Stem cell “niche” discovery holds promise for new treatments

01 September 2007

Dr Mick Bhatia September 2007 – Canadian Cancer Society researchers have made an important and unexpected discovery about stem cells that opens the door to new avenues of stem cell research in labs around the world.

In an article published in Nature, Dr Mick Bhatia and his team at the McMaster Cancer and Stem Cell Research Institute in Hamilton show how they discovered that embryonic stem cells build themselves a protective “niche” which, in turn, feeds and nurtures the stem cells with a combination of special protein growth factors. These proteins appear to be able to determine what the stem cells do: whether they replicate (make copies of themselves) or differentiate (turn themselves into completely new kinds of cells, such as blood, bone or neurons).

Dr Bhatia believes that if scientists can target this niche rather than the stem cells, they may be able to control the process of stem cell differentiation rather than just copy themselves.  “Stem cells are like perpetual photocopiers,” says Dr Bhatia. “If we want something different to come out we have to stop the copy function first. Controlling the niche is like controlling the copier itself so the cells can produce mature differentiated cells.”

Researchers around the world are working on ways to coax stem cells to differentiate, with the goal of one day being able supply replacement cells or tissue that can be transplanted to treat diseases for which there are no surgical or drug treatments, such as diabetes, Parkinson’s, spinal chord injuries and Alzheimer’s. But growing and then successfully directing the cells has proven to be very difficult. “Every stem cell has hundreds of choices to make,” says Dr Bhatia. “Now that we have access to the food supply through the niche, we think it will be easier to direct these choices with the right recipes of chemicals and proteins.”

This new discovery also holds great promise for the treatment of cancer. “Based on the pioneering work of John Dick, we now think a lot of human tumours come from mutated stem cells,” says Dr Bhatia. “Chemotherapy normally targets the tumour cells themselves, but perhaps if we target the cancer stem cell niche we can cut off a tumour’s nutrient supply and starve it to death at its source”

With a five-year grant from the Society for further research, he also believes that the niche will provide a way to grow human cells in a dish that can mimic tumour growth and development, something scientists have never been able to observe. “We are very excited about the possibilities for cancer treatment,” he says.