Of all the types of stem cells, there is a kind than can be a lot more scary than beautiful: the cancer stem cell. Although the concept of cancer stem cell is still controversial among the scientific community, it is of great medical interest to further understand these cells so that we develop better strategies to tackle them. Cancer stem cells are described as cells with regular stem cell characteristics, they can – self renew (make identical copies of themselves) and – differentiate (give rise to multiple cell types). However, contrary to normal stem cells, they can also give rise to malignant tumors.
Since normal stem cells and cancer stem cells share many characteristics, it is a major challenge to identify molecules (also called markers) that are specifically located on malignant cells and not healthy ones, or mechanisms that are important for the function of malignant cells but not for the function of healthy ones.
In a recent study published in Cell Reports, Lathia and colleagues showed that the junctional adhesion molecule JAM-A was essential for the survival and growth of the cancer stem cells found in glioblastoma, a type of brain tumor; but dispensable for normal brain stem cell function.
In this image, you can observe cancer stem cells obtained from a patient’s glioblastoma and grown in-vitro. In green is JAM-A protein, in red is α-6 integrin protein, and in blue are cell nuclei. Overlap of the green and red (yellow) shows that cells that express α-6 integrin also express JAM-A. Since α-6 integrin was shown to be a marker for glioblastoma cancer stem cells in a previous study by the same group, this picture confirms that JAM-A, being located on the same cells as α-6 integrin, can also be used as a marker for glioblastoma cancer stem cell.
Further down in the study, Lathia and colleagues show that JAM-A is almost undetectable on healthy brain stem cells. Also, blocking of JAM-A reduces cancer stem cell growth but does not affect the growth and function of other healthy brain stem cells. Altogether, since JAM-A is specifically important to glioblastoma cancer stem cell function, it could a promising therapeutic target for treating this type of cancer, making those stem cells a little less scary.
Lathia, J. D., Li, M., Sinyuk, M., Alvarado, A. G., Flavahan, W. A., Stoltz, K., Rosager, A. M., Hale, J., Hitomi, M., Gallagher, J. et al. (2014) ‘High-throughput flow cytometry screening reveals a role for junctional adhesion molecule a as a cancer stem cell maintenance factor’, Cell Rep 6(1): 117-29.