One-Time, Lasting Treatment for Sickle Cell Disease May be on Horizon, According to New CIRM-Funded Study

For the nearly 1,000 babies born each year in the United States with sickle cell disease, a painful and arduous road awaits them. The only cure is to find a bone marrow donor—an exceedingly rare proposition. Instead, the standard treatment for this inherited blood disorder is regular blood transfusions, with repeated hospitalizations to deal with complications of the disease. And even then, life expectancy is less than 40 years old.

In Sickle Cell Disease, the misshapen red blood cells cause painful blood clots and a host of other complications.

In Sickle Cell Disease, the misshapen red blood cells cause painful blood clots and a host of other complications.

But now, scientists at UCLA are offering up a potentially superior alternative: a new method of gene therapy that can correct the genetic mutation that causes sickle cell disease—and thus help the body on its way to generate normal, healthy blood cells for the rest of the patient’s life. The study, funded in part by CIRM and reported in the journal Blood, offers a great alternative to developing a functional cure for sickle cell disease. The UCLA team is about to begin a clinical trial with another gene therapy method, so they—and their patients—will now have two shots on goal in their effort to cure the disease.

Though sickle cell disease causes dangerous changes to a patient’s entire blood supply, it is caused by one single genetic mutation in the beta-globin gene—altering the shape of the red blood cells from round and soft to pointed and hard, thus resembling a ‘sickle’ shape for which the disease is named. But the UCLA team, led by Donald Kohn, has now developed two methods that can correct the harmful mutation. As he explained in a UCLA news release about the newest technique:

“[These results] suggest the future direction for treating genetic diseases will be by correcting the specific mutation in a patient’s genetic code. Since sickle cell disease was the first human genetic disease where we understood the fundamental gene defect, and since everyone with sickle cell has the exact same mutation in the beta-globin gene, it is a great target for this gene correction method.”

The latest gene correction technique used by the team uses special enzymes, called zinc-finger nucleases, to literally cut out and remove the harmful mutation, replacing it with a corrected version. Here, Kohn and his team collected bone marrow stem cells from individuals with sickle cell disease. These bone marrow stem cells would normally give rise to sickle-shaped red blood cells. But in this study, the team zapped them with the zinc-finger nucleases in order to correct the mutation.

Then, the researchers implanted these corrected cells into laboratory mice. Much to their amazement, the implanted cells began to replicate—into normal, healthy red blood cells.

Kohn and his team worked with Sangamo BioSciences, Inc. to design the zinc-finger nucleases that specifically targeted and cut the sickle-cell mutation. The next steps will involve improving the efficiency and safest of this method in pre-clinical animal models, before moving into clinical trials.

“This is a promising first step in showing that gene correction has the potential to help patients with sickle cell disease,” said UCLA graduate student Megan Hoban, the study’s first author. “The study data provide the foundational evidence that the method is viable.”

This isn’t the first disease for which Kohn’s team has made significant strides in gene therapy to cure blood disorders. Just last year, the team announced a promising clinical trial to cure Severe Combined Immunodeficiency Syndrome, also known as SCID or “Bubble Baby Disease,” by correcting the genetic mutation that causes it.

While this current study still requires more research before moving into clinical trials, Kohn and his team announced last month that their other gene therapy method, also funded by CIRM, has been approved to start clinical trials. Kohn argues that it’s vital to explore all promising treatment options for this devastating condition:

“Finding varied ways to conduct stem cell gene therapies is important because not every treatment will work for every patient. Both methods could end up being viable approaches to providing one-time, lasting treatments for sickle cell disease and could also be applied to the treatment of a large number of other genetic diseases.”

Find Out More:
Read first-hand about Sickle Cell Disease in our Stories of Hope series.
Watch Donald Kohn speak to CIRM’s governing Board about his research.

Stem cell stories that caught our eye; viral genes in embryos, underuse of transplants and joint pain clinics

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Ancient viral invaders help make us, us. The cells of our ancestors millions of years ago may have found a way to turn viral invasion into a good thing. This genetic lemons-to-lemonade tale comes from a team in Singapore that meticulously looked at 650,000 bits of virus genes that have been left behind in our cells after viral infections.

Retroviruses like HIV can only replicate by integrating their genes into ours and getting our cellular machinery to make new copies of themselves. Biologists have long known that they often leave behind bits of their genes, but had assumed this became part of the “junk DNA” that does not serve any function and that makes up the bulk of the genetic material in our cells. That scenario has started to change over the past few years as teams have reported examples of those retroviral genetic elements playing a role in the regulation—the turning on and off—of our functional genes.
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Jonathan Goke, the lead researcher on the project at the Genome Institute of Singapore, wrote that roughly 1,400 of those viral gene elements were involved in the very early stages of embryo development, helping determine how cells decide to mature into different types of tissue. They seem to be needed for determining who we are.

In an article on the website science 2.0 Goke speculated that these viruses may have been able to speed-up evolution by making changes in gene function faster than random mutation.

Blood stem cell transplants under used. Even as the number of blood stem cell transplants ever performed has passed the one million mark, a new report warns that lives are at risk because too many patients that could benefit are not getting these transplants. Blood stem cell transplants, which started as bone marrow transplants, provide the only shot at life-saving therapy for many patients, mostly those with blood cancers.

An international team, led by Dietger Niederwieser of the University Hospital Leipzig in Germany, found a dramatic under use of donor cells for transplants that varied widely around the world. Writing in the Lancet they reported that just 0.4 people per 10 million in the Philippines get such transplants, but in Israel the number shoots up to 506. The report noted both uneven distribution of resources needed to perform the complex procedure and inconsistent support for and participation in donor registries. Niederwieser was quoted in a press release from the journal picked up by ScienceDaily:

“Patients, many of them children, are facing a life and death situation. Ultimately they will die if they cannot get the treatment they need. All countries need to provide adequate infrastructure for patients and donors to make sure that everyone who needs a transplant gets one, rather than the present situation in which access remains restricted to countries and people with sufficient resources.”

What is real with stem cells and joint pain? Bethesda Magazine, the local publication for the county that is home to the National Institutes of Health (NIH), produced a good piece giving the perspective of patients wanting to avoid joint replacement surgery as well as scientists leery of cell-based procedures that have very little evidence to back them up.

The magazine reached out to its neighbor, the NIH to provide some perspective. It quotes Pamela Robey, the co-coordinator of the NIH Bone Marrow Stromal Cell Transplantation Center—those stromal cells are one type of cell often touted by clinics offering to treat joint pain.

“There are a huge number of clinical trials, but there has been next to no published information. The bottom line is there’s no real rigorous data showing it is actually repairing the joint.”

The author also talked to CIRM grantee Larry Goldstein of the University of California, San Diego, in his role as a member of the Ethics and Public Policy Committee of the International Society for Stem Cell Research. He notes that what clinics are offering is unproven and the author directs readers to the ISSCR web site’s “Closer Look” section to get more information on how to evaluate potential therapies they may be considering.

Stay on Target: Scientists Create Chemical ‘Homing Devices’ that Guide Stem Cells to Final Destination

When injecting stem cells into a patient, how do the cells know where to go? How do they know to travel to a specific damage site, without getting distracted along the way?

Scientists are now discovering that, in some cases they do but in many cases, they don’t. So engineers have found a way to give stem cells a little help.

As reported in today’s Cell Reports, engineers at Brigham and Women’s Hospital (BWH) in Boston, along with scientists at the pharmaceutical company Sanofi, have identified a suite of chemical compounds that can help the stem cells find their way.

Researchers identified a small molecule that can be used to program stem cells (blue and green) to home in on sites of damage. [Credit: Oren Levy, Brigham and Women's Hospital]

Researchers identified a small molecule that can be used to program stem cells (blue and green) to home in on sites of damage. [Credit: Oren Levy, Brigham and Women’s Hospital]

“There are all kinds of techniques and tools that can be used to manipulate cells outside the body and get them into almost anything we want, but once we transplant cells we lose complete control over them,” said Jeff Karp, the paper’s co-senior author, in a news release, highlighting just how difficult it is to make sure the stem cells reach their destination.

So, Karp and his team—in collaboration with Sanofi—began to screen thousands of chemical compounds, known as small molecules, that they could physically attach to the stem cells prior to injection and that could guide the cells to the appropriate site of damage. Not unlike a molecular ‘GPS.’

Starting with more than 9,000 compounds, the Sanofi team narrowed down the candidates to just six. They then used a microfluidic device—a microscope slide with tiny glass channels designed to mimic human blood vessels. Stem cells pretreated with the compound Ro-31-8425 (one of the most promising of the six) stuck to the sides. An indication, says the team, Ro-31-8425 might help stem cells home in on their target.

But how would these pre-treated cells fare in animal models? To find out, Karp enlisted the help of Charles Lin, an expert in optical imaging at Massachusetts General Hospital. First, the team injected the pre-treated cells into mouse models each containing an inflamed ear. Then, using Lin’s optical imaging techniques, they tracked the cells’ journey. Much to their excitement, the cells went immediately to the site of inflammation—and then they began to repair the damage.

According to Oren Levy, the study’s co-first author, these results are especially encouraging because they point to how doctors may someday soon deliver much-needed stem cell therapies to patients:

“There’s a great need to develop strategies that improve the clinical impact of cell-based therapies. If you can create an engineering strategy that is safe, cost effective and simple to apply, that’s exactly what we need to achieve the promise of cell-based therapy.”

Shape-Shifting Pancreas Cells Set Stage for Development of Deadly Cancer

After being diagnosed with pancreatic cancer, the likely outcome is—in a word—bleak. At a time when cancers can be treated so successfully as to give the patient a good quality of life, pancreatic cancer remains one of the last holdouts. It is the fourth most deadly form of cancer in the United States. One in four patients won’t last a year.

Pancreatic cancer is one of the most deadly forms of cancer.

Pancreatic cancer is one of the most deadly forms of cancer.

One of the main hurdles for successfully treating this type of cancer is how quickly it spreads. Oftentimes, pancreatic cancer is not diagnosed until having spread to such an extent that even the most aggressive treatments can only delay the inevitable.

As a result, the goal of researchers has been to peer back in time to the origins of pancreatic cancer—in the hopes that they can find a way to halt the disease before it begins to wreak irreversible damage on the body. And now, an international team of researchers believes they have identified a gene that could be the key culprit.

Reporting in the latest issue of Nature Communications, a joint team of scientists from the Mayo Clinic and the University of Oslo, Norway, have pinpointed a gene—called PKD1—that causes normal, healthy pancreatic cells to literally morph into a new, duct-like cell structure. And it is this change in shape that can sometimes lead to pancreatic cancer.

“As soon as pancreatic cancer develops, it begins to spread, and PKD1 is key to both processes,” said Peter Storz, one of the study’s lead authors, in a news release. “Given this finding, we are busy developing a PKD1 inhibitor that we can test further.”

The purpose of the inhibitor, says Storz, is to neutralize PKD1—stopping the cancer in its tracks.

Using pancreatic cells derived from mouse models, the research team tested the effects of PKD1 by turning it on and off at specific intervals, similar to flipping a light switch. In the presence of PKD1, the team observed the pancreas cells rapidly changing shape into the more dangerous, duct-like cells. And when they shut off PKD1, the percentage of cells that underwent shape shifting dropped.

The team’s success at developing this model cannot be understated. As Storz explained:

“This model tells us that PKD1 is essential for the initial transformation…to duct-like cells, which can then become cancerous. If we can stop that transformation from happening—or perhaps reverse the process once it occurs—we may be able to block or treat cancer development and its spread.”

Currently, the teams are developing potential PDK1 inhibitors for further testing—and bring some hope that the prognosis for pancreatic cancer may not always be so dire.

Said Storz: “While these are early days, understanding one of the key drivers in this aggressive cancer is a major step in the right direction.”

Stem cell stories that caught our eye; progress toward artificial brain, teeth may help the blind and obesity

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

More progress toward artificial brain. A team at the RIKEN Institute in Japan has used stem cells in a 3-D culture to create brain tissue more complex than prior efforts and from an area of the brain not produced before, the cerebellum—that lobe at the lower back of the brain that controls motor function and attention. As far back as 2008, a RIKEN team had created simple tissue that mimicked the cortex, the large surface area that controls memory and language.

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The Inquisitr web portal wrote a feature on a wide variety of efforts to create an artificial brain teeing off of this week’s publication of the cerebellum work in Cell Reports. The piece is fairly comprehensive covering computerized efforts to give robots intelligence and Europe’s Human Brain Project that is trying to map all the activity of the brain as a starting point for recapitulating it in the lab.

The experts interviewed included Robert Caplan of Tufts University in Massachusetts who is using 3-D scaffolding to build functional brain tissues that can process electrical signals. He is not planning any Frankenstein moments; he hopes to create models to improve understanding of brain diseases.

“Ideally we would like to have a laboratory brain system that recapitulates the most devastating diseases. We want to be able to take our existing toolkit of drugs and understand how they work instead of using trial and error.”

Teeth eyed as source of help for the blind. Today the European Union announced the first approval of a stem cell therapy for blindness. And already yesterday a team at the University of Pittsburg announced they had developed a new method to use stem cells to restore vision that could expand the number of patients who could benefit from stem cell therapy.

Many people have lost part or all their vision due to damage to the cornea on the surface of their eye. Even when they can gain vision back through a corneal transplant, their immune system often rejects the new tissue. So the ideal would be making new corneal tissue from the patient’s own cells. The Italian company that garnered the EU approval does this in patients by harvesting some of their own cornea-specific stem cells, called limbal stem cells. But this is only an option if only one eye is impacted by the damage.

The Pittsburgh team thinks it may have found an unlikely alternative source of limbal cells: the dental pulp taken from teeth that have be extracted. It is not as far fetched at it sounds on the surface. Teeth and the cornea both develop in the same section of the embryo, the cranial neural crest. So, they have a common lineage.

The researchers first treated the pulp cells with a solution that makes them turn into the type of cells found in the cornea. Then they created a fiber scaffold shaped like a cornea and seeded the cells on it. Many steps remain before people give up a tooth to regain their sight, but this first milestone points the way and was described in a press release from the journal Stem Cells Translational Medicine, which was picked up by the web site ClinicaSpace.

CIRM funds a project that also proposes to use the patient’s own limbal stem cells but using methods more likely to gain approval of the Food and Drug Administration than those used by the Italian company.

Stem cells and the fight against obesity. Of the two types of stem cells found in your bone marrow, one can form bone and cartilage and, all too often, fat. Preventing these stem cells from maturing into fat may be a tool in the fight against obesity according to a team at Queen Mary University of London.

The conversion of stem cells to fat seems to involve the cilia, or hair-like projections found on cells. When the cilia lengthen the stem cells progress toward becoming fat. But if the researchers genetically prevented that lengthening, they stopped the conversion to fat cells. The findings opens several different ways to think about understanding and curbing obesity says Melis Dalbay one of the authors of the study in a university press release picked up by ScienceNewsline.

“This is the first time that it has been shown that subtle changes in primary cilia structure can influence the differentiation of stem cells into fat. Since primary cilia length can be influenced by various factors including pharmaceuticals, inflammation and even mechanical forces, this study provides new insight into the regulation of fat cell formation and obesity.”

Clearing up chemobrain: cancer therapy-induced memory problems reversed by stem cells

You’d think receiving a cancer diagnosis and then suffering through chemo and/or radiation therapy would be traumatic enough. But as many as 75% of cancer survivors are afflicted by memory and attention problems long after their cancer therapy.

This condition, often called “chemobrain”, shouldn’t be misunderstood as being confined to cancers of the brain. A 2012 analysis of nearly 200 women who had been treated with chemotherapy for breast cancer showed they had ongoing memory and information processing deficits that persisted more than twenty years after their last round of treatment. And young cancer survivors are particularly vulnerable to reduced IQs, nonsocial behavior and an extremely lowered quality of life.

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CIRM grantee and UC Irvine professor Charles Limoli, PhD is senior author of this study

Chemotherapy drugs work by killing off cells that are dividing rapidly, a hallmark of cancer cells. But this brute force method also kills other rapidly dividing cells that are critical for normal bodily functions. In the case of chemobrain, it’s thought that damage to newly formed brain cells in the hippocampus, the memory center of the brain, is the culprit. A UC Irvine study published this week in Cancer Research supports that idea in experiments that test the effect of transplanting human nerve stem cells in rats. The research team leader Charles Limoli, a CIRM grantee and UC Irvine professor of radiation oncology, summarized the groundbreaking results in a press release (note: this study is not funded by CIRM):

“Our findings provide the first solid evidence that transplantation of human neural stem cells can be used to reverse chemotherapeutic-induced damage of healthy tissue in the brain.”

The novel place recognition test is evaluate memory function. Animal is initially presented with identical objects (red circles). Then a new object is introduced (blue square). A healthy mouse will investigate the blue square.

The novel place recognition test, one of several tests used in this study to evaluate memory function.  During training setup (left), the rodent is familiarized with identical objects (red circles). Later, rodent returns now in presence of a new object (blue square). A healthy mouse will investigate the new object during testing setup (right). Image credit: KnowingNeurons.com

So how the heck do you observe chemotherapy-induced cognitive problems in a rodent let alone show that stem cells can rescue the damage? In the study, the rats undergo a variety of recognition memory tasks after a typical chemotherapy drug treatment. For instance, in the novel place recognition test, an animal is familiarized with two identical objects inside a test “arena”. Later, the animal is returned to the arena but a new object is swapped in for one of the previous objects. Rats given chemotherapy treatment but no stem cell surgery (they’re implanted with a saline solution instead) do not show a preference for the novel object. But rats given chemotherapy and the human nerve stem cell surgery prefer the novel object. This novel seeking behavior is also seen in control rats given no chemotherapy. So these results demonstrate that the transplanted stem cells rescued normal memory recognition in the chemotherapy-treated rats.

The research team also saw differences within the brains of these groups of rats that match up with these behavioral results. First, they confirmed that the transplanted human stem cells had indeed survived and grafted into the rat brains and had matured into the correct type of brain cells. Next they looked at chemotherapy-induced inflammation of brain tissue. The brains of chemotherapy-treated rats with no stem cell transplantation showed increased number of active immune cells compared to the control and stem cell transplanted animals. In another experiment, a detailed analysis of the structure of individual nerve cells showed extensive damage in the chemotherapy treated rats compared to controls. Again, this damage was reversed in chemotherapy treated rats that also received the stem cell transplant.

Rat nerve cells (black structures) in memory center of the brain are damaged by chemotherapy (left); transplanting human nerve stem cells reverses the damage (right)

Rat nerve cells (black structures) in memory center of the brain are damaged by chemotherapy (left); transplanting human nerve stem cells reverses the damage (right). Image credit: Acharya et al. Cancer Research 75(4) p. 676

As many researchers can tell you, these exciting results in animals don’t guarantee a human therapy is around the corner. But still, says Limoli:

“This research suggests that stem cell therapies may one day be implemented in the clinic to provide relief to patients suffering from cognitive impairments incurred as a result of their cancer treatments. While much work remains, a clinical trial analyzing the safety of such approaches may be possible within a few years.”

For a more details about the role of stem cells in chemobrain, watch this recent presentation to the CIRM Governing Board by CIRM grantee and Stanford professor Michelle Monje.

Stem cell stories that caught our eye: Cancer genetics, cell fate, super donors and tale of road to diabetes cure

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

For cancer growth timing is everything. A study originating at the University of Southern California suggests tumors are born to be bad. Mutations constantly occur during the life of a tumor but those that occur early on determine if a tumor will grow as a benign mass of a cancerous one that spreads.

Describing the genetic markers the team found, the senior author, Christina Curtis, who recently moved to Stanford, was quoted in a story in ScienceBlog:

“What you see in the final cancer was there from the beginning.”

The CIRM funded team completed detailed genetic analysis of tumor cells surgically removed from colon cancer patients. Doctors treating these patients have long been hampered by an inability to tell which tumors will remain small and benign and which will develop into full-blown cancer. The researchers suggest the genetic fingerprints they have uncovered could lead to improved diagnosis for patients.

Physical forces also key to cell fate.
Putting the squeeze on stem cells may be what’s needed to get them to become bone. In this case, a team at the University of California, San Diego, used teeny tiny tweezers called “optical tweezers,” to trigger key internal signals that directed stem cells to go down the path to bone.

Pressure results in release of a cell signal shown in red

Pressure results in release of a cell signal shown in red

We have frequently written about the tremendous importance of a stem cell’s environment—its neighborhood if you will—in determining its fate. Yingxiao Wang, who led the study, described this role in a press release from the university picked up by ScienceNewsline:

“The mechanical environment around a stem cell helps govern a stem cell’s fate. Cells surrounded in stiff tissue such as the jaw, for example, have higher amounts of tension applied to them, and they can promote the production of harder tissues such as bone.”

He said the findings should help researchers trying to replicate the natural stem cell environment in the lab when they try to grow replacement tissues for patients.

Super donors could provide matching tissue.
One of the biggest challenges of using stem cells to replace damaged tissue is avoiding immune system rejection of the new cells. CIRM-grantee Cellular Dynamics International (CDI) announced this week that they have made key initial steps to creating a cell bank that could make this much easier.

Our bodies use molecules on the surface of our cells to identify tissue that is ours versus foreign such as bacteria. The huge variation in those molecules, called HLA, makes the matching needed for donor organ, or donor cells, more difficult than the New York Times Sunday crossword. But a few individuals posses an HLA combination that allows them to match to a large percent of the population.

CDI has now created clinical grade stem cell lines using iPS reprogramming of adult tissue from two such “super donors.” Just those two cell lines provide genetic matches for 19 percent of the population. The company plans to develop additional lines from other super donors with the goal of creating a bank that would cover 95 percent of the population.

Reuters picked up the company’s press release. CIRM does not fund this project, but we do fund another cell bank for which CDI is creating cells to better understand the causes of 11 diseases that have complex genetic origins

Narrative tells the tale of developing diabetes therapy. MIT Technology Review has published a well-told feature about the long road to creating a stem cell-based therapy for diabetes. Author Bran Alexander starts with the early days of the “stem cell wars” and carries the tale through treatment of the first patients in the CIRM-funded clinical trial being carried out by ViaCyte and the University of California, San Diego.

The piece quotes Viacyte’s chief scientific officer Kevin D’Amour about the long road:

“When I first came to ViaCyte 12 years ago, cell replacement through stem cells was so obvious. We all said, ‘Oh, that’s the low-hanging fruit.’ But it turned out to be a coconut, not an apple.”

But the article shows that with Viacyte’s product as well as others coming down the pike, that coconut has been cracked and real hope for diabetics lies inside.

Combination Cancer Therapy Gives Cells a Knockout Punch

For some forms of cancer, there really is no way to truly eradicate it. Even the most advanced chemotherapy treatments leave behind some straggler cells that can fuel a relapse.

By hitting breast cancer cells with a targeted therapeutic immediately after chemotherapy, researchers were able to target cancer cells during a transitional stage when they were most vulnerable. [Credit: Aaron Goldman]

By hitting breast cancer cells with a targeted therapeutic immediately after chemotherapy, researchers were able to target cancer cells during a transitional stage when they were most vulnerable.
[Credit: Aaron Goldman]

But now, scientists have devised a unique strategy, something they are calling a ‘one-two punch’ that can more effectively wipe out dangerous tumors, and lower the risk of them ever returning for a round two.

Reporting in the latest issue of the journal Nature Communications, bioengineers at Brigham and Women’s Hospital (BWH) in Boston describe how treating breast cancer cells with a targeted drug immediately after chemotherapy was effective at killing the cancer cells and preventing a recurrence. According to lead scientist Shiladitya Sengupta, these findings were wholly unexpected:

“We were studying the fundamentals of how [drug] resistance develops and looking to understand what drives [cancer] relapse. What we found is a new paradigm for thinking about chemotherapy.”

In recent years, many scientists have suggested cancer stem cells are one of the biggest hurdles to curing cancer. Cancer stem cells are proposed to be a subpopulation of cancer cells that are resistant to chemotherapy. As a result, they can propagate the cancer after treatment, leading to a relapse.

In this work, Sengupta and his colleagues treated breast cancer cells with chemotherapy. And here is where things started getting interesting.

After chemotherapy, the breast cancer cells began to morph into cells that bore a close resemblance to cancer stem cells. For a brief period of time after treatment, these cells were neither fully cancer cells, nor fully stem cells. They were in transition.

The team then realized that because these cells were in transition, they may be more vulnerable to attack. Testing this hypothesis in mouse models of breast cancer, the team first zapped the tumors with chemotherapy. And, once the cells began to morph, they then blasted them with a different type of drug. The tumors never grew back, and the mice survived.

Interestingly, the team did not have similar success when they altered the timing of when they administered the therapy. Treating the mice with both types of drugs simultaneously didn’t have the same effect. Neither did increasing the time between treatments. In order to successfully treat the tumor they had a very slim window of opportunity.

“By treating with chemotherapy, we’re driving cells through a transition state and creating vulnerabilities,” said Aaron Goldman, the study’s first author. “This opens up the door: we can then try out different combinations and regimens to find the most effective way to kill the cells and inhibit tumor growth.”

In order to test these combinations, the researchers developed an ‘explant,’ a mini-tumor derived from a patient’s biopsy that can be grown in an environment that closely mimics its natural surroundings. The ultimate goal, says Goldman, is to map the precise order and timing of this treatment regimen in order to move toward clinical trials:

“Our goal is to build a regimen that will be [effective] for clinical trials. Once we’ve understood specific timing, sequence of drug delivery and dosage better, it will be easier to translate these findings clinically.”

All Things Being (Un)Equal: Scientists Discover Gene that Breaks Traditional Laws of Inheritance

One of the most fundamental laws of biology is about to be turned on its head, according to new research from scientists at the University of North Carolina (UNC) School of Medicine.

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As reported in the journal PLOS Genetics, UNC researchers identified a gene that does not obey traditional laws that determine how genes get passed down from parents to offspring. In experiments on laboratory mice, they found a gene called R2d2 causes female mice to pass on more genetic information than the males did—an observation that appears to contradict principles of genetic inheritance set forth more than a century ago.

As you may (or may not) remember from freshmen biology class, the laws of inheritance were laid down by the 19th century monk Gregor Mendel. Through meticulous observations of his garden’s pea plants, he found that each parent contributes their genetic information equally to their offspring.

But 150 years of scientific discovery later, scientists have discovered that this isn’t always the case.

Instead, in some cases one of the parents will contribute a greater percentage of genetic information than the other, a process called meiotic drive. Scientists had seen evidence of this process occurring in mammals for quite some time, but hadn’t narrowed down the driver of the process to a particular gene. According to UNC researchers, R2d2 is that gene. Senior author Fernando Pardo-Manuel de Villena explains:

“R2d2 is a good example of a poorly understood phenomenon known as female meiotic drive—when an egg is produced and a ‘selfish gene’ is segregated to the egg more than half the time.”

Pardo-Manuel de Villena notes that one example of this process occurs during trisomies—when three chromosomes (two from one parent and one from the other) are passed down to the embryo. The most common trisomy, trisomy 21, is more commonly known as Down Syndrome.

With these findings, Pardo-Manuel de Villena and the team are hoping to gain important insights into the underlying cause of trisomies, as well as the underlying causes for miscarriage—which are often not known.

“Understanding how meiotic drive works may shed light on the … abnormalities underlying these disorders,” said Pardo-Manuel de Villena.

This research was performed in large part by first author John Didion, who first discovered R2d2 when breeding two different types of mice for genetic analysis. Using whole-genome sequencing of thousands of laboratory mice, Didion and his colleagues saw that genes were passed down equally from each mouse’s parents. But a small section, smack dab in the middle of chromosome 2, was different.

Further analysis revealed that this section of chromosome 2 had a disproportionately larger number of genes from the mouse’s mother, compared to its father—showing a clear example of female meiotic drive. And at the heart of it all, Didion discovered, was the R2d2 gene.

The UNC team are already busy diving deeper into the relationship between R2d2 and meiotic drive with a focus on understanding, and one day perhaps correcting, genetic abnormalities in the developing embryo.

Stem cell stories that caught our eye: repairing radiation damage, beta thalassemia clinical trial and disease models

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Stem cells repair brain damage from radiation therapy. Radiation for brain cancer can be a lifesaver but it can also be a dramatic life changer. If often leaves patients with considerably reduced brain function. Now a team at New York’s Memorial Sloan Kettering Cancer Center has found a way to instruct human stem cells to repair some of that damage—at least in rats.

The damage seems to be to the middle-man or so-called progenitor cells that maintain the myelin cells that insulate the nerves in the brain. When that myelin is damaged by the radiation those progenitor cells are no longer able to make repairs and that results in reduced nerve function. Rats given the stem cells regained both cognitive and motor skills lost after brain radiation.

The team leader, Viviane Taber, noted this work could make radiation therapy even more of a lifesaver. ScienceDaily quoted Tabar from materials provided by Cell Press that published the work:

“This will have to be proven further, but if we can repair the brain effectively, we could be bolder with our radiation dosing, within limits.”

This could be especially important in children, for whom physicians deliberately deliver lower radiation doses.


Stem cell trial for Beta-Thalassemia cleared to begin.
CIRM-grantee Sangamo BioSciences announced this week that the Food and Drug Administration (FDA) had accepted its application to begin a clinical trial using genetically edited stem cells to treat patients with beta-thalassemia. This trial, in patients who require regular blood transfusions to survive, is the ninth CIRM-funded clinical trail to gain clearance from the FDA.

Other clinical trials have used genetically modified stem cells, but they have used various techniques to add a correct gene or silence an unwanted gene. This will be the first clinical trial using one of the newer techniques that actually goes into a person’s genes and edits them to correct a disease. We wrote about this beta-thalassemia project here.

The Sacramento Business Times picked up the company’s press release that quoted Sangamo president Edward Lanphier on the company’s goal, “the aim of providing transfusion-dependent beta-thalassemia patients with a one-time treatment for this devastating disease.”

Disease modeling for science wonks. Vivien Marx wrote a feature article for Nature Methods that provides the most thorough review of the use of reprogramed iPS-type stem cells as disease models that I have read. In particular she discusses the power of using new gene editing tools to modify the cells so that when they mature into adult tissues they will display specific disease traits.

Svendsen hopes to use gene-edited iPS type stem cells to fully understand neurodegenerative diseases

Svendsen hopes to use gene-edited iPS type stem cells to fully understand neurodegenerative diseases

She starts with a narrative about CIRM-grantee Clive Svendsen’s work to understand spinal muscular atropohy (SMA) when he was in Wisconsin and to understand amyotrophic lateral sclerosis (ALS) now at Cedars Sinai in Los Angeles. She goes on to show just how powerful these gene-edited stem cells can be, but also how difficult it is to use the technology in a way that generates useful information. Marx is a strong science journalist, who for many years has shown a skill at explaining complex technologies.

She also discusses the various iPS cell banks developed around the world including CIRM’s cell bank and the value of having non-gene-edited cells from patients that naturally show the disease traits.

Thorough review of changes at CIRM.
Alex Lash at xconomy wrote an in-depth overview of our president Randy Mills’ plans for the next phase of our agency that Randy calls CIRM 2.0. Calling the plans an extensive “renovation” Lash described the portions of the new structure that were already in place and listed the ones set to come online in the next six months.

As a balanced journalist he runs through some of the highs and lows of our public perception during the initial phase of the agency and then discusses the new tone set by Mills:

“CIRM is less a grant-making government agency than a ‘discerning investor’ that’s going to be ‘as creative and innovative’ as possible in getting treatments approved, Mills says. ‘We have no mission above accelerating stem cell therapies to patients.’ ”