A Truncated Form of the Polarity Protein SCRIB Induces Apoptosis in MDA-MB231 Cells by Regulating Components of Several Signalling Pathways

Polarity proteins are fundamental to the establishment and maintenance of breast tissue integrity, whereas alterations of their amino acid sequence and protein structure can drive breast cancer formation and progression. Scrib is a multi-functional scaffold protein whose proper localization within the cell is pivotal for its correct function. We report here that the ectopic expression of a truncated form of the polarity protein of the LRR domain, drives MDA-MB231 breast cancer cells to caspase 3-mediated apoptotic cell death. Furthermore, we identify the truncated Scrib as a regulator of JNK/c-Jun, Notch and Wnt/β-catenin signalling pathways. Our results indicate that the ectopic expression of the truncated Scrib in a breast cancer cell line with a specific background of genetic mutations (KRAS, AFRGAP1, BRAF, MYCL) activates a program of intracellular molecular alterations and promotes apoptosis.