Study shows Zika virus potential for treating a childhood cancer

NEW YORK: In a significant breakthrough, a team of US researchers harnessed Zika virus to shrink or eliminate neuroblastoma tumours in mice studies, an advance that suggests the deadly virus could someday serve as an effective cancer therapy.

Neuroblastoma is a rare childhood cancer that typically develops in the sympathetic nervous system or the adrenal glands.

More than half of patients with high-risk neuroblastoma do not respond to chemotherapy or radiation, or they respond initially, but develop a recurrence. In recent years, it has been discovered that Zika virus, which is carried by mosquitoes, can potentially be used to kill cancer cells. Zika virus infections in pregnant women can cause serious birth defects as the virus targets CD24, a developmental protein.

Previous research has suggested that certain cancers that express the CD24 protein are also vulnerable to the Zika virus, opening the door for Zika virus to be used as a treatment.

To explore, researchers from the Nemours Children's Health System examined Zika's potential against neuroblastoma.

The researchers studied mice with neuroblastoma tumours that express high levels of CD24. They injected half of the mice with a saline solution, and the other half with Zika virus.

Tumour sizes were monitored three times a week thereafter. The study, published in Cancer Research Communications, showed that all mice injected with the Zika virus experienced a nearly total loss of tumour size. The highest dosage tested resulted in complete elimination of the tumour, which was confirmed by an independent Nemours Children's pathologist.

In four weeks of follow-up, there was no recurrence of the tumour. Furthermore, the mice did not develop any symptoms of Zika virus infection or any side effects.

"With further validation, Zika virus could be an extremely effective bridge therapy for patients with high-risk neuroblastoma," said Joseph Mazar, Research Scientist at Nemours Children's.

"We also see potential for Zika virus to be used to treat children and adults with other cancers that express high levels of CD24."

Further, to determine whether treatment with Zika virus is likely to help human patients survive longer, the researchers developed mouse models of human neuroblastoma tumours, treating them with either Zika virus or a saline solution.

Twenty-eight days after the treatment, all tumours that received the saline solution had grown by as much as 800 percent.

The tumour models that had received Zika had shrunk to approximately 12 per cent of the original mass, which was confirmed to represent scar tissue rather than the tumour cells.

After four additional weeks, no further tumour growth was detected, suggesting that patients treated with Zika virus would be more likely to survive.