Cells expressing CD133 and the chemokine receptor CXCR4 are implicated.
Ludwig-Maximilians-University scientists identified a subpopulation of cancer stem cells (CSCs) that is responsible for metastasis of a type of human pancreatic cancer.
In the study, the investigators discovered that human pancreatic cancer tissue contains tumorigenic and chemotherapy-resistant stem cells defined by expression of CD133, a surface marker expressed by a variety of normal and malignant stem cells. They identified a distinct subset of cells expressing both CD133 and the chemokine receptor CXCR4, which plays a key role in blood cell migration in the invasive front of the tumor.
When the team implanted mice with isolated CD133+/CXCR4+ cells, they developed metastatic tumors. Cancer spread was abolished, however, by inhibiting CXCR4 or by transplanting CD133+/CXCR4- cells instead. The researchers say that this underlines the importance of CXCR4 for the invasive cell behavior.
Further clinical studies revealed that tumor samples with a high number of CXCR4+ cells were more migratory and came from patients that suffered from more advanced metastatic disease.
The study is published in the September issue of Cell Stem Cell.