Study On Anti - Angiogenesis And Its Chemical Composition Of Euphorbia

Objective: Euphorbia species are rich sources of anti-cancer active ingredients and have varied framework, which is beneficial to the discovery of the leading compounds.Pharmacologically, Euphorbia prostrate aiton, one of the Euphorbia species, were reported to show the anti-inflammatory, anthelmintic and anti-diarrhea activities. But its anti-cancer function has never been demonstrated yet. Therefore, the present study was designed to investigate the anti-cancer and the anti-angiogenic effects of Euphorbia prostrate aiton. The involved mechanisms were also studied. In addition,the chemical constituents of Euphorbia prostrate aiton were preliminarily with the expectation to provide some experimental basis for the future in-depth studies.Methods: Firstly, the alcohol extract of Euphorbia prostrata aiton was prepared. The acute toxicity test was performed in mice to measure the tolerated dose of Euphorbia prostrata aiton. Secondly, the anti-proliferative effects of the alcohol extract of Euphorbia prostrata aiton on tumor cells were analysized by performing MTT assay.Meanwhile, rat aortic endothelial cells(RAECs) were primarily cultured and the i CELLigence real time cell analysis system was used to study the anti-proliferative effects of the alcohol extract of Euphorbia prostrata aiton on RAECs. In addition, the anti-migration and anti-tube formation effects of Euphorbia prostrata aiton on RAECs were also investigated. The protein expressions of Akt, p-Akt, e NOS, p-e NOS,TGF-β1 and Smad3 in the RAECs were detected by performing western blotting analysis. Moreover, after the transplanted human hepatocellular carcinoma model in nude mice was established, the body masses, tumor volumes and tumor weights were evaluated. The contents of vascular endothelial growth factor(VEGF) and platelet-derived growth factor-BB(PDGF-BB) in the serum from the model mice were also detected. The morphology of the tumor tissues from mice were also determined by performing HE staining. Finally, the chemical compositions of the 80%alcohol extract of Euphorbia prostrata aiton were further separated and prepared for the detections of their anti-tumor activities.Results: The tolerated dose of the alcohol extract from Euphorbia prostrata aiton for mice was 94.29g/Kg. The alcohol extract of Euphorbia prostrata aiton showed no inhibitory effect on normal cell(L6 cell) but significantly inhibited the proliferations of cancer cells, such as Hep G-2, PC12, A549 and Hela cells, with the following order:Hep G-2 cells>Hela cells >PC12 cells>A549 cells. Meanwhile, the alcohol extract from Euphorbia prostrata aiton markedly suppressed the proliferation, migration and tube formation of RAECs by activating the Akt-e NOS pathways and the TGF-β1-Smad3 pathways. Simultaneously, the treatment with alcohol extract of Euphorbia prostrata aiton notably inhibited the tumor growth, decreased the content of VEGF in nude mice serum but increasedthe amount of PDGF-BB factor. In terms of chemical compositions separation, five compounds were isolated and identified from the 80% alcohol extract of Euphorbia prostrata aiton: lupeol acetate, lupeol,phytol, β-sitosterol, 9,12,13-trihydroxy-10-trans-octadecenoicacid and9,12,13-trihydroxy-10-trans-octadecenoicacid. Significant inhibitory effects on the proliferation, migration and tube formation of RAECs were also observed in the presence of 9,12,13-trihydroxy-10-trans-octadecenoicacid with the activations of the Akt-e NOS and the TGF-β1-Smad3 pathways.Conclusion: The alcohol extract of Euphorbia prostrata aiton and9,12,13-trihydroxy-10-trans-octadecenoicacid isolated from Euphorbia prostrata aiton may have significant inhibitions on the tumor growth and the angiogenesis,which may contribute to their anti-tumor effects.