Effects of cucurbitacin B on cell proliferation and apoptosis in Hep-2 cells / 临床耳鼻咽喉头颈外科杂志

ABSTRACT

OBJECTIVE@#To investigate the mechanism underlying the anticancer activity of cucurbitacin B on human laryngeal cancer.@*METHOD@#Hep-2 cells were treated with different concentrations of cucurbitacin B for different time. MTT assay was used to evaluate cell proliferation. Flow cytometry with PI staining and fluorescent microscopy with Hoechst 33258 staining were used to estimate cell cycle distribution and cell apoptosis. Expression of p-STAT3, cyclin B1 and Bcl-2 proteins was evaluated by Western blot assay. In vivo inhibitory effects of cucurbitacin B on tumor growth was evaluated in a nude mouse xenograft model.@*RESULT@#Cucurbitacin B inhibited cellular proliferation in a dose and time dependent manner (P <0.05 or 0.01). Flow cytometry analysis showed that treatment with cucurbitacin B resulted in accumulation of cells at the G2/M phase of the cell cycle and cell apoptosis in a dose and time dependent manner (P <0.05 or P <0.01). Marked morphological changes of cell apoptosis including condensation of chromatin, nuclear fragmentation and apoptotic bodies were observed clearly by Hoechst 33258 staining. Western blot analysis demonstrated that the expression of p-STAT3, cyclin B1 and Bcl-2 proteins was suppressed significantly. In vivo studies showed that the inhibitory rates on laryngeal squamous carcinoma xenograft model were 32.43%, 43.24% and 70.27% for lower, moderate and higher dosage group, respectively.@*CONCLUSION@#Cucurbitacin B inhibited cell proliferation and induced apoptosis of Hep-2 cells by suppressing STAT3 signal pathway, down regulating the expression of cyclin B1 and Bcl-2 proteins.