Lattes and Candy Inspire New Material for Better Cancer Treatment

A reverse-engineered whipping siphon dispenses gas-entrapping foam in the University of Iowa lab of James Byrne. Byrne and team focus on the use of molecular gastronomical techniques to create novel materials for the treatment for cancer. Credit: University of Iowa Health Care

Nature is a popular inspiration for scientists, who often take characteristics from plants and animal species and apply it to their everyday work. Gecko-inspired adhesives is a well-known example, as well as insect-mimicking robotics.

Less often do scientists find inspiration in their local Starbucks—unless you are Jianling Bi and James Byrne. In a new study, the University of Iowa researchers detail how they were inspired by the foam on top of lattes, gummy bears and even Pop Rocks candies when creating new, biocompatible materials to improve the effectiveness of chemotherapy and radiation.

Oxygen-starved

Tumor hypoxia drives resistance to many cancer therapies, including radiotherapy and chemotherapy. Several methods that increase oxygen levels in tumors or exploit low tumor oxygen levels have been shown to improve responses to current standard-of-care therapies in recent years. However, key obstacles still exist, including how to deliver an effective dose of oxygen in a safe, controlled fashion.

That’s where Bi and Byrne’s new material comes into play.

The materials—known as gas-entrapping materials, or GeMs—can be formulated as foams, solids, or hydrogels. They are designed to carry high concentrations of a variety of therapeutic gases directly into tissues, including tumors.

“These GeMs are very simple, with just three ingredients: the gas, the foaming agents and the thickening agent,” said Byrne. “We use several unique, custom-built pressurized systems to incorporate high concentrations of gas into small volumes of these biocompatible materials, which can be injected or implanted into tissues and allow for prolonged, controlled release of the gas.”

The foam GeMs are created using a whipping siphon—essentially the same device baristas use to make foams on lattes—but reverse-engineered to accept various gases, including oxygen. The whipping siphon made it possible to evaluate different foaming agents with tunable material properties. While a broad array of natural polymers was tested for their gas entrapment capabilities, the researchers say those of natural carbohydrate-based materials were the highest performing—and also the most similar to the manufacture process of the candy Pop Rocks.

In the study, published in Advanced Science, the researchers tested the effectiveness of GeMs in combination with chemotherapy and radiation in mouse models of prostate cancer and a type of sarcoma.

For mice with sarcoma tumors, GeM plus radiation inhibited tumor growth and extended life span from a median time of 13 days (no treatment) to 25 days. Similarly, prostate tumor growth in GeM plus radiation-treated mice was significantly slower compared with radiation-only treated mice and no treatment control counterparts. According to the study, life span was extended from a median of 20 days (no treatment) to 37 days.

The researchers also tested two chemotherapeutic agents—tyrosine kinase inhibitors cabozantinib and sorafenib—to determine the effectiveness of GeM as a combination strategy. In mice bearing prostate tumors, the GeM plus cabozantinib treatment significantly inhibited tumor growth relative to cabozantinib treatment alone. Similar results were observed for GeM plus sorafenib.

“[Our study] showed that administering oxygen through a GeM approach increases intratumoral oxygen levels,” write the researchers. “Our preclinical results demonstrate that, in two distinct animal models of cancer, the delivery of oxygen through these materials improved responses to radiation and chemotherapy.

Indeed, the ability to implant or inject GeMs directly into a tumor is a huge advantage. Intratumoral delivery of cancer therapies has been an active research area over the past decade, as the technique can deliver a high concentration of drugs directly inside the tumor with low side effects. In this case, the foam GeM designed by the Iowa team can be injected into areas of the tumor that are harder to treat or remove by surgery.

Beyond chemotherapy and radiation, the researchers also noted that the increased oxygen levels appeared to improve immune reactivity—which is a key aspect to generating a response to cancer immunotherapy treatment.

The scientists say translation of the approach from mice to human use should be rapid, as the GeMs are manufactured with safe and edible components. Additionally, the lab’s whipping siphons use the same Generally Recognized as Safe (GRAS) components found in many processed foods.

“One of the aspects of this project that really excited me was the combination of cancer biology principles with material science to create something that can be really impactful,” said Bi.