Transplanted stem cells used to grow fully functional lungs in mice

Illustration of a human lung

According to organ donation statistics from the Health Resources & Services Administration, over 113,000 men, women, and children are on the national transplant waiting list as of July 2019. Another person is added to the waiting list every 10 minutes and 20 people die each day waiting for a transplant.

As these statistics highlight, there is a tremendous need for obtaining viable organs for people that are in need of a transplant. It is because of this, that scientists and researchers are exploring ways of using stem cells to potentially grow fully functional organs.

Dr. Hiromitsu Nakauchi, Stanford University

In a CIRM-supported study, Dr. Hiromitsu Nakauchi at Stanford University, in collaboration with Dr. Wellington Cardoso at Columbia University, were able to grow fully functional lungs in mouse embryos using transplanted stem cells. The full study, published in Nature Medicine, suggests that it may be possible to grow human lungs in animals and use them for patients in dire need of transplants or to study new lung treatments.

In the study, the researchers took stem cells and implanted them into modified mouse embryos that either lacked the stem cells necessary to form a lung or were not able to produce enough cells to make a lung. It was found that the implanted stem cells formed fully functional lungs that allowed the mice to live well into adulthood. Additionally, there were no signs of the mouse’s body rejecting the lung tissue composed of donor stem cells.

In a press release, Dr. Cardoso expressed optimism for the study and the potential the results hold:

“Millions of people worldwide who suffer from incurable lung diseases die without treatment due to the limited supply of donor lungs for transplantation. Our study shows that it may eventually be possible to develop new strategies for generating human lungs in animals for transplantation as an alternative to waiting for donor lungs.”

The challenges of living with IPEX

Last week the CIRM Board awarded $5.53 million to Dr. Rosa Bacchetta at Stanford to complete the work necessary to conduct a clinical trial for IPEX syndrome. This is a rare disease caused by mutations in the FOXP3 gene which leaves people with the condition vulnerable to immune system attacks on their organs and tissues. These attacks can be devastating, even fatal.

At the Board meeting Taylor Lookofsky, a young man with IPEX syndrome, talked about the impact the condition has had on his life. The transcript of his talk is below.

It’s a powerful reminder that syndromes like this, because they affect a small number of people, are often overlooked and have few resources devoted to finding new treatments and cures. After reading Taylor’s story you come to appreciate his courage and determination, and why the funding CIRM provides is so important in helping researchers like Dr. Bacchetta find therapies to help people like Taylor.

Brian Lookofsky (Taylor’s father), Taylor Lookofsky and Dr. Rosa Bacchetta at the CIRM Board meeting

“Good morning, my name is Taylor Lookofsky and I would first like to thank Rosa, who is one of the many doctors in my life. Rosa presented me with this amazing opportunity to come and speak to you today about my life and the challenges living with IPEX.

  • I’d like to give you some background into my health challenges I’ve faced my entire life. Now to give some context to my years of struggle, I am 28 years old, not 10 years younger as some may have assumed.
  • My first diagnosis came at the age of 1 ½ years old -type 1 diabetes.
  • Soon after being diagnosed with type 1 diabetes, I had to have a feeding tube inserted in my abdomen as I was restricted from eating almost all foods due to unknown food allergies. I was not allowed to ingest ANY food until the age of 6 years old. When I was finally introduced to food, any food ingested was tasteless and felt like sandpaper on my tongue since I had to train myself to eat.
  • Around age 10, I would be faced with the beginning of a never-ending battle with my dermatitis. I remember specific details where my mother had taken me to a dermatologist to try and figure out what was happening to my skin as it was red, blotchy, oozing. I remember shivering so badly that my mom had to ask the doctor’s office to turn the air down.
  • At age 18 I had been formally diagnosed with IPEX. I lost my hair and my skin started a battle that was more intense than any previous episode. I remember taking showers and clumps of my hair would fall out, and I would cry in the shower not knowing what was going on.
  • At age 20, I would go through the most horrific episode with my skin to date. I was bed ridden, on pain meds and could not sleep. I had gone to all of my doctors trying to figure out what had triggered this event, and no doctor could figure out what was happening, leaving me extremely frustrated, depressed and drained of all energy. I went to the burn center as a last resort and was then treated like a burn patient. To care for these wounds, I would bathe, take a sponge and physically scrape these wounds to keep them infection free and as clean as possible. When I would exit the bath, I felt like a dried-up sponge and my skin was so tight that any movement would make my skin crack open and start bleeding. To add to this, I had to use medicated wraps to help with the healing process.
  • In an ongoing attempt to treat my many symptoms, I took a series of medications that came with side effects. I have had at least 15 surgeries to remove squamous cells caused by one of the medications: In 2018, my colon perforated. As a result, I now have a colostomy bag.

The IPEX symptoms have affected me not just physically, but mentally as well. I had lost all my hair and growth has been permanently stunted, and I have not reached the point in puberty as my male counterparts. I would go day by day and see all my peers and be envious that they were tall, had beards and hair, had relationships, and the confidence that I was lacking and admittedly, still lack to this day at times.

I’ve felt hopeless because there have been so few treatment options and with the treatment currently available, I have tried hundreds of medications and creams, and have had my blood drawn countless times in hopes of finding a medication that works for me, or a cure for this insufferable disease. However, nothing. As a result, I have been battling depression singe age 20. There were days that went by where I thought “I just don’t want to be here if this is what life is going to be like.” 

The funding needed for Dr. Rosa’s therapy would be life changing in the way of new treatment options and potentially lead to a cure for this horrific disease.

I am determined to see that there is so much more to life than what society is telling me. I’ve decided that I would not conform to societies rules, and instead, tell society how I am going to live my unique and authentic life with IPEX.

I appreciate your time and consideration to fund this important research.”

Stem Cell Agency Approves Funding for Clinical Trials Targeting Parkinson’s Disease and Blindness

The governing Board of the California Institute for Regenerative Medicine (CIRM) yesterday invested $32.92 million to fund the Stem Cell Agency’s first clinical trial in Parkinson’s disease (PD), and to support three clinical trials targeting different forms of vision loss.

This brings the total number of clinical trials funded by CIRM to 60.

The PD trial will be carried out by Dr. Krystof Bankiewicz at Brain Neurotherapy Bio, Inc. He is using a gene therapy approach to promote the production of a protein called GDNF, which is best known for its ability to protect dopaminergic neurons, the kind of cell damaged by Parkinson’s. The approach seeks to increase dopamine production in the brain, alleviating PD symptoms and potentially slowing down the disease progress.

David Higgins, PhD, a CIRM Board member and patient advocate for Parkinson’s says there is a real need for new approaches to treating the disease. In the US alone, approximately 60,000 people are diagnosed with PD each year and it is expected that almost one million people will be living with the disease by 2020.

“Parkinson’s Disease is a serious unmet medical need and, for reasons we don’t fully understand, its prevalence is increasing. There’s always more outstanding research to fund than there is money to fund it. The GDNF approach represents one ‘class’ of potential therapies for Parkinson’s Disease and has the potential to address issues that are even broader than this specific therapy alone.”

The Board also approved funding for two clinical trials targeting retinitis pigmentosa (RP), a blinding eye disease that affects approximately 150,000 individuals in the US and 1.5 million people around the world. It is caused by the destruction of light-sensing cells in the back of the eye known as photoreceptors.  This leads to gradual vision loss and eventually blindness.  There are currently no effective treatments for RP.

Dr. Henry Klassen and his team at jCyte are injecting human retinal progenitor cells (hRPCs), into the vitreous cavity, a gel-filled space located in between the front and back part of the eye. The proposed mechanism of action is that hRPCs secrete neurotrophic factors that preserve, protect and even reactivate the photoreceptors, reversing the course of the disease.

CIRM has supported early development of Dr. Klassen’s approach as well as preclinical studies and two previous clinical trials.  The US Food and Drug Administration (FDA) has granted jCyte Regenerative Medicine Advanced Therapy (RMAT) designation based on the early clinical data for this severe unmet medical need, thus making the program eligible for expedited review and approval.

The other project targeting RP is led by Dr. Clive Svendsen from the Cedars-Sinai Regenerative Medicine Institute. In this approach, human neural progenitor cells (hNPCs) are transplanted to the back of the eye of RP patients. The goal is that the transplanted hNPCs will integrate and create a protective layer of cells that prevent destruction of the adjacent photoreceptors. 

The third trial focused on vision destroying diseases is led by Dr. Sophie Deng at the University of California Los Angeles (UCLA). Dr. Deng’s clinical trial addresses blinding corneal disease by targeting limbal stem cell deficiency (LSCD). Under healthy conditions, limbal stem cells (LSCs) continuously regenerate the cornea, the clear front surface of the eye that refracts light entering the eye and is responsible for the majority of the optical power. Without adequate limbal cells , inflammation, scarring, eye pain, loss of corneal clarity and gradual vision loss can occur. Dr. Deng’s team will expand the patient’s own remaining LSCs for transplantation and will use  novel diagnostic methods to assess the severity of LSCD and patient responses to treatment. This clinical trial builds upon previous CIRM-funded work, which includes early translational and late stage preclinical projects.

“CIRM funds and accelerates promising early stage research, through development and to clinical trials,” says Maria T. Millan, MD, President and CEO of CIRM. “Programs, such as those funded today, that were novel stem cell or gene therapy approaches addressing a small number of patients, often have difficulty attracting early investment and funding. CIRM’s role is to de-risk these novel regenerative medicine approaches that are based on rigorous science and have the potential to address unmet medical needs. By de-risking programs, CIRM has enabled our portfolio programs to gain significant downstream industry funding and partnership.”

CIRM Board also awarded $5.53 million to Dr. Rosa Bacchetta at Stanford to complete work necessary to conduct a clinical trial for IPEX syndrome, a rare disease caused by mutations in the FOXP3 gene. Immune cells called regulatory T Cells normally function to protect tissues from damage but in patients with IPEX syndrome, lack of functional Tregs render the body’s own tissues and organs to autoimmune attack that could be fatal in early childhood.  Current treatment options include a bone marrow transplant which is limited by available donors and graft versus host disease and immune suppressive drugs that are only partially effective. Dr. Rosa Bacchetta and her team at Stanford will use gene therapy to insert a normal version of the FOXP3 gene into the patient’s own T Cells to restore the normal function of regulatory T Cells.

The CIRM Board also approved investing $15.80 million in four awards in the Translational Research program. The goal of this program is to help promising projects complete the testing needed to begin talking to the US Food and Drug Administration (FDA) about holding a clinical trial.

The TRAN1 Awards are summarized in the table below:

ApplicationTitleInstitutionAward Amount
TRAN1 11536Ex Vivo Gene Editing of Human Hematopoietic Stem Cells for the Treatment of X-Linked Hyper IgM Syndrome  UCLA $4,896,628
TRAN1 11555BCMA/CS1 Bispecific CAR-T Cell Therapy to Prevent Antigen Escape in Multiple Myeloma  UCLA $3,176,805
TRAN1 11544 Neural Stem cell-mediated oncolytic immunotherapy for ovarian cancer  City of Hope $2,873,262
TRAN1 11611Development of a human stem cell-derived inhibitory neuron therapeutic for the treatment of chronic focal epilepsyNeurona Therapeutics$4,848,750

Rare Disease, Type 1 Diabetes, and Heart Function: Breakthroughs for Three CIRM-Funded Studies

This past week, there has been a lot of mention of CIRM funded studies that really highlight the importance of the work we support and the different disease areas we make an impact on. This includes important research related to rare disease, Type 1 Diabetes (T1D), and heart function. Below is a summary of the promising CIRM-funded studies released this past week for each one of these areas.

Rare Disease

Comparison of normal (left) and Pelizaeus-Merzbacher disease (PMD) brains (right) at age 2. 

Pelizaeus-Merzbacher disease (PMD) is a rare genetic condition affecting boys. It can be fatal before 10 years of age and symptoms of the disease include weakness and breathing difficulties. PMD is caused by a disruption in the formation of myelin, a type of insulation around nerve fibers that allows electrical signals in the brain to travel quickly. Without proper signaling, the brain has difficulty communicating with the rest of the body. Despite knowing what causes PMD, it has been difficult to understand why there is a disruption of myelin formation in the first place.

However, in a CIRM-funded study, Dr. David Rowitch, alongside a team of researchers at UCSF, Stanford, and the University of Cambridge, has been developing potential stem cell therapies to reverse or prevent myelin loss in PMD patients.

Two new studies, of which Dr. Rowitch is the primary author, published in Cell Stem Cell, and Stem Cell Reports, respectively report promising progress in using stem cells derived from patients to identify novel PMD drugs and in efforts to treat the disease by directly transplanting neural stem cells into patients’ brains. 

In a UCSF press release, Dr. Rowitch talks about the implications of his findings, stating that,

“Together these studies advance the field of stem cell medicine by showing how a drug therapy could benefit myelination and also that neural stem cell transplantation directly into the brains of boys with PMD is safe.”

Type 1 Diabetes

Viacyte, a company that is developing a treatment for Type 1 Diabetes (T1D), announced in a press release that the company presented preliminary data from a CIRM-funded clinical trial that shows promising results. T1D is an autoimmune disease in which the body’s own immune system destroys the cells in the pancreas that make insulin, a hormone that enables our bodies to break down sugar in the blood. CIRM has been funding ViaCyte from it’s very earliest days, investing more than $72 million into the company.

The study uses pancreatic precursor cells, which are derived from stem cells, and implants them into patients in an encapsulation device. The preliminary data showed that the implanted cells, when effectively engrafted, are capable of producing circulating C-peptide, a biomarker for insulin, in patients with T1D. Optimization of the procedure needs to be explored further.

“This is encouraging news,” said Dr. Maria Millan, President and CEO of CIRM. “We are very aware of the major biologic and technical challenges of an implantable cell therapy for Type 1 Diabetes, so this early biologic signal in patients is an important step for the Viacyte program.”

Heart Function

Although various genome studies have uncovered over 500 genetic variants linked to heart function, such as irregular heart rhythms and heart rate, it has been unclear exactly how they influence heart function.

In a CIRM-funded study, Dr. Kelly Frazer and her team at UCSD studied this link further by deriving heart cells from induced pluripotent stem cells. These stem cells were in turn derived from skin samples of seven family members. After conducting extensive genome-wide analysis, the team discovered that many of these genetic variations influence heart function because they affect the binding of a protein called NKX2-5.

In a press release by UCSD, Dr. Frazer elaborated on the important role this protein plays by stating that,

“NKX2-5 binds to many different places in the genome near heart genes, so it makes sense that variation in the factor itself or the DNA to which it binds would affect that function. As a result, we are finding that multiple heart-related traits can share a common mechanism — in this case, differential binding of NKX2-5 due to DNA variants.”

The full results of this study were published in Nature Genetics.

CIRM-funded Stanford study finds potential diagnostic tool, treatment for Parkinson’s

Dr. Xinnan Wang, a neurosurgeon and author of a study that has identified a molecular pathway apparently responsible for the death of dopaminergic neurons that causes the symptoms of Parkinson’s.

Of the various neurodegenerative diseases, Parkinson’s is the second most common and affects 35 million people world wide. It is caused by the gradual breakdown of dopaminergic neurons in the brain, which are a type of cell that produce a chemical in your brain known as dopamine.  This decrease in dopamine can cause complications such as uncontrollable shaking of the hands, slowed movement, rigid muscles, loss of automatic movements, speech changes, bladder problems, constipation, and sleep disorders.

Although 5-10% of cases are the result of genetically inherited mutations, the vast majority of cases are sporadic, often involving complex interactions of multiple unknown genes and environmental factors. Unfortunately, it is this unknown element that make the disease very difficult to detect early on in the majority of patients.

However, in a CIRM funded study, Dr. Xinnan Wang and her team at Stanford University were able to pinpoint a molecular defect that seems almost universal in patients with Parkinson’s and those at high risk of acquiring it. This could prove to be a way to detect Parkinson’s in its early stages and before symptoms start to manifest. Furthermore, it could also be used to evaluate a potential treatment’s effectiveness at preventing or stalling the progression of Parkinson’s.

In a Stanford press release, Dr. Wang explains the implications of these findings:

“We’ve identified a molecular marker that could allow doctors to diagnose Parkinson’s accurately, early and in a clinically practical way. This marker could be used to assess drug candidates’ capacity to counter the defect and stall the disease’s progression.” 

What is more astounding is that Dr. Wang and her team were also able to identify a compound that is shown to reverse the defect in cells taken from Parkinson’s patients. In an animal model, the compound was able to prevent the death of neurons, which is the underlying problems in the disease.

In their study, Dr. Wang and her team focused on the mitochondria, which churns out energy and is the powerhouse of the cell. Dopaminergic neurons in the brain are some of the body’s hardest working cells, and it is theorized that they start to die off when the mitochondria burns out after constant, high energy production.

Mitochondria spend much of their time attached to a grid of protein “roads” that crisscross cells. Our cells have a technique for clearing “burnt out” mitochondria, but the process involves removing an adaptor molecule called Miro that attaches mitochondria, damaged or healthy, to the grid. 

Dr. Wang’s team previously identified a mitochondrial-clearance defect in Parkinson’s patients’ cells that involved the inability to remove Miro from damaged mitochondria.

In the current study, they obtained skin samples from 83 Parkinson’s patients, Five patients with asymptomatic close relatives considered to be at heightened risk, 22 patients diagnosed with other movement disorders, and 52 healthy control subjects. They extracted fibroblasts, which are cells common in skin tissue, from the samples and subjected them to a stressful process that messes up mitochondria. 

The researchers found the Miro-removal defect in 78 of the 83 Parkinson’s fibroblasts (94%) and in all five of the “high-risk” samples, but not in fibroblasts from the control group or patients with other movement-disorders.

Next, the team was able to screen over 6.8 million molecules and found 11 that would bind to Miro, initiating separation from the mitochondria, are non-toxic, orally available, and able to cross the blood-brain barrier. These 11 compounds were tested in fruit flies and and ultimately one of them, which seems to target Miro exclusively, was tested on fibroblasts from a patient with sporadic Parkinson’s disease. The compound was found to substantially improved Miro clearance in these cells after their exposure to mitochondria-damaging stress.

Dr. Wang is optimistic that clinical trials of the compound or something similar are no more than a few years off.

In the same Stanford press release, Dr. Wang stated that,

“Our hope is that if this compound or a similar one proves nontoxic and efficacious and we can give it, like a statin drug, to people who’ve tested positive for the Miro-removal defect but don’t yet have Parkinson’s symptoms, they’ll never get it.”

The full results of this study were published in the journal Cell Metabolism.

Next generation of stem cell scientists leave their mark

One of the favorite events of the year for the team here at CIRM is our annual SPARK (Summer Program to Accelerate Regenerative Medicine Knowledge) conference. This is where high school students, who spent the summer interning at world class stem cell research facilities around California, get to show what they learned. It’s always an engaging, enlightening, and even rather humbling experience.

The students, many of whom are first generation Californians, start out knowing next to nothing about stem cells and end up talking as if they were getting ready for a PhD. Most say they went to their labs nervous about what lay ahead and half expecting to do menial tasks such as rinsing out beakers. Instead they were given a lab coat, safety glasses, stem cells and a specific project to work on. They learned how to handle complicated machinery and do complex scientific experiments.

But most importantly they learned that science is fun, fascinating, frustrating sometimes, but also fulfilling. And they learned that this could be a future career for them.

We asked all the students to blog about their experiences and the results were extraordinary. All talked about their experiences in the lab, but some went beyond and tied their internship to their own lives, their past and their hopes for the future.

Judging the blogs was a tough assignment, deciding who is the best of a great bunch wasn’t easy. But in the end, we picked three students who we thought captured the essence of the SPARK program. This week we’ll run all those blogs.

We begin with our third place blog by Dayita Biswas from UC Davis.

Personal Renaissance: A Journey from Scientific Curiosity to Confirmed Passions

By Dayita Biswas

As I poured over the pages of my battered Campbell textbook, the veritable bible for any biology student, I saw unbelievable numbers like how the human body is comprised of over 30 trillion cells! Or how we have over 220 different types of cells— contrary to my mental picture of a cell as a circle. Science, and biology in particular, has no shortage of these seemingly impossible Fermi-esque statistics that make one do a double-take. 

My experience in science had always been studying from numerous textbooks in preparation for a test or competitions, but textbooks only teach so much. The countless hours I spent reading actually demotivated me and I constantly asked myself what was the point of learning about this cycle or that process — the overwhelming “so what?” question. Those intriguing numbers that piqued my interest were quickly buried under a load of other information that made science a static stream of words across a page. 

That all changed this summer when I had the incredible opportunity to work in the Nolta lab under my mentor, Whitney Cary. This internship made science so much more tangible and fun to be a part of.  It was such an amazing environment, being in the same space with people who all have the same goals and passion for science that many high school students are not able to truly experience. Everyone was so willing to explain what they were doing, and even went out of their way to help if I needed papers or had dumb questions.

This summer, my project was to create embryoid bodies and characterize induced pluripotent stem cells (iPSCs) from children who had Jordan’s Syndrome, an extremely rare neurodevelopmental disease whose research has applications in Alzheimer’s and autism.

 I had many highs and lows during this research experience. My highs were seeing that my iPSCs were happy and healthy. I enjoyed learning lab techniques like micro-pipetting, working in a biological safety hood, feeding, freezing, and passaging cells. My lows were having to bleach my beloved iPSCs days after they failed to survive, and having unsuccessful protocols. However, while my project consistently failed, these failures taught me more than my successes.

I learned that there is a large gap between being able to read about techniques and being “book smart” and actually being able to think critically about science and perform research. Science, true science, is more than words on a page or fun facts to spout at a party. Science is never a straight or easy answer, but the mystery and difficulty is part of the reason it is so interesting. Long story short: research is hard and it takes time and patience, it involves coming in on weekends to feed cells, and staying up late at night reading papers.         

The most lasting impact that this summer research experience had was that everything we learn in school and the lab are all moving us towards the goal of helping real people. This internship renewed my passion for biology and cemented my dream of working in this field. It showed me that I don’t have to wait to be a part of dynamic science and that I can be a small part of something that will change, benefit, and save lives.

This internship meant being a part of something bigger than myself, something meaningful. We must always think critically about what consequences our actions will have because what we do as scientists and researchers— and human beings will affect the lives of real people. And that is the most important lesson anyone can hope to learn.

                                                                                                   

And here’s a bonus, a video put together by the SPARK students at Cedars-Sinai Medical Center.

Stem cell progress and promise in fighting leukemia

Computer illustration of a cancerous white blood cell in leukemia.

There is nothing you can do to prevent or reduce your risk of leukemia. That’s not a very reassuring statement considering that this year alone almost 62,000 Americans will be diagnosed with leukemia; almost 23,000 will die from the disease. That’s why CIRM is funding four clinical trials targeting leukemia, hoping to develop new approaches to treat, and even cure it.

That’s also why our next special Facebook Live “Ask the Stem Cell Team” event is focused on this issue. Join us on Thursday, August 29th from 1pm to 2pm PDT to hear a discussion about the progress in, and promise of, stem cell research for leukemia.

We have two great panelists joining us:

Dr. Crystal Mackall, has many titles including serving as the Founding Director of the Stanford Center for Cancer Cell Therapy.  She is using an innovative approach called a Chimeric Antigen Receptor (CAR) T Cell Therapy. This works by isolating a patient’s own T cells (a type of immune cell) and then genetically engineering them to recognize a protein on the surface of cancer cells, triggering their destruction. This is now being tested in a clinical trial funded by CIRM.

Natasha Fooman. To describe Natasha as a patient advocate would not do justice to her experience and expertise in fighting blood cancer and advocating on behalf of those battling the disease. For her work she has twice been named “Woman of the Year” by the Leukemia and Lymphoma Society. In 2011 she was diagnosed with a form of lymphoma that was affecting her brain. Over the years, she would battle lymphoma three times and undergo chemotherapy, radiation and eventually a bone marrow transplant. Today she is cancer free and is a key part of a CIRM team fighting blood cancer.

We hope you’ll join us to learn about the progress being made using stem cells to combat blood cancers, the challenges ahead but also the promising signs that we are advancing the field.

We also hope you’ll take an active role by posting questions on Facebook during the event, or sending us questions ahead of time to info@cirm.ca.gov. We will do our best to address as many as we can.

Here’s the link to the event, feel free to share this with anyone you think might be interested in joining us for Facebook Live “Ask the Stem Cell Team about Leukemia”

Newly discovered “don’t eat me” signal shows potential for ovarian and triple-negative breast cancer treatment

Stanford researchers have found that cancer cells have a protein called CD24 on their surface that enables them to protect themselves against the body’s immune cells.
Courtesy of Shutterstock

Getting a breast cancer diagnosis is devastating news in and of itself. Currently, there are treatment options that target three different types of receptors, which are named hormone epidermal growth factor receptor 2 (HER-2), estrogen receptors (ER), and progesterone receptors (PR), commonly found in breast cancer cells, . Unfortunately, in triple-negative breast cancer, which occurs in 10-20% of breast cancer cases, all three receptors are absent, making this form of breast cancer very aggressive and difficult to treat.

In recent years, researchers have discovered that proteins on the cell surface can tell macrophages, an immune cell designed to detect and engulf foreign or abnormal cells, not to eat and destroy them. This can be useful to help normal cells keep the immune system from attacking them, but cancer cells can also use these “don’t eat me” signals to hide from the immune system. 

An illustration of a macrophage, a vital part of the immune system, engulfing and destroying a cancer cell. Antibody 5F9 blocks a “don’t eat me” signal emitted from cancer cells. Courtesy of Forty Seven, Inc.

In fact, because of this concept, a CIRM-funded clinical trial is being conducted that uses an antibody called 5F9 to block a “don’t eat me” signal known as CD47 that is found in cancer cells. The results of this trial, which have been announced in a previous blog post, are very promising.

Further building on this concept, a CIRM-funded study has now discovered a potential new target for triple-negative breast cancer as well as ovarian cancer. Dr. Irv Weissman and a team of researchers at Stanford University have discovered an additional “don’t eat me” signal called CD24 that cancers seem to use to evade detection and destruction by the immune system.

In a press release, Dr. Weissman talks about his work with CD47 and states that,

“Finding that not all patients responded to anti-CD47 antibodies helped fuel our research at Stanford to test whether non-responder cells and patients might have alternative ‘don’t eat me’ signals.” 

The scientists began by looking for signals that were produced more highly in cancers than in the tissues from which the cancers arose. It is here that they discovered CD24 and then proceeded to implant human breast cancer cells in mice for testing. When the CD24 signaling was blocked, the mice’s immune system attacked the cancer cells.

An important discovery was that ovarian and triple-negative breast cancer were highly affected by blocking of CD24 signaling. The other interesting discovery was that the effectiveness of CD24 blockage seems to be complementary to CD47 blockage. In other words, some cancers, like blood cancers, seem to be highly susceptible to blocking CD47, but not to CD24 blockage. For other cancers, like ovarian cancer, the opposite is true. This could suggest that most cancers will be susceptible to the immune system by blocking the CD24 or CD47 signal, and that cancers may be even more vulnerable when more than one “don’t eat me” signal is blocked.

Dr. Weissman and his team are now hopeful that potential therapies to block CD24 signaling will follow in the footsteps of the clinical trials related to CD47.

The full results to the study were published in Nature.

One family’s fight to save their son’s life, and how stem cells made it possible

CIRM’s mission is very simple: to accelerate stem cell treatments to patients with unmet medical needs. Anne Klein’s son, Everett, was a poster boy for that statement. Born with a fatal immune disorder Everett faced a bleak future. But Anne and husband Brian were not about to give up. The following story is one Anne wrote for Parents magazine. It’s testament to the power of stem cells to save lives, but even more importantly to the power of love and the determination of a family to save their son.

My Son Was Born With ‘Bubble Boy’ Disease—But A Gene Therapy Trial Saved His Life

Everett Schmitt. Photo: Meg Kumin

I wish more than anything that my son Everett had not been born with severe combined immunodeficiency (SCID). But I know he is actually one of the lucky unlucky ones. By Anne Klein

As a child in the ’80s, I watched a news story about David Vetter. David was known as “the boy in the bubble” because he was born with severe combined immunodeficiency (SCID), a rare genetic disease that leaves babies with very little or no immune system. To protect him, David lived his entire life in a plastic bubble that kept him separated from a world filled with germs and illnesses that would have taken his life—likely before his first birthday.

I was struck by David’s story. It was heartbreaking and seemed so otherworldly. What would it be like to spend your childhood in an isolation chamber with family, doctors, reporters, and the world looking in on you? I found it devastating that an experimental bone marrow transplant didn’t end up saving his life; instead it led to fatal complications. His mother, Carol Ann Demaret, touched his bare hand for the first and last time when he was 12 years old.

I couldn’t have known that almost 30 years later, my own son, Everett, would be born with SCID too.

Everett’s SCID diagnosis

At birth, Everett was big, beautiful, and looked perfectly healthy. My husband Brian and I already had a 2-and-a-half-year-old son, Alden, so we were less anxious as parents when we brought Everett home. I didn’t run errands with Alden until he was at least a month old, but Everett was out and about with us within a few days of being born. After all, we thought we knew what to expect.

But two weeks after Everett’s birth, a doctor called to discuss Everett’s newborn screening test results. I listened in disbelief as he explained that Everett’s blood sample indicated he may have an immune deficiency.

“He may need a bone marrow transplant,” the doctor told me.

I was shocked. Everett’s checkup with his pediatrician just two days earlier went swimmingly. I hung up and held on to the doctor’s assurance that there was a 40 percent chance Everett’s test result was a false positive.

After five grueling days of waiting for additional test results and answers, I received the call: Everett had virtually no immune system. He needed to be quickly admitted to UCSF Benioff Children’s Hospital in California so they could keep him isolated and prepare to give him a stem cell transplant. UCSF diagnosed him specifically with SCID-X1, the same form David battled.

Beginning SCID treatment

The hospital was 90 miles and more than two hours away from home. Our family of four had to be split into two, with me staying in the hospital primarily with Everett and Brian and Alden remaining at home, except for short visits. The sudden upheaval left Alden confused, shaken, and sad. Brian and I quickly transformed into helicopter parents, neurotically focused on every imaginable contact with germs, even the mildest of which could be life-threatening to Everett.

When he was 7 weeks old, Everett received a stem cell transplant with me as his donor, but the transplant failed because my immune cells began attacking his body. Over his short life, Everett has also spent more than six months collectively in the hospital and more than three years in semi-isolation at home. He’s endured countless biopsies, ultrasounds, CT scans, infusions, blood draws, trips to the emergency department, and medical transports via ambulance or helicopter.

Gene therapy to treat SCID

At age 2, his liver almost failed and a case of pneumonia required breathing support with sedation. That’s when a doctor came into the pediatric intensive care unit and said, “When Everett gets through this, we need to do something else for him.” He recommended a gene therapy clinical trial at the National Institutes of Health (NIH) that was finally showing success in patients over age 2 whose transplants had failed. This was the first group of SCID-X1 patients to receive gene therapy using a lentiviral vector combined with a light dose of chemotherapy.

After the complications from our son’s initial stem cell transplant, Brian and I didn’t want to do another stem cell transplant using donor cells. My donor cells were at war with his body and cells from another donor could do the same. Also, the odds of Everett having a suitable donor on the bone marrow registry were extremely small since he didn’t have one as a newborn. At the NIH, he would receive a transplant with his own, perfectly matched, gene-corrected cells. They would be right at home.

Other treatment options would likely only partially restore his immunity and require him to receive infusions of donor antibodies for life, as was the case with his first transplant. Prior gene therapy trials produced similarly incomplete results and several participants developed leukemia. The NIH trial was the first one showing promise in fully restoring immunity, without a risk of cancer. Brian and I felt it was Everett’s best option. Without hesitation, we flew across the country for his treatment. Everett received the gene therapy in September 2016 when he was 3, becoming the youngest patient NIH’s clinical trial has treated.

Everett’s recovery

It’s been more than two years since Everett received gene therapy and now more than ever, he has the best hope of developing a fully functioning immune system. He just received his first vaccine to test his ability to mount a response. Now 6 years old, he’s completed kindergarten and has been to Disney World. He plays in the dirt and loves shows and movies from the ’80s (maybe some of the same ones David enjoyed).

Everett knows he has been through a lot and that his doctors “fixed his DNA,” but he’s focused largely on other things. He’s vocal when confronted with medical pain or trauma, but seems to block out the experiences shortly afterwards. It’s sad for Brian and me that Everett developed these coping skills at such a young age, but we’re so grateful he is otherwise expressive and enjoys engaging with others. Once in the middle of the night, he woke us up as he stood in the hallway, exclaiming, “I’m going back to bed, but I just want you to know that I love you with all my heart!”

I wish more than anything that Everett had not been born with such a terrible disease and I could erase all the trauma, isolation, and pain. But I know that he is actually one of the lucky unlucky ones. Everett is fortunate his disease was caught early by SCID newborn screening, which became available in California not long before his birth. Without this test, we would not have known he had SCID until he became dangerously ill. His prognosis would have been much worse, even under the care of his truly brilliant and remarkable doctors, some of whom cared for David decades earlier.

Carol-Ann-mother-of-David-Vetter-meeting-Everett-Schmitt
Everett Schmitt meeting David Vetter’s mom Carol Ann Demaret. Photo – Brian Schmitt

When Everett was 4, soon after the gene therapy gave him the immunity he desperately needed, our family was fortunate enough to cross paths with David’s mom, Carol Ann, at an Immune Deficiency Foundation event. Throughout my life, I had seen her in pictures and on television with David. In person, she was warm, gracious, and humble. When I introduced her to Everett and explained that he had SCID just like David, she looked at Everett with loving eyes and asked if she could touch him. As she touched Everett’s shoulder and they locked eyes, Brian and I looked on with profound gratitude.

Anne Klein is a parent, scientist, and a patient advocate for two gene therapy trials funded by the California Institute for Regenerative Medicine. She is passionate about helping parents of children with SCID navigate treatment options for their child.

You can read about the clinical trials we are funding for SCID here, here, here and here.

CIRM funded study identifies potential drug target for deadly heart condition

Joseph Wu is co-senior author of a study that demonstrates how patient-derived heart cells can help scientists better study the heart and screen potential therapies. Photo courtesy of Steve Fisch

Heart disease continues to be the number one cause of death in the United States. An estimated 375,000 people have a genetic form of heart disease known as familial dilated cardiomyopathy. This occurs when the heart muscle becomes weakened in one chamber in the heart, causing the open area of the chamber to become enlarged or dilated. As a result of this, the heart can no longer beat regularly, causing shortness of breath, chest pain and, in severe cases, sudden and deadly cardiac arrest.

A diagram of a normal heart compared to one with the dilated cardiomyopathy

A CIRM funded study by a team of researchers at Stanford University looked further into this form of genetic heart disease by taking a patient’s skin cells and converting them into stem cells known as induced pluripotent stem cells (iPSCs), which can become any type of cell in the body. These iPSCs were then converted into heart muscle cells that pulse just as they do in the body. These newly made heart muscle cells beat irregularly, similar to what is observed in the genetic heart condition.

Upon further analysis, the researchers linked a receptor called PGDF to cause various genes to be more highly activated in the mutated heart cells compared to normal ones. Two drugs, crenolanib and sunitinib, interfere with the PGDF receptor. After treating the abnormal heart cells, they began beating more regularly, and their gene-activation patterns more closely matched those of cells from healthy donors.

These two drugs are already FDA-approved for treating various cancers, but previous work shows that the drugs may damage the heart at high doses. The next step would be determining the right dose of the drug. The current study is part of a broader effort by the researchers to use these patient-derived cells-in-a-dish to screen for and discover new drugs.

Dr. Joseph Wu, co-senior author of this study, and his team have generated heart muscle cells from over 1,000 patients, including those of Dr. Wu, his son, and his daughter. In addition to using skin cells, the same technique to create heart cells from patients can also be done with 10 milliliters of blood — roughly two teaspoons.

In a news release, Dr. Wu is quoted as saying,

“With 10 milliliters of blood, we can make clinically usable amounts of your beating heart cells in a dish…Our postdocs have taken my blood and differentiated my pluripotent stem cells into my brain cells, heart cells and liver cells. I’m asking them to test some of the medications that I might need to take in the future.”

The full results of this study were published in Nature.