Caffeic Acid Phenethyl Ester Suppresses Cytokine- and Chemotherapy-Induced Inflammation in Triple-Negative Breast Cancer via NF-κB Signalling

Background: Triple-negative breast cancer (TNBC) remains a significant clinical challenge due to its aggressive nature and lack of targeted therapies. In TNBC, inflammation contributes to tumour progression by promoting cell proliferation, survival, and migration. It may be triggered by cytokines such as TNF-α or chemotherapeutic agents such as doxorubicin (DOX). Thus, identifying agents that suppress inflammation in TNBC is of prime interest. Caffeic acid phenethyl ester (CAPE) is a naturally occurring anti-inflammatory compound that exhibits selective cytotoxicity against some cancer cells. However, its impact on cytokine or chemotherapy induced inflammation in TNBC has not yet been explored. Aim: This study aimed to investigate the effects of CAPE on TNF-α- or DOX-induced inflammation and metastatic markers in TNBC. Methods: The effects of CAPE and DOX on TNBC cell viability and migration were assessed using the MTT and wound healing assays, respectively. The effect of CAPE on the expression of pro-inflammatory cytokines, epithelial-mesenchymal transition (EMT) markers, and tumour invasion markers was evaluated using RT-qPCR. Results: CAPE inhibited TNF-α-induced proliferation and migration of TNBC cells. CAPE also suppressed TNF-α- and DOX-induced upregulation of NF-κB-regulated pro-inflammatory genes, IL-1B, IL-6, IL-8, and TNF-α, corroborating the evidence that CAPE suppresses NF-κB signalling. Additionally, CAPE suppressed EMT in TNF-α–stimulated and DOX-treated cells by downregulating vimentin and VCAM1. Furthermore, CAPE reduced the expression of the cancer invasion markers MMP2 and MMP9. Conclusions: We demonstrated the anticancer potential of CAPE and its ability to suppress cytokine and chemotherapy-induced inflammation. This study offers novel insights into the role of CAPE in suppressing inflammation and metastasis markers in TNBC, specifically in the context of TNF-α and DOX-induced NF-κB signalling. These findings underscore the urgent need to further study CAPE as a possible adjuvant for treating patients with TNBC, especially those undergoing chemotherapy.