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Meet the Scientists

Photo of David Kirsch, M.D., Ph.D.

David Kirsch, M.D., Ph.D.

  • Associate Professor in the Department of Radiation Oncology
  • Associate Professor in the Department of Pharmacology & Cancer Biology

I am a physician scientist. I use radiation therapy to treat patients with cancer. In my lab, we study how radiation therapy cures cancer and causes side effects. For example, we are studying how radiation can cause cancer. This is important not only for patients treated with radiation therapy, but also for astronauts, who are exposed to radiation while traveling in space.

During medical school, I completed a PhD studying how cells die following stresses like radiation. After completing my clinical training as a radiation oncologist, I continued my research as a post-doctoral fellow at M.I.T. using genetically engineered mice as a model system. I developed a new mouse model of a muscle tumors (called sarcomas) that my own lab still uses to study cancer development, metastasis, and novel cancer therapies. To study which cell types are important for mediating normal tissue injury from radiation, I deleting genes in a cell-type specific manner in the mouse to study how radiation causes normal tissue injury.

When I moved to Duke to start my own lab, I continued to use the genetically engineered mice to study radiation biology. For example, we are using mice to modify the levels of the p53 tumor suppressor to determine how p53 regulates radiation-induced cancer from X-rays and from space radiation. To expose mice to space radiation, we send our mice from Duke to the Brookhaven National Laboratories in New York. You can find out more about my lab’s research at our website: www.kirschlab.org

When I am not at work, I enjoy spending time with my family including my 3 children and our puppy Gelato.


Photo of Mark Onaitis, M.D.

Mark Onaitis, M.D.

  • Associate Professor in the Department of Surgery

I am a surgeon researcher in the Division of Cardiothoracic Surgery. In my clinical practice, I perform lung resections to cure patients with lung cancer. In the laboratory, we study the cell-of-origin of lung cancer in order to better understand the molecular mechanisms that cause these cancers to form. The hope is that better understanding will lead to better treatments for lung cancer patients. This understanding will also help astronauts traveling in deep space in that preventative measures against lung cancer caused by radiation may be developed.

After finishing my surgical training at Duke, I spent some time with cell biologists and mouse modelers at Duke in order to learn approaches to alter genes specifically in lung epithelial cells. We have used special mice that allow changes to genes in respiratory epithelial cells but not in any other cells throughout the organs. Our NASA grant involves using these special mice to study which cells in the lungs form tumors after they are exposed to space radiation.

When I am not at work, I enjoy spending time with my family including my wife (who is also a surgeon) and my 2 boys (ages 5 and 7).


Photo of Barry R. Stripp, Ph.D.

Barry R. Stripp, Ph.D.

  • Professor of Medicine & Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles
  • Professor of Medicine, University of California Los Angeles
  • Adjunct Professor of Medicine and Cell Biology, Duke University Medical Center

I am a basic stem cell and developmental biologist at Cedars-Sinai Medical Center in Los Angeles. We use animal models and patient samples to understand how the lung is normally maintained and how disease leads to changes in lung function and structure. We study how radiation impacts normal tissue maintenance. This is important to understand the health effects of radiation exposure that astronauts would experience during long-term missions in space. The research also helps us understand how therapeutic radiation exposure leads to structural and functional changes to lung tissue that impact patient health.

A native of England, I moved to the US to do research in 1982. I have worked as a member of the faculty at the University of Rochester (NY), the University of Pittsburgh (PA), and Duke University (NC) and most recently at Cedars-Sinai Medical Center (CA). We are known for pioneering work studying lung stem/progenitor cells that contribute to normal lung maintenance and repair following injury. We actually use cells from genetically-modified mice to re-grow critical mouse and human lung structures in a dish!

Our NASA-supported research investigates how different types of radiation that are encountered on earth or in space impacts the ability of lung stem/progenitor cells to grow and generate specific cells that are critical for lung function. We study how certain proteins interact within cells and between cells to regulate their response to injury and radiation exposure. An important aspect of my lab is to help train the next generation of researchers in my field of research.

Activities I enjoy when not not at work include a range of outdoor activities from biking and hiking in the mountains to casual walks along the Southern California beaches and working in my garden.