A141
CCL21 neutralising antibody as a potential inhibitor of metastatic chemotaxis
Silvia Lanati, Maxine Emmett, Darryl Dunn, David Bates
University of Bristol, UK
Background
To determine whether inhibition of the CCR7/CCL21 pathway prevents direct chemotactic migration of human melanoma cells towards lymphatics.
Method
Metastatic human melanoma cells A375, a non-metastatic clone A375P transfected with CCR7 and human lymphatic endothelial cells (LEC) were used, the former seeded onto 8μm pore inserts and cells migrated across the membrane towards LEC conditioned media or recombinant human CCL21 counted. Nude mice were injected subcutaneously with 106 A375 cells 10mm rostral to the injection site of 105 LECs. Mice were treated with subcutaneous injections, among cell depots, with 5μg/ml of CCL21 neutralising antibody or 5μg/ml of goat IgG as control, 3 times in the first week and 2 times/week for the following weeks. Measurements were made from prosections of the tumour area relative to the EC injection site.
Results
It has previously been shown that A375 cells migrate toward LECs in vitro, while A375P cells do not [1]. To determine whether the lack of migration of A375P cells could be rescued by CCR7 expression, A375P CCR7 cells were seeded into a modified Boyden chamber. Migration towards LEC CM was only 3411% (meanSEM) when A375P CCR7 cells were treated with CCL21nAb and only 192.5% of that migrated towards rhCCL21 medium-rich in the presence of the CCL21nAb.
In vivo, A375 tumours migrated towards LECs (83.53% of tumour on EC side of injection) but A375 cells migration was strongly reduced in mice that had been treated with CCL21nAb (8.76%), which was less migration than observed with goat IgG.
Conclusion
These findings show that CCL21 neutralising antibody inhibits tumour-lymphatic interaction, prevents directed metastatic chemotaxis and may therefore be a potential therapeutic strategy to prevent lymphatic melanoma metastasis.
Acknowledgements
Supported by Wellcome Trust
References
[1] Shields et al. Oncogene, 2007
