Hypoxia is a condition that leads to a lack of response to a wide variety of cancer therapies. Tumor hypoxia causes resistance to many cancer therapies, including radiotherapy and chemotherapy. Methods that increase the tumor’s oxygen pressure, such as hyperbaric oxygen therapy and microbubble infusion, are being used to improve response to current standard treatments. However, major obstacles remain, in particular the delivery of oxygen at the correct dose and with optimal pharmacokinetics.

In a new study, scientists at the University of Iowa used GeMs to deliver high levels of oxygen directly into tumors. Inspired by the foam on top of lattes, gummy bears, and Pop Rocks candies, scientists are creating new, biocompatible materials called gas-trapping materials, or GeMs, that could improve the effectiveness of chemotherapy and radiation for cancer treatment.

GeMs can significantly increase oxygen levels in solid tumors, making the cancer cells more susceptible to radiation or chemotherapy, according to a recent study. In addition, the increased oxygen levels seemed to enhance immunological reactivity, which is essential for eliciting an immune response to immunotherapy.

Byrne, UI assistant professor of radiation oncology and a member of the Holden Comprehensive Cancer Center at UI, said: “We’ve known for a long time that if you increase the amount of oxygen in a tumor, you can make it more responsive to radiation, certain chemotherapies, and possibly even immunotherapies.”

“However, the challenge was to deliver an effective dose of oxygen in a safe, controlled manner.”

“These GeMs are very simple, with only three ingredients: the gas, the foaming agents and the thickener. We use several unique, custom 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 sustained, controlled release of the gas.”

Scientists have created GeMs using a beating siphon, but they’ve reverse engineered them to accept different gases, including oxygen. They used safe, low-cost components in many processed foods to make the GeMs.

The amount of each component can be changed to control how much oxygen is released from the component. Byrne states that the translatability of the GeMs for cancer treatment is likely quite high, as they are made with safe and digestible components.

The ability to implant or inject GeMs directly into the tumor is an added advantage. The ability to deliver high drug concentrations with few adverse effects in the tumor has led to the increase in the intratumoral delivery of anticancer drugs over the past decade. The foams can be injected into challenging tumor sites for surgical treatment or removal.

Study first author Bi, a research scientist in Byrne’s lab, said: “One of the aspects of this project that got me excited was the combination of cancer biology principles with materials science to create something that can make an impact.”

Magazine reference:

  1. Jianling Bi, Emily Witt, et al. Inexpensive, high-pressure synthesized oxygen-scavenging materials to improve treatment of solid tumors. Advanced science. DOI: 10.1002/advs.202205995