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Shakira M. Nelson, PhD, MPH, Cancer Prevention Fellow at the National Cancer Institute


It is chiefly important to show the variety of career options for PhDs at the end of their graduate school journey. As part of this spotlight, I asked one of our Penn State alumni to answer some questions about her career journey up until this point.

Meet Dr. Shakira M. Nelson, cancer prevention fellow at the National Cancer Institute in Bethesda, MD. Nelson obtained a PhD in Pathobiology from Penn State, class of 2013. Her former advisor was Dr. K. Sandeep Prabhu.  She also recently received a MPH (Masters in Public Health) in Epidemiology from John Hopkins University.

How did you chose your degree program and what you like about your current career?
As an undergrad I majored in Microbiology (also at Penn State). When I graduated I had no clue what I wanted to do next and decided to enter the workforce. I was fortunate enough to land a contracting job at the Department of Health and Humans Services (DHHS) where I worked within the Pandemic Influenza Division. For two years, I was able to watch MDs and PhDs work together, and with other Divisions and Agencies and Congress, to protect the country against a future influenza pandemic. The more I worked, the greater my desire to move into a field of public health, working to protect those around me. At the end of two years, I felt ready to return to school and get my PhD.

My plan was to work in biological sciences, acquiring the background necessary to understand biological assays, cellular work, and mechanisms. I still wanted to focus on public health and humans, working on prevention of diseases, but I felt having this as a foundation would benefit me in the long run. Little did I know that a person in my future, while at Penn State, would open a door for me that would lead me directly to the work I wanted to do. Towards the end of my PhD, my attention turned back to wanting to work on humans. The animal studies I did as a PhD student showed me mechanisms and helped me establish myself as a scientist, but I still desired to try something new. More specifically, I wanted to work on analyzing human clinical trial data, working in the prevention of diseases, such as cancer. One of my thesis committee members was an alumnus of the Cancer Prevention Fellowship Program, a prestigious fellowship offered through the National Cancer Institute. I was encouraged to apply. After reading their mission statement, I felt this would be a great fit for me. It would help me transition from biological sciences towards epidemiology, while allowing me to have experiences that would enhance my portfolio of knowledge and help with career development. I am currently in the third year of my four year fellowship, and it has been incredibly beneficial and fulfilling. I have met many people within the field of epidemiology who have been pioneers in the development of treatments and prevention methods of cancer development, including Dr. Harold Varmus and Dr. Douglas Lowy. I have traveled to conferences and networked with scientists and epidemiologist who work around the world and throughout the government, including CDC, NIH, and USDA. I look forward to the next steps in my career development, where I hope to continue working in the area of cancer prevention.

What have been some obstacles you’ve had to overcome in pursuit of your educational and career goals?
Many times I have had to get out of my own way. I used to worry a lot about not being smart enough, or not knowing enough about a subject, holding myself back from applying to a program or pursing an interest. I have had to learn to trust myself and understand the desire to learn is a trait that has taken me far. I continue to learn daily, and cast aside self-doubt, pursing opportunities as they become available.

What have been some sources of inspiration both in your career and in your life?
My sisters and parents have been my best source of inspiration. Watching my sisters vigorously pursue their educations and opportunities for development, as I have done to this point and time, has pushed me to continue to work hard, to be the best example for them I can be. I also appreciate the support of my parents, and how my accomplishments are a reflection of the upbringing I had and the dedication they had to raising my sisters and me.

What would you describe as your strong suit?
I think my best strong suit is my dedication to any project or task I begin working on. I push myself very hard, but not because I want to outpace anyone, but because I want to make sure this opportunity is going to make me more knowledgeable and be a useful skill in my future. When I start a project I like to give all my efforts and focus until it is completed. By giving my efforts in the manner I do, I know that my work ethic and talents will be seen in the final product of any project I work on.

How has Penn State impacted your life?
I spent a total of 10 years as a student at Penn State (as an undergraduate and graduate student). Over those 10 years I was able to see the necessity of my becoming an African American female PhD. There are so few women in the STEM fields, and even fewer minority women. To be at Penn State and be visible to both the undergraduate and graduate communities helped me to see how important my accomplishments can be and how it can help open doors to future minority females interested in pursuing a graduate degree.

What advice would you give someone who would like to pursue a career in your field?
Be patient. Projects move slow, advisors and students can give you a hard time; there are hundreds of reasons you’ll want to quit. But you are here for a purpose and part of your journey is overcoming these obstacles. Having patience is your best ally, and will help you go stronger in the long run.

What are your words of wisdom for current graduate students?
Enjoy your time as a graduate student and accept opportunities as they are presented to you. Your potential can only go as far as the opportunities you take advantage of. And although everyday can be a struggle (as usually is), this journey towards your PhD can be the example for someone else, helping them in an unexpected way.

What are your plans for the future?
I would like to stay within the government, working in the area of cancer prevention. During my time as a Cancer Prevention Fellow, I have focused on nutrients, diet, and prostate cancer. I am interested in staying in this area, as there is a lot of research that still needs to be done. I have also begun working in the area of health disparities, examining how this plays a role along the cancer continuum. Although I have veered away from academia (for now), I would like to continue to be involved with student mentoring, helping to bring minority and female students to STEM, providing a substantial impact in the field.

I asked Dr. Nelson to include a brief overview of her thesis work to hear about some of the interesting science that has happened at Penn State:
My work focused on selenium, an essential micronutrient with anti-inflammatory properties, that plays a vital role in many metabolic pathways. The true physiological significance of this micronutrient is heavily studied, where over 25 selenoproteins have been identified. The goal of my thesis was to understand the role selenium plays in anti-inflammation first using an ex-vivo model, with bone marrow-derived macrophage cells from mice fed varying selenium diets. Collected cells were treated with the bacterial endotoxin, LPS, to induce inflammation, or as the Th2-cytokine IL-4. My studies found that macrophages supplemented with adequate levels of selenium (100 uM) and treated with IL-4 increased the expression of alternatively activated macrophage markers, Arg-1, Ym1 and Fizz1. These alternatively activated macrophages are found in anti-inflammatory settings, and also play a role in wound healing.

Interestingly, in macrophages treated with LPS and supplemented with adequate levels of selenium, we saw a marked decreased in pro-inflammatory macrophage markers iNOS, TNFa, and IFNg. Together these studies suggested that selenium at an adequate level can shift macrophages from a pro-inflammatory towards an anti-inflammatory phenotype. To effectively translate these findings into an animal model, we collaborated with Dr. Joseph Urban from USDA using the helminthic gastrointestinal parasite Nippostrongylus brasiliensis (Nb). These parasites have a short life cycle, residing in the lungs for 1-2 days before arriving in the small intestine where they reside until 14 days after initial infection. Mice infected with Nb and supplemented with Se significantly increased the expression of the alternatively activated macrophage markers Arg-I, Ym1, and Fizz1 in the small intestines, while decreasing the presence of intestinal worms and fecal eggs. We found that the experiments conducted in my dissertation suggest that optimal Se status, in the form of selenoproteins, is critical to shunt macrophage activation towards an alternatively activated phenotype that promotes enhanced clearance of gastrointestinal parasites.


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