Aspirin and other household drugs help restrict supply lines of cancer

Scientists have discovered how common drugs such as aspirin help to contain tumours. Flickr/Clyde Bentley
Common household drugs such as aspirin help to contain certain types of tumours by tightening their lymphatic vessel supply lines, new research has found.

Doctors have long observed the impact of non-steroidal anti-inflammatory drugs such as aspirin on cancer, but without understanding how the process worked.

Researchers from the Tumour Angiogenesis Program at the Peter MacCallum Cancer Centre have now identified a link between the drugs and the ability for tumours to spread in the body. Their discovery is published today in the cancer biology journal Cancer Cell.

“We’ve known that tumours actively secrete a range of proteins and compounds, called growth factors, to attract blood and lymphatic vessels from within their immediate vicinity, enabling them to flourish and metastasise, or spread,” said Associate Professor Steven Stacker, senior author and co-leader of the Tumour Angiogenesis Program.

“In this research we have discovered that a gene (pgdh) links these growth factors to the prostaglandin cellular pathway - the pathway that can cause inflammation and dilation of vessels throughout the body.

"Basically, the growth factors released by tumours also encourage nearby collecting lymphatic vessels to widen, increasing the capacity for these "supply lines” to act as more effective conduits of cancer spread.“

Non-steroidal anti-inflammatory drugs typically act to target this pathway, and in doing so they are "effectively tightening a tumour’s supply lines and restricting the transport of cancer cells to the rest of the body”, said Dr Tara Karnezis, who was the lead author with Dr Ramin Shayan at Peter MacCallum Cancer Centre.

The drugs could help contain many solid epithelial tumours, including breast and prostate cancer, which affect large numbers of Australian men and women, Dr Karnezis said.

They could also be used in an early warning system - before the metastasis of a primary tumour.

“Doctors may be able to analyse a tumour for signs that prostaglandin pathways are being influenced, evidence that the tumour may be preparing to metastasise, and then alter patient treatment accordingly,” says Dr Karnezis.

Dr Ian Olver, a Clinical Professor of Oncology at Cancer Council Australia, said the finding provided important information about how cancers influenced the lymphatic system, which is one of the major pathways by which they spread.

“The practical application of this information is that knowing the mechanism provides a target for preventing cancers spreading,” Professor Olver said.

“In this case part of the pathway can be blocked by non-steroidal anti-inflammatory drugs such as aspirin. There have been several papers recently showing that people who take aspirin are at lower risk of being diagnoses with several cancers, this paper sheds light on a possible mechanism for this.”