Using MKK4's metastasis suppressor function to identify and dissect cancer cell-microenvironment interactions during metastatic colonization.

Host tissue microenvironment plays key roles in cancer progression and colonization of secondary organs. One example is ovarian cancer, which colonizes the peritoneal cavity and especially the omentum. Our research indicates that the interaction of ovarian cancer cells with the omental microenvironment can activate a stress-kinase pathway involving the mitogen-activated protein kinase kinase 4 (MKK4). A combination of clinical correlative and functional data suggests that MKK4 activation suppresses growth of ovarian cancer cells lodged in omentum. These findings prompted us to turn our focus to the cellular composition of the omental microenvironment and its role in regulating cancer growth. In this review, in addition to providing an overview of MKK4 function, we highlight a use for metastasis suppressors as a molecular tool to study cancer cell interaction with its microenvironment. We review features of the omentum that makes it a favorable microenvironment for metastatic colonization. In conclusion, a broader, evolutionary biology perspective is presented which we believe needs to be considered when studying the evolution of cancer cells within a defined microenvironment. Taken together, this approach can direct new multi-dimensional lines of research aimed at a mechanistic understanding of host tissue microenvironment, which could be used to realize novel targets for future research.