Abstract P4-04-27: Chemokines released by breast cancer-associated fibroblasts induce epithelial to mesenchymal transition in MCF7 breast cancer cells

Abstract

Abstract Purpose: The tumour microenvironment plays a critical role in tumour progression, with cancer-associated fibroblasts (CAFs) in particular being involved in this process (1). Treating breast cancer cells with conditioned media from CAFs has been shown to induce epithelial-mesenchymal transition (EMT) of the breast cancer cells compared to conditioned media from normal breast fibroblasts (NBFs) (2). This study aims to identify factors released by CAFs which induce EMT in breast cancer cells. Methodology: Primary cultures of six pairs of CAFs and NBFs were established from breast cancer patient samples. Serum-free conditioned media from these cells were collected for chemokine array analysis. MCF7 breast cancer cells were treated with recombinant chemokines and their corresponding receptor antagonists. Vimentin levels, as determined by immunoblot, and cell invasiveness, as measured by transwell assay, were used as indicators of EMT. Results: Chemokine array showed that CAFs secreted more CXCL1, CXCL8, CXCL12 and CCL2 compared to matched NBFs. Recombinant CXCL8, CXCL12 and CCL2, but not CXCL1, were able to induce vimentin and to increase invasiveness in MCF7 cells. Antagonists for receptors of CXCL8, CXCL12 and CCL2 counteracted the effect of EMT induction on MCF7 cells by recombinant chemokines. Conclusion: CXCL8, CXCL12 and CCL2, which are secreted at higher levels by CAFs compared to NBFs, induced EMT and increased invasiveness in MCF7 cells. These results suggest that therapeutic targeting of these chemokines or their receptors may be inhibitory to metastasis in some breast cancers.