Cytokine Secretions in Partial Breast Tumor Microenvironment With and Without Sulforaphane

Abstract

Objectives Triple-negative breast cancer (TNBC) comprises 10–20% of breast cancer cases. It is particularly aggressive with limited and deleterious treatment options. Increasingly, research confirms that communication between cancer cells and neighboring macrophages promotes disease progression in part by secretion of cytokines that increase tumor cell proliferation, invasion, and metastasis. Sulforaphane (SFN) is a chemopreventive phytochemical found in cruciferous vegetables (broccoli) shown to alter cytokine secretion in macrophages and breast cancer cells grown in single culture. However, its effect in the tumor microenvironment remains unclear. This study aims to characterize cytokine profiles in media where TNBC cells and macrophages are grown in coculture with and without SFN treatment. We expect SFN to modify cytokine secretions in coculture media, suggesting SFN may disrupt vital cell-cell signaling needed for cancer progression. Methods TNBC cells (MDA-MB-231) were grown in Transwell plates with and without macrophages (THP-1 cells differentiated with PMA). Cell cultures (n = 3) were treated with either 15 μM SFN, DMSO (vehicle-control), or a non-treatment control. Cytokine levels were evaluated in media at 24 and 48 hours after treatment using BioPlex 2000 assay. Results Treatment with sulforaphane significantly reduced the levels of several targets in coculture including IL-1ra, IL-4, IL-5, IL-10, IL-12, IL-13, IL-15, IL-17, CCL2 (MCP-1), CCL11, CCL22, CCL26, CXCL12, IFN-y, G-CSF, GM-CSF, Eotaxin, and VEGF. Conversely, MIF was elevated following treatment. Effects were discovered at 24-hour and 48-hour time points. Conclusions We demonstrated that SFN altered the levels of numerous cellular signaling proteins in cancer cell-macrophage coculture, many of which are known to be involved with breast cancer progression. These results reveal mechanistic links underlying SFNs chemopreventive function and bolster SFNs potential as a treatment strategy for TNBC. Funding Sources Department of Nutrition and Food Science, CSU Chico; Graduate Studies, CSU Chico; CSUPERB: CSU Program for Education and Research in Biotechnology.