Dr. Gay Crooks: Exploring the Human Side of Stem Cell Biology

For many scientists who are clinicians and researchers, balancing the demands of both disciplines can often feel more limiting than it is liberating. But for Dr. Gay Crooks, a physician who specializes in bone marrow transplantation for children and young adults who have cancer, it is precisely the synergistic opportunities that each offers that continues to bring her the greatest professional rewards.

“What most people can articulate best about their job is its limitations. I don’t feel that my work has many limits,” said Crooks. “There can be disappointments on the clinical side, but when you do research, you always have questions that you can seek answers for. For me, the biggest joy of the work is being able to pursue those questions. Truthfully, it’s a great feeling of freedom.”

Crooks, who runs a research program in bone marrow transplantation at UCLA’s Departments of Pathology and Laboratory Medicine and Pediatrics, had always dreamed of exploring both the human and scientific sides of medicine since growing up as a young girl in Western Australia. She admits to being influenced at a young age by the popular American television drama “Dr. Kildare,” and as each week’s story unfolded, she was transfixed by both the medical questions raised and the emotional issues confronted.

Though research opportunities were often not as plentiful in Australia as in the US, Crooks quickly found her niche in pediatric oncology, a path that allowed her to spend equal time in the laboratory and treating patients in the clinic. Crooks earned her medical degree from the University of Western Australia in 1982, and then completed her pediatric residency at the Princess Margaret Hospital for Children in Perth.

“I’d always been drawn to pediatrics, because I love working with children and families,” Crooks said. “Medicine is one of the few scientific disciplines that combines the minutiae and exploratory aspect of biology with the human side. Pediatrics also allows you to go beyond just the day-to-day with a patient. You usually see them over the course of their lifetime, and you’re in it for the long haul.”

Crooks still longed for even greater research challenges, however, and fueled by frequent professional trips abroad, became attracted to the cutting-edge research she saw being done in the United States. In 1989, she accepted a fellowship in pediatric hematology/oncology at Children’s Hospital Los Angeles. Newly married she and her husband relocated to the United States, where they have resided for the past 20 years and raised two children.

In 2009, Crooks was invited by UCLA’s Jonsson Comprehensive Cancer Center and the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research to join the faculty at UCLA. She currently is a professor in both the Department of Pathology and Laboratory Medicine and the Department of Pediatrics, and in 2010 was named Co-Director of the Jonsson Cancer Center’s Cancer and Stem Cell Biology Program Area.

“UCLA is a fantastic environment for science and medicine,” said Crooks. “In other institutions, even when there are great resources available, there can often be many types of barriers to collaboration. But at UCLA, there are no barriers. It has been wonderful to work with great scientists and to teach such terrific students.”

Today, her lab is bustling. Funded in part by the National Institutes of Health and the California Institute for Regenerative Medicine, the state’s stem cell agency, and with a dedicated lab staff of 14 and growing, Crooks is tackling head-on many of the challenges about bone marrow transplantation, or BMT.

Though often thought of as strictly a surgical procedure, bone marrow transplantation is more like a blood transfusion. Within the billions of cells that are infused into a patient during the transplant process, there are only a comparatively few blood stem cells (averaging about one in 100,000), and of those, only a few will survive. Yet it is these stem cells that are the key. They will eventually self-renew, to become the driving engine that creates what Crooks describes as “a new immune system.”

For Crooks, it is precisely this mystery of how stem cells create this new immune system that is at the heart of her lab’s current line of scientific inquiry.

“The process of BMT is long and often punishing for both young and adult patients. We need to improve the way that BMT works so that the newly infused stem cells do not react against the patient—which in some cases can prove fatal,” explained Crooks. “Physicians still can’t predict or control exactly how well the immune system will work after each BMT. One of the primary goals of our ongoing research is to understand the exquisite mechanisms that allow stem cells to produce exactly the right number and type of lymphoid cells to re-create the immune system after BMT.”

Crooks’ lab is also at the forefront of a cutting-edge area of BMT research—investigating the effect that the thymus, a specialized organ of the immune system, has on the transplantation process. The thymus orchestrates the T cells of the immune system and, Crooks believes, unlocking its secrets offers the potential for many exciting new treatments for immune deficiency and a significant improvement in overall BMT success rates.

“The thymus is an infrequently mentioned and oft-misunderstood aspect of human cell biology,” said Crooks. “The success rates of BMT vary significantly, based on the type of disease and particularly on the age of the patient. A new immune system often does not mature well in older patients, while success rates for patients in infancy are much better. We want to understand why the young thymus functions so much better than in older patients. We think that the answer to this question may lie in the unique features of the microenvironment in the young thymus.-the soil in which the stem cell seeds from the bone marrow must grow."

When not in her lab, Crooks likes to spend time outdoors with her husband, also a BMT physician, or indulging in her hobby of pottery. Following in the family footsteps is her daughter, 20, who hopes to pursue a career in medicine and science, while her son, 18, is an aspiring filmmaker.

With over two decades of experience in her field, Crooks remains as excited as ever about the possibilities of scientific research, and is still infused with the same optimism as the wide-eyed young girl that once watched her favorite doctor on television.

“This is such a great time to be working in science and medicine” said Crooks. “Every day, new connections are being discovered between stem cells, cancer and the immune system. This realization has allowed scientists from many different disciplines to work together to tackle old problems in new ways. We hope that what we accomplish in bone marrow transplantation and stem cell research today can impact not just cancer, but many other fields of research and treatment.”

— Peter M. Bracke, 2012