Immunotherapy is a promising type of treatment that activates the body’s own immune system to destroy tumor cells. So far, this kind of therapy has not been successful enough for children with brain tumors. That’s why researchers are exploring new strategies to make immunotherapy available and effective for these children.
Viruses that attack tumor cells
One of the researchers at the Máxima Center studying immunotherapy for childhood brain tumors is Konstantinos Vazaios, a PhD student in the Hulleman group. He investigated so-called oncolytic viruses, which can infect and destroy cancer cells. At the same time, they activate the immune system, prompting the body to help attack the tumor. With his research, Vazaios has laid the groundwork for using these viruses as a form of immunotherapy for children with brain tumors.
Vazaios examined several types of oncolytic viruses, looking at both naturally occurring variants and genetically modified ones that were adapted for safety or to target tumor cells more effectively. He tested them in the lab using cells from children treated at different hospitals, including the Máxima Center, for different types of brain tumors. Each virus turned out to have a preference for attacking tumor cells with specific characteristics. ‘Those preferences give us clues for which tumors these viruses might be a suitable therapy,’ Vazaios explains.
Smart combinations
In his research, Vazaios not only looked at how the viruses affect cancer cells, but also how they work in combination with other forms of immunotherapy. He worked with colleagues at UMC Utrecht and in the Nierkens group to test oncolytic viruses together with two types of modified immune cells used in immunotherapy: TEG cells and CAR T-cells.
When combined with oncolytic viruses, these immune cells became stronger and more effective in clearing brain tumor cells. CAR T cells, in particular, showed promising results in combination with the viruses. Vazaios: ‘This combination approach could eventually lead to treatments that are not only more effective but also less harmful to healthy cells.’
Contributing to better treatments
Vazaios’s research is still in an early stage: he studied how the viruses work in tumor cells. There are already some early clinical studies using oncolytic viruses in children with brain tumors, but more research is needed to confirm the results in larger groups of patients.
Vazaios: ‘I hope my research can lay the foundation for further studies to explore the potential of oncolytic viruses for children with brain tumors. Brain tumors are difficult to treat, and it would be wonderful if, in a few years, these findings could help lead to a new type of immunotherapy for children with aggressive brain tumors.’
Now that he has successfully defended his PhD, Konstantinos plans to continue his research abroad, ideally in Sweden, focusing on translational immuno-oncology, cell and gene therapy. An international clinical trial led by the Máxima Center will start next year to test the benefit of the oncolytic virus approach in children with a brain tumor.
The PhD research of Konstantinos Vazaios was supported by Inspire2Live, Choir4Hope, KiKa (Children Cancer Free Foundation), Team Westland and the Van der Velden family.