A Bed Of Mouse Cells Helps Human Cells Thrive In The Lab

By Richard Harris

Published January 7, 2015 at 3:37 AM EST

Dr. Richard Schlegel and postdoctoral fellow Nancy Palechor-Ceron use a microscope to look at human epithelial cells growing on mouse fibroblasts at Georgetown University Medical Center.

A drug that is used worldwide to treat malaria is now being tested as a treatment for cervical cancer. This surprising idea is the result of a new laboratory technique that could have far-reaching uses.

Our story starts with Dr. Richard Schlegel at Georgetown University Medical Center. He's best known for inventing the Gardasil vaccine to protect women from cervical cancer.

Schlegel wished he could take cancer cells from women who came to the hospital for treatment and grow them in the lab to learn more about this disease.

"People have tried growing cells in culture before, but they've been very crude experiments, essentially," he says. Most of these freshly collected cells die off quickly in the lab.

But Schlegel had an idea for a radically new method to grow all sorts of human cells. The secret to keeping them alive indefinitely is to grow them on a bed of cells that come from mice. These mouse cells have been blasted with radiation to prevent them from multiplying, and the culture is then treated with a compound (called a ROCK inhibitor) that regulates cell growth.

You can see these spindly cells coating the bottom of a flask when you look at them through a microscope.

Schlegel says he doesn't know exactly what these mouse cells provide the human cells to keep them alive and growing. "There are probably several growth factors that they secrete that are important ... and we have experiments ongoing to identify what those factors are," he says.

If he can figure that out, eventually he can dispense with the mouse cells. But for now, the layer of mouse cells is the key.

So far, he has grown more than 30 types of cancer cells — as well as many normal human cells that he studies for comparison. All told, Schlegel says, he has grown up cells from 700 different samples of human tissue.

Recently he took some cervical cancer cells and started dosing them with drugs to see what would kill them. He tried all sorts of other available medicines, not not just drugs used to treat cancer.

And much to his surprise, he found that a drug commonly used to treat malaria will also kill cervical cancer cells. It's a form of artemisinin.

Schlegel is now collaborating with researchers at the Johns Hopkins University School of Medicine to test this drug in women who have precancerous growths on their cervix.

Dr. Connie Trimble is running the drug trial at Johns Hopkins. She will offer this drug to women who are likely to require cervical surgery in the coming months. She hopes that, instead, the drug will kill off the cervical cancer cells in women, as it did in the lab.

"If it works, this is a game-changer," Trimble says, "because it puts control of treatment in the hands of the woman. In low-resource settings, or settings where women don't have access to health care, they can do it themselves."

Doctors already know this anti-malarial drug is safe, so it could be a front-line treatment in parts of the world where surgery simply isn't available. It would require an easy diagnostic test women can use at home; Trimble says that's also in the works.

And cervical cancer is just the start. Dr. David Rimm at the Yale University School of Medicine learned about the Georgetown cell-growing method when it was first published two years ago. And now he's using it to generate cell lines.

"It's pretty cool," he says. "We have over 100 [types of cells growing] in our facility."

Rimm says this is a huge step for research labs. It used to be that he could only study a few perpetually growing cell lines, and those were biologically pretty messed up.

"We can now have 40 or 50 cell lines from 40 or 50 different tumors from a population, and they all grow," he says. "And we can now do cell-line type studies, but on populations of cell lines as opposed to two or three."

That gives him the same advantages scientists get when they test new drugs on dozens of people instead of just a few.

Schlegel says at least 30 labs around the world are now using this technique, which is called "conditional reprogramming" of cells. And at the moment, everyone is hopeful that it will be the next big thing for studying diseases in the lab. But it's still just a bit early to make that bold of a claim.