Bacterium could influence cancer spread

New research by La Trobe University scientists has shown how a mycoplasma could facilitate the development of inflammatory disease and cancer.

The work, led by Dr Amber Gomersall and her supervisor, Professor Roger Parish, was reported recently in the international journal of the US-based Public Library of Science, PLOS ONE.

The origins of the study go back more than 25 years when Professor Parish – then working at the University of Zurich – discovered a protein on the surface of cells grown in culture which caused them to invade groups of other cells. The protein was named p37.

It turned out the cell cultures had been infected with Mycoplasma hyorhinis and the p37 protein was located on the surface of the mycoplasma cells.

Association with wide range of disease

'We discovered the p37 protein was part of a system transporting molecules into the mycoplasma cell,' Professor Parish said.

Mycoplasma are simple bacteria that lack a cell wall. There are more than one hundred species of mycoplasmas.

Mycoplasma hyorhinis is one of the four mycoplasma species that have been found associated with gastric, colon, ovarian, oesophageal, lung, breast and brain cancers in humans. It has also been linked to arthritis in some animals.

The La Trobe discovery follows recently published research from Peking University that reported the presence of the p37 protein in human gastric cancer was associated with metastasis and predicted poor patient survival.

Rapid gene activation

Dr Gomersall discovered that when she added purified p37 to cells grown in culture, the activities of a number of genes involved in inflammation as well as cancer development and metastasis were rapidly stimulated, some by 100-200 fold.

'We also found that the p37 protein binds to a protein on the surface of those cells, known as the TLR4 receptor. Specific proteins on the surface of certain bacteria, such as helicobacter (which is associated with stomach cancer), plus several viral proteins are also known to bind the TLR4 receptor and activate the production of pro-inflammatory molecules.

'Our results indicate Mycoplasma hyorhinis infection might – via p37 – play a role in the development of inflammatory diseases and cancer,' Dr Gomersall said.

Link with Sean Connery film

Professor Parish said the original research in his Zurich lab resulted in four international scientific papers. Subsequently, the p37 protein has been studied in many other laboratories around the world.

The new paper identifies a mechanism by which mycoplasma infection can influence human and animal cells.

In a novel twist, reports of the original discovery of p37 are believed to have inspired the film, Medicine Man.

In the film, actor Sean Connery played an eccentric scientist working deep in the Amazonian jungle who isolated so-called 'p37' from a plant in a fictional quest to cure cancer.

'Mycoplasma hyorhinis is certainly not a plant, and p37 is not a cancer cure, but this research shows the mechanism by which this type of bacterial infection could facilitate cancer development,' Professor Parish concluded.

Media contact:  Ernest Raetz 041 226 1919

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