Here’s some good news on the cancer front: Toronto researchers think they may be zeroing in on a treatment for colorectal cancer. It all has to do with disarming the gene responsible for allowing colorectal cancer cells to grow and spread. It is this self-renewal system that allows colorectal cancer to take hold, resist treatment, and relapse even after a dose of cancer-killing chemotherapy.
Colorectal cancer is third on the list of cancer-killing diseases in North America.
For their study, the Toronto researchers (based at the Princess Margaret Cancer Centre) decided to zero-in on cancer stem cells. To better understand the results of the study, let’s explore what stem cells are.
Stem cells are different from other cells in two very specific ways: they can renew themselves through cell division, even after long periods of being inactive; and they can change into specific cells designed to perform special functions. So stem cells have an amazing ability to develop into many different cell types. They can also function as a repair system, replenishing cells that become damaged or that die. Every time a stem cell divides, it has the potential to become another stem cell, or a specialized cell such as a muscle cell, red blood cell, or brain cell.
Unfortunately, cancer stem cells also possess some of these amazing characteristics. They can morph into any type of cell associated with a particular cancer. This ability means that they are tumorigenic, or tumor-forming. Like normal stem cells, cancer stem cells are capable of self-renewal and differentiation into other cell types. These are the cells that cause tumors to relapse and grow into new tumors.
By disarming the gene that allows cancer stem cells to self-renew and differentiate, the researchers think they should be able to control cancer growth. They also think that a treatment for colorectal cancer may be in the foreseeable future if they can learn to control colorectal cancer stem cells.
The research team had previously identified leukemia stem cells and colon cancer stem cells. It was this preliminary research that led the way for the more in-depth findings about colorectal cancer stem cells. The researchers say that inhibiting the pathways that lead to the self-renewal of cancer stem cells is likely the future of cancer treatment. It is this biological process that needs to be targeted by future studies aimed at finding a cure for cancer.
In this particular study, the research team blocked a pathway called BMI-1. Once the pathway was blocked, the cancer stem cells were unable to self-renew. This resulted in long term and irreversible interference with tumor growth. Eventually, the ability to grow tumors was completely and entirely shut-down. And that, the researchers say, means no more cancer.
Clearly, this is an exciting discovery. There is great clinical potential in isolating and shutting down the pathways that allow cancer stem cells to self-renew. The only question that remains is how long it will take scientists to translate this knowledge into personalized cancer medicine.
Zlomislic, D., “People to Watch: Stem-cell researcher aims to kill root of cancer recurrence,” The Toronto Star web site, Dec. 29, 2014; http://www.thestar.com/news/insight/2013/12/29/people_to_watch_stemcell_researcher_aims_to_kill_root_of_cancer_recurrence.html, last accessed Jan. 7, 2014.
“Cancer: New Discovery for Tumour Growth,” University Health Network web site, Dec. 17, 2012; http://www.uhnres.utoronto.ca/news/php/readarticle.php?id=42327, last accessed Jan. 7, 2014.