Ponicidin Induces Apoptosis and Inhibits Tumor Growth in C666-1 Nasopharyngeal Cancer Cells

Background Nasopharyngeal carcinoma (NPC), predominant in Southern China and Southeast Asia, is a malignant tumor that arises from the epithelial lining of the nasopharynx. Current NPC treatments result in unfavorable side effects. Natural compounds with anti-proliferative capabilities are gaining popularity as a way to mitigate the toxicity of radiation and synthetic antitumor drugs. Ponicidin, an ent-kaurane diterpenoid, has been demonstrated to possess several pharmacological activities, including antitumor, antibacterial, immunoregulatory, antiviral, and anti-inflammatory properties. Materials and Methods In the current investigation, the anti-carcinogenic activity of Ponicidin against nasopharyngeal cell line C666-1, has been investigated. The influence of Ponicidin on cell viability, apoptotic induction, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) generation, and apoptotic markers has been examined. Doxorubicin was selected as the positive control for the experiments. Results The effect of Ponicidin on the viability of C666-1 cells revealed that its cytotoxic potential increased in a dose-dependent pattern and the optimum concentration chosen for further experiments was 7.5 µM. The Ponicidin-treated cells demonstrated a significant increase in the amount of TBARS, whereas it reduced the activity of superoxide dismutase (SOD) and glutathione (GSH) levels, indicating augmented oxidative stress and lower antioxidant activity in the C666-1 cells. The acridine orange/ethidium bromide (AO/EtBr) staining technique was used to assess morphological changes with respect to apoptosis, which confirmed its apoptotic nature. Furthermore, Ponicidin elevated the ROS generation, modified the mitochondrial membrane permeability, elevated the apoptotic marker levels (caspase-3, caspase-9, and Bax) and reduced the Bcl-2 expression in C666-1 cell lines. Conclusion The findings suggest that Ponicidin successfully inhibited cancer cell proliferation by following the mitochondrial apoptotic pathway and thus could be effectively utilized as a potent anti-cancer agent for the treatment of nasopharyngeal cancer.