De-stressing stem cells and the Bonnie & Clyde of stem cells

Dr. John Cashman

The cells in our body are constantly signalling with each other, it’s a critical process by which cells communicate not just with other cells but also with elements within themselves. One of the most important signalling pathways is called Wnt. This plays a key role in early embryonic and later development. But when Wnt signalling goes wrong, it can also help spur the growth of cancer.

Researchers at the Human BioMolecular Research Institute (HBRI) and Stanford University, have reported on a compound that can trigger a cascade of events that create stress and ultimately impact Wnt’s ability to control the ability of cells to repair themselves.

In a news release Dr. Mark Mercola, a co-author of a CIRM-funded study – published in the journal Cell Chemical Biology – says this is important: “because it explains why stressed cells cannot regenerate and heal tissue damage. By blocking the ability to respond to Wnt signaling, cellular stress prevents cells from migrating, replicating and differentiating.”

The researchers discovered a compound PAWI-2 that shows promise in blocking the compound that causes this cascade of problems. Co-author Dr. John Cashman says PAWI-2 could lead to treatments in a wide variety of cancers such as pancreatic, breast, prostate and colon cancer.

“As anti-cancer PAWI-2 drug development progresses, we expect PAWI-2 to be less toxic than current therapeutics for pancreatic cancer, and patients will benefit from improved safety, less side effects and possibly with significant cost-savings.”

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

Speaking of cancer….

Stem cells have many admirable qualities. However, one of their less admirable ones is their ability to occasionally turn into cancer stem cells. Like regular stem cells these have the ability to renew and replicate themselves over time, but as cancer stem cells they use that ability to help fuel the growth and spread of cancer in the body. Now, researchers at U.C. San Diego are trying to better understand how those regular stem cells become cancer stem cells, so they can stop that process.

In a CIRM-funded study Dr. Catriona Jamieson and her team identified two molecules, APOBEC3C and ADAR1, that play a key role in this process.

In a news release Jamieson said: “APOBEC3C and ADAR1 are like the Bonnie and Clyde of pre-cancer stem cells — they drive the cells into malignancy.”

So they studied blood samples from 54 patients with leukemia and 24 without. They found that in response to inflammation, APOBEC3C promotes the rapid production of pre-leukemia stem cells. That in turn enables ADAR1 to go to work, interfering with gene expression in a way that helps those pre-leukemia stem cells turn into leukemia stem cells.

They also found when they blocked the action of ADAR1 or silenced the gene in patient cells in the laboratory, they were able to stop the formation of leukemia stem cells.

The study is published in the journal Cell Reports.

First patient treated for colon cancer using reprogrammed adult cells

Dr. Sandip Patel (left) and Dr. Dan Kaufman (center) of UC San Diego School of Medicine enjoy a light-hearted moment before Derek Ruff (right) receives the first treatment for cancer using human-induced pluripotent stem cells (hiPSCs). Photo courtesy of UC San Diego Health.

For patients battling cancer for the first time, it can be quite a draining and grueling process. Many treatments are successful and patients go into remission. However, there are instances where the cancer returns in a much more aggressive form. Unfortunately, this was the case for Derek Ruff.

After being in remission for ten years, Derek’s cancer returned as Stage IV colon cancer, meaning that the cancer has spread from the colon to distant organs and tissues. According to statistics from Fight Colorectal Cancer, colorectal cancer is the 2nd leading cause of cancer death among men and women combined in the United States. 1 in 20 people will be diagnosed with colorectal cancer in their lifetime and it is estimated that there will be 140,250 new cases in 2019 alone. Fortunately, Derek was able to enroll in a groundbreaking clinical trial to combat his cancer.

In February 2019, as part of a clinical trial at the Moores Cancer Center at UC San Diego Health in collaboration with Fate Therapeutics, Derek became the first patient in the world to be treated for cancer with human-induced pluripotent stem cells (hiPSCs). hiPSCs are human adult cells, such as those found on the skin, that are reprogrammed into stem cells with the ability to turn into virtually any kind of cell. In this trial, hiPSCs were reprogrammed into natural killer (NK) cells, which are specialized immune cells that are very effective at killing cancer cells, and are aimed at treating Derek’s colon cancer.

A video clip from ABC 10 News San Diego features an interview with Derek and the groundbreaking work being done.

In a public release, Dr. Dan Kaufman, one of the lead investigators of this trial at UC San Diego School of Medicine, was quoted as saying,

“This is a landmark accomplishment for the field of stem cell-based medicine and cancer immunotherapy. This clinical trial represents the first use of cells produced from human induced pluripotent stem cells to better treat and fight cancer.”

In the past, CIRM has given Dr. Kaufman funding related to the development of NK cells. One was a $1.9 million grant for developing a different type of NK cell from hiPSCs, which could also potentially treat patients with lethal cancers. The second grant was a $4.7 million grant for developing NK cells from human embryonic stem cells (hESCs) to potentially treat patients with acute myelogenous leukemia (AML).

In the public release, Dr. Kaufman is also quoted as saying,

“This is a culmination of 15 years of work. My lab was the first to produce natural killer cells from human pluripotent stem cells. Together with Fate Therapeutics, we’ve been able to show in preclinical research that this new strategy to produce pluripotent stem cell-derived natural killer cells can effectively kill cancer cells in cell culture and in mouse models.”

Partnering with Big Pharma to benefit patients

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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