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.”

How the human genome is unlocking some of the secrets of stem cells, hopefully leading to new treatments

A little over a year ago we set aside $40 million to study how variations in the human genome – the complete map of our genetic information – can affect our ability to use stem cells to treat a wide variety of diseases and disorders.

Human-Genome-Project_finalThat money helped set up the Stanford/Salk Center of Excellence in Stem Cell Genomics (CESCG) with a goal of using genomic analysis to better understand how stem cells change as they grow and become different kinds of cells, and then use that knowledge to develop new treatments for a wide variety of conditions.

Now the CESCG has just announced it is investing $11.6 million on seven different projects aimed at gaining a deeper understanding of deadly or disabling diseases and conditions, such as heart disease and autism.

As Stanford’s Dr. Michael Snyder, a co-Principal Investigator on the project, said in a news release, a major part of CESCG’s mission is to “establish a Collaborative Research Program (CRP) to support the genomics research needs of stem cell investigators in California,”

‘We don’t just provide funds we also partner with the individual researchers, providing them with the support, expertise and resources they need to conduct successful genomics analyses. We received 30 applications from throughout the State, and after peer review 7 projects were identified as the best new collaborations for the Center.”

So how does this advance stem cell science? Well, in the past researchers often depended on animal models for their work; but because results in animals don’t always translate when applied to people this was not always an effective way to work. At the University of California, San Francisco and the University of California, Los Angeles researchers Arnold Kriegstein and Gay Crooks are using genomics to better understand normal human cell identities in the brain (UCSF) and the blood (UCLA) and then applying that knowledge to help develop more accurate and more detailed stem cell-based models for us to study.

Jonathan Thomas, the Chair of our Board, says one of the best ways to do great science, is to create a great team:

“The goal of the Board in creating this program and bringing together this group of researchers was to accelerate our fundamental understanding of human biology and the ways that disease work. That knowledge will help point the way not just to new treatments but also, hopefully, to ways that those treatments can potentially be tailored to meet the needs of individual patients.”

Heroic three-year study reveals safe methods for growing clinical-grade stem cells

Imagine seeking out the ideal pancake recipe: should you include sugar or no sugar? How about bleached vs. unbleached flour? Baking power or baking soda? When to flip the pancake on the skillet? You really have to test out many parameters to get that perfectly delicious light and fluffy pancake.

Essentially that’s what a CIRM-funded research team from both The Scripps Research Institute (TSRI) and UC San Diego accomplished but instead of making pancakes they were growing stem cells in the lab. In a heroic effect, they spent nearly three years systematically testing out different recipes and found conditions that should be safest for stem cell-based therapies in people. Their findings were reported today in PLOS ONE.

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Pluripotent stem cells. Courtesy of Andres Bratt-Leal from Jeanne Loring’s laboratory.

Let’s step back a bit in this story. If you’re a frequent reader of The Stem Cellar you know that one of the reasons stem cells are such an exciting field of biology is their pluripotency. That is, these nondescript cells have the capacity to become any type of cell in the body (pluri= many; potency = potential). This is true for embryonic stem cells and induced pluripotent cells (iPS). Several clinical trials underway or in development aim to harness this shape-shifting property to return insulin producing cells to people living with diabetes or to restore damaged nerves in victims of spinal cord injury, to name just two examples.

The other defining feature of pluripotent stem cell is their ability to make copies of themselves and grow indefinitely on petri dishes in the laboratory. As they multiply, the cells eventually take up all the real estate on the petri dish. If left alone the cells exhaust their liquid nutrients and die. So the cells must regularly be “passaged”; that is, removed from the dish and split into more dishes to provide new space to grow. This is also necessary for growing up enough quantities of cells for transplantation in people.

Previous small scale studies have observed that particular recipes for growing pluripotent cells can lead to genetic instability, such as deletion or duplication of DNA, that is linked with cancerous growth and tumor formation. This is perhaps the biggest worry about stem cell-based transplantation treatments: that they may cure disease but also cause cancer.

To find the conditions that minimize this genetic instability, the research team embarked on the first large-scale systematic study of the effects of various combinations of cell growth methods. One of the senior authors Louise Laurent, assistant professor at UC San Diego, explained in a press release the importance of this meticulous, quality control study:

“The processes used to maintain and expand stem cell cultures for cell replacement therapies needs to be improved, and the resulting cells carefully tested before use.”

To seek the ideal recipe, the team tested several parameters. For example, they grew some cells on top of so-called “feeder cells”, which help the stem cells grow while other cells used feeder-free conditions. Two different passaging methods were examined: one uses an enzyme solution to strip the cells off the petri dish while in the other method the cells are manually removed. Different liquid nutrients for the cell were included in the study as well. The different combinations of cells were grown continuously through 100 passages and changes in their genetic stability were periodically analyzed along the way.

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Jeanne Loring (above) is professor of developmental neurobiology at TSRI and senior author of the study with Louise Laurent of the University of California, San Diego.

The long-term experiment paid off: the team found that the stem cells grown on feeder free petri dishes and passaged using the enzyme solution accumulated more genetic abnormalities than cells grown on feeder cells and passaged manually. The team also observed genetic changes after many cells passages. In particular, a recurring deletion of a gene called TP53. This gene is responsible for making a protein that acts to suppress cancers. So without this suppressor, later cell passages have the danger of becoming cancerous.

Based on these results, the other senior author, Jeanne Loring, a professor of developmental neurobiology at TSRI, gave this succinct advice:

“If you want to preserve the integrity of the genome, then grow your cells under those conditions with feeder cells and manual passaging. Also, analyze your cells—it’s really easy.”

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.

Roadmap to our epigenome reveals the genetic switches that make one adult cell type different from others

A decade ago scientists made a huge news splash when they announced the completion of the human genome project declaring it the first road map of our genes. But it did not take long to realize that the early road map was like some of the early days of GPS systems: it lacked knowledge of many on-ramps, off-ramps and one-way streets.

Today, the scientific world announced a massive fix to its genetic GPS. While all of our cells carry the same genes, their function varies wildly based one which genes are turned off, which are turned on, and even which are turned on in a hyper active way. Complex chemical and structural changes in the chromosomes that house our genes—collectively called the epigenome—determine that activity.

This video from Nature explaining the epigenome with music metaphors is linked in the last paragraph.

This video from Nature explains the epigenome with music metaphors.


A massive project, mostly funded by the National Institutes of Health through a consortium of research teams around the country, published a series of papers today in Nature. The Roadmap Epigenomic Consortium did extensive analysis of 111 epigenomes from different types of cells: normal heart tissue and immune cells, for example, as well as cells from patients with diseases such as neurons from patients with Alzheimer’s. The Scientist this morning quoted one member of the Consortium, MIT’s Manolis Kellis:

“The human epigenome is this collection of . . . chemical modifications on the DNA itself and on the packaging that holds DNA together. All our cells have a copy of the same book, but they’re all reading different chapters, bookmarking different pages, and highlighting different paragraphs and words.”

CIRM funding contributed to two of the papers authored by a team at the University of California, San Diego. One of the papers looked at how the genetic structure of stem cells changes as they mature and differentiate into specific types of adult tissue. The other looked at how structural differences determine which of the chromosomes we inherit—the one from mom or the one from dad—has a stronger influence on specific traits. The senior author on the studies, Bing Ren, noted in a university press release that these differences will be important as we think about individualizing therapies:

“Both of these studies provide important considerations for clinicians and researchers who are developing personalized medicines based on a patient’s genomic information”

The consortium’s publications today resulted from a massive data analysis. A press release from the Broad Institute in Cambridge, Massachusetts, describes the effort that required grouping two million predicted areas of change in the chromosomes into 200 sets or modules and then looking for how those modules impacted different cell types.

But if you are still having trouble understanding the concept of the epigenome, I highly recommend taking the five minutes it takes to watch this video produced by Nature. It equates the process to a symphony and what occurs when you change notes and intensity in the score.

Meryl Streep, Lindsay Lohan and the importance of staying above the fray in science communications

Carl Sagan: photo courtesy Brainpickings.org

Carl Sagan: photo courtesy Brainpickings.org

Carl Sagan, the astronomer and cosmologist (among many other things) once said: “We live in a society absolutely dependent on science and technology, and yet have cleverly arranged things so that almost no one understands science and technology. That’s a clear prescription for disaster.”

The goal of two panel discussions at the American Association for the Advancement of Science (AAAS) conference in San Jose last week was to find ways to change that: to get the public to both understand and care more about science and technology; and to get scientists to do a better job of explaining both to them.

The first challenge of course is finding scientists who want to be part of this public conversation. Dr. Nalini Nadkarni, an ecologist who studies rain forests, said for young scientists in particular it’s not just a matter of having the right skills, it’s also a matter of finding the time:

“One of the challenges of scientific engagement is that just being a scientist is a full-time job, and it’s hard to think about doing public engagement when you are trying to build a career.”

Dr. Anthony Dudo, who studies the intersection of science, media and society, says one thing universities can do is encourage outreach and engagement, maybe even make it a factor in a teacher getting tenure. He says there are a lot of researchers who are happy to do this kind of outreach – either through public talks or media interviews – and they do it for all sorts of reasons.

“Many do it because it’s something they enjoy, they consider it a civic duty, something that sparks public interest in science and raises awareness about their field. In addition some say it can enhance their own scientific reputation and increase visibility for funding.”

But there is a risk. Some scientists reported facing a backlash from colleagues who felt they were trying to hog the limelight. They fell victim to what is called the “Carl Sagan” effect, which holds that if someone is spending that much time and effort communicating science to the public they must not be a very good scientist to start with.

No one could accuse Stanford’s Dr. Noah Diffenbaugh of not being a good scientist – he specializes in studying climate change and you can read his extensive resume here –  but he is also a gifted communicator, something he says he feels is his duty:

“I feel it is my responsibility to answer questions from the public when asked, because my research group is publicly funded by taxpayer dollars through agencies like the NSF. And as a public citizen I feel responsible that if we are having a public dialogue about climate change that I should be part of that dialogue.”

But he says he is very careful to avoid taking sides in the debate. He tells of an interview he once heard where Oscar-winning actress Meryl Streep talked about the importance of keeping her personal life and beliefs private (as opposed to Lindsay Lohan’s very public private life). Streep says as an actress she wants people to be able to look at her on screen and focus on the character she is playing, and not be distracted by thinking about any very public shenanigans she may have been involved in. Diffenbaugh says a scientist’s credibility depends on them doing the same:

“I stick to the facts and don’t express personal opinions or offer advocacy positions. I feel strong that in public discussions about climate change that someone in the conversation needs to be focused on evidence. It’s a role that scientists are fundamentally equipped to play.”

But even the best communicators are finding it increasingly hard to get their message into the media these days. Fewer and fewer newspapers or TV stations have skilled, experienced health and science writers, which makes it difficult to reach the public.

Lisa Krieger is an award-winning science journalist at the San Jose Mercury News. She says she finds it challenging getting stories she wants to write into the paper because she is competing for shrinking space against stories that might seem more relevant to local readers:

“Basic science is hard to cover because readers want to know how it will benefit them directly and sometimes these things are years, or even decades, away from having any real impact on people. And that’s a hard sell to an editor to get those kinds of stories into the paper.”

Krieger says the key to getting the message out is making it personal, tell stories about real people, about the real impact something could have on someone.

While acknowledging the challenges, and risks, of being a public voice and face for science – particularly when there is so much political polarization around science these days – everyone agreed that we need more scientists who are willing and able to talk about their work in ways that will engage the public, help them understand what is being done and why they should care.

For Carl Sagan (yes, him again) the reason why scientists should engage with the public was simple; to share knowledge about the wonders of the world we live in.

“It is sometimes said that scientists are unromantic, that their passion to figure out robs the world of beauty and mystery. But is it not stirring to understand how the world actually works—that white light is made of colors, that color is the way we perceive the wavelengths of light, that transparent air reflects light, that in so doing it discriminates among the waves, and that the sky is blue for the same reason that the sunset is red? It does no harm to the romance of the sunset to know a little bit about it.”

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.”