A Researcher's Unexpected Journey

April 2011
Summary illustration - A Researcher's Unexpected Journey

Summary

A Mayo scientist went from examining bioluminescence in fungi to making strides in cancer research. With boundless enthusiasm and efficiency, Wilma Lingle, Ph.D., also supports the research community by running two genomic infrastructure facilities.

Wilma Lingle, Ph.D.

Wilma Lingle, Ph.D., oversees biospecimen collection and storage for Mayo Clinic.

Wilma Lingle, Ph.D., is one of those researchers whose curiosity has ventured from plants to people. Today, she works high atop Mayo Clinic's Stabile Building, where she oversees not only her own laboratory but also two facilities that support other investigators. She reflects many Mayo scientists who have no uncertainty as to why they come to work every day.

Lives are in the balance. She notes: "As a scientist reviewing the studies you're saying, 'This is a very cool experiment. This is a great idea.' But the patient advocates, who are well-versed in science and very articulate, are asking, 'What does it do for me?' "

From fungus to human biology

For the soft-spoken dynamic Georgia native who began her career as a botanist, that sense of purpose continues to carry her work great distances. Dr. Lingle's lab has made strides understanding how cells divide errantly in certain types of breast cancer, pinpointing new targets for treatment. Her expertise in cellular biology, as well as in cellular imaging techniques, has engaged her in a wide range of cancer research collaborations across Mayo.

But her career took on another dimension several years ago, when she became a leader of two core laboratories that facilitate research by providing scientists with biospecimens such as tumors that come straight from the operating rooms. Those labs have not only boomed with her guidance, but they've become models of how to process and prepare samples for research.

It was a scientific twist of fate that led Dr. Lingle to cancer research in the first place. She began her graduate career at the University of Georgia, studying cellular mechanisms related to bioluminescence in fungi. A journey to Mayo in 1997 seemed like it would be only a temporary venture when her husband, biochemist Dennis O'Kane, Ph.D., was invited for a single-purposed stint, applying his expertise in bioluminescence to a genetic research study. As it turned out, both of them have been Mayo faculty ever since.

Dr. Lingle landed a postdoctoral position in the lab of biochemist Jeffrey Salisbury, Ph.D. Also a botanist by training, Dr. Salisbury had turned his focus toward human cells and was studying the structures known as centrosomes, involved in chromosome replication when cells divide. He was the first to describe the protein centrin, at the hub of centrosomes and a characteristic of all eukaryotic organisms. Dr. Lingle's background fit well in the new lab. "I'd studied the analogous structures in fungi, though I'd never imagined my work would have anything to do with biomedical research," she says.

... to cancer cells

Fluorescence microscopy images of breast tissue

In these fluorescence microscopy images, the centrosomes are red and the nuclei are blue. Image A shows the normal breast with centrosomes of more uniform size. In image B the precancerous breast tissue has slightly larger than normal centrosomes.

Normal cells in culture

Normal cells in culture. One cell in mitosis that has a pair of centrosomes — one on each side of the metaphase plate of DNA — that form the mitotic spindle poles. Two other cells are in interphase. The cell on the lower left has a single centrosome composed of two small centrioles that appear as adjacent red dots. The cell on the lower right is preparing to enter mitosis. Its pair of centrioles has separated and will ultimately form the mitotic spindle poles seen in the mitotic cell.

With heady energy and great curiosity about the role of centrosomes in human disease, Dr. Salisbury and Dr. Lingle decided to investigate centrosomes in breast cancer cells. But the team hit a rough patch right out of the gate. "Our first experiments were dismal," Dr. Lingle recalls. The antibodies that had worked perfectly in cultured cells wouldn't attach to the antigens in chemically preserved breast tumor tissues. Dr. Lingle set out to try to acquire fresh, frozen tumor tissues. "I knew they existed here, but I didn't know how to access them," she says.

Ultimately, another researcher provided tissue samples to test out, and Dr. Lingle got to work, learning to cut and prepare frozen sections of tumor. The experimental results were stupendous. The antibodies attached just as they were supposed to, and the team discovered the presence of abnormally amplified centrosomes in cancer cells, publishing a 1998 paper in Proceedings of the National Academy of Science. "People had predicted before that there would be an aberrant number of centrosomes in abnormally dividing cells, but nobody had shown it until then," she says.

The findings set her on a cancer research tack, and she received a five-year Department of Defense Career Development Grant to establish her own lab. Since then, she's gone on to describe molecular mechanisms that derail centrosomes. Her group found that when an enzyme called aurora kinase adds a phosphate group to the centrin protein, damage to the centrosome ensues. "That can promote duplication of centrosomes out of sync with the duplication of chromosomes, an instability that can be a precursor to cancer," she explains. The results, published in PLoS One, may help drug companies target overactive aurora kinase to prevent centrosome damage.

Her work branched, meanwhile, to tackle other cancer research with a range of approaches. "Wilma's become extremely knowledgeable about many cancers, and what she doesn't know, she learns fast," says molecular biologist Thomas Spelsberg, Ph.D. He involved her in a research collaboration that's now challenging a paradigm in cancer care.

Dr. Spelsberg has been studying estrogen receptors in breast cancer cells. The presence of the alpha receptor molecule was long thought to be the sole determinant of whether patients should receive the drug tamoxifen, but their collaboration is showing that the beta receptor also facilitates the drug. "That means a lot of patients are not being treated who should be," he says. In another project, Dr. Lingle has brought her microscopy expertise to bear, working with experimental pathologist Monica Reinholz, Ph.D., and looking at whether tumor cells in circulating blood cause metastases.

Supporting science: State-of-the-art genomic infrastructure

Lab personnel scanning cryovial labels

Quality control: Biobank blood specimen bar codes in the BAP core facility are scanned to double-check accuracy of the labels on DNA cryovials.

But it was the initial difficulties she'd experienced with chemically preserved cancer tissues that instilled an appreciation for the frozen biological resources available at Mayo. When the opportunity arose several years ago to direct two core laboratories that process and analyze human tissues and biospecimens for research, she recognized the significance of the role. Today, she co-directs the Biospecimens Accessioning and Processing (BAP) Shared Resource core facility, along with molecular geneticist Edward Highsmith, Ph.D.

What 10 years ago was a small service outside the operating room has moved to its own floor and become a bustling resource that's also a marvel of efficiency. Today, with consent from patients, and with special approval from institutional review boards that affirm the ethics of research plans, the tumor and tissue samples removed in the operating room are first viewed by pathologists who inspect them and determine their status for patient treatment. Then, the remainder is frozen on-site and whisked by pneumatic tube to the BAP facility, where it's labeled with a bar code to remove patient identification, and prepared for research. Last year BAP processed nearly 1 million samples, including tumors, blood, serum and sputum, providing material for more than 700 research studies at all three Mayo campuses and around the world. It's also preparing and storing samples for the Mayo Clinic Biobank, a major resource for genomic-based disease research.

BAP has become known for its rigid processing protocol, ensuring consistency among cells. Dr. Highsmith, who oversees the lab's quality control, relates that an international genome center that received BAP samples counted them among the highest quality from anywhere in the world, and requested the preparation protocol. Dr. Lingle has also had an eye on making sure BAP's good work lasts.

Recently she was responsible for the acquisition of a $1.5 million state-of-the-art minus 80 degree Fahrenheit freezer, capable of storing 600,000 samples processed by BAP in tiny vials for future studies. Funded by philanthropic support, the freezer is equipped with an interior robotic arm that retrieves vials and even reorganizes the shelves so that the door never swings open compromising the temperature for other samples in storage.

Adjacent to the BAP lab is Dr. Lingle's other charge, the Tissue and Cell Molecular Analysis (TACMA) Shared Resource core facility, which offers specialized techniques to stain and prepare cells for microscopy. Researchers who need a particular cell preparation can sit with Dr. Lingle and pathologists from the Division of Anatomic Pathology to discuss the range of histology techniques available and establish research plans. Because equipment is expensive, the lab's cell services aren't cheap; researchers fund these services with grant dollars.

Through TACMA, researchers can prepare digital images of the microscopy studies, to send to collaborators across campus or even internationally. One significant advance for researchers is the ability of the lab to create tissue microarrays, a process that requires pricey tools. But each microarray, a microscope slide with tiny dots of tissue — each 0.6 millimeter in diameter — in a grid shape, enables researchers to compare hundreds of tissue samples side by side with efficiency and at reduced expense. "This kind of resource is important at a time when research funding is so tight," Dr. Lingle says.

Together the core facilities have made possible research that was almost unthinkable a decade ago. "It used to be that you'd have to search around the world for who had what kind of tissue samples," says Dr. Spelsberg. "It could take six months to a year to get the cells. Or you just wouldn't bother trying. Now we can do important projects we never would have been able to before."

For Dr. Lingle, the research in all its forms continually returns to the question of how it will serve patients. "That's where it is," she says. "That's what we're doing ... pushing the science forward, toward treatment."