Looking into the future, I have no doubt that we will use colon cancer stem cells to find more effective therapies for colon cancer patients and develop novel chemoprevention strategies.
I am collaborating with a basic scientist, Michael Kahn, from the USC Stem Cell Institute. He moved from the Fred Hutchinson Cancer Center to USC to develop novel strategies for cancer stem cells. As many of you know, California will spend over $3 billion over the next 10 years on stem cell research. I have no doubt in my mind that California will be the world leader in a couple of of years in stem cell research and the development of new therapies for a lot of different disorders including cancer.
Recently it has been shown that is possible to isolate cancer stem cells from patients with colon cancer. A group in Toronto (O’Brien) and in Italy (Ricci) were able to isolate tumor cells from colon cancer patients which were able to initiate growth in vitro and in vivo.
Over the last 6 months we have started to isolate CD133+ cells from our patients undergoing surgery for their primary tumor and liver metastases. Of course we ask for permission, and patients sign an informed consent. We have been successful isolating these colon cancer stem cells and growing them in the laboratory.
The most important fact is that Dr. Kahn has developed a very promising drug to treat these colon cancer stem cells effectively. We are so excited to be able to work with him and develop this drug for our patients. Both laboratories (Dr. Kahn’s and mine) are working around the clock to advance the understanding how colon cancer stem cells work and how important they are in the clinic.
To simplify their role in the treatment of colon cancer, imagine a tree with leaves. In many cases with chemotherapy we can remove the leaves from the tree but not take out the tree’s trunk, and the tree will grow back. We have a similar situation in patients with colon cancer. We often can shrink the tumor, but in many cases the tumor grows back, mainly because of the stem cells which are very resistant to chemotherapy.
We need a completely different treatment approach to eradicate them. One of these approaches is ICG-001 which Dr. Kahn developed. So far we have not seen any toxicity but have seen interesting effects on CD133+ cells and development of metastases.
It is critical in the future to understand these colon cancer stem cells to be able to identify better therapeutic strategies for patients with colon cancer. USC is on the forefront of this research and we are very excited about the recent progress of our research in colon cancer stem cells.