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The Bacteria that Promote Cancer

Microscopy imaging of metastatic cancer cells. Credit: drimafilm/adobe

Microscopy imaging of metastatic cancer cells. Credit: drimafilm/adobe

By Amber Gomersall & Roger Parish

A bacterial protein can trigger inflammation and facilitate the progression of cancer.

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More than 25 years ago at the University of Zurich, Roger Parish and his colleagues identified a protein on the surface of mouse fibroblast cells that dramatically changed the normal behaviour of the cells. Generally, when fibroblast cells collide they change their direction of movement and retract from one another. Loss of this contact inhibition helps to drive invasion in cancer.

The fibroblasts displayed normal contact inhibition when the protein was blocked with a monoclonal antibody. However, the cells completely lost contact inhibition when the protein was not blocked.

This protein, named p37, is located on the surface of the bacterium Mycoplasma hyorhinis, where it forms a complex with two other proteins located in the outer membrane of the bacterium. The three proteins constitute a high-affinity transport system that the mycoplasma cells employ to take up molecules such as nutrients.

Mycoplasmas are minute bacteria that lack a cell wall. Several species cause inflammatory diseases in humans. M. pneumonia, for example, causes atypical pneumonia while M. genitalium gives rise to pelvic inflammatory diseases. M. hyorhinis is often present in the respiratory tract of young pigs and causes severe arthritis when they experience stress or a concomitant infection.

Evidence began to accumulate that p37, and hence M. hyorhinis, was associated...

The full text of this article can be purchased from Informit.