Week in BioE (May 31, 2019)

by Sophie Burkholder

Vector Flow Imaging Helps Visualize Blood Flow in Pediatric Hearts

A group of biomedical engineers at the University of Arkansas used a new ultrasound-based imaging technique called vector flow imaging to help improve the diagnosis of congenital heart disease in pediatric patients. The study, led by associate professor of biomedical engineering Morten Jensen, Ph.D., collaborated with cardiologists at the local Children’s Hospital in Little Rock to produce images of the heart in infants to help potentially diagnose congenital heart defects. Though the use of vector flow imaging has yet to be developed for adult patients, this type of imaging could possibly provide more detail about the direction of blood flow through the heart than traditional techniques like echocardiography do. In the future, the use of both techniques could provide information about both the causes and larger effects of heart defects in patients.

Using Stem Cells to Improve Fertility in Leukemia Survivors

One of the more common side effects of leukemia treatment in female patients is infertility, but researchers at the University of Michigan want to change that. Led by associate professor of biomedical engineering Ariella Shikanov, Ph.D., researchers in her lab found ways of increasing ovarian follicle productivity in mice, which directly relates to the development of mature eggs. The project involves the use of adipose-derived stem cells, that can be found in human fat tissue, to surround the follicles in an ovary-like, three-dimensional scaffold.  Because the radiation treatments for leukemia and some other cancers are harmful to follicles, increasing their survival rate with this stem cell method could reduce the rate of infertility in patients undergoing these treatments. Furthermore, this new approach is innovative in its use of a three-dimensional scaffold as opposed to a two-dimensional one, as it stimulates follicle growth in all directions and thus helps to increase the follicle survival rate.

Penn Engineers Look at How Stretching & Alignment of Collagen Fibers Help Cancer Cells Spread

Cancer has such a massive impact on people’s lives that it might be easy to forget that the disease originates at the cellular level. To spread and cause significant damage, individual cancer cells must navigate the fibrous extracellular environment that cells live in, an environment that Penn Engineer Vivek Shenoy has been investigating for years.

Shenoy is the Eduardo D. Glandt President’s Distinguished Professor with appointments in Materials Science and Engineering, Mechanical Engineering and Applied Mechanics, and Bioengineering. He is also the Director of the Center for Engineering MechanoBiology (CEMB), one of the NSF’s twelve Science and Technology Centers.

Shenoy’s most recent study on cancer’s mechanical environment was led by a postdoctoral researcher in his lab, Ehsan Ban. Paul Janmey, professor in Physiology and Bioengineering, and colleagues at Stanford University also contributed to the study. Shenoy also received the Heilmeier Award this March and delivered the Heilmeier Award Lecture in April.

Read the rest of this story on Penn Engineering’s Medium Blog.

Controlled Electrical Stimulation Can Prevent Joint Replacement Infections

Joint replacements are one of the most common kinds of surgery today, but they still require intense post-operative therapy and have a risk of infection from the replacement implant. These infections are usually due to the inflammatory response that the body has to any foreign object, and can become serious and life-threatening if left untreated. Researchers at the University of Buffalo Jacobs School of Medicine and Biomedical Sciences hope to offer a solution to preventing infections through the use of controlled electrical stimulation. Led by Mark Ehrensberger, Ph.D., Kenneth A. Krackow, M.D., and Anthony A. Campagnari, Ph.D., the treatment system uses the electrical signal to create an antibacterial environment at the interface of the body and the implant. While the signal does not prevent infections completely, these antibacterial properties will prevent infections from worsening to a more serious level. Patented as the Biofilm Disruption Device TM, the final product uses two electrode skin patches and a minimally invasive probe that delivers the electrical signal directly to the joint-body interface. The researchers behind the design hope that it can help create a more standard way of effectively treating joint replacement infections.

People and Places

TBx: Gabriel Koo, Ethan Zhao, Daphne Cheung, and Shelly Teng

For their senior design project, four bioengineering seniors Gabriel Koo, Ethan Zhao, Daphne Cheung, and Shelly Teng created a low-cost tuberculosis diagnostic that they called TBx. Using their knowledge of the photoacoustic effect of certain dyes, the platform the group created can detect the presence of lipoarabinomannan in patient urine. The four seniors presented TBx at the Rice360 Design Competition in Houston, Texas this spring, which annually features student-designed low-cost global health technologies.

BE Grace Hopper Lecture: Powering Tumor Cell Migration Through Hetergeneous Microenvironments

We hope you will join us for the 2019 Bioengineering Grace Hopper lecture by Dr. Cynthia Reinhart-King.

Date: Thursday, April 4, 2019
Time: 3:30-4:30 PM
Location: Glandt Forum, Singh Center, 3205 Walnut Street

Dr. Cynthia Reinhart-King, Engineering, BME, Photo by Joe Howell

Speaker: Cynthia Reinhart-King, Ph.D.
Cornelius Vanderbilt Professor of Engineering, Director of Graduate Studies, Biomedical Engienering
Vanderbilt University

Title: “Powering Tumor Cell Migration Through Heterogeneous Microenvironments”

To move through tissues, cancer cells must navigate a complex, heterogeneous network of fibers in the extracellular matrix. This network of fibers also provides chemical, structural and mechanical cues to the resident cells. In this talk, I will describe my lab’s efforts to understand the forces driving cell movements in the tumor microenvironment. Combining tissue engineering approaches, mouse models, and patient samples, we create and validate in vitro systems to understand how cells navigate the tumor stroma environment. Microfabrication and native biomaterials are used to build mimics of the paths created and taken by cells during metastasis. Using these platforms, we have described a role for a balance between cellular energetics, cell and matrix stiffness, and confinement in determining migration behavior. Moreover, we have extended this work into investigating the role of the mechanical microenvironment in tumor angiogenesis to show that mechanics guides vessel growth and integrity. I will discuss the mechanical influences at play during tumor progression and the underlying biological mechanisms driving angiogenesis and metastatic cell migration as a function of the ECM with an eye towards potential therapeutic avenues.

Cynthia Reinhart-King is the Cornelius Vanderbilt Professor of Engineering and the Director of Graduate Studies in Biomedical Engineering at Vanderbilt University.  Prior to joining the Vanderbilt faculty in 2017, she was on the faculty of Cornell University where she received tenure in the Department of Biomedical Engineering. She obtained undergraduate degrees in chemical engineering and biology at MIT and her PhD at the University of Pennsylvania in the Department of Bioengineering as a Whitaker Fellow working with Daniel Hammer. She then completed postdoctoral training as an Individual NIH NRSA postdoctoral fellow at the University of Rochester.  Her lab’s research interests are in the areas of cell mechanics and cell migration specifically in the context of cancer and atherosclerosis. Her lab has received funding from the American Heart Association, the National Institutes of Health, the National Science Foundation and the American Federation of Aging Research.  She has been awarded the Rita Schaffer Young Investigator Award in 2010 and the Mid-Career Award in 2018 from the Biomedical Engineering Society, an NSF CAREER Award, the 2010 Sonny Yau ‘72 Excellence in Teaching Award, a Cook Award for “contributions towards improving the climate for women at Cornell,” and the Zellman Warhaft Commitment to Diversity Award from the Cornell College of Engineering. She is a fellow of the Biomedical Engineering Society and the American Institute for Medical and Biological Engineering, and she is a New Voices Fellow of the National Academies of Science, Engineering and Medicine. She is currently a standing member of the NIH CMT study section panel and Secretary of the Biomedical Engineering Society.

Information on the Grace Hopper Lecture:
In support of its educational mission of promoting the role of all engineers in society, the School of Engineering and Applied Science presents the Grace Hopper Lecture Series. This series is intended to serve the dual purpose of recognizing successful women in engineering and of inspiring students to achieve at the highest level.
Rear Admiral Grace Hopper was a mathematician, computer scientist, systems designer and the inventor of the compiler. Her outstanding contributions to computer science benefited academia, industry and the military. In 1928 she graduated from Vassar College with a B.A. in mathematics and physics and joined the Vassar faculty. While an instructor, she continued her studies in mathematics at Yale University where she earned an M.A. in 1930 and a Ph.D. in 1934. Grace Hopper is known worldwide for her work with the first large-scale digital computer, the Navy’s Mark I. In 1949 she joined Philadelphia’s Eckert-Mauchly, founded by the builders of ENIAC, which was building UNIVAC I. Her work on compilers and on making machines understand ordinary language instructions lead ultimately to the development of the business language, COBOL. Grace Hopper served on the faculty of the Moore School for 15 years, and in 1974 received an honorary degree from the University. In support of the accomplishments of women in engineering, each department within the School invites a prominent speaker to campus for a one or two-day visit that incorporates a public lecture, various mini-talks and opportunities to interact with undergraduate and graduate students and faculty. The lecture is open to everyone!

Week in BioE (March 15, 2019)

by Sophie Burkholder

Synthetic Spinal Discs from a Penn Research Team Might Be the Solution to Chronic Back Pain

Spinal discs, the concentric circles of collagen fiber found between each vertebra of the spine, can be the source of immense back pain when ruptured. Especially for truck and bus drivers, veterans, and cigarette smokers, there is an increased risk in spinal disc rupture due to overuse or deterioration over time. But these patients aren’t alone. In fact, spinal discs erode over time for almost everyone, and are one of the sources of back pain in older patients, especially when the discs erode so much that they allow direct bone-to-bone contact between two or more vertebrae.

Robert Mauck, Ph.D.

Robert Mauck, Ph.D., who is the director of the McKay Orthopaedic Research Laboratory here at Penn and a member of the Bioengineering Graduate Group Faculty, led a research team in creating artificial spinal discs, with an outer layer made from biodegradable polymer and an inner layer made with a sugar-like gel. Their findings appear in Science Translational Medicine. These synthetic discs are also seeded with stem cells that produce collagen over time, meant to replace the polymer as it degrades in vivo over time. Though Mauck and his time are still far from human clinical trials for the discs, they’ve shown some success in goat models so far. If successful, these biodegradable discs could lead to a solution for back pain that integrates itself into the human body over time, potentially eliminating the need of multiple invasive procedures that current solutions require. Mauck’s work was recently featured in Philly.com.

An Untethered, Light-Activated Electrode for Innovations in Neurostimulation

Neurostimulation, a process by which nervous system activity can be purposefully modulated, is a common treatment for patients with some form of paralysis or neurological disorders like Parkinson’s disease. This procedure is typically invasive, and because of the brain’s extreme sensitivity, even the slightest involuntary movement of the cables, electrodes, and other components involved can lead to further brain damage through inflammation and scarring. In an effort to solve this common problem, researchers from the B.I.O.N.I.C. Lab run by Takashi D.Y. Kozai, Ph. D., at the University of Pittsburgh replaced long cables with long wavelength light and a formerly tethered electrode with a smaller, untethered one.

The research team, which includes Pitt senior bioengineering and computer engineering student Kaylene Stocking, centered the device on the principle of the photoelectric effect – a concept first described in a publication by Einstein as the local change in electric potential for an object when hit with a photon. Their design, which includes a 7-8 micron diameter carbon fiber implant, is now patent pending, and Kozai hopes that it will lead to safer and more precise advancements in neurostimulation for patients in the future.

A New Microfluidic Chip Can Detect Cancer in a Drop of Blood

Many forms of cancer cannot be detected until the disease has progressed past the point of optimum treatment time, increasing the risk for patients who receive late diagnoses of these kinds of cancer. But what if the diagnostic process could be simplified and made more efficient so that even a single drop of blood could be enough input to detect the presence of cancer in a patient? Yong Zeng, Ph.D., and his team of researchers at the University of Kansas in Lawrence sought to answer that question.

They designed a self-assembled 3D-nanopatterned microfluidic chip to increase typical microfluidic chip sensitivity so that it can now detect lower levels of tumor-associated exosomes in patient blood plasma. This is in large part due to the nanopatterns in the structure of the chip, which promote mass transfer and increase surface area, which in turn promotes surface-particle interactions in the device. The team applied the device to their studies of ovarian cancer, one of the notoriously more difficult kinds of cancer to detect early on in patients.

A Wearable Respiration Monitor Made from Shrinky Dinks

Michelle Khine, Ph. D., a professor of biomedical engineering at the University of California, Irvine incorporates Shrinky Dinks into her research. After using them once before in a medical device involving microfluidics, her lab recently worked to incorporate them into a wearable respiration monitor – a device that would be useful for patients with asthma, cystic fibrosis, and other chronic pulmonary diseases. The device has the capability to track the rate and volume of its user’s respiration based on measurements of the strain at the locations where the device makes contact with the user’s abdomen.

Paired with Bluetooth technology, this sensor can feed live readings to a smartphone app, giving constant updates to users and doctors, as opposed to the typical pulmonary function test, which only provides information from the time at which the test takes a reading. Though Khine and her team have only tested the device on healthy patients so far, they look forward to testing with patients who have pulmonary disorders, in hopes that the device will provide more comprehensive and accessible data on their respiration.

People and Places

Ashley Kimbel, a high school senior from Grissom High School in Huntsville, Alabama, designed a lightweight prosthetic leg for local Marine, Kendall Bane, after an attack in Afghanistan led him to amputate one of his legs below the knee. Bane, who likes to keep as active as possible, said the new lighter design is more ideal for activities like hiking and mountain biking, especially as any added weight makes balance during these activities more difficult. Kimbel used a CAD-modeling software produced by Siemens called Solid Edge, which the company hopes to continue improving in accessibility so that more students can start projects like Kimbel’s.

This week, we would like to congratulate Angela Belcher, Ph.D., on being named the new head of the Department of Biological Engineering at the Massachusetts Institute of Technology (MIT). With her appointment to this role, now half of the MIT engineering department heads are women. Belcher’s research is in the overlap of materials science and biological engineering, with a particular focus on creating nanostructures based on the evolution of ancient organisms for applications in medical diagnostics, batteries, solar cells, and more.

We would also like to congratulate Eva Dyer, Ph.D., and Chethan Pandarinath, Ph.D., both of whom are faculty members at the Walter H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, on receiving research fellowships from the Alfred P. Sloan Foundation. Dr. Dyer, who formerly worked with Penn bioengineering faculty member Dr. Konrad Kording while he was at Northwestern University, leads research in the field of using data analysis methods to quantify neuroanatomy. Dr. Pandarinth leads the Emory and Georgia Tech Systems Neural Engineering Lab, where he works with a team of researchers to use properties of artificial intelligence and machine learning to better understand large neural networks in the brain.



Week in BioE (February 21, 2019)

by Sophie Burkholder

Detecting Infectious Diseases with Paper-Based Devices

Dr. Linnes’ paper device. Image used courtesy of Erin Easterling, Purdue College of Engineering.

Despite great advancements in diagnostics technology over the past few decades, patient accessibility to these technologies remains one of the biggest challenges of the field today. Particularly in low-resource areas, even simple processes can end up taking weeks or months to return results from tests that are normally completed in days. But what if these tests could be simplified to smaller, at-home tests based on properties of microfluidics – something like a pregnancy test but for infectious diseases like HIV?

Jacqueline Linnes, Ph.D., and her team of researchers at Purdue University are working towards finding a way to do just that by creating paper-based devices that use microfluidics to help carry out the necessary diagnostic tests. Specifically, her lab designed such a paper-based system that can detect HIV nucleic acids within 90 minutes of receiving a drop of patient blood. The success of this design shows promise for producing devices for diseases whose diagnostics process involve similar pathways of pathogen detection, opening the door to more applications of at-home tests based in the properties of paper microfluidics.

Here at Penn, undergraduate bioengineering students enrolled in the two-semester laboratory course Bioengineering Modeling, Analysis, and Design (BE 309 & BE 310) have the chance to create their own models of paper microfluidics delivery systems based on given time constraints in a multi-step process. Though the students’ challenge only involves water as a substrate, Linnes’ research demonstrates the later implications of studying fluid flow through a medium as cheap and accessible as paper.

Watch the video below demonstrating Dr. Linnes’ device:

Funding for Cancer Research in Tumor Mimicry and Imaging

Two of the deadliest forms of cancer today are breast cancer and pancreatic cancer, with the latter having a five-year survival rate of only about 8%. Because cancer treatments are often adjusted according to a unique patient-to-patient basis, learning how to improve predictions of tumor behavior could help determine proper therapies sooner.

Chien-Chi Lin, Ph.D., an associate professor of biomedical engineering at Indiana University – Purdue University Indianapolis, recently received a grant from the National Institute of Health to advance his research in pancreatic cancer treatment. His project under the grant involves the development of bio-inspired, responsive, and viscoelastic (BRAVE) cell-laden hydrogels to help understand cell interactions in pancreatic ductal adenocarcinoma, which is the most common form of malignancy in the pancreas. These hydrogels mimic tumor tissue, as well as model tumor development over time, helping to eventually find better ways of treating pancreatic cancer.

In other news surrounding cancer-related research, a team of researchers led by Kenneth Tichauer, Ph.D., at the Illinois Institute of Technology won the university’s Nayar Prize for their development of the Agent-Dependent Early Photon Tomography (ADEPT) Cancer Imager, a machine designed to find early tumor development in the lymph nodes of breast cancer patients. Through the use of a special dyeing process that now dyes the entire lymph node, providing a sharper image that allows for a quicker discovery of smaller tumors.

Penn’s Women in Computer Science (WiCS) Hosts FemmeHacks

Penn President Amy Gutmann and Penn Engineering Dean Vijay Kumar stopped by FemmeHacks at the Pennovation Center Feb. 9. The annual event is a beginner-friendly collegiate hackathon for women-identifying people with an interest in computer programming, and featured a day of all-levels workshops Feb. 8. The event is sponsored by Penn’s Women in Computer Science student organization.

Though the event is not specifically tailored towards applications in bioengineering, skills relating to coding and software development are increasingly important for those interested in pursuing a career in medical device design. In fact, in the evaluation of new medical devices, the FDA often focuses more on software over hardware, as the former is associated with more security liabilities, due to its relative novelty.

Read the full story and see pictures on FemmeHacks on Penn Today.

People & Places

In December, the department of biomedical engineering at the University of Alabama at Birmingham received the Ruth L. Kirschstein National Research Service Awards Institutional Research Training Grant, which will support predoctoral students enrolled in the university’s biomedical engineering graduate programs. The department plans to use the grant for research in cardiovascular tissue engineering.

Case Western Reserve University and Cleveland Clinic announced the launch of an alliance last year with the goal of creating better synergy across the two renowned institutions, hoping to provide more opportunities for students with interest in medicine at all levels, from high school to postdoctoral education. Though researchers from both institutions frequently partner on projects, this new alliance will create a more structured platform for future collaborations.

We would like to commend Steven George, M.D./Ph.D., on his new position as the chair of the Department of Biomedical Engineering at the University of California at Davis. His research involves the development of “organ-on-a-chip” technologies using stem cells and microfluidics to mimic human organ functions of vascularized cardiac, tumor, and pancreatic tissues.

Finally, we want to congratulate Paul Yock, M.D., on his being chosen to receive the National Academy of Engineering’s 2019 Fritz J. and Dolores H. Russ Prize. The prize honors two of Dr. Yock’s inventions from his research in interventional cardiology, one of which is Rapid Exchange, which is a kind of stenting and balloon angioplasty system. Dr. Yock is the Martha Meier Weiland Professor in the School of Medicine and Professor of Bioengineering.



Week in BioE (July 25, 2018)

Advances in Stem Cell Research

Stem cell therapy has been used to treat a variety of conditions.

A paper published this month in Scientific Reports announced a new a strategy for the treatment of segmental bone defects. The new technique, called Segmental Additive Tissue Engineering (or SATE) comes from a team of researchers with the New York Stem Cell Foundation Research Institute (NYSCF). A press release from the NYSCF and an accompanying short video (below) describe the breakthrough technique, which will “[allow] researchers to combine segments of bone engineered from stem cells to create large scale, personalized grafts that will enhance treatment for those suffering from bone disease or injury through regenerative medicine.”

Segmental Additive Tissue Engineering from NYSCF on Vimeo.

Ralph Lauren Senior Investigator Guiseppe Maria de Peppo, PhD, and first author Martina Sladkova, PhD, express their hope that this new procedure will help address some of the limitations of bone grafts, such as immune system rejection, the need for growing bones in pediatric patients, and the difficulty of creating larger bone grafts made from patient stem cells.

Elsewhere in stem cell research, the Spanish Agency for Medicines and Medical Devices has given the company Viscofan BioEngineering approval to start clinical trials for stem cell therapy to treat heart failure. Already a world leader in the market for medical collagen, Viscofan is now turning its research toward using collagen (a protein found in the connective tissue of mammals) to strengthen the weakened heart muscle of those with ischemic cardiomyopathy, a type of heart failure and the leading cause of death in the world. This new “Cardiomesh” project includes collaborators from industry, academia, and hospitals to create this elastic and biodegradable product. Viscofan expects to start clinical trials after the summer of this year, and the full details can be found in Viscofan’s press release.

Federal Grant Supports International Bioengineering Research

The Canadian government awarded a $1.65 million federal grant to two top Canadian universities to develop a center based on engineering RNA. The University of Lethbridge and the Université de Sherbrooke will team up with international collaborators from the United States, Germany, France, Australia, and more and to found and develop the Ribonucleic Acid Bioengineering and Innovation Network Collaborative Research and Training Experience over the next six years. This comes as part of the Canadian government’s CREATE initiative, which awards grants to research teams across the country to support research, innovation, and jobs-creation in the sciences. These two universities are national leaders in the field of RNA research, a diverse and interdisciplinary field. This new network will focus on training of both young academics transitioning to industry and entrepreneurs looking to develop new technologies. This project is led by Hans-Joachim Wieden, PhD, Chemistry and Biochemistry faculty at the University of Lethbridge and an Alberta Innovates Strategic Chair in RNA Bioengineering.

Lehigh University Awarded Grant in Ebola Research

Close to Philadelphia in Allentown, PA, researchers at Lehigh University received a National Science Foundation (NSF) grant to support their research into one of the deadliest of modern diseases, the Ebola virus, which is highly infectious and currently without vaccine or cure. Entitled “TIM Protein-Mediated Ebola Virus-Host Cell Adhesion: Experiments and Models,” the goal of this research is to create a “predictive and quantitative model of the Ebola Virus (EBOV)-host cell interactions at the molecular through single-virus levels.” Building on past research, the investigators ultimately hope to provide the first quantitative study of this type of cell interaction. By studying how EBOV enters the body through healthy cells, the aim is to understand how it works and ultimately develop a technique to stop its entry. The lead investigator, Anand Jagota, PhD, is the current Professor and Founding Chair of Lehigh University’s Bioengineering program.

New Research in Brain Tumor Removal

The National Institute of Biomedical Imaging and Bioengineering (NIBIB) awarded a grant to Fake (Frank) Lu, PhD, Assistant Professor of Biomedical Engineering at the State University of New York (SUNY) at Binghamton in support of his research to design more accurate techniques for the removal of brain tumors. His technique, called Stimulated Raman Scattering or SRS, is a mode of identifying molecules during surgery which can be used to create a highly detailed and accurate image. Dr. Lu’s SRS techniques will improve both the speed of the surgery and the accuracy of the tissue removal. With this grant support, Dr. Lu’s team will collaborate with local universities and hospitals on collecting more data as their next step before making the technology more widely available.

People and Places

Undergraduate students at our neighbor Drexel University received the Robert Noyce Scholarship, an NSF program that supports students seeking their teacher certification in science and math at the middle school level. The co-investigators and undergraduates are from a variety of disciplines and programs across the university, including co-investigator Donald L. McEachron, PhD, Teaching Professor of Biomedical Engineering, Science and Health Systems. The students’ curriculum in the DragonsTeach Middle Years program will combine rigorous preparation for teaching STEM subjects and the foundational knowledge to work with under-served schools.

Another group of students, this time from California State University, Long Beach, used their victory in the university’s annual Innovation Challenge as an opportunity to launch a startup called Artemus Labs. Their first product, “Python,” uses body heat other physical sensations to regulate a prosthetic liner, useful in making sure prosthetic limbs are comfortable for the wearer. The students explained that their idea was driven by need, as few prosthetic manufacturers prioritize such factors as temperature or sweat regulation in the creation of their products.

Finally, the University of Southern California Viterbi School of Engineering has a new Chair of Biomedical Engineering: Professor K. Kirk Shung, PhD. Dr. Shung obtained his doctorate from the University of Washington and joined USC in 2002. With a background in electrical engineering, Dr. Shung’s research focuses on high frequency ultrasonic imaging and transducer development, and has been supported by a NIH grant as well as won multiple awards from the American Institute of Ultrasound in Medicine and the Institute of Electrical and Electronics Engineers (IEEE), among others.

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 penngabe@gmail.com for an interview by GABE (Graduate Association of Bioengineers) and let us know!

Dan Huh Receives $1M CRI Grant to Study Cancer

CRI huh
Dan Huh, Ph.D.

Dan Huh, Wilf Family Term Assistant Professor in the Penn Department of Bioengineering, has received the Cancer Research Institute (CRI) Technology Impact Award. Dr. Huh, whose research attempts to model cancer-immune cell interactions in microphysiological systems, will receive $1 million over the next three years for direct costs of his research.

“This award will provide us with an exciting opportunity to explore the potential of our organ-on-a-chip technology for the study of cancer immunotherapy, which is one of the most promising yet poorly understood clinical strategies for cancer treatment,” Dr. Huh said. “I am honored to receive this major award and excited with the prospect of contributing to this rapidly emerging area of medicine using innovative bioengineering technologies.”

Join us in congratulating Dr. Huh!