Low-dose X-rays can destroy brain tumor cells!
Using very low-dose X-rays activates compounds that kill cancer with free radicals, halts brain tumor growth and doubles survival time, according to a new study. Most importantly, healthy cells remained unaffected.
Common X-ray cancer treatments
We know that X-rays penetrate deep into the tissues of the body, which is why they are used to deliver cancer radiotherapy. While radiotherapy uses X-rays to damage the DNA of tumor cells and kill them, photodynamic therapy uses a different method to achieve the same result.
The photons in the laser beam are used to excite light-reactive molecules called “photosensitizers” embedded in tumors, causing the production of cancer-killing free radicals.
Both treatment methods have disadvantages. Radiotherapy can damage healthy cells near the tumor and lead to side effects such as nausea and hair loss. Photodynamic therapy cannot reach deep tumors.
In a New study Led by Nanyang Technological University, Singapore, the researchers used a combination of radio and photodynamic therapies, known as radiodynamic therapy, to target and destroy brain tumor cells.
This treatment relies on a new compound called MRAP, which consists of biochemical substances and iodine. Compounds commonly used in radiodynamic therapy contain heavy metals that can cause cell damage. But MRAPs do not contain heavy metals.
They are injected directly into the tumor and activated by X-rays at a dose much lower than that used in existing radiotherapy. Importantly, they are activated only in the presence of CatB enzyme. This enzyme is regulated in cancer cells and plays a role in tumor growth and development.
When activated, MRAPs produce a bright “infrared afterglow” and cancer-killing free radicals.
Experiments on animal samples
The researchers tested this treatment on mouse models of brain cancer, specifically glioblastoma. Glioblastoma is a fast-growing tumor that has one of the lowest survival rates among cancers in humans.
MRAP-injected tumors were treated with an equivalent X-ray dose more than six times lower than the usual dose.
After treatment, the tumors stopped growing and treated mice survived twice as long as untreated mice. In addition, the researchers found that MRAPs do not produce free radicals in healthy cells, so they have no side effects. There were also no signs of tissue damage or weight loss. MRAP compounds were finally excreted through the urine and feces of the animals.
“We used extremely low doses of X-rays and cancer-killing MRAPs,” said lead author and co-author of the study Professor Pu Kanyi. The anti-cancer compounds were only active in brain tumors and not healthy cells. Therefore, we expect our treatment method to be safer and have fewer side effects than existing methods.”
The researchers will continue to evaluate the safety and efficacy of MRAPs in larger clinical models before beginning human trials. They are also working on improving MRAP's ability to target cancer cells and adding immune-boosting capabilities to help the body fight cancer recurrence.
