The xenografted zebrafish were treated with 50 nM of MMP2 ZD1839 9 Inhibitor II, a dose of the small molecular inhibitor found to cause minimal malforma tion and death, or a vehicle control for 6 dpi. The zebra fish embryo water was changed every second day. Inhibiting MMP2 and MMP9 halted the invasion of metastatic breast cancer cells in the embryonic zebrafish. GM6001 is an Inhibitors,Modulators,Libraries MMP inhibitor, also known as Galardin or Ilomastat, it has been shown to suppress invasion of MDA MB 231 cells in a three dimensional collagen spher oid assay, and MCF10A M4 cells. MDA MB 231 and the MCF 10 series were treated with or without the inhibitors for 24 h prior to transplant ation into the zebrafish embryo. Xeno grafted zebrafish were treated with the doses of the small molecular inhibitors found to be tolerable, or a vehicle control for 6 dpi.

The zebrafish embryo water was changed every second day. Targeting the TGF B pathway with small molecular inhibitors proved effective and reduced the invasion of the cancer cells. Discussion This study used the zebrafish xenograft assay by inject ing malignant breast cancer cells into the embryonic circulation, and monitoring their invasion Inhibitors,Modulators,Libraries into the avascu lar collagenous tail fin, as a robust and dependable animal model for examining the role of pharmacological modu lators and genetic perturbation of TGF B signalling in human tumour cells. Upon injection into the DoC, we observed that breast cancer cells dispersed immediately throughout the embryo via the circulating blood system, extravasated and invaded neighbouring tissue at specific tail fin sites and formed micrometastasis within 6 days.

We have shown that blocking the TGF B pathway using various methods of inhibition and at various stages of the pathway results in a signifi cant reduction of invasion and metastasis of breast cancer cells. Invasion and micrometastasis were only observed from breast cancer cells with metastatic potential. Interest ingly, we found that M2 and M4 cells formed Inhibitors,Modulators,Libraries clusters of invasive cells mainly in the CHT region, where they are capable of proliferation. In contrast, MDA MB 231 cells were visible as single cells that mi grated much more aggressively than M2 and M4 cells into the tail fin. It will be an interesting area of future re search to determine what determines the phenotypic dif ferences of cell migration.

A recent publication has shown that ectopic expression of Slug or Snail is capable of pro Smad4 KD moting invasion of single, rounded amoeboid cells in vitro. Furthermore, when M2 cells with Snail or Slug over expression were Inhibitors,Modulators,Libraries implanted into the embryonic zebrafish xenograft model, Inhibitors,Modulators,Libraries single cell invasion was also such information seen. This would suggest that epithelial to mesenchymal transition is a potential requirement for single cell migration into the tail fin.