Abstract B55: Tumor-derived MCP-1 regulates invasiveness in triple-negative breast cancer via the MAP kinase pathway

Background : Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer compared to other breast cancer subtypes. The frequency of TNBC expression is highest in young African-American women, leading to significant cancer health disparity in this population. Furthermore, TNBC is difficult to treat due to lack of known receptor targets at protein or gene level. Hence, it is imperative to identify novel therapeutic strategies for treatment of TNBC. Here we aim to show that the Monocyte Chemoattractant Protein -1 (MCP-1) is a reliable biochemical marker to assess TNBC progression. Experimental Design : We employed ELISA method to measure secreted MCP-1 in cell conditioned media, and real-time PCR to determine the mRNA status of MCP-1 in different TNBC cell lines. Boyden chamber assay was used to determine the effect of recombinant MCP-1 on cellular invasiveness. Immunohistochemistry staining was utilized for detecting protein of interest in tissue samples from breast cancer patients. MCP-1 knockdown was performed using lentiviral vector with shRNA targeting MCP-1 coding regions. RNAseq was performed with recombinant human MCP-1. Results : Our data show that MCP-1 is upregulated in TNBC cell lines, both transcriptionally and in secreted protein levels compared to ER-positive cell line, MCF-7. Breast cancer patients also showed high expression of MCP-1. MCP-1 treatment induced MDA-MB-231 and MCF-7 cell invasion, without affecting cell proliferation. Small-molecule antagonists against chemokine receptor 2 (CCR2), cognate receptor for MCP-1, and the MAP kinase pathway inhibitor U0106 negatively affected MDA-MB-231 cell invasion as measured by the Boyden chamber assay. This suggests that MCP-1-CCR2 axis may regulate invasiveness via the MAP kinase pathway. Knocking down MCP-1 by shRNA decreased cell invasion in TNBC cell line, BT-549, along with downregulation of key epithelial-to-mesenchymal transition markers, N-cadherin and Vimentin. Recombinant MCP-1 treatment in TNBC MDA-MB-231 cells upregulated genes associated with cytokine signaling. Conclusion : Our study suggests that a high MCP-1 level in TNBC cells may be responsible for increase in cell invasion via the MAP kinase pathway. Thus, MCP-1-mediated pathways could be potential therapeutic targets for the treatment of TNBC and reduce cancer health disparities. Citation Format: Pranabananda Dutta, Kimberly Paico, Yanyuan Wu, Marianna Sarkissyan, Jaydutt Vadgama. Tumor-derived MCP-1 regulates invasiveness in triple-negative breast cancer via the MAP kinase pathway [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr B55.