The Dark Side of Stem Cells

If you are interested in stem cell research, the biology of cancer cells or promising new targets for anti-cancer therapy, today is your lucky day. Two new studies, one from Italy and one from Canada, both report an astonishing finding: human colon tumors contain cancer stem cells that not only can be identified and separated from ordinary cancer cells, but can successfully transplanted into mice, forming identical tumors that can be serially transplanted for several generations. Here are links to the abstracts; the articles will appear in Nature:

Identification and expansion of human colon-cancer-initiating cells

A human colon cancer cell capable of initiating tumour growth in immunodeficient mice

This news article from The Globe and Mail, announcing the discovery, is both detailed and well written. I encourage those who are interested in stem cell research to read it. Here is an excerpt:

Current therapies treat all cancer cells the same. They're aimed at shrinking tumours on the basis that the various cells within them all have similar powers to spawn new cancers and spread destruction. But mounting evidence suggests that cancer's real culprits -- the roots of perhaps every tumour -- are actually a small subset of bad seeds known best to the world as stem cells.

"It is not unreasonable to say that all this time, the 30 or 40 years that chemotherapy and radiation [have] been around, we've been going after the wrong cells," said Alan Bernstein, president of the Canadian Institutes of Health Research, the country's main medical research funding agency. If the theory bears out, he said, "All of our therapies have been targeting and killing the pawns.

"But like chess, you have to kill the king to win the game."

I predict that within the next five to ten years multiple targeted therapies against the cancer stem cell will be identified, developed, tested and approved for human use. For example, in these reports the CD133 antigen was used to identify colon cancer stem cells, which means that now researchers can see if blocking the activity of this antigen drives the cell toward apoptosis or some other equally horrific (God willing) death.

For those fans of submarine warfare this discovery is equivalent to "pinging" an enemy sub and locating it in the murky deep. Now all we need to do is fire off our torpedoes before the bad guys get away.

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Emmy,
There is only a ban on embryonic stem cell research. Embryonic stem cell research is problematic for some people and groups because it involves the destruction of an embryo. Folks who believe that life begins at conception have a problem with this.

Adult stem cell research, OtOH, involves removing living tissue from adults. Stem cells are removed from this harvested tissue for research.

This is where politics and science (and the media for that matter) don't mix. There's a bunch of press about stem cell this and stem cell that but no mention of the difference between adult and embryonic stem cells. Thus, there are those who believe that all stem cell research is outlawed and those who believe they are against all stem cell research.

First you'd have to say where "this country" is. The research for the first paper was carried out in Italy, seemingly at the Istituto Superiore di Sanità, Rome; the Mediterranean Institute of Oncology, Catania; Sant'Andrea Hospital, Rome; and the University of Palermo in Palermo. The research for the letter was carried out in Canada, seemingly at the University Health Network, Toronto; Mount Sinai Hospital, Toronto; and the University of Toronto in Toronto. And it involves looking for stem cells in cancerous tumours, not encouraging them to form from fertilized eggs at the 8-cell stage.

There is NO ban on stem cell research. It's just that they government does not fund embryonic stem cell reseaarch. Drug companies are free to do whatever stem cell sesearch they want.

I just don't see much cash on the table yet.

A team of researchers at Vanderbilt University just released results on mathematical modeling of tumors. Their findings echo the results described in the Globe and Mail article without "fingering" stem cells by name. They also assert that "environmental hardships" experienced by tumors - such as chemotherapy - can provoke any remaining cancer cells to more aggressive growth and mobility.

http://www.mc.vanderbilt.edu/reporter/index.html?ID=5181

Though their findings may seem to be discouraging, the existence of a good mathematical model for tumor cell metabolism and growth should enable fast and detailed studies of problems which are hard to study clinically - such as the response of various tumor types to different dosage regimes, interactions among multiple chemotherapies, even the connections between dietary interventions and chemotherapy.