A Suit of Armor for Cancer-fighting Cells

by Nathi Magubane

Chimeric antigen receptor T cell (CAR T) therapy has delivered promising results, transforming the fight against various forms of cancer, but for many, the therapy comes with severe and potentially lethal side effects. Now, a research team led by Michael Mitchell of the School of Engineering and Applied Science has found a solution that could help CAR T therapies reach their full potential while minimizing severe side effects. (Image: iStock / Meletios Verras)

In recent years, cancer researchers have hailed the arrival of chimeric antigen receptor T cell (CAR T) therapy, which has delivered promising results, transforming the fight against various forms of cancer. The process involves modifying patients’ T-cells to target cancer cells, resulting in remarkable success rates for previously intractable forms of cancer.

Six CAR T cell therapies have secured FDA approval, and several more are in the pipeline. However, these therapies come with severe and potentially lethal side effects, namely cytokine release syndrome (CRS) and neurotoxicity. These drawbacks manifest as a range of symptoms—from high fever and vomiting to multiple organ failure and patient death—posing significant challenges to broader clinical application.

Now, a research team led by Michael Mitchell, associate professor in the School of Engineering and Applied Science at the University of Pennsylvania, has found a solution that could help CAR T therapies reach their full potential while minimizing severe side effects. Their findings are published in the journal Nature Materials.

“Addressing CRS and neurotoxicity without compromising the therapeutic effectiveness of CAR T cells has been a complex challenge,” says Mitchell.

He says that unwanted interactions between CAR T and immune cells called macrophages drive the overactivation of macrophages, which in turn result in the release of toxic cytokines that lead to CRS and neurotoxicity.

“Controlling CAR T-macrophage interactions in vivo is difficult,” Mitchell says. “So, our study introduces a materials engineering-based strategy that involves incorporating a sugar molecule onto the surface of CAR T cells. These sugars are then used as a reactive handle to create a biomaterial coating around these cells directly in the body, which acts as a ‘suit of armor,’ preventing dangerous interactions with macrophages.”

First author Ningqiang Gong, a postdoctoral researcher in the Mitchell Lab, elaborates on the technique, “We attached this sugar molecule to the CAR T cells using metabolic labeling. This modification enables the CAR T cells to attack cancer cells without any hindrance.”

“When symptoms of CRS begin to manifest, we introduce another molecule—polyethylene glycol (PEG)—to create the suit of armor, which effectively blocks dangerous interactions between these engineered T cells, macrophages, and the tumor cells themselves,” Gong says.

Read the full story in Penn Today.

An Improved Delivery System for mRNA Vaccines Provides More Powerful Protection

by Devorah Fischler

(From left to right) Xuexiang Han, Michael Mitchell and Mohamad-Gabriel Alameh

The COVID-19 vaccine swiftly undercut the worst of the pandemic for hundreds of millions around the world. Available sooner than almost anyone expected, these vaccines were a triumph of resourcefulness and skill.

Messenger RNA vaccines, like the ones manufactured by Moderna or Pfizer/BioNTech, owed their speed and success to decades of research reinforcing the safety and effectiveness of their unique immune-instructive technology.

Now, researchers from the University of Pennsylvania School of Engineering and Applied Science and the Perelman School of Medicine are refining the COVID-19 vaccine, creating an innovative delivery system for even more robust protection against the virus.

In addition to outlining a more flexible and effective COVID-19 vaccine, this work has potential to increase the scope of mRNA vaccines writ large, contributing to prevention and treatment for a range of different illnesses.

Michael Mitchell, associate professor in Penn Engineering’s Department of Bioengineering, Xuexiang Han, postdoctoral fellow in Mitchell’s lab, and Mohamad-Gabriel Alameh, postdoctoral fellow in Drew Weissman’s lab at Penn Medicine and incoming assistant professor in the Department of Pathology and Laboratory Medicine at the Perelman School of Medicine, recently published their findings in Nature Nanotechnology.

mRNA, or messenger ribonucleic acid, is the body’s natural go-between. mRNA contains the instructions our cells need to produce proteins that play important roles in our bodies’ health, including mounting immune responses.

The COVID-19 vaccines follow suit, sending a single strand of RNA to teach our cells how to recognize and fight the virus.

Read the full story in Penn Engineering Today.

Charting a Path Forward with Unifying Definition of Cytokine Storm

by Melissa Moody

Penn Medicine researchers have developed a unifying definition of ‘cytokine storm’ to provide a framework to assess and treat patients whose immune systems have gone rogue.

Penn Medicine’s David Fajgenbaum (left) and Carl June (right). (Image: Penn Medicine News)

One of the most elusive aspects for clinicians treating COVID-19 is the body’s immune response to the virus. In the most severe cases of COVID-19, the immune system goes into overdrive, resulting in a fever, multiorgan system damage, and often death—a cytokine storm. But how to detect and treat a cytokine storm requires that clinicians can identify it as such.

Two Penn Medicine researchers have developed a unifying definition of “cytokine storm” to provide physicians with a framework to assess and treat severely-ill patients whose immune systems have gone rogue. Cytokine storms can be triggered by different pathogens, disorders, or treatments, from COVID-19 to Castleman disease to CAR T cell therapy.

In a paper published in the New England Journal of Medicine, David Fajgenbaum, an assistant professor of translational medicine & human genetics and director of the Center for Cytokine Storm Treatment & Laboratory (CSTL), and Carl June, a professor of pathology and laboratory medicine and director of the Center for Cellular Immunotherapies in the Abramson Cancer Center, and the Parker Institute for Cancer Immunotherapies define a cytokine storm as requiring elevated circulating cytokine levels, acute systemic inflammatory symptoms, and secondary organ dysfunction beyond what could be attributed to a normal response to a pathogen, if a pathogen is present.

“There has never been a defining central review of what a cytokine storm is and how to treat one, and now with COVID-19, that is a major issue,” says Fajgenbaum, a Castleman disease patient who has previously experienced five cytokine storms himself. “I’ve spent the last 10 years of my life as a cytokine storm patient and researcher, so I know the importance of having a comprehensive unified definition to find therapies that work across the various types of cytokine storms.”

There is widespread recognition that the immune response to a pathogen, but not the pathogen itself, can contribute to multiorgan dysfunction and other symptoms. Additionally, similar cytokine storm syndromes can occur with no obvious infection.

Read more at Penn Medicine News.

NB: Carl June is a member of the Penn Bioengineering Graduate Group.