A new approach to a deadly childhood cancer

Cancers of the blood, bone marrow and lymph nodes (also called hematologic malignancies) are the most common form of cancer in children and young adults. Current treatments can be effective but can also pose life-threatening health risks to the child. Now researchers at Stanford have developed a new approach and the Board of the California Institute for Regenerative Medicine (CIRM) voted to support that approach in a clinical trial.

The Board approved investing $11,996,634 in the study, which is the Stem Cell Agency’s 76th clinical trial.

The current standard of care for cancers such as acute leukemias and lymphomas is chemotherapy and a bone marrow (also called HCST) transplant. However, without a perfectly matched donor the risk of the patient’s body rejecting the transplant is higher. Patients may also be at greater risk of graft vs host disease (GVHD), where the donor cells attack the patient’s body. In severe cases GVHD can be life-threatening.

Dr. Maria Grazia Roncarlo: Photo courtesy Stanford

Dr. Maria Grazia Roncarolo and her team at Stanford will test an immunotherapy cell approach using a therapy that is enriched with specialized immune cells called type 1 regulatory T (Tr1) cells. These cells will be infused into the patient following the bone marrow transplant. Both the Tr1 cells and the bone marrow will come from the same donor. The hope is this will help rebuild the patient’s immune system, reduce infections and decrease the likelihood of a relapse.

“Every year around 500 children receive stem cell transplants in California, and while many children do well, too many experiences a rejection of the transplant or a relapse of the cancer,” says Dr. Maria T. Millan, President and CEO of CIRM. “Finding an improved therapy for these children means a shorter stay in the hospital, less risk of the need for a second transplant, and a greater quality of life for the child and the whole family.”

The CIRM Board has previously approved funding for 12 other clinical trials targeting cancers of the blood. You can read about them here.

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.