ABSTRACT
Background: The hedgehog (HH) signaling pathway is abnormally activated in glioblastoma (GBM); thus, its downstream effector GLI1 may be a suitable target for the treatment of GBM. The aim of the present study was to evaluate the antitumor activities of a novel compound, FL34, in GBM through the inhibition of GLI1. Methods: The effect of FL34 on suppressing the proliferation, angiogenesis, and invasion of GBM cells was investigated in vitro using proliferation, invasion, tube formation, flow cytometry, GLI1 dual luciferase, reverse transcription-quantitative polymerase chain reaction, and western blot assays. A subcutaneously transplanted and orthotopic U-87 MG GBM cell xenograft model was used to study the effect of FL34 on tumor growth in vivo. Results: The results of the present study demonstrated that FL34 markedly inhibited the proliferation, invasion, and angiogenesis of GBM, in addition to decreasing the transcriptional activity and expression of GLI1, resulting in the downregulation of GLI1 target genes, including B-cell lymphoma-2, vascular endothelial growth factor, and matrix metalloproteinases. Furthermore, FL34 inhibited the activation of GLI1 without influencing upstream canonical HH/Smoothened signaling or through crosstalk with other oncogenic pathways, including Ras/ERK and AKT signaling. At a dose of 30.0 mg/kg, FL34 suppressed tumor growth by 78.74% in tumor weight in subcutaneously transplanted U-87 MG xenograft models and by 64.24% in volume in orthotopic U-87 MG GBM xenograft models. Conclusions: These data suggested that FL34 exerted antitumor activity mediated by the inhibition of GLI1 and that FL34 may be a potential antitumor candidate compound that could be used to develop new antitumor drugs for the treatment of GBM
ABSTRACT
OBJECTIVE Evidience appears that parthenolide (PN) induces anti-tumor effects by NF-κB signal pathway. MCL3 the derivative of PN,is sesquiterpene lactone synthesized by the group of Professor Pan Xiandao.The study was to explore the anti-tumor activity and mechanism of MCL3 in glioma. METHODS The effect of MCL3 on the proliferation of glioma cell lines was examined by MTT assay. Apoptotic activity was investigated by flow cytometry. The Transwell cell invasion assay was used to determine the effect of MCL3 on the G422 cell invasive ability.The effect of MCL3 on the angio-genesis was analyzed by a capillary-like tube formation assay. The subcutaneously transplanted and orthotopic G422 cell xenograft models were used to detect the effect of MCL3 on tumor growth in vivo. The pathological changes were analyzed by H&E staining. Protein level related to the NF-κB signal pathway was dertimined by Western blotting. The effect of MCL3 on the NF-κB transcriptional activity was examined by a dual-luciferase reporter assay.RESULTS The anti-proliferative activity was observed following treatment with MCL3 for 96 h in G422, U-87 MG, U251 and Hs683 cell lines, and the IC50 was 8.94 μmol·L-1,6.44 μmol·L-1,14.8 μmol·L-1,18.9 μmol·L-1,respectively.The percentage of apop-totic cells increased in MCL3-treated G422 cells,and the apoptosis rate was 26.4%(the apoptosis rate was 5.68% in control group).MCL3 could inhibit the invasion in G422 cells,and the invasive inhibition rate was 43.63%(P<0.01)at 10.0 μmol·L-1.MCL3 inhibited tube formation of EA.hy926 cells,and the inhibitory rate was 81.67%(P<0.01)at 10.0 μmol·kg-1.At 40.00 mg·kg-1,MCL3 supressed tumor growth by 79.03% (P<0.01) in tumor weight in subcutaneously transplanted G422 xenograft models, and by 69.97% (P<0.01) in volume in orthopotic G422 xenograft models. H&E staining demonstrated that MCL3 could decrease tumor angiogenesis and invasion, increased necrosis of tumor cells. The dual-luciferase reporter assay showed that MCL3 inhibited NF-κB transcriptional actvity, and the inhibition rate was 50.07%(P<0.05)at 10.0 μmol·L-1compared with control.Moreover,MCL3 inhibited the phos-phorylation of NF-κB in nuclear mediated by supression of phosphorylated IKKα/β and IκB,and decreased the expression of IL-6 regulated by NF-κB.Eventually,the phosphorylation of State3 decreased following the administration of MCL3, resulting in the downregulation of State3 taget genes, including HIF, VEGF,FAK,MMP-2,MMP-9,Bcl-2 and Bcl-xL.CONCLUSION The anti-tumor effect of MCL3 was partly due to the inhibition of NF-κB/IL-6/State3 pathway in glioma.