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3 posts from October 2009

October 28, 2009

New Canadian-Californian investment in stem cell research aims to improve cancer treatments

I am excited to learn of today’s announcement that two large-scale projects to tackle stem cell therapies for cancer are to be funded by the California Institute for Regenerative Medicine (CIRM) and the Cancer Stem Cell Consortium (CSCC). This is most welcome news, not only because it demonstrates a continued investment in stem cell science but because both projects have a critical Canadian component – both projects will be co-led by Canadian investigators.

Half of adults diagnosed with leukemia succumb to the disease. The first project will address the need for novel treatments for leukemia, by developing agents to directly target leukemic stem cells that are resistant to current therapies. This project will be led by Dr. John Dick, Princess Margaret Hospital and Dr. Dennis Carson, University of California San Diego.

The second project will target solid tumor cancers by developing small molecule therapeutics that attack the cancer-initiating cells within the tumors. This project is led by Dr. Tak Mak, Princess Margaret Hospital and Dr. Dennis Slamon, University of California, Los Angeles.

An interesting note is that both Canadian investigators named in the projects are affiliated with the Princess Margaret Hospital in Toronto – the same hospital in which stem cells were discovered by Drs. James Till and Ernest McCulloch nearly 50 years ago. Both Canadian leaders are internationally recognized for their contributions to the stem cell field and they remain at the forefront of cancer stem cell research. Dr. Dick first identified cancer stem cells in 1994 and Dr. Mak’s contributions to immunology have led to significant breakthroughs in understanding cancer biology.

These projects are two of 14 projects that were selected through peer-review by an international committee and will be funded as part of CIRM’s Disease Team Competition, of which the CSCC is a collaborative funding partner. Each project may receive up to $40 million (USD) over four years, with funding for the Canadian investigators contributed by Genome Canada and Canadian Institutes of Health Research through the CSCC and funding for the Californian investigators contributed by CIRM.

Read more:
CIRM media release
CSCC media release

October 14, 2009

Overcoming barriers to successful heart cell transplants

During a heart attack, muscle cells that make up the heart’s tissue are lost permanently. This cell loss is one of the leading causes of heart failure. Although cell transplantation can result in modest improvements in cardiac function, several challenges remain, including how to increase the survival, integration and functionality of the transplanted cells within the host tissue.

New research published this week in the Proceedings of the National Academy of Sciences may provide strategies to overcome these challenges. Stem Cell Network investigator Dr. Peter Zandstra, in collaboration with Dr. Milica Radisic, and their labs at the University of Toronto have developed and tested a method that allows rapid screening of different cell types for their capacity to functionally integrate into heart tissue, and provides insights into the barriers that until now have prevented transplanted cells from adequately merging with the patient’s damaged heart tissue.

The research used an in vitro cell injection test-bed comprised of engineered heart tissue as a basis for their study. Three specific outcomes are reported by lead author Dr. Hannah Song:

  1. The model tissue/cell injection system can functionally distinguish between the cardiac tissue integration capabilities of different injected cell types; 
  2. The model tissue/cell injection system can be used to identify conditions wherein the survival and integration capacities of a specific cell population can be improved; and
  3. Pluripotent stem cell-derived cardiac progenitors can integrate and differentiate in model cardiac tissue, and these cells appear able to significantly improve engineered cardiac tissue function.

Of particular value to scientists is this method’s ability to significantly reduce the time and effort needed to screen known or new cell populations and drugs for their cardiac cell therapy potential, as well as new knowledge about barriers that should be considered during in vivo cardiac cell transplantation studies. In addition, the study suggests, for the first time, that pluripotent stem cell-derived cardiac progenitor cells may be effectively delivered for cardiac cell therapy.

The research was funded in part by the Heart and Stroke Foundation of Ontario.

October 08, 2009

Nobel nominees were the founders of stem cell science

Speculation abounded earlier this week that the founders of stem cell science – James Till and Ernest McCulloch – would be honoured for their achievement with a prestigious Nobel Prize.

While it turned out that the Prize was awarded to a deserving trio of researchers for their work on chromosomes, the buzz of anticipation and conjecture over just who would win has once again thrown two very laudable Canadians into the spotlight.

Till and McCulloch proved the existence of stem cells nearly 50 years ago with their groundbreaking work that studied the effects of radiation on the body’s ability to form blood. In testing irradiated mice that were injected with bone marrow cells, Till and McCulloch discovered bumps on the surface of the spleen in numbers that were directly proportional to the number of injected cells (Radiation Research 1961).  Though they were not the first to have seen such nodules, they were the first to postulate that these nodules were the result of stem cells.

Till and McCulloch subsequently performed very elegant tests to prove the existence of stem cells. First, they created bone marrow cells, each with a unique genetic identifier (or marker) in order to show that each spleen bump was in fact a colony of cells derived from a single cell (Nature 1963). The second test demonstrated that cells within the spleen colony were capable of forming another colony – in other words, the cells were capable of self-renewal. It was the beginning of stem cell science.

Watch the video of Jim Till talking about stem cell science: