New mission for salinomycin in cancer by Cord Naujokat, SciTopics, July 15, 2010. Excerpt (in the "continue reading" section):

In addition, a very recent study demonstrates that salinomycin overcomes ATP-binding cassette (ABC) transporter-mediated multidrug and apoptosis resistance in human leukemia stem cell-like cells (3).

Reference #3: Salinomycin overcomes ABC transporter-mediated multidrug and apoptosis resistance in human leukemia stem cell-like KG-1a cells, by Dominik Fuchs and 4 co-authors, including Cord Naujokat, Biochem Biophys Res Commun 2010(Apr 16);394(4): 1098-104 [Epub 2010(Mar 27)][PubMed citation].

Comments: Near the end of this article about salinomycin is the comment that "the investigation of its safety, toxicity, pharmacology and anticancer activity in humans will be a challenge." The author then mentions a preliminary study of "a small cohort of patients with metastatic breast cancer or metastatic head and neck cancers". The results of this preliminary study of the toxicity of salinomycin are summarized. They have not yet been published in the peer-reviewed literature, although a manuscript has been submitted [see reference #4 in the article]. The implication of these preliminary results is that there may be a "therapeutic window" for salinomycin, that is, a drug dosage that yields clinically significant benefits in the absence of excessive toxicity.

For a previous commentary on salinomycin, see: Cancer stem cell breakthrough by Kat Arney, Science Update blog, Cancer Research UK, August 14, 2009. Excerpt:

We need to stress that these were laboratory experiments, and there is no evidence yet that salinomycin can treat cancer in humans. Salinomycin is currently used as an antibiotic for chickens and cows, and it can be toxic or even fatal to humans, causing serious muscle and heart problems.

If there is a "therapeutic window" for salinomycin, it could be a small one, and is likely to vary from one tumor to another.

For a previous post to this blog about salinomycin, see: Identification of selective inhibitors of breast CSCs in mice, August 14, 2009.