By Sage Wesenberg, Biochemistry and Journalism 2019

Northeastern’s accomplished chemistry professor, Paul Vouros, is retiring this December after 42 years of teaching and research. His work developing chromatographic methods coupled with mass spectrometry, has led him to many research applications and collaborations around the world. Much of his interest has been in the detection and quantitation of biomarkers associated with DNA damage from the interaction of carcinogens from a variety of sources, ranging from environmental and radiation exposure to the cooking of food. With his expertise in the field of mass spectrometry, Vouros has incorporated his research into the classes that he has taught, along with mentoring many undergraduate, PhD, and Master’s students throughout his many years here.

Vouros was born in Thessaloniki, Greece, and grew up as a young child during both World War II and the Greek Civil War that immediately followed. He recalled vivid memories of his house being bombed when he was only six years old; thankfully his family was evicted from it a few months earlier as it had been taken over by the occupation forces. After attending public elementary school he was admitted to Anatolia High School in Thessaloniki, a school founded originally by American missionaries in Asia Minor. It was here where he discovered his passion for chemistry that led him on his path to Northeastern many years later. Anatolia has a college level program now, called the American College of Thessaloniki. Every year, Northeastern sends NUin freshmen there. Vouros recently found out that Professor Thomas Gilbert, whose office just happens to be one door over from his own, is coordinating the chemistry program there.

After high school, Vouros came to the United States in 1957 on a Fulbright Scholarship and the dean of his high school recommended he attend his alma mater, Wesleyan University in Connecticut where he majored in chemistry and minored in German. His undergraduate thesis under Professor John W. Sease explored the stereoselective synthesis of organic compounds by electrochemistry using a mercury electrode as a blocking group. It was here that he was also first exposed to the then still emerging technique of gas chromatography with a thermal conductivity detector that he used to analyze his reaction products. After graduating from Wesleyan, Vouros attended MIT with the intent to further his studies in the field of electrochemistry, by working with a specific professor there. However, his intended mentor ended up leaving MIT the very same fall that Vouros arrived, and as he said, “It turns out he did me a huge favor.” Subsequently, Vouros met Klaus Biemann, an MIT professor regarded as the “father of modern mass spectrometry,” In addition to providing a rigorous environment for research, “Biemann also showed all of us the importance of human interactions,” Vouros said. This graduate school experience played a major role in his decision to become a professor himself. After MIT, he spent five-and-a-half years at Baylor Medical School in Houston, Texas at the Institute for Lipid Research headed by Professors Evan and Marjorie Horning. Here, he was further exposed to the technique of mass spectrometry. “I learned how to apply the techniques to biomedical and biochemical problems, rather than just looking at fundamental topics. It was an eye opener,” he said. While in Houston, Vouros saw a Northeastern advertisement for a position in a new institute for forensic research. Under the leadership of Professor Barry Karger the institute evolved into the now world famous Barnett Institute of Chemical and Biological Analysis. He said that “… being part of the Institute and in a stimulating research environment that involved close interaction and scientific collaboration with the original nucleus of the Institute comprised by Barry Karger, Roger Giese, and the late Bill Giessen was one of the most rewarding experiences in my career.” Even though the forensic program’s funding got dropped a year later, Vouros was already on his way to generate independent research support which over the years produced grants from agencies like the NIH, EPA, DOD, and industry that helped set the foundation for Northeastern’s mass spectrometry program.

Throughout his career, Vouros has completed extensive amounts of research, with over 250 peer reviewed publications. Before coming to Northeastern, his work at Baylor focused mostly on the use of gas chromatography – mass spectrometry for steroid and drug analysis. In the process he was exposed to the medical applications of these techniques, including the monitoring of the transfer of drugs from a mother to her newborn child. Many of the chemical derivatization techniques he investigated during those years are still relevant, and he has applied them in collaboration with colleagues at Brown Medical School to elucidate the structures of novel Vitamin D analogues and related steroids.

Another major area of his research has focused on analyzing a variety of carcinogenic biomarkers, known as DNA adducts, that are associated with DNA damage. For this purpose he relied on the use of micro-capillary and nanoscale LC as well as capillary zone electrophoresis coupled with MS. He and his students kept continually refining these techniques over the years in order to meet the increasing analytical demands. He initially focused his research on DNA biomarkers associated with carcinogens from environmental pollution. However, while on sabbatical in Switzerland, he was invited to present a seminar at Nestle where his results drew the attention of Dr. Robert Turesky, a senior scientist at Nestle, now in the faculty of the University of Minnesota. Dr. Turesky pointed out to him the potential value of his methodology to the food industry. For example, when food with high protein content like meat is cooked at high temperatures, organic compounds known as heterocyclic aromatic amines, are formed which are then metabolized in our body after consumption. These metabolites have the potential to turn into agents that attack and modify DNA, thereby increasing the potential risk for cancers. Vouros views his interaction with Dr. Turesky as a highlight of his research in this area and values their continuing close personal and professional relationship.

“Through good sound chemistry, I felt I was able to open doors to look into different biological issues,” Vouros said, as he described how his research on 4-aminobiphenyl a tobacco carcinogen and important bladder cancer inducer drew the attention of Dr. Yuesheng Zhang an oncologist at the Roswell Park Cancer Institute in Buffalo, NY in 2006. After a meeting in Buffalo with two of his Ph.D. students to share their findings in more detail, Vouros started a collaboration with Dr. Zhang which is still continuing 10 years later with the involvement of four generations of Ph.D. students. An intriguing finding in their early studies was the observation that the levels of biomarkers associated with DNA damage were significantly higher in male than female mice, consistent with epidemiological data in humans. They are now investigating the effects of specific hormones in the mice to hopefully explain these gender effects. They have also exposed mice to components of broccoli, which have anticarcinogenic properties, and showed that DNA damage could be blocked. Much of this work is still in the beginning of a long process. While Vouros will retire and take a back seat on this project, it is expected that Dr. Zhang will continue this research in collaboration with previous Ph.D. students or other colleagues of Professor Vouros.

Much of Vouros’ research has relied on the use of nanoLC-MS to achieve very high sensitivity levels for the quantitation of biomarkers. However, speed of analysis still remained a challenge, as most chromatographic analyses tend to be too time consuming. Nearly 10 years ago, with funding from SIONEX Corporation in Bedford, MA, his lab initiated an investigation on the analytical capabilities of the very new technique of differential mobility spectrometry (DMS). In a series of papers in collaboration with Dr. Erkinjon Nazarev one of the original inventors of DMS and Dr. Stephen Coy visiting scientist in the Vouros lab, Vouros and his students showed that DMS-MS can serve as an alternative (or complement) to LC-MS. Most importantly DMS-MS has provided a means for ultrarapid quantitation of biomarkers by effectively reducing the analysis time to a fraction of that consumed by LC-MS. This work has led to a very exciting collaboration with Professor Albert Fornace of Georgetown University that has taken his analytical chemistry work in yet another direction. Using liquid chromatography and electrochemical detection, researchers at Georgetown screen urine or blood in search of compounds that may serve as biomarkers of radiation damage. Once they have identified potential candidates, Vouros and his students take over to apply their ultra-rapid methods of analysis in order to quantify their levels in subjects exposed to potentially dangerous conditions. This project is still in the works with several forthcoming publications describing promising in vivo results from non-human primate samples provided by Georgetown. Human studies have been approved and are currently under way.

Outside the lab, Vouros has taught a variety of chemistry classes. Since 1978, he has taught courses in general chemistry, analytical chemistry, analytical biotechnology, and a graduate course in mass spectrometry. In all of his classes, he has tried to bring his research experiences into the classroom, especially in the analytical chemistry and graduate courses. Out of the many classes he has taught, his favorite over the years has been the graduate class. It has drawn a lot of students from the local biotechnology community many of whom may already have had practical experience with mass spectrometry in their jobs. “Sometimes, they were even more current on things than I was, and always brought interesting questions to class. It provided a source for interesting and challenging discussions that was motivating for me – and the class,” Vouros said. And while the class size fluctuates every year, sometimes more than 50, and other years about 20, Vouros said the students have always been engaged and excited to learn about the techniques, the fundamentals and their applications.

Professor Vouros has very much enjoyed his time working at Northeastern. He also has some very fond memories of his teaching general chemistry during his early years when Northeastern was noted for its high population of commuting students. Vouros was intrigued by their motivation and the drive to learn that he saw in those students. “I remember seeing students who came in the morning, people who had worked all night long, and they were there, eager to work for an eight a.m. class. I could see a young kid killing himself to be here, and do well, so I knew I had to deliver. It was very energizing.”

Over the course of many years of research and teaching, Vouros said his favorite part has been working with young people and young minds. His graduate years at MIT and his advisor Professor Biemann showed him that in addition to being focused and rigorous in his research, it was also very important to bond with students. “My sense is that I accomplished that,” Vouros said, “I think it was very nice to create a family atmosphere in the lab. The close interaction with students is a very important aspect of the academic research.” Chemistry department chair Michael Pollastri agrees. “I know of no other faculty member with such a loyal following of students and trainees, and, to me, this speaks volumes to his impact upon science writ large,” he said. Vouros described the annual barbecue he and his wife had every year at their home and neighborhood pond, where many of his past and current graduate students and their families would join together for a day of fun, tennis, and swimming. He became aware of the reality of the passage of time about five years ago when of one of his first students, brought his daughter to the party; she was starting school at Northeastern in the fall. With close to 50 Ph.D. students and several Master’s students, Vouros has worked with many students at Northeastern, and has many people to carry on his work as he prepares to retire. His office is filled with research papers and photographs, and a bookshelf in the corner that holds the volumes of his Ph.D. students’ theses.

“The first thing to do when I retire will be to clean up this office,” he said, “I haven’t quite figured out what to do with them yet, but I know these theses are important to my students and a lot of great work went into them.” Vouros is still working on finishing up publications from some students’ past research. He plans to wrap those up in the next couple of years to honor those students more so than his own actual research.
Pollastri spoke quite highly of Vouros and his many accomplishments over the years. He said, “Paul has had a profound impact on science that goes well beyond the achievements seen through his published work. His dedication to mentorship and teaching has equipped countless students with the knowledge needed to shape the future of scientific discovery. On a personal level, I am grateful for Paul for his wonderful and warm support as a colleague. He always has a smile and an upbeat story to share whenever I see him, and I’ll miss those encounters after he retires.”

As his retirement approaches, Vouros has many exciting things to look forward to. He talked about having more relaxed time to enjoy his family—his wife Irene of 51+ years, their daughters, and four grandchildren who live nearby. He plans to put his memories of growing up in Greece during WWII and the years soon after into writing for his grandchildren to have. And he certainly looks forward to following the literature about ongoing research and new developments in “adductomics”, but now from a different vantage point. He may also continue to serve as subject editor for Mass Spectrometry Reviews, a leading journal in the field of mass spectrometry. And, if he now sneaks out on a Friday afternoon to Symphony Hall or to a Red Sox game he will no longer experience any guilty feelings!