Disclosed herein are methods to inhibit cleavage of a type I receptor of transforming growth factor beta (TβRI) and reduce cancer cell invasiveness/metastasis, and agents and pharmaceutical compositions for use in these methods. Also disclosed herein are methods for identifying agents that inhibit cleavage of TβRI and methods for diagnosing and/or prognosing cancer based on nuclear localization of a intracellular domain of TβRI, which is a product of TβRI cleavage.