Author: The Wistar Institute

Dr. Ian Tietjen came to Wistar in 2019 as a research assistant professor in the laboratory of Dr. Luis Montaner. He brings a fascinating approach to HIV and infectious disease research that explores the traditional medicine knowledge of Indigenous peoples and healers around the world in treating infection with natural substances.

“There is a wealth of information and experience that has been passed down through different cultures over generations and allowed people to maintain health and treat disease before the advent of modern medicine,” said Tietjen. “While a lot of this information can be anecdotal and sometimes inexplicable to scientists like us, we believe it could hold the key to powerful medicines. We want to apply our scientific method and currently available research technologies to find out.”

Many natural compounds have provided antiviral activity during evolution, for example to protect plants and other organisms that don’t have a specialized immune system like ours and use chemicals to fight viruses. Therefore, these substances could be repurposed as antivirals to support our immune response against infection.

Based on this idea, botanists and chemists began teaming up in the 1940s to create antiviral drugs using chemical compounds found in plants, and during the past 25 years, several screening programs have investigated the antiviral activity of medicinal plants.

Dr. Tietjen brought to Wistar a collection of compounds derived from plant and marine organisms that he obtained in collaboration with other researchers around the world and while working with traditional healers in different countries. The Montaner lab is now testing these substances for their ability to affect the immune response to HIV.

When COVID-19 started, Drs. Tietjen and Montaner decided to apply the same approach and comb through the library to look for antiviral activity against SARS-CoV-2. For example, they are testing for the ability of these compounds to disrupt the interaction between the viral Spike protein and the ACE2 receptor present on human cells — the lock and key mechanism that allows virus entry — in order to halt infection.

“So far, we’ve found several pure compounds that are able to do so in the laboratory,” said Tietjen. “We also identified several African medicinal plant extracts that disrupt this interaction.”

This was accomplished in collaboration with Joel Cassel in Wistar’s Molecular Screening Facility. Cassel successfully adapted a pre-existing assay for large-scale screening, which allowed the team to evaluate many compounds and find positive hits quickly. To confirm the screening results, they tested those hits against a different receptor/viral protein interaction, and many of them didn’t show activity in this experiment, indicating they specifically block the SARS-CoV-2 entry mechanism.

“Importantly, we are observing similar bioactivities in specimens of the same plant collected from different healers and in different locations, which supports that the bioactivity is intrinsic to the plant,” said Tietjen.

Some of the medicinal plant extracts are extremely potent, in some cases disrupting the Spike/ACE2 interaction at very low concentrations.

“One of our leads includes a species of Artemisia, a family of plants commonly known as mugwort, wormwood and sagebrush and well established as an antimalarial agent. Our observation is consistent with what others are reporting worldwide, although it’s way too early to recommend use of this plant to treat COVID-19,” said Tietjen.

He added that some healers in Southern Africa have administered some of the medicinal plants being tested at Wistar to community members that have been coming to them recently with respiratory infections, and they report having obtained benefits.

“This information is anecdotal, so we have to discuss our findings together and all agree on a plan to monitor these observations more closely,” Tietjen said. “This is the perfect example of the benefits of what we call ‘reverse pharmacology’ efforts — we obtain compounds and information by collaborating with traditional healers, test their products in the lab with our methods and share our results with them as the data are generated to inform their practices in real-time.”

Tietjen also emphasizes that collaborations with healers and their communities involves years of building relationships and trust. It also requires working together as equal partners and toward mutual knowledge benefits. “This exchange, being able to provide this kind of information to healers, and also learning about quite different but also valid ways to perform medicine are very rewarding aspects of this work,” he continued. “We can learn a lot from each other.”

In the lab, researchers are now confirming preliminary results using a SARS-CoV-2 pseudovirus — virus-like particles that have the essential components for infecting cells in culture but can’t replicate and cause further infection, representing safe tools to mimic SARS-CoV-2 virus for further studies.

Tietjen, Montaner and team are also working to determine if the hit compounds can block entry of the real SARS-CoV-2 into cells in vitro. This work can be done at Wistar in the BSL3 facility, which provides the required safety environment for handling airborne infectious diseases like coronaviruses.

Next, researchers plan to refine and optimize the most potent molecules to make them as selective and safe as possible.

A longer-term goal is to identify agents that can enhance the antiviral activity of existing drugs like remdesivir, along with those that could inhibit entry of other coronaviruses that use ACE2 for entry. Those leads would eventually go into animal models to test for in vivo efficacy.

“Our work looking for natural antivirals is worthwhile because, even when a SARS-CoV-2 vaccine becomes available, it won’t be accessible to everyone immediately, especially in resource-limited regions where people rely on traditional medicines and community healers for their health,” said Tietjen. “Also, since the world has been hit by different coronavirus outbreaks since 2003, it’s critical for us to build up our antiviral armamentarium and be prepared for the next potential coronavirus threat to human health.”

As our state economy faces a long slog back to recovery from the COVID-19 pandemic, Wistar is poised to assist with the development of the workforce that will help enable that recovery. The Institute’s education and training programs provide just what is needed for curious, intellectually minded students to establish careers as biomedical research technicians and pursue other careers in the life sciences. 

The Biomedical Technician Training (BTT) Program and the Biomedical Research Technician (BRT) Apprenticeship focus on giving students an accelerated career path with on-the-job training as biomedical research technicians.

The BTT Program was launched 20 years ago to develop the workforce in the biomedical and biopharmaceutical research sectors and provide hands-on training to students for two years at the lab bench to become research technicians. The experience brings science vividly to life and inspires many students to pursue advanced degrees or develop highly specialized biotechnology research skills through Wistar’s state-certified, non-traditional BRT Apprenticeship.

The BRT Apprenticeship gives interested BTT Program graduates nine additional months of intensive experience, building critical research skills and specialization through training in top biomedical research labs across the region. In 2019, the BRT Apprenticeship was awarded the Outstanding Non-traditional Apprenticeship Program of the year by the Pennsylvania Commonwealth’s Department of Labor & Industry. 

Wistar’s education and research training programs boast many stories of talented trainees who have matured into skilled scientists. Some of the BTT and BRT trainees are currently involved in laboratories working to understand more about COVID-19, having the opportunity to make a difference during this global health crisis.

Yaya Dia is one of them. He works in the Wistar lab of Dr. David Weiner and contributes to translational research taking place to advance a COVID-19 synthetic DNA vaccine which is being tested in clinical trials. Yaya trained in the Weiner lab during his BTT internship and is currently a BRT apprentice working in the lab on various projects and contributing to the vital research that led to his name added as a co-author on four papers. 

“It is a pleasure and privilege to work on the DNA vaccine that Dr. Weiner and my colleagues are advancing,” said Yaya. “I was in the right place at the right time to have this amazing experience. I carry out assays and tests to better understand the immune system and how it reacts to certain pathogens. I love that I get to better understand how the body works and how it fights diseases with the help of a DNA vaccine. It’s a great lab and a great team and Dr. Weiner really cares about the people he works with, which makes you want to work harder.” Yaya sees his next career step in science enrolling into a Physician Assistant program or medical school.

Jessicamarie Morris and Kwasi Gyampoh are BRT Apprenticeship graduates who work in the Wistar lab of Dr. Luis Montaner, who has been focusing on developing a cure for HIV and now is expanding his research activities to include discovering new therapies for COVID-19. With Dr. Montaner as their mentor, they have become sought-after and valued biomedical research technicians.

“I would have never been where I am without either program,” said Jessicamarie. “I had graduated college and felt I was done when it came to more schooling. I thought that traditional route was the only way to get into the science field. But I realized the BTT Program and the BRT Apprenticeship offer a novel entrance into science.”

She learned by doing and that paid off in spades.

“At Wistar, I experienced what it means to work in a real, functioning lab within a research institute. I was able to do so many different types of work and learned the ins and outs of different departments,” said Jessicamarie. “I became a lab manager and purchased scientific supplies, arranged meetings and interviews, and gained so much knowledge from my lab coworkers.”

“I had a great-uncle who died from AIDS in the early 2000s so I feel I can make a difference through working in an HIV research lab,” said Jessicamarie. “And I love the people I work with. Everyone is helpful and supportive.”

Kwasi, like Jessicamarie, graduated from Wistar’s BTT and BRT programs with critical hands-on skills as well as the analytical thinking needed to carry out the right experiments for a research project — knowledge he could only gain through on-the-job experience.

“Every aspect of the apprenticeship program was meaningful to me and applies to the work I’m now doing in the COVID-19 space,” said Kwasi. “But most useful is the intense knowledge I gained from having my own project. This challenged me to be more disciplined: I learned how to follow a plan, respect the schedule I set to carry out the research and leave no stone unturned.”

Wistar’s education and training programs, deeply rooted in the Institute’s mission to train the next generation of scientists, are two workforce development models that successfully create cross-boundary collaborations between industry, academia and research institutes, offer in-depth training and education while providing students a wage, and give trainees the skillsets sought after by the life sciences industry.

Wistar’s broad and deep connections to scientists in academia, biotech, government, and pharma, both regionally and nationally, continue to drive opportunities to train scientists at every level and from all backgrounds.

Dr. Maureen Murphy, Ira Brind Professor and program leader of the Molecular & Cellular Oncogenesis Program of The Wistar Institute Cancer Center, has been investigating the importance of inherited mutations in the gene encoding p53 tumor suppressor protein to determine cancer susceptibility in people of African descent and people of Ashkenazi Jewish descent, for the past twenty-two years.

Dr. Murphy published her most recent scientific findings in the journal Cancer Research, together with her research collaborators from more than eleven research hospitals throughout the country, including the University of Pennsylvania and Children’s Hospital of Philadelphia.

The p53 protein is one of the body’s best defenses against cancer and is necessary for response to chemotherapy, overseeing the cell’s fate after assaults that cause DNA damage and other stress stimuli. Controlling several different cellular responses, just like the director of an orchestra keeps all the instrument sections and their musical notes synchronized, p53 decides if cell damage can be repaired or calls for the extreme solution — eliminating the affected cells to prevent malignant transformation. It is through the fundamentally important scientific studies connecting basic science with clinical care, such as Dr. Murphy’s latest publication, that the world is becoming better positioned to implement targeted personalized medicine approaches to improve health care.

Dr. Murphy describes p53 as the most important protein in our body. She explained the significance of the new study and how it came to be in this Q&A.

Q: Since p53 is so important, what happens when it doesn’t work?

A: Mutations in the p53 gene that are acquired during one’s life can compromise the protein’s function and its ability to restrain cancer development. Indeed, p53 is the most mutated gene in cancer. People who are born with inherited p53 mutations have a 90 percent chance of developing cancer in their lifetime, including soft tissue and bone sarcomas, breast cancer and leukemia, a rare condition called Li-Fraumeni Syndrome (LFS). Often, these tumors arise during childhood or early in life, and individuals have multiple tumors throughout their lifetime. These families frequently describe their experience as being “stalked by cancer”.

Q: How important is it for these individuals to know their genetic background?

A: Diagnosis of LFS is critical to help affected families understand their risk and seek appropriate screening for early cancer detection. In these cases, cancer screening is extremely aggressive. Unfortunately, there are many different p53 mutations that correspond to a wide variety of cancer types and risk levels, and we do not yet know if all mutations require the same level of screening. Therefore, it’s very important to identify those mutations and understand what they mean for patients in terms of cancer risk and age of onset.

Q: What did you discover in this new study?

A: Studying eight different families, we identified a rare, lower-risk p53 mutation that is associated with LFS cancer types, but at slightly lower rates and with significantly later age of onset of pediatric cancers. This mutation causes a milder defect in p53 function than other LFS p53 mutations — something we call ‘hypomorphic mutations,’ which result in reduced expression or functional performance of a protein, but not a complete loss. Hypomorphic mutations are rare and typically tend to recur within one ethnicity. We refer to these as ‘founder’ mutations because one or more ancestors in the affected population were carriers of the altered gene and passed it down to their descendants. This specific mutation tracks within the Ashkenazi Jewish population.

Q: How did you start this collaboration with so many other institutions to study this p53 mutation?

A: I gave a seminar at Penn and Dr. Maxwell was in the audience. A few days later, she wrote to me saying she had interesting cancer cases in her clinic and we decided to work together to figure out whether there was a new hypomorphic mutation behind those cases. Science at its best is when we are able to join forces and combine our questions and expertise to solve a biological puzzle and ultimately advance patient treatment.

Q: What pieces of the p53 puzzle are still missing?

A: We need to continue these types of studies to better understand the p53 genetic landscape across populations and the implications of each mutation. I believe that will inform better clinical management of patients and, importantly, help find new specific therapies. We know that people who carry these hypomorphic mutations respond poorly to standard cancer therapy. At the same time, their genetic differences might result in specific vulnerabilities of their tumors. The focus and passion of my lab is to look for these therapeutic vulnerabilities and exploit them to find drugs that can do better for these patients so that we can ultimately tailor therapy to their specific genetic background. We think that a personalized medicine approach, based upon the genetics of the individual and the tumor, is the next frontier for cancer research, and we aim to be at the cutting edge of this frontier.