MET, WNT and chemokines in tumour invasion
The emergence of MET and the chemokine system as key signals during tumour invasion and extravasation has raised the question of a functional interaction between these pathways in metastasis. The third way- a WNT pathway, is known to play a role in the behaviour of cancer cells of epithelial origin causing loss of epithelial features, multipolar shape and increased motility. This work addresses the question of whether the MET, WNT and chemokine receptor signalling pathways cooperate in metastasis.
- Mechanistic aspects investigating the co-operative effect of c-Met, WNT/β-catenin and chemokine receptor signalling in breast cancer cells.
A panel of human breast cancer cell lines will be screened first for expression of MET, β-catenin and the chemokine receptor CXCR4 and appropriate lines will be used for studies of adhesion, motility, invasion and activation of the Ras, MAPK and WNT pathways. To address the cooperation effect in vivo, tumour lines over-expressing MET, β-catenin and CXCR4 will be introduced in SCID mice. The deriving tumours will be analysed for their invasive and metastatic phenotype.
- Genetic evidence for crosstalk between MET, WNT/ β-catenin and chemokine receptor signalling in vivo
- Compound of transgenic mouse models to study breast cancer metastasis
In a complementary approach, a compound transgenic model will be developed in order to investigate the role of the HGF/SF-MET, WNT/β-catenin and chemokine signalling pathways during the development of breast cancer. Advances in genetic engineering have allowed precise control in the timing of the gain or loss of gene function mutations, their tissue selectivity and targeting to particular cell types in the transgenic mouse.
In our model we propose to utilise Cre/loxP recombinase-mediated somatic gene activation to cross the well-established gain-of-function β-cateninexΔ3 transgenic line, with the specific whey acidic protein (Wap)-Cre line for targeted expression in mammary epithelial cells. Previous reports have suggested that recombination mediated by Cre under the control of the Wap gene promoter is largely restricted to the mammary gland, unlike the mouse mammary tumour virus (MMTV)-driven promoter. This cross will then be combined with the HGF/SF-WAP transgenic mouse and finally with the CXCL12 knock-in mice. Each individual transgenic line will be characterised for effects on mammary development and tumourigenicity.
- Evaluation of transgenic metastatic mouse models
The different groups of mice described above will be studied for mammary tumour formation and tumour spread to distant organs. Tumours will be analysed for size, vasculature, invasion of the surrounding tissue and metastasis.
- Compound of transgenic mouse models to study breast cancer metastasis