Three teams empower patients’ immune systems to oust cancer

Immuno-oncology is all the rage now in biotech publications, with due cause. It is producing some pretty impressive results in patients who failed other therapies. Most of what gets written about involves strengthening or unlocking the action of one immune cell, the T cell. But our immune systems are armed with many types of ammunition; we have multiple kinds of cells that can initiate or follow through in getting rid of unwanted invaders or cancers. CIRM funds three clinical trials that test these lesser-traveled routes to juicing up our immune response to cancer.

Robert Dillman has worked to bring immune therapy to cancer patients for 25 years.

Robert Dillman has worked to bring immune therapy to cancer patients for 25 years.

While this field is hot now, it is not new. It has been elusive; researchers have tried for decades to harness our multi-talented immune system in the war on cancer. One of those researchers, Robert Dillman, who has been working on it for 25 years, now leads a CIRM-funded clinical trial in Phase 3, which is the last leg in a long journey to having a therapy approved for any patient with metastatic melanoma.

Another CIRM-funded team is also in a Phase 3 trial, in this case a therapy for the brain cancer glioblastoma developed by ImmunoCellular Therapeutics. The third CIRM-funded team at Stanford is in the middle of an early phase trial testing for safety and early signs of effectiveness with a therapy that could become an off-the-shelf therapy for many different cancers.

25-year effort getting results

Dillman now works for Caladrius Biosciences, the company conducting the Phase 3 trial in many medical centers around the U.S. He heads the clinical trial team funded by CIRM to conduct the California portion of the trial. But he has been working on the concept behind the therapy since the 1990s, most of the time at Hoag Hospital in Orange County. His mom was diagnosed with cancer when he was 14, and she died of the disease when he was an undergraduate at Stanford. His entire career has been focused on immuno-oncology.

The current effort uses a part of the immune system called dendritic cells that are derived from the patient’s blood. A patient’s tumor cells from a cell line and their dendritic cells are exposed to each other in a lab culture flask. What dendritic cells are really good at is gobbling up the cancer cells, then presenting pieces of the destroyed cancer cells to the immune cells responsible for getting rid of tumors. So, when given back to the patient the dendritic cells present the cancer bits, or antigens, like road maps to the immune cells that can then seek out and kill the cancer stem cells. The company produced a great video explaining the process.

Unlike most of the other immunotherapies that generally only present or target one CSC antigen, the Caladrius strategy presents a multitude of CSC antigens through the dendritic cells. The therapy has been associated with minimal side effects and theoretically should be more effective than other therapeutic cancer vaccine approaches. With so many specific targets, the cells are less likely to cause immune attack on healthy cells and more likely to find all the renegade tumor cells. This therapy is also a bit slower acting, which is actually a good thing. Many of the other immune therapies trigger such a strong immune response, they cause flu like symptoms that sometimes require the therapy to be halted. The dendritic cell therapy has few side effects reported so far.

Caladrius plans to conduct the trial at 32 locations, with 20 of them recruiting patients currently. The first patient was dosed in June, and a total of 250

Norm Beegun was treated in an earlier phase of the Caladrius trial.

Norm Beegun was treated in an earlier phase of the Caladrius trial.

patients will be randomly selected to get the therapy or not, with two thirds getting the therapy. The researchers plan to review the interim results as early as the end of 2017.

One patient from the earlier phase trials of the therapy, Norm Beegun, believes he definitely benefited from the treatment and told his story to our board in May.

Other approaches to ousting cancer

The CIRM-funded team at Stanford began an early phase trial in August 2014 using an antibody that blocks a receptor on the surface of CSCs called CD47. One of the researchers on the team, Irving Weissman, has dubbed that gene the “don’t eat me gene(video)” because it tells the immune system cells responsible for getting rid of tumors to not do their job. When CD47 is blocked, the immune system cells called macrophages are able to destroy—in essence eat—the CSCs.

The initial study primarily seeks to determine safety and the best dose for moving forward. It is enrolling patients with advanced-stage solid tumors. So far 12 patients have been treated with five different doses, and the team continues to screen patients for higher doses to be treated in the coming months. The trial is open only at Stanford Cancer Center under the leadership of Branimir Sikic.

The team at ImmunoCellular plans to enroll 400 brain cancer patients at 120 clinical trial sites around the U.S., Canada and Europe. They are also developing a way to turn a patient’s dendritic cells into a vaccine that helps the immune system target cancer stem cells.

One man’s story points to hope against a deadly skin cancer

At our May Board meeting a gentleman presented his story, which exemplifies being a patient and patient advocate. His name is Norm Beegun. And this is his story.

Norm Beegun was treated in an early phase of the Caladrius trial.

Norm Beegun was treated in an early phase of the Caladrius trial.

Norm lives in Los Angeles. In 2002 he went to see his regular doctor, an old high school friend, who suggested that since it had been almost ten years since he’d had a chest x-ray it might be a good idea to get one. At first Norm was reluctant. He felt fine, was having no health problems and didn’t see the need. But his friend persisted and so Norm agreed. It was a decision that changed, and ultimately saved, his life.

The x-ray showed a spot on his lung. More tests were done. They confirmed it was cancer; stage IV melanoma. They did a range of other examinations to see if they could spot any signs of the cancer on his skin, any potential warnings signs that they had missed. They found nothing.

Norm underwent surgery to remove the tumor. He also tried several other approaches to destroy the cancer. None of them worked; each time the cancer returned; each time to a different location.

Decided to try a new approach

Then a nurse who was working with him on these treatments suggested he see someone named Dr. Robert Dillman, who was working on a new approach to treating metastatic melanoma, one involving cancer stem cells.

Norm got in touch with Dr. Dillman and learned what the treatment involved; he was intrigued and signed up. They took some cells from Norm’s tumor and processed them, turning them into a vaccine, a kind of personalized therapy that would hopefully work with Norm’s own immune system to destroy the cancer.

That was in 2004. Once a month for the next six months he was given injections of the vaccine. Unlike the other therapies he had tried this one had no side effects, no discomfort, no pain or problems. All it did was get rid of the cancer. Regular scans since then have shown no sign that the melanoma has returned. Theoretically that could be because the new therapy destroyed the standard tumor cells as well as the cancer stem cells that lead to recurrence.

Didn’t miss one of son’s football games

Norm says when you are diagnosed with an incurable life-threatening disease, one with a 5-year survival rate of only around 15%, you will try anything; so he said it wasn’t a hard decision to take part in the clinical trial, he felt he had nothing to lose.

“I didn’t know if it would help me. I didn’t think I’d be cured. But I wanted to be a guinea pig and perhaps help others.”

When he was diagnosed his son had just won a scholarship to play football at the University of California, Berkeley. Norm says he feared he would never be able to see his son play. But thanks to cleverly scheduling surgery during the off-season and having a stem cell therapy that worked he not only saw his son play, he never missed a game.

Norm returned to Berkeley on May 21st, 2015. He came to address the CIRM Board in support of an application by a company called NeoStem (which has just changed its name to Caladrius Biosciences). This was the company that had developed the cell therapy for metastatic melanoma that Norm took.

“Talking about this is still very emotional. When I got up to talk to the CIRM Board about this therapy, and ask them to support it, I wanted to let them know my story, the story of someone who had their life saved by this treatment. Because of this I am here today. Because of this I was able to see my son play. But just talking about it left me close to tears.”

It left many others in the room close to tears as well. The CIRM Board voted to fund the Caladrius application, investing $17.7 million to help the company carry out a Phase 3 clinical trial, the last hurdle it needs to clear to prove to the Food and Drug Administration that this should be approved for use in metastatic melanoma.

Norm says he is so grateful for the extra years he has had, and he is always willing to try and support others going through what he did:

“I counsel other people diagnosed with metastatic melanoma. I feel that I want to help others, to give them a sense of hope. It is such a wonderful feeling, being able to show other people that you can survive this disease.”

CIRM Fights Cancer: Two teams develop therapies to stop and eliminate cancer stem cells

Six out of the ten best selling drugs are proteins called monoclonal antibodies. But the prospect for monoclonal antibodies was not always so bright. It took a decade after their discovery in 1975 before they found any clinical use, even then it was very limited use for organ transplant rejection. It was a full twenty years before their first wide spread use in cancer. One of the first cancer therapies using antibodies, Herceptin approved in 1998, keeps many breast cancer patients alive today.

UCLA's Dennis Slamon

UCLA’s Dennis Slamon

Dennis Slamon, worked for more than a decade in his lab at the University of California, Los Angeles, to get Herceptin tested, approved and marketed by Genentech. That story, told in “The Emperor of All Maladies,” shows him working against skeptics and critics often with scant financial support. Now, he has turned that laser focus on finding a therapy that can seek out and destroy cancer stem cells from a broad array of cancers—an effort he began in earnest some five years ago with an early disease team grant from CIRM.

That early CIRM grant let his team test several different compounds alone and in combination with standard therapies to settle upon one drug that targets a protein called PLK-4, a specific kinase that is found in many cancer stem cells. CIRM now funds an early phase clinical trial testing that drug in several different solid tumors. The University Health Network in Toronto, partnered with CIRM in supporting the early work, and now also funds another clinic site for the same trial at the Princess Margaret Hospital in Toronto.

All doses safe so far

So far, seven groups of patients made up of three patients each, have been given increasing doses of the drug. The Slamon team suspected that the early doses administered in the trial were likely to be too small to be effective but the Food and Drug Administration appropriately insists on the demonstration of safety first for new

Trial Patient Frank Gonzalez tells his story in his own words

Trial Patient Frank Gonzalez tells his story in his own words

therapies. So far in the study none of the groups have shown any toxicity and Slamon thinks, based on the animal data that they are now near a dose where they could see patient tumors responses. Since each group has to be monitored for four weeks before the next group can be treated it has been nearly a year since the trial began, but Herceptin showed Slamon has the stamina to stick with a therapy that makes sense.

One of the early participants in the trial, Frank Gonzalez, knew he would probably be getting a dose too low to be effective, but felt it was valuable to participate for the potential long term outcomes of the therapy. (link to his story and video)

Second trial targets leukemia stem cells

CIRM funds a second clinical trial that targets a protein broadly found on cancer stem cells, with the current trial treating leukemia. This therapy, an antibody being tested at the University of California, San Diego, targets a protein called ROR1. When the antibody blocks that protein it prevents the cancer stem cells from proliferating and encourages them to die. We at CIRM are proud of the name the team gave the antibody, Cirmtuzumab. This trial, too, was required to start at a very low dose to guarantee safety and has slowly escalated the dose with the expectation of the trial continuing for another year. One of the lead researchers on that trial, Catriona Jamieson, also thinks they may be near a therapeutic dose where they may see tumor response.

Many companies have jumped into the field developing traditional drugs and antibodies targeting cancer stem cells. As always it is nice to have colleagues working on many different routes to the same goal. It makes sense that some of these should work. Patients fearful of their doctor telling them “it’s back” deserve nothing less.

Pioneering patients heroes of early clinical trials

When Frank Gonzales was diagnosed with colorectal cancer in November 2010 it was the start of a long fight against the disease.

Chemotherapy helped keep the cancer in check, but it wasn’t a cure. So when Frank heard about a new experimental treatment, that seeks out and destroys cancer stem cells, he was intrigued.

Frank talked to UCLA’s Dr. Zev Wainberg, who is running the clinical trial funded by CIRM: “I knew it was a study and everybody wasn’t getting the same dosage but after having gone through all the other treatments this was easy.”

Frank took a single pill every day, and says he experienced no side effects. After six months he had to drop out of the trial to receive radiation.

Frank’s cancer is now in remission and he’s been able to go back to work. He doesn’t know if the pills helped but he’s proud of being a stem cell pioneer and hopes the first-in-human therapy proves effective so that one day many others will be as lucky as he is.

“It is pretty amazing. I hope they close in on it. Figure this thing out, because there’s a lot of need for it.”

CIRM fights cancer: $56 million for 5 clinical trials to vanquish tumors for good

target on CSC[This is the first of three stories on CIRM’s Cancer Fight that we will post this week. Tomorrow’s will discuss two projects that attack cancer stem cells directly and Thursday’s will describe three projects that help our immune system wipe out the traitorous cells.]

It’s back—two words we would like to remove from the cancer caregivers’ vocabulary. Many researchers blame cancer stem cells for this too common occurrence, saying cancer stem cells have ways of avoiding most traditional therapies and trigger the tumor’s return. Others prefer the term “tumor initiating cells.” But whatever you call them they need to be dealt with if we are going to make major improvements in cancer patient survival.

Cancer_stem_cellsCIRM is investing $56 million in five clinical trials targeting cancer stem cells (CSCs), the most advanced projects in our over $200 million commitment so far, to fighting cancer. Two of these trials use agents that target the cancer stem cells directly and three use agents that enable a person’s immune system to do a better job of getting rid of the CSCs.

Trials that target cancer stem cells directly

 One of the clinical trials directly targeting CSCs uses a type of protein called an antibody to seek out the renegade stem cells and initiate their demise. Antibodies home to specific proteins on the surface of cells called antigens. Researchers have been able to identify a few antigens that seem to be almost exclusively on the surface of CSCs and they have become targets for therapy.

A team at the University of California, San Diego uses an antibody named after our agency Cirmtuzumab to fight chronic lymphocytic leukemia. It targets the protein ROR1 that is abundant on CSC in the leukemia but not on normal blood-forming stem cells. Once bound on the cells Cirmtuzumab seems to prevent them from proliferating and migrating to other parts of the body and promotes them to go through a form of cell death called apoptosis.

The second trial directly attacking CSCs, at the University of California, Los Angeles, targets various solid tumors. They use a drug that affects the CSCs ability to replicate. It binds to and inhibits a protein, called a kinase, that the CSCs use when they divide.

Trials that activate the immune system

 A third clinical trial, at Stanford, also uses an antibody, but in this case it blocks a protein the CSCs use to fend off the cells in our immune system that routinely destroy emergent cancers in all of us. Immuno-oncology, the process of juicing up our immune response to cancer, is one of the hottest areas in cancer research and on Wall Street right now. But most of those efforts target a part of the immune system called the T cell. The Stanford team mobilizes a different immune cell, the macrophage, which routinely gobbles up dying, damaged or cancerous cells.

One beautiful thing about all three of these therapies is they could reverse a decade-long trend of new cancer therapies being targeted to increasingly narrow populations of cancer patients, resulting in extremely high costs per patient. Because the proteins targeted by these therapies seem to be shared across a great many types of tumors, they could be broad-spectrum cancer strategies that could be delivered at a lower cost.

CIRM currently funds five clinical trials targeting cancer stem cells.

An additional five cancer clinical trials have been undertaken based on early research funded by CIRM.

The fourth CIRM-funded clinical trial also seeks to increase our natural immune response, in this case in notoriously hard to treat metastatic melanoma. Like the Stanford team, this project by researchers at the firm Caladrius Biosciences targets a type of cell different from most immuno-oncology. In this case they derive cells called dendritic cells from the patients’ blood and establish a cell line from their tumor. In the lab they mix the cell types together and the dendritic cells gobble up the tumor cells including the cancer’s antigens, those surface proteins that act as identification tags. When re-infused into the patient the dendritic cells do what they are really good at: presenting antigens to the immune cells responsible for getting rid of tumors. Dendritic cells display the antigens like road maps to the immune cells that can then seek out and kill the cancer stem cells.

The fifth CIRM-funded trial uses a similar concept activating a patient’s dendritic cells with antigens from their brain cancers, known as glioblastomas. That trial is being conducted by ImmunoCellular Therapeutics

The first three trials are all early phase studies looking to test safety and determine what is the best dose to use going forward. The last two trials are more advanced, so-called Phase 3 studies of a dose already having shown signs of benefit in earlier trials.

Funding a clinical trial for deadly cancer is a no brainer

The beast of cancers
For a disease that is supposedly quite rare, glioblastoma seems to be awfully common. I have lost two friends to the deadly brain cancer in the last few years. Talking to colleagues and friends here at CIRM, it’s hard to find anyone who doesn’t know someone who has died of it.


Imagery of glioblastoma, a deadly brain cancer,  from ImmunoCellular’s website

So when we got an application to fund a Phase 3 clinical trial to target the cancer stem cells that help fuel glioblastoma, it was really a no brainer to say yes. Of course it helped that the scientific reviewers – our Grants Working Group or GWG – who looked at the application voted unanimously to approve it. For them, it was great science for an important cause.

Today our Board agreed with the GWG and voted to award $19.9 million to LA-based ImmunoCellular Therapeutics to carry out a clinical trial that targets glioblastoma cancer stem cells. They’re hoping to begin the trial very soon, recruiting around 400 newly diagnosed patients at some 120 clinical sites around the US, Canada and Europe.

There’s a real urgency to this work. More than 50 percent of those diagnosed with glioblastoma die within 15 months, and more than 90 percent within three years. There are no cures and no effective long-term treatments.

As our President and CEO, Dr. Randy Mills, said in a news release:

 “This kind of deadly disease is precisely why we created CIRM 2.0, our new approval process to accelerate the development of therapies for patients with unmet medical needs. People battling glioblastoma cannot afford to wait years for us to agree to fund a treatment when their survival can often be measured in just months. We wanted a process that was more responsive to the needs of patients, and that could help companies like ImmunoCellular get their potentially life-saving therapies into clinical trials as quickly as possible.”

The science
The proposed treatment involves some rather cool science. Glioblastoma stem cells can evade standard treatments like chemotherapy and cause the recurrence and growth of the tumors. The ImmunoCellular therapy addresses this issue and targets six cell surface proteins that are found on glioblastoma cancer stem cells.

The researchers take immune cells from the patient’s own immune system and expose them to fragments of these cancer stem cell surface proteins in the lab. By re-engineering the immune cells in this way they are then able to recognize the cancer stem cells.

My colleague Todd Dubnicoff likened it to letting a bloodhound sniff a piece of clothing from a burglar so it’s able to recognize the scent and hunt the burglar down.  When the newly trained immune system cells are returned to the patient’s body, they can now help “sniff out” and hopefully kill the cancer stem cells responsible for the tumor’s recurrence and growth.

Like a bloodhound picking up the scent of a burglar, ImmunoCellular's therapy helps the immune system track down brain cancer stem cells (source: wikimedia commons)

Like a bloodhound picking up the scent of a burglar, ImmunoCellular’s therapy helps the immune system track down brain cancer stem cells (source: Wikimedia Commons)

Results from both ImmunoCellular’s Phase 1 and 2 trials using this approach were encouraging, showing that patients given the therapy lived longer than those who got standard treatment and experienced only minimal side effects.

Turning the corner against glioblastoma
There’s a moment immediately after the Board votes “yes” to fund a project like this. It’s almost like a buzz, where you feel that you have just witnessed something momentous, a moment where you may have turned the corner against a deadly disease.

We have a saying at the stem cell agency: “Come to work every day as if lives depend on it, because lives depend on it.” On days like this, you feel that we’ve done something that could ultimately help save some of those lives.

Helping patient’s fight back against deadliest form of skin cancer

Caladrius Biosciences has been funded by CIRM to conduct a Phase 3 clinical trial to treat the most severe form of skin cancer: metastatic melanoma. Metastatic melanoma is a disease with no effective treatment, only around 15 percent of people with it survive five years, and every year it claims an estimated 10,000 lives in the U.S.

The CIRM/Caladrius Clinical Advisory Panel meets to chart future of clinical trial

The CIRM/Caladrius Clinical Advisory Panel meets to chart future of clinical trial

The Caladrius team has developed an innovative cancer treatment that is designed to target the cells responsible for tumor growth and spread. These are called cancer stem cells or tumor-initiating cells. Cancer stem cells can spread in the body because they have the ability to evade the body’s immune defense and survive standard anti-cancer treatments such as chemotherapy. The aim of the Caladrius treatment is to train the body’s immune system to recognize the cancer stem cells and attack them.

Attacking the cancer

The treatment process involves taking a sample of a patient’s own tumor and, in a laboratory, isolating specific cells responsible for tumor growth . Cells from the patient’s blood, called “peripheral blood monocytes,” are also collected. The mononucleocytes are responsible for helping the body’s immune system fight disease. The tumor and blood cells (after maturation into dendritic cells) are then combined and incubated so that the patient’s immune cells become trained to recognize the cancer cells.

After the incubation period, the patient’s immune cells are injected back into their body where they generate an immune response to the cancer cells. The treatment is like a vaccine because it trains the body’s immune system to recognize and rapidly attack the source of disease.

Recruiting the patients

Caladrius has already dosed the first patient in the trial (which is double blinded so no one knows if the patient got the therapy or a placebo) and hopes to recruit 250 patients altogether.

This is the first Phase 3 trial that CIRM has funded so we’re obviously excited about its potential to help people battling this deadly disease.  In a recent news release David J. Mazzo, the CEO of Caladrius echoed this excitement, with a sense of cautious optimism:

“The dosing of the first patient in this Phase 3 trial is an important milestone for our Company and the timing underscores our focus on this program and our commitment to impeccable trial execution. We are delighted by the enthusiasm and productivity of the team at Jefferson University (where the patient was dosed) and other trial sites around the country and look forward to translating that into optimized patient enrollment and a rapid completion of the Phase 3 trial.”

And that’s the key now. They have the science. They have the funding. Now they need the patients. That’s why we are all working together to help Caladrius recruit patients as quickly as possible. Because their work perfectly reflects our mission of accelerating the development of stem cell therapies for patients with unmet medical needs.

You can learn more about what the study involves and who is eligible by clicking here.

Stem cell stories that caught our eye: diabetes drug hits cancer, video stem cell tracker and quick n’ easy stem cells for fatal lung disease

The chemical structure of Metformin (Image source: WikiMedia Commons)

The chemical structure of Metformin (Image source: WikiMedia Commons)

Teaching an old drug new tricks.
One the quickest way to get a drug to market is to find one that’s already been FDA approved for other diseases. Reporting this week in Cell Metabolism, researchers from London and Madrid identified the mechanisms that enable the anti-diabetic drug, metformin, to kill pancreatic cancer stem cells (PanCSCs).

Though they make up a tiny portion of a tumor, cancer stem cells (CSCs) are thought to lie dormant most of the time. As a result, they evade chemotherapy only to later revive the tumor and cause relapse. So, the hypothesis goes, target and kill the CSCs and you’ll eradicate the cancer.


Mitochondria – a cell’s power station (image source: WikiMedia Commons)

While most cancer cells produce their energy needs without the use of oxygen, the team found that PanCSCs use oxygen-dependent energy production that occurs in a cell structure called the mitochondria. Because metformin blocks key components of the mitochondria’s energy factory, the drug essentially shuts down power to the PanCSCs leading to cell death.

The PanCSCs still have another trick up their proverbial sleeves: some switch over to a mitochondria-independent form of energy production so the metformin becomes useless against the PanCSCs. However, by tweaking the levels of two proteins, the researchers forced the PanCSCs to only use the mitochondria for energy production, which restored metformin’s cancer-killing ways.

Pancreatic cancer has very poor survival rates with very limited treatment options. Let’s hope this work leads to alternatives for patients and their doctors.

It’s all about location, location, location. Or is it?
We’ve written numerous times at the Stem Cellar about the importance of a stem cell’s “neighborhood” for determining the cell type into which it will eventually specialize. But a study published this week in Stem Cell Reports put the role of a cell’s surroundings somewhat into question.

A research team at Drexel University in Philadelphia compared stem cells in the back of the brain – an area that interprets visual information – with stem cells in the front of the brain – an area responsible for controlling movement. A fundamental question about brain development is how these areas form very different structures. Are the stem cells in each part of the brain already programmed to take on different fates or are they blank slates which rely on protein signals in the local environment to determine the type of nerve cell they become?

To chip away at this question, the team isolated mouse stem cells from the back and the front on the brain. Each set was grown in the lab using the same nutrients and conditions. You might have guessed the stem cells would behave the same but that’s not what happened. Compared to the stem cells from the back of the brain, the front brain stem cells gave rise to smaller daughter cells that divided more slowly. This suggests these brain stem cells already have some built-in properties that set them apart.

The methods used in the study are as fascinating as the results themselves. The team developed a time-lapse cell-tracking system from scratch that, with minimal human intervention, tags individual daughter cells and analyzes their fate as they grow, move and specialize on the petri dish. In the movie below, Professor Andrew Cohen, one of the authors who helped design the web-based software, succinctly describes the work. Also this movie of the tracking system in action is stunning.

Kudos to the team for making the software and their data set open access. There’s no doubt this technology will lead to important new discoveries.

Quick and easy stem cells to fight deadly lung disease
Lung disease is the 3rd deadliest disease in the U.S. It afflicts 33 million people and accounts for one in six deaths. One of those diseases is Idiopathic Pulmonary Fibrosis (IPF), an incurable disease that causes scarring and thickening of the lungs and makes breathing more and more labored. People often succumb to the disease within 3 to 5 years of their diagnosis. Use of lung stem cells to replace and heal damaged tissue is a promising therapeutic strategy for IPF.

Red and green indicate lung stem cells within a spheroid. (Image credit: Henry et al. Stem Cells Trans Med September 2015-0062)

Red and green indicate lung stem cells within a spheroid. (Image credit: Henry et al. Stem Cells Trans Med September 2015-0062)

This week, a research team from North Carolina State University reported in Stem Cells Translational Medicine on a quick and easy method for growing large amounts of lung stem cells from healthy lung tissue. The typical process of harvesting the tissue, sorting the individual lung cells, and growing the cells on petri dishes can be costly and time-consuming.

Instead, the NCSU team grew the human lung stem cells in three dimensional spheres containing multiple cell types and allowed them to float in liquid nutrients. The lung stem cells are at the center of the sphere surrounded by support cells. This method better resembles the natural cellular environment of the stem cells compared to a flat homogenous lawn of cells in a petri dish.

When introduced intravenously into mice with IPF-like symptoms, these lung spheroids reduced lung scarring and inflammation, nearly matching the animals without IPF. And in a head-to-head comparison, the lung spheroids were more effective than fat-derived mesenchymal stem cells, another proposed cell source for treating lung disease. Alas, humans are not mice and more studies are necessary to reach the ultimate goal of treating IPF patients. But I’m excited about this team’s progress and look forward to hearing more from them.

Related Press Releases:

Bye Bye BORIS: Gene Silencing Gives Cancer Stem Cells the Boot

A popular theory behind why cancer tumors recur post treatment is the existence of cancer stem cells (CSCs). These cells have stem cell-like qualities and are stubbornly resistant to common cancer cell killing techniques such as radiation and chemotherapy. CSCs are resilient and can reproduce themselves after all other cancer cells die off, creating new tumors and causing cancer relapse.


Cancer stem cells are resistant to typical cancer therapies and can cause tumor relapse.

The origin of CSCs and whether they exist in all types of cancers are questions that are still up for debate. However, it seems that the cancer field has come to a consensus that CSCs do exist in many forms of cancer, and that they are a prime target for the development of new cancer therapies. Researchers hope to develop combination therapies that target regular cancer cells and CSCs. Because what’s the use of treating tumors with drugs if they will just grow back because of pesky CSCs?

There are many proposed strategies for killing cancer stem cells. Some of them center around overcoming life-extending features that CSCs have evolved including the ability to avoid normal cell death processes. One promising technology for targeting CSCs is gene silencing. This technique uses tools that turn off the expression of specific genes (hence the silencing) that are causing cancer cells to survive or divide.

Two independent groups recently announced positive results from studies that use gene silencing technology to kill breast and colon cancer stem cells. These two stories are a great example of how pre-clinical biology from academia can translate into clinical research in industry.

On the Academic Side

A group from Lausanne University Hospital in Switzerland reported in PloS One that silencing the expression of a gene called BORIS prevented the growth of breast and colon CSCs.

BORIS inhibits the function of an important tumor suppressor gene called CTCF. A tumor suppressor gene acts as a stop sign and prevents normal cells from turning into cancer cells. When tumor suppressors can’t do their normal job due to rogue jay-walkers like BORIS, normal cells lose an important line of defense and can turn into cancer cells. Typically, BORIS is only expressed in germ cells during development and not in adult cells in the body. However, scientists have found that BORIS is reactivated in some cancer cells, typically in CSCs.

The PLoS study confirmed that BORIS was reactivated in both breast and colon CSCs. One hallmark of CSCs is their ability to survive in 3D culture systems by forming sphere-like structures. They then asked whether silencing BORIS expression in breast and colon CSCs would prevent the formation of spheres in culture. They found that without BORIS, CSCs could no longer form spheres and survive in suspension. They went on to show that when BORIS is silenced, expression of stem cell and CSC genes was reduced in both the breast and colon CSCs. The authors concluded that BORIS is an important gene for CSC survival and “could be a potential new CSC biomarker that could be used as a therapeutic target for cancer therapy.”

BORIS is expressed in breast cancer stem cells (red) but not in breast cancer cells (blue).

BORIS is expressed in breast cancer stem cells (red) but not in breast cancer cells (blue). (Alberti et al. 2015)

On the Industry Side

Regen BioPharma reported on Monday that it successfully used gene silencing technology to kill colon CSCs by silencing BORIS expression. Their positive results have prompted the company to improve and advance its gene-silencing techniques so that it can file an IND (investigational new drug) application for the BORIS gene silencing technology. An IND with the Food and Drug Administration is the final step to beginning a clinical trial in humans.

Regen has published previously in this area and acknowledged the recent findings published in PLoS. In a press release, Thomas Ichim, CSO of Regen said:

From 2006-2008, together with a team of scientists from the Institute of Molecular Medicine and the National Institutes of Health, we published that vaccinating against BORIS results in immune response against and tumor regression in breast cancer, melanoma, and glioma.  Subsequently, we published that gene silencing of BORIS can be utilized to selectively kill breast cancer cells. As we saw in the recent publication, the role of BORIS as an “Achilles Heel” of cancer is becoming more and more apparent.  We are currently in the process of advancing our gene-silencing based approaches, in part by leveraging lessons we are learning during dCellVax development, in order to file an IND for BORIS gene silencing technology.


Big Picture

the boot

Silencing BORIS gives cancer stem cells the boot. (Image source:

The issue with chemotherapies and other cancer treatments is that tumors become resistant to them over time. Gene silencing offers an advantage over these strategies by directly targeting CSCs, which are resistant to first-line cancer treatments. By silencing genes in CSCs that are required for cancer cell survival and metastasis, scientists can target tumors at their source. For patients with aggressive or recurring cancers, BORIS gene silencing technology could be what the doctor will order to prevent future relapse or metastasis. Time will tell, but hopefully gene silencing technologies against CSCs will enter clinical trials sooner than later.

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New Regenerative Liver Cells Identified

It’s common knowledge that your liver is a champion when it comes to regeneration. It’s actually one of the few internal organs in the human body that can robustly regenerate itself after injury. Other organs such as the heart and lungs do not have the same regenerative response and instead generate scar tissue to protect the injured area. Liver regeneration is very important to human health as the liver conducts many fundamental processes such as making proteins, breaking down toxic substances, and making new chemicals required to digest your food.

The human liver.

The human liver

Over the years, scientists have suggested multiple theories for why the liver has this amazing regenerative capacity. What’s known for sure is that mature hepatocytes (the main cell type in the liver) will respond to injury by dividing and proliferating to make more hepatocytes. In this way, the liver can regrow up to 70% of itself within a matter of a few weeks. Pretty amazing right?

So what is the source of these regenerative hepatocytes? It was originally thought that adult liver stem cells (called oval cells) were the source, but this theory has been disproved in the past few years. The answer to this million-dollar question, however, likely comes from a study published last week in the journal Cell.

Hybrid hepatocytes (shown in green) divide and regenerate the liver in response to injury. (Image source: Font-Burgada et al., 2015)

Hybrid hepatocytes (green) divide and regenerate the liver in response to injury. (Image source: Font-Burgada et al., 2015)

A group at UCSD led by Dr. Michael Karin reported a new population of liver cells called “hybrid hepatocytes”. These cells were discovered in an area of the healthy liver called the portal triad. Using mouse models, the CIRM-funded group found that hybrid hepatocytes respond to chemical-induced injury by massively dividing to replace damaged or lost liver tissue. When they took a closer look at these newly-identified cells, they found that hybrid hepatocytes were very similar to normal hepatocytes but differed slightly with respect to the types of liver genes that they expressed.

A common concern associated with regenerative tissue and cells is the development of cancer. Actively dividing cells in the liver can acquire genetic mutations that can cause hepatocellular carcinoma, a common form of liver cancer.

What makes this group’s discovery so exciting is that they found evidence that hybrid hepatocytes do not cause cancer in mice. They showed this by transplanting a population of hybrid hepatocytes into multiple mouse models of liver cancer. When they dissected the liver tumors from these mice, none of the transplanted hybrid cells were present. They concluded that hybrid hepatocytes are robust and efficient at regenerating the liver in response to injury, and that they are a safe and non-cancer causing source of regenerating liver cells.

Currently, liver transplantation is the only therapy for end-stage liver diseases (often caused by cirrhosis or hepatitis) and aggressive forms of liver cancer. Patients receiving liver transplants from donors have a good chance of survival, however donated livers are in short supply, and patients who actually get liver transplants have to take immunosuppressant drugs for the rest of their lives. Stem cell-derived liver tissue, either from embryonic or induced pluripotent stem cells (iPSC), has been proposed as an alternative source of transplantable liver tissue. However, safety of iPSC-derived tissue for clinical applications is still being addressed due to the potential risk of tumor formation caused by iPSCs that haven’t fully matured.

This study gives hope to the future of cell-based therapies for liver disease and avoids the current hurdles associated with iPSC-based therapy. In a press release from UCSD, Dr. Karin succinctly summarized the implications of their findings.

“Hybrid hepatocytes represent not only the most effective way to repair a diseased liver, but also the safest way to prevent fatal liver failure by cell transplantation.”

This exciting and potentially game-changing research was supported by CIRM funding. The first author, Dr. Joan Font-Burgada, was a CIRM postdoctoral scholar from 2012-2014. He reached out to CIRM regarding his publication and provided the following feedback:

CIRM Postdoctoral Fellow Jean Font-Burgada

CIRM postdoctoral scholar Joan Font-Burgada

“I’m excited to let you know that work CIRM funded through the training program will be published in Cell. I would like to express my most sincere gratitude for the opportunity I was given. I am convinced that without CIRM support, I could not have finished my project. Not only the training was excellent but the resources I was offered allowed me to work with enough independence to explore new avenues in my project that finally ended up in this publication.”


We at CIRM are always thrilled and proud to hear about these success stories. More importantly, we value feedback from our grantees on how our funding and training has supported their science and helped them achieve their goals. Our mission is to develop stem cell therapies for patients with unmet medical needs, and studies such as this one are an encouraging sign that we are making progress towards to achieving this goal.

Related links:

UCSD Press Release

CIRM Spotlight on Liver Disease Research

CIRM Spotlight on Living with Liver Disease