Experimental study of curcumol inhibiting vascular endothelial growth factor-induced neovascularization / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To study the role and mechanism of curcumol in neovascularization induced by vascular endothelial growth factor(VEGF).METHODS: Human umbilical vein endothelial cells were cultured in vitro and treated with 50ng/mL VEGF and curcumol at different concentrations. Cell proliferation was detected by CCK-8 and EdU assay, the migration ability of cells was analyzed by Transwell assay, the angiogenesis ability of endothelial cells was analyzed by tube formation assay, and the change of Akt/mTORC1 signal pathway was detected by Western blot.RESULTS: CCK-8 results showed that the OD450 value of cells in 400 and 800 μmol/L curcumol+VEGF group was significantly lower than that in VEGF group(all P<0.01). EdU results showed that the rate of cell proliferation in 400 μmol/L curcumol+VEGF group was significantly lower than that in VEGF group(P<0.001). Transwell assay and the formation assay results showed that the number of migratory cells in 400 μmol/L curcumol+VEGF group was decreased, and the number and length of tube branches were also reduced compared with VEGF group(all P<0.001). Western blot results showed that curcumol significantly inhibited the expression of p-Akt and p-S6, which were downstream targets of Akt/mTORC1 pathway in cells.CONCLUSION: Curcumol can inhibit VEGF-induced cell proliferation, migration and tube formation of vein endothelial cells, and has a strong inhibitory effect on angiogenesis, which can be further studied in the treatment of ocular fundus neovascularization.

8-Azaguanine-induced autophagy contributes to its chemoresistance in hepatic cancer cells / 药学学报

Autophagy, an evolutionarily conserved process by which components of the cell are degraded in lysosomes, may facilitate survival of cancer cells under stress conditions. 8-Azaguanine (8-AG), an inhibitor of purine nucleotide biosynthesis, shows antineoplastic activity in multiple tumor cells. However, chemoresistance has restricted its development as an anticancer agent, and the mechanism of 8-AG resistance is not fully understood. We report here that 8-AG induces a protective autophagy to eliminate its cytotoxicity, and inhibition of autophagy increases cellular sensitivity of cancer cells to 8-AG treatment. Using HepG2 or SMMC-7721 hepatic cancer cell lines, we found that 8-AG inhibited cell viability and induced intrinsic apoptosis, accompanied by the up-regulation of the pro-apoptotic protein BimS, one of Bim (also known as BCL-2-like protein 11, BCL2L11) isoforms. Furthermore, 8-AG treatment enhanced the autophagy flux by promoting the dephosphorylation and activation of Unc-51-like autophagy activating kinase 1 (ULK1) via Akt/mTORC1 (mammalian target of rapamycin complex 1) signaling inhibition. Depletion of autophagy-related gene 7 (ATG7) markedly enhanced the level of BimS, and promoted cell death in response to 8-AG. 8-AG in combination with autophagy inhibitor chloroquine (CQ) or bafilomycin A1 (Baf A1) promoted the 8-AG-induced apoptosis in hepatic cancer cells. Altogether, these findings suggest that autophagy promotes chemoresistance of cancer cells for 8-AG, and blocking autophagy increases cellular sensitivity of cancer cells to 8-AG treatment.