Cucurbitacins are compounds isolated from various plant families, which have been used as folk medicines for centuries in countries such as India and China because of their wide spectrum of pharmacological activities such as cytotoxic, anti-inflammatory, and anticancer effects. Accumulated evidences have shown that
cucurbitacin B inhibits the growth of numerous human
cancer cell lines and
tumor xenografts. To determine whether
cucurbitacin B can inhibit the growth of
laryngeal squamous cell carcinoma, in the present study we investigated the antitumor effect of
cucurbitacin B on Hep-2 cells. Hep-2 cells were treated with different concentrations of
cucurbitacin B for different time. Cell proliferation, cell cycle distribution, and cell apoptosis were evaluated using MTT assay, flow cytometry, and fluorescent microscopy. It was found that
cucurbitacin B exhibited significant efficacy in growth inhibition, cell cycle arrest at G2/M phase, and apoptosis induction in a dose- and time-dependent manner. Measuring the modulation of regulators in the cell cycle, apoptosis and signal transductions by Western blot analysis showed that the effect of
cucurbitacin B was due to suppression of the expression of p-STAT3, Bcl-2, and
cyclin B1. Moreover, in vivo studies were performed in a mouse xenograft model, where
cucurbitacin B inhibited
tumor growth in a dose-dependent manner. In conclusion, the antitumor effect of
cucurbitacin B on Hep-2 cells was due to the induction of cell cycle arrest as well as apoptosis. The possible mechanisms underlying the action might be attributed to the suppression of STAT3 phosphorylation. This investigation suggests a potential clinical application of
cucurbitacin B for the treatment of
laryngeal cancer patients.