ASU Research E-Magazine: Growing Vitamin Factories

Plants as living vitamin factories. That is one idea behind current research being conducted by ASU plant biologists. Ilga Winicov and Kenneth Hoober are attempting to create a new source of human vitamin D binding protein that could be used in treatment for various diseases, including cancer.

To do so, they must splice genetic information for human vitamin D binding protein into an alfalfa plant. Once the genetic information is in the plant, the scientists hope to isolate a pure form of the protein that can be used for medical treatment.

For humans, vitamin D binding protein is important for general nutrition and bone strengthening. It also plays an important role in the activation of the body’s natural defenses against disease.

“Using the tools of biotechnology, we can take the information encoded in human DNA and put it into plants,” says Winicov, a plant molecular biologist. “With a few modifications, we can have the plant make a human protein.”

The everyday uses of the protein would have to be decided by physicians, Winicov adds. However, the protein has potential use as an agent to help invigorate and activate the body’s fight against tumors or infectious agents in ailing patients.

“Human vitamin D binding protein helps in the process of activating macrophages, immune system cells that attack cancer and virus-infected cells," Winicov explains. “We all have this protein in our blood, but the active amounts can sometimes be very low.”

However, there are real concerns about using the protein for medical treatment. First, because it is obtained from human blood, the protein can be contaminated with infectious agents. More specifically, blood-based treatments can carry viruses and other diseases. The Food and Drug Administration does not routinely permit them as acceptable treatments.

This is where bioengineering and the plant biologists enter the story. By splicing the information from human DNA necessary to build vitamin D binding protein into an alfalfa plant, the possibility for contamination with infectious elements is eliminated.

The alfalfa is grown in a greenhouse hydroponically–in a liquid solution rather than in soil. Winicov says the alfalfa plant could make and secrete the vitamin D binding protein and other needed molecules from its roots. These substances would be harvested and purified for human use.—Gary Campbell