Huntington disease protein accelerates tumour development and metastasis. Mus musculus

Huntington disease is a severe neurological disorder caused by an abnormal polyglutamine expansion in the N-terminal of the huntingtin protein. Here we show that breast tumours appear earlier when mutant huntingtin is expressed in an activated polyomavirus middle T antigen (PyVT) mouse breast cancer model as compared to the control mice expressing wild-type huntingtin. Tumours bearing mutant huntingtin have a modified gene expression pattern revealing increases in the IGF-1/Akt signalling, epithelial-mesenchymal transition and metastatic properties. Indeed, polyQ-huntingtin expressing tumours show hyper-activation of Akt pathway. Also, when mutant huntingtin is expressed, cancer cells in culture change morphology and the levels of cell adhesion and mesenchymal markers are affected in primary tumour or corresponding derived cells. As a consequence, PyVT induced lung metastasis is higher in Huntington disease mice than in the control mice. Finally, analysis of cases of Huntington disease patients developing breast cancer may suggest an increased aggressiveness of breast cancer when compared to the control population. Overall design: 8 Total samples were analyzed: 4 x MMTV-PyVT/HdhQ7/Q7 breast tumours; 4 x MMTV-PyVT/HdhQ111/Q111 breast tumours;