This Week in BioE (June 22, 2017)

Diversifying the Field

One of the ongoing issues in STEM (science, technology, engineering, and medicine) fields is a lack of diversity among students and faculty. Bioengineering stands out among other engineering fields because it enjoys terrific gender diversity. For example, about half of Penn Bioengineers are women, a feature of our class that goes back decades.

diversifyingHowever, diversity extends well beyond gender. For example, the National Research Mentoring Network (NRMN) has been working to increase diversity, including among students with disabilities. A consortium of people and groups providing mentors for science students, the MRMN recently highlighted the American Association for the Advancement of Science’s (AAAS) Entry Point! program, which focuses on helping students with physical disabilities. Mentoring, it turns out is a big part of helping these students succeed.

Another recent development that should help to increase diversity in the field is the awarding of a $1 million grant from the National Science Foundation’s Directorate of Engineering to the University of Wisconsin, Madison, and the College of Menominee Nation (CMN), a native American college in Wisconsin, to collaborate in engineering research and education. The new grant builds on a program begun in 2010 between the colleges to build labs and facilitate the transfer of pre-engineering students from CMN to UWM.

Brain Science Developments

Speaking of education, three recent news stories discuss how we might be able to expedite the learning process, increase intelligence, and reward ourselves when we create art. In one of the stories, a company called Kernel is investing $100 million in research at the University of Southern California to determine whether using brain implants, which have been helpful in some patients with epilepsy, can be used to increase or recover memory. If successful, this may bridge one critical treatment gap in neurology. About one out of every three people with epilepsy don’t respond to drug treatment.

In the second story, scientists at the University of Texas at Dallas were awarded a $5.8 million contract from DARPA to investigate the role of vagus nerve stimulation in accelerated learning of foreign languages. Stimulating the peripheral nervous system to activate and train areas of the brain is one more example that our nervous system is connected in ways that we do not yet understand completely. The Department of Defense hopes to use the technology to more quickly train intelligence operatives and code breakers.

Finally, in a third story involving the brain, a professor at Drexel University used functional near-infrared spectroscopy to determine which parts of the brain were activated while participants were making art. Dr. Girija Kaimal’s team found that creative endeavors activate the brain’s rewards pathway, as well as elevating the participants’ self-opinion. So making art always made people feel good about themselves; now we know more of the reasons why.

Ghana Trip to Study Tuberculosis: Day 29

Ghana 29.1
One of our favorite memories was visiting King Otumfuo Nana Osei Tutu II of the Asante region (left to right: Salim, Jason Grosz, David Pontoriero, Kaila Helm, Hope McMahon, Dr. David Issadore, Danielle Tsougarakis, Ethan Zhao, Kathleen Givan, Dr. Miriam Wattenbarger, Katharine Cocherl, Kate Panzer).

David Issadore, a faculty member in the Department of Bioengineering at the University of Pennsylvania teaches an engineering course ENGR566 – Appropriate Point of Care Diagnostics. As part of this course, he and Miriam Wattenberger from CBE, have taken nine Penn students, most of them majoring in Bioengineering, to Kumasi, Ghana, to study the diagnosis of pediatric tuberculosis. While in Ghana, these students are blogging daily on their experiences.

As we woke up early to prepare for the nine-hour flight ahead of us, we all acknowledged that time really does fly. Arriving at the Accra airport, we had to say goodbye to our Ghanaian friends Salim, Uncle Ebo, and Nana Yaa. The month has come and gone. It feels like the trip went quickly, but we have learned so much and gained many valuable experiences along the way. From our hospital and clinic visits, to our interactions with an herbalist and a fetish priestess, we were exposed to many healthcare settings found in Ghana. We had the opportunity to present our pediatric tuberculosis diagnostic ideas to a room filled with researchers and clinicians, getting invaluable feedback from multiple experts. Along with our academic pursuits, we also got to explore the Ghanaian culture and learn about customs, traditions, food, and much more. We met many friendly people along the way. These aspects are the memories that we will remember for years to come. As we move beyond this course, we are excited to continue pursuing our interests in biomedical diagnostics and problem solving that can be applied globally. We would like to thank everyone who helped make this unforgettable experience possible.

Foundational Engineering Theory in Design and Translation

What a nanoparticle remembers during its journey is pictorially represented in the above figure, and this “memory” is crucial in predicting its approach to the blood vessel wall and its subsequent capture by cell surface receptors, collectively determining the efficacy of therapeutic drug delivery. Reprinted from: Ramakrishnan et al, “Motion of a nano-spheroid in a cylindrical vessel flow: Brownian and hydrodynamic interactions,” J Fluid Mech. 2017;821:117-152, with permission of Cambridge UP, owner of copyright.

A recent article coauthored by Ramakrishnan Natesan, a postdoctoral fellow in the Department of Bioengineering who works in the lab of Dr. Ravi Radhakrishnan, and published in the Journal of Fluid Mechanics provides an elegant and rigorous approach to integrate the memory, errant motion, and adhesion effects in the dynamics of colloidal nanoparticles of different sizes and shapes. The method described in the article computationally analyzes how the hydrodynamic forces are influenced by size, shape, and nature of confining boundary amidst blood flow.

In traditional modes of therapeutic treatment, such as a direct intravenous (IV) injection, only a small fraction of injected drug accesses the diseased tissue. Suboptimal therapeutic delivery represents an acute challenge by limiting the efficacy of biotherapeutics. Strategies to address and overcome this challenge may be based on theoretical and computational approaches to in order to help design innovative, quantitative, experimental methods. Targeted therapeutic delivery using nanoparticles coated with specific targeting molecules is such an approach in therapeutic and diagnostic applications.

Targeted delivery is inherently a multiscale problem: a broad range of length and time scales govern the hydrodynamic, microscopic, and molecular interactions mediating nanoparticle motion in blood flow and capture due to cell binding. The events following upon the injection of a targeted therapeutic nanoparticle bearing a drug (nanocarrier) include flow through blood vessels and maneuvering around much larger entities in the blood, such as the red blood cells. Nanoparticles eventually break free to approach the wall of the blood vessel — a phenomenon collectively known as margination.

After margination, the nanoparticle is relatively free from the influences of the blood cells but starts to “feel” the approach to the wall. It needs to get excruciatingly close to the wall to stick — a phenomenon known as adhesion or capture. In the backdrop of this arduous journey is the inescapable randomness of its motion caused by Brownian forces, an erratic form of motion that only impacts nanoscale objects. The interplay among fluid forces, Brownian fluctuations, and wall interactions shape the detailed itinerary of the nanoparticle.  How it moves at a given location and given time is intricately coupled with the motion of the surrounding fluid, namely the blood plasma, which is mostly water. Together, they decide to pave the path forward in time described by a “memory function.”

“The optimization of future drug delivery agents, such as targeted therapeutic nanocarriers, could be based on our computations,” Dr. Ramakrishnan says. “This will, in effect, establish a rational computational platform for fast tracking the clinical translation from carrier design to clinical practice.”

Ghana Trip to Study Tuberculosis: Day 28

Ghana 28.2
Students enjoy their last dinner in Ghana at Buka, a Ghanaian and Nigerian restaurant in Accra (left to right: Jason Grosz, Ethan Zhao, Danielle Tsougarakis, Hope McMahon, Salim, Uncle Ebo, Kaila Helm, Kate Panzer, Katharine Cocherl, Kathleen Givan).

David Issadore, a faculty member in the Department of Bioengineering at the University of Pennsylvania teaches an engineering course ENGR566 – Appropriate Point of Care Diagnostics. As part of this course, he and Miriam Wattenberger from CBE, have taken nine Penn students, most of them majoring in Bioengineering, to Kumasi, Ghana, to study the diagnosis of pediatric tuberculosis. While in Ghana, these students are blogging daily on their experiences.

Today marked our last full day in Ghana. In the morning, we set off rather early to start our day in Accra. But first, we had to drop one of our students, Dave, at the airport so he could make his way to Rwanda to visit a college friend. As we traveled to the airport, we had the opportunity to get a better picture of what life is like in Ghana’s capital. It was nice to go back to Accra and see how different it was from Kumasi. It is a much larger city, with various government buildings, people walking about, and large advertising signs every few yards.

Ghana 28.1
Kwame Nkrumah stands with past Vice Provost Roy Nichols in front of the Benjamin Franklin statue on College Green.

Our first stop was the Kwame Nkrumah Memorial Park. Kwame Nkrumah was the first president of Ghana when the country gained independence in 1957. Interestingly, he went to Penn to earn a Master of Arts in philosophy and a Master of Science in education. The mausoleum in Accra contains his and his wife’s bodies. It is surrounded by various water fountains, which are a symbol of life to provide a sense of immortality for Nkrumah. Many Ghanaians want to continue the work that Nkrumah did not get to finish by helping Ghana to continue developing as an independent country. In addition, there is a museum that contains many of his clothes and pictures of him as he met with various world leaders. We even saw a picture of him on Penn’s campus, shaking the hand of then Vice Provost Roy Nichols.

After the tour, we met Dr. Ellis from KCCR for lunch at a nice open-air restaurant, called Buka. Many of us stuck to our favorites of chicken and fried plantains, but some ventured out to try guinea fowl and snails. After lunch, we walked around the area to some nearby vendors, where we were able to shop for last minute gifts. We soon realized how much more expensive Accra was, compared to Kumasi.

We headed back to the hotel to relax a bit before dinner. For our last night in Ghana, we went out to a restaurant that had a live jazz band. We had our last taste of Ghanaian cuisine and had fun dancing to highlife music. Highlife is a genre of music that we only recently learned is popular in both Ghana and Nigeria. To end our last night in Ghana, we headed back to the hotel. After spending some time to prepare, we huddled in the hotel’s lobby for our talent show, and as night turned into morning, we reluctantly headed to our rooms to finish packing for our early departure.

Ghana 28.3
The APOC program began and ended in Accra, the capital of Ghana.

Ghana Trip to Study Tuberculosis: Day 27

by Ethan Zhao, Bioengineering ’19; and Jason Grosz, Bioengineering ’19

Ghana 27.1
The APOC team poses in front of the rooms at Coconut Grove, resembling huts on the outside and furnished with beds and a bathroom on the inside (left to right: Salim, Ethan Zhao, Jason Grosz, Dr. Ocek Eke, Dr. Miriam Wattenbarger, Hope McMahon, David Pontoriero, Kaila Helm, Kathleen Givan, Kate Panzer, Danielle Tsougarakis, Katharine Cocherl, Nana Yaa).

David Issadore, a faculty member in the Department of Bioengineering at the University of Pennsylvania teaches an engineering course ENGR566 – Appropriate Point of Care Diagnostics. As part of this course, he and Miriam Wattenberger from CBE, have taken nine Penn students, most of them majoring in Bioengineering, to Kumasi, Ghana, to study the diagnosis of pediatric tuberculosis. While in Ghana, these students are blogging daily on their experiences.

Today was the second day that we spent in the coastal city of Cape Coast. Many of us woke up earlier than usual to walk along the beach and explore the resort. While walking along the beach, we noticed large rowboats in the distance that were anchored to the shore by ropes. We originally thought that they were fishing boats, but it turned out that they were digging up sand from the ocean floor to restore sand erosion on the beach.

Ghana 27.2
Students (left to right) Kate Panzer, Hope McMahon, Katharine Cocherl, and Danielle Tsougarakis stand along the beachfront of Coconut Grove in Cape Coast, with the Atlantic Ocean in the background.

After breakfast, we traveled outside of Cape Coast to Kakum National Park, which is a dense tropical rainforest on the coast that is home to many wildlife species, including monkeys, leopards, elephants, and antelope. It is also the home of one of Africa’s largest canopy walkways, consisting of rope suspension bridges more than one hundred feet above the forest floor. The views from the bridges were amazing, as we could see for miles across the tops of the rainforest trees. While we were on the bridges, it started drizzling, which was refreshing given the heat. After leaving Kakum National Park, we drove back to Accra, the capital of Ghana, where we will stay for the remainder of our trip.

Ghana 27.3
The APOC students stand on a platform among the treetops of Kakum National Park, 100 feet above the ground (left to right: Salim, David Pontoriero, Kathleen Givan, Kate Panzer, Ethan Zhao, Danielle Tsougarakis, Jason Grosz, Hope McMahon, Katharine Cocherl)

Chow Wins NIH Grant for Brain Study

Chow R01
Brian Chow, Ph.D.

The National Institutes of Health (NIH) has awarded a grant to Brian Chow, Ph.D., an assistant professor in the Department of Bioengineering, to study ultrafast genetically encoded voltage indicators (GEVIs). GEVIs are proteins that can detect changes in the electrical output of cells and report those changes by emitting different color light. His research seeks to create GEVIs that can report these changes much more rapidly – in fact, more than a million times more quickly than the velocity of the changes themselves – and apply these ultrafast GEVIs to the study of the brain.

The NIH-funded research will build on earlier research, employing de novo fluorescent proteins (dFPs) created in Dr. Chow’s lab. These dFPs, which are totally artificial and unrelated to natural proteins, report voltage changes in neurons by changing in brightness. Working with a team of investigators that includes faculty members from the Departments of Biochemistry & Biophysics and Neuroscience, Dr. Chow hopes to develop these ultrafast GEVIs.

“Monitoring thousands of neurons in parallel will shed new light on cognition, learning and memory, mood, and the physiological underpinnings of nervous system disorders,” he says.

Ghana Trip to Study Tuberculosis: Day 26

by Dave Pontoriero, Biotechnology MS ’18

Ghana 26.1
A Portuguese church found in the center of the Elmina Slave Castle.

David Issadore, a faculty member in the Department of Bioengineering at the University of Pennsylvania teaches an engineering course ENGR566 – Appropriate Point of Care Diagnostics. As part of this course, he and Miriam Wattenberger from CBE, have taken nine Penn students, most of them majoring in Bioengineering, to Kumasi, Ghana, to study the diagnosis of pediatric tuberculosis. While in Ghana, these students are blogging daily on their experiences.

Today, we said goodbye to our Kumasi friends and left the Ashanti region for the final leg of our trip. After our bonus night in the new student hostel (dormitory), we boarded the KNUST bus for a six-hour road trip to Cape Coast. The drive was pleasant, and the scenery became more coastal as we continued. Most people slept through it, but once the ocean became visible, everyone woke up in excitement because we knew we were getting close to Elmina, a beach town just west of Cape Coast.

As we drove through the town, we noticed that it resembled many of the beach towns back home. Our driver, Uncle Ebo, then parked in front of an enormous white castle. It was located on the edge of a peninsula, with a narrow beach to its left and crashing waves to its right. It had cannons situated all along its upper levels and a bustling group of locals hanging out in front of its entrance. It was the Elmina Slave Castle, also known as St. George’s Castle, and the team started to prepare for the tour.

Ghana 26.2
Cannons are found on the perimeter of the Elmina Slave Castle, which point out toward the Atlantic Ocean.

As we entered the castle, the mood became somber. A tour guide provided us with a background of the building, which was a Dutch fort used over the years to facilitate the sale and transport of people from Ghana and the surrounding countries during the slave trade. The first portion of the tour followed the path of a slave during their internment, beginning with the female quarters, then the courtyards used for public punishment, the male quarters, punishment cells, and lastly the final exit where people were loaded onto the ships for their journey across the Atlantic. It was a grim tour to take, and the guide shared some incredibly harrowing stories throughout. The second portion of the tour focused more on other aspects of the fort.

Once we loaded back onto the bus, the team reflected on the experience we had at Elmina Castle as we drove away. After a half-hour drive, we soon arrived to our new rooms at a local beachfront resort called Coconut Grove. Its beautiful facility included a private beach, an ocean-facing restaurant/bar, beachfront swings, a golf course, horse stables, and a crocodile pond (with ~10 real crocodiles!). We went out to a local restaurant with live music, danced a bit, then headed home to enjoy the amenities during one of our last nights together as a team.

Ghana 26.3
The breathtaking view of Elmina, a beach town on the coast of Ghana near Cape Coast.

Ghana Trip to Study Tuberculosis: Day 25

by Danielle Tsougarakis, Bioengineering ’20; and Kate Panzer, Bioengineering ’18

Ghana 25.1
Our last trip to Icy Cup, a yogurt food truck and shop chain that can be found scattered across campus and in other major commercial areas in Kumasi (left to right: Hope McMahon, David Pontoriero, Ethan Zhao, Martin, Katharine Cocherl, Kate Panzer, Kaila Helm).

David Issadore, a faculty member in the Department of Bioengineering at the University of Pennsylvania teaches an engineering course ENGR566 – Appropriate Point of Care Diagnostics. As part of this course, he and Miriam Wattenberger from CBE, have taken nine Penn students, most of them majoring in Bioengineering, to Kumasi, Ghana, to study the diagnosis of pediatric tuberculosis. While in Ghana, these students are blogging daily on their experiences.

This morning, we found out that we would be spending our last night in Kumasi in a hostel, which is equivalent to a dormitory at a U.S. college. We packed our belongings and moved into a hostel called “Complex Brunei,” which is an apartment-style dorm for upperclassmen, each room furnished with three beds, a closet, a full bathroom, and a table. We were all excited to get the student experience of staying in a hostel and compare it to the visitor housing at the KCCR guesthouse.

In the afternoon, we had the opportunity to visit the international community school (ICS),  a high school founded on the philosophy of bringing competitive, Western-inspired education to Kumasi. A friend of our team member Dave currently works at ICS and suggested we come speak to the prospective college students at the school. That being said, we gave a presentation on how the college application process works in the United States to a group of 10th and 12th graders. After our brief overview, we split into small groups and answered individual questions students had regarding different types of universities, SAT/ACT scores, the importance of a strong essay, and other application essentials. Speaking with the prospective students here and motivating them to apply to American universities was a great experience. Sharing our own college application processes and stories with the students was a fun and engaging way to fuel their academic aspirations. After our well-received presentation, the whole team left feeling accomplished.

Ghana 25.2
For our last night in Kumasi, we spent quality bonding time with our new friends Seun (Pittsburgh) and Tim (Michigan) and said our goodbyes.

For dinner, we had a special surprise outing to a nearby Chinese restaurant, where we shared many different dishes and passed them around on a rotating glass platform. For some of the Ghanaians, this was their first time trying Chinese food, so it was fun to hear their reviews of all the dishes. Upon returning to campus, we continued our beloved tradition of team bonding by playing the Noun Game and card games.

Ghana Trip to Study Tuberculosis: Day 24

by Kaila Helm, Biological Basis of Behavior ’20;  Kathleen Givan, Bioengineering and Political Science ’20; Katharine Cocherl, Bioengineering ’20; and Hope McMahon, Chemical and Biomolecular Engineering ’18

Ghana 24.1
At a nearby hostel (dormitory), the APOC students gather to watch a big football match between the Ghanaian and the Ethiopian national teams. (Ghana won!)

David Issadore, a faculty member in the Department of Bioengineering at the University of Pennsylvania teaches an engineering course ENGR566 – Appropriate Point of Care Diagnostics. As part of this course, he and Miriam Wattenberger from CBE, have taken nine Penn students, most of them majoring in Bioengineering, to Kumasi, Ghana, to study the diagnosis of pediatric tuberculosis. While in Ghana, these students are blogging daily on their experiences.

We started our not-so-lazy Sunday with a late start. We enjoyed our last weekend breakfast, provided by the one and only Nana Yaa. A fan favorite is always the avocados and the Milo, which we know we will miss dearly when we get back to the States. Luckily, we all have our personal stashes we plan on bringing back. We all had the much-needed opportunity to do laundry and catch up on life errands. Once mid-afternoon hit, we all decompressed by watching the Ghanaian vs. Ethiopian National Football teams on the television in a nearby dorm. GHANA WON THE FIFA QUALIFIER AND THE CROWD WENT WILD!!!!!

Ghana 24.2
The APOC girls show off their newly made Ghanaian clothing at the Closing Ceremony (left to right: Katharine Cocherl, Kathleen Givan, Kate Panzer, Kaila Helm, Danielle Tsougarakis, Hope McMahon)

The next thing on the agenda was our farewell ceremony and dinner. We were instructed to wear our Ghanaian clothing that had been made for us during the trip, but some of us had not yet received the alterations back from the seamstress. When Nana arrived, clothes in hand, it was exhilarating to see the final products and wear similar colorfully patterned clothes to our Ghanaian counterparts.

The meal was catered by our favorite kebab stand, along with drinks, tilapia, and banku (the classic combination). Many of the people who have contributed immensely to our trip were there, and we enjoyed good conversation and memories into the night. We were put to shame as we watched the children dance their hearts out, using more rhythm and soul than we would know what to do with. It was so nice to see the program come full circle. We all looked back fondly at the welcome ceremony, where all the faces were unfamiliar but kind. Fast forward to the farewell ceremony, and this time, we saw the same faces and smiles, but now we felt connected to the people behind them.

Researchers Visualize Resistant Cancer Cells

by Meagan Ita, Ph.D. Student in Bioengineering and GABE Co-President

Cancer is a disease that affects millions, and over the last several decades, researchers have delved deeply into the biological underpinnings of the disease in the hopes of finding a cure. One major discovery is that mistakes in your DNA “instructions” can lead to cancer by crossing the wires in your cellular circuitry, and researchers have developed amazing new drugs that can cause tumors to melt away by targeting these broken components. The problem though is that, most of the time, the tumors come back, and this is a huge barrier to cures.

Shaffer ASCO
Picture of patient treated with vemurafenib and then developing resistance. Courtesy of the American Society of Clinical Oncology

For a long time, everyone assumed that the reason the tumors came back was  DNA mistakes on top of the original mistakes, with these new mistakes blocking the activity of the anti-cancer drug. However, new work led by Sydney Shaffer from the Arjun Raj Lab at Penn Bioengineering, published this week in Nature, challenges this view by looking all the way down at individual cancer cells and seeing how they respond to these drugs on a cell-by-cell basis.

Sydney found that in melanoma, contrary to what researchers thought, it need not be a DNA mistake that leads a cell to become resistant to the drug, but rather a change in cellular identity. Just like your body has cells of all different types, like skin cells and brain cells, cancer cells appear to change between different types, but unlike in the body, cancer cells do it in a seemingly random and uncontrolled way, and the cells exploit this variability to allow those rare cells that have changed their type to survive the drug.

Here, we talk with Sydney about the inspiration, triumphs, and challenges she faced in her research.

What was the initial inspiration for looking at drug resistance in melanoma?

For the first two years of working on this project, we actually didn’t have a clear question in mind. I was just trying a bunch of different experiments with melanoma cells, and I noticed something that we found thought-provoking. Whenever we gave the melanoma cells a particular drug, they would become resistant at exactly the same point in time. At first, this may not seem unusual, but for example, if everyone showed up at a restaurant to eat lunch at exactly noon, you would guess this was not happening purely by chance. Maybe classes let out right beforehand? Or a big meeting? For the melanoma cells, we would similarly expect there to be a range of different times for the cells to become resistant, but instead it all happened at once.

This observation helped us figure out that the drug-resistant cells probably already exist before we treat them. It also got us curious about the particular processes that make the cells resistant, and we spent many lab meetings discussing this observation until one postdoc, Gautham Nair, suggested trying some experiments based upon the classical molecular biology experiments of Luria and Delbrück.

Who were Luria and Delbrück, and how did they influence your work?

Max Delbrück and Salvador Luria (below) were scientists who, in the 1940s, performed a clever experiment that demonstrated that bacteria become resistant to viruses through random DNA mutations. According to Wikipedia, Luria actually had the idea for these experiments while watching slot machines!

Shaffer D&L
Delbrück (left) and Luria. Courtesy of the Genetics Society of America.

Their experiment was super simple: it was basically a statistical way to see whether cells “sense and respond” to a challenge, or whether they just passively get a mutation that lets some fraction of them survive the challenge, basically like Darwinian evolution. The idea is that, in the first scenario, there is no history: every cell has an equal chance to respond when challenged.

But in the second scenario, history matters in that if your great-grandparent was a survivor, then all your relatives would be too. If you could redo history over and over, then sometimes maybe your great-great-great-great-grandparent would be a survivor, and so you would get a whole bunch of survivors when the challenge came. Luria and Delbrück’s results showed that this second scenario was what happened with bacteria, providing the first evidence for genetic mutations in bacteria occurring in the absence of selection, and they both went on to win a Nobel prize in 1969.

Arjun actually had just lectured about these experiments in our graduate course on modeling biological systems. We adapted the same strategy and theory as Luria and Delbrück’s experiments for our work but applied it to melanoma and actually found a different result. Our experiments showed that resistance in melanoma does not arise through a heritable DNA mutation.

Shaffer colony
Picture of a resistant colony growing in the Raj lab.

Based upon this work, do you have any ideas for how we might prevent resistance in patients?

Yes. The recommended dosing for many of these drugs is daily. Our work would suggest that something like interval therapy might be more effective, for instance, if you gave the drug for a few days, killed many of the tumor cells, and then stopped the drug. During the time that the drug is stopped, the cells that initially survived the drug (we call these cells pre-resistant) could then transition out of this cell state and back to a sensitive state. Then, when the patient takes the drug again, it would be more effective at killing the remaining tumor cells. Another idea would be to find drugs that are specific to the pre-resistant cells and give these drugs in combination with other targeted therapies.

Were there any “Aha!” moments while working on this project?

One of the most exciting moments of this research was when we first found the pre-resistant cells. Hidden among thousands of pictures of empty cells, we were shocked to actually see the rare cells full of brightly tagged resistance genes (below).

Shaffer cells
Resistant cells growing in the Raj lab.

What were some low points in working on the project? Do you recall any specific moments that you just felt intellectually and/or emotionally stumped? How did you get through them?

Oh yes, there were definitely low points during this project. One that stands out to me specifically was this one Friday afternoon where I presented at lab meeting. At the time, I only had a little bit of preliminary data. One of the members of the lab asked me a series of questions about resistance: How many different drug doses had I tried? Could I just give a lot and kill them all? What dose of drug is relevant for patients? What about drug resistance? Was I really interested in? All reasonable questions to ask. However, this was really overwhelming to a first-year graduate student because it made me realize that I didn’t have a clearly defined project that I was working on yet. There were just so many different questions that I didn’t know where to start.

Ultimately, with Arjun’s guidance, I came to realize that this was part of the process of figuring out what my thesis project would be, and the vagueness of our ideas at this time was a great thing because it left me open to find a problem that I found really interesting.

At another point in working on this: I remember that we were clearly conceptually stuck. We had identified the rare cells, but it wasn’t clear how to find out if these were the same cells that become resistant to drug. I had an entire lab meeting where we discussed this concern and came to the conclusion that, without some connection between the cells in this state and resistance, the work would be very speculative, which felt unsatisfying to me. Unfortunately, there wasn’t a quick fix to this problem. We just ended up trying a whole bunch of different ideas and eventually one of our strategies worked out.

Were there any funny moments that stand out to you?

Yeah! I was 40 weeks pregnant as we were finishing off our first submission of the paper! As my due date passed, I was really feeling the pressure to finish everything. Each day, I was coming into lab and just hoping I wouldn’t go into labor yet! Actually, the members of our lab had placed bets on when the baby would be born. Fortunately, those who bet on a late arrival ended up winning, and we submitted the paper the day before my daughter, Julien, was born. I was actually still at the hospital when I got the e-mail that the paper went to review.

So even though it might seem like this project is checked off the list with a kick-ass publication, there are probably a bunch of unfinished ideas you have. So,what are you working on next? Will this project ever be “done?”

For sure. The list of unfinished ideas is very long, and some of the questions that came from this work are now being pursued by other people in the lab. Right now, I’m working on ways of measuring the length of time that individual cells remain in these different cell states.

Interested in sharing your research in Penn BE? Contact for an interview by GABE (Graduate Association of Bioengineers) and let us know!