Chicago Health | Homepage
Researchers discover how immune cells resist radiation treatment

Researchers discover how immune cells resist radiation treatment

Source: Icahn School of Medicine at Mount Sinai

whatdoctorsknow.com

Researchers at The Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai have discovered a key mechanism by which radiation treatment (radiotherapy) fails to completely destroy tumors. And, in the journal Nature Immunology, they offer a novel solution to promote successful radiotherapy for the millions of cancer patients who are treated with it.

The team found that when radiotherapy damages skin harboring tumors, special skin immune cells called Langerhans cells are activated. These Langerhans cells can uniquely repair the damage in their own DNA caused by radiotherapy, allowing them to become resistant to radiotherapy and to even trigger an immune response causing skin tumors such as melanoma, to resist further treatment

Investigators mimicked the effect of immunotherapy drugs called “immune checkpoint inhibitors” to boost the immune system to attack tumors. This in turn blocked the ability of Langerhans cells to repair their own DNA after radiotherapy causing them to die, preventing an immune response that protects skin tumors.

“Our study suggests that this combination approach — combining radiotherapy with drugs that rev up a healthy immune response — will help make radiation therapy much more effective,” says the study’s lead author, immunologist Jeremy Price, Ph.D.

While this study was conducted using mouse models of melanoma and focused on the skin where these Langerhans cells are located, the researchers believe the same process happens in organs throughout the body. There, cousins of Langerhans cells called dendritic cells are also activated by radiotherapy and the investigators stressed that it is critical we understand how they respond to treatment as well.

Ionizing radiation is a powerful therapeutic tool that causes toxic breaks in cellular DNA. The formation of these breaks triggers a response in Langerhans cells (which are usually dormant) to stop further damage and to repair the breaks.

The researchers discovered that when the skin is damaged by ionizing radiation, Langerhans cells travel to nearby lymph nodes to communicate with other immune cells and help program a population of “regulatory” T cells that dampen the immune system. These regulatory T cells then travel back to the damaged tumor, and shield it from attack by the immune system.

“We found melanoma grew much more quickly on mice pretreated with radiation, compared to untreated mice, because of the presence of regulatory T cells activated by Langerhans cells,” Price says. “These Langerhans cells were resistant to radiation.”

The researchers also discovered that Langerhans cells are able to resist lethal doses of radiation because they express very high levels of an important protein involved in the stress response that orchestrates DNA repair after radiotherapy.

“Any treatment that prevents tumor infiltrating regulatory T cells from being produced, such as immunotherapy, will improve the outcome from radiation treatment — and that will save lives,” Price added.

(WhatDoctorsKnow is a magazine devoted to up–to–the minute information on health issues from physicians, major hospitals and clinics, universities and health care agencies across the U.S. Online at www.whatdoctorsknow.com.)

(c) 2016 WHATDOCTORSKNOW.COM. DISTRIBUTED BY TRIBUNE CONTENT AGENCY, LLC.

Similar Articles

Beyond Chemo

Beyond Chemo

Immunotherapy treatments rev up immune system to fight cancer By Katie Scarlett Brandt Six years ago Henry Kawell, then 72,

Count ingredients, not calories

Count ingredients, not calories

By Sharon Palmer, R.D.N. Shift your focus from the calories label to the ingredients label, and

Pneumonia a leading cause of hospitalization for children

Pneumonia a leading cause of hospitalization for children

What Doctors Know Source: U.S. Centers for Disease Control and Prevention Pneumonia puts thousands of young children

Getting Over It: Why You Should Get a Colonoscopy

Getting Over It: Why You Should Get a Colonoscopy

Facing the discomfort of a colonoscopy is a sure way to avoid the greater discomfort and

Cartilage repair, restoration becoming more common

Cartilage repair, restoration becoming more common

DEAR MAYO CLINIC: I recently heard about cartilage being used in knee joints. Last summer

Articles By Category

Family Health

In The Know

CH Lifestyle

September 2016
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
August 28, 2016 August 29, 2016 August 30, 2016 August 31, 2016 September 1, 2016 September 2, 2016 September 3, 2016
September 4, 2016 September 5, 2016 September 6, 2016 September 7, 2016 September 8, 2016 September 9, 2016 September 10, 2016
September 11, 2016 September 12, 2016 September 13, 2016 September 14, 2016 September 15, 2016 September 16, 2016 September 17, 2016
September 18, 2016 September 19, 2016 September 20, 2016 September 21, 2016 September 22, 2016 September 23, 2016 September 24, 2016
September 25, 2016 September 26, 2016 September 27, 2016 September 28, 2016 September 29, 2016 September 30, 2016 October 1, 2016

Categories

Recent Comments

Swing for the fences in the fight to Sideline Pancreatic Cancer

Swing for the fences in the fight to Sideline Pancreatic Cancer

Enjoy a great night of baseball at Peoples Natural

VIEW ARTICLE
Cost to give birth 1943 - Page 3 - Defending The Truth Political Forum

Cost to give birth 1943 - Page 3 - Defending The Truth Political Forum

A Hazy Shade of Healthcare: What does tort reform

VIEW ARTICLE

Archives