Scientists discover ‘Achilles heel’ of brain tumor cells: Brain tumors, especially glioblastoma, are among most aggressive cancers as they are prone to regeneration.
Like the famous many-headed monster in Greek myths, cancer is the Hydra of the medical world. Finding a way to control its growth leads to the cancer adapting itself to deal with any eventualitya. Brain tumors are especially difficult to treat. Even when subjected to radiation, chemotherapy or surgery, they always find a way to return.
Research On Brain Tumor Cells
According to American Cancer Society, around 22,850 malignant tumors of the brain or spinal cord (12,900 in men and 9,950 in women) will be diagnosed in 2015. These do not include estimations for benign tumors. Out of brain tumors the most common, aggressive and lethal form is glioblastoma. It tends to grow very quickly in brain cells but very rarely spreads to other organs of the body.
Around 18,000 people in the United States are diagnosed with GBM every year while it causes 13,000 cancer related deaths in the US annually. Removal of the tumor by surgery followed by radiotherapy and chemotherapy is considered the best bet. Unfortunately, as GBM is a recurrent disease, it either returns or progresses even after treatment.
Scientists have discovered that the ability of certain brain tumor cells to regenerate is traced to cancer stem cells, which are resistant to treatment. These resistant cells also encourage the growth of new tumor cells.
Scientists at Washington University in St. Louis may have discovered what they dub as the “Achilles heel” of glioblastoma tumor cells. A key player involved in maintaining the cancer stem cells astonishing regeneration abilities has been identified. Furthermore, if the process is disrupted then the spread of cancer is disrupted as well.
Senior Author Albert Kim, MD, PhD, assistant professor of neurological surgery said, “This discovery will help us attack the root of some of the deadliest brain tumors. Blocking the tumor cells’ ability to survive and replenish themselves will likely lead to a successful brain cancer treatment.”
Kim and his colleagues identified a protein SOX2 which is active in healthy stem cells in other parts of the body as well as in brain tumor stem cells. They found that the brain tumor cell’s ability to make SOX2 was regulated by another protein CDC20.
By boosting levels of CDC20, the increase in amount of SOX2 helped elevate the tumor’s ability to grow when transplanted in mice. On the other hand when CDC20 was eliminated, the tumor cells could not make SOX2 and hence it reduced the stem cell’s ability to make new tumors.
“The tumor stem cells are actually the kingpins of cancer. They drive and direct much of the harm done by tumors,” explained Kim in a press release. “But if CDC20 was removed, the rate of growth of some tumors dropped by 95% compared to those with normal levels of CDC20.”
Upon examining human brain tumor samples, scientists found that Glioblastoma patients with the highest CDC20 levels had shortest survival rates after being diagnosed.
The research team is also looking for methods to block the production of CDC20 in brain tumors. RNA interference, which involves blocking the production of specific proteins, is being explored as a possible approach. It is already in use in clinical trials for the treatment of various illnesses, including cancer.
The research findings were published online in the journal Cell Reports on June 11. The National Institute of Health (NIH), the American Cancer Society, Voices Against Brain Cancer, the Concern Foundation, the Elsa U. Pardee Foundation, and the Duesenberg Research Fund, all supported the research.
Neurosurgeon Albert Kim, MD, PhD, shown planning for surgery, leads a team that has identified a new vulnerability in brain tumor stem cells. Such cells are notorious for their ability to resist treatment and regrow tumors.