How does this work?
It is called suicide gene therapy. And this is the concept: find a gene coding for an enzyme that human cells don't have. Insert that gene only into cancer cells--not normal cells. This enzyme works by taking a harmless "pro-drug" and converting it into a toxic compound. Early attempts at this therapy used the enzyme thymidine kinase from the herpes simplex virus. This enzyme converts the drug ganciclovir into a compound that stops DNA synthesis. If a cancer cell can't make new DNA, it will eventually die.
The current paper uses the thymidine kinase gene from the tomato plant. The gene is delivered to GBM cells by neural stem cells. The tomato thymidine kinase acts on the drug AZT and converts it into compounds that interfere with DNA synthesis.
AZT might sound familiar. It is a retroviral agent used to treat patients with HIV. Jerome Horwitz first created the compound in 1964 while at the Karmanos Cancer Center in Detroit. The drug works by preventing the RNA of the HIV virus changing itself into DNA.
While tomato gene therapy may or may not make it to clinical trial stage, it is important for you to know that throughout the world, creative and ingenious new treatments for GBM are being developed all the time.