BoneKEy Reports | BoneKEy Watch
Periostin induced by tumor cells supports distant metastases
DOI:10.1038/bonekey.2012.22
Metastatic colonization is an inefficient process; it can only occur in the presence of stromal niche signals that support the expansion of cancer cells that disseminate to distant sites. In this study, the MMTV-PyMT mouse model of metastatic breast cancer, in which metastatic tumors form spontaneously in the lungs, has been used to identify periostin, a protein encoded by the POSTN gene, as an important mediator of metastatic colonization. In normal development, periostin is incorporated into the extracellular matrix and is important in the development and function of bone, tooth and cardiac tissue.
In order to survive, tumor cells that infiltrate secondary tissue need to induce POSTN expression by fibroblasts in the extracellular matrix. POSTN expression is also necessary to support the growth of the metastatic tumor, and blocking its function also blocks metastasis, suggesting a therapeutic application. This study confirmed the importance of periostin, which appears to work via the Wnt signaling pathway in cancer stem cells, by showing that POSTN-deficient mice cannot support even small metastatic growths.
Editor's comment: Periostin, an extracellular matrix protein induced in the lung stroma by cancer stem cells, provides a niche to support stem cell growth, demonstrating the importance of single extracellular matrix proteins as survival factors during the early phase of metastasis.
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