Mouse study finds extra oxygen may spur tumor-fighting cells

Cancer cells
Electron microscopic image of a single human lymphocyte. Credit: Dr. Triche National Cancer Institute

A provocative study in mice suggests something as simple as breathing in extra oxygen might give immune cells a boost in attacking cancer.

The often can spot and destroy before they grow into cancer. But when tumors manage to take root, they put up defenses to block new immune attacks. Wednesday's study takes aim at one of those shields.

With the extra oxygen, "you remove the brake pedal" that cancer can put on tumor-fighting immune cells, said Michail Sitkovsky, director of the New England Inflammation and Tissue Protection Institute at Northeastern University, who led the work.

Here's what happens: Tumors can grow so rapidly that they outpace their blood supply, creating a low-oxygen environment. The lack of oxygen in turn spurs to produce a molecule called adenosine, which essentially puts nearby tumor fighters called T cells and to sleep, explained pharmacologist Edwin Jackson of the University of Pittsburgh, who co-authored the study.

Lots of research is under way to develop drugs that could block the adenosine effect. But Sitkovsky's team wondered if just getting more oxygen to an oxygen-starved tumor could strip away that defense.

So they put mice with different kinds of lung tumors inside chambers that mimic what's called supplemental . Air is about 21 percent oxygen, but hospitals can give patients concentrations of 40 percent to 60 percent oxygen through masks to treat various disorders.

Mouse study finds extra oxygen may spur tumor-fighting cells
Tumors residing in a hypoxic or low-oxygen environment exploit the signaling molecule adenosine to block activation of cancer-killing immune cells. Credit: C. Bickel/Science Translational Medicine

The extra oxygen changed the tumor's environment so that immune cells could get inside and do their jobs, the researchers reported Wednesday in the journal Science Translational Medicine.

Tumors shrank more in the high-oxygen group, especially when the researchers combined the oxygen with injections of extra tumor-fighting T cells, what's called immunotherapy. Extra oxygen had no effect in mice genetically engineered to lack those . Immunotherapy is a hot field in , as scientists try to figure out how to spur the body's own ability to fight tumors.

The study is exciting, said immunologist Susanna Greer of the American Cancer Society, who wasn't involved with the research and cautioned that it must be tested in people.

"If this works, there is the potential that what they're doing could very easily synergize with other cancer immunotherapies that we know work," she said.

"The beauty is that oxygen per se is so well-tolerated," added Dr. Holger Eltzschig, an anesthesiologist at the University of Colorado in Denver who studies low-oxygen effects and also wasn't involved in Wednesday's study.

He said the data was compelling enough to start testing the approach by adding supplemental to certain cancer therapies.

More information: Immunological mechanisms of the antitumor effects of supplemental oxygenation, Science Translational Medicine, stm.sciencemag.org/lookup/doi/ … scitranslmed.aaa1260

Journal information: Science Translational Medicine

© 2015 The Associated Press. All rights reserved.

Citation: Mouse study finds extra oxygen may spur tumor-fighting cells (2015, March 4) retrieved 19 March 2024 from https://medicalxpress.com/news/2015-03-mouse-extra-oxygen-spur-tumor-fighting.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Explore further

Protein may be key to cancer's deadly resurgences

136 shares

Feedback to editors