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.”

Two studies show genes and their switches critical to brain cancer’s resistance to therapy

Two California teams discovered genetic machinery that cancer stem cells in high-grade brain cancers use to evade therapy. One CIRM-funded team at Cedars-Sinai in Los Angeles pinpointed a family of genes that turn off other genes that chemotherapy targets —effectively hiding them from the chemo. The other team at the University of California, San Diego (UCSD), found a culprit switch among the molecules that surround genes in the DNA.

Chemical switches like those found at UCSD control much of how our cells function. These so called epigenetic markers can toggle between on and off states and result in two cells with the same genes behaving differently. That is what the San Diego team found when they transplanted cells from the same glioblastoma brain cancer into different mice. Some readily formed new tumors and some did not.

“One of the most striking findings in our study is that there are dynamic and reversible transitions between tumorigenic and non-tumorigenic states in glioblastoma that are determined by epigenetic regulation,” said senior author Clark Chen. “This plasticity represents a mechanism by which glioblastoma develops resistance to therapy.”

The switch the cancer stem cells used in this case is called LSD1 and the researchers hope to be able to learn how to manipulate that switch to make the brain cancer stem cells more vulnerable to therapy.

Brain caner cells (left) that don’t readily form new tumors can spontaneously acquire cancer stem cell characteristics (right).

Brain caner cells (left) that don’t readily form new tumors can spontaneously acquire cancer stem cell characteristics (right).

The family of genes fingered by the Cedars team control the on-off status of a number of genes associated with cancer stem cells. That family, called Ets factors, is quite large but the brain tumor model used by the team allows them to quickly determine which genes are being impacted by the Ets factors.

“The ability to rapidly model unique combinations of driver mutations from a patient’s tumor enhances our quest to create patient-specific animal models of human brain tumors,” said Moise Danielpour the senior author on the study

The team’s next step: testing the function of the various Ets factors to see what their specific roles are in tumor progression.

Given the dismal five-year survival rate for high-grade brain cancers these advances in understanding their genetic machinery should push the field toward better therapy.

The Cedars team published in the journal Cell Reports and Health Canal picked up the hospital’s press release. The UCSD team published in the Proceedings of the National Academy of Sciences and Science Daily picked up the university’s press release. CIRM funds a number of projects working on new therapies for brain cancer.

Partnering with Big Pharma to benefit patients

Our mission at CIRM is to accelerate the development of stem cell therapies for patients with unmet medical needs. One way we have been doing that is funding promising research to help it get through what’s called the “Valley of Death.” This is the time between a product or project showing promise and the time it shows that it actually works.

Many times the big pharmaceutical companies or deep pocketed investors, whose support is needed to cover the cost of clinical trials, don’t want to get involved until they see solid proof that this approach works. However, without that support the researchers can’t do the early stage clinical trials to get that proof.

The stem cell agency has been helping get these projects through this Catch 22 of medical research, giving them the support they need to get through the Valley of Death and emerge on the other side where Big Pharma is waiting, ready to take them from there.

We saw more evidence that Big Pharma is increasingly happy doing that this week with the news that the University of California, San Diego, is teaming up with GSK to develop a new approach to treating blood cancers.

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

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

Dr. Catriona Jamieson is leading the UCSD team through her research that aims at killing the cancer stem cells that help tumors survive chemotherapy and other therapies, and then spread throughout the body again. This is work that we have helped fund.

In a story in The San Diego Union Tribune, reporter Brad Fikes says this is a big step forward:

“London-based GSK’s involvement marks a maturation of this aspect of Jamieson’s research from basic science to the early stages of discovering a drug candidate. Accelerating such research is a core purpose of CIRM, founded in 2004 to advance stem cell technology into disease therapies and diagnostics.”

The stem cell agency’s President and CEO, Dr. C. Randal Mills, is also quoted in the piece saying:

“This is great news for Dr. Jamieson and UCSD, but most importantly it is great news for patients. Academic-industry partnerships such as this bring to bear the considerable resources necessary to meaningfully confront healthcare’s biggest challenges. We have been strong supporters of Dr. Jamieson’s work for many years and I think this partnership not only reflects the progress that she has made, but just as importantly it reflects how the field as a whole has progressed.”

As the piece points out, academic researchers are very good at the science but are not always as good at turning the results of the research into a marketable product. That’s where having an industry partner helps. The companies have the experience turning promising therapies into approved treatments.

As Scott Lippman, director of the Moores Cancer Center at UCSD, said of the partnership:

“This is a wonderful example of academia-industry collaboration to accelerate drug development and clinical impact… and opens the door for cancer stem cell targeting from a completely new angle.”

With the cost of carrying out medical research and clinical trials rising it’s hard for scientists with limited funding to go it alone. That’s why these partnerships, with CIRM and industry, are so important. Working together we make it possible to speed up the development and testing of therapies, and get them to patients as quickly as possible.

Stem cell stories that caught our eye: Immune therapy for HIV, nerves grown on diamonds and how stem cells talk

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.

Trendy CAR T therapy tried on HIV.  The hottest trend in cancer therapy today is using CAR-T cells to attack and rid the body of cancer. Technically called chimeric antigen receptors the technology basically provides our own immune system with directions to cancer cells and keys to get inside them and destroy them. A CIRM-funded team at the University of California, Los Angeles, has now tried that same scheme with HIV.

Jerome Zack (left) and Scott Kitchen, found that the technique decreased HIV levels in mice by 80 to 95 percent.

Jerome Zack (left) and Scott Kitchen, found that the technique decreased HIV levels in mice by 80 to 95 percent.

The researchers worked with mice bred to have a human immune system so that HIV affects them similarly to humans. They harvested their blood-forming stem cells and inserted a CAR that recognized HIV. After giving the stem cells back to the mice they produced T cells capable of seeking out and destroying about 90 percent of the virus. The technique has a ways to go, but the study’s lead author noted their ultimate goal in a University press release picked up by HealthCanal:

“We hope this approach could one day allow HIV-positive individuals to reduce or even stop their current HIV drug regimen and clear the virus from the body altogether,” said Scott Kitchen. “We also think this approach could possibly be extended to other diseases.”

Nerves grown on diamonds. Diamonds are so chemically non-reactive our bodies would not recognize them as foreign. But they can also be made to conduct electricity, which could make nerves grown on their surface able to be turned on and off with electrical impulses. When developing cell therapy for several neurologic diseases the ability to control the activity of replacement cells could be critical to success—making new research by a team in Britain and Ireland intriguing, if very preliminary.

They doped diamonds with boron to make them able to conduct electricity and then used them as a surface for growing nerve stem cells that could later be turned into nerves. They then succeeded in growing nerves long term on the diamonds.

“We still have a lot more fundamental studies of the neuron/diamond interface to perform,” said Paul May of the University of Bristol. “[But] the long term possibilities for this work are exciting.  Long-lifetime diamond bio-implants may offer treatments for Parkinson’s, Alzheimer’s, stroke or even epilepsy.”

Materials Today wrote a piece explaining the work.

Some stem cells talk over “land lines.” Most cellular communication works through chemical signals that get dispatched by one cell and received by others. It turns out that some types of stem cells communicate by sending out tiny nanotubes, sort of a cellular land line.

A team at the University of Michigan and the University of Texas Southwestern Medical Center found the new form of communication working with fruit flies. Yukiko Yamashita, a senior author of the paper from Michigan explained why it is so important to get a better understanding of cell-to-cell communication in a university press release picked up by ScienceNewsline:

“There are trillions of cells in the human body, but nowhere near that number of signaling pathways. There’s a lot we don’t know about how the right cells get just the right messages to the right recipients at the right time.”

In a classic example of the beauty of young minds in science, prior images of these stem cells had shown the nanotubes, but they had been overlooked until a graduate student asked what they were.

Phase 3 melanoma trial explained. When a new therapy gets into its third and final phase of testing it is make or break for the company developing the therapy and for patients who hope it will become broadly available. CIRM recently provided funding to our first phase three clinical trial, one aimed at metastatic melanoma being conducted by Caladrius Biosciences.

The CEO of the company, David Mazzo, gave an interview with The New Economy this week that does a nice job of explaining the goal of the therapy and how it is different from other therapies currently used or being developed. The therapy’s main difference is its ability to target the cancer-inducing cells thought to responsible for the spread of the disease.

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

One of the great privileges and pleasures of working at the stem cell agency is the chance to meet and work with some remarkable people, such as my colleagues here at CIRM and the researchers we support. But for me the most humbling, and by far the most rewarding experience, is having a chance to get to know the people we work for, the patients and patient advocates.

Norm Beegun, got stem cell therapy for metastatic melanoma

Norm Beegun, got stem cell therapy for metastatic melanoma

At our May Board meeting I got to meet a gentleman who exemplifies everything that I truly admire about the patients and patient advocates. His name is Norm Beegun. And this is his story.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

When you get to meet people like Norm, how could you not love this job.

Stem cell stories that caught our eye: sickle cell patient data, vaccine link to leukemia protection, faster cell analysis

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.

Good news from sickle cell clinical trial. It is always satisfying to report positive results from human clinical trials using stem cells even when we don’t fund the work. Bluebird Bio released the first data on a patient treated for sickle cell anemia using the same procedure the company had earlier used to get good outcomes for two patients with beta thalassemia.

Both diseases result from defects—though different defects—in the gene for hemoglobin, the protein our red blood cells use to carry needed oxygen. So, in both cases they use a modified, deactivated virus to carry a correct version of the gene into patients’ own blood-forming stem cells in the lab. They then re-infused those cells into the patients to provide a ready supply of cells able to make the needed protein.

In the sickle cell patient, after the transplant a third of his red cells were making the right protein and that was enough to wean him off blood transfusions that had been keeping him alive and prevented any further hospitalizations due to the disease. The company also announced that the two previously reported patients treated for beta thalassemia had continued to improve. Reuters ran a story on the new data.

CIRM funds a similar project about to begin treating patients for sickle cell disease (link to video), also using a viral vector but a somewhat different one, so it is reassuring to see viral gene carriers working without side effects.

Another reason to vaccinate, prevent leukemia. While it has been known for some time that infant vaccination seems to have driven down the rate of childhood leukemia, no one has known why. A CIRM-funded team at the University of California, San Francisco, thinks they have figured it out. Viral infections trigger inflammation and the production of enzymes in cells that cause genetic mutations that lead to the cancer.

They worked with Haemophilus influenza Type b (Hib) vaccine but suggest a similar mechanism probably applies to other viral infections, and correspondingly, protection from other vaccines. The senior author on the paper, Marcus Muschen, explained the process in a university press release posted at Press-News.org

“These experiments help explain why the incidence of leukemia has been dramatically reduced since the advent of regular vaccinations during infancy. Hib and other childhood infections can cause recurrent and vehement immune responses, which we have found could lead to leukemia, but infants that have received vaccines are largely protected and acquire long-term immunity through very mild immune reactions.”

Barcoding individual cells. Our skin cells all pretty much look the same, but in the palm of your hand there are actually several different types of cells, even a tiny scratch of the fingernail. As scientist work to better understand how cells function, and in particular how stem cells mature, they increasingly need to know precisely what genes are turned on in individual cells.

Both techniques use tiny channels to isolate individual cells and introduce beads with "bar codes."

Both techniques use tiny channels to isolate individual cells and introduce beads with “bar codes.”

Until recently, all this type of analysis blended up a bunch of cells and asked what is in the collective soup. And this did not get the fine-tuned answers today’s scientists are seeking. Numerous teams over the past couple years have reported on tools to get down to single-cell gene analysis. Now, two teams at Harvard have independently developed ways to make this easier. They both use a type of DNA barcode on tiny beads that gets incorporated into individual cells before analysis.

Allan Klein, part of one team based at the Harvard Medical School’s main campus, described why the work is needed in a detailed narrative story released by the school:

“Does a population of cells that we initially think is uniform actually have some substructure. What is the nature of an early developing stem cell? . . . How is [a cell’s] fate determined? “

Even Macosko who worked with the other team centered at the Broad Institute of Harvard and MIT, noted the considerable increase in ease and decrease in cost with the new methods compared to some of the early methods of single cell gene analysis:

“If you’re a biologist with an interesting question in mind, this approach could shine a light on the problem without bankrupting you. It finally makes gene expression profiling on a cell-by-cell level tractable and accessible. I think it’s something biologists in a lot of fields will want to use.”

The narrative provides a good example of what we called the “bump rate” when I was at Harvard Med. Good science often moves forward when scientists bump into each other, and with Harvard Medical faculty scattered at 17 affiliated hospitals and research institutes scattered across Boston and Cambridge we were always looking for ways to increase the bump rate with conferences and cross department events. Macosko and Klein found out they were both working on similar systems at a conference.

Brain’s Own Activity Can Fuel Growth of Deadly Brain Tumors, CIRM-Funded Study Finds

Not all brain tumors are created equal—some are far more deadly than others. Among the most deadly is a type of tumor called high-grade glioma or HGG. Most distressingly, HGG’s are the leading cause of brain tumor death in both children and adults. And despite extraordinary progress in cancer research as a whole, survival rates for those diagnosed with an HGG have yet to improve.

shutterstock_30402241

But recent research from Stanford University scientists could one day help move the needle—and give renewed hope to the patients and their families affected by this devastating disease.

The study, published today in the journal Cell, found that one key driver for HGG’s deadly diagnosis is that the tumor can be stimulated to grow by the brain’s own neural activity—specifically the nerve activity in the brain’s cerebral cortex.

Michelle Monje, senior author of the study that was funded in part by two grants from CIRM, was initially surprised by these results, as they run counter to how most types of tumors grow. As she explained in today’s press release:

“We don’t think about bile production promoting liver cancer growth, or breathing promoting the growth of lung cancer. But we’ve shown that brain function is driving these brain cancers.”
 


By analyzing tumor cells extracted from HGG patients, and engrafting it onto mouse models in the lab, the researchers were able to pinpoint how the brain’s own activity was driving tumor growth.

The culprit: a protein called neuroligin-3 that appeared to be calling the shots. There are four distinct types of HGGs that affect the brain in vastly different ways—and have vastly different molecular and genetic characteristics. Interestingly, says Monje, neuroligin-3 played the same role in all of them.

What was so disturbing to the research team, says Monje, is that neuroligin-3 is an essential protein for overall brain development. Specifically, it helps maintain healthy growth and repair of brain tissue over time. In order to grow, HGG tumors hijack this critical protein.

The research team came to this conclusion after a series of experiments that delved deep into the molecular mechanisms that guide both brain activity and brain tumor development. They first employed a technique called optogenetics, whereby scientists use genetic manipulation to insert light-sensitive proteins into the brain cells, or neurons, of interest. This allowed scientists to activate these neurons—or deactivate them—at the ‘flick of a switch.’

When applying this technique to the tumor-engrafted mouse models, the team could then see that tumors grew significantly better when the neurons were switched on. The next step was to narrow it down to why. Additional biochemical analyses and testing on the mouse models confirmed that neuroligin-3 was being hijacked by the tumor to spur growth.

And when they dug deeper into the connection between neuroligin-3 and cancer, they found something even more disturbing. A detailed look at the Cancer Genome Atlas (a large public database of the genetics of human cancers), they found that HGG patients with higher levels of neuroligin-3 in their brain had shorter survival rates than those with lower levels of the same protein.

These results, while highlighting the particularly nefarious nature of this class of brain tumors, also presents enormous opportunity for researchers. Specifically, Monje hopes her team and others can find a way to block or nullify the presence of neuroligin-3 in the regions surrounding the tumor, creating a kind of barrier that can keep the size of the tumor in check. 


Stem Cell Scientists Reconstruct Disease in a Dish; Gain Insight into Deadly Form of Bone Cancer

The life of someone with Li-Fraumeni Syndrome (LFS) is not a pleasant one. A rare genetic disorder that usually runs in families, this syndrome is characterized by heightened risk of developing cancer—multiple types of cancer—at a very young age.

People with LFS, as the syndrome is often called, are especially susceptible to osteosarcoma, a form of bone cancer that most often affects children. Despite numerous research advances, survival rates for this type of cancer have not improved in over 40 years.

shutterstock_142552177 But according to new research from Mount Sinai Hospital and School of Medicine, the prognosis for these patients may not be so dire in a few years.

Reporting today in the journal Cell, researchers describe how they used a revolutionary type of stem cell technology to recreate LFS in a dish and, in so doing, have uncovered the series of molecular triggers that cause people with LFS to have such high incidence of osteosarcoma.

The scientists, led by senior author Ihor Lemischka, utilized induced pluripotent stem cells, or iPSCs, to model LFS—and osteosarcoma—at the cellular level.

Discovered in 2006 by Japanese scientist Shinya Yamanaka, iPSC technology allows scientists to reprogram adult skin cells into embryonic-like stem cells, which can then be turned into virtually any cell in the body. In the case of a genetic disorder, such as LFS, scientists can transform skin cells from someone with the disorder into bone cells and grow them in the lab. These cells will then have the same genetic makeup as that of the original patient, thus creating a ‘disease in a dish.’ We have written often about these models being used for various diseases, particularly neurological ones, but not cancer.

“Our study is among the first to use induced pluripotent stem cells as the foundation of a model for cancer,” said lead author and Mount Sinai postdoctoral fellow Dung-Fang Lee in today’s press release.

The team’s research centered on the protein p53. P53 normally acts as a tumor suppressor, keeping cell divisions in check so as not to divide out of control and morph into early-stage tumors. Previous research had revealed that 70% of people with LFS have a specific mutation in the gene that encodes p53. Using this knowledge and with the help of the iPSC technology, the team shed much-needed light on a molecular link between LFS and bone cancer. According to Lee:

“This model, when combined with a rare genetic disease, revealed for the first time how a protein known to prevent tumor growth in most cases, p53, may instead drive bone cancer when genetic changes cause too much of it to be made in the wrong place.”

Specifically, the team discovered that the ultimate culprit of LFS bone cancer is an overactive p53 gene. Too much p53, it turns out, reduces the amount of another gene, called H19. This then leads to a decrease in the protein decorin. Decorin normally acts to help stem cells mature into healthy, bone-making cells, known as osteoblasts. Without it, the stem cells can’t mature. They instead divide over and over again, out of control, and ultimately cause the growth of dangerous tumors.

But those out of control cells can become a target for therapy, say researchers. In fact, the team found that artificially boosting H19 levels could have a positive effect.

“Our experiments showed that restoring H19 expression hindered by too much p53 restored “protective differentiation” of osteoblasts to counter events of tumor growth early on in bone cancer,” said Lemischka.

And, because mutations in p53 have been linked to other forms of bone cancer, the team is optimistic that these preliminary results will be able to guide treatment for bone cancer patients—whether they have LFS or not. Added Lemischka:

“The work has implications for the future treatment or prevention of LFS-associated osteosarcoma, and possibly for all forms of bone cancer driven by p53 mutations, with H19 and p53 established now as potential targets for future drugs.”

Learn more about how scientists are using stem cell technology to model disease in a dish in our special video series: Stem Cells In Your Face:

Cancer Cells Mimic Blood Vessels to Colonize the Body’s Farthest Reaches

Scientists at Cold Spring Harbor Laboratory have just uncovered the latest dirty trick in the cancer playbook—one that spurs the cancer cells to spread throughout the body and evade treatment. But importantly, they believe they may have found a way to counter it.

Reporting today in the journal Nature, Cold Spring Harbor researchers describe how tumor cells can form tubular networks that mimic blood vessels. It is this mimicry, the team argues, that plays a key role in helping the cancer spread throughout the body—and a significant hurdle to successfully treating the disease.

Two adjacent sections of a mouse breast tumor. Tissue at left is stained so that normal blood vessels can be seen (black arrow). Extending from these vessels are blood filled channels (green arrows). On the right, the tissue is stained for a fluorescent protein expressed by the tumor cells. Here, blood-filled channels are actually formed by tumor cells in a process known as vascular mimicry. [Credit: Hannon Lab, CSHL]

Two adjacent sections of a mouse breast tumor. Tissue at left is stained so that normal blood vessels can be seen (black arrow). Extending from these vessels are blood filled channels (green arrows). On the right, the tissue is stained for a fluorescent protein expressed by the tumor cells. Here, blood-filled channels are actually formed by tumor cells in a process known as vascular mimicry. [Credit: Hannon Lab, CSHL]

Using mouse models of breast cancer, the team—led by Simon Knott—identified this phenomenon, called ‘vascular mimicry,’ and revealed that two genes, called Serpine2 and Slpi, were driving it. Made up of tumor cells literally stacked together, these tubular networks allowed oxygen and other nutrients to reach far-flung tumor cells throughout the body. This kept the tumor cells healthy, and helped them spread.

In today’s press release, Knott explained his initial reactions to this critical discovery:

“It’s very neat to watch and see cells evolve to have these capacities, but on the other hand it’s really scary to think that these cells are sitting there in people doing this.”

In laboratory experiments, the team found that boosting levels of Serpin2 and Slpi boosted the cancer’s ability to build these networks. Conversely, shutting down these two genes appeared to do the opposite. Knott argues that targeting the proteins that these two genes produce, as a way of shutting them off, may be a winning strategy:

“Targeting them might provide therapeutic benefits,” said Knott, “but we’re not sure yet.”

Indeed, research efforts over the past decade or more have tried to curb the production of these tubular networks of tumor cells, but with limited success. These drugs, called angiogenesis inhibitors, may not have worked as well as originally hoped because the underlying mechanism that creates this vascular mimicry—namely the genes Serpin2 and Slpi—was not targeted. Postdoctoral researcher Elvin Wagenblast, the paper’s first author, thinks they might have more success now:

“Maybe by targeting angiogenesis and also vascular mimicry at the same time we might actually have a better benefit in the clinic in the long run.”

This strategy is ultimately the goal of the team, but much work remains. Their most immediate next steps are to understand the process by which tumor cells pass through these tubular networks and infiltrate new areas of the body. But armed with this new-found knowledge of vascular mimicry, these and other researchers may be well on their way to outsmarting cancer, at least some of the time.

Breast Cancer Tumors Recruit Immune Cells to the Dark Side

We rely on our immune system to stave off all classes of disease—but what happens when the very system responsible for keeping us healthy turns to the dark side? In new research published today, scientists uncover new evidence that reveals how breast cancer tumors can actually recruit immune cells to spur the spread of disease.

Some forms of breast cancer tumors can actually turn the body's own immune system against itself.

Some forms of breast cancer tumors can actually turn the body’s own immune system against itself.

Breast cancer is one of the most common cancers, and if caught early, is highly treatable. In fact, the majority of deaths from breast cancer occur because the disease has been caught too late, having already spread to other parts of the body, a process called ‘metastasis.’ Recently, scientists discovered that women who have a heightened number of a particular type of immune cells, called ‘neutrophils,’ in their blood stream have a higher chance of their breast cancer metastasizing to other tissues. But they couldn’t figure out why.

Enter Karin de Visser, and her team at the Netherlands Cancer Institute, who announce today in the journal Nature the precise link between neutrophil immune cells and breast cancer metastasis.

They found that some types of breast tumors are particularly nefarious, sending out signals to the person’s immune system to speed up their production of neutrophils. And then they instruct these newly activated neutrophils to go rogue.

Rather than attack the tumor, these neutrophils turn on the immune system. They especially focus their efforts at blocking T cells—the type of immune cells whose job is normally to target and attack cancer cells. Further examination in mouse models of breast cancer revealed a particular protein, called interleukin 17 (or IL17) played a key role in this process. As Visser explained in today’s news release:

“We saw in our experiments that IL17 is crucial for the increased production of neutrophils. And not only that, it turns out that this is also the molecule that changes the behavior of the neutrophils, causing them to become T cell inhibitory.”

The solution then, was clear: block the connection, or pathway, between IL17 and neutrophils, and you can thwart the tumor’s efforts. And when Visser and her team, including first author and postdoctoral researcher Seth Coffelt, did this they saw a significant improvement. When the IL17-neutrophil pathway was blocked in the mouse models, the tumors failed to spread at the same rate.

“What’s notable is that blocking the IL17-neutrophil route prevented the development of metastases, but did not affect the primary tumor,” Visser added. “So this could be a promising strategy to prevent the tumor from spreading.”

The researchers are cautious about focusing their efforts on blocking neutrophils, however, as these cells are in and of themselves important to stave off infections. A breast cancer patient with neutrophil levels that were too low would be at risk for developing a whole host of infections from dangerous pathogens. As such, the research team argues that focusing on ways to block IL17 is the best option.

Just last month, the FDA approved an anti-IL17 based therapy to treat psoriasis. This therapy, or others like it, could be harnessed to treat aggressive breast cancers. Says Visser:

“It would be very interesting to investigate whether these already existing drugs are beneficial for breast cancer patients. It may be possible to turn these traitors of the immune system back towards the good side and prevent their ability to promote breast cancer metastasis.”