When scientists test new cancer drugs, they typically first test a molecule in a petri dish (called in vitro testing). If it kills cancer cells there, it can then be injected into a mouse or another animal with the disease (in vivo testing). In vitro tests are fast, but they can’t show how a treatment will work in a living body. Animal studies, on the other hand, are slow. The mice typically have to be euthanized and dissected to see how the medicine effected their tumors, which makes it challenging to see how the tumor behaves over time.
A team of biomedical engineers recently proposed a new option. To mimic glioblastoma, a type of brain tumor with a very low survival rate, these researchers turned to 3D printing. They first printed blood vessels to supply nutrients to a tumor of cancerous human brain cells. Around the blood vessels and tumor, they printed a gel to hold the system in place. The blood vessels could then be used to supply the tumor with nutrients that it needs to grow. Unlike mice, this system can be studied without destroying it. By shining a laser through the gel, they can measure the amount of light that is scattered by the tumor. Because of this, the research team was able to measure the growth of the tumor over time. To test whether this system mimicked real glioblastomas, the scientists treated it with temozolomide. In patients, this drug typically shrinks the tumor temporarily before becoming unsuccessful and allowing the tumor to grow back. They found that in their 3D-printed system the tumor grew until temozolomide was added. The temozolomide then slowed the growth temporarily before the tumor started to grow again, indicating that this system can mimic a cancerous tumor in a brain.
In the future, this technology could be used to test which cancer drugs quickly and reproducibly. Instead of having many ‘successful’ in vitro-tested drugs proceed to animal trials, which are long and have a high failure rate, the drugs could be tested in a similar 3D printed system to quickly narrow down the most promising treatments to test in animals. Adding this 3D-printing step to the process might actually reduce the time it takes to approve new drugs.
Corresponding Author: Emily Kerr
Popular Press Article: A 3-D-printed brain could make it easier to find cancer treatments
Scientific Article: High-resolution tomographic analysis of in vitro 3D glioblastoma tumor model under long-term drug treatment
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