Author: mantulin

CHARMed collaboration creates a potent therapy candidate for fatal prion diseases

A new gene-silencing tool shows promise as a future therapy against prion diseases and paves the way for new approaches to treating disease.

Greta Friar | Whitehead Institute
June 27, 2024

Drug development is typically slow: The pipeline from basic research discoveries that provide the basis for a new drug to clinical trials and then production of a widely available medicine can take decades. But decades can feel impossibly far off to someone who currently has a fatal disease. Broad Institute of MIT and Harvard Senior Group Leader Sonia Vallabh is acutely aware of that race against time, because the topic of her research is a neurodegenerative and ultimately fatal disease — fatal familial insomnia, a type of prion disease — that she will almost certainly develop as she ages.

Vallabh and her husband, Eric Minikel, switched careers and became researchers after they learned that Vallabh carries a disease-causing version of the prion protein gene and that there is no effective therapy for fatal prion diseases. The two now run a lab at the Broad Institute, where they are working to develop drugs that can prevent and treat these diseases, and their deadline for success is not based on grant cycles or academic expectations but on the ticking time bomb in Vallabh’s genetic code.

That is why Vallabh was excited to discover, when she entered into a collaboration with Whitehead Institute for Biomedical Research member Jonathan Weissman, that Weissman’s group likes to work at full throttle. In less than two years, Weissman, Vallabh, and their collaborators have developed a set of molecular tools called CHARMs that can turn off disease-causing genes such as the prion protein gene — as well as, potentially, genes coding for many other proteins implicated in neurodegenerative and other diseases — and they are refining those tools to be good candidates for use in human patients. Although the tools still have many hurdles to pass before the researchers will know if they work as therapeutics, the team is encouraged by the speed with which they have developed the technology thus far.

“The spirit of the collaboration since the beginning has been that there was no waiting on formality,” Vallabh says. “As soon as we realized our mutual excitement to do this, everything was off to the races.”

Co-corresponding authors Weissman and Vallabh and co-first authors Edwin Neumann, a graduate student in Weissman’s lab, and Tessa Bertozzi, a postdoc in Weissman’s lab, describe CHARM — which stands for Coupled Histone tail for Autoinhibition Release of Methyltransferase — in a paper published today in the journal Science.

“With the Whitehead and Broad Institutes right next door to each other, I don’t think there’s any better place than this for a group of motivated people to move quickly and flexibly in the pursuit of academic science and medical technology,” says Weissman, who is also a professor of biology at MIT and a Howard Hughes Medical Institute Investigator. “CHARMs are an elegant solution to the problem of silencing disease genes, and they have the potential to have an important position in the future of genetic medicines.”

To treat a genetic disease, target the gene

Prion disease, which leads to swift neurodegeneration and death, is caused by the presence of misshapen versions of the prion protein. These cause a cascade effect in the brain: the faulty prion proteins deform other proteins, and together these proteins not only stop functioning properly but also form toxic aggregates that kill neurons. The most famous type of prion disease, known colloquially as mad cow disease, is infectious, but other forms of prion disease can occur spontaneously or be caused by faulty prion protein genes.

Most conventional drugs work by targeting a protein. CHARMs, however, work further upstream, turning off the gene that codes for the faulty protein so that the protein never gets made in the first place. CHARMs do this by epigenetic editing, in which a chemical tag gets added to DNA in order to turn off or silence a target gene. Unlike gene editing, epigenetic editing does not modify the underlying DNA — the gene itself remains intact. However, like gene editing, epigenetic editing is stable, meaning that a gene switched off by CHARM should remain off. This would mean patients would only have to take CHARM once, as opposed to protein-targeting medications that must be taken regularly as the cells’ protein levels replenish.

Research in animals suggests that the prion protein isn’t necessary in a healthy adult, and that in cases of disease, removing the protein improves or even eliminates disease symptoms. In a person who hasn’t yet developed symptoms, removing the protein should prevent disease altogether. In other words, epigenetic editing could be an effective approach for treating genetic diseases such as inherited prion diseases. The challenge is creating a new type of therapy.

Fortunately, the team had a good template for CHARM: a research tool called CRISPRoff that Weissman’s group previously developed for silencing genes. CRISPRoff uses building blocks from CRISPR gene editing technology, including the guide protein Cas9 that directs the tool to the target gene. CRISPRoff silences the targeted gene by adding methyl groups, chemical tags that prevent the gene from being transcribed, or read into RNA, and so from being expressed as protein. When the researchers tested CRISPRoff’s ability to silence the prion protein gene, they found that it was effective and stable.

Several of its properties, though, prevented CRISPRoff from being a good candidate for a therapy. The researchers’ goal was to create a tool based on CRISPRoff that was just as potent but also safe for use in humans, small enough to deliver to the brain, and designed to minimize the risk of silencing the wrong genes or causing side effects.

From research tool to drug candidate

Led by Neumann and Bertozzi, the researchers began engineering and applying their new epigenome editor. The first problem that they had to tackle was size, because the editor needs to be small enough to be packaged and delivered to specific cells in the body. Delivering genes into the human brain is challenging; many clinical trials have used adeno-associated viruses (AAVs) as gene-delivery vehicles, but these are small and can only contain a small amount of genetic code. CRISPRoff is way too big; the code for Cas9 alone takes up most of the available space.

The Weissman lab researchers decided to replace Cas9 with a much smaller zinc finger protein (ZFP). Like Cas9, ZFPs can serve as guide proteins to direct the tool to a target site in DNA. ZFPs are also common in human cells, meaning they are less likely to trigger an immune response against themselves than the bacterial Cas9.

Next, the researchers had to design the part of the tool that would silence the prion protein gene. At first, they used part of a methyltransferase, a molecule that adds methyl groups to DNA, called DNMT3A. However, in the particular configuration needed for the tool, the molecule was toxic to the cell. The researchers focused on a different solution: Instead of delivering outside DNMT3A as part of the therapy, the tool is able to recruit the cell’s own DNMT3A to the prion protein gene. This freed up precious space inside of the AAV vector and prevented toxicity.

The researchers also needed to activate DNMT3A. In the cell, DNMT3A is usually inactive until it interacts with certain partner molecules. This default inactivity prevents accidental methylation of genes that need to remain turned on. Neumann came up with an ingenious way around this by combining sections of DNMT3A’s partner molecules and connecting these to ZFPs that bring them to the prion protein gene. When the cell’s DNMT3A comes across this combination of parts, it activates, silencing the gene.

“From the perspectives of both toxicity and size, it made sense to recruit the machinery that the cell already has; it was a much simpler, more elegant solution,” Neumann says. “Cells are already using methyltransferases all of the time, and we’re essentially just tricking them into turning off a gene that they would normally leave turned on.”

Testing in mice showed that ZFP-guided CHARMs could eliminate more than 80 percent of the prion protein in the brain, while previous research has shown that as little as 21 percent elimination can improve symptoms.

Once the researchers knew that they had a potent gene silencer, they turned to the problem of off-target effects. The genetic code for a CHARM that gets delivered to a cell will keep producing copies of the CHARM indefinitely. However, after the prion protein gene is switched off, there is no benefit to this, only more time for side effects to develop, so they tweaked the tool so that after it turns off the prion protein gene, it then turns itself off.

Meanwhile, a complementary project from Broad Institute scientist and collaborator Benjamin Deverman’s lab, focused on brain-wide gene delivery and published in Science on May 17, has brought the CHARM technology one step closer to being ready for clinical trials. Although naturally occurring types of AAV have been used for gene therapy in humans before, they do not enter the adult brain efficiently, making it impossible to treat a whole-brain disease like prion disease. Tackling the delivery problem, Deverman’s group has designed an AAV vector that can get into the brain more efficiently by leveraging a pathway that naturally shuttles iron into the brain. Engineered vectors like this one make a therapy like CHARM one step closer to reality.

Thanks to these creative solutions, the researchers now have a highly effective epigenetic editor that is small enough to deliver to the brain, and that appears in cell culture and animal testing to have low toxicity and limited off-target effects.

“It’s been a privilege to be part of this; it’s pretty rare to go from basic research to therapeutic application in such a short amount of time,” Bertozzi says. “I think the key was forming a collaboration that took advantage of the Weissman lab’s tool-building experience, the Vallabh and Minikel lab’s deep knowledge of the disease, and the Deverman lab’s expertise in gene delivery.”

Looking ahead

With the major elements of the CHARM technology solved, the team is now fine-tuning their tool to make it more effective, safer, and easier to produce at scale, as will be necessary for clinical trials. They have already made the tool modular, so that its various pieces can be swapped out and future CHARMs won’t have to be programmed from scratch. CHARMs are also currently being tested as therapeutics in mice.

The path from basic research to clinical trials is a long and winding one, and the researchers know that CHARMs still have a way to go before they might become a viable medical option for people with prion diseases, including Vallabh, or other diseases with similar genetic components. However, with a strong therapy design and promising laboratory results in hand, the researchers have good reason to be hopeful. They continue to work at full throttle, intent on developing their technology so that it can save patients’ lives not someday, but as soon as possible.

Catalyst Symposium helps lower “activation barriers” for rising biology researchers

Second annual assembly, sponsored by the Department of Biology and Picower Institute, invited postdocs from across the country to meet with faculty, present their work to the MIT community, and build relationships.

Lillian Eden | Department of Biology
June 10, 2024

For science — and the scientists who practice it — to succeed, research must be shared. That’s why members of the MIT community recently gathered to learn about the research of eight postdocs from across the country for the second annual Catalyst Symposium, an event co-sponsored by the Department of Biology and The Picower Institute for Learning and Memory.

The eight Catalyst Fellows came to campus as part of an effort to increase engagement between MIT scholars and postdocs excelling in their respective fields from traditionally underrepresented backgrounds in science. The three-day symposium included panel discussions with faculty and postdocs, one-on-one meetings, social events, and research talks from the Catalyst Fellows.

“I love the name of this symposium because we’re all, of course, eager to catalyze advancements in our professional lives, in science, and to move forward faster by lowering activation barriers,” says MIT biology department head Amy Keating. “I feel we can’t afford to do science with only part of the talent pool, and I don’t think people can do their best work when they are worried about whether they belong.”

The 2024 Catalyst Fellows include Chloé Baron from Boston Children’s Hospital; Maria Cecília Canesso from The Rockefeller University; Kiara Eldred from the University of Washington School of Medicine; Caitlin Kowalski from the University of Oregon; Fabián Morales-Polanco from Stanford University; Kali Pruss from the Washington University School of Medicine in St. Louis; Rodrigo Romero from Memorial Sloan Kettering Cancer Center; and Zuri Sullivan from Harvard University.

Romero, who received his PhD from MIT working in the Jacks Lab at the Koch Institute, said that it was “incredible to see so many familiar faces,” but he spent the symposium lunch chatting with new students in his old lab.

“Especially having been trained to think differently after MIT, I can now reach out to people that I didn’t as a graduate student, and make connections that I didn’t think about before,” Romero says.

He presented his work on lineage plasticity in the tumor microenvironment. Lineage plasticity is a hallmark of tumor progression but also occurs during normal development, such as wound healing.

As for the general mission of the symposium, Romero agrees with Keating.

“Trying to lower the boundary for other people to actually have a chance to do academic research in the future is important,” Romero says.

The Catalyst Symposium is aimed at early-career scientists who foresee a path in academia. Of the 2023 Catalyst Fellows, one has already secured a faculty position. Starting this September, Shan Maltzer will be an assistant professor at Vanderbilt University in the Department of Pharmacology and the Vanderbilt Brain Institute studying mechanisms of somatosensory circuit assembly, development, and function.

Another aim of the Catalyst Symposium is to facilitate collaborations and strengthen existing relationships. Sullivan, an immunologist and molecular neuroscientist who presented on the interactions between the immune system and the brain, is collaborating with Sebastian Lourido, an associate professor of biology and core member of the Whitehead Institute for Biomedical Research. Lourido’s studies include pathogens such as Toxoplasma gondii, which is known to alter the behavior of infected rodents. In the long term, Sullivan hopes to bridge research in immunology and neuroscience — for instance by investigating how infection affects behavior. She has observed that two rodents experiencing illness will huddle together in a cage, whereas an unafflicted rodent and an ill one will generally avoid each other when sharing the same space.

Pruss presented research on the interactions between the gut microbiome and the environment, and how they may affect physiology and fetal development. Kowalski discussed the relationship between fungi residing on our bodies and human health. Beyond the opportunity to deliver talks, both agreed that the small group settings of the three-day event were rewarding.

“The opportunity to meet with faculty throughout the symposium has been invaluable, both for finding familiar faces and for establishing friendly relationships,” Pruss says. “You don’t have to try to catch them when you’re running past them in the hallway.”

Eldred, who studies cell fate in the human retina, says she was excited about the faculty panels because they allowed her to ask faculty about fundamental aspects of recruiting for their labs, like bringing in graduate students.

Kowalski also says she enjoyed interfacing with so many new ideas — the spread of scientific topics from among the cohort of speakers extended beyond those she usually interacts with.

Mike Laub, professor of biology and Howard Hughes Medical Institute investigator, and Yadira Soto-Feliciano, assistant professor of biology and intramural faculty at the Koch Institute for Integrative Cancer Research, were on the symposium’s planning committee, along with Diversity, Equity, and Inclusion Officer Hallie Dowling-Huppert. Laub hopes the symposium will continue to be offered annually; next year’s Catalyst Symposium is already scheduled to take place in early May.

“I thought this year’s Catalyst Symposium was another great success. The talks from the visiting fellows featured some amazing science from a wide range of fields,” Laub says. “I also think it’s fair to say that their interactions with the faculty, postdocs, and students here generated a lot of excitement and energy in our community, which is exactly what we hoped to accomplish with this symposium.”

John Fucillo: Laying foundations for MIT’s Department of Biology

The Building 68 manager’s leadership, innovation, and laid-back attitude have helped to build a strong culture of community.

Samantha Edelen | Department of Biology
June 6, 2024

When you enter John Fucillo’s office at MIT, you will likely be greeted with an amiable nose boop and wagging tail from Shadow, a 4-year-old black lab, followed by a warm welcome from the office’s human occupant. Fucillo, manager of Building 68 — home to the MIT Department of Biology — is an animal lover, and Shadow is the gentlest of roughly nine dogs and one Siamese cat he’s taken care of throughout his life. Fortunately for the department, Shadow is not the only lab Fucillo cares for.

Fucillo came to MIT Biology in 1989 and says he couldn’t be happier. A Boston-area local, Fucillo previously spent two years working at Revere Beach, then learned skills as an auto mechanic, and later completed an apprenticeship with the International Brotherhood of Electrical Workers. As Building 68’s manager; environment, health, and safety coordinator; and chemical hygiene officer, Fucillo’s goal is to make workflows “easier, less expensive, more desirable, and more comfortable.” According to Mitchell Galanek, MIT radiation protection officer and Fucillo’s colleague for over 30 years, Fucillo was key for the department’s successful move into its new home when Building 68 was completed in 1994.

Throughout his time as a building manager, Fucillo has decreased routine spending and increased sustainability. He lowered the cost of lab coats by a whopping 92 percent — from $2,600 to $200 — with just one phone call to North Star, the building’s uniform/linens provider. Auditing the building’s plastic waste generation inspired the institute-wide MIT Lab Plastics Recycling Program, which now serves over 200 labs across campus. More than 50,000 pounds of plastic have been recycled in the last four years alone.

“John is not a cog in the wheel, but an integral part of the whole system,” says Anthony Fuccione, technical instructor and manager of the Biology Teaching lab.

Connecting and leading

Fucillo says one of his favorite parts of the job is chatting with researchers and helping them achieve their goals. He reportedly clocks about 10,000 steps per day on campus, responding to requests from labs, collaborating with colleagues, and connecting Biology to the Institute’s Environment, Health, and Safety (EHS) office.

“John is called upon — literally and figuratively — morning, noon, and night,” says Whitehead Professor of Molecular Genetics Monty Krieger. “He has had to become an expert in so very many areas to support staff, faculty, and students. His enormous success is due in part to his technical talents, in part to his genuine care for the welfare of his colleagues, and in part to his very special and caring personality.”

When MIT needed to comply with the Environmental Protection Agency’s decree to improve safety standards across campus, Fucillo sat on the committees tasked with meeting those standards while avoiding undue burden on researchers, establishing the Environmental Health and Safety Management system in 2002.

“From a safety perspective, that was one of the most challenging things MIT had to go through — but it came out at the end a better, safer, place,” says John Collins, EHS project technician and friend and colleague to Fucillo for over 20 years.

Fucillo later co-led the initiative for a 2011 overhaul of MIT’s management of regulated medical waste (RMW), such as Petri dishes, blood, and needles. Fucillo volunteered to pilot a new approach in Building 68 — despite a lukewarm response to the proposal from other biology EHS representatives, according to Galanek. This abundantly successful management system is now used by all MIT departments that generate RMW. It’s not only less expensive, but also does a better job at decontaminating waste than the previous management system.

“Anyone who has worked with John during his MIT career understands it is truly a privilege to partner with him,” Galanek says. “Not only does the work get done and done well, but you also gain a friend along the way.”

After consolidating a disparate group of individual lab assistants, Fucillo took on a supervisory role for the centralized staff tasked with cleaning glassware, preparing media, and ensuring consistency and sterility across Building 68 labs.

According to maintenance mechanic James (Jimmy) Carr, “you can’t find a better boss.”

“He’s just an easy-going guy,” says Karen O’Leary, who has worked with Fucillo for over 30 years. “My voice matters — I feel heard and respected by him.”

Looking forward

Although there are still many updates Fucillo hopes to see in Building 68, which will soon celebrate its 30th birthday, he is taking steps to cut back on his workload. He recently began passing on his knowledge to Facilities Manager and EHS Coordinator Cesar Duarte, who joined the department in 2023.

“It’s been a pleasure working alongside John and learning about the substantial role and responsibility he’s had in the biology department for the last three decades,” Duarte says. “Not only is John’s knowledge of Building 68 and the department’s history unparalleled, but his dedication to MIT and continued care and commitment to the health and well-being of the biology community throughout his career are truly remarkable.”

As he winds down his time at MIT, Fucillo hopes to spend more time on music, one of his earliest passions, which began when he picked up an accordion in first grade. He still plays guitar and bass nearly every day. When he rocks out at home more often, he’ll be leaving behind the foundations of innovation, leadership, and respect in Building 68.

New technique reveals how gene transcription is coordinated in cells

By capturing short-lived RNA molecules, scientists can map relationships between genes and the regulatory elements that control them.

Anne Trafton | MIT News
June 5, 2024

The human genome contains about 23,000 genes, but only a fraction of those genes are turned on inside a cell at any given time. The complex network of regulatory elements that controls gene expression includes regions of the genome called enhancers, which are often located far from the genes that they regulate.

This distance can make it difficult to map the complex interactions between genes and enhancers. To overcome that, MIT researchers have invented a new technique that allows them to observe the timing of gene and enhancer activation in a cell. When a gene is turned on around the same time as a particular enhancer, it strongly suggests the enhancer is controlling that gene.

Learning more about which enhancers control which genes, in different types of cells, could help researchers identify potential drug targets for genetic disorders. Genomic studies have identified mutations in many non-protein-coding regions that are linked to a variety of diseases. Could these be unknown enhancers?

“When people start using genetic technology to identify regions of chromosomes that have disease information, most of those sites don’t correspond to genes. We suspect they correspond to these enhancers, which can be quite distant from a promoter, so it’s very important to be able to identify these enhancers,” says Phillip Sharp, an MIT Institute Professor Emeritus and member of MIT’s Koch Institute for Integrative Cancer Research.

Sharp is the senior author of the new study, which appears today in Nature. MIT Research Assistant D.B. Jay Mahat is the lead author of the paper.

Hunting for eRNA

Less than 2 percent of the human genome consists of protein-coding genes. The rest of the genome includes many elements that control when and how those genes are expressed. Enhancers, which are thought to turn genes on by coming into physical contact with gene promoter regions through transiently forming a complex, were discovered about 45 years ago.

More recently, in 2010, researchers discovered that these enhancers are transcribed into RNA molecules, known as enhancer RNA or eRNA. Scientists suspect that this transcription occurs when the enhancers are actively interacting with their target genes. This raised the possibility that measuring eRNA transcription levels could help researchers determine when an enhancer is active, as well as which genes it’s targeting.

“That information is extraordinarily important in understanding how development occurs, and in understanding how cancers change their regulatory programs and activate processes that lead to de-differentiation and metastatic growth,” Mahat says.

However, this kind of mapping has proven difficult to perform because eRNA is produced in very small quantities and does not last long in the cell. Additionally, eRNA lacks a modification known as a poly-A tail, which is the “hook” that most techniques use to pull RNA out of a cell.

One way to capture eRNA is to add a nucleotide to cells that halts transcription when incorporated into RNA. These nucleotides also contain a tag called biotin that can be used to fish the RNA out of a cell. However, this current technique only works on large pools of cells and doesn’t give information about individual cells.

While brainstorming ideas for new ways to capture eRNA, Mahat and Sharp considered using click chemistry, a technique that can be used to join two molecules together if they are each tagged with “click handles” that can react together.

The researchers designed nucleotides labeled with one click handle, and once these nucleotides are incorporated into growing eRNA strands, the strands can be fished out with a tag containing the complementary handle. This allowed the researchers to capture eRNA and then purify, amplify, and sequence it. Some RNA is lost at each step, but Mahat estimates that they can successfully pull out about 10 percent of the eRNA from a given cell.

Using this technique, the researchers obtained a snapshot of the enhancers and genes that are being actively transcribed at a given time in a cell.

“You want to be able to determine, in every cell, the activation of transcription from regulatory elements and from their corresponding gene. And this has to be done in a single cell because that’s where you can detect synchrony or asynchrony between regulatory elements and genes,” Mahat says.

Timing of gene expression

Demonstrating their technique in mouse embryonic stem cells, the researchers found that they could calculate approximately when a particular region starts to be transcribed, based on the length of the RNA strand and the speed of the polymerase (the enzyme responsible for transcription) — that is, how far the polymerase transcribes per second. This allowed them to determine which genes and enhancers were being transcribed around the same time.

The researchers used this approach to determine the timing of the expression of cell cycle genes in more detail than has previously been possible. They were also able to confirm several sets of known gene-enhancer pairs and generated a list of about 50,000 possible enhancer-gene pairs that they can now try to verify.

Learning which enhancers control which genes would prove valuable in developing new treatments for diseases with a genetic basis. Last year, the U.S. Food and Drug Administration approved the first gene therapy treatment for sickle cell anemia, which works by interfering with an enhancer that results in activation of a fetal globin gene, reducing the production of sickled blood cells.

The MIT team is now applying this approach to other types of cells, with a focus on autoimmune diseases. Working with researchers at Boston Children’s Hospital, they are exploring immune cell mutations that have been linked to lupus, many of which are found in non-coding regions of the genome.

“It’s not clear which genes are affected by these mutations, so we are beginning to tease apart the genes these putative enhancers might be regulating, and in what cell types these enhancers are active,” Mahat says. “This is a tool for creating gene-to-enhancer maps, which are fundamental in understanding the biology, and also a foundation for understanding disease.”

The findings of this study also offer evidence for a theory that Sharp has recently developed, along with MIT professors Richard Young and Arup Chakraborty, that gene transcription is controlled by membraneless droplets known as condensates. These condensates are made of large clusters of enzymes and RNA, which Sharp suggests may include eRNA produced at enhancer sites.

“We picture that the communication between an enhancer and a promoter is a condensate-type, transient structure, and RNA is part of that. This is an important piece of work in building the understanding of how RNAs from enhancers could be active,” he says.

The research was funded by the National Cancer Institute, the National Institutes of Health, and the Emerald Foundation Postdoctoral Transition Award.

“Rosetta Stone” of cell signaling could expedite precision cancer medicine

An atlas of human protein kinases enables scientists to map cell signaling pathways with unprecedented speed and detail. Michael Yaffe, the David H. Koch Professor of Science at MIT, the director of the MIT Center for Precision Cancer Medicine, a member of MIT’s Koch Institute for Integrative Cancer Research, and a senior author of the new study published in Nature, is hoping to apply the comprehensive atlas of enzymes that regulate a wide variety of cellular activities to individual patients’ tumors to learn more about how the signaling states differ in cancer cancer, which could reveal new

Megan Scudellari | Koch Institute
June 3, 2024

A newly complete database of human protein kinases and their preferred binding sites provides a powerful new platform to investigate cell signaling pathways.

Culminating 25 years of research, MIT, Harvard University, and Yale University scientists and collaborators have unveiled a comprehensive atlas of human tyrosine kinases — enzymes that regulate a wide variety of cellular activities — and their binding sites.

The addition of tyrosine kinases to a previously published dataset from the same group now completes a free, publicly available atlas of all human kinases and their specific binding sites on proteins, which together orchestrate fundamental cell processes such as growth, cell division, and metabolism.

Now, researchers can use data from mass spectrometry, a common laboratory technique, to identify the kinases involved in normal and dysregulated cell signaling in human tissue, such as during inflammation or cancer progression.

“I am most excited about being able to apply this to individual patients’ tumors and learn about the signaling states of cancer and heterogeneity of that signaling,” says Michael Yaffe, who is the David H. Koch Professor of Science at MIT, the director of the MIT Center for Precision Cancer Medicine, a member of MIT’s Koch Institute for Integrative Cancer Research, and a senior author of the new study. “This could reveal new druggable targets or novel combination therapies.”

The study, published in Nature, is the product of a long-standing collaboration with senior authors Lewis Cantley at Harvard Medical School and Dana-Farber Cancer Institute, Benjamin Turk at Yale School of Medicine, and Jared Johnson at Weill Cornell Medical College.

The paper’s lead authors are Tomer Yaron-Barir at Columbia University Irving Medical Center, and MIT’s Brian Joughin, with contributions from Kontstantin Krismer, Mina Takegami, and Pau Creixell.

Kinase kingdom

Human cells are governed by a network of diverse protein kinases that alter the properties of other proteins by adding or removing chemical compounds called phosphate groups. Phosphate groups are small but powerful: When attached to proteins, they can turn proteins on or off, or even dramatically change their function. Identifying which of the almost 400 human kinases phosphorylate a specific protein at a particular site on the protein was traditionally a lengthy, laborious process.

Beginning in the mid 1990s, the Cantley laboratory developed a method using a library of small peptides to identify the optimal amino acid sequence — called a motif, similar to a scannable barcode — that a kinase targets on its substrate proteins for the addition of a phosphate group. Over the ensuing years, Yaffe, Turk, and Johnson, all of whom spent time as postdocs in the Cantley lab, made seminal advancements in the technique, increasing its throughput, accuracy, and utility.

Johnson led a massive experimental effort exposing batches of kinases to these peptide libraries and observed which kinases phosphorylated which subsets of peptides. In a corresponding Nature paper published in January 2023, the team mapped more than 300 serine/threonine kinases, the other main type of protein kinase, to their motifs. In the current paper, they complete the human “kinome” by successfully mapping 93 tyrosine kinases to their corresponding motifs.

Next, by creating and using advanced computational tools, Yaron-Barir, Krismer, Joughin, Takegami, and Yaffe tested whether the results were predictive of real proteins, and whether the results might reveal unknown signaling events in normal and cancer cells. By analyzing phosphoproteomic data from mass spectrometry to reveal phosphorylation patterns in cells, their atlas accurately predicted tyrosine kinase activity in previously studied cell signaling pathways.

For example, using recently published phosphoproteomic data of human lung cancer cells treated with two targeted drugs, the atlas identified that treatment with erlotinib, a known inhibitor of the protein EGFR, downregulated sites matching a motif for EGFR. Treatment with afatinib, a known HER2 inhibitor, downregulated sites matching the HER2 motif. Unexpectedly, afatinib treatment also upregulated the motif for the tyrosine kinase MET, a finding that helps explain patient data linking MET activity to afatinib drug resistance.

Actionable results

There are two key ways researchers can use the new atlas. First, for a protein of interest that is being phosphorylated, the atlas can be used to narrow down hundreds of kinases to a short list of candidates likely to be involved. “The predictions that come from using this will still need to be validated experimentally, but it’s a huge step forward in making clear predictions that can be tested,” says Yaffe.

Second, the atlas makes phosphoproteomic data more useful and actionable. In the past, researchers might gather phosphoproteomic data from a tissue sample, but it was difficult to know what that data was saying or how to best use it to guide next steps in research. Now, that data can be used to predict which kinases are upregulated or downregulated and therefore which cellular signaling pathways are active or not.

“We now have a new tool now to interpret those large datasets, a Rosetta Stone for phosphoproteomics,” says Yaffe. “It is going to be particularly helpful for turning this type of disease data into actionable items.”

In the context of cancer, phosophoproteomic data from a patient’s tumor biopsy could be used to help doctors quickly identify which kinases and cell signaling pathways are involved in cancer expansion or drug resistance, then use that knowledge to target those pathways with appropriate drug therapy or combination therapy.

Yaffe’s lab and their colleagues at the National Institutes of Health are now using the atlas to seek out new insights into difficult cancers, including appendiceal cancer and neuroendocrine tumors. While many cancers have been shown to have a strong genetic component, such as the genes BRCA1 and BRCA2 in breast cancer, other cancers are not associated with any known genetic cause. “We’re using this atlas to interrogate these tumors that don’t seem to have a clear genetic driver to see if we can identify kinases that are driving cancer progression,” he says.

Biological insights

In addition to completing the human kinase atlas, the team made two biological discoveries in their recent study. First, they identified three main classes of phosphorylation motifs, or barcodes, for tyrosine kinases. The first class is motifs that map to multiple kinases, suggesting that numerous signaling pathways converge to phosphorylate a protein boasting that motif. The second class is motifs with a one-to-one match between motif and kinase, in which only a specific kinase will activate a protein with that motif. This came as a partial surprise, as tyrosine kinases have been thought to have minimal specificity by some in the field.

The final class includes motifs for which there is no clear match to one of the 78 classical tyrosine kinases. This class includes motifs that match to 15 atypical tyrosine kinases known to also phosphorylate serine or threonine residues. “This means that there’s a subset of kinases that we didn’t recognize that are actually playing an important role,” says Yaffe. It also indicates there may be other mechanisms besides motifs alone that affect how a kinase interacts with a protein.

The team also discovered that tyrosine kinase motifs are tightly conserved between humans and the worm species C. elegans, despite the species being separated by more than 600 million years of evolution. In other words, a worm kinase and its human homologue are phosphorylating essentially the same motif. That sequence preservation suggests that tyrosine kinases are highly critical to signaling pathways in all multicellular organisms, and any small change would be harmful to an organism.

The research was funded by the Charles and Marjorie Holloway Foundation, the MIT Center for Precision Cancer Medicine, the Koch Institute Frontier Research Program via L. Scott Ritterbush, the Leukemia and Lymphoma Society, the National Institutes of Health, Cancer Research UK, the Brain Tumour Charity, and the Koch Institute Support (core) grant from the National Cancer Institute.

The beauty of biology

Senior Hanjun Lee planned to pursue chemistry at MIT. A course in genetics changed that.

Lillian Eden | Department of Biology
May 16, 2024

When Hanjun Lee arrived at MIT, he was set on becoming a Course 5 chemistry student. Based on his experience in high school, biology was all about rote memorization.

That changed when he took course 7.03 (Genetics), taught by then-professor Aviv Regev, now head and executive vice president of research and early development at Genentech, and Peter Reddien, professor of biology and core member and associate director of the Whitehead Institute for Biomedical Research.

He notes that friends from other schools don’t cite a single course that changed their major, but he’s not alone in choosing Course 7 because of 7.03.

“Genetics has this interesting force, especially in MIT biology. The department’s historical — and active — role in genetics research ties directly into the way the course is taught,” Lee says. “Biology is about logic, scientific reasoning, and posing the right questions.”

A few years later, as a teaching assistant for class 7.002 (Fundamentals of Experimental Molecular Biology), he came to value how much care MIT biology professors take in presenting the material for all offered courses.

“I really appreciate how much effort MIT professors put into their teaching,” Lee says. “As a TA, you realize the beauty of how the professors organize these things — because they’re teaching you in a specific way, and you can grasp the beauty of it — there’s a beauty in studying and finding the patterns in nature.”

An undertaking to apply

To attend MIT at all hadn’t exactly been a lifelong dream. In fact, it didn’t occur to Lee that he could or should apply until he represented South Korea at the 49th International Chemistry Olympiad, where he won a Gold Medal in 2017. There, he had the chance to speak with MIT alumni, as well as current and aspiring students. More than half of those aspiring students eventually enrolled, Lee among them.

“Before that, MIT was this nearly mythical institution, so that experience really changed my life,” Lee recalls. “I heard so many different stories from people with so many different backgrounds — all converging towards the same enthusiasm towards science.”

At the time, Lee was already attending medical school — a six-year undergraduate program in Korea — that would lead to a stable career in medicine. Attending MIT would involve both changing his career plans and uprooting his life, leaving all his friends and family behind.

His parents weren’t especially enthusiastic about his desire to study at MIT, so it was up to Lee to meet the application requirements. He woke up at 3 a.m. to find his own way to the only SAT testing site in South Korea — an undertaking he now recalls with a laugh. In just three months, he had gathered everything he needed; MIT was the only institution in the United States Lee applied to.

He arrived in Cambridge, Massachusetts, in 2018 but attended MIT only for a semester before returning to Korea for his two years of mandatory military service.

“During military service, my goal was to read as many papers as possible, because I wondered what topic of science I’m drawn to — and many of the papers I was reading were authored by people I recognized, people who taught biology at MIT,” Lee says. “I became really interested in cancer biology.”

Return to MIT

When he returned to campus, Lee pledged to do everything he could to meet with faculty and discuss their work. To that end, he joined the MIT Undergraduate Research Journal, allowing him to interview professors. He notes that most MIT faculty are enthusiastic about being contacted by undergraduate students.

Stateside, Lee also reached out to Michael Lawrence, an assistant professor of pathology at Harvard Medical School and assistant geneticist at Mass General Cancer Center, about a preprint concerning APOBEC, an enzyme Lee had studied at Seoul National University. Lawrence’s lab was looking into APOBEC and cancer evolution — and the idea that the enzyme might drive drug resistance to cancer treatment.

“Since he joined my lab, I’ve been absolutely amazed by his scientific talents,” Lawrence says. “Hanjun’s scientific maturity and achievements are extremely rare, especially in an undergraduate student.”

Lee has made new discoveries from genomic data and was involved in publishing a paper in Molecular Cell and a paper in Nature Genetics. In the latter, the lab identified the source of background noise in chromosome conformation capture experiments, a technique for analyzing chromatin in cells.

Lawrence thinks Lee “is destined for great leadership in science.” In the meantime, Lee has gained valuable insights into how much work these types of achievements require.

“Doing research has been rewarding, but it also taught me to appreciate that science is almost 100 percent about failures,” Lee says. “It is those failures that end up leading you to the path of success.”

Widening the scope

Lee’s personal motto is that to excel in a specific field, one must have a broad sense of what the entire field looks like, and suggests other budding scientists enroll in courses distant from their research area. He also says it was key to see his peers as collaborators rather than competitors, and that each student will excel in their own unique way.

“Your MIT experience is defined by interactions with others,” Lee says. “They will help identify and shape your path.”

For his accomplishments, Lee was recently named an American Association for Cancer Research Undergraduate Scholar. Last year, he also spoke at the Gordon Research Conference on Cell Growth and Proliferation about his work on the retinoblastoma gene product RB.

Encouraged by positive course evaluations during his time as a TA, Lee hopes to inspire other students in the future through teaching. Lee has recently decided to pursue a PhD in cancer biology at Harvard Medical School, although his interests remain broad.

“I want to explore other fields of biology as well,” he says. “I have so many questions that I want to answer.”

Although initially resistant, Lee’s mother and father are now “immensely proud to be MIT parents” and will be coming to Cambridge in May to celebrate Lee’s graduation.

“Throughout my years here, they’ve been able to see how I’ve changed,” he says. “I don’t think I’m a great scientist, yet, but I now have some sense of how to become one.”

Taking RNAi from interesting science to impactful new treatments

Alnylam Pharmaceuticals is translating the promise of RNA interference (RNAi) research into a new class of powerful, gene-based therapies. These days Alnylam is not the only company developing RNAi-based medicines, but it is still a pioneer in the field. The company’s founders — MIT Institute Professor Phil Sharp, Professor David Bartel, Professor Emeritus Paul Schimmel, and former MIT postdocs Thomas Tuschl and Phillip Zamore — see Alnylam as a champion for the field more broadly.

Zach Winn | MIT News
May 13, 2024

There are many hurdles to clear before a research discovery becomes a life-changing treatment for patients. That’s especially true when the treatments being developed represent an entirely new class of medicines. But overcoming those obstacles can revolutionize our ability to treat diseases.

Few companies exemplify that process better than Alnylam Pharmaceuticals. Alnylam was founded by a group of MIT-affiliated researchers who believed in the promise of a technology — RNA interference, or RNAi.

The researchers had done foundational work to understand how RNAi, which is a naturally occurring process, works to silence genes through the degradation of messenger RNA. But it was their decision to found Alnylam in 2002 that attracted the funding and expertise necessary to turn their discoveries into a new class of medicines. Since that decision, Alnylam has made remarkable progress taking RNAi from an interesting scientific discovery to an impactful new treatment pathway.

Today Alnylam has five medicines approved by the U.S. Food and Drug Administration (one Alnylam-discovered RNAi therapeutic is licensed to Novartis) and a rapidly expanding clinical pipeline. The company’s approved medicines are for debilitating, sometimes fatal conditions that many patients have grappled with for decades with few other options.

The company estimates its treatments helped more than 5,000 patients in 2023 alone. Behind that number are patient stories that illustrate how Alnylam has changed lives. A mother of three says Alnylam’s treatments helped her take back control of her life after being bed-ridden with attacks associated with the rare genetic disease acute intermittent porphyria (AIP). Another patient reported that one of the company’s treatments helped her attend her daughter’s wedding. A third patient, who had left college due to frequent AIP attacks, was able to return to school.

These days Alnylam is not the only company developing RNAi-based medicines. But it is still a pioneer in the field, and the company’s founders — MIT Institute Professor Phil Sharp, Professor David Bartel, Professor Emeritus Paul Schimmel, and former MIT postdocs Thomas Tuschl and Phillip Zamore — see Alnylam as a champion for the field more broadly.

“Alnylam has published more than 250 scientific papers over 20 years,” says Sharp, who currently serves as chair of Alnylam’s scientific advisory board. “Not only did we do the science, not only did we translate it to benefit patients, but we also described every step. We established this as a modality to treat patients, and I’m very proud of that record.”

Pioneering RNAi development

MIT’s involvement in RNAi dates back to its discovery. Before Andrew Fire PhD ’83 shared a Nobel Prize for the discovery of RNAi in 1998, he worked on understanding how DNA was transcribed into RNA, as a graduate student in Sharp’s lab.

After leaving MIT, Fire and collaborators showed that double-stranded RNA could be used to silence specific genes in worms. But the biochemical mechanisms that allowed double-stranded RNA to work were unknown until MIT professors Sharp, Bartel, and Ruth Lehmann, along with Zamore and Tuschl, published foundational papers explaining the process. The researchers developed a system for studying RNAi and showed how RNAi can be controlled using different genetic sequences. Soon after Tuschl left MIT, he showed that a similar process could also be used to silence specific genes in human cells, opening up a new frontier in studying genes and ultimately treating diseases.

“Tom showed you could synthesize these small RNAs, transfect them into cells, and get a very specific knockdown of the gene that corresponded to that the small RNAs,” Bartel explains. “That discovery transformed biological research. The ability to specifically knockdown a mammalian gene was huge. You could suddenly study the function of any gene you were interested in by knocking it down and seeing what happens. … The research community immediately started using that approach to study the function of their favorite genes in mammalian cells.”

Beyond illuminating gene function, another application came to mind.

“Because almost all diseases are related to genes, could we take these small RNAs and silence genes to treat patients?” Sharp remembers wondering.

To answer the question, the researchers founded Alnylam in 2002. (They recruited Schimmel, a biotech veteran, around the same time.) But there was a lot of work to be done before the technology could be tried in patients. The main challenge was getting RNAi into the cytoplasm of the patients’ cells.

“Through work in Dave Bartel and Phil Sharp’s lab, among others, it became evident that to make RNAi into therapies, there were three problems to solve: delivery, delivery, and delivery,” says Alnylam Chief Scientific Officer Kevin Fitzgerald, who has been with the company since 2005.

Early on, Alnylam collaborated with MIT drug delivery expert and Institute Professor Bob Langer. Eventually, Alnylam developed the first lipid nanoparticles (LNPs) that could be used to encase RNA and deliver it into patient cells. LNPs were later used in the mRNA vaccines for Covid-19.

“Alnylam has invested over 20 years and more than $4 billion in RNAi to develop these new therapeutics,” Sharp says. “That is the means by which innovations can be translated to the benefit of society.”

From scientific breakthrough to patient bedside

Alnylam received its first FDA approval in 2018 for treatment of the polyneuropathy of hereditary transthyretin-mediated amyloidosis, a rare and fatal disease. It doubled as the first RNAi therapeutic to reach the market and the first drug approved to treat that condition in the United States.

“What I keep in mind is, at the end of the day for certain patients, two months is everything,” Fitzgerald says. “The diseases that we’re trying to treat progress month by month, day by day, and patients can get to a point where nothing is helping them. If you can move their disease by a stage, that’s huge.”

Since that first treatment, Alnylam has updated its RNAi delivery system — including by conjugating small interfering RNAs to molecules that help them gain entry to cells — and earned approvals to treat other rare genetic diseases along with high cholesterol (the treatment licensed to Novartis). All of those treatments primarily work by silencing genes that encode for the production of proteins in the liver, which has proven to be the easiest place to deliver RNAi molecules. But Alnylam’s team is confident they can deliver RNAi to other areas of the body, which would unlock a new world of treatment possibilities. The company has reported promising early results in the central nervous system and says a phase one study last year was the first RNAi therapeutic to demonstrate gene silencing in the human brain.

“There’s a lot of work being done at Alnylam and other companies to deliver these RNAis to other tissues: muscles, immune cells, lung cells, etc.,” Sharp says. “But to me the most interesting application is delivery to the brain. We think we have a therapeutic modality that can very specifically control the activity of certain genes in the nervous system. I think that’s extraordinarily important, for diseases from Alzheimer’s to schizophrenia and depression.”

The central nervous system work is particularly significant for Fitzgerald, who watched his father struggle with Parkinson’s.

“Our goal is to be in every organ in the human body, and then combinations of organs, and then combinations of targets within individual organs, and then combinations of targets within multi-organs,” Fitzgerald says. “We’re really at the very beginning of what this technology is going do for human health.”

It’s an exciting time for the RNAi scientific community, including many who continue to study it at MIT. Still, Alnylam will need to continue executing in its drug development efforts to deliver on that promise and help an expanding pool of patients.

“I think this is a real frontier,” Sharp says. “There’s major therapeutic need, and I think this technology could have a huge impact. But we have to prove it. That’s why Alnylam exists: to pursue new science that unlocks new possibilities and discover if they can be made to work. That, of course, also why MIT is here: to improve lives.”

3 Questions: Professors Adam Martin and Joel Volman on updating MIT’s undergraduate curriculum

Professors Adam Martin and Joel Volman explain the genesis, scope, and objectives of the recently launched Task Force on the MIT Undergraduate Academic Program.

Office of the Vice Chancellor
March 19, 2024

In late February, Vice Chancellor for Undergraduate and Graduate Education Ian A. Waitz and Faculty Chair Mary Fuller announced the formation and launch of the Task Force on the MIT Undergraduate Academic Program (TFUAP). The effort fulfills a critical recommendation of the Task Force 2021 and Beyond RIC1 (Undergraduate Program) and draws upon several, prior foundational working groups — some focused on the current General Institute Requirements (GIRs) and others on updating recent studies for the purposes of this review.

In this interview, task force co-chairs Adam Martin, professor of biology, and Joel Voldman, the William R. Brody Professor of Electrical Engineering and Computer Science describe the TFUAP’s goals, approach, and next steps.

Q: The charge of the task force is quite ambitious, including “reviewing the current undergraduate academic program and considering improvements with a focus on both the curriculum and pedagogy.” Can you explain your approach?

Martin: For context, it’s important to know that the undergraduate program is multifaceted and consists of many components, including majors, electives, experiential learning, and of course the GIRs — arguably one of the best-known acronyms at MIT! Moreover, the GIRs include science core classes; humanities, arts, and social sciences classes; certain electives in science and engineering; and a lab requirement, each of which serves a slightly different purpose and dovetails with majors and minors in unique ways.

Some aspects of the academic program are determined by the faculty, either MIT-wide or within a particular department. Others can be customized by students, in consultation with faculty and staff advisors, from the broad array of curricular and co-curricular offerings at MIT. The task force will look holistically at all of these aspects, considering both what MIT requires of all students, and the options we make available as students chart their own paths.

As part of this holistic approach, the TFUAP will zero in on both content and pedagogy. Obviously, the content we cover is important; our goal must remain to provide undergraduates with the world-class education they expect. But how we teach is of fundamental importance, as well. The pedagogy we adopt should be inclusive, supported by research, and designed to help students not only understand what they are learning, but why they are learning it — how it relates to their majors, potential careers, and their lives.

Voldman: I think your question’s description of our charge as “ambitious” is noteworthy. We feel that the task force is ambitious, too, but perhaps in a different sense from the question. That is, we believe our job is to not only think about nuts-and-bolts issues of the academic program requirements but also to consider the big picture. What are the most expansive possibilities? How can we push the envelope? That’s the MIT way, after all.

Q: The task force is building upon quite a bit of past work and benefits from some major accomplishments recommended by Task Force 2021 (TF2021). For example, how does the creation of the Undergraduate Advising Center, and in general, the desire to provide more personal and professional support to all students, fit in with the potential updates to the undergraduate curriculum?

Martin: You’re absolutely right — our work benefits greatly from years of conversations focused on the undergraduate academic program, particularly in the last decade or so. These include the 2014 Task Force on the Future of Education; the 2018 Designing the First-Year Experience Class; Task Force 2021 and Beyond (TF2021); the Foundational Working Groups (part of the RIC 1 implementation) that have studied the existing MIT undergraduate program; and the Committee on the Undergraduate Program. The valuable work of these past committees and their findings will certainly inform our thought process.

In the past, groups that evaluated the undergraduate curriculum were also charged with tackling related topics, such as undergraduate advising or revamping classrooms. Taking on any one of these three issues is ambitious by any measure! What’s changed in the past decade is that advances have been made in these other critical areas, so the TFUAP can focus solely on curriculum and pedagogy. For example, thanks to recent accomplishments by TF2021 and others, we have implemented a new advising system for all undergraduates in the form of the Undergraduate Advising Center.

We envision the TFUAP being a highly collaborative process, bringing in voices across the entire Institute and beyond. We welcome input from members of the community via email at tfuap@mit.edu. We will also be reaching out to student groups, alumni, individual faculty, faculty groups, and administrative staff across the Institute to hear their perspectives.

Q: Part of what TFUAP will have to confront, no doubt, are some of the most pressing issues of our time, like the rise of computing and AI, climate change (what President Kornbluth calls an existential threat to our way of life), and the changing nature of learning (online, hybrid, etc.). How are you thinking about all of these factors?

Voldman: That is a good question! It’s early days, and our work is just beginning, but we know that these and other issues loom over all of us. For example, we are keenly aware of the influx of students into computing-related majors and classes, and we need to think deeply about the implications. Furthermore, we want a curriculum that prepares students for current and upcoming global challenges as well as changes in the technology and tools available to address those challenges. However, we can expect that our students will need to be agile and curious, lifelong learners, collaborative and compassionate teammates, and creative and thoughtful problem-solvers.

As we work with the community to design the next version of an MIT undergraduate education, it will be important to build a structure that can incorporate the biggest challenges and opportunities of the day, while staying flexible and responsive to an ever-evolving world.

Faculty Ömer Yilmaz and Seychelle Vos among MIT faculty selected for Cancer Grand Challenges

Joining three teams backed by a total of $75 million, MIT researchers will tackle some of cancer’s toughest challenges.

Bendta Schroeder | Koch Institute
March 18, 2024

Cancer Grand Challenges recently announced five winning teams for 2024, which included five researchers from MIT: Michael Birnbaum, Regina Barzilay, Brandon DeKosky, Seychelle Vos, and Ömer Yilmaz. Each team is made up of interdisciplinary cancer researchers from across the globe and will be awarded $25 million over five years.

Birnbaum, an associate professor in the Department of Biological Engineering, leads Team MATCHMAKERS and is joined by co-investigators Barzilay, the School of Engineering Distinguished Professor for AI and Health in the Department of Electrical Engineering and Computer Science and the AI faculty lead at the MIT Abdul Latif Jameel Clinic for Machine Learning in Health; and DeKosky, Phillip and Susan Ragon Career Development Professor of Chemical Engineering. All three are also affiliates of the Koch Institute for Integrative Cancer Research At MIT.

Team MATCHMAKERS will take advantage of recent advances in artificial intelligence to develop tools for personalized immunotherapies for cancer patients. Cancer immunotherapies, which recruit the patient’s own immune system against the disease, have transformed treatment for some cancers, but not for all types and not for all patients.

T cells are one target for immunotherapies because of their central role in the immune response. These immune cells use receptors on their surface to recognize protein fragments called antigens on cancer cells. Once T cells attach to cancer antigens, they mark them for destruction by the immune system. However, T cell receptors are exceptionally diverse within one person’s immune system and from person to person, making it difficult to predict how any one cancer patient will respond to an immunotherapy.

Team MATCHMAKERS will collect data on T cell receptors and the different antigens they target and build computer models to predict antigen recognition by different T cell receptors. The team’s overarching goal is to develop tools for predicting T cell recognition with simple clinical lab tests and designing antigen-specific immunotherapies. “If successful, what we learn on our team could help transform prediction of T cell receptor recognition from something that is only possible in a few sophisticated laboratories in the world, for a few people at a time, into a routine process,” says Birnbaum.

“The MATCHMAKERS project draws on MIT’s long tradition of developing cutting-edge artificial intelligence tools for the benefit of society,” comments Ryan Schoenfeld, CEO of The Mark Foundation for Cancer Research. “Their approach to optimizing immunotherapy for cancer and many other diseases is exemplary of the type of interdisciplinary research The Mark Foundation prioritizes supporting.” In addition to The Mark Foundation, the MATCHMAKERS team is funded by Cancer Research UK and the U.S. National Cancer Institute.

Vos, the Robert A. Swanson (1969) Career Development Professor of Life Sciences and HHMI Freeman Hrabowksi Scholar in the Department of Biology, will be a co-investigator on Team KOODAC. The KOODAC team will develop new treatments for solid tumors in children, using protein degradation strategies to target previously “undruggable” drivers of cancers. KOODAC is funded by Cancer Research UK, France’s Institut National Du Cancer, and KiKa (Children Cancer Free Foundation) through Cancer Grand Challenges.

As a co-investigator on team PROSPECT, Yilmaz, who is also a Koch Institute affiliate, will help address early-onset colorectal cancers, an emerging global problem among individuals younger than 50 years. The team seeks to elucidate pathways, risk factors, and molecules involved in the disease’s development. Team PROSPECT is supported by Cancer Research UK, the U.S. National Cancer Institute, the Bowelbabe Fund for Cancer Research UK, and France’s Institut National Du Cancer through Cancer Grand Challenges.

Scientists develop a rapid gene-editing screen to find effects of cancer mutations

With the new technique, MIT researchers hope to identify mutations that could be targeted with new cancer therapies.

Anne Trafton | MIT News
March 12, 2024

Tumors can carry mutations in hundreds of different genes, and each of those genes may be mutated in different ways — some mutations simply replace one DNA nucleotide with another, while others insert or delete larger sections of DNA.

Until now, there has been no way to quickly and easily screen each of those mutations in their natural setting to see what role they may play in the development, progression, and treatment response of a tumor. Using a variant of CRISPR genome-editing known as prime editing, MIT researchers have now come up with a way to screen those mutations much more easily.

The researchers demonstrated their technique by screening cells with more than 1,000 different mutations of the tumor suppressor gene p53, all of which have been seen in cancer patients. This method, which is easier and faster than any existing approach, and edits the genome rather than introducing an artificial version of the mutant gene, revealed that some p53 mutations are more harmful than previously thought.

This technique could also be applied to many other cancer genes, the researchers say, and could eventually be used for precision medicine, to determine how an individual patient’s tumor will respond to a particular treatment.

“In one experiment, you can generate thousands of genotypes that are seen in cancer patients, and immediately test whether one or more of those genotypes are sensitive or resistant to any type of therapy that you’re interested in using,” says Francisco Sanchez-Rivera, an MIT assistant professor of biology, a member of the Koch Institute for Integrative Cancer Research, and the senior author of the study.

MIT graduate student Samuel Gould is the lead author of the paper, which appears today in Nature Biotechnology.

Editing cells

The new technique builds on research that Sanchez-Rivera began 10 years ago as an MIT graduate student. At that time, working with Tyler Jacks, the David H. Koch Professor of Biology, and then-postdoc Thales Papagiannakopoulos, Sanchez-Rivera developed a way to use CRISPR genome-editing to introduce into mice genetic mutations linked to lung cancer.

In that study, the researchers showed that they could delete genes that are often lost in lung tumor cells, and the resulting tumors were similar to naturally arising tumors with those mutations. However, this technique did not allow for the creation of point mutations (substitutions of one nucleotide for another) or insertions.

“While some cancer patients have deletions in certain genes, the vast majority of mutations that cancer patients have in their tumors also include point mutations or small insertions,” Sanchez-Rivera says.

Since then, David Liu, a professor in the Harvard University Department of Chemistry and Chemical Biology and a core institute member of the Broad Institute, has developed new CRISPR-based genome editing technologies that can generate additional types of mutations more easily. With base editing, developed in 2016, researchers can engineer point mutations, but not all possible point mutations. In 2019, Liu, who is also an author of the Nature Biotechnology study, developed a technique called prime editing, which enables any kind of point mutation to be introduced, as well as insertions and deletions.

“Prime editing in theory solves one of the major challenges with earlier forms of CRISPR-based editing, which is that it allows you to engineer virtually any type of mutation,” Sanchez-Rivera says.

When they began working on this project, Sanchez-Rivera and Gould calculated that if performed successfully, prime editing could be used to generate more than 99 percent of all small mutations seen in cancer patients.

However, to achieve that, they needed to find a way to optimize the editing efficiency of the CRISPR-based system. The prime editing guide RNAs (pegRNAs) used to direct CRISPR enzymes to cut the genome in certain spots have varying levels of efficiency, which leads to “noise” in the data from pegRNAs that simply aren’t generating the correct target mutation. The MIT team devised a way to reduce that noise by using synthetic target sites to help them calculate how efficiently each guide RNA that they tested was working.

“We can design multiple prime-editing guide RNAs with different design properties, and then we get an empirical measurement of how efficient each of those pegRNAs is. It tells us what percentage of the time each pegRNA is actually introducing the correct edit,” Gould says.

Analyzing mutations

The researchers demonstrated their technique using p53, a gene that is mutated in more than half of all cancer patients. From a dataset that includes sequencing information from more than 40,000 patients, the researchers identified more than 1,000 different mutations that can occur in p53.

“We wanted to focus on p53 because it’s the most commonly mutated gene in human cancers, but only the most frequent variants in p53 have really been deeply studied. There are many variants in p53 that remain understudied,” Gould says.

Using their new method, the researchers introduced p53 mutations in human lung adenocarcinoma cells, then measured the survival rates of these cells, allowing them to determine each mutation’s effect on cell fitness.

Among their findings, they showed that some p53 mutations promoted cell growth more than had been previously thought. These mutations, which prevent the p53 protein from forming a tetramer — an assembly of four p53 proteins — had been studied before, using a technique that involves inserting artificial copies of a mutated p53 gene into a cell.

Those studies found that these mutations did not confer any survival advantage to cancer cells. However, when the MIT team introduced those same mutations using the new prime editing technique, they found that the mutation prevented the tetramer from forming, allowing the cells to survive. Based on the studies done using overexpression of artificial p53 DNA, those mutations would have been classified as benign, while the new work shows that under more natural circumstances, they are not.

“This is a case where you could only observe these variant-induced phenotypes if you’re engineering the variants in their natural context and not with these more artificial systems,” Gould says. “This is just one example, but it speaks to a broader principle that we’re going to be able to access novel biology using these new genome-editing technologies.”

Because it is difficult to reactivate tumor suppressor genes, there are few drugs that target p53, but the researchers now plan to investigate mutations found in other cancer-linked genes, in hopes of discovering potential cancer therapies that could target those mutations. They also hope that the technique could one day enable personalized approaches to treating tumors.

“With the advent of sequencing technologies in the clinic, we’ll be able to use this genetic information to tailor therapies for patients suffering from tumors that have a defined genetic makeup,” Sanchez-Rivera says. “This approach based on prime editing has the potential to change everything.”

The research was funded, in part, by the National Institute of General Medical Sciences, an MIT School of Science Fellowship in Cancer Research, a Howard Hughes Medical Institute Hanna Gray Fellowship, the V Foundation for Cancer Research, a National Cancer Institute Cancer Center Support Grant, the Ludwig Center at MIT, a Koch Institute Frontier Award, the MIT Research Support Committee, and the Koch Institute Support (core) Grant from the National Cancer Institute.