New target for defeating breast cancer stem cells uncovered

Stashed away in most of your tissues and organs lie small populations of adult stem cells. They help keep our bodies functioning properly by replenishing dying or damaged cells. Their ability to make more copies of themselves, as needed, ensures that there’s always an adequate supply set aside. But this very same self-renewing, life-sustaining property of adult stem cells is deadly in the hands of cancer stem cells. Also called tumor-initiating cells, cancer stem cells sustain tumor growth even after chemotherapy and are thought to be a primary cause of cancer relapse.

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Microscopic image of normal mouse mammary ducts. Mammary stem cells are found among basal cells (green). Image courtesy of Toni Celià-Terrassa and Yibin Kang, Princeton University

By studying adult and cancer stem cells side-by-side, Princeton researchers report this week in Nature Cell Biology that they’ve uncovered a common function in both cells types that not only helps explain an adult stem cell’s self-renewing ability but also points to new therapeutic approaches to targeting breast cancer stem cells.

Both adult and cancer stem cells continually resist signals from their environment that encourage them to specialize, or differentiate, into a particular cell type. Once specialized, the cells lose their ability to self-renew and will eventually die off. Now, if all the adult stem cells in an organ followed that instruction, they would eventually become depleted and the organ would lose the ability to repair itself. The same holds true for cancer stem cells which actually would be a good thing since it would lead to the tumor’s death.

The Princeton team first identified a molecule called miR-199a that allows mammary (breast) stem cells to resist differentiation signals by directly blocking the production of a protein called LCOR. Artificially boosting the amount of miR-199a led to a decrease in LCOR levels and an increase in stem cell function. But when LCOR levels were increased, mammary stem cell function was restricted.

The researchers then turned their attention to breast cancer stem cells and found the same miR-199a/LCOR function at work. In a similar fashion, boosting miR-199a levels enhanced cancer stem cell function and increased tumor formation while increasing LCOR restricted the tumor-forming ability of the breast cancer stem cells.

These lab results also matched up with tissue samples taken from breast cancer patients. High miR-199a levels in the samples correlated with low patient survival rates. But those with high levels of LCOR showed a better prognosis.

It turns out that cells in our immune system are responsible for boosting LCOR in mammary and breast cancer stem cells by releasing a protein called interferon alpha. So the presence of interferon alpha nudges mammary stem cells to mature into mammary gland cells and inhibits breast cancer stems from forming tumors. But in the presence of elevated miR-199a levels, mammary and breast cancer stem cells are protected and maintain their numbers by deactivating the interferon alpha/LCOR signal.

If you’re still with me, these results point to miR-199a as a promising target for restoring interferon-alpha’s cancer interfering properties. Team leader Dr. Yibin Kang highlighted this possibility in a Princeton University press release:

“Interferons have been widely used for the treatment of multiple cancer types. These treatments might become more effective if the interferon-resistant cancer stem cells can be rendered sensitive by targeting the miR-199a-LCOR pathway.”

Stem cell stories that caught our eye: better ovarian cancer drugs, creating inner ear tissue, small fish big splash

Two drugs are better than one for ovarian cancer (Karen Ring). Earlier this week, scientists from UCLA reported that a combination drug therapy could be an effective treatment for 50% of aggressive ovarian cancers. The study was published in the journal Precision Oncology and was led by Dr. Sanaz Memarzadeh.

Women with high-grade ovarian tumors have an 85% chance of tumor recurrence after treatment with a common chemotherapy drug called carboplatin. The UCLA team found in a previous study that ovarian cancer stem cells are to blame because they are resistant to carboplatin. It’s because these stem cells have an abundance of proteins called cIAPs, which prevent cell death from chemotherapy.

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Ovarian cancer cells (blue) expressing cIAP protein (red) on the left are more sensitive to a combination therapy than cancer cells that don’t express the protein on the right. (UCLA Broad Stem Cell Research Center/Precision Oncology)

Memarzadeh discovered that an experimental drug called birinapant made some ovarian cancer tumors more sensitive to chemotherapy treatment by breaking down cIAPs. This gave her the idea that combining the two drugs, birinapant and carboplatin, might be a more effective strategy for treating aggressive ovarian tumors.

By treating with the two drugs simultaneously, the scientists improved the survival rate of mice with ovarian cancer. They also tested this combo drug treatment on 23 ovarian cancer cell lines derived from women with highly aggressive tumors. The treatment killed off half of the cell lines indicating that some forms of this cancer are resistant to the combination treatment.

When they measured the levels of cIAPs in the human ovarian cancer cell lines, they found that high levels of the proteins were associated with ovarian tumor cells that responded well to the combination treatment. This is exciting because it means that clinicians can analyze tumor biopsies for cIAP levels to determine whether certain ovarian tumors would respond well to combination therapy.

Memarzadeh shared her plans for future research in a UCLA news release,

“I believe that our research potentially points to a new treatment option. In the near future, I hope to initiate a phase 1/2 clinical trial for women with ovarian cancer tumors predicted to benefit from this combination therapy.”

In a first, researchers create inner ear tissue. From heart muscle to brain cells to insulin-producing cells, researchers have figured out how to make a long list of different human cell types using induced pluripotent stem cells (iPSCs) – cells taken from the body and reprogrammed into a stem cell-like state.

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Human inner ear organoid with sensory hair cells (cyan) and sensory neurons (yellow). An antibody for the protein CTBP2 reveals cell nuclei as well as synapses between hair cells and neurons (magenta). | Photo: Karl Koehler

This week, a research group at the Indiana University School of Medicine successfully added inner ear cells to that list. This feat, published in Nature Biotechnology, is especially important given the fact that the inner ear is one of the few parts of the body that cannot be biopsied for further examination. With these cells in hands, new insights into the causes of hearing loss and balance disorders may be on the horizon.

The inner ear contains 75,000 sensory hair cells that convert sound waves into electrical signals to the brain. Loud noises, drug toxicity, and genetic mutations can permanently damage the hair cells leading to hearing loss and dizziness. Over 15%  of the U.S. population have some form of hearing loss and that number swells to 67% for people over 75.

Due to the complex shape of the inner ear, the team grew the iPSCs into three dimensional balls of cells rather than growing them as a flat layer of cells on a petri dish. With educated guesses sprinkled in with some trial and error, the scientists, for the time, identified a recipe of proteins that stimulated the iPSCs to transform into inner ear tissue. And like any great recipe, it wasn’t so much the ingredient list but the timing that was key:

“If you apply these signals at the wrong time you can potentially generate a brain instead of an inner ear,” first author Dr. Karl Koehler said in an interview with Gizmodo. “The real breakthrough is that we figured out the exact timing to do each one of these [protein] treatments.”

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Senior author, Eri Hashino, Ph.D., and first author, Karl R. Koehler, Ph.D. Photo: Indiana University

Careful examination shows that the tissue, referred to as organoids, not only contained the sensory hair cells of the inner ear cell but also nerve cells, or neurons, that are responsible for relaying the sound waves to the brain. Koehler explained the importance of this result in a press release:

“We also found neurons, like those that transmit signals from the ear to the brain, forming connections with sensory cells. This is an exciting feature of these organoids because both cell types are critical for proper hearing and balance.”

Though it’s still early days, these iPSC-derived inner ear organoids are a key step toward the ultimate goal of repairing hearing loss. Senior author, Dr. Eri Hashino, talked about the team’s approach to reach that goal:

“Up until now, potential drugs or therapies have been tested on animal cells, which often behave differently from human cells. We hope to discover new drugs capable of helping regenerate the sound-sending hair cells in the inner ear of those who have severe hearing problems.”

This man’s research is no fish tale
And finally, we leave you this week with a cool article and video by STAT. It features Dr. Leonard Zon of Harvard University and his many, many tanks full of zebrafish. This little fish has made a huge splash in understanding human development and disease. But don’t take my word for it, watch the video!

Newest member of CIRM Board is a fan of horses, Star Trek and Harry Potter – oh, and she just happens to be a brilliant cancer researcher too.

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An addition to the family is always a cause for celebration, whether it be a new baby, a puppy, or, in our case, a new Board member. That’s why we are delighted to welcome City of Hope’s Linda Malkas, Ph.D., as the newest member of the CIRM Board.

Dr. Malkas has a number of titles including Professor of Molecular and Cellular Biology at Beckman Research Institute; Deputy Director of Basic Research, Comprehensive Cancer Center, City of Hope; and joint head of the Molecular Oncology Program at the Cancer Center.

Her research focus is cancer and she has a pretty impressive track record in the areas of human cell DNA replication/repair, cancer cell biomarker and therapeutic target discovery. As evidence of that, she discovered a molecule that can inhibit certain activities in cancerous cells and hopes to move that into clinical trials in the near future.

California Treasure John Chiang made the appointment saying Dr. Malkas is “extraordinarily well qualified” for the role. It’s hard to disagree. She has a pretty impressive resume:

  • She served for five years on a National Cancer Institute (NCI) subcommittee reviewing cancer center designations.
  • She has served as chair on several NCI study panels and recently took on an advisory role on drug approval policy with the Food and Drug Administration.
  • She has published more than 75 peer-reviewed articles
  • She sits on the editorial boards of several high profile medical journals.

In a news release Dr. Malkas says she’s honored to be chosen to be on the Board:

“The research and technologies developed through this agency has benefited the health of not only Californians but the nation and world itself. I am excited to see what the future holds for the work of this agency.”

With all this in her work life it’s hard to imagine she has time for a life outside of the lab, and yet she does. She has four horses that she loves to ride – not all at the same time we hope – a family, friends, dogs and cats she likes spending time with. And as if that wasn’t enough to make you want to get to know her, she’s a huge fan of Star Trek, vintage sci-fi movies and Harry Potter.

Now that’s what I call a well-rounded individual. We are delighted to have her join the CIRM Team and look forward to getting her views on who are the greater villains, Klingons or Death Eaters.

 

Don’t Be Afraid: High school stem cell researcher on inspiring girls to pursue STEM careers

As part of our CIRM scholar blog series, we’re featuring the research and career accomplishments of CIRM funded students.

Shannon Larsuel

Shannon Larsuel is a high school senior at Mayfield Senior School in Pasadena California. Last summer, she participated in Stanford’s CIRM SPARK high school internship program and did stem cell research in a lab that studies leukemia, a type of blood cancer. Shannon is passionate about helping people through research and medicine and wants to become a pediatric oncologist. She is also dedicated to inspiring young girls to pursue STEM (Science, Technology, Engineering, and Mathematics) careers through a group called the Stem Sisterhood.

I spoke with Shannon to learn more about her involvement in the Stem Sisterhood and her experience in the CIRM SPARK program. Her interview is below.


Q: What is the Stem Sisterhood and how did you get involved?

SL: The Stem Sisterhood is a blog. But for me, it’s more than a blog. It’s a collective of women and scientists that are working to inspire other young scientists who are girls to get involved in the STEM field. I think it’s a wonderful idea because girls are underrepresented in STEM fields, and I think that this needs to change.

I got involved in the Stem Sisterhood because my friend Bridget Garrity is the founder. This past summer when I was at Stanford, I saw that she was doing research at Caltech. I reconnected with her and we started talking about our summer experiences working in labs. Then she asked me if I wanted to be involved in the Stem Sisterhood and be one of the faces on her website. She took an archival photo of Albert Einstein with a group of other scientists that’s on display at Caltech and recreated it with a bunch of young women who were involved in the STEM field. So I said yes to being in the photo, and I’m also in the midst of writing a blog post about my experience at Stanford in the SPARK program.

Members of The Stem Sisterhood

Q: What does the Stem Sisterhood do?

SL: Members of the team go to elementary schools and girl scout troop events and speak about science and STEM to the young girls. The goal is to inspire them to become interested in science and to teach them about different aspects of science that maybe are not that well known.

The Stem Sisterhood is based in Los Angeles. The founder Bridget wants to expand the group, but so far, she has only done local events because she is a senior in high school. The Stem Sisterhood has an Instagram account in addition to their blog. The blog is really interesting and features interviews with women who are in science and STEM careers.

Q: How has the Stem Sisterhood impacted your life?

SL: It has inspired me to reach out to younger girls more about science. It’s something that I am passionate about, and I’d like to pursue a career in the medical field. This group has given me an outlet to share that passion with others and to hopefully change the face of the STEM world.

Q: How did you find out about the CIRM SPARK program?

SL: I knew I wanted to do a science program over the summer, but I wasn’t sure what type. I didn’t know if I wanted to do research or be in a hospital. I googled science programs for high school seniors, and I saw the one at Stanford University. It looked interesting and Stanford is obviously a great institution. Coming from LA, I was nervous that I wouldn’t be able to get in because the program had said it was mostly directed towards students living in the Bay Area. But I got in and I was thrilled. So that’s basically how I heard about it, because I googled and found it.

Q: What was your SPARK experience like?

SL: My program was incredible. I was a little bit nervous and scared going into it because I was the only high school student in my lab. As a high school junior going into senior year, I was worried about being the youngest, and I knew the least about the material that everyone in the lab was researching. But my fears were quickly put aside when I got to the lab. Everyone was kind and helpful, and they were always willing to answer my questions. Overall it was really amazing to have my first lab experience be at Stanford doing research that’s going to potentially change the world.

Shannon working in the lab at Stanford.

I was in a lab that was using stem cells to characterize a type of leukemia. The lab is hoping to study leukemia in vitro and in vivo and potentially create different treatments and cures from this research. It was so cool knowing that I was doing research that was potentially helping to save lives. I also learned how to work with stem cells which was really exciting. Stem cells are a new advancement in the science world, so being able to work with them was incredible to me. So many students will never have that opportunity, and being only 17 at the time, it was amazing that I was working with actual stem cells.

I also liked that the Stanford SPARK program allowed me to see other aspects of the medical world. We did outreach programs in the Stanford community and helped out at the blood drive where we recruited people for the bone marrow registry. I never really knew anything about the registry, but after learning about it, it really interested me. I actually signed up for it when I turned 18. We also met with patients and their families and heard their stories about how stem cell transplants changed their lives. That was so inspiring to me.

Going into the program, I was pretty sure I wanted to be a pediatric oncologist, but after the program, I knew for sure that’s what I wanted to do. I never thought about the research side of pediatric oncology, I only thought about the treatment of patients. So the SPARK program showed me what laboratory research is like, and now that’s something I want to incorporate into my career as a pediatric oncologist.

I learned so much in such a short time period. Through SPARK, I was also able to connect with so many incredible, inspired young people. The students in my program and I still have a group chat, and we text each other about college and what’s new with our lives. It’s nice knowing that there are so many great people out there who share my interests and who are going to change the world.

Stanford SPARK students.

Q: What was your favorite part of the SPARK program?

SL: Being in the lab every day was really incredible to me. It was my first research experience and I was in charge of a semi-independent project where I would do bacterial transformations on my own and run the gels. It was cool that I could do these experiments on my own. I also really loved the end of the summer poster session where all the students from the different SPARK programs came together to present their research. Being in the Stanford program, I only knew the Stanford students, but there were so many other awesome projects that the other SPARK students were doing. I really enjoyed being able to connect with those students as well and learn about their projects.

Q: Why do you want to pursue pediatric oncology?

SL: I’ve always been interested in the medical field but I’ve had a couple of experiences that really inspired me to become a doctor. My friend has a charity that raises money for Children’s Hospital Los Angeles. Every year, we deliver toys to the hospital. The first year I participated, we went to the hospital’s oncology unit and something about it stuck with me. There was one little boy who was getting his chemotherapy treatment. He was probably two years old and he really inspired to create more effective treatments for him and other children.

I also participated in the STEAM Inquiry program at my high school, where I spent two years reading tons of peer reviewed research on immunotherapy for pediatric cancer. Immunotherapy is something that really interests me. It makes sense that since cancer is usually caused by your body’s own mutations, we should be able to use the body’s immune system that normally regulates this to try and cure cancer. This program really inspired me to go into this field to learn more about how we can really tailor the immune system to fight cancer.

Q: What advice do you have for young girls interested in STEM.

SL: My advice is don’t be afraid. I think that sometimes girls are expected to be interested in less intellectual careers. This perception can strike fear into girls and make them think “I won’t be good enough. I’m not smart enough for this.” This kind of thinking is not good at all. So I would say don’t be afraid and be willing to put yourself out there. I know for me, sometimes it’s scary to try something and know you could fail. But that’s the best way to learn. Girls need to know that they are capable of doing anything and if they just try, they will be surprised with what they can do.

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 stories that caught our eye: drug safety for heart cells, worms hijack plant stem cells & battling esophageal cancer

Devising a drug safety measuring stick in stem cell-derived heart muscle cells
One of the mantras in the drug development business is “fail early”. That’s because most of the costs of getting a therapy to market occur at the later stages when an experimental treatment is tested in clinical trials in people. So, it’s best for a company’s bottom line and, more importantly, for patient safety to figure out sooner rather than later if a therapy has dangerous toxic side effects.

Researchers at Stanford reported this week in Science Translational Medicine on a method they devised that could help weed out cancer drugs with toxic effects on the heart before the treatment is tested in people.

In the lab, the team grew beating heart muscle cells, or cardiomyocytes, from induced pluripotent stem cells derived from both healthy volunteers and kidney cancer patients. A set of cancer drugs called tyrosine kinase inhibitors which are known to have a range of serious side effects on the heart, were added to the cells. The effect of the drugs on the heart cell function were measured with several different tests which the scientists combined into a single “safety index”.

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A single human induced pluripotent stem cell-derived cardiomyocyte. Cells such as these were used to assess tyrosine kinase inhibitors for cardiotoxicity in a high-throughput fashion. Credit: Dr. Arun Sharma at Dr. Joseph Wu’s laboratory at Stanford University

They found that the drugs previously shown to have toxic effects on patients’ hearts had the worst safety index values in the current study. And because these cells were in a lab dish and not in a person’s heart, the team was able to carefully examine cell activity and discovered that the toxic effects of three drugs could be alleviated by also adding insulin to the cells.

As lead author Joseph Wu, director of the Stanford Cardiovascular Institute, mentions in a press release, the development of this drug safety index could provide a powerful means to streamline the drug development process and make the drugs safer:

“This type of study represents a critical step forward from the usual process running from initial drug discovery and clinical trials in human patients. It will help pharmaceutical companies better focus their efforts on developing safer drugs, and it will provide patients more effective drugs with fewer side effects”

Worm feeds off of plants by taking control of their stem cells
In what sounds like a bizarre mashup of a vampire movie with a gardening show, a study reported this week pinpoints how worms infiltrate plants by commandeering the plants’ own stem cells. Cyst nematodes are microscopic roundworms that invade and kill soybean plants by sucking out their nutrients. This problem isn’t a trivial matter since nematodes wreak billions of dollars of damage to the world’s soybean crops each year. So, it’s not surprising that researchers want to understand how exactly these critters attack the plants.

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A nematode, the oblong object on the left, activates the vascular stem cell pathway in the developing nematode feeding site on a plant root. Credit: Xiaoli Guo, University of Missouri

Previous studies by Melissa Goellner Mitchum, a professor at the University of Missouri, had shown that the nematodes release protein fragments, called peptides, near a plant’s roots that help divert the flow of plant nutrients to the worm.

“These parasites damage root systems by creating a unique feeding cell within the roots of their hosts and leeching nutrients out of the soybean plant. This can lead to stunting, wilting and yield loss for the plant,” Mitchum explained in a press release.

In the current PLOS Pathogens study, Mitchum’s team identified another peptide produced by the nematode that is identical to a plant peptide that instructs stem cells to form the plant equivalent of blood vessels. This devious mimicking of the plant peptides is what allows the nematode to trick the plant stem cells into building vessels that reroute the plants’ nutrients directly to the worm.

Mitchum described the big picture implications of this fascinating discovery:

“Understanding how plant-parasitic nematodes modulate host plants to their own benefit is a crucial step in helping to create pest-resistant plants. If we can block those peptides and the pathways nematodes use to overtake the soybean plant, then we can enhance resistance for this very valuable global food source.”

Finding vulnerabilities in treatment-resistant esophageal cancer stem cells

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Illustration of radiation therapy for esophageal cancer.
Credit: Cancer Research UK

The incidence of esophageal cancer has increased more than any other disease over the past 30 years. And while some patients respond well to chemotherapy and radiation treatment, most do not because the cancer becomes resistant to these treatments.

Focusing on cancer stem cells, researchers at Trinity College Dublin have identified an approach that may overcome treatment resistance.

Within tumors are thought to lie cancer stem cells that, just like stem cells, have the ability to multiply indefinitely. Even though they make up a small portion of a tumor, in some patients the cancer stem cells evade the initial rounds of treatment and are responsible for the return of the cancer which is often more aggressive. Currently, there’s no effective way to figure out how well a patient with esophageal cancer will response to treatment.

In the current study published in Oncotarget, the researchers found that a genetic molecule called miR-17 was much less abundant in the esophageal cancer stem cells. In fact, the cancer stem cells with the lowest levels of miR-17, were the most resistant to radiation therapy. The researchers went on to show that adding back miR-17 to the highly resistant cells made them sensitive again to the radiation. Niamh Lynam-Lennon, the study’s first author, explained in a press release that these results could have direct clinical applications:

“Going forward, we could use synthetic miR-17 as an addition to radiotherapy to enhance its effectiveness in patients. This is a real possibility as a number of other synthetic miR-molecules are currently in clinical trials for treating other diseases.”

Curing the Incurable through Definitive Medicine

“Curing the Incurable”. That was the theme for the first annual Center for Definitive and Curative Medicine (CDCM) Symposium held last week at Stanford University, in Palo Alto, California.

The CDCM is a joint initiative amongst Stanford Healthcare, Stanford Children’s Health and the Stanford School of Medicine. Its mission is to foster an environment that accelerates the development and translation of cell and gene therapies into clinical trials.

The research symposium focused on “the exciting first-in-human cell and gene therapies currently under development at Stanford in bone marrow, skin, cardiac, neural, pancreatic and neoplastic diseases.” These talks were organized into four different sessions: cell therapies for neurological disorders, stem cell-derived tissue replacement therapies, genome-edited cell therapies and anti-cancer cell-based therapies.

A few of the symposium speakers are CIRM-funded grantees, and we’ll briefly touch on their talks below.

Targeting cancer

The keynote speaker was Irv Weissman, who talked about hematopoietic or blood-forming stem cells and their value as a cell therapy for patients with blood disorders and cancer. One of the projects he discussed is a molecule called CD47 that is found on the surface of cancer cells. He explained that CD47 appears on all types of cancer cells more abundantly than on normal cells and is a promising therapeutic target for cancer.

Irv Weissman

Irv Weissman

“CD47 is the first gene whose overexpression is common to all cancer. We know it’s molecular mechanism from which we can develop targeted therapies. This would be impossible without collaborations between clinicians and scientists.”

 

At the end of his talk, Weissman acknowledged the importance of CIRM’s funding for advancing an antibody therapeutic targeting CD47 into a clinical trial for solid cancer tumors. He said CIRM’s existence is essential because it “funds [stem cell-based] research through the [financial] valley of death.” He further explained that CIRM is the only funding entity that takes basic stem cell research all the way through the clinical pipeline into a therapy.

Improving bone marrow transplants

judith shizuru

Judith Shizuru

Next, we heard a talk from Judith Shizuru on ways to improve current bone-marrow transplantation techniques. She explained how this form of stem cell transplant is “the most powerful form of cell therapy out there, for cancers or deficiencies in blood formation.” Inducing immune system tolerance, improving organ transplant outcomes in patients, and treating autoimmune diseases are all applications of bone marrow transplants. But this technique also carries with it toxic and potentially deadly side effects, including weakening of the immune system and graft vs host disease.

Shizuru talked about her team’s goal of improving the engraftment, or survival and integration, of bone marrow stem cells after transplantation. They are using an antibody against a molecule called CD117 which sits on the surface of blood stem cells and acts as an elimination signal. By blocking CD117 with an antibody, they improved the engraftment of bone marrow stem cells in mice and also removed the need for chemotherapy treatment, which is used to kill off bone marrow stem cells in the host. Shizuru is now testing her antibody therapy in a CIRM-funded clinical trial in humans and mentioned that this therapy has the potential to treat a wide variety of diseases such as sickle cell anemia, leukemias, and multiple sclerosis.

Tackling stroke and heart disease

img_1327We also heard from two CIRM-funded professors working on cell-based therapies for stroke and heart disease. Gary Steinberg’s team is using human neural progenitor cells, which develop into cells of the brain and spinal cord, to treat patients who’ve suffered from stroke. A stroke cuts off the blood supply to the brain, causing the death of brain cells and consequently the loss of function of different parts of the body.  He showed emotional videos of stroke patients whose function and speech dramatically improved following the stem cell transplant. One of these patients was Sonia Olea, a young woman in her 30’s who lost the ability to use most of her right side following her stroke. You can read about her inspiring recover post stem cell transplant in our Stories of Hope.

Dr. Joe Wu. (Image Source: Sean Culligan/OZY)

Dr. Joe Wu. (Image Source: Sean Culligan/OZY)

Joe Wu followed with a talk on adult stem cell therapies for heart disease. His work, which is funded by a CIRM disease team grant, involves making heart cells called cardiomyocytes from human embryonic stem cells and transplanting these cells into patient with end stage heart failure to improve heart function. His team’s work has advanced to the point where Wu said they are planning to file for an investigational new drug (IND) application with the US Food and Drug Administration (FDA) in six months. This is the crucial next step before a treatment can be tested in clinical trials. Joe ended his talk by making an important statement about expectations on how long it will take before stem cell treatments are available to patients.

He said, “Time changes everything. It [stem cell research] takes time. There is a lot of promise for the future of stem cell therapy.”

Stories that caught our eye: new target for killing leukemia cancer stem cells and stem cell vesicles halt glaucoma

New stem cell target for acute myeloid leukemia (Karen Ring).  A new treatment for acute myeloid leukemia, a type of blood cancer that turns bone marrow stem cells cancerous, could be in the works in the form of a cancer stem cell destroying antibody.

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Acute Myeloid Leukemia (Credit: Medscape)

Scientists from the NYU Langone Medical Center and the Memorial Sloan Kettering Cancer Center identified a protein called CD99 that appears more abundantly on the surface of abnormal blood cancer stem cells compared to healthy blood stem cells. They developed an antibody that specifically recognizes and kills the CD99 wielding cancer stem cells while leaving the healthy blood stem cells unharmed.

The CD99 antibody was effective at killing human AML stem cells in a dish and in mice that were transplanted with the same type of cancer stem cells. Further studies revealed that the CD99 antibody when attached to the surface of cancer stem cells, sets off a cascade of enzyme activity that causes these cells to die. These findings suggest that cancer stem cells express more CD99 as a protective mechanism against cell death.

In an interview with Genetic Engineering and Biotechnology News, Chris Park, senior author on the Science Translational Medicine study, explained the importance of their work:

“Our findings not only identify a new molecule expressed on stem cells that drive these human malignancies, but we also show that antibodies against this target can directly kill human AML stem cells. While we still have important details to work out, CD99 is likely to be an exploitable therapeutic target for most AML and MDS patients, and we are working urgently to finalize a therapy for human testing.”

While this work is still in the early stages, Dr. Park stressed that his team is actively working to translate their CD99 antibody therapy into clinical trials.

“With the appropriate support, we believe we can rapidly determine the best antibodies for use in patients, produce them at the quality needed to verify our results, and apply for permission to begin clinical trials.”

 

Peculiar stem cell function may help treat blindness (Todd Dubnicoff). Scientists at the National Eye Institute (NEI) have uncovered a novel function that stem cells use to carry out their healing powers and it may lead to therapies for glaucoma, the leading cause of blindness in United States. Reporting this week in Stem Cells Translational Medicine, the researchers show that stem cells send out regenerative signals by shedding tiny vesicles called exosomes. Once thought to be merely a garbage disposal system, exosomes are now recognized as an important means of communication between cells. As they bud off from the cells, the exosomes carry proteins and genetic material that can be absorbed by other cells.

Microscopy image shows exosomes (green) surrounding retinal ganglion cells (orange and yellow). Credit: Ben Mead

Microscopy image shows exosomes (green) surrounding retinal ganglion cells (orange and yellow). Credit: Ben Mead

The researchers at NEI isolated exosomes from bone marrow stem cells and injected them into the eyes of rats with glaucoma symptoms. Without treatment, these animals lose about 90 percent of their retinal ganglion cells, the cells responsible for forming the optic nerve and for sending visual information to the brain. With the exosome treatment, the rats only lost a third of the retinal ganglion cells. The team determined that microRNAs – small genetic molecules that can inhibit gene activity – inside the exosome were responsible for the effect.

Exosomes have some big advantages over stem cells when comes to developing and manufacturing therapies which lead author Ben Mead explains in a press release picked up by Eureka Alert:

“Exosomes can be purified, stored and precisely dosed in ways that stem cells cannot.”

We’ll definitely keep our eyes on this development. If these glaucoma studies continue to look promising it stands to reason that there would be exosome applications in many other diseases.

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 and gene therapy research gets a good report card from industry leader

arm

Panel discussion at ARM State of the industry briefing: left to Right Robert Preti, Chair ARM; Jeff Walsh, bluebird bio; Manfred Rudiger, Kiadis Pharma; Barbara Sasu, Pfizer;  Thomas Farrell, Bellicum Pharmaceuticals. Photo courtesy ARM.

The state of the regenerative medicine field is strong and getting stronger. That was the bottom line verdict at the 2017 Cell and Gene Therapies State of the Industry briefing in San Francisco.

The briefing, an annual update on the field presented by the Alliance for Regenerative Medicine (ARM), gave a “by the numbers” look at the field and apart from one negative spot everything is moving in the right direction.

Robert Preti, Chair of ARM’s Board, said worldwide there are more than 750 regenerative companies working in the stem cell and gene therapy space. And those companies are increasingly moving the research out of the lab and into clinical trials in people.

For example, at the end of 2016 there were 802 clinical trials underway. That is a 21 percent growth over 2015. Those breakdown as follows:

Phase 1 – 271 (compared to 192 in 2015)

Phase 2 – 465 (compared to 376 in 2015)

Phase 3 – 66 (compared to 63 in 2015)

The bulk of these clinical trials, 45 percent, are focused on cancer. The second largest target, 11 percent, is on heart disease. The number of trials for neurological disorders and rare diseases are also growing in number.

Preti says the industry is at an important inflection point right now and that this growth is presenting new problems:

“The pipeline of products is robust and the technologies supporting that pipeline is even more robust. The technologies that are fueling the growth in clinical activity have accelerated so fast that we on the manufacturing side are playing catchup. We are at a point where we have to get serious about large scale commercial production.”

Preti also talked about “harmonization” of the regulatory process and the need to have a system that makes it easier for products approved for clinical trials in one country, to get approval for clinical trials in other countries.

Michael Werner, the executive director of ARM, said the organization has played a key role in helping promote the field and cited the recently passed 21st Century Cures Act as “a major win and a powerful statement of ARM’s leadership in this sector.”

But there was one area where the news wasn’t all positive, the ability of companies to raise capital. In 2015 companies raised $11 billion for research. In 2016 it was less than half of that, $5.3 billion.

With that somber note in mind it was appropriate that the panel discussion that followed the briefing was focused on the near-term and long-term challenges facing the field if it was to be commercially successful.

One of the big challenges was the issue of regulatory approval, and here the panel seemed to be more optimistic than in previous years.

Manfred Rüdiger of Kiadis Pharma said he was pleasantly surprised at how easy it was to work with different regulatory agencies in the US, Canada and Europe.

“We used them as a kind of free consultancy service, listening to their advice and making the changes they suggested so that we were able to use the same manufacturing process in Europe and Canada and the US.”

Jeff Walsh of bluebird bio, said the key to having a good working relationship with regulatory agencies like the Food and Drug Administration (FDA) is simple:

“Trust and transparency between you and the regulatory agencies is essential, it’s a critical factor in advancing your work. The agencies respond well when you have that trust. One thing we can’t be is afraid to ask. The agencies will tell you where their line is, but don’t be afraid to ask or to push the boundaries. This is new for everyone, companies and regulators, so if you are pushing it helps create the environment that allows you to work together to develop safe therapies that benefit patients.”

Another big issue was scalability in manufacturing; that it’s one thing to produce enough of a product to carry out a clinical trial but completely different if you are hoping to use that same product to treat millions of people spread out all over the US or the world.

And of course cost is always something that is front and center in people’s minds. How do you develop therapies that are not just safe and effective, but also affordable? How do companies ensure they will get reimbursed by health insurers for the treatments? No one had any simple answer to what are clearly very complex problems. But all recognized the need to start thinking about these now, long before the treatments themselves are even ready.

Walsh ended by saying:

“This is not just about what can you charge but what should you charge. We have a responsibility to engage with the agencies and ultimately the payers that make these decisions, in the same way we engage with regulatory agencies; with a sense of openness, trust and transparency. Too often companies wait too long, too late before turning to the payers and trying to decide what is appropriate to charge.”