Role of yap/taz on circulating tumour cells
Metastasis is the leading cause of all cancer-related deaths. Circulating Tumour Cells (CTCs) are cancer cells that shed off the primary tumour, enter into blood vessels and through the blood circulation are transferred to distant organs, whereby they establish new metastatic lesions. CTCs are detected as single cells and/or clusters of cells with clusters being more metastasis-prone than single CTCs. CTC clusters have different sizes varying from 2- to 50-cells. However, it still remains unknown if the different size of CTCs has an impact on their metastatic potential and what factors regulate their size. To elucidate the molecular dynamics of clustered CTC formation, we performed RNA-seq analysis in cells from primary tumours and CTCs and identified the YAP/TAZ gene signature to be upregulated in CTCs. YAP/TAZ is an interesting molecular node, as its function depends on its subcellular localisation. Junctional localised YAP/TAZ inhibits cancer cell dissemination by supporting the maintenance of cell-cell adhesions, while nuclear YAP/TAZ induces a genetic program that promotes cancer progression. We hypothesised that YAP/TAZ could play a critical role on CTC biology, regulating the size and metastatic potential of CTCs. Thus, the aim of this fellowship is to determine the impact of the size of clustered CTCs on establishing metastatic lesions and provide mechanistic insight on the role of YAP/TAZ. More specifically, I will determine: 1) the localisation of YAP/TAZ in CTCs from mouse models and patients with breast cancer, 2) if YAP/TAZ affects the size of clustered CTCs in breast cancer mouse models, 3) if YAP/TAZ localisation affects the metastatic potential of CTC clusters of variable sizes and 4) signals regulating the nucleocytoplasmic shuttling of YAP/TAZ in CTCs. Hence, this research could be the foundation for developing novel anticancer therapies and an improved patient stratification system.