Chris Mason, professor of regenerative medicine at University College London, said: "This is a clever study, which signals the beginning of the next wave of therapies.
"It shows you can attack solid tumours by putting mini pharmacies inside the patient which deliver the toxic payload direct to the tumour.
"Cells can do so much. This is the way the future is going to be."
Nell Barrie, senior science information manager for Cancer Research UK, said it was an "ingenious approach".
"We urgently need better treatments for brain tumours and this could help direct treatment to exactly where it's needed.
"But so far the technique has only been tested in mice and on cancer cells in the lab, so much more work will need to be done before we'll know if it could help patients with brain tumours."
She said this type of research could help boost survival rates and bring much-needed progress for brain cancers.
Dr Shah now plans to test the technique using a number of different therapies on mice with glioblastoma, the most common brain tumour in human adults.
He hopes the therapies could be used in clinical trials within the next five years.