Fra1 is required for TGFβ1 induced collective invasion

Abstract

Phenotypic heterogeneity promotes tumor evolution and confounds treatment. Minority subpopulations of trailblazer cells enhance the heterogeneity of invading populations by creating paths in extracellular matrix (ECM) that permit the invasion of phenotypically diverse siblings. The regulatory programs that induce a trailblazer state are poorly understood. Here, we define a new Tgf{beta} induced trailblazer population that is more aggressive than previously characterized Keratin 14 expressing trailblazer cells. Rather than triggering a binary switch to a single trailblazer state, Tgf{beta} induced multiple unique states that were distinguished by their expression of regulatory transcription factors, genes involved in ECM reorganization and capacity to initiate collective invasion. The integration of a parallel Egfr signaling program was necessary to induce pro-motility genes and could be targeted with clinically approved drugs to prevent trailblazer invasion. Surprisingly, Egfr pathway activity also had the collateral consequence of antagonizing the expression of a cohort of Tgf{beta} induced genes, including a subset involved in ECM remodeling. Together, our results reveal a new compromise mode of signal integration that promotes a trailblazer state and can be therapeutically targeted to prevent collective invasion.