Co-culture system of breast cancer and normal cells to investigate inflammation: using doxorubicin encapsulated in adipose-derived exosomes

Abstract

Doxorubicin (DOX) chemotherapy for breast cancer is an effective treatment option, but it also has disadvantages. Exosomes (EXOs) have safely and successfully transported DOX and reduced its adverse effects; however, its use is still being explored. In this study, a co-culture system of malignant and non-malignant breast cells was used to generate an in vitro model reflecting the in vivo cellular microenvironment, and the effects of this treatment were investigated by examining inflammatory genes. Extracellular matrices (EXOs) were extracted from mesenchymal stem cells derived from human adipose tissue by ultracentrifugation. Later, Western blotting, dynamic light scattering (DLS) and transmission electron microscopy methods were used to examine the properties of the EXO. DOX was encapsulated in the EXOs by sonication and the loading rate was measured by spectrophotometry. In the current study, a co-culture system was used to investigate the cytotoxic effects of free DOX and DOX encapsulated in EXOs (EXO-DOX) on various breast cell lines, including MCF-7, MCF-10A, MDA-MB-231, and A-MSC. Additionally, the expression levels of inflammatory cytokines (IL-1β, IL-6, IL-10, and TNF-α) were examined. Methylthiazolyldiphenyl-tetrazolium bromide assay demonstrated that free DOX showed the highest cytotoxicity against MCF-10A cells, followed by MCF-7 cells. Conversely, EXO-DOX indicated a greater effect on MCF-7 cells and had a lower IC₅₀ compared to MDA-MB-231 cells. Free DOX significantly downregulated the expression of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), particularly in MCF-7 and MCF-10A cells, while concurrently upregulating IL-10 expression. EXO-DOX induced a more significant alteration in cytokine expression than the control and free DOX treatment groups. The co-culture system revealed a synergistic effect of free DOX on cancer cells while simultaneously mitigating the toxic effects of DOX on normal cells. This study suggests that EXO-DOX has promising potential as a targeted drug delivery system that could potentially improve therapeutic efficacy and minimize off-target toxicity.

Keywords: Breast cancer; Co-culture; Doxorubicin; Exosome; Inflammation.