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School of Medicine
Elias Zambidis on balancing a career as a physician researcher:
As a physician researcher, you are both a pediatric oncologist and a stem cell biologist. How do you balance these two jobs?
ZAMBIDIS: Right from the beginning of my training, I knew I wanted to take care of patients and do research, which is why I got both an M.D. and Ph.D. Now, I spend one month a year working in the inpatient ward that provides care to about 15 to 25 critically ill children at any one time. The rest of the year, I dedicate half a day to the clinic each week and the remainder of my time I spend in the lab. When I’m gone from lab, I delegate responsibilities to my scientists.
I see being a physician and researcher as interrelated because each part complements and inspires the other. Some of the research questions that I think of stem from observations I make in the clinic. I try to think about how disease can be studied on a more basic level in the lab.
Is Johns Hopkins an ideal place to combine research with the clinic?
ZAMBIDIS: A place like Hopkins truly supports the physician scientist, which is one of the reasons that I chose to train here. Hopkins is famous for building and nurturing the physician scientist.
I looked at other places and it was much harder to pursue a career where you could do both research and treat patients. Other places are smaller and you don’t have the luxury of being a scientist if you are taking care of patients because there aren’t enough doctors to go around. Hopkins is a large enough place that you can share the clinical duties with other doctors in a team approach.
What is your research focus?
ZAMBIDIS: We study stem cells to learn how cancer starts. For example, leukemia starts with a type of blood stem cell that just keeps growing and dividing without any regulation. In contrast, normal stem cells only grow and divide in a regulated way to fix or replace aging or damaged tissue. If we can understand normal stem cell regulation, then we can understand what goes wrong in faulty stem cells that give rise to cancers.
We are also interested in induced pluripotent stem (iPS) cells, where researchers use defined genetic factors to turn back the clock of an adult cell until the cell reaches an embryonic-like state that can give rise to all the cells in our bodies. My scientific group believes that the same machinery that can artificially turn a skin cell back into a stem cell is also used abnormally when cells develop into cancers like colon or breast cancers or leukemia. There is a conversion from a differentiated to an undifferentiated stem cell-like state in the development of diseases.
We are interested in the components of the cell machinery that determine pluripotency—the ability to become other cell types. Some of the players of this machinery are known and are referred to as the ‘core embryonic stem cell network.’ But, we really only understand the tip of the iceberg. There are still groups of related proteins known to affect pluripotency, but whose interactions with other proteins are completely unknown. We are trying to blaze a trail to discover new interactions to this stem cell machinery to understand how stem cells are regulated.
--Interviewed by Vanessa McMains
Elias Zambidis on using stem cells to study cancer: