Macrophage conditioned media promotes adipocyte cancer-association, which in turn stimulates breast cancer proliferation and migration
Abstract Background Breast cancer is the most common cancer in women and the leading cause of female cancer deaths worldwide. Obesity causes chronic inflammation and is a risk factor for post-menopausal breast cancer and poor prognosis. Obesity is known to trigger increased infiltration of macrophages into adipose tissue, yet little research has focused on the effects of macrophages in the early stages of breast tumor development in obese patients. In this study, the effects of pro-inflammatory macrophages on breast cancer-adipocyte crosstalk were investigated. Methods An innovative human cell co-culture system was used to model the paracrine interactions among adipocytes, macrophages, and breast cancer cells, and how they can facilitate tumor progression. The effects on human breast cancer cells were examined using cell counts and migration assays. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was used to measure the expression levels of several cytokines and proteases to analyze adipocyte cancer-association. Results Macrophage conditioned media intensified the effects of breast cancer-adipocyte crosstalk. More specifically, adipocytes became delipidated and increased production of pro-inflammatory cytokines, even in the absence of breast cancer cells, although the expression levels were highest with all three cell components. As a result, co-cultured breast cancer cells became more aggressive, with increased proliferation and migration potential when compared to adipocyte-breast cancer cell co-cultures treated with unconditioned media. Conclusions Macrophage conditioned media promotes adipocyte cancer-association and production of pro-inflammatory factors. These macrophage-adipocyte paracrine interactions promote human breast cancer cell proliferation and migration. Thus, macrophages may contribute to adipocyte inflammation and cancer-association and promote breast cancer progression.