The Cancer Moonshot: Dr. Christopher Pennell on Cancer Research and Treatment

When President Obama delivered his final State of the Union address last month, he challenged Americans to channel the innovation and spirit that lead to putting a man on the moon to achieve the next great “moonshot”: finding a cure to cancer. In honor of the cancer moonshot, Health Talk will be drawing upon the vast knowledge of the researchers in the Masonic Cancer Center, University of Minnesota in an ongoing series dedicated to cancer research. To kick things off, we sat down with Christopher Pennell, Ph.D., Associate Professor in the Department of Laboratory Medicine and Pathology, to gain insight into the work he does at the Masonic Cancer Center and where cancer research is headed.

Health Talk (HT): What is your area of research and why did you focus on this area over any other one?
Christopher Pennell (CP): My areas of research are tumor immunology and tumor immunotherapy. These areas respectively address interactions between tumors and the immune system, and how we can exploit the immune system to treat malignant tumors (cancers).

I focused on this area because the immune system has evolved to be exquisitely specific, and specificity is the holy grail of cancer therapy. If a therapeutic agent kills only tumor cells, and not normal cells, then the therapy has very low toxic side effects and a relatively large therapeutic potential. The immune system can distinguish between highly related molecules, such as those expressed by malignant cells and the normal ones from which they were derived. So specificity is one aspect of the immune system that makes it attractive for cancer therapy. The other two are potency and memory. This combination of specificity, potency and memory is ideally suited for cancer therapy.

HT: What is your role at the Masonic Cancer Center, University of Minnesota?
CP: I have several roles at the Masonic Cancer Center (MCC). I was recently named the Associate Director of Education and Community Engagement. My primary goal in this role is to develop mutually beneficial relationships between MCC and Minnesota residents that reduce the burden of cancer in Minnesota. To achieve this goal I lead a team that engages with community organizations. We hope to become better educated as to their concerns and needs regarding cancer. If the MCC has programs in place that already meet these needs, then we share that information. If not, then we bring these issues to MCC leadership to inform new initiatives and directions. My other roles in MCC include serving on our Scientific Council, Executive Council and as an MCC representative on the faculty advisory committee for the University Flow Cytometry Resource Core.

HT: Cancer is something that either directly or indirectly affects the lives of many people around the world. Because it’s so prevalent, the average person might know more about cancer than other diseases. What is something that is often overlooked?
CP: Something that is often overlooked is that cancer is not a single disease. Cancer is an umbrella term that describes hundreds of different diseases. As such, there cannot be a single cure for all cancers, just as there is not a single cure for all infections (because infections result from many different viruses and bacteria, all with different biologies). All cancers share two characteristics, though: uncontrolled proliferation and metastasis (spread). Uncontrolled proliferation is exploited by some drugs, such as chemotherapeutics, that kill rapidly dividing cells and so can be applied to many types of cancer. However, these drugs lack specificity and do not distinguish between normal cells that are rapidly dividing naturally, and malignant cells that are rapidly dividing aberrantly.

HT: You were instrumental in programming the upcoming Mini Medical School session at the University of Minnesota. How did you determine which areas of cancer research to focus on?
CP: I have to give a lot of credit to my MCC colleague, Jim McCarthy. He and I bumped into each other the day after we received the wonderful news that cancer was the topic chosen for the upcoming Mini Med session. Jim is an outstanding experimentalist and teacher, and I highly value his opinions. So I asked for his thoughts on how to organize the sessions. We had a 30-45 minute impromptu conversation about what areas to choose, and how to structure the series to provide continuity both within and between the five sessions. We arranged the topics to lead the audience in a stepwise manner to a deeper understanding of cancer research, and how the knowledge gleaned from research impacts cancer prevention, therapy and patient care. We start with Cancer 101, proceed through key areas such as how mutations and aberrant cell signaling relate to cancer, then it’s on to new therapies in people and pets, and we end with quality of life issues. All of these areas are ones in which MCC has existing programs and strengths.

HT: How has cancer research changed over the years? Have interdisciplinary collaborations grown? What are the benefits to these types of collaboration?
CP: Cancer research has changed significantly over the years due to improvements in technology and the recognized need for interdisciplinary collaborations. An example of the former is in gene sequencing. It took years and over a hundred million dollars to sequence the first human genome. Now a human genome can be sequenced in days for about $1,000. We are awash in data, which is both good and challenging.

The recognized need for interdisciplinary collaborations has evolved from our appreciation of cancer’s complexity. No one person has all the knowledge and tools needed to tackle cancer. So we talk to one another. The cool thing is that scientists get excited when we learn new things; successful new collaborations are mutually beneficial and stimulating to the investigators involved. The net result is often a novel finding that impacts the field.

HT: What’s on the horizon for cancer research?
CP: Cancer therapy is ever-evolving. We have gone from non-specific therapies (e.g. chemotherapy), to tumor-specific therapies (e.g. Gleevec for chronic myelogenous leukemia), and now to targeted, patient-specific precision therapies. Our ultimate goal is to identify a unique feature of a tumor, relative to the normal cells from which it derives, that can be targeted for therapy. Ideally we’d like to identify several such features to target simultaneously to reduce the likelihood of the tumor developing resistance to any one drug. To summarize, the field is moving towards combination targeted therapy that is patient-specific. To achieve this, we need to combine genetic, pharmacological and immunological approaches, and to have collaborations that span the biomedical spectrum from basic to translational to clinical research. This is what we do at MCC.