Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer, and the majority of TNBC lacks targeted therapies. Previous studies have shown that TNBC cells are highly sensitive to TNF-related apoptosis-inducing ligand (TRAIL), making it a potentially viable treatment option for TNBC. However, the development of TRAIL resistance limits its potential for clinical use, and the underlying mechanisms are not fully understood. To better understand the mechanism of resistance to TRAIL, we performed RNA sequencing to identify the candidates that are responsible for resistance to TRAIL in two previously established TRAIL-resistant MDA231 and SUM159 cells. This approach led us to identify differentially expressed genes (DEGs) and pathways in TRAIL-resistant MDA231 and SUM159 cells compared to their TRAIL-sensitive counterparts. We showed that several DEGs and pathways were associated with inflammation in TRAIL-resistant cells, including IL-1α and IL6. By downregulating IL-1α and IL6 expression, we showed that TRAIL sensitivity can be significantly restored in TRAIL-resistant cells. Therefore, this study identifies a mechanism by which the inflammation pathway promotes TRAIL resistance, which could be targeted for enhancing TRAIL-based therapies in TNBC cells.
Keywords: TNBC; TRAIL; inflammation; resistance.
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