|Patricia Dahia, M.D., Ph.D., received $200,000 in funding from the Sidney Kimmel Foundation for Cancer Research. |
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Just as too much sugar in the diet can make a person grow larger, scientists at The University of Texas Health Science Center at San Antonio are studying why some cancer cells grow by using sugar instead of oxygen, as normal cells do. The theory, called the “Warburg effect,” could be an important link in understanding how cancerous cells grow faster than normal cells.Kimmel Scholar Award to fund research
The research is being funded in part by a new $200,000, two-year Kimmel Scholar Award presented to Patricia Dahia, M.D., Ph.D., an assistant professor who has been studying this recently revived and controversial hot topic in cancer research.
Dr. Dahia is an assistant professor who works in the division of hematology and medical oncology of the department of medicine, and in the department of cellular and structural biology. She is a member of the San Antonio Cancer Institute, one of only two NCI-designated cancer centers in Texas, which also is a sponsor of Dr. Dahia’s research. As one of only 15 researchers in the nation to receive the Kimmel Scholar Award this year, she is considered by the Sidney Kimmel Foundation for Cancer Research to be “among the nation’s most promising young cancer researchers.” While many funding organizations give substantial awards to only established researchers, the Kimmel Scholar Awards are intended to encourage cancer researchers early in their careers. The focus of the award is to improve basic understanding of cancer biology and to develop new methods of preventing and treating cancer.A theory of paradoxes
The theory of cancer cells using sugar to produce energy for growth was first observed in the 1920s by German researcher Dr. Otto Warburg. While Warburg’s theory, called aerobic glycolysis, was rejected at the time, it was resurrected in the last decade by scientists interested in learning more about how cancer cells produce energy and use it to grow and divide.
Dr. Warburg’s theory is full of paradoxes. For one, the process normal cells use to produce energy by using oxygen, called respiration, seems at first glance to be much more efficient than using sugar. Thirty-six molecules of adenosine triphosphate (ATP) — a molecule that stores energy — are produced in the chemical reaction using oxygen. Only two ATP molecules are made using glycolysis.
Even stranger is that some cancer cells prefer using the sugar method, even when oxygen is available.
“It appears that the glycolysis process is less efficient, but faster,” explained Dr. Dahia. “Cancer cells try to circumvent all normal ways to control growth because they are fighting for survival.
“We don’t really understand yet why this shift in metabolism happens,” she added. “Some cancer cells don’t get enough oxygen, their mitochondrial machinery (where the energy is produced) could be different from normal cells or it may be a combination of these factors,” she added.Research models
An endocrinologist, Dr. Dahia plans to use several models to study glycolysis, including her longtime research focus, pheochromocytoma, called “pheo” for short. Pheo is a type of tumor that grows in the adrenal glands. Usually benign, the tumors cause the adrenal glands to produce too much adrenaline. They also can cause high blood pressure, pounding headaches, heart palpitations and nausea. An adrenal gland sits atop each kidney. Some pheos are caused by mutations in genes that function in the energy metabolism, known as succinate dehydrogenase (SDH). These tumors are hereditary, which make them an ideal model to study the Warburg effect and the connection between shifts in the energy metabolism and cancer. Dr. Dahia has been studying this type of tumor for 10 years and has collected more than 400 tissue samples from researchers through an international consortium.
Dr. Dahia also plans to study the disease in mouse models and in cell lines produced in the laboratory to mimic what is observed in human patients.Collaboration
Dr. Dahia plans to work in collaboration with Health Science Center researchers to take advantage of their complimentary expertise and the available technologies required for this research. The researchers include Susan Weintraub, Ph.D., professor of biochemistry and director of the Gas Chromatography and Mass Spectrometry Core facility; Andrew Hinck, Ph.D., associate professor of biochemistry, who manages the Nuclear Magnetic Resonance spectroscopy technology; Holly vanRemmen, Ph.D., associate professor of cellular and structural biology and director of the Oxidative Stress Core; and Kris Vogel, Ph.D., assistant professor of cellular and structural biology, who works with animal models of cancer.
“I am honored to receive the Kimmel Scholar Award,” Dr. Dahia said. “These studies may help to lay the groundwork for a new approach for cancer therapy that targets the metabolism of tumor cells and which has the potential to be applied to a broad group of cancers.”