Sonic Hedgehog provides pathway to fight blood cancers

Dr. Catriona Jamieson: Photo courtesy Moores Cancer Center, UCSD

Dr. Catriona Jamieson:
Photo courtesy Moores Cancer Center, UCSD

For a lot of people Sonic Hedgehog is a video game. But for stem cell researcher Dr. Catriona Jamieson it is a signaling pathway in the body that offers a way to tackle and defeat some deadly blood cancers.

Dr. Jamieson – a researcher at the University of California, San Diego (UCSD) – has a paper published online today in The Lancet Haematology that highlights the safety and dosing levels for a new drug to treat a variety of blood cancers. CIRM funding helped Dr. Jamieson develop this work.

The drug targets cancer stem cells, the kind of cell that is believed to be able to lie dormant and evade anti-cancer therapies before springing back into action, causing a recurrence of the cancer. The drug coaxes the cancer stem cells out of their hiding space in the bone marrow and gets them to move into the blood stream where they can be destroyed by chemotherapy.

In a news release Dr. Jamieson says the drug – known by the catchy name of PF-04449913 – uses the sonic Hedgehog signaling pathway, an important regulator of the way we develop, to attack the cancer:

“This drug gets that unwanted house guest to leave and never come back. It’s a significant step forward in treating people with refractory or resistant myeloid leukemia, myelodysplastic syndrome and myelofibrosis. It’s a bonus that the drug can be administered as easily as an aspirin, in a single, daily oral tablet.”

The goal of this first-in-human study was to test the drug for safety; so 47 adults with blood and marrow cancer were given daily doses of the drug for up to 28 days. Those who were able to tolerate the dosage, without experiencing any serious side effects, were then given a higher dose for the next 28 days. Those who experienced problems were taken off the therapy.

Of the 47 people who started the trial in 2010, 28 experienced side effects. However, only three of those were severe. The drug showed signs of clinical activity – meaning it seemed to have an impact on the disease – in 23 people, almost half of those enrolled in the study.

Because of that initial promise it is now being tested in five different Phase 2 clinical trials. Dr. Jamieson says three of those trials are at UCSD:

“Our hope is that this drug will enable more effective treatment to begin earlier and that with earlier intervention, we can alter the course of disease and remove the need for, or improve the chances of success with, bone marrow transplantation. It’s all about reducing the burden of disease by intervening early.”

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Goodnight, Stem Cells: How Well Rested Cells Keep Us Healthy

Plenty of studies show that a lack of sleep is nothing but bad news and can contribute to a whole host of health problems like heart disease, poor memory, high blood pressure and obesity.

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Even stem cells need rest to stay healthy

In a sense, the same holds true for the stem cells in our body. In response to injury, adult stem cells go to work by dividing and specializing into the cells needed to heal specific tissues and organs. But they also need to rest for long-lasting health. Each cell division carries a risk of introducing DNA mutations—and with it, a risk for cancer. Too much cell division can also deplete the stem cell supply, crippling the healing process. So it’s just as important for the stem cells to assume an inactive, or quiescent, state to maintain their ability to mend the body. Blood stem cells for instance are mostly quiescent and only divide about every two months to renew their reserves.

Even though the importance of this balance is well documented, exactly how it’s achieved is not well understood; that is, until now. Earlier this week, a CIRM-funded research team from The Scripps Research Institute (TSRI) reported on the identification of an enzyme that’s key in controlling the work-rest balance in blood stem cells, also called hematopoietic stem cells (HSCs). Their study, published in the journal Blood, could point the way to drugs that treat anemias, blood cancers, and other blood disorders.

Previous studies in other cell types suggested that this key enzyme, called ItpkB, might play a role in promoting a rested state in HSCs. Senior author Karsten Sauer explained their reasoning for focusing on the enzyme in a press release:

“What made ItpkB an attractive protein to study is that it can dampen activating signaling in other cells. We hypothesized that ItpkB might do the same in HSCs to keep them at rest. Moreover, ItpkB is an enzyme whose function can be controlled by small molecules. This might facilitate drug development if our hypothesis were true.”

Senior author Karsten Sauer is an associate professor at The Scripps Research Institute.

Senior author Karsten Sauer is an associate professor at The Scripps Research Institute.

To test their hypothesis, the team studied HSCs in mice that completely lacked ItpkB. Sure enough, without ItpkB the HSCs got stuck in the “on” position and continually multiplied until the supply of HSCs stores in the bone marrow were exhausted. Without these stem cells, the mice could no longer produce red blood cells, which deliver oxygen to the body or white blood cells, which fight off infection. As a result the animals died due to severe anemia and bone marrow failure. Sauer used a great analogy to describe the result:

“It’s like a car—you need to hit the gas pedal to get some activity, but if you hit it too hard, you can crash into a wall. ItpkB is that spring that prevents you from pushing the pedal all the way through.”

With this new understanding of how balancing stem cell activation and deactivation works, Sauer and his team have their sights set on human therapies:

“If we can show that ItpkB also keeps human HSCs healthy, this could open avenues to target ItpkB to improve HSC function in bone marrow failure syndromes and immunodeficiencies or to increase the success rates of HSC transplantation therapies for leukemias and lymphomas.”

Getting the right tools for the right job

Imagine a device that sits outside the body and works like a form of dialysis for a damaged liver, filtering out the toxins and giving the liver a chance to regenerate, and the patient a chance to avoid the need for a transplant.

Or imagine a method of enhancing the number of stem cells we can harvest or generate from umbilical cord blood, enabling us to use those stem cells and offer life-saving bone marrow transplants to all the patients who don’t have a matched donor.

Well, you may not have to imagine for too long. Yesterday, our governing Board approved almost $30 million in funding for our Tools and Technology Awards and two of the successful applications are for researchers hoping to turn those two ideas into reality.

The Tools n Tech awards may not have the glamor or cache of the big money awards that are developing treatments heading towards clinical trials, but they are nonetheless an essential part of what we do.

As our Board Chair Jonathan Thomas said in a news release they focus on developing new approaches or creating new ways of overcoming some of the biggest obstacles in stem cell research.

“Sometimes even the most promising therapy can be derailed by a tiny problem. These awards are designed to help find ways to overcome those problems, to bridge the gaps in our knowledge and ensure that the best research is able to keep progressing and move out of the lab and into clinical trials in patients.”

Altogether 20 awards were funded for a wide variety of different ideas and projects. Some focus on improving our ability to manufacture the kinds of cells we need for transplanting into patients. Another one plans to use a new class of genetic engineering tools to re-engineer the kind of stem cells found in bone marrow, making them resistant to HIV/AIDS. They also hope this method could ultimately be used to directly target the stem cells while they are inside the body, rather than taking the cells out and performing the same procedure in a lab and later transplanting them back.

Dr. Kent Leach, UC Davis School of Engineering

Dr. Kent Leach, UC Davis School of Engineering

One of the winners was Dr. Kent Leach from the University of California, Davis School of Engineering. He’s looking to make a new kind of imaging probe, one that uses light and sound to measure the strength and durability of bone and cartilage created by stem cells. This could eliminate the need for biopsies to make the same measurements, which is good news for patients and might also help reduce healthcare costs.

We featured Dr. Leach in one of our Spotlight videos where he talks about using stem cells to help repair broken bones that no longer respond to traditional methods.

Scientists Send Rodents to Space; Test New Therapy to Prevent Bone Loss

In just a few months, 40 very special rodents will embark upon the journey of a lifetime.

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Today UCLA scientists are announcing the start of a project that will test a new therapy that has the potential to slow, halt or even reverse bone loss due to disease or injury.

With grant funding from the Center for the Advancement of Science in Space (CASIS), a team of stem cell scientists led by UCLA professor of orthopedic surgery Chia Soo will send 40 rodents to the International Space Station (ISS). Living under microgravity conditions for two months, these rodents will begin to undergo bone loss—thus closely mimicking the conditions of bone loss, known as osteoporosis, seen in humans back on Earth.

At that point, the rodents will be injected with a molecule called NELL-1. Discovered by Soo’s UCLA colleague Kang Ting, this molecule has been shown in early tests to spur bone growth. In this new set of experiments on the ISS, the researchers hope to test the ability of NELL-1 to spur bone growth in the rodents.

The team is optimistic that NELL-1 could really be key to transforming how doctors treat bone loss. Said Ting in a news release:

“NELL-1 holds tremendous hope, not only for preventing bone loss but one day even restoring healthy bone. For patients who are bed-bound and suffering from bone loss, it could be life-changing.”

“Besides testing the limits of NELL-1’s robust bone-producing efforts, this mission will provide new insights about bone biology and could uncover important clues for curing diseases such as osteoporosis,” added Ben Wu, a UCLA bioengineer responsible for initially modifying NELL-1 to make it useful for treating bone loss.

The UCLA team will oversee ground operations while the experiments will be performed by NASA scientists on the ISS and coordinated by CASIS.

These experiments are important not only for developing new therapies to treat gradual bone loss, such as osteoporosis, which normally affects the elderly, but also those who have bone loss due to trauma or injury—including bone loss due to extended microgravity conditions, a persistent problem for astronauts living on the ISS. Said Soo:

“This research has enormous translational application for astronauts in space flight and for patients on Earth who have osteoporosis or other bone-loss problems from disease, illness or trauma.”

UC Davis Surgeons Begin Clinical Trial that Tests New Way to Deliver Stem Cells; Heal Bone Fractures

Each year, approximately 8.9 million people worldwide will suffer a bone fracture. Many of these fractures heal with the help of traditional methods, but for some, the road to recovery is far more difficult.

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After exhausting traditional treatments—such as surgically implanted pins or plates, bed rest and injections to spur bone growth—these patients can undergo a special type of stem cell transplant that directs stem cells extracted from the bone marrow to the fracture site to speed healing.

This procedure has its drawbacks, however. For example, the act of extracting cells from one’s own bone marrow and then injecting them into the fracture site requires two very painful surgical procedures: one to extract the cells, and another to implant them. Recovery times for each procedure, especially in older patients, can be significant.

Enter a team of surgeons at UC Davis. Who last week announced a ‘proof-of-concept’ clinical trial to test a device that can extract and isolate stem cells far more efficiently than before—and allow surgeons to implant the cells into the fracture in just a single surgery.

As described in HealthCanal, he procedure makes use of a reamer-irrigator-aspirator system, or RIA, that normally processes wastewater during bone drilling surgery. As its name implies, this wastewater was thought to be useless. But recent research has revealed that it is chock-full of stem cells.

The problem was that the stem cells were so diluted within the wastewater that they couldn’t be used. Luckily, a device recently developed by Sacramento-based SynGen, Inc., was able to quickly and efficiently extract the cells in high-enough concentrations to then be implanted into the patient. Instead of having to undergo two procedures—the patient now only has to undergo one.

“The device’s small size and rapid capabilities allow autologous stem cell transplantation to take place during a single operation in the operation room rather than requiring two procedures separated over a period of weeks,” said UC Davis surgeon Mark Lee, who is leading the clinical trial. “This is a dramatic difference that promises to make a real impact on healing and patient recovery.”

Hear more from Lee about how stem cells can be used to heal bone fractures in our 2012 Spotlight on Disease.

Stem cells and professional sports: a call for more science and less speculation

In the world of professional sports, teams invest tens of millions of dollars in players. Those players are under intense pressure to show a return on that investment for the team, and that means playing as hard as possible for as long as possible. So it’s no surprise that players facing serious injuries will often turn to any treatment that might get them back in the game.

image courtesy Scientific American

image courtesy Scientific American

A new study published last week in 2014 World Stem Cell Report (we blogged about it here) highlighted how far some players will go to keep playing, saying at least 12 NFL players have undergone unproven stem cell treatments in the last five years. A session at the recent World Stem Cell Summit in San Antonio, Texas showed that football is not unique, that this is a trend in all professional sports.

Dr. Shane Shapiro, an orthopedic surgeon at the Mayo Clinic, says it was an article in the New York Times in 2009 about two of the NFL players named in the World Stem Cell Report that led him to becoming interested in stem cells. The article focused on two members of the Pittsburgh Steelers team who were able to overcome injuries and play in the Super Bowl after undergoing stem cell treatment, although there was no direct evidence the stem cells caused the improvement.

“The next day, the day after the article appeared, I had multiple patients in my office with copies of the New York Times asking if I could perform the same procedure on them.”

Dr. Shapiro had experienced what has since become one of the driving factors behind many people seeking stem cell therapies, even ones that are unproven; the media reports high profile athletes getting a treatment that seems to work leading many non-athletes to want the same.

“This is not just about high profile athletes it’s also about older patients, weekend warriors and all those with degenerative joint disease, which affects around 50 million Americans. Currently for a lot of these degenerative conditions we don’t have many good non- surgical options, basically physical therapy, gentle pain relievers or steroid injections. That’s it. We have to get somewhere where we have options to slow down this trend, to slow down the progression of these injuries and problems.”

Shapiro says one of the most popular stem cell-based approaches in sports medicine today is the use of plasma rich platelets or PRP. The idea behind it makes sense, at least in theory. Blood contains platelets that contain growth factors that have been shown to help tissue heal. So injecting a patient’s platelets into the injury site might speed recovery and, because it’s the patient’s own platelets, the treatment probably won’t cause any immune response or prove to be harmful.

That’s the theory. The problem is few well-designed clinical trials have been done to see if that’s actually the case. Shapiro talked about one relatively small, non-randomized study that used PRP and in a 14-month follow-up found that 83% of patients reported feeling satisfied with their pain relief. However, 84% of this group did not have any visible improved appearance on ultrasound.

He is now in the process of carrying out a clinical trial, approved by the Food and Drug Administration (FDA), using bone marrow aspirate concentrate (BMAC) cells harvested from the patient’s own bone marrow. Because those cells secrete growth factors such as cytokines and chemokines they hope they may have anti-inflammatory and regenerative properties. The cells will be injected into 25 patients, all of whom have arthritic knees. They hope to have results next year.

Dr. Paul Saenz is a sports medicine specialist and the team physician for the San Antonio Spurs, the current National Basketball Association champions. He says that sports teams are frequently criticized for allowing players to undergo unproven stem cell treatments but he says it’s unrealistic to expect teams to do clinical studies to see if these therapies work, that’s not their area of expertise. But he also says team physicians are very careful in what they are willing to try.

“As fervent as we are to help bring an athlete back to form, we are equally fervent in our desire not to harm a $10 million athlete. Sports physicians are very conservative and for them stem cells are never the first thing they try, they are options when other approaches have failed.”

Saenz said while there are not enough double blind, randomized controlled clinical trials he has seen many individual cases, anecdotal evidence, where the use of stem cells has made a big difference. He talked about one basketball player, a 13-year NBA veteran, who was experiencing pain and mobility problems with his knee. He put the player on a biologic regimen and performed a PRP procedure on the knee.

“What we saw over the next few years was decreased pain, and a dramatic decrease in his reliance on non-steroidal anti inflammatory drugs. We saw improved MRI findings, improved athletic performance with more time on court, more baskets and more rebounds.”

But Saenz acknowledges that for the field to advance anecdotal stories like this are not enough, well-designed clinical trials are needed. He says right now there is too much guesswork in treatments, that there is not even any agreement on best practices or standardized treatment protocols.

Dr. Shapiro says for too long the use of stem cells in sports medicine has been the realm of individual physicians or medical groups. That has to change:

“If we are ever to move forward on this it has to be opened up to the scientific community, we have to do the work, do the studies, complete the analysis, open it up to our peers, report it in a reputable journal. If we want to treat the 50 million Americans who need this kind of therapy we need to go through the FDA approval process. We can’t just continue to treat the one patient a month who can afford to pay for all this themselves. “

No Fear of Rejection? Partial Stem Cell Transplant Reverses Sickle Cell Disease—even without Immunosuppressant Drugs

For those who suffer from the blood disorder sickle cell disease, there is really only one cure: a full bone marrow transplant followed by a lifetime of anti-rejection, immune-suppressing drugs. But now, researchers from the National Institutes of Health are testing an attractive alternative for the sickest patients.

Sickle cell disease gets its name from a single genetic change, or mutation, that alters the shape of one’s red blood cells.. Unlike the round cells that can pass easily through the body’s blood vessels, the sickle-shaped cells clump together, clogging up blood vessels. This leads to a lifetime of severe joint pain and, in many cases, organ damage and stroke. In this country it affects primarily African Americans.

Magnified blood sample of a patient with severe sickle cell disease.

Magnified blood sample of a patient with severe sickle cell disease.

The only cure is a bone marrow transplant, in which the patient’s own bone marrow is first depleted with chemotherapy, and replaced by the donor marrow. The patient then faces a lifetime of immunosuppressant, anti-rejection medication to prevent deadly rejection or graft-versus-host disease, a potentially fatal condition where the donor cells attack the recipient’s immune system.

But what if, instead of replacing the entirety of the patient’s bone marrow, doctors only replaced some of it? Would this mix of sickle and non-sickle-shaped cells be enough to reverse the symptoms? A clinical trial published today from the NIH research team in the Journal of the American Medical Association has some encouraging results.

As lead author Dr. Matthew Hsieh noted in today’s press release:

“Typically, stem-cell recipients must take immunosuppressants all their lives. That the patients who discontinued this medication were able to do so safely points to the stability of the partial transplant regimen.”

In this study, the researchers performed partial bone marrow transplantations on 30 adults with severe sickle cell disease. After one year, they took 15 patients off the standard regimen of immunosuppressant drugs. And more than three years later, those 15 patients remain free from rejection.

These results are promising, in that a lifetime of immunosuppressants comes with its own set of negative side effects for the patient. According to the paper’s senior author Dr. John Tinsdale:

“Side effects caused by immunosuppressants can endanger patients already weakened by years of organ damage from sickle cell disease. Not having to permanently rely on this medication…means that even older patients and those with severe sickle cell disease may be able to reverse their condition.”

Indeed, the research team found that even a partial transplant—which resulted in a stable mix of both red blood cell types from donor and recipient – was sufficient to reverse the disease’s debilitating symptoms.

The results from this trial open the door to treating patients whose immune systems are already too weak—and are unable to tolerate the negative effects of a full stem cell transplant.

But even this half transplant has the risks associated with donor marrow. That is why CIRM is funding a team using a patient’s own stem cells and genetically modifying them to produce the correct version of the mutated protein. These self-transplants would be safer and open up the therapy to all patients regardless of their ability to find an immunologically matching donor. We expect a clinical trial with this approach to begin soon.

Want to know more about how CIRM-funded scientists are working toward this goal? Check out our “Spotlight on Sickle Cell Disease.”

Stem cell stories that caught our eye: fingering chemical cancer cause, treating leukemia and getting better ID on cells

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 model environmental damage. Using human embryonic stem cells to generate prostate tissue in mice, a team at the University of Illinois has shown how the endocrine-disrupting chemical BPA can lead to prostate cancer. They implanted the cells, derived from human stem cells, along with supportive rodent cells in mice and then fed the mice a diet with low levels of BPA. As the cells matured into prostate tissue in the animals the chemical seemed to reprogram the cells in a manner that raises the risk for cancer. The team reported its work at the annual meeting of the Endocrine Society in Chicago this week and the association’s press release was picked up by Bio-Medicine.

Protecting stem cell “home” may be new therapy. A Spanish team has discovered that certain rare leukemias, known as myeloproliferative disorders, seem to be triggered by damage to the area where stem cells hang out in our bone marrow known as the stem cell niche. Normally the niche controls the behavior of blood-forming stem cells but when it gets inflamed that control breaks down the team reported in the journal Nature. But there is good news, they tested a currently available drug in an animal model and it seemed to reverse the damage to the niche and return normal stem cell controls. ScienceDaily ran a story about the work.

Clever trick could make stem cell frequent fliers. Researchers often share stem cells with colleagues around the world by freezing them first. But in some uses, it would be better if the cells could be shipped in living cultures. That usually requires some sort of electrical motor to agitate the vials to keep the cells from clumping, but airlines don’t allow running electric motors in cargo on planes. So a group of engineering students at the University of California, San Diego, has taken cues from old pendulum clocks and developed a spring powered motor that can keep the cells agitated. As our field gets ready to commercialize cell products, there may be times this could help centralize mass production of cells for shipping. Medical Design Technology explained the students’ project.

Getting a better ID on the “other” bone marrow stem cell. Most people know that our bone marrow has blood-forming stem cells, but it also has mesenchymal stem cells (MSCs). Those cells can form bone, cartilage and fat and release proteins that seem to direct the work of other stem cells. Those skills have led to more than 200 clinical trials investigating the potential of MSCs to treat many diseases. But those trials have often produced results that are hard to interpret, and many researchers in the field say part of the problem comes from our inability to accurately identify true MSCs resulting in most clinical trials using a mixed population of cells. Now one of the leaders in the field, Sean Morrison at the University of Texas Southwest Medical Center, reports that his team has found a reliable marker for MSCs known as leptin receptor. His current work was in mice, but if it can be duplicated with human cells, it could increase the chances for valuable data coming from MSC trials.

Don Gibbons