Epithelial to mesenchymal transition (EMT) confers migratory and dynamic properties on cells and, as such, plays a pivotal role in the development of metastatic, castration resistant prostate cancer. The amyloid precursor protein (APP), although most closely associated with the neurodegenerative condition Alzheimer's disease, has also been linked to the pathogenesis and prognosis of several cancers including prostate cancer. Aims: To investigate whether over-expression of APP could promote EMT in prostate cancer (PCa) DU145 cells and to determine the molecular prerequisites for this effect. Methodology: A range of APP molecular constructs were stably expressed in DU145 cells and their effects on EMT were monitored by morphological analysis and by immunoblotting for the EMT marker proteins, E-cadherin and vimentin. Results: Our results show that the full-length 695 amino acid isoform (APP695), but not APP751 or APP770, promoted EMT via a mechanism requiring an intact extracellular E1 copper binding domain and tyrosine687 within the cytosolic domain of the protein. Conclusion: Targeting the expression of APP695 or the E1 copper binding domain of the protein may, therefore, contribute to therapeutic strategies for the delay or prevention of prostate cancer metastasis.