Glioblastomas are highly aggressive brain tumors that are notoriously difficult to treat, with the cancer cells often slipping away from the main growth and into the brain, leading to high rates of recurrence down the track. In search of more effective therapies, scientists are investigating how the cell-destroying abilities of certain viruses can be leveraged to better remove the threat. A team at Yale University is now reporting an exciting breakthrough in this area, with components of the Ebola virus put to use in a promising new therapy that proved capable of killing glioblastomas in mice.
Standard treatments for patients with glioblastomas involve surgery to first remove the tumors, then chemotherapy and radiation therapy to destroy any remaining cancer cells. The trouble is, these evasive cells often escape into the brain tissue, where they hide and in time often give rise to new tumors that prove fatal.
It sounds counter-intuitive, but viruses that would normally cause dangerous infections to humans have the potential to help hunt down these tiny traces of leftover cells. For more than half a century, scientists have been working to engineer different viruses with the ability to target and kill cancer cells, with one 2017 study showing how the Zika virus could be harnessed to attack gliablastomas one recent example.
The logic for this approach is couched in how cancer cells respond to foreign threats. When pathogens or other invaders launch an attack on the body, normal healthy cells trigger an immune response in defense, whereas the majority of cancer cells are incapable of this. Attacking cancer cells with viruses could therefore exploit this vulnerability, while leaving healthy cells largely unharmed.
And the Ebola virus presents a particularly promising candidate. Led by professor of neurosurgery Anthony N. Van den Pol, the Yale team has been studying the makeup of the virus in hopes of putting some of its powerful tools to good use. In doing so, they uncovered a single gene with two desirable attributes, in that it both helps the virus evade the immune response of the body (so it can effectively do its job), and it also plays a role in the virus' lethality (so it can attack the cancer cells).
The scientists worked this gene into what is known as a chimeric virus, which are made up of gene combinations taken from multiple viruses. This chimeric virus was injected into the brains of mice with glioblastoma, with the team finding that the gene taken from the Ebola virus enabled it to selectively target and destroy the brain tumors.
Van den Pol says that with further work, this type of virus could one day be used in combination with surgery as a way of lowering the risk of recurrence.
“The irony is that one of the world’s deadliest viruses may be useful in treating one of the deadliest of brain cancers,” he says.
The research was published in the Journal of Virology.
Source: Yale University
