Transforming growth factor-β signalling controls human breast cancer metastasis in a zebrafish xenograft model
1 Department of Molecular Cell Biology, Cancer Genomics Centre Netherlands, Leiden University Medical Center, Postbus 9600 2300, RC, Leiden, The Netherlands
2 Centre for Biomedical Genetics, Leiden University Medical Center, Postbus 9600 2300, RC, Leiden, The Netherlands
3 Institute of Biology, Leiden University, Einsteinweg 55, 2333, CC Leiden, The Netherlands
4 Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Box 595, 75124 Uppsala, Sweden
5 Current address: Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
Breast Cancer Research 2013, 15:R106 doi:10.1186/bcr3573Published: 7 November 2013
The transforming growth factor beta (TGF-β) signalling pathway is known to control human breast cancer invasion and metastasis. We demonstrate that the zebrafish xenograft assay is a robust and dependable animal model for examining the role of pharmacological modulators and genetic perturbation of TGF-β signalling in human breast tumour cells.
We injected cancer cells into the embryonic circulation (duct of cuvier) and examined their invasion and metastasis into the avascular collagenous tail. Various aspects of the TGF-β signalling pathway were blocked by chemical inhibition, small interfering RNA (siRNA), or small hairpin RNA (shRNA). Analysis was conducted using fluorescent microscopy.
Breast cancer cells with different levels of malignancy, according to in vitro and in vivo mouse studies, demonstrated invasive and metastatic properties within the embryonic zebrafish model that nicely correlated with their differential tumourigenicity in mouse models. Interestingly, MCF10A M2 and M4 cells invaded into the caudal hematopoietic tissue and were visible as a cluster of cells, whereas MDA MB 231 cells invaded into the tail fin and were visible as individual cells. Pharmacological inhibition with TGF-β receptor kinase inhibitors or tumour specific Smad4 knockdown disturbed invasion and metastasis in the zebrafish xenograft model and closely mimicked the results we obtained with these cells in a mouse metastasis model. Inhibition of matrix metallo proteinases, which are induced by TGF-β in breast cancer cells, blocked invasion and metastasis of breast cancer cells.
The zebrafish-embryonic breast cancer xenograft model is applicable for the mechanistic understanding, screening and development of anti-TGF-β drugs for the treatment of metastatic breast cancer in a timely and cost-effective manner.