Pancreatic Cancer Stem Cells

Wuhan, China -

The concept of cancer stem cells has been around for a while. One could say that initially the concept of cancer stem cells was discovered in the hematopoietic system where the group of Dr Dick from Toronto was able to induce human leukemias in mice with injection of as little as 5-10 cells per mouse. Under normal circumstances if one takes leukemic blasts from patients and tries to induce leukemia in the immune deficient mouse, it takes thousands, if not hundreds of thousands of cells to be able to induce leukemia. Dr Dick's group, interestingly enough, also identified the colon cancer stem cell in late 2006. There are patents covering the isolation and use of cancer stem cells for drug development, as well, activities in this area usually are very lucrative, as represented by the 1.5 Billion dollar deal between GSK and the cancer stem cell company Oncomed

In a recent paper (Zhou et al. Persistence of side population cells with high drug efflux capacity in pancreatic cancer. World J Gastroenterol. 2008 Feb 14;14(6):925-30) the widely used human pancreatic cancer cell line, PANC-1 was assessed for stem cell content within the cell line population. Investigators used 2 techniques for identifying stem cell content. The first one involved assessing for a side population cells, and the other one examines expression of drug efflux proteins.

The investigators demonstrated that the cell line PANC-1 expresses a population of side positive cells that comprises about 2.1-8.7 percent of the overall PANCR-1 cell population. Interestingly when the PANC-1 cells were treated with the chemotherapeutic agent Gemcitabine, the number of side positive cells approximately tripled, which was associated with increased expression of the drug efflux transporters ABCB1 and ABCG2.

These data suggest that even in cell line populations one may be able to isolate "cancer stem cells".