Proteases play vital roles in most stages of cancer progression, including cell growth, the formation of new blood vessels, and metastasis. Illustration courtesy of Thomas Pashuck.

Proteases are enzymes that act as catalysts in chemical reactions that break down proteins into peptides and amino acids. They play an important role in many physiological processes, such as the development and regeneration of tissue and the progression of cancer, including migration and metastasis.

Funded by a $400,000 grant from the National Institutes of Health, E. Thomas Pashuck (pictured), an assistant professor of bioengineering, will conduct a study to visualize the activity of proteases in cancer models. The findings could improve our understanding of cancer progression and support the development of better treatments.

E. Thomas PashuckQuantifying the activities of proteases within tissues is challenging and current options are limited, says Pashuck, who will use novel biomolecular conjugates that are sensitive to proteases to enable visualization of proteolytic activity in tumors.

“We will use confocal microscopy to visualize our model tumors and understand how cancer cells modify their local environment, and also how they modulate the proteolytic activity of other cell types within the tumor,” he says.

While other systems that enable the visualization of protease activity exist, Pashuck’s method was designed to have lower background fluorescence (increasing imaging quality) and enable visualization of multiple proteases at the same time.

Pashuck is working with PhD student Sam Rozans to develop protease-responsive conjugates. They will incorporate them into hydrogels, including those containing both cancerous and noncancerous cells, and visualize spatiotemporal protease activity in model tissue to better understand metastatic processes.

The approach, according to the project summary, can be easily adapted by other labs, used for many proteases, and incorporated into most biomaterial systems. “Since proteases catalyze the cleavage of a peptide bond, they are especially useful for making stimuli-responsive therapies. Thus this research can help researchers across disciplines develop more effective biomedical interventions.”

Cancer is the second leading cause of death in the United States, and about 40 percent of people will be diagnosed with cancer at some time in their lives.

“Understanding the complex interactions that occur within the tumor microenvironment is crucial for creating more effective therapies to inhibit the processes that lead to poor treatment options,” Pashuck says.

Drugs targeting protease activity have entered clinical trials but, so far, have not been successful. New protease therapies that have improved enzyme specificity have been developed.

“Increasing our understanding of protease activity in the tumor microenvironment is needed to bring such promising drugs to the clinic,” he says.