UFGI researcher immortalizes NF1 neurofibroma Schwann cells

Although tumors are typically best-known for their capacity to grow quickly, not all of them are so robust. This limited life span creates challenges for scientists attempting to research them.

A University of Florida research team recently discovered a method for boosting the life span of one type of tumor. Peggy Wallace, PhD, a professor in the department of molecular genetics and microbiology, introduced two genes into cells from tumors that forms along nerves, and significantly boosted their longevity in culture. Their results were published in Laboratory Investigation.

“This is a new resource for basic science and probably translational work toward testing therapies, developing therapies,” Wallace said. “We’ve been happy with how successful it was.”

Wallace studies neurofibromas, which are Schwann cell tumors. Schwann cells occur naturally. They wrap themselves around nerves, and produce myelin– a protein that insulates electrical signals.

When a nerve is cut, Schwann cells divide, and form a bridge across the injury to provide a scaffold for the nerve to rebuild upon. Neurofibromas develop when Schwann cells don’t stop dividing, collect and form a lump.

“[They’re like] a wound that doesn’t stop healing,” Wallace said.

Although the tumors are often benign, the visible lumps sometimes make sufferers feel insecure about their appearance. Those on larger nerves can become painful, and some eventually do become malignant.

Historically, when scientists attempted to culture these tumor cells in the lab, they could only generate six-to-eight passages. Wallace said this does not allow for lengthy, meaningful study of different samples of tumor cells. They also contained traces of other cells, such as fibroblasts.

“They’re not ideal for a lot of the biology experiments that people would want to do to test new drugs,” Wallace said.

However, Wallace and her research team recently devised a method for inducing neurofibroma Schwann cells to grow more robustly in culture. They added two genes via viruses. These genes already exist in Schwann cells, but are not active enough. One makes an enzyme that helps cells live longer by keeping chromosome ends healthy, and the other is a gene whose protein product propels cell division.

Wallace said the culture cells now typically last at least 50 passages, and one has been tested to 80 with no signs of slowing– indicating the cells are truly immortal.

Not only do the cells last longer, they are better samples.

“You can get a lot more cells, and they are pure tumor cells, and they don’t have background of other kinds of cells in them,” Wallace said.

Not all neurofibromas are identical. Having access to purer samples will enable researchers to more accurately analyze different tumors from different people, with the hope of enhancing understanding their individual pathologies.

“Now we have enough biology to start to get some good ideas about therapies,” Wallace said. “We really need to understand more about the rates of different tumors in people, and try some different kinds of biology approaches that are out there now.”