A team of bioengineers and bioinformaticians at the University of California San Diego have discovered how the environment surrounding a tumor can trigger metastatic behavior in cancer cells. Specifically, when tumor cells are confined in a dense environment, the researchers found that they turn on a specific set of genes and begin to form structures that resemble blood vessels.
In the past, physicians observed these blood vessel-like structures in the clinic—a phenomenon called vascular mimicry, which is associated with some of the most aggressive types of cancers. But they didn’t understand what caused this transformation.
The study adds to researchers’ knowledge of how the metastatic process may be initiated. “We are good at targeting tumor growth, but we do not know enough about metastasis,” said Stephanie Fraley, a professor of bioengineering at the University of California San Diego and the leader of the study.
Metastatic spread of tumor cells from one location in the body to another is the cause of 90 percent of cancer-related deaths. The set of genes that the researchers discovered, called a gene module, was able to predict patient life expectancy and whether tumors will metastasize across nine types of cancer, including breast, lung, pancreatic, and kidney cancers.
This gene module could be used to help determine whether patients are suffering from an aggressive type of cancer and inform the decisions patients and their physicians make when choosing specific therapies.
Researchers detail their findings in the Nov. 21 issue of Nature Communications.
The researchers were able to make their observations by placing the malignant cells in a custom 3D collagen matrix that they built. They found that the cells turned into structures that mimic blood vessels when surrounded by the matrix made of short fibers and small pores (as opposed to long fibers and large pores) and that this phenomenon was independent of other physical features of the matrix such as stiffness. This finding came as a surprise.