Currently, there is no reliable non-invasive test for ovarian cancer, but Notre Dame’s Crislyn D’Souza-Schorey hopes her work may one day change that, and perhaps even lead to a treatment. About a year ago the Notre Dame associate professor of biological sciences and her colleagues identified a class of tiny saclike structures filled with a certain mix of proteins and nucleic acids that are released by a wide spectrum of tumor cell types, including ovarian cancer cells.
Significantly, the formation and release of these sacs seems to be a key step in the cancer’s invasion of healthy tissue. These “microvesicles” are filled with protease molecules able to degrade the matrix surrounding the tumor, creating a path of least resistance for the cancer cells. “We believe these sacs also may be able to fuse with other cells in the tumor microenvironment, triggering alterations that enable metastasis,” D’Souza-Schorey says.
“If we could identify the mechanisms by which these processes occur, potentially that could help with design of more effective therapies,” she adds. Simply put: Stop the fusion. Stop the cancer.
Additionally, the ND biologist says these tumor-derived membrane sacs might be the basis for a reliable diagnostic test because they can be detected in blood, urine and ascites, the bodily fluid which accumulates in the abdomen of an ovarian cancer patient.
“There appears to be a direct correlation between the concentration of these shed structures and the stage of the disease,” D’Souza-Schorey notes. As the tumor becomes more invasive, more of these particular microvesicles are shed.
The Notre Dame scientist says she is now focused on understanding how the tiny membranes are formed, how the matrix-degrading protein molecules are packaged within the membranes and what cellular factors govern the process.
Her lab is collaborating with local oncologists who specialize in ovarian cancer care. “Our goal is to identify the complete protein composition of these structures in hopes of identifying molecular signatures or ‘fingerprints’ that might tell us something about the tumor from which it derived,” she says. Such information could offer a way to individualize therapy specific to the precise form of cancer that a person may have.
D’Souza-Schorey notes that cancer is not a single disease but actually a group of diseases characterized by a variety of aberrant cellular conditions initiated by an equally wide array of causes. Hence, the focus on individualized therapy.
While the Notre Dame biologist and her lab have focused on the implications of their work for ovarian cancer, she says that since the same type of microvesicles are released by breast, prostate and colon cancers, they might lend themselves to diagnostic and therapeutic approaches for those cancers as well.
John Monczunski is an associate editor of Notre Dame Magazine. Email him at jmonczun@nd.edu.