Drug found that kills breast cancer stem cells

This was a matter of time. I work with this people everyday and despite the fact I agree progress is too slow advances are being made.

www.nature.com...

A screen for cancer killers:

A new approach for identifying drugs that specifically attack cancer stem cells, the cellular culprits that are thought to start and maintain tumour growth, could change the way that drug companies and scientists search for therapies in the war against cancer.

"We now have a systematic method that had not been previously known that allows us to find agents that target cancer stem cells," says Piyush Gupta of the Massachusetts Institute of Technology and the Broad Institute in Cambridge, Massachusetts, and first author of the study, published online today in Cell1.

Applying the technique, Gupta and his colleagues discovered one of the first compounds that can selectively destroy cancer stem cells. The drug, an antibiotic commonly fed to pigs and chickens, reduces the proportion of breast cancer stem cells by more than 100-fold compared with a drug widely used in chemotherapy for breast cancer.

Although most cancer therapies wipe out the vast majority of tumour cells, they have not been able to eliminate the cause of the disease — the cancer stem cells — so the cancer often comes roaring back with a vengeance. Researchers have looked for drugs that preferentially target cancer stem cells, but these repeat-offender cells are so rare that screening for potential compounds has been nearly impossible. The study team, led by Robert Weinberg and Eric Lander, also from the Massachusetts Institute of Technology, exploited a trick, boosting the number of cancer-stem-cell-like cells to find a molecular missile that homes in on the real target.

By silencing a specific gene in breast cancer cells, the researchers coaxed them to convert from epithelial cells, which make up most of the human body, into mesenchymal cells, which have many stem-cell-like characteristics. They then used these cells — which have the same molecular signatures as cancer stem cells and are equally drug resistant — to screen around 16,000 chemicals. They found 32 contenders, then whittled the list down to one drug: salinomycin, an antibiotic often found in animal feed.

Drug battle

With a candidate compound in hand, the researchers tested it against the target: stem cells in breast cancer cell lines. In comparisons between salinomycin and paclitaxel, a drug used to treat women with advanced breast cancer, salinomycin repeatedly reduced the proportion of cancer stem cells whereas paclitaxel, also known as Taxol, had the opposite effect. "It's definitely a step forwards," says cancer biologist John Dick of the University of Toronto in Canada, who was not involved in the research.

It's not yet exactly clear how salinomycin eradicates cancer stem cells or whether the compound will find its way into the clinic, says Gupta. His team is using the drug to disrupt various stages of tumour formation and conducting larger scale chemical screens to uncover other cancer-stem-cell-specific candidates.

Michael Lewis, a breast cancer researcher at Baylor College of Medicine in Houston, Texas, says that the paper will force drug companies to reconsider how they screen for agents that block tumour-initiating capacity. "If I was a big pharma company and I had 30,000 compounds on the shelf, I'd screen them all" with this technique, he says. The study's only limitation, he notes, is that the researchers measured the effect of their drug on cancer cell lines rather than on material taken from actual tumours.

The article where this discovery was published has just become available. I'll try to get it as soon as possible.

OK, I just got it.

I'm not going to put the full article here but if someone want's it just send me a message.

From Cell, 13 August 2009

doi:10.1016/j.cell.2009.06.034

Identification of Selective Inhibitors of Cancer Stem Cells by High-Throughput Screening

Screens for agents that specifically kill epithelial cancer stem cells (CSCs) have not been possible due to the rarity of these cells within tumor cell populations and their relative instability in culture. We describe here an approach to screening for agents with epithelial CSC-specific toxicity. We implemented this method in a chemical screen and discovered compounds showing selective toxicity for breast CSCs. One compound, salinomycin, reduces the proportion of CSCs by >100-fold relative to paclitaxel, a commonly used breast cancer chemotherapeutic drug. Treatment of mice with salinomycin inhibits mammary tumor growth invivo and induces increased epithelial differentiation of tumor cells. In addition, global gene expression analyses show that salinomycin treatment results in the loss of expression of breast CSC genes previously identified by analyses of breast tissues isolated directly from patients. This study demonstrates the ability to identify agents with specific toxicity for epithelial CSCs.

There are quite a few controversial facts but I'll be glad to discuss it here if necessary.

I didn't read it carefully but it seems that despite the fact Salinomycin does destroy the cancer cells, I'm still not convinced that that compound targets cancer stem cells.

First they'll have to prove cancer stem cells exist.

I'll talk to the specialists next week.

Hi.

Originally posted by novrod
...they'll have to prove cancer stem cells exist.

That would be a very BAD news, because it is a more "natural"
way for the cancer-stems to show/appear in our body.

For the moment, I "think" that cancer is here, mostly because:
of our way of life,
of our way of eating,
the poisons everywhere,
the exhausts of shops,
all the chemicals in our food. . .
. . .you know what I mean. . . B-)

Soooooo, it will/is very hard to cure the cause(s) !

We have to find other "tricks". . .
. . .or have them stoped being hidden by the greedy we-know-who(s) !

Blue skies.

Canser can be treated without any drug use. Check out this video on utube.

When you take a drug to kill canser cells in your body, you automaticly killing something else with the canser cells. (Curing one thing and killing another) Unfortunately our western medicine is always treating the simptom and not the cause.

Sience of compassion and unconditional love can create miracles. I personally fascinated by the work of Cregg Braden "Spontaneous Healing of Belief"
Check this videos out as well. Very good stuff.

www.youtube.com...

There is a lot of confusion due to years of misinformation.

- cancer happens because of DNA damage or DNA deregulation
- cancer happens due to external factors
- the list can go on but it's just with factors that may contribute to it.

Why 100 year old smokers don't have lung cancer?
Why 1 year old babies have brain tumors?


Now, cancer stem cells may exist, we just don't have any proof they do.

The reason we cannot prevent cancer it's because we still don't understand it.

Yes, there are some cancer types due to bacteria or virus

If we would be able to find cancer stem cells it would be like finding the holly grail. Even though that wouldn't solve the problem completely, although it could save thousands of lifes.

Many colleagues of mine are working hard to find the solution using different approaches.

For instance:
- to starve tumors by shutting down the blood supply
- finding genetic markers to detect cancer cells before they form a tumor
- mapping the genome to find gene hot spots that might work as cancer switches...

And the list keeps going.

I would like a specialist would join this discussion. The best I can do is to pass you my knowledge as a different field scientist or to transmit cancer research research scientists opinions about the new findings.