jCyte Shares Encouraging Update on Clinical Trial for Retinitis Pigmentosa

Stepping out of the darkness into light. That’s how patients are describing their experience after participating in a CIRM-funded clinical trial targeting a rare form of vision loss called retinitis pigmentosa (RP). jCyte, the company conducting the trial, announced 12 month results for its candidate stem cell-based treatment for RP.

RP is a genetic disorder that affects approximately 1 in 40,000 individuals and 1.5 million people globally. It causes the destruction of the light-sensing cells at the back of the eye called photoreceptors. Patients experience symptoms of vision loss starting in their teenage years and eventually become legally blind by middle age. While there is no cure for RP, there is hope that stem cell-based therapies could slow its progression in patients.

Photoreceptors look healthy in a normal retina (left). Cells are damaged in the retina of an RP patient (right). (Source National Eye Institute)

jCyte is one of the leaders in developing cell-based therapies for RP. The company, which was founded by UC Irvine scientists led by Dr. Henry Klassen, is testing a product called jCell, which is composed of pluripotent stem cell-derived progenitor cells that develop into photoreceptors. When transplanted into the back of the eye, they are believed to release growth factors that prevent further damage to the surviving cells in the retina. They also can integrate into the patient’s retina and develop into new photoreceptor cells to improve a patient’s vision.

Positive Results

At the Annual Ophthalmology Innovation Summit in November, jCyte announced results from its Phase 1/2a trial, which was a 12-month study testing two different doses of transplanted cells in 28 patients. The company reported a “favorable safety profile and indications of potential benefit” to patient vision.

The patients received a single injection of cells in their worst eye and their visual acuity (how well they can see) was then compared between the treated and untreated eye. Patients who received the lower dose of 0.5 million cells were able to see one extra letter on an eye chart with their treated eye compared to their untreated eye while patients that received the larger dose of 3 million cells were able to read 9 more letters. Importantly, none of the patients experienced any significant side effects from the treatment.

According to the company’s news release, “patient feedback was particularly encouraging. Many reported improved vision, including increased sensitivity to light, improved color discrimination and reading ability and better mobility. In addition, 22 of the 28 patients have been treated in their other eye as part of a follow-on extension study.”

One of these patients is Rosie Barrero. She spoke to us earlier this year about how the jCyte trial has not only improved her vision but has also given her hope. You can watch her video below.

Next Steps

These results suggest that the jCell therapy is safe (at least at the one year mark) to use in patients and that larger doses of jCell are more effective at improving vision in patients. jCyte CEO, Paul Bresge commented on the trial’s positive results:

Paul Bresge

“We are very encouraged by these results. Currently, there are no effective therapies to offer patients with RP. We are moving forward as quickly as possible to remedy that. The feedback we’ve received from trial participants has been remarkable. We look forward to moving through the regulatory process and bringing this easily-administered potential therapy to patients worldwide.”

Bresge and his company will be able to navigate jCell through the regulatory process more smoothly with the product’s recent Regenerative Medicine Advanced Therapy (RMAT) designation from the US Food and Drug Administration (FDA). The FDA grants RMAT to regenerative medicine therapies for serious diseases that have shown promise in early-stage clinical trials. The designation allows therapies to receive expedited review as they navigate their way towards commercialization.

jCyte is now evaluating the safety and efficacy of jCell in a Phase2b trial in a larger group of up to 85 patients. CIRM is also funding this trial and you can read more about it on our website.


Related Links:

 

Advertisements

A new study suggests CRISPR gene editing therapies should be customized for each patient

You know a scientific advance is a big deal when it becomes the main premise and title of a Jennifer Lopez-produced TV drama. That’s the case for CRISPR, a revolutionary gene-editing technology that promises to yield treatments for a wide range of genetic diseases.

In fact, clinical trials using the CRISPR method are already underway with more on the horizon. And at CIRM, we’re funding several CRISPR projects including a candidate gene and stem cell therapy that applies CRISPR to repair a genetic mutation found in sickle cell anemia patients.

geneeditingclip2

Animation by Todd Dubnicoff/CIRM

While these projects are moving full steam ahead, a study published this week in PNAS suggests a note of caution. They report that the natural genetic variability that is found when comparing  the DNA sequences of individuals has the potential to negatively impact the effectiveness of a CRISPR-based treatment and in some cases, could lead to dangerous side effects. As a result, the research team – a collaboration between Boston Children’s Hospital and the University of Montreal – recommends that therapy products using CRISPR should be customized to take into account the genetic variation between patients.

CRISPR 101
While other gene-editing methods pre-date CRISPR, the gene-editing technique has taken the research community by storm because of its ease of use. Pretty much any lab can incorporate it into their studies. CRISPR protein can cut specific DNA sequence within a person’s cells with the help of an attached piece of RNA. It’s pretty straight-forward to customize this “guide” RNA molecule so that it recognizes a desired DNA sequence that is in need of repair or modification.

https://player.vimeo.com/video/112757040

Because CRISPR activity heavily relies on the guide RNA molecule’s binding to a specific DNA sequence, there have been on-going concerns that a patient’s genetic variability could hamper the effectiveness of a given CRISPR therapy if it didn’t bind well. Even worse, if the genetic variability caused the CRISPR product to bind and inactivate a different region of DNA, say a gene responsible for suppressing cancer growth, it could lead to dangerous, so-called off target effects.

Although, studies have been carried out to measure the frequency of these potential CRISPR mismatches, many of the analyses depend on a reference DNA sequence from one individual. But as senior author Stuart Orkin, of Dana-Farber Boston Children’s Cancer and Blood Disorders Center, points out in a press release, this is not an ideal way to gauge CRISPR effectiveness and safety:

orkin

Stuart Orkin

“Humans vary in their DNA sequences, and what is taken as the ‘normal’ DNA sequence for reference cannot account for all these differences.”

 

 

One DNA sequence is not like the other
So, in this study, the research team analyzed previously published DNA sequence data from 7,444 people. And they focused on 30 disease genes that various researchers were targeting with CRISPR gene-editing. The team also generated 3,000 different guide RNAs with which to target those 30 disease genes.

The analysis showed that, in fact, about 50 percent of the guide RNAs could potentially have mismatches due to genetic variability found in these patients’ DNA sequences. These mismatches could lead to less effective binding of CRISPR to the disease gene target, which would reduce the effectiveness of the gene editing. And, though rare, the team also found cases in which an individual’s genetic variability could cause the CRISPR guide RNA to bind and cut in the wrong spot.

Matthew Canver, an MD-PhD student at Harvard Medical School who is also an author in the study, points out these less-than-ideal activities could also impact other gene editing techniques. Canver gives an overall recommendation how to best move forward with CRISPR-based therapy development:

canver, matthew

Matthew Canver

“The unifying theme is that all these technologies rely on identifying stretches of DNA bases very specifically. As these gene-editing therapies continue to develop and start to approach the clinic, it’s important to make sure each therapy is going to be tailored to the patient that’s going to be treated.”

 

Using the AIDS virus to help children battling a deadly immune disorder

Ronnie Kashyap, patient in SCID clinical trial: Photo Pawash Priyank

More than 35 million people around the world have been killed by HIV, the virus that causes AIDS. So, it’s hard to think that the same approach the virus uses to infect cells could also be used to help children battling a deadly immune system disorder. But that’s precisely what researchers at UC San Francisco and St. Jude Children’s Research Hospital are doing.

The disease the researchers are tackling is a form of severe combined immunodeficiency (SCID). It’s also known as ‘bubble baby’ disease because children are born without a functioning immune system and in the past were protected from germs within the sterile environment of a plastic bubble. Children with this disease often die of infections, even from a common cold, in the first two years of life.

The therapy involves taking the patient’s own blood stem cells from their bone marrow, then genetically modifying them to correct the genetic mutation that causes SCID. The patient is then given low-doses of chemotherapy to create space in their bone marrow for the news cells. The gene-corrected stem cells are then transplanted back into the infant, creating a new blood supply and a repaired immune system.

Unique delivery system

The novel part of this approach is that the researchers are using an inactivated form of HIV as a means to deliver the correct gene into the patient’s cells. It’s well known that HIV is perfectly equipped to infiltrate cells, so by taking an inactivated form – meaning it cannot infect the individual with HIV – they are able to use that infiltrating ability for good.

The results were announced at the American Society of Hematology (ASH) Annual Meeting and Exposition in Atlanta.

The researchers say seven infants treated and followed for up to 12 months, have all produced the three major immune system cell types affected by SCID. In a news release, lead author Ewelina Mamcarz, said all the babies appear to be doing very well:

“It is very exciting that we observed restoration of all three very important cell types in the immune system. This is something that’s never been done in infants and a huge advantage over prior trials. The initial results also suggest our approach is fundamentally safer than previous attempts.”

One of the infants taking part in the trial is Ronnie Kashyap. We posted a video of his story on our blog, The Stem Cellar.

If the stem cell-gene therapy combination continues to show it is both safe and effective it would be a big step forward in treating SCID. Right now, the best treatment is a bone marrow transplant, but only around 20 percent of infants with SCID have a sibling or other donor who is a good match. The other 80 percent have to rely on a less well-matched bone marrow transplant – usually from a parent – that can still leave the child prone to life-threatening infections or potentially fatal complications such as graft-versus-host disease.

CIRM is funding two other clinical trials targeting SCID. You can read about them here and here.

CIRM interviews Lorenz Studer: 2017 recipient of the Ogawa-Yamanaka Stem Cell Prize [Video]

For eight long years, researchers who were trying to develop a stem cell-based therapy for Parkinson’s disease – an incurable movement disorder marked by uncontrollable shaking, body stiffness and difficulty walking – found themselves lost in the proverbial wilderness. In initial studies, rodent stem cells were successfully coaxed to specialize into dopamine-producing nerve cells, the type that are lost in Parkinson’s disease. And further animal studies showed these cells could treat Parkinson’s like symptoms when transplanted into the brain.

Parkinsonsshutterstock_604375424

studer-lorenz

Lorenz Studer, MD
Photo Credit: Sloan Kettering

But when identical recipes were used to make human stem cell-derived dopamine nerve cells the same animal experiments didn’t work. By examining the normal developmental biology of dopamine neurons much more closely, Lorenz Studer cracked the case in 2011. Now seven years later, Dr. Studer, director of the Center for Stem Cell Biology at the Memorial-Sloan Kettering Cancer Center, and his team are on the verge of beginning clinical trials to test their Parkinson’s cell therapy in patients

It’s for these bottleneck-busting contributions to the stem cell field that Dr. Studer was awarded the Gladstone Institutes’ 2017 Ogawa-Yamanaka Stem Cell Prize. Now in its third year, the prize was founded by philanthropists Hiro and Betty Ogawa along with  Shinya Yamanaka, Gladstone researcher and director of the Center for iPS Cell Research and Application at Kyoto University, and is meant to inspire and celebrate discoveries that build upon Yamanaka’s Nobel prize winning discovery of induced pluripotent stem cells (iPSCs).

LorenzStuder_OgawaAward2017-12

(L to R) Shinya Yamanaka, Andrew Ogawa, Deepak Srivastava present Lorenz Studer the 2017 Ogawa-Yamanaka Stem Cell Prize at Gladstone Institutes. Photo Credit: Todd Dubnicoff/CIRM

Studer was honored at the Gladstone in November and presented the Ogawa-Yamanka Stem Cell Prize Lecture. He was kind enough to sit down with me for a brief video interview (watch it below) a few minutes before he took the stage. He touched upon his Parkinson’s disease research as well as newer work related to hirschsprung disease, a dangerous intestinal disorder often diagnosed at birth that is caused by the loss of nerve cells in the gut. Using human embryonic stem cells and iPSCs derived from hirschsprung patients, Studer’s team has worked out the methods for making the gut nerve cells that are lost in the disease. This accomplishment has allowed his lab to better understand the disease and to make solid progress toward a stem cell-based therapy.

His groundbreaking work has also opened up the gates for other Parkinson’s researchers to make important insights in the field. In fact, CIRM is funding several interesting early stage projects aimed at moving therapy development forward:

We posted the 8-minute video with Dr. Studer today on our official YouTube channel, CIRM TV. You can watch the video here:

And for a more detailed description of Studer’s research, watch Gladstone’s webcast recording of his entire lecture:

CIRM-Funded Research Makes Multiple Headlines this Week

When it rains it pours.

This week, multiple CIRM-funded studies appeared in the news, highlighting the exciting progress our Agency is making towards funding innovative stem cell research and promoting the development of promising stem cell therapies for patients.

Below are highlights.


Fate Therapeutics Partners with UC San Diego to Develop Cancer Immunotherapy

Last week, Dr. Dan Kaufman and his team at UC San Diego, received a $5.15 million therapeutic translational research award from CIRM to advance the clinical development of a stem cell-derived immunotherapy for acute myelogenous leukemia (AML), a rare form of blood cancer.

Today, it was announced that the UCSD team is entering into a research collaboration with a San Diego biopharmaceutical company Fate Therapeutics to develop a related immunotherapy for blood cancers. The therapy consists of immune cells called chimeric antigen receptor-targeted natural killer (CAR NK) cells that can target tumor cells and stop their growth. Fate Therapeutics has developed an induced pluripotent stem cell (iPSC) platform to develop and optimize CAR NK cell therapies targeting various cancers.

According to an article by GenBio, this new partnership is already bearing fruit.

“In preclinical studies using an ovarian cancer xenograft model, Dr. Kaufman and Fate Therapeutics had shown that a single dose of CAR-targeted NK cells derived from iPSCs engineered with the CAR construct significantly inhibited tumor growth and increased survival compared to NK cells containing a CAR construct commonly used for T-cell immunotherapy.”

 


City of Hope Brain Cancer Trial Featured as a Key Trial to Watch in 2018

Xconomy posted a series this week forecasting Key Clinical Data to look out for next year. Today’s part two of the series mentioned a recent CIRM-funded trial for glioblastoma, an aggressive, deadly brain cancer.

Christine Brown and her team at the City of Hope are developing a CAR-T cell therapy that programs a patient’s own immune cells to specifically target and kill cancer cells, including cancer stem cells, in the brain. You can read more about this therapy and the Phase 1 trial on our website.

Alex Lash, Xconomy’s National Biotech Editor, argued that good results for this trial would be a “huge step forward for CAR-T”.

Alex Lash

“While CAR-T has proven its mettle in certain blood cancers, one of the biggest medical questions in biotech is whether the killer cells can also eat up solid tumors, which make up the majority of cancer cases. Glioblastoma—an aggressive and usually incurable brain cancer—is a doozy of a solid tumor.”


ViaCyte Receives Innovative New Product Award for Type 1 Diabetes

Last week, San Diego-based ViaCyte was awarded the “Most Innovative New Product Award” by CONNECT, a start-up accelerator focused on innovation, for its PEC-Direct product candidate. The product is a cell-based therapy that’s currently being tested in a CIRM-funded clinical trial for patients with high-risk type 1 diabetes.

In a company news release published today, ViaCyte’s CEO Paul Laikind commented on what the award signifies,

Paul Laikind

“This award acknowledges how ViaCyte has continually broken new ground in stem cell research, medical device engineering, and cell therapy scaling and manufacturing. With breakthrough technology, clinical stage product candidates, an extensive intellectual property estate, and a strong and dedicated team, ViaCyte has all the pieces to advance a transformative new life-saving approach that could help hundreds of thousands of people with high-risk type 1 diabetes around the world.”

Comparing two cellular reprogramming methods from one donor’s cells yields good news for iPSCs

In 2012, a mere six years after his discovery of induced pluripotent stem cells (iPSCs), Shinya Yamanaka was awarded the Nobel Prize in Medicine. Many Nobel winners aren’t recognized until decades after their initial groundbreaking studies. That goes to show you the importance of Yamanaka’s technique, which can reprogram a person’s cells, for example skin or blood, into embryonic stem cell-like iPSCs by just adding a small set of reprogramming factors.

These iPSCs are pluripotent, meaning they can be specialized, or differentiated, into virtually any cell type in the body. With these cells in hand, researchers have a powerful tool to study human disease and to develop treatments using human cells directly from patients. And at the same time, this cell source helps avoid the ethical concerns related to embryonic stem cells.

iPSC_Wu

Induced pluripotent stem cell (iPSC) colonies.
Image Credit: Joseph Wu

Still, there has been lingering uneasiness about how well iPSCs match up to embryonic stem cells (ESCs), considered the gold-standard of pluripotent stem cells. One source of those concerns is that the iPSC method doesn’t completely reprogram cells and they retain memory of their original cell source, in the form of chemical – also called epigenetic – modifications of the cells’ DNA structure. So, if a researcher were to make, say, heart muscle cells from iPSCs that have an epigenetic memory of its skin cell origins, any resulting conclusions about a given disease study or cell therapy could be less accurate than ESC-related results. But a report published yesterday in PNAS should help relieve these worries.

The CIRM-funded study – a collaboration between the labs of Joseph Wu and Michael Synder at Stanford University and Shoukhrat Mitalipov at Oregon Health & Science University – carried out an exhaustive series of experiments that carefully compared the gene activity and cell functions of iPSC-derived cells with cells derived from embryonic stem cells. The teams sought to compare cells generated from the same person to be sure any differences were not the result of genetics. To make this “apples-to-apples” comparison, they generated embryonic stem cells using another reprogramming technique called somatic cell nuclear transfer (SCNT).

With SCNT, a nucleus from an adult cell is transferred to an egg which has its own nucleus removed. The resulting cell becomes reprogrammed back into an embryo from which embryonic stem cells are generated – the researchers call them NT-ESCs for short. In this study, the skin cell sample used for making the iPSCs and the cell nucleus used for making the NT-ESCs came from the same person. In scientific lingo, the iPSCs and SCNT stem cells are considered isogenic.

Now, it turns out the NT-ESC reprogramming process is more complete and eliminates epigenetic memory of the original cell source. So why even bother with iPSCs if you have NT-ESCs? There are big disadvantages with SCNT: it’s a complex technique – only a limited number of labs pull it off – and it requires donated human eggs which carries ethical issues. So, if a direct comparison iPSCs and SNCT stem cells shows little difference then it would be fair to argue that iPSCs can replace NT-ESCs for deriving patient-specific stem cells.

And that’s exactly what the teams found, as Dr. Wu summarized it to me in an interview:

“Direct comparison between differentiated cells derived from iPSCs and SCNT had never been performed because it had been difficult to generate patient-specific ESCs by the SCNT method. Collaborating with Dr. Shoukhrat Mitalipov at Oregon Health & Science University and Dr. Michael Snyder at Stanford University, we compared patient-specific cardiomocytes (heart muscle cells) and endothelial (blood vessel) cells derived by these two reprogramming methods (SCNT and iPSCs) and found they were relatively equivalent regarding molecular and functional features.”

PSC-ECs2 copy

Blood vessel cells derived by iPSC (left) and SCNT (right) reprogramming methods.
Image credit: Joseph Wu

Because the heart muscle and blood vessel cells were similar regardless of reprogramming method, it suggests that the epigenetic memory that remained in the iPSCs is less of a worry. Dr. Wu explained to me this way:

joewu

Joseph Wu

“If iPSCs carry substantial epigenetic memory of the cell-of-origin, it is unlikely these iPSCs can differentiate to a functional cardiac cell or blood vessel cell. Only the stem cells free of significant epigenetic memory can differentiate into functional cells.”

 

Hopefully these results hold up over time because it will bode well for the countless iPSC-related disease studies as well as the growing number of iPSC-related projects that are nearing clinical trials.

Hey, what’s the big idea? CIRM Board is putting up more than $16.4 million to find out

Higgins

David Higgins, CIRM Board member and Patient Advocate for Parkinson’s disease; Photo courtesy San Diego Union Tribune

When you have a life-changing, life-threatening disease, medical research never moves as quickly as you want to find a new treatment. Sometimes, as in the case of Parkinson’s disease, it doesn’t seem to move at all.

At our Board meeting last week David Higgins, our Board member and Patient Advocate for Parkinson’s disease, made that point as he championed one project that is taking a new approach to finding treatments for the condition. As he said in a news release:

“I’m a fourth generation Parkinson’s patient and I’m taking the same medicines that my grandmother took. They work but not for everyone and not for long. People with Parkinson’s need new treatment options and we need them now. That’s why this project is worth supporting. It has the potential to identify some promising candidates that might one day lead to new treatments.”

The project is from Zenobia Therapeutics. They were awarded $150,000 as part of our Discovery Inception program, which targets great new ideas that could have a big impact on the field of stem cell research but need some funding to help test those ideas and see if they work.

Zenobia’s idea is to generate induced pluripotent stem cells (iPSCs) that have been turned into dopaminergic neurons – the kind of brain cell that is dysfunctional in Parkinson’s disease. These iPSCs will then be used to screen hundreds of different compounds to see if any hold potential as a therapy for Parkinson’s disease. Being able to test compounds against real human brain cells, as opposed to animal models, could increase the odds of finding something effective.

Discovering a new way

The Zenobia project was one of 14 programs approved for the Discovery Inception award. You can see the others on our news release. They cover a broad array of ideas targeting a wide range of diseases from generating human airway stem cells for new approaches to respiratory disease treatments, to developing a novel drug that targets cancer stem cells.

Dr. Maria Millan, CIRM’s President and CEO, said the Stem Cell Agency supports this kind of work because we never know where the next great idea is going to come from:

“This research is critically important in advancing our knowledge of stem cells and are the foundation for future therapeutic candidates and treatments. Exploring and testing new ideas increases the chances of finding treatments for patients with unmet medical needs. Without CIRM’s support many of these projects might never get off the ground. That’s why our ability to fund research, particularly at the earliest stage, is so important to the field as a whole.”

The CIRM Board also agreed to invest $13.4 million in three projects at the Translation stage. These are programs that have shown promise in early stage research and need funding to do the work to advance to the next level of development.

  • $5.56 million to Anthony Oro at Stanford to test a stem cell therapy to help people with a form of Epidermolysis bullosa, a painful, blistering skin disease that leaves patients with wounds that won’t heal.
  • $5.15 million to Dan Kaufman at UC San Diego to produce natural killer (NK) cells from embryonic stem cells and see if they can help people with acute myelogenous leukemia (AML) who are not responding to treatment.
  • $2.7 million to Catriona Jamieson at UC San Diego to test a novel therapeutic approach targeting cancer stem cells in AML. These cells are believed to be the cause of the high relapse rate in AML and other cancers.

At CIRM we are trying to create a pipeline of projects, ones that hold out the promise of one day being able to help patients in need. That’s why we fund research from the earliest Discovery level, through Translation and ultimately, we hope into clinical trials.

The writer Victor Hugo once said:

“There is one thing stronger than all the armies in the world, and that is an idea whose time has come.”

We are in the business of finding those ideas whose time has come, and then doing all we can to help them get there.

 

 

 

Throwback Thursday: Progress towards a cure for HIV/AIDS

Welcome to our “Throwback Thursday” series on the Stem Cellar. Over the years, we’ve accumulated an arsenal of exciting stem cell stories about advances towards stem cell-based cures for serious diseases. Today we’re featuring stories about the progress of CIRM-funded research and clinical trials that are aimed at developing stem cell-based treatments for HIV/AIDS.

 Tomorrow, December 1st, is World AIDS Day. In honor of the 34 million people worldwide who are currently living with HIV, we’re dedicating our latest #ThrowbackThursday blog to the stem cell research and clinical trials our Agency is funding for HIV/AIDS.

world_logo3To jog your memory, HIV is a virus that hijacks your immune cells. If left untreated, HIV can lead to AIDS – a condition where your immune system is compromised and cannot defend your body against infection and diseases like cancer. If you want to read more background about HIV/AIDs, check out our disease fact sheet.

Stem Cell Advancements in HIV/AIDS
While patients can now manage HIV/AIDS by taking antiretroviral therapies (called HAART), these treatments only slow the progression of the disease. There is no effective cure for HIV/AIDS, making it a significant unmet medical need in the patient community.

CIRM is funding early stage research and clinical stage research projects that are developing cell based therapies to treat and hopefully one day cure people of HIV. So far, our Agency has awarded 17 grants totalling $72.9 million in funding to HIV/AIDS research. Below is a brief description of four of these exciting projects:

Discovery Stage Research
Dr. David Baltimore at the California Institute of Technology is developing an innovative stem cell-based immunotherapy that would prevent HIV infection in specific patient populations. He recently received a CIRM Quest award, (a funding initiative in our Discovery Stage Research Program) to pursue this research.

CIRM science officer, Dr. Ross Okamura, oversees Baltimore’s CIRM grant. He explained how the Baltimore team is genetically modifying the blood stem cells of patients so that they develop into immune cells (called T cells) that specifically recognize and target the HIV virus.

Ross_IDCard

Ross Okamura, PhD

“The approach Dr. Baltimore is taking in his CIRM Discovery Quest award is to engineer human immune stem cells to suppress HIV infection.  He is providing his engineered cells with T cell protein receptors that specifically target HIV and then exploring if he can reduce the viral load of HIV (the amount of virus in a specific volume) in an animal model of the human immune system. If successful, the approach could provide life-long protection from HIV infection.”

While Baltimore’s team is currently testing this strategy in mice, if all goes well, their goal is to translate this strategy into a preventative HIV therapy for people.

Clinical Trials
CIRM is currently funding three clinical trials focused on HIV/AIDS led by teams at Calimmune, City of Hope/Sangamo Biosciences and UC Davis. Rather than spelling out the details of each trial, I’ll refer you to our new Clinical Trial Dashboard (a screenshot of the dashboard is below) and to our new Blood & Immune Disorders clinical trial infographic we released in October.

dashboardblooddisorders

MonthofCIRM_BloodDisordersJustHIV.png

As you can see from these projects, CIRM is committed to funding cutting edge research in HIV/AIDS. We hope that in the next few years, some of these projects will bear fruit and help advance stem cell-based therapies to patients suffering from this disease.

I’ll leave you with a few links to other #WorldAIDSDay relevant blogs from our Stem Cellar archive and our videos that are worth checking out.

 

Second “Don’t Eat Me” Signal Identified in Cancer Cells, Points to New Immunotherapies

When the immune system comes up as a topic in everyday conversation, it’s usually related to fighting off a cold or flu. While our immune cells certainly do detect and neutralize invading bacteria and viruses, they also play a critical role in killing abnormal, cancerous cells from within our bodies.

“Don’t Eat Me” Signal 101
A white blood cell called a macrophage (macro = “big”; phage = “eater”) is part of the so-called innate immune system and acts as a first line of defense by patrolling our organs and gobbling up infected as well as cancerous cells (see macrophages in action in the cool video below).

Unfortunately, cancer cells possess the ability to cloak themselves and escape a macrophage’s engulfing grasp. Nearly all cancer cells carry a protein called CD47 on their surface. When CD47 binds to a protein called SIRPalpha on the surface of macrophages, a “don’t eat me” signal is triggered and the macrophage ignores the cancer cell.

Stanford researcher Irv Weissman and his team discovered this “don’t eat me” signal several years ago and showed that adding an antibody protein that binds tightly to CD47 interferes with the CD47/SIRPalpha signal. As a result, the anti-CD47 antibody deactivates the cancer cell’s “don’t eat me” signal and restores the macrophage’s ability to detect and kill the cancer cells.

cd47-gene3

CD47 protein on surface of cancer cells triggers “don’t eat me signal” which can be blocked with anti-CD47 antibody. Image: Acrobiosystems

Because CD47 is found on the surface of most cancer cells, this anti-CD47 antibody represents an exciting new strategy for targeting cancer stem cells – the cells thought to maintain cancer growth and cause tumor relapse – in a wide variety of cancers. In fact, CIRM has provided funding for three clinical trials, one sponsored by Stanford University and two by Forty-Seven Inc. (a company that was spun out of Stanford), that are testing anti-CD47 therapy for the treatment of the blood cancer acute myeloid leukemia (AML), as well as colon cancer and other solid tumors.

“Reaching Clinical Trials” does not equal “The Research is Done”
Although these clinical trials are underway, the Weissman team continues to seek new insights related to blocking the CD47 “don’t eat me” signal. They observed that although anti-CD47 led to increased macrophage-induced killing of most cancer cell samples tested, some were resistant to anti-CD47 and remained cloaked from macrophages. And even the cancer cells that did respond to the antibody varied widely in the amount of increased killing by macrophages.

These results suggested that alternate processes may exist that allow some cancers to evade macrophages even when the CD47 “don’t eat me” signal is blocked. In a report published this week in Nature Immunology, the researchers report the identification of a second, independent “don’t eat me” signal, which may lead to more precise methods to disarm a cancer’s evasiveness.

To track down this alternate “don’t eat me” signal, they looked for, but didn’t find, correlations between specific types of cancer cells and the cancer’s resistance to anti-CD47 treatment.  So instead they analyzed surface proteins found on the various cancer cell samples and found that cancer cells that had high levels of MHC (Major Histocompatibility Complex) class I proteins were more likely to be resistant to anti-CD47 antibodies.

A Second “Don’t Eat Me” Signal
MHC class I proteins help another arm of the immune system, the adaptive immune response, detect what’s going inside a cell. They are found on nearly all cells and display, at the cell surface, bits of proteins sampled from inside the cell. If cells of the adaptive immune response, such as T or B cells, recognize one of those protein bits as abnormal or foreign, efficient killing mechanisms are kicked into high gear to destroy those cells.

But in the case of cancers cells, the MHC class I protein are harnessed as a “don’t eat me” signal by binding to a protein called LILRB1 on macrophages. When either the MHC class I proteins or LILRB1 were blocked, the “don’t eat me” signal was lifted and restored the macrophages’ ability to kill the cancer cells both in petri dish samples as well as in mice that carried human cancers.

Graduate student and co-lead author Amira Barkal described in a press release the impact of blocking both “don’t eat me” signals at the same time:

barkalSm

Amira Barkal

“Simultaneously blocking both these pathways in mice resulted in the infiltration of the tumor with many types of immune cells and significantly promoted tumor clearance, resulting in smaller tumors overall. We are excited about the possibility of a double- or perhaps even triple-pronged therapy in humans in which we combine multiple blockades to cancer growth.”

The Big Picture for Cancer Immunotherapies
Because MHC protein class I proteins play an important role in stimulating immune cells called T cells to kill cancer cells as part of the adaptive immune response, the level of MHC protein on an individual patient’s cancer cells could serve as an indicator, or “biomarker”, for what type of cancer therapy to pursue.  The big picture implications of this idea are captured in the press release:

“Understanding the balance between adaptive and innate immunity is important in cancer immunotherapy. For example, it’s not uncommon for human cancer cells to reduce the levels of MHC class 1 on their surfaces to escape destruction by T cells. People with these types of tumors may be poor candidates for cancer immunotherapies meant to stimulate T cell activity against the cancer. But these cells may then be particularly vulnerable to anti-CD47 treatment, the researchers believe. Conversely, cancer cells with robust MHC class 1 on their surfaces may be less susceptible to anti-CD47.”

It’s time to vote for the Stem Cell Person of the Year

KnoepflerPaul14263

Paul Knoepfler

Oh well, it’s going to be another year of disappointment for me. Not only did I fail to get any Nobel Prize (I figured my blogs might give me a shot at Literature after they gave it to Bob Dylan last year), but I didn’t get a MacArthur Genius Award. Now I find out I haven’t even made the short list for the Stem Cell Person of the Year.

The Stem Cell Person of the Year award is given by UC Davis researcher, avid blogger and CIRM Grantee Paul Knoepfler. (You can vote for the Stem Cell Person of the Year here). In his blog, The Niche, Paul lists the qualities he looks for:

“The Stem Cell Person of the Year Award is an honor I give out to the person in any given year who in my view has had the most positive impact in outside-the-box ways in the stem cell and regenerative medicine field. I’m looking for creative risk-takers.”

“It’s not about who you know, but what you do to help science, medicine, and other people.”

Paul invites people to nominate worthy individuals – this year there are 20 nominees – people vote on which one of the nominees they think should win, and then Paul makes the final decision. Well, it is his blog and he is putting up the $2,000 prize money himself.

This year’s nominees are nothing if not diverse, including

  • Anthony Atala, a pioneering researcher at Wake Forest Institute for Regenerative Medicine in North Carolina
  • Bao-Ngoc Nguyen, who helped create California’s groundbreaking new law targeting clinics which offer unproven stem cell therapies
  • Judy Roberson, a tireless patient advocate, and supporter of stem cell research for Huntington’s disease

Whoever wins will be following in some big footsteps including patient advocates Ted Harada and Roman Reed, as well as scientists like Jeanne Loring, Masayo Takahashi,  and Elena Cattaneo.

So vote early, vote often.

LINK: Vote for the 2017 Stem Cell Person of the Year