RESUMEN
OBJECTIVE To explore the antitumor effect and mechanism of total alkaloids of Gelsemium elegans （TA） and sempervirine （SPV） in vitro. METHODS The effects of low， medium and high concentrations of TA （50， 100， 200 μg/mL） and SPV （10， 30， 50 μmol/L） on the morphology of human hepatoma cells （HepG2， Bel-7402）， human lung cancer cells （A549） and human colon cancer cells （HCT-8） were observed， and the toxicity of TA and SPV to four tumor cells was monitored. The effects of TA and SPV on the contents of caspase-3 and caspase-9 in the supernatant of HCT-8 cells， the protein expressions of phosphorylated protein kinase B （p-Akt） （Thr308， Ser473）， B-cell lymphoma 2 （Bcl-2）， Bcl-2-related X protein （Bax）， survivin， C/EBP-homologous protein （CHOP）， immunoglobulin binding protein （Bip） and microtubule-associated protein 1 light chain 3Ⅱ （LC3Ⅱ） in HCT-8 cells were detected. RESULTS After the intervention of TA and SPV， the volume reduction and nuclear shrinkage were founded in four tumor cells； the cell activity decreased to varying degrees， among which TA and SPV had the best inhibitory effect on HCT-8 cells. After the intervention of TA and SPV， the contents of caspase-3 and caspase-9 in the supernatant of HCT-8 cells， the protein expressions of Bax， CHOP， Bip and LC3Ⅱ all increased to different degrees， while the protein expressions of p-Akt （Thr308， Ser473）， Bcl-2 and survivin in HCT-8 cells all decreased to different degrees. CONCLUSIONS TA and SPV have inhibitory effects on the above four tumor cells， and the inhibitory effect on HCT-8 cells is the best. The mechanism of their action on HCT-8 cells may be related to promoting apoptosis， activating endoplasmic reticulum stress and autophagy.
RESUMEN
Sempervirine, a yohimbane-type alkaloid isolated from Gelsemium elegans, was found to significantly inhibit the cellular proliferation of U251 cells in vitro and in vivo in a dose-dependent manner. U251 cells were treated with 0-16 μmol·L-1 of sempervirine for 24, 48 or 72 h. An MTT assay and clone formation assay were used to investigate cell survival and clone formation. Hoechst staining and Annexin V-FITC/PI staining were used to measure cell apoptosis. The expression of PI3K, AKT, p-AKT, Bax, Bcl-2, caspase-3 and cleaved caspase-3 was determined by Western blot analysis. The antitumor effect of sempervirine in vivo was investigated by inoculating nude mice with U251 cells. All animal experiments were in strict accordance with the regulations of the Biomedical Ethics Committee of Fujian Medical University (Fujian, China). The results show that sempervirine significantly inhibits the proliferation and induces the apoptosis of U251 cells, promotes cleavage of caspase-3, down-regulates the protein expression of PI3K and Bcl-2/Bax, and inhibits phosphorylation of AKT in vitro. Intraperitoneal injection of 4 or 8 mg·kg-1·day-1 of sempervirine inhibits U251 cells tumor growth in the xenograft nude mice, and tumor weight decreased by 44.76% and 61.26%, respectively. Our study shows that sempervirine significantly inhibits the proliferation of U251 cells in vitro and in vivo, laying a foundation for further research and development of its anti-glioma effect.