Tag: cancer

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Understanding the Cellular Mechanisms Driving Solid Tumors’ Robust Defense System

by Nathi Magubane

In a collaborative interdisciplinary study, Michael Mitchell of the School of Engineering and Applied Science, Wei Guo of the School of Arts & Sciences, and Drew Weissman of the Perelman School of Medicine show that solid tumors can block drug-delivery mechanisms with a “forcefield-like” effect but certain genetic elements that can effectively “shut down” the forcefield. Their findings hint at new targets for delivering cancer treatments that use the body’s immune system to fight tumors. (Image: iStock / CIPhotos)

The tumor microenvironment—an ad hoc, messy amalgamation of signaling molecules, immune cells, fibroblasts, blood vessels, and the extracellular matrix—acts like a “powerful security system that protects solid tumors from invaders seeking to destroy them,” says Michael Mitchell, a bioengineer at the University of Pennsylvania working on nanoscale therapeutics aimed at targeting cancers.

“A lot like the Death Star with its surrounding fleet of fighter ships and protective shields, solid tumors can use features like immune cells and vasculature to exert force, acting as a physical barrier to rebel forces (nanoparticles) coming in to deliver the payload that destroys it,” Mitchell says.

Now, researchers in the Mitchell lab have teamed up with Wei Guo’s group in the School of Arts & Sciences at Penn and Drew Weissman of the Perelman School of Medicine to figure out the molecular mechanisms that make tumor microenvironments seemingly impenetrable and found that small extracellular vesicles (sEVs) are secreted by tumor cells and act as a “forcefield,” blocking therapeutics. Their findings are published in Nature Materials.

“This discovery reveals how tumors create a robust defense system, making it challenging for nanoparticle-based therapies to reach and effectively target cancer cells,” Guo says. “By understanding the cellular mechanisms driving these responses, we can potentially develop strategies to disable this defense, allowing therapeutics to penetrate and attack the tumor more efficiently.”

The research builds on a prior collaboration between Guo and Mitchell’s labs, wherein the teams focused on how tumor-associated immune cells, known as macrophages, contribute to the suppression of anti-tumor immunity by secreting extracellular vesicles.

Read the full story in Penn Today.

Michael Mitchell is an associate professor in the Department of Bioengineering in the School of Engineering and Applied Science and director of the Lipid Nanoparticle Synthesis Core at the Penn Institute for RNA Innovation at the University of Pennsylvania.

Wei Guo is the Hirsch Family President’s Distinguished Professor in the Department of Biology in Penn’s School of Arts & Sciences.

Ningqiang Gong, a former postdoctoral researcher in the Mitchell lab at Penn Engineering, is an assistant professor at the University of Science and Technology of China.

Wenqun Zhong is a reseearch associate in the Guo Laboratory in Penn Arts & Sciences.

Other authors include: Alex G Hamilton, Dongyoon Kim, Junchao Xu, and Lulu Xue of Penn Engineering; Junhyong Kim, Zhiyuan Qin, and Fengyuan Xu of Penn Arts & Sciences; Mohamad-Gabriel Alameh and Drew Weissman of the Perelman School of Medicine; Andrew E. Vaughn and Gan Zhao of the Penn School of Veterinary Medicine; Jinghong Li and Xucong Teng of the University of Beijing; and Xing-Jie Liang of the Chinese Academy of Sciences.

This research received support from the U.S. National Institutes of Health (DP2 TR002776, R35 GM141832, and NCI P50 CA261608), Burroughs Wellcome Fund, U.S. National Science Foundation CAREER Award (CBET-2145491), and an American Cancer Society Research Scholar Grant (RGS-22-1122-01-ET.)

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Knockout of CD5 on CAR T Cells Boosts Anti-Tumor Efficacy

by Meagan Raeke

The effectiveness of CAR T cell therapy against a variety of cancers, including solid tumors, could be boosted greatly by using CRISPR-Cas9 technology to knock out the gene for CD5, a protein found on the surface of T cells, according to a preclinical study from investigators at the University of Pennsylvania’s Perelman School of Medicine and Abramson Cancer Center.

CAR T cells are T cells that have been engineered to attack specific targets found on cancer cells. They have had remarkable results in some patients with blood cancers. But they have not performed well against other cancers including solid-tumor cancers, such as pancreatic cancer, prostate cancer, and melanoma. Researchers have been searching for techniques to boost the effectiveness of CAR T cell therapy.

The study, published today in Science Immunology, suggests that knocking out CD5 could be a prime technique. Illuminating the protein’s previously murky role, the researchers found that it works as a powerful immune checkpoint, reining in T cell effectiveness. Removing it, they showed, dramatically enhanced CAR T cell anticancer activity in a variety of preclinical cancer models.

“We’ve discovered in preclinical models that CD5 deletion greatly enhances the function of CAR T cells against multiple cancers,” said senior author Marco Ruella, MD, an assistant professor of Hematology-Oncology, researcher with the Center for Cellular Immunotherapies and the scientific director of Penn Medicine’s Lymphoma Program. “The striking effects we observed across preclinical models suggest that CD5 knockout could be a general strategy for enhancing CAR T cell function.”

The study’s first author is Ruchi Patel, PhD, a recent graduate student from the Ruella Laboratory.

Read the full story in Penn Medicine News.

Marco Ruella is a member of the Penn Bioengineering Graduate Group. Read more stories featuring Ruella in the BE Blog.

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Shedding Light on Cellular Metabolism to Fight Disease

by Melissa Pappas

Enamored by the chemical processes of life, Yihui Shen, J. Peter and Geri Skirkanich Assistant Professor of Innovation in Bioengineering, started her research career as a chemist studying the way that proteins fold and the intricate dynamics underlying life processes.

“As an undergraduate, I studied physical chemistry, thinking that one day I’d be addressing challenges in hardcore STEM fields,” she says. “It wasn’t until I observed the dynamics of a single protein molecule that I fell in love with microscopy. I realized that this imaging tool could not only help us observe biological processes on a small scale, but it could also provide new insight at the interface of engineering, chemistry and physics and solve problems on a large scale.”

When Shen turned her attention to microscopy, the field itself was advancing quickly, with improvements being made and new techniques being released every month. Without missing a beat, Shen dove deeper into the most current tools available when she joined Dr. Wei Min’s lab at Columbia University as a doctoral student.

“Professor Wei Min is a pioneer in a new imaging technique called coherent Raman imaging,” says Shen. “In this type of microscopy, we focus light on a very specific point in the cell and measure the amount of scattered light that comes back after exchanging energy with the molecular vibration. This approach allows us to visualize the spatial distribution of different molecules, the very chemistry of life I had studied as an undergraduate, at a high enough resolution to gain insights into biological processes, such as tissue organization, drug distribution and cellular metabolism.”

With this new tool under her belt, Shen was able to ask the kinds of questions that could connect the use of this observation tool to practical applications for real-world challenges.

“I started thinking outside the box,” says Shen. “What if we could observe the chemical exchanges involved in metabolism as they are happening on the scale of a single cell, and then use that insight to pinpoint the exact metabolic pathways and molecules that facilitate tumor growth and disease?”

Read the full story in Penn Engineering Today.

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Penn Pioneers a ‘One-Pot Platform’ to Promptly Produce mRNA Delivery Particles

by Nathi Magubane

Lipid nanoparticles present one of the most advanced drug delivery platforms to shuttle promising therapeutics such as mRNA but are limited by the time it takes to synthesize cationic lipids, a key component. Now, Michael Mitchell and his team at the School of Engineering and Applied Science have developed a faster way to make cationic lipids that are also more versatile, able to carry different kinds of treatments to target specific organs. (Image: iStock / Dr_Microbe)

Imagine a scenario where a skilled hacker must upload critical software to update a central server and thwart a potentially lethal virus from wreaking havoc across a vast computer network. The programmer, armed with the lifesaving code, must navigate through treacherous territory teeming with adversaries, and success hinges on promptly getting a safe, stealthy delivery vehicle that can place the hacker exactly where they need to be.

In the context of modern medicine, messenger RNA (mRNA) serves as the hacker, carrying genetic instructions to produce specific proteins within cells that can induce desired immune responses or sequester maladaptive cellular elements. Lipid nanoparticles (LNPs) are the stealthy delivery vehicles that transport these fragile mRNA molecules through the bloodstream to their target cells, overcoming the body’s defenses to deliver their payload safely and efficiently.

However, much like building an advanced stealth vehicle, the synthesis of cationic lipids—a type of lipid molecule that’s positively charged and a key component of LNPs—is often a time-consuming process, involving multiple steps of chemical synthesis and purification.

Now, Michael Mitchell and a team at the University of Pennsylvania have addressed this challenge with a novel approach that leverages a compound library fabrication technique known as “click-like chemistry” to create LNPs in a single, simple step. Their findings, published in the journal Nature Chemistry, show that this method not only speeds up the synthesis process but also presents a way to equip these delivery vehicles with a “GPS” to better target specific organs such as the liver, lungs, and spleen, potentially opening new avenues for treating a range of diseases that arise in these organs.

“We’ve developed what we call an amidine-incorporated degradable (AID) lipid, a uniquely structured biodegradable molecule,” Mitchell says. “Think of it as an easy-to-build custom mRNA vehicle with a body kit that informs its navigation system. By adjusting its shape and degradability, we can enhance mRNA delivery into cells in a safe manner. By adjusting the amount of the AID lipid that we incorporate into the LNP, we can also guide it to different organs in the body, much like programming different destinations into a GPS.”

First author Xuexiang Han, a former postdoctoral researcher in the Mitchell Lab, explains that their new approach allows the rapid creation of diverse lipid structures in just an hour, compared to the weekslong process traditionally required.

Read more in Penn Today.

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Honoring a Life Scientist’s Lifesaving Science

by Nathi Magubane

Carl June (center) is awarded the 2024 Breakthrough Prize in Life Sciences. His innovative contributions to CAR T cell therapy have transformed the approach to treating certain cancers. His co-recipient is Michel Sadelain of Sloan Kettering Memorial Hospital (right). Flanking them on the stage are (from left to right) Olivia Wilde, Camille Leahy, and Regina King. (Image: Courtesy of Breakthrough Prize)

In his acceptance speech for the 2024 Breakthrough Prize in Life Sciences, Carl June, a pioneer in cancer treatment, highlighted the people most affected by his groundbreaking work developing CAR T cell immunotherapy: the patients. 

When all other cancer treatments failed them, said June, “instead of giving up, they pushed forward and volunteered for an unproven experimental new treatment. It’s because of these brave volunteers like our first patients Doug Olson, Bob Levis, and Emily Whitehead, that we have now treated over 34,000 cancer patients.” 

June, the Richard W. Vague Professor in Immunotherapy in Penn’s Perelman School of Medicine and director of the Center for Cellular Immunotherapies (CCI) at Penn Medicine’s Abramson Cancer Center, was honored at the 10th Breakthrough Prize awards ceremony for the development of chimeric antigen receptor (CAR) T cell immunotherapy. This is a cancer treatment approach in which each patient’s T cells are modified to target and kill their cancer cells.

Held on Saturday, April 13, and nicknamed the “Oscars of Science,” world-renowned researchers exchanged lab coats for tuxedos at the star-studded Breakthrough Prize awards ceremony hosted by Emmy Award-winning actor and comedian James Corden. Actors Olivia Wilde and Regina King handed June and his co-winner, Michel Sadelain of Memorial Sloan Kettering Cancer Center, the awards.

“We’re so grateful to have some recognition for a lot of years of work on cancer research,” said June at the event. “I think the best thing is that people learn about this, that this came out of research right here in the country. Now there’s been 34,000 people treated and it just started 10 years ago so people need to understand the value of research to make these new breakthrough therapies.” 

Read the full story in Penn Today.

Carl June is a member of the Penn Bioengineering Graduate Group. Read more stories featuring June in the BE Blog.

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Study Reveals Inequities in Access to Transformative CAR T Cell Therapy

Image: iStock/PeopleImages

Patients being treated for B-cell non-Hodgkin’s Lymphoma (NHL) who are part of minority populations may not have equal access to cutting-edge CAR T cell therapies, according to a new analysis led by researchers from the Perelman School of Medicine and published in NEJM Evidence.

CAR T cell therapy is a personalized form of cancer therapy that was pioneered at Penn Medicine and has brought hope to thousands of patients who had otherwise run out of treatment options. Six different CAR T cell therapies have been approved since 2017 for a variety of blood cancers, including B-cell NHL that has relapsed or stopped responding to treatment. Image: iStock/PeopleImages

“CAR T cell therapy represents a major leap forward for blood cancer treatment, with many patients living longer than ever before, but its true promise can only be realized if every patient in need has access to these therapies,” says lead author Guido Ghilardi, a postdoctoral fellow in the laboratory of senior author Marco Ruella, an assistant professor of hematology-oncology and scientific director of the Lymphoma Program. “From the scientific perspective, we’re constantly working in the laboratory to make CAR T cell therapy work better, but we also want to make sure that when a groundbreaking treatment like this becomes available, it reaches all patients who might be able to benefit.”

Read the full story in Penn Medicine News.

Marco Ruella is a member of the Penn Bioengineering Graduate Group. Read more stories featuring Ruella in the BE Blog.

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Scientists Discover a Key Quality-Control Mechanism in DNA Replication

by Meagan Raeke

Illustration of the 55LCC complex. (Image: Courtesy of Cameron Baines/Phospho Biomedical Animation)

When cells in the human body divide, they must first make accurate copies of their DNA. The DNA replication exercise is one of the most important processes in all living organisms and is fraught with risks of mutation, which can lead to cell death or cancer. Now, findings from biologists from the Perelman School of Medicine and from the University of Leeds have identified a multiprotein “machine” in cells that helps govern the pausing or stopping of DNA replication to ensure its smooth progress. Illustration of the 55LCC complex. (Image: Courtesy of Cameron Baines/Phospho Biomedical Animation)

The discovery, published in Cell, advances the understanding of DNA replication, helps explain a puzzling set of genetic diseases, and could inform the development of future treatments for neurologic and developmental disorders.

“We’ve found what appears to be a critical quality-control mechanism in cells,” says senior co-corresponding author Roger Greenberg, the J. Samuel Staub, M.D. Professor in the department of Cancer Biology, director of the Penn Center for Genome Integrity, and director of basic science at the Basser Center for BRCA at Penn Medicine. “Trillions of cells in our body divide every single day, and this requires accurate replication of our genomes. Our work describes a new mechanism that regulates protein stability in replicating DNA. We now know a bit more about an important step in this complex biological process.”

Read the full story at Penn Medicine News.

Greenberg is a member of the Penn Bioengineering Graduate Group.

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Accelerating CAR T Cell Therapy: Lipid Nanoparticles Speed Up Manufacturing

by Ian Scheffler

Visualization of a CAR T cell (in red) attacking a cancer cell (in blue) (Meletios Varras via Getty Images)

For patients with certain types of cancer, CAR T cell therapy has been nothing short of life changing. Developed in part by Carl June, Richard W. Vague Professor at Penn Medicine, and approved by the Food and Drug Administration (FDA) in 2017, CAR T cell therapy mobilizes patients’ own immune systems to fight lymphoma and leukemia, among other cancers.

However, the process for manufacturing CAR T cells themselves is time-consuming and costly, requiring multiple steps across days. The state of the art involves extracting patients’ T cells, then activating them with tiny magnetic beads, before giving the T cells genetic instructions to make chimeric antigen receptors (CARs), the specialized receptors that help T cells eliminate cancer cells.

Now, Penn Engineers have developed a novel method for manufacturing CAR T cells, one that takes just 24 hours and requires only one step, thanks to the use of lipid nanoparticles (LNPs), the potent delivery vehicles that played a critical role in the Moderna and Pfizer-BioNTech COVID-19 vaccines.

In a new paper in Advanced Materials, Michael J. Mitchell, Associate Professor in Bioengineering, describes the creation of “activating lipid nanoparticles” (aLNPs), which can activate T cells and deliver the genetic instructions for CARs in a single step, greatly simplifying  the CAR T cell manufacturing process. “We wanted to combine these two extremely promising areas of research,” says Ann Metzloff, a doctoral student in Bioengineering and NSF Graduate Research Fellow in the Mitchell lab and the paper’s lead author. “How could we apply lipid nanoparticles to CAR T cell therapy?”

Read the full story in Penn Engineering Today.

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“Switchable” Bispecific Antibodies Pave Way for Safer Cancer Treatment

by Nathi Magubane

Bispecific T cell engagers are emerging as a powerful class of immunotherapy to treat cancer but are sometimes hindered by unwanted outcomes, such as on-target, off-tumor toxicity; cytokine release syndrome; and neurotoxicity. Now, researchers Penn researchers have developed a novel “switchable” bispecific T cell engager that mitigates these negative effects by co-opting a drug already approved by the FDA. (Image: iStock / CIPhotos)

In the ever-evolving battle against cancer, immunotherapy presents a turning point. It began with harnessing the body’s immune system to fight cancer, a concept rooted more than a century ago but only gaining significant momentum in recent years. Pioneering this shift were therapies like CAR T cell therapy, which reprograms a patient’s T cells to attack cancer cells. Within this domain, bispecific T cell engagers, or bispecific antibodies, have emerged as effective treatments for many blood-borne cancers in the clinic and are being evaluated for solid tumor therapy.

These antibodies simultaneously latch onto both a cancer cell and a T cell, effectively bridging the gap between the two. This proximity triggers the T cells to unleash their lethal arsenal, thereby killing the cancer cells. However, bispecific T cell engagers, like many cancer therapies, face hurdles such as cell-specific targeting limitations, known as on-target off-tumor toxicity, which means the tumor is correctly targeted but so are other healthy cells in the body, leading to healthy tissue damage. Moreover, bispecific antibodies may also lead to immune system overactivation, a precursor for cytokine release syndrome (CRS), and neurotoxicity.

Now, researchers led by Michael Mitchell of the University of Pennsylvania have found a way to circumvent many of these deleterious effects by developing a bispecific T cell nanoengager that is equipped with an “off switch.” Their findings are published in Nature Biomedical Engineering.

“We’re excited to show that bispecific antibodies can be tweaked in a way that allows us to tap into their powerful cancer-killing potential without inducing toxicity to healthy tissues,” says Mitchell, associate professor of bioengineering at Penn’s School of Engineering and Applied Science. “This new controllable drug-delivery mechanism, which we call switchable bispecific T cell nanoengagers, or SiTEs, adds this switchable component to the antibody via administering an FDA-approved small-molecule drug, amantadine.”

Read the full story in Penn Today.

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What Makes a Breakthrough? “Eight Steps Back” Before Making it to the Finish Lit

by Meagan Raeke

(From left to right) Breakthrough Prize recipients Drew Weissman, Virginia M-Y Lee, Katalin Karikó, and Carl June at a reception on Feb. 13. (Image: Courtesy of Penn Medicine News)

In popular culture, scientific discovery is often portrayed in “Eureka!” moments of sudden realization: a lightbulb moment, coming sometimes by accident. But in real life—and in Penn Medicine’s rich history as a scientific innovator for more than 250 years—scientific breakthroughs can never truly be distilled down to a single, “ah-ha” moment. They’re the result of years of hard work, perseverance, and determination to keep going, despite repeated, often discouraging, barriers and setbacks. 

“Research is [like taking], four, or six, or eight steps back, and then a little stumble forward,” said Drew Weissman, MD, PhD, the Roberts Family Professor of Vaccine Research. “You keep doing that over and over and somehow, rarely, you can get to the top of the step.” 

For Weissman and his research partner, Katalin Karikó, PhD, an adjunct professor of Neurosurgery, that persistence—documented in thousands of news stories across the globe—led to the mRNA technology that enabled two lifesaving COVID-19 vaccines, earning the duo numerous accolades, including the highest scientific honor, the 2023 Nobel Prize in Medicine. 

Weissman and Karikó were also the 2022 recipients of the Breakthrough Prize in Life Sciences, the world’s largest science awards, popularly known as the “Oscars of Science.” Founded in 2012 by a group of web and tech luminaries including Google co-founder Sergey Brin and Meta CEO Mark Zuckerberg, the Breakthrough Prizes recognize “the world’s top scientists working in the fundamental sciences—the disciplines that ask the biggest questions and find the deepest explanations.” With six total winners, including four from the Perelman School of Medicine (PSOM), Penn stands alongside Harvard and MIT as the institutions whose researchers have been honored with the most Breakthrough Prizes. 

Virginia M.–Y. Lee, PhD, the John H. Ware 3rd Professor in Alzheimer’s Research, was awarded the Prize in 2020 for discovering how different forms of misfolded proteins can move from cell to cell and lead to neurodegenerative disease progression. Carl June, MD, the Richard W. Vague Professor in Immunotherapy, is the most recent recipient and will be recognized at a star-studded red-carpet event in April for pioneering the development of CAR T cell therapy, which programs patients’ own immune cells to fight their cancer.

The four PSOM Breakthrough Prize recipients were honored on Tuesday, Feb. 13, 2024, when a new large-scale installation was unveiled in the lobby of the Biomedical Research Building to celebrate each laurate and their life-changing discoveries. During a light-hearted panel discussion, the honorees shared how a clear purpose, dogged determination, and a good sense of humor enabled their momentum forward. 

Read the full story in Penn Medicine News.

Carl June and Jon Epstein are members of the Penn Bioengineering Graduate Group. Read more stories featuring them in the BE Blog here and here, respectively.

Weissman presented the Department of Bioengineering’s 2022 Herman P. Schwan Distinguished Lecture: “Nucleoside-modified mRNA-LNP therapeutics.” Read more stories featuring Weissman in the BE Blog here.