Protein that turns normal cells into cancer stem cells offers target to fight colon cancer

colon-cancer

Colon cancer: Photo courtesy WebMD

Colon cancer is a global killer. Each year more than one million people worldwide are diagnosed with it; more than half a million die from it. If diagnosed early enough the standard treatment involves surgery, chemotherapy, radiation or targeted drug therapy to destroy the tumors. In many cases this may work. But in some cases, while this approach helps put people in remission, eventually the cancer returns, spreads throughout the body, and ultimately proves fatal.

Now researchers may have identified a protein that causes normal cells to become cancerous, and turn into cancer stem cells (CSCs). This discovery could help provide a new target for anti-cancer therapies.

Cancer stem cells are devilishly tricky. While most cancer cells are killed by chemotherapy or other therapies, cancer stem cells are able to lie dormant and hide, then emerge later to grow and spread, causing the person to relapse and the cancer to return.

In a study published in Nature Research’s Scientific Reports, researchers at SU Health New Orleans School of Medicine and Stanley S. Scott Cancer Center identified a protein, called SATB2, that appears to act as an “on/off” switch for specific genes inside a cancer cell.

In normal, healthy colorectal tissue SATB2 is not active, but in colorectal cancer it is highly active, found in around 85 percent of tumors. So, working with mice, the researchers inserted extra copies of the SATB2 gene, which produced more SATB2 protein in normal colorectal tissue. They found that this produced profound changes in the cell, leading to uncontrolled cell growth. In effect it turned a normal cell into a cancer stem cell.

As the researchers state in their paper:

“These data suggest that SATB2 can transform normal colon epithelial cells to CSCs/progenitor-like cells which play significant roles in cancer initiation, promotion and metastasis.”

When the researchers took colorectal cancer cells and inhibited SATB2 they found that this not only suppressed the growth of the cancer and it’s ability to spread, it also prevented those cancer cells from becoming cancer stem cells.

In a news release about the study Dr. Rakesh Srivastava,  the senior author on the paper, said the findings are important:

“Since the SATB2 protein is highly expressed in the colorectal cell lines and tissues, it can be an attractive target for therapy, diagnosis and prognosis.”

Because SATB2 is found in other cancers too, such as breast cancer, these findings may hold significance for more than just colorectal cancer.

The next step is to repeat the study in mice that have been genetically modified to better reflect the way colon cancer shows up in people. The team hope this will not only confirm their findings, but also give them a deeper understanding of the role that SATB2 plays in cancer formation and spread.

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Stem Cell Stories That Caught Our Eye: Three new ways to target cancer stem 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.

Targeting cancer stem cells. This week, three studies came out with novel ways for targeting cancer stem cells in different types of cancers. Here’s a brief run-down of this trifecta of cancer stem cell-crushing stories:

Take your vitamins! Scientists in the UK were experimenting on cancer stem cells and comparing natural substances to on-the-market cancer drugs to determine whether any of the natural substances were effective at disrupting the metabolism (the chemical reactions that keep cells alive and functioning) of cancer stem cells. Interestingly, they found that ascorbic acid, which you’ll know as Vitamin C, was ten times better at curbing cancer stem cell growth compared to a cancer drug called 2-DG.

Vitamin C has popped up as an anti-cancer treatment in the past when Nobel Laureate Linus Pauling found that it dramatically reduced the death rate in breast cancer patients. However this current study is the first to show that Vitamin C has a direct effect on cancer stem cells.

In coverage by ScienceDaily, the UK team hinted at plans to test Vitamin C in clinical trials:

“Vitamin C is cheap, natural, non-toxic and readily available so to have it as a potential weapon in the fight against cancer would be a significant step. Our results indicate it is a promising agent for clinical trials, and a as an add-on to more conventional therapies, to prevent tumour recurrence, further disease progression and metastasis.”

 

A gene called ZEB1 determines how aggressive brain tumors are. A team from Cedars-Sinai Medical Center was interested to know how cancer stem cells in aggressive brain tumors called gliomas survive, reproduce and affect patient survival. In a study published in Scientific Reports, they studied the genetic information of over 4000 brain tumor samples and found ZEB1, a gene that regulates tumor growth and is associated with patient survival.

They found that patients with a healthy copy of the ZEB1 gene had a higher survival rate and less aggressive tumors compared to patients that didn’t have ZEB1 or had a mutated version of the gene.

In coverage by ScienceDaily, the senior author on the study explained how their study’s findings will allow for more personalized treatments for patients with glioma based on whether they have ZEB1 or not:

“Patients without the gene in their tumors have more aggressive cancers that act like stem cells by developing into an uncontrollable number of cell types. This new information could help us to measure the mutation in these patients so that we are able to provide a more accurate prognosis and treatment plan.”

 

Beating resistant tumors by squashing cancer stem cells. Our final cancer stem cell story today comes from the UCLA School of Dentistry. This team is studying another type of aggressive cancer called a squamous cell carcinoma that causes tumors in the head and neck. Often these tumors resist treatment and spread to a patient’s lymph nodes, which quickly reduces their survival rate.

The UCLA team thought that maybe pesky cancer stem cells were to blame for the aggressive and resistant nature of these head and neck tumors. In a study published in Cell Stem Cell, they developed a mouse model of head and neck carcinoma and isolated cancer stem cells from the tumors of these mice. When they studied these stem cells, they found that they expressed unique proteins compared to non-cancer cells. These included Bmi1, a well-known stem cell protein, and AP-1, a transcription factor protein that regulates other cancer genes.

At left, head and neck squamous cell carcinoma invasive growth, and at right, cancer stem cells (shown in red) in head and neck squamous cell carcinoma. (Image Demeng Chen and Cun-Yu Wang/UCLA)

After identifying the culprits, the team developed a new combination strategy that targeted the cancer stem cells while also killing off the tumors using chemotherapy drugs.

In a UCLA Newsroom press release, the lead scientist on the study Dr. Cun-Yu Wang explained the importance of their study for the future treatment of cancer and solid tumors:

“This study shows that for the first time, targeting the proliferating tumor mass and dormant cancer stem cells with combination therapy effectively inhibited tumor growth and prevented metastasis compared to monotherapy in mice. Our discovery could be applied to other solid tumors such as breast and colon cancer, which also frequently metastasizes to lymph nodes or distant organs.”

Stem Cell Profiles in Courage: Karl’s Fight with Cancer

Karl Trede

Karl Trede

When I think of a pioneer I have an image in my head of people heading west across the Americans plains in the 18th century, riding in a covered wagon pulled by weary oxen.

Karl Trede doesn’t fit that image at all. He is a trim, elegant man who has a ready smile and a fondness for Hawaiian shirts. But he is no less a pioneer for all that. That’s why we profiled him in our 2016 Annual Report.

In 2006 Karl was diagnosed with cancer of the throat. He underwent surgery to remove his vocal chords and thought he had beaten the cancer. A few years later, it came back. That was when Karl became the first person ever treated in a CIRM-funded clinical trial testing a new anti-tumor therapy targeting cancer stem cells that so far has helped hold the disease at bay.

Here is Karl’s story, in his own words:

“I had some follow-up tests and those showed spots in my lungs. Over the course of several years, they saw those spots grow, and we knew the cancer had spread to my lungs. I went to Stanford and was told there was no effective treatment for it, fortunately it was slow growing.

Then one day they said we have a new clinical trial we’re going to start would you be interested in being part of it.

I don’t believe I knew at the time that I was going to be the first one in the trial [now that’s what I call a pioneer] but I thought I’d give it a whirl and I said ‘Sure’. I wasn’t real concerned about being the first in a trial never tested in people before. I figured I was going to have to go someday so I guess if I was the first person and something really went wrong then they’d definitely learn something; so, to me, that was kind of worth my time.

Fortunately, I lasted 13 months, 72 treatments with absolutely no side effects. I consider myself really lucky to have been a part of it.

It was an experience for me, it was eye opening. I got an IV infusion, and the whole process was 4 hours once a week.

Dr. Sikic (the Stanford doctor who oversees the clinical trial) made it a practice of staying in the room with me when I was getting my treatments because they’d never tried it in people, they’d tested it in mice, but hadn’t tested it in people and wanted to make sure they were safe and nothing bad happened.

The main goals of the trial were to define what the side effects were and what the right dose is and they got both of those. So I feel privileged to have been a part of this.

My wife and I (Vita) have four boys. They’re spread out now – two in the San Francisco Bay Area, one in Oregon and one in Nevada. But we like to get together a few times a year. They’re all good cooks, so when we have a family get together there’s a lot of cooking involved.

The Saturday after Thanksgiving, in 2015, the boys decided they wanted to have a rib cook-off for up to around 30 people and I can proudly say that I kicked their ass on the rib cook-off. I have an electric cooker and I just cook ‘em slow and long. I do a cranberry sauce, just some home made bbq sauces

I’m a beef guy, I love a good steak, a good ribeye or prime rib, I make a pretty mean Oso bucco, I make a good spaghetti sauce, baked chicken with an asparagus mousse that is pretty good.

I just consider myself a lucky guy.”

Karl Trede with CIRM President Randy Mills at the 2016 December Board meeting.

Karl Trede with CIRM President Randy Mills at the 2016 December Board meeting.


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Stem cell stories that caught our eye: a surprising benefit of fasting, faster way to make iPSCs, unlocking the secret of leukemia cancer 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.

Fasting

Is fasting the fountain of youth?

Among the many insults our bodies endure in old age is a weakened immune system which leaves the elderly more susceptible to infection. Chemotherapy patients also face the same predicament due to the immune suppressing effects of their toxic anticancer treatments. While many researchers aim to develop drugs or cell therapies to protect the immune system, a University of Southern California research report this week suggests an effective alternative intervention that’s startlingly straightforward: fasting for 72 hours.

The study published in Cell Stem Cell showed that cycles of prolonged fasting in older mice led to a decrease in white blood cells which in turn set off a regenerative burst of blood stem cells. This restart of the blood stem cells replenished the immune system with new white blood cells. In a pilot Phase 1 clinical trial, cancer patients who fasted 72 hours before receiving chemotherapy maintained normal levels of white blood cells.

A look at the molecular level of the process pointed to a decrease in the levels of a protein called PKA in stem cells during the fasting period. In a university press release carried by Science Daily, the study leader, Valter Longo, explained the significance of this finding:

“PKA is the key gene that needs to shut down in order for these stem cells to switch into regenerative mode. It gives the ‘okay’ for stem cells to go ahead and begin proliferating and rebuild the entire system. And the good news is that the body got rid of the parts of the system that might be damaged or old, the inefficient parts, during the fasting. Now, if you start with a system heavily damaged by chemotherapy or aging, fasting cycles can generate, literally, a new immune system.”

In additional to necessary follow up studies, the team is looking into whether fasting could benefit other organ systems besides the immune system. If the data holds up, it could be that regular fasting or direct targeting of PKA could put us on the road to a much more graceful and healthier aging process.

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Faster, cheaper, safer way to use iPS cells

Science, like traffic in any major city, never moves quite as quickly as you would like, but now Japanese researchers are teaming up to develop a faster, and cheaper way of using iPSC’s , pluripotent stem cells that are reprogrammed from adult cells, for transplants.

Part of the beauty of iPSCs is that because those cells came from the patient themselves, there is less risk of rejection. But there are problems with this method. Taking adult cells and turning them into enough cells to treat someone can take a long time. It’s expensive too.

But now researchers at Kyoto University and three other institutions in Japan have announced they are teaming up to change that. They want to create a stockpile of iPSCs that are resistant to immunological rejection, and are ready to be shipped out to researchers.

Having a stockpile of ready-to-use iPSCs on hand means researchers won’t have to wait months to develop their own, so they can speed up their work.

Shinya Yamanaka, who developed the technique to create iPSCs and won the Nobel prize for his efforts, say there’s another advantage with this collaboration. In a news article on Nikkei’s Asian Review he said these cells will have been screened to make sure they don’t carry any potentially cancer-causing mutations.

“We will take all possible measures to look into the safety in each case, and we’ll give the green light once we’ve determined they are sound scientifically. If there is any concern at all, we will put a stop to it.”

CIRM is already working towards a similar goal with our iPSC Initiative.

Unlocking the secrets of leukemia stem cells

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Zombies: courtesy “The Walking Dead”

Any article that has an opening sentence that says “Cancer stem cells are like zombies” has to be worth reading. And a report in ScienceMag  that explains how pre-leukemia white blood cell precursors become leukemia cancer stem cells is definitely worth reading.

The article is about a study in the journal Cell Stem Cell by researchers at UC San Diego. The senior author is Catriona Jamieson:

“In this study, we showed that cancer stem cells co-opt an RNA editing system to clone themselves. What’s more, we found a method to dial it down.”

An enzyme called ADAR1 is known to spur cancer growth by manipulating small pieces of genetic material known as microRNA. Jamieson and her team wanted to track how that was done. They discovered it is a cascade of events, and that once the first step is taken a series of others quickly followed on.

They found that when white blood cells have a genetic mutation that is linked to leukemia, they are prone to inflammation. That inflammation then activates ADAR1, which in turn slows down a segment of microRNA called let-7 resulting in increased cell growth. The end result is that the white blood cells that began this cascade become leukemia stem cells and spread an aggressive and frequently treatment-resistant form of the blood cancer.

Having uncovered how ADAR1 works Jamieson and her team then tried to find a way to stop it. They discovered that by blocking the white blood cells susceptibility to inflammation, they could prevent the cascade from even starting. They also found that by using a compound called 8-Aza they could impede ADAR1’s ability to stimulate cell growth by around 40 percent.

Jamieson

Catriona Jamieson – definitely not a zombie

Jamieson says the findings open up all sorts of possibilities:

“Based on this research, we believe that detecting ADAR1 activity will be important for predicting cancer progression. In addition, inhibiting this enzyme represents a unique therapeutic vulnerability in cancer stem cells with active inflammatory signaling that may respond to pharmacologic inhibitors of inflammation sensitivity or selective ADAR1 inhibitors that are currently being developed.”

This wasn’t a CIRM-funded study but we have supported other projects by Dr. Jamieson that have led to clinical trials.

 

 

 

 

Stem cell stories that caught our eye: fighting cancer, a cell’s neighborhood matters, funding next generation scientists

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.

Reprogramming skin to fight cancer. Earlier CIRM-funded research showed that adult nerve stem cells can home to the residual brain cancer left behind after surgery and deliver a cancer killing agent directly to where it is most needed. Now a team at the University of North Carolina has shown it can use reprogramming techniques similar to the Nobel-prize winning iPS cell reprogramming method to turn a patient’s own skin cells directly into adult nerve stem cells. They then used those stem cells to deliver a cancer-fighting protein to mice with brain cancer and extended their lives.

“We wanted to find out if these induced neural stem cells would home in on cancer cells and whether they could be used to deliver a therapeutic agent. This is the first time this direct reprogramming technology has been used to treat cancer,” said the leader of the study, Shawn Hingtgen, in a UNC press release.

Cancer cells. (iStockPhoto)

Cancer cells. (iStockPhoto)

Many outlets picked up the release, including FoxNews, which overstated the lack of progress in the field.  Their piece suggests there had been no improvements “in more than 30 years,” which ignores several advances, but you can not argue with the quote they use from Hingtgen: “Patients desperately need a better standard of care.”

More evidence the neighborhood matters. Cells excrete substances that become the structure, known as the extracellular matrix (ECM), that holds them in place. Many regenerative medicine strategies count on using donor ECM to attract and hold stem cells, or use a synthetic material that mimics ECM. A team at the Institute for Research in Biomedicine in Barcelona has documented a strong feedback loop in which the ECM also directs which cells populate an area.

The work builds on a growing body of research we have written about that shows the neighborhood a stem cell finds itself in helps dictate what it will become. The study, published in eLife, focused on the tracheal tube in fruit flies.

“The biological context of these cells modifies not only their behavior but also their internal structure,” said the head of the project Jordi Casanova in a press release picked up by NewsMedical.net. “When we modify only the extracellular matrix, the cytoskeleton is also altered.”

The research team suggested that this form of intracellular communication has been preserved in evolution and has an important role in humans, including in inflammatory diseases and cancer.

Cancer therapys major step toward patients. We frequently point out that our mission is not to do research; it is to deliver therapies to patients. And that requires commercial partners that can do all the late stage work needed to bring a therapy to market. So, we are thrilled when the developers of a therapy we have fostered from the very earliest days in the lab announces they have complete the first half of a $75 million round of venture financing, and with major names from Silicon Valley, Lightspeed, Sutter Hill and Google Ventures.

The therapy, from the Stanford Lab of Irv Weissman, now being taken forward by the company he and colleagues founded, Forty Seven, has been shown to be effective against several types of cancer in animals and is now in an early phase human clinical trial funded by CIRM. We also funded the pre-clinical work for a total investment of more than $30 million in the therapy, which has promise to work synergistically with other therapies to wipe out notoriously difficult cancers. The company name comes from the therapy’s target on cancer stem cells, CD47.

Irv Weissman

Irv Weissman

“Targeting CD47 integrates the adaptive and innate immune systems, creating synergy with existing cancer-specific antibodies like rituximab, cetuximab and trastuzumab through ADCP, and potentially with T-cell checkpoint inhibitors through cross-presentation,” said Weissman in a company press release.

The online publication Xconomy wrote a longer piece providing more perspective on how the therapy could fit into the market and on CIRM’s role in its development.

The next generation in the lab.  The Guardsman, the student newspaper of City College, San Francisco, did a nice write up on our recent renewal of the colleges grant for one of our 17 current Bridges programs that train undergraduate and masters level students the ins-and-outs of working in a stem cell laboratory.

Rosa Canchari works with cell cultures in City College’s biotech laboratory. (Photo by Amanda Aceves/Special to The Guardsman)

Rosa Canchari works with cell cultures in City College’s biotech laboratory. (Photo by Amanda Aceves/Special to The Guardsman)

The current renewal has redirected the programs to have the students better understand the end user, the patient, and to get a firmer grasp on the regulatory and process development pathways needed to bring a new therapy to market. As program officer for this initiative, I will be meeting with all the program directors next week to discuss how best to implement these changes.

But, as the CCSF director Dr. Carin Zimmerman told the Guardsman, the program continues to generate highly valued skilled workers. Like many of our programs, CCSF offers its basic courses to students at the school beyond those enrolled in the CIRM internships, and even that more limited exposure to stem cell science often lands jobs.

“One of the reasons we have a hard time filling all these classes is because people take one or two classes and get hired,” said Carin Zimmerman.

New drug kicks the cancer stem cell addiction

Did you know that cancer stem cells have an addiction problem? This might sound bizarre, but the science checks out.

Cancer stem cells are found in many different types of cancer tumors. They have the uncanny ability to survive even the most aggressive forms of treatment. After weathering the storm, cancer stem cells are able to divide and repopulate an entire tumor and even take road trips to create tumors in other areas of the body.

How cancer stem cells are able to survive and thrive is a question that is being actively pursued by scientists who aim to develop new strategies that target these cells.

Cancer stem cells have a Wnt addiction

To understand why a cancer stem cell is so good at staying alive and creating new tumors, you need to get down to the protein signaling level, which is basically a cascade of protein interactions that begin at the cell surface and instruct certain activities inside the cell. During embryonic development, one of the signaling pathways that’s activated is the Wnt pathway. It’s responsible for keeping embryonic stem cells in a pluripotent state where they maintain the ability to become any cell type.

As embryonic stem cells mature into adult cells, Wnt signaling plays different roles. It helps stem cells differentiate or change into cells of various tissues and helps maintain the health and integrity of those tissues. Because Wnt signaling has varying functions depending on the developmental stage of the cells, it’s important for cells to properly regulate this pathway.

It turns out that cancer stem cells don’t do this. Typically cells need to receive certain biochemical signals to activate the Wnt pathway, but cancer stem cells acquire genetic mutations and evolve such that this pathway is constantly activated. They ramp up their Wnt signaling and never turn it off. This “Wnt addiction” allows them to stay alive and flourish in a cancerous stem cell state.

Kicking the Wnt Addiction

A team at the Max Delbruck Center (MDC) in Germany decided to kick this Wnt addiction and make cancer stem cells go cold turkey. They published their results in the journal Cancer Research this week.

Their strategy involved targeting proteins called transcription factors, the activators of genes, that are turned on during aberrant Wnt signaling in cancer stem cells. The transcription factor they focused on is called TCF4. In normal cells, biochemical signals are required to activate the Wnt cascade and a protein called beta-catenin, which transmits signals to transcription factors like TCF4 that then turn on genes. In cancer stem cells, this signal isn’t required because the Wnt pathway is permanently switched on leaving TCF4 free to activate genes that promote tumor cell survival and growth.

The researchers thought that if they could break up the partnership between beta-catenin and TCF4, that they might be able to block Wnt signaling and kill the life-line of the cancer stem cells. They screened a library of drugs and identified a small molecule called LF3 that was able to block the interaction between beta-catenin and TCF4.

A new drug kills that cancer stem cells. The image on the left shows beta catenin (red) in cell nuclei indicating that these are cancer stem cells. The image on the right shows that the new substance sucessfully removed beta catenin from the nuclei. Picture by Liang Fang for the MDC

Cancer stem cells express beta-catenin shown in red on the left. On the right, drug treatment blocks Wnt signaling and removes beta-catenin from the cancer stem cells. (Image: Liang Fang for the MDC)

The scientists tested the LF3 molecule in mice with tumors derived from human colon cancer stem cells. Senior author on the study, Walter Birchmeier, explained in an MDC press release:

Walter

Walter Birchmeier

“We observed a strong reduction of tumor growth. What remained of the tumors seemed to be devoid of cancer stem cells – LF3 seemed to be powerfully triggering these cells to differentiate into benign tissue. At the same time, no signaling systems other than Wnt were disturbed. All of these factors make LF3 very promising to further develop as a lead compound, aiming for therapies that target human tumors whose growth and survival depend on Wnt signaling.”

Upon further analysis, they found that LF3 prevented cancer stem cells from dividing into more stem cells and migrating to other tissues. Instead, they differentiated into non-cancerous tissues. Importantly, the drug did not negatively affect the function of healthy cells nearby. This is a logical concern as Wnt signaling is activated in healthy adult tissue, just in a different way than in stem cells.

This study offers a new angle for cancer treatment. Not only does LF3 force cancer stem cells to kick their “Wnt addiction”, it also spares healthy cells and tissues. This drug sounds like a promising option for patients who suffer from aggressive, recurring tumors caused by cancer stem cells.


 

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Using baking ingredient to create “nano” bombs and destroy cancer stem cells

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“I am not a cook”. Richard Nixon and the baking ingredient that could help win the “war on cancer”

In 1971 President Richard Nixon declared a “war on cancer” and signed the National Cancer Act into law. Forty years later we’re still waging that war, and cancer is still one of the leading causes of death. But now researchers in Ohio have unveiled a new weapon; a nanobomb that targets cancer stem cells.

In treating invasive cancers the standard weapons are chemotherapy and radiation, but cancer stem cells are somehow able to evade these and lie dormant. Eventually they emerge from hiding and multiply and spread throughout the body, leading to a recurrence of the cancer.

So researchers at The Ohio State University Comprehensive Cancer Center turned to nanoparticles to try and target them. Nanoparticles for those of who aren’t up on the latest trendy science topics (something I plead guilty to) are particles between 1 and 100 nanometers in size. Just to put it in context, that’s about one billionth of a meter. In other words, very small indeed.

In the past when scientists tried to use nanoparticles to carry anti-cancer therapies such as therapeutic RNA to the tumor, the cancer cells simply enfolded the RNA nanoparticles in a kind of compartment called an endosome, which rendered them useless.

In a news release, principal investigator Xiaoming He said their new approach helps the nanoparticles escape from the endosomes and attack the cancer:

“We believe we’ve overcome this challenge by developing nanoparticles that include ammonium bicarbonate, a small molecule that vaporizes when exposing the nanoparticles to near-infrared laser light, causing the nanoparticle and endosome to burst, releasing the therapeutic RNA.”

In the study, published in Advanced Materials,   He and his team put micro-RNA miR-34a inside the nanoparticles. This is a molecule known to lower the levels of a  protein that cancer stem cells need for survival. When the ammonium bicarbonate was hit with the near-infrared laser it caused the endosomes to burst and released the miR-34a, killing the cancer cell.

When they tested this approach in a mouse model of human prostate cancer it significantly reduced the size of the tumors.

Because near-infrared lasers penetrate to about half an inch this method could be used for tumors near the skin surface, and for deeper ones would only require a minimally invasive surgery to deliver the necessary dose of light.

Ammonium bicarbonate, the ingredient used to help the nanoparticles swell up, is used by the food industry for some baked goods such as cookies and crackers. It’s a little odd to think that something used in such tasty treats could also be potentially deadly – think about that next time you are browsing the cookie aisle at the supermarket.

 

 

 

 

 

 

 

 

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

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

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

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

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

Attacking the cancer

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

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

Recruiting the patients

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

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

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

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

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

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


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

On the Academic Side

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

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

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

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

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

On the Industry Side

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

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

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

 

Big Picture

the boot

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

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


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