Anti-neoplastic effects of Chrysanthemum indicum extract on a human hypopharyngeal squamous cell carcinoma cell line

Abstract

Hypopharyngeal squamous cell carcinoma (HSCC) is an aggressive malignancy associated with poor clinical outcomes and limited therapeutic options. Natural products, such as Chrysanthemum indicum (CI) extract, represent potential candidates for anticancer drug development; however, their therapeutic potential against HSCC remains unclear. The present study investigated the antitumor activity of CI crude extract in the human HSCC cell line FaDu and explored the underlying molecular mechanisms. Intracellular oxidative activity following CI treatment was quantified using 2′,7′-dichlorodihydrofluorescein diacetate flow cytometry. The expression of proteins associated with cell survival and apoptosis was evaluated using western blotting, while cell viability was assessed using a Cell Counting Kit-8 assay. CI treatment notably reduced FaDu cell viability in a dose- and time-dependent manner. Flow cytometric analysis revealed an acute, concentration-dependent increase in intracellular oxidative activity following CI treatment, which was effectively reversed through pretreatment with the antioxidant N-acetylcysteine. Increased intracellular oxidative activity was accompanied by reduced expression of the endoplasmic reticulum stress sensor protein kinase R-like endoplasmic reticulum kinase, also known as eukaryotic translation initiation factor 2 α kinase 3 (EIF2AK3), decreased phosphorylated (p)-Akt levels and a reduced p-Akt/total Akt ratio. These changes were accompanied by marked dose-dependent depletion of the anti-apoptotic protein B-cell lymphoma 2. Overall, CI treatment reduced FaDu cell viability and was associated with increased intracellular oxidative activity, reduced EIF2AK3 expression and decreased Akt activation. These findings support the potential antitumor activity of CI in HSCC cells and provide a rationale for further mechanistic and in vivo investigation.