A Stem Cell-Based Therapy for Colon Cancer


Colorectal cancer is the third leading cause of death in the Western World. Like many other types of cancer, colorectal cancer spreads and is propagated by cancer stem cells. Therefore, understanding how to inhibit the growth of cancer stem cells provides a key to treating the cancer itself.

By inactivating a gene that drives stem cell renewal in cancer stem cells, scientists and surgeons at the Princess Margaret Cancer Centre in Toronto, Canada, have discovered a promising new approach to treating colorectal cancer.

John Dick, a senior scientist at the Princess Margaret Cancer Centre, said, “This is the first step toward clinically applying the principles of cancer stem cell biology to control cancer growth and advance the development of durable cures.”

In preclinical experiments with laboratory rodents, Dick and his team identified a gene called BMI-1 as a pivotal regulator of colon cancer stem cell proliferation. With this knowledge in hand, Dick’s laboratory dedicated many hours to finding small molecules that disarm BMI-1. Then Dick and his co-workers replicated human colorectal cancer in mice, and used their BMI-1-inhibiting small molecules to treat these cancer-stricken mice.

According to lead author of this work, Antonija Kreso: “Inhibiting a recognized regulator of self-renewal is an effective approach to control tumor growth, providing strong evidence for the clinical relevance of self-renewal as a biological process for therapeutic targeting.”

Dr. Dick explained: “When we blocked the BMI-1 pathway, the stem cells were unable to self-renew, which resulted in long-term and irreversible impairment of tumor growth. In other words, the cancer was permanently shut down.”

The clinical potential of this approach is significant, since it provides a viable treatment that specifically targets colon cancer. About 65% of all colorectal cancers have an activated BMI-1 pathway. Since physicians now have techniques for identifying the presence of BMI-1 and the tools to inhibit it, this strategy could translate into a clinical treatment that might radically transform the treatment of aggressive, advanced colorectal cancers. Such a treatment would be specific, personal, and specific. May the phase 1 trials begin soon!!!

Umbilical Cord Stem Cells Outperform Bone Marrow Stem Cell in Heart Repair


A study from the laboratory of Armand Keating at the University of Toronto and Princess Margaret Hospital has compared the ability of umbilical cord stem cells and bone marrow stem cells to repair the hearts of laboratory animals after a heart attack. The umbilical cord stem cells showed a clear superiority to bone marrow stem cells when it came to repairing heart muscle.

Keating used human umbilical cord perivascular cells (HUCPVCs) for his experiment, and these cells are widely regarded as a form of umbilical cord mesenchymal stem cell that surround the umbilical cord blood vessels.

Transplantation of cells from either bone marrow or umbilical cord into the heart soon after a heart attack improved the function and structure of the heart. However, functional measurements showed that the HUCPVCs were twice as effective as bone marrow stem cells at repairing the heart muscle.

Keating added: “We are hoping that this translates into fewer people developing complications of heart failure because their muscle function after a heart attack is better.”

In addition to further pre-clinical tests, Keating and his research team hope to initiate clinical trials with human patients within 12-18 months. Keating is also interested in testing the ability of umbilical cord stem cells to heal the hearts of those cancer patients who have experienced heart damage as a result of chemotherapy. In such patients, chemotherapy rids their bodies of cancer, but the cure is worse than the cancer, since the drugs also leave the patients with a severely damaged heart. Such stem cell transplantations could potentially strengthen the hearts of these patients, and give them a new lease on life. My own mother died from congestive heart failure as a result of an experimental arsenic treatment that killed her heart muscle. My mother suffered from chronic myelogenous disease and the arsenic was meant to kill off all the rogue cells in her bone marrow, but instead it killed her heart. If such a stem treatment were available then, my mother might still be with me.

There are over 250 clinical trials with mesenchymal stem cells to date to treat conditions ranging from Crohn’s disease to neurological conditions.  Also, a recent meta-analysis has established the safety of mesenchymal stem cell treatments for several different conditions (see Lalu MM, McIntyre L, Pugliese C, Fergusson D, Winston BW, et al. (2012) Safety of Cell Therapy with Mesenchymal Stromal Cells (SafeCell): A Systematic Review and Meta-Analysis of Clinical Trials. PLoS ONE 7(10): e47559. doi:10.1371/journal.pone.0047559).