We found that aggressive melanoma cells could alter their environment and cause other less aggressive melanoma cells to act more aggressively

Dr Richard Seftor

And when less aggressive cancers come across it, they too can become much more threatening.

The environment around and between cells is known as the extracellular matrix and is full of molecules that play important roles in how tissues look and behave.

Researchers from the University of Iowa examined the impact of melanoma (skin cancer) cells on this environment.

They found that highly aggressive melanoma cells interact with this matrix differently than less aggressive melanoma cells.

Diagnosis and treatment

These differences may have important implications for the diagnosis and treatment of melanoma, as well as other types of aggressive cancers.

The researchers found that aggressive melanoma cells lay down a molecular track as they interact with their extracellular matrix.

These tracks appear to contain information and cues which, like bread crumbs on a path, contain information and directions that can be interpreted by less aggressive tumour cells.

These cues may persist in the matrix long after the aggressive tumour cells have moved on and then cause less aggressive cells, which move into this area, to become more aggressive.

Researcher Dr Richard Seftor said: "We found that aggressive melanoma cells could alter their environment and cause other less aggressive melanoma cells to act more aggressively."

Remodel

Cells remodel their extracellular environment by both knocking down and building up the physical structure they live in.

The interplay of building up and breaking down the extracellular matrix by cells plays a major role in how wounds heal, how cancer spreads through the body (metastasis) and how the body deals with inflammation.

Two types of protein play a particularly important role in this process. They are laminins and matrix metalloproteinaes (MMPs).

The researchers found that aggressive tumours cells were much more likely to produce particular types of these two proteins that react together to produce a trail of laminin fragments through the extracellular matrix.

It seems that these fragments enable the aggressive cells to spread themselves around the body more easily by mimicking cells found in the blood vessels.

When this chemical cocktail was blocked the tumour cells were unable to engage in this form of mimicry.

However, it was seen among less aggressive melanoma cells put onto the matrix for only a short period.

Lead researcher Dr Mary Hendrix said it might be possible to modify the extracellular matrix to stop tumour cells from proliferating.

The research is published in the journal Cancer Research.