Scientists in Canada say they've created a cancer tumor in a lab that can be unrolled like toilet paper to allow them to better understand how cancer cells grow and behave.
Researchers at the University of Toronto say the rolled-up strip of cancer cells mimics the three-dimensional environment that a tumor in the human body exhibits; however, it can be pulled apart in just seconds for analysis in the search for new therapies and drugs.
Previously, attempting to study cancerous cells grown in a laboratory petri dish was difficult, as the flat two-dimensional environment was different from the way a tumor grows within the body.
In a growing tumor, cells in its center experience reduced access to nutrients and oxygen compared with cells near its outer surface closer to surrounding blood vessels, a difference that has significant impacts on cell behavior, the researchers note in their study published in Nature Materials.
There have been efforts to mimic this in the lab by injecting cancer cells into porous, spongy materials, but to study what was happening inside required a laborious process of peeling off layers of the structure one by one.
UT professor of chemical engineering Alison McGuigan says she was inspired to think of a different approach after talking with Radhakrishnan Mahadevan, another engineering professor.
"He wanted to do this analysis where you had to collect the cells in less than 10 seconds," she says. "That was the engineering problem: how do you separate the cells in a very rapid way?"
While gathering likely lab materials such as filter paper, scissors and petri dishes, and pondering how they might be quickly assembled and disassembled, McGuigan absent-mindedly began wrapping a strip of the filter paper around one of her fingers.
"I looked down at it, and realized that's how you do it," she says.
To create a prototype, the researchers impregnated a strip of porous paper-like substance with collagen — the gel-like tissue present in the human body — and with cancerous cells.
The long sheet was wound around an inner core of metal to create an engineered tumor that was cultured in a nutrient-rich solution.
When the lab tumor was unwound, the researchers were able to quickly determine a difference between the innermost and the outer layers.
"As the oxygen level goes down, the number of dead cells in the layer increases, so the cells are responding to that oxygen gradient," says chemical engineering doctoral student Darren Rodenhizer.
While the same thing could be observed in 3D pieces of porous material stacked like building blocks, it would be a much longer and more difficult process, he says.
"If you had a stack, you could take it apart, but then you'd have all these separate, discontinuous pieces to keep track of," he explains. "We have one layer."
The process could lead to personalized treatments for cancer, McGuigan suggests. She goes on to explain that the concept would involve using a patient's cells and creating copies of their tumor, and that the copies would then be analyzed and subsequently treated while using the unrolling process, which would give the best information as to what would work best for each individual patient.
