact understanding of the mechanism that causes that.

So, how do tumor cells detach from the elements that normally hold tissues in place, and how do they reattach themselves someplace new? MIT News asks.

Cells in our body are tethered to a structural support system called the extracellular matrix, which also helps regulate cell behavior. On the surface of cells, proteins called integrins form the anchors that hold the cells in place; when cancer cells metastasize, these anchors let go.

MIT researchers led by Sangeeta Bhatia compared the adhesion properties of four types of cancer cells: primary lung tumors that later metastasized, primary lung tumors that did not metastasize, metastatic tumors that migrated from the lungs to nearby lymph nodes, and metastatic tumors that traveled to more distant locations such as the liver.

  1. They exposed each type of cell to hundreds of proteins found in the extracellular matrix (pictured).
  2. Then they measured how well cells from each tumor type bound to the protein.
  3. One pair of extracellular matrix molecules that metastatic tumors stuck to especially well was fibronectin and galectin-3, both made of proteins that contain or bind to sugars.

In fact, the more aggressive the metastasis, the more galectin-3 was present. Its accumulation appears to help tumor cells colonize new sites.

This offers new ways to block metastasis by focusing on a specific protein-protein or protein-sugar interaction -- rather than gene mutation. The research team is now developing new candidate therapeutics aimed at inhibiting those interactions.

The work was published in Nature Communications last week.

[Via MIT News]

Image: selective adhesion from N.E. Reticker-Flynn et al.

This post was originally published on Smartplanet.com

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