Webinars Archive

Dr. Greg Palmer, Dr. Yvonne Mowery, Dr. Ashlyn Rickard | Evaluating the Effects of Papaverine on Tumor Oxygenation and Radiosensitization in E0771 Breast Cancer and Primary Sarcoma Mouse Models Using JIVA-25 | O2M Webinar Series

Recorded: May 2, 2022

About the Speakers

Greg Palmer obtained his B.S. in Biomedical Engineering from Marquette University in 2000, after which he obtained his Ph.D. in BME from the University of Wisconsin, Madison. He is currently an Associate Professor in the Department of Radiation Oncology, Cancer Biology Division at Duke University Medical Center. 

Yvonne M. Mowery, MD, PhD, DABR is a physician scientist and the Butler Harris Assistant Professor or Radiation Oncology at Duke University, specializing in treating head and neck cancer with radiotherapy and studying novel combinations of radiation with immunotherapy. She received her MD and PhD in Pathology at Duke University in 2012, followed by completing an Internal Medicine internship and Radiation Oncology residency at Duke University in 2017. She is the PI of an investigator-initiated phase I trial (NCT04576091) evaluating the ATR inhibitor BAY 1895344 with pembrolizumab and stereotactic body radiation therapy for recurrent HNSCC.

Ashlyn Rickard, PhD, received her doctoral degree in Medical Physics at Duke University in 2022, where she specialized in diagnostic imaging systems and radiation biology. In the Radiation Oncology laboratory of her PhD advisor, Gregory Palmer, PhD, she studies tissue-oxygen-imaging techniques using optical nanoprobes, Cherenkov emission imaging and electron paramagnetic resonance oxygen imaging. Because oxygen imaging has clinical implications in cancer research and radiation biology, most studies included radiation therapy and other anti-cancer therapies.

About the Webinar: Hypoxia, a prevalent characteristic of most solid, malignant tumors, contributes to diminished therapeutic responses and more aggressive phenotypes. The major challenge in implementing hypoxic radiosensitizers is the lack of a high-resolution imaging modality that can directly quantify tissue oxygen concentration. A precommercial EPR oxygen-imager was used to quantify tumor hypoxia and investigate the hypoxia-modifying effects of the FDA-approved vasodilator papaverine (PPV). We aimed to quantify the change in absolute tumor hypoxia induced by papaverine in two murine tumor models: E0771 syngeneic mammary carcinoma and primary p53/MCA sarcomas. We hypothesized that 1) there is a PPV dose-related change in tissue pO2, 2) papaverine radiosensitizes tumors, increasing tumor control and survival probability, and 3) pre-screening tumors for baseline tumor hypoxia by EPR imaging predicts radiosensitization in response to PPV. We report that papaverine alters tumor hypoxia in the breast cancer model with an average 47.5% increase in median tumor pO2 and an average 7.8% decrease in tumor hypoxic fraction.


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