Sugiol, a natural compound with anticancer properties, has shown promise in various cancer types, but its potential in preventing gastric cancer remains uncertain. In this study, we aimed to examine the inhibitory effect of sugiol on human gastric cancer cell proliferation. Our findings demonstrate that sugiol effectively suppresses the proliferation of SNU-5 human gastric cancer cells, leading to apoptotic cell death. We assessed the chemo-preventive potential of sugiol via an MTT assay and confirmed the induction of oxidative stress using the H2DCFDA fluorescent dye. Treatment with sugiol at concentrations higher than 25 µM for 24 h resulted in an increase in intracellular levels of reactive oxygen species (ROS). This elevation of ROS levels inhibited cell-cycle progression and induced cell-cycle arrest at the G1 phase. Furthermore, our study revealed that sugiol reduces the viability and proliferation of SNU-5 cells in a dose-dependent manner. Importantly, ADME and toxicity analyses revealed that sugiol was effective and nontoxic at low doses. In parallel, we utilized the Swiss target prediction tool to identify potential targets for sugiol. Enzymes and nuclear receptors were identified as major targets. To gain insights into the molecular interactions, we performed structure-based molecular docking studies, focusing on the interaction between sugiol and STAT3. The docking results revealed strong binding interactions within the active site pocket of STAT3, with a binding affinity of -12.169 kcal/mole. Sugiol's -OH group, carbonyl group, and phenyl ring demonstrated hydrogen-bonding interactions with specific residues of the target protein, along with Vander Waals and hydrophobic interactions. These data suggest that sugiol has the potential to inhibit the phosphorylation of STAT3, which is known to play a crucial role in promoting the growth and survival of cancer cells. Targeting the dysregulated STAT3 signaling pathway holds promise as a therapeutic strategy for various human tumors. In combination with interventions that regulate cell cycle progression and mitigate the DNA damage response, the efficacy of these therapeutic approaches can be further enhanced. The findings from our study highlight the antiproliferative and apoptotic potential of sugiol against human gastric cancer cells (SNU-5). Moreover, the result underpins that sugiol's interactions with STAT3 may contribute to its inhibitory effects on cancer cell growth and proliferation. Further research is warranted to explore the full potential of sugiol as a therapeutic agent and its potential application in treating gastric cancer and other malignancies characterized by dysregulated STAT3 activity.
Keywords: caspase cascade; cell-cycle arrest; human gastric cancer; inflammation; oxidative stress; sugiol.