An undergraduate sophomore from Gordon College in Massachusetts, studies the dependence of pancreatic cancer on the neuropilin-2 receptor for neovascularization. Studies were performed in the Vascular Biology Program at Boston Children’s Hospital and Harvard Medical School in conjunction with the Dana Farber/Harvard Cancer Center and The Continuing Umbrella of Research Experiences (CURE) Program.
Over the past 3 months I have been honored to study and work in a contemporary laboratory at Boston Children’s Hospital thanks to the generosity of the Summer Research Opportunity Program in Pathology (SROPP) sponsored by the American Society for Investigative Pathology (ASIP). I was mentored and supervised daily by Dr. Diane Bielenberg, Ph.D., a cancer biologist in the Vascular Biology Program at Boston Children’s Hospital. My summer experience was enriched by participating in the Continuing Umbrella of Research Experiences (CURE) Program at the Dana Farber Harvard Cancer Center where I was immersed in a diverse community of nearly seventy summer students.
The majority of my time was spent in the laboratory. My project focused on studying cancer biology and metastasis. Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate due to lack of detection, tendency to metastasize to the liver, and the absence of effective treatments. Consequently, there is an urgent need to develop drugs to inhibit PDAC progression. Neuropilin-2 (Nrp2) is a transmembrane receptor that binds an angiogenic ligand, Vascular Endothelial Growth Factor, and a repulsive protein, Semaphorin-3F (SEMA3F). Nrp2 is highly overexpressed in PDAC cells and PDAC-associated endothelial cells. Previous preclinical trials demonstrated that silencing Nrp2 in PDAC cells or targeting Nrp2 with neutralizing antibodies inhibited cancer progression. We hypothesized that PDAC tumors require vascular expression of Nrp2 in order to grow in vivo and tested this hypothesis by injecting syngeneic tumors into genetically altered mice and measuring tumor growth and angiogenic potential. Luciferase-labeled Panc0H7 mouse PDAC cells were injected orthotopically into the pancreas of mice, and tumor growth/metastasis was monitored via luminescence. Vascular density, measured by immunohistochemistry for CD31, was analyzed in normal pancreas and PDAC tumors and compared between Nrp2+/+ wildtype (WT) and Nrp2-/- knockout (KO) mice. Our results indicated that the static endothelium in the normal pancreas of adult mice lack Nrp2 and baseline vascular density was comparable between WT and KO mice. However, Nrp2 expression was upregulated in angiogenic PDAC tumor vessels in WT mice. PDAC tumors grew poorly in Nrp2-lacking mice and showed reduced tumor microvessel density. We next analyzed tumor vascular density in PDAC treated with SEMA3F in vivo and our results indicate that SEMA3F is anti-angiogenic. Lastly, the direct effect of SEMA3F on PDAC tumor cells was analyzed in vitro in a migration assay. SEMA3F inhibited the migration of PDAC in a dose-dependent fashion. Taken together, our data suggests that Nrp2 may be an important target in both tumor cells and endothelial cells in PDAC tumors. Targeting of Nrp2 with antibodies or its inhibitory ligand may prevent liver mestasis.
Over the summer I learned many new techniques including sterile culture of tumor cells, immunohistochemistry to detect blood vessels in cryosections, quantifying blood vessel density using ImageJ, polymerase chain reaction (PCR), breeding and genotyping mice, orthotopic injection of cancer cells into the pancreas of mice, and xenogen imaging on live mice to detect luciferase-labelled tumor cells in vivo. Other weekly activities included seminars focused on cancer research and cancer treatment given by local experts, a journal club where we discussed cancer-related published articles from basic research to clinical trials, evening seminars that included a panel discussion on career opportunities in biomedical sciences, weekly laboratory meetings in which we took turns sharing our data, and a book club where we read and discussed The Immortal Life of Henrietta Lacks by Rebecca Skloot.
Personally, this summer internship provided by ASIP gave me the unique opportunity to gain hands-on laboratory experience in a fast-paced and energetic environment. I interacted daily with students, post-doctoral fellows, clinical fellows, and professors at every level. Most importantly this experience taught me to think carefully, to analyze my data critically, and to prepare my results in a timely manner. At the end of the summer, I prepared an abstract and presented my research in the form of an E-poster to the Harvard Community. I plan to present my studies at the upcoming ABRCMS meeting in 2018 and at Experimental Biology in 2019. My future goals are to continue a career in the health professions and to apply to medical school following my graduation from Gordon College in 2021.