Msi1 controls cell differentiation and regulates Wnt and Notch pathways.
Researchers at Georgetown University Medical Center discovered that the gene Musashi1 (Msi1) associated with human breast stem cells stimulates mammary cell development by activating two pathways.
Recent studies have implicated Msi1 as a human stem cell marker, since it has been found in human breast, colon, brain, skin, and other cells, according to the scientists. They found that Msi1 drives mammary cells along different lineages; i.e., it can decide what type of cell develops in the breast. The researchers also observed that Msi1 is expressed in particularly aggressive tumors. Furthermore, they showed that Msi1 regulates Wnt and Notch pathways in mammary cells. Both these pathways help control stem-cell growth and are known to be critically important to the development of many cancers.
Studying how Msi1 drives the Wnt and Notch pathways, the investigators also noted that when Msi1 was overexpressed, there was an increased secretion of a growth factor known as proliferin and reduced secretion of the Wnt pathway inhibitor Dickkopf-3. Additionally, Msi1 programmed the expression of a number of genes that have an effect on the cell cycle, they report.
The findings were reported at the annual meeting of the American Association for Cancer Research.
