last updated April 2013
Targeting cancer at the source
Revelation of a pathway that controls the proliferation of breast cancer stem cells could provide new drug targets
Cell biologists showed recently that a small subset of tumor cells, called cancer stem cells, cause tumor initiation and growth. Targeting these cells is essential to treating cancers effectively. Now, a research team led by Noriko Gotoh at the University of Tokyo, Japan, has revealed a pathway that may be essential to the survival and proliferation of breast cancer stem cells (BCSCs)1, opening the doorway for development of new treatments.
The ability of individual BCSCs to replicate in culture and form multicellular spheres, called mammospheres, reflects their ability to generate tumors. Gotoh and colleagues found that heregulin (HRG), a widely expressed extracellular growth factor, induced mammosphere formation in BCSCs. HRG triggered expression of the transcription factor NF-κB, which regulates inflammatory gene expression. NF-κB enhanced expression of interleukin-8 (IL8), which belongs to a class of molecules that can direct movement of nearby responsive cells, and is known to increase the capacity of BCSCs to proliferate. To confirm that NF-κB plays a key role in the pathway, the researchers injected mice with breast cancer cells expressing an NF-κB inhibitor; the mice did not develop tumors.
Gotoh and colleagues are currently searching for molecules in the pathway that can be used as drug targets or biomarkers in cancer therapy.