Survival rates for metastatic (or advanced) breast cancer are lower than other breast cancer stages and a key focus area for NBCF research investment. However, scientists have discovered that metastasis is a highly coordinated and non-random process, with the involvement of specific cell types. This means that a better understanding of the process could lead to improved treatment options in the future.
Associate Professor Andreas Möller, from the QIMR Berghofer Medical Research Institute in Brisbane, and Associate Professor Belinda Parker, from the Peter MacCallum Cancer Centre in Melbourne, led teams investigating the ways that cancer cells communicate with each other and their environment to promote deadly spread. The team of A/Prof Möller is particularly interested in exosomes, which are small vesicles excreted by cancer cells as they grow and spread.
A new study by the investigators, published in the prestigious journal Nature Communications, has now shed more light on the role of these exosomes in cancer metastasis. The study used human breast cancer cells, mouse models and human blood plasma samples, from 6 healthy women and 12 with breast cancer. The study included samples from women with multiple types of breast cancer (luminal, HER2+ and triple-negative), and all had late stage disease (stage IV).
Using a range of laboratory techniques, the researchers discovered that immune proteins called cytokines bind to the outer surface of exosomes. This leads to an accumulation of exosomes in the tissues and organs, which changes the microenvironment around tumours and leads to a higher risk of metastasis.
“Once spread of breast cancers to other sites in the body occurs, it is often too late to intervene and controlling these advanced cancers is very difficult. This study offers an opportunity to predict those patients most at risk of cancer spread, allowing earlier therapeutic intervention to prevent the deadliest stages of disease” says Associate Professor Parker.
The teams hope that the discovery of these cytokine-exosome interactions may lead to a better understanding of the mechanism of metastasis, and a possible treatment to halt the process in the future.
“Now that we know how the cancer sends exosome messages to specific tissues, the next step will be identifying how to interrupt those and reactivate the anti-cancer behaviour of those tissues” Associate Möller states.
This work was funded by a NBCF grant to Prof Möller and A/Prof Parker.