The most deadly aspect of cancer is its ability to spread, or metastasize. Cancer cells initially group together to form a primary tumor. Once the tumor is formed, cells may begin to break off from this tumor and travel through the blood stream or lymphatic system to other parts of the body. This process is metastasis. These cancer cells that travel through the body are capable of establishing new tumors in locations remote from the site of the original disease.
Researchers at Memorial Sloan-Kettering Cancer Center through a recent study have discovered a process called “self-seeding” that takes place in cancer cells.In this process they found that circulating cancer cells that detach from their primary site of origin and spread to other body parts, can also return back and grow in their tumor of origin.
Tumor growth can be enhanced by self-seeding by 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.
Study conducted in mice shows that self-seeding involves two distinct functions: the ability of a tumor to attract its own circulating progeny and the ability of circulating tumor cells to re-infiltrate the tumor in response to this attraction.Four genes have been identified by researchers that are involved in bringing about these functions: IL-6 and IL-8, which attract the most aggressive segment of the circulating tumor cells population, and FSCN1 and MMP1, which mediate the infiltration of circulating tumor cells into a tumor.
The process of self seeding has been displayed by circulating breast cancer cells where it was also identified that these cells have a pattern of gene expression which is similar to breast cancer cells that are capable of spreading to parts like lungs,brain and bones.Hence these circulating cells have a high tendency to metastasize these organs. Self-seeding has also been seen in cells of other cancers like colon cancer and melanoma.
Having discovered this process,therapies which are designed to interfere with this self-seeding process can be developed that would slow or even prevent progression of tumor according to the study’s senior author, Joan Massagué, PhD, Chair of the Cancer Biology and Genetics Program at Memorial Sloan-Kettering and a Howard Hughes Medical Institute investigator.
The study co-author Larry Norton, MD, Deputy Physician-in-Chief for Breast Cancer Programs at Memorial Sloan-Kettering says that the concept of self-seeding provides an insight into relationship between the tumor size, prognosis, and local relapse following seemingly complete removal of a primary breast tumor. “We know there is an association between large tumor size and poor prognosis. This was always thought to reflect the ability of larger cancers to release more cells with metastatic potential. But this association may actually be caused by the ability of aggressive cancer cells to self-seed, promoting both local tumor growth and distant metastases by similar mechanisms.”
“Posted via news provided by Eureka Alert a service of AAAS”