A 'self-seeding' mechanism of cancer cells, which appears to play a critical role in tumour progression has been identified by scientists from Memorial Sloan-Kettering Cancer Centre.
Cancer progression is commonly thought of as a process involving the growth of a primary tumour followed by metastasis, in which cancer cells leave the primary tumour and spread to distant organs.
The new study shows that cancer cells can return to and grow in their tumour of origin, a process called "self-seeding."
It can enhance tumour growth through the release of signals that promote angiogenesis, invasion, and metastasis.
"Our work not only provides evidence for the self-seeding phenomenon and reveals the mechanism of this process, but it also shows the possible role of self-seeding in tumor progression," said the study's first author Mi-Young Kim, PhD, Research Fellow in the Cancer Biology and Genetics Program at Memorial Sloan-Kettering.
According to the research, which was conducted in mice, self-seeding involves two distinct functions: the ability of a tumour to attract its own circulating progeny and the ability of circulating tumour cells to re-infiltrate the tumor in response to this attraction.
The investigators identified four genes that are responsible for executing these functions: IL-6 and IL-8, which attract the most aggressive segment of the circulating tumour cells population, and FSCN1 and MMP1, which mediate the infiltration of circulating tumor cells into a tumor.
The findings also show that circulating breast cancer cells that are capable of self-seeding a breast tumour have a similar gene expression pattern to breast cancer cells that are capable of spreading to the lungs, bones, and brain, and therefore have an increased potential to metastasize to these organs.
"These results provide us with opportunities to explore new targeted therapies that may interfere with the self-seeding process and perhaps slow or even prevent tumor progression," said the study's senior author, Dr Joan Massague, Chair of the Cancer Biology and Genetics Program at Memorial Sloan-Kettering and a Howard Hughes Medical Institute investigator.
The study appears in journal Cell.