IL-1β induces up-regulation of BIRC3, a gene involved in chemoresistance to doxorubicin in breast cancer cells.

Epithelial to mesenchymal transition (EMT) of tumor cells facilitates their progress to metastasis. In the tumor microenvironment the inflammatory cytokine 1β (IL-1β) has been associated with tumor development and invasiveness. IL-1β-induced EMT triggers the expression of markers associated with malignancy. We have recently reported that an IL-1β-highly responsive clone (6D cells) from non-invasive MCF-7 breast cancer cells activates PI3K/Rac and IL-1RI/β-catenin pathways that up-regulate the transcription of genes involved in an EMT-like process. However, a correlation between the EMT program induced by a pro-inflammatory environment, and the acquisition of chemoresistance has not been yet determined in these cells. In this work, we report the expression of cell survival genes after IL-1β stimulation of 6D cells. The expression of CDKN1A, TP63, SFN and, particularly, BIRC3 was found to be up-regulated in a RNA-seq analysis and validated by qPCR. Cells stimulated with IL-1β when challenged with doxorubicin showed resistance to the drug, whereas silencing of BIRC3 decreased viability of the cells treated with the drug. Our present results show that IL-1β confers doxorubicin resistance to breast cancer cells, underlining the importance of an inflammatory environment in cancer malignancy.