In a study published in Cancer Research, researchers are optimistic that new strategies could become known for slowing the growth and recurrence of the most common primary brain cancer in adults, glioblastoma.
Toronto's St. Michael's Hospital and The Hospital for Sick Children (SickKids) led the new research which suggests the protein ID1 is crucial to tumor initiation and development and also impacts the response of the disease to chemotherapy. ID1 is a protein that keeps other genes from being activated or repressed by binding to their activators or inhibitors. With this research, scientists discovered that ID1 helps cancer stem cells in glioblastoma, making them less susceptible to treatment.
A scientist at St. Michael's Keenan Research Center for Biomedical Science and The Arthur and Sonia Labatt Brain Tumor Research Center at SickKids, Dr. Sunit Das, said that the field has postulated for years that cancer stem cells are a small population within the tumor, but critical since they mediate treatment resistance and cancer resistance. Das noted that they have now discovered proof of that speculation.
The investigators discovered that when they turned off the protein ID1 in lab models and human cells using CRISPR technology or a drug that is traditionally used to treat psychosis and Tourette's syndrome - pimozide - glioblastoma tumors slowed down. Also, the researchers discovered that turning off the protein altogether helped tumors become less resistant to chemotherapy.
An aggressive form of brain cancer is glioblastoma, representing 15 percent of all primary brain tumors, and is often difficult to treat. Generally, therapy involves the combination of several approaches to control the disease, but there is currently no cure. The diagnosis of the late Tragically Hip singer Gord Downie and U.S. Sen. John McCain have raised the profile of glioblastoma in recent years.
In lab models, the team discovered that inhibiting ID1 slows the progression of tumors in glioblastoma, breast adenocarcinoma, and melanoma. In human tissue, researchers found that the protein caused cells to be more resistant to chemotherapy treatment in glioblastoma. When the researchers turned off this protein with the use of the medication pimozide, it increased overall survival and caused glioblastoma tumors to recur less frequently, progress less, and grow more slowly.
Dr. Das explained that targeting the protein with medication may present a new and potentially promising strategy for patients with glioblastoma. Dr. Das explained further that the next steps for this study are to look at the development of new inhibiting medications for ID1 and commence a trial to ensure that the targeting is effective.
