Targeting the Tumor Immune Microenvironment in Triple-Negative Breast Cancer: The Promise of Polyphenols

Breast cancer remains a formidable global health challenge, with triple-negative breast cancer (TNBC) posing unique clinical complexities. Characterized by its aggressive nature and limited number of specific therapeutic targets, this breast cancer subtype disproportionately affects African American women, highlighting critical disparities in care. The tumor immune microenvironment (TIME) plays a critical role in breast cancer development and response to immunotherapy, and it is essential in fostering an immunosuppressive and pro-inflammatory niche. Inflammation, primarily mediated by the NF-κB signaling pathway and chemokine signaling, particularly involving CCL2, plays a pivotal role in TNBC progression and therapy resistance. This review describes some of the molecular mechanisms of polyphenols, which are naturally occurring compounds abundant in various dietary sources, and their potential use as therapeutic agents in the management of TNBC. Polyphenolic compounds have been described as modulating the TIME through the inhibition of tumor progression, immune evasion, and therapy resistance, due to their diverse bioactivities, including anti-inflammatory, antioxidant, and anticancer properties, making them attractive candidates for combating the aggressiveness of TNBC and addressing treatment disparities. Polyphenols, such as curcumin, gossypol, butein, epigallocatechin gallate, cardamonin, and resveratrol, have demonstrated efficacy in modulating several signaling pathways within the TIME, which are implicated in the progression of TNBC. This review highlights the potential effects of polyphenols on inflammatory cytokine release, programmed cell death ligand 1 (PD-L1) expression, which is associated with immune evasion by the host cell, and various intracellular signaling cascades, demonstrating their potential use in personalized therapeutic interventions for TNBC. This study also describes differential responses of TNBC cell lines to polyphenol treatment, highlighting the importance of considering genetic variability in therapeutic strategies, as well as the importance of the interaction of polyphenols with the gut microbiome, which may establish the bioavailability and effectiveness of these compounds toward therapeutic outcomes. Further preclinical and clinical studies are warranted to fully elucidate the therapeutic potential of polyphenols and translate these findings into clinical practice, thereby improving outcomes for patients with TNBC worldwide.