Lab discovers common blood protein promotes cancer growth

Halifax, NS – Researchers at Dalhousie Medical School have identified a key mechanism of cancer metastasis that could lead to blocking tumour growth. The discovery was published in the November 1 issue of Cancer Research, a journal of the American Association for Cancer Research.

Dr David Waisman and his team discovered blood cells called macrophages carry a protein called S100A10. Macrophages travel into tumours using this protein and facilitate cancer growth. How macrophages moved through tissues and into tumours had been a mystery until this discovery.

“We used to think that the only cells that mattered in a tumour were the cancer cells, and that’s it, but now we are beginning to see that other cells must collaborate with cancer cells to drive tumour growth and permit an evolution of the cancer cells into metastatic cells,” said Dr Waisman, professor in the departments of Biochemistry & Molecular Biology and Pathology, and Canada Research Chair in Cancer Research at Dalhousie. “This change is what causes poor prognosis and ultimately what kills the patient.”

Macrophages chew their way through healthy tissues, enter tumours using their S100A10, and then combine with cancer cells inside of the tumours. This causes tumours to grow and the cancers to spread.

“We found that the protein, S100A10, acts like a pair of scissors on the outside of the macrophages that empowers the macrophages with the ability to chew their way through tissues and enter the tumour site where they release substances that stimulate cancer cell growth and metastatic evolution,” he added.

He explained that theoretically, blocking either the macrophages or S100A10 chemically could slow, or even stop, tumour growth.

“The next step is to figure out exactly how S100A10 functions as a molecular scissor and also to identify pharmaceutical agents that can block the action of S100A10, thereby preventing the movement of macrophages into tumours. By understanding exactly how S100A10 works at the molecular level, it may even be possible to design agents that block its activity,” he said.

Story originally reported by Allison Gerrard, Dalhousie Medical School.