Our model recapitulates many of the salient physical and biological features of the metastatic microenvironment and should permit investigation of factors that regulate metastatic adhesion, transmigration, and invasion. Open in a separate window THZ531 Figure 2. An microfluidic model of metastatic extravasation and invasion.a) Device design. extravasation and invasion in this model system. These results implicate pericellular HA-rich carcinoma cell associated pericellular matrices in colonization of ectopic sites by circulating tumor cells and support specific targeting of this matrix to limit metastasis in patients. Introduction Changes in the microenvironment at the primary tumor site are key in supporting tumor growth, THZ531 tumor cell survival, and expansion into surrounding tissues. Changes in both the tumor microenvironment and in tumor cell THZ531 programming sanction highly metastatic cells to become anchorage independent and escape the primary tumor microenvironment, a critical step in tumor progression and metastasis. Many primary cancers are associated with an increase in hyaluronan (HA) metabolism which functions in a paracrine fashion to enhance carcinoma growth, survival, and invasiveness1-8. As carcinoma cells acquire the capacity to metastasize they develop an autonomous phenotype which can include synthesis and assembly of a pericellular HA-rich matrix. At the cellular level, these HA-rich pericellular matrices function to organize receptors within plasma membrane microdomains, lowering Rabbit polyclonal to Autoimmune regulator the threshold for activating associated oncogenic signaling pathways, promote cytoskeletal reorganization and impact on an oncogenic transcriptome2. The phenotypic changes associated with these matrices include enhanced therapeutic resistance, increased growth and enhanced motility and invasion. It has been hypothesized that HA-rich tumor cell pericellular matrices function to prevent anoikis, enhance carcinoma cell adhesion to endothelial cells, promote autocrine growth factor sequestration and aid invasion via enhanced HA-receptor signaling cascades3, 7. HA rich pericellular matrices enhance carcinoma cell adhesion to endothelial cellsand transmigration across the endothelium. The tumor cell pericellular matrix may serve as a scaffold for extracellular matrix (ECM) formation in metastatic sites2, 9. Thus, the HA-rich pericellular matrix has potentially critical functions in metastasis and provides a plausible target for better clinical management of cancer patients. A major barrier to testing this hypothesis and to studying many factors that influence the later stages of metastasis, including extravasation and invasion of the metastatic site, is the lack of appropriate model systems. Traditional assays lack key components of the tissue microenvironment such as tissue composition, architecture, and physiologically relevant forces, so may not accurately assess tumor cell ability to metastasize. By contrast, mouse models capture many of the salient features of the tissue microenvironment and have been extremely important in confirming findings from assays; however, they lack the tunability of engineered systems which limits our ability to systematically explore relevant, metastasis-regulating factors. Furthermore, studying the later stages of metastasis models while maintaining the ability to perform high spatiotemporal resolution imaging of pathologic processes including cancer metastasis10-13. Here, we report the development of an model of metastatic extravasation that recapitulates critical aspects of the ectopic site, including a perfusion channel with physiologic flow, a functional endothelium, and a three-dimensional (3D) tissue compartment. Using this platform, we can quantify tumor cell-endothelial adhesion, endothelial transmigration, and tissue invasion. Since this platform permits systematic testing and measurement of key variables, it should enable discovery of pathways and microenvironmental factors that regulate metastasis formation model of metastasis to systematically investigate how pericellular HA matrices surrounding disseminated tumor cells may impact key stages of metastasis formation metastasis model. We also show that pharmacological inhibition of HA synthesis results in reduced pericellular matrix formation.