Healthy stem cells could cause harmful tumors in the jaw
LOS ANGELES, USA: Although it is known that abnormal stem cell function contributes to the development of many malignant tumors, the role of stem cells in the formation of benign tumors is not yet fully understood by scientists. Now, new research from the U.S. has demonstrated that stem cells can cause the aggressive growth of ossifying fibroma, a type of rare benign tumor, and subsequent progressive enlargement of the jaw.
In the study, researchers at the University of Southern California's Ostrow School of Dentistry discovered a cellular signaling pathway that converts healthy mesenchymal stem cells, which are multipotent cells that can differentiate into a variety of cell types, in the jaw into ossifying fibroma mesenchymal stem cells.
According to the scientists, the tumor stem cells display increased signaling activity with transforming growth factor beta (TGF-β), a signaling protein that has been associated with other craniofacial malformations. They concluded that upregulation, specifically stimulating inactive genes, of the TGF-β signaling loop appears to increase formation of ossifying fibromas, while suppressing TGF-β signaling seems reduce the tumor's proliferation.
Conventionally, benign tumors such as ossifying fibromas are frequently removed via a surgical procedure. Therefore, the researchers hope that the findings of the current study will contribute to a better understanding of how to stop harmful tumors by inducing ossifying fibroma mesenchymal stem cells to turn into normal mesenchymal stem cells before risky surgery is required.
The study, titled "Ossifying Fibroma Tumor Stem Cells Are Maintained by Epigenetic Regulation of a TSP1/TGF-β/SMAD3 Autocrine Loop," was published in the November issue of the Cell Stem Cell journal.