Coffee Extracts and Chlorogenic Acid Inhibit the Proliferation of HepG2 Cells and c-Myc Expression Without Significant Modulation of Wnt/β-Catenin Signaling

Background: Hepatocellular carcinoma (HCC) is the most common type of liver cancer and is associated with poor clinical prognosis and high mortality, despite the advances related to therapeutic options for HCC. Therefore, exploring alternative therapeutic options and their associated mechanisms is relevant and urgently needed. Natural products may be an important source of novel anti-cancer compounds. Coffee consumption is associated with protective effects against liver diseases, but the molecular mechanisms underlying these benefits remain poorly understood. Objectives: In this study, we evaluated the in vitro effects of green (GC) and roasted coffee (RC) extracts, alongside chlorogenic acid (CGA), on the proliferation of HepG2 hepatocellular carcinoma cells. Results: Both coffee extracts and CGAs significantly reduced HepG2 cell viability and cell proliferation in a dose-dependent manner. GC at 500 µg/mL and CGA at 400 and 800 µM significantly induced caspase-3 activity. In addition, HepG2 cells treated with coffee extracts (500 and 1000 µg/mL) resulted in dose-dependent membrane permeabilization, leading to an increased number of necrotic cells. Despite these anti-proliferative effects, TOP/FOP luciferase assays revealed minimal activation of the Wnt/β-catenin signaling pathway. Among canonical Wnt target genes, only c-Myc expression was notably downregulated after treatment. Moreover, β-catenin protein levels and subcellular localization remained largely unchanged. Conclusions: These findings suggest that coffee extracts and chlorogenic acids inhibit HepG2 cell proliferation, highlighting their hepatoprotective properties, even in cells containing mutations that constitutively activate Wnt signaling.