1. ¹Breast Cancer Research Group, School of Surgical and Reproductive Sciences, Newcastle University, Newcastle-upon-Tyne, NE2 4HH, UK
2. ²Department of Chemical and Biological Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK

Correspondence: Professor JA Kirby, School of Surgical and Reproductive Sciences, 3rd Floor William Leech Building, Framlington Place, University of Newcastle, Newcastle-upon-Tyne NE2 4HH, UK. E-mail: J.A.Kirby@ncl.ac.uk

Received 8 May 2007; Revised 11 July 2007; Accepted 13 July 2007; Published online 28 August 2007.

Abstract

Expression of the chemokine receptor CXCR4 allows breast cancer cells to migrate towards specific metastatic target sites which constitutively express CXCL12. In this study, we determined whether this interaction could be disrupted using short-chain length heparin oligosaccharides. Radioligand competition binding assays were performed using a range of heparin oligosaccharides to compete with polymeric heparin or heparan sulphate binding to I¹²⁵ CXCL12. Heparin dodecasaccharides were found to be the minimal chain length required to efficiently bind CXCL12 (71% inhibition; P<0.001). These oligosaccharides also significantly inhibited CXCL12-induced migration of CXCR4-expressing LMD MDA-MB 231 breast cancer cells. In addition, heparin dodecasaccharides were found to have less anticoagulant activity than either a smaller quantity of polymeric heparin or a similar amount of the low molecular weight heparin pharmaceutical product, Tinzaparin. When given subcutaneously in a SCID mouse model of human breast cancer, heparin dodecasaccharides had no effect on the number of lung metastases, but did however inhibit (P<0.05) tumour growth (lesion area) compared to control groups. In contrast, polymeric heparin significantly inhibited both the number (P<0.001) and area of metastases, suggesting a differing mechanism for the action of polymeric and heparin-derived oligosaccharides in the inhibition of tumour growth and metastases.