Sulforaphane Modulates Cytokine Levels in Cell Culture Media of Triple-Negative Breast Cancer Cells Grown with Macrophages

Abstract

Objectives Triple negative breast cancer (TNBC) makes up approximately 10–20% of all breast cancer cases and is more common in younger women and in Hispanic and African American populations. It is particularly difficult to treat, exhibiting high-metastasis rates, poor prognosis, and limited treatment options. Mortality from TNBC is largely due to the tumor cells high invasive capacity and rapid progression to metastasis. Evidence suggests that macrophages in the breast tumor microenvironment release cytokines that increase tumor cell proliferation, invasion and metastasis. Sulforaphane (SFN) is a broccoli phytochemical that has been identified to slow the progression of breast cancer as well as alter cytokine secretion from macrophages and breast cancer cells grown in single culture. SFN effects on cytokine secretion in the breast tumor microenvironment remain unclear. This study is investigating the effect of SFN on cytokine levels in cell culture media of TNBC cells grown with and without macrophages. Our hypothesis is that cytokine levels differ in media from cocultured cells versus singly cultured cells, and SFN treatment further alters cytokine levels in media. Methods In this study, TNBC cells (MDA-MB-231) were grown in transwell plates with and without macrophages (THP-1 cells differentiated with phorbol-myristate acetate). Cell cultures (n = 3) were treated with either 15 µM SFN, DMSO (vehicle-control), or a non-treatment control. We evaluated the levels of 44 individual cytokines in cell culture media at 24 and 48 hours after treatment using a multi-plex (BioPlex) assay. Control groups included single-cultured MDA-MB-231 and differentiated THP-1 cells. Results Preliminary analyses revealed that cytokine levels differed in the media of single versus cocultured cells and among treatment groups after 24 and 48 hours of treatment. Conclusions The profile of cytokines in the media of TNBC cells grown with macrophages was influenced by SFN treatment. This information may help establish mechanisms underlying SFN effects on TNBC behavior and identify new treatment strategies. Funding Sources California State University Program for Education and Research in Biotechnology, California State University-Chico.