The Research To The Mechanism Of Curcumin Induces Autophagy In Human Medulloblastoma Daoy Cell

Objective: To investigate the mechanism of curcumin-inducedautophagy in human medulloblastoma Daoy cells.Methods: Ultrastructure change of Daoy cell was observed bytransmission electron microscopy after curcumin treatment. Expression ofautophagic markers Beclin1and LC3were assessed by fluorescenceconfocal microscopy, RT-PCR and Western blot. Expression of PI3K, Akt,p-Akt, mTOR and p-mTOR in PI3K/Akt/mTOR signal pathway werechecked by Western blot. After pre-treated with autophagy inhibitorwortmannin and PI3K agonist insulin respectively, expression ofautophagic markers and PI3K/Akt/mTOR signal pathway proteins weredetected by Western blot.Results: Transmission electron microscopy results showed thatautophagic vacuoles increased significantly after treated with curcumin.Immunofluorescence staining showed the intensity of the expression ofBeclin1and LC3in treated group was significantly higher than that incontrol group. RT-PCR showed that the expression of Beclin1mRNA andLC3mRNA in treated group (24h and48h) was significantly higher than that in control group and the difference was statistically significant(F=1360.962，42.366，P <0.05). Western blot showed that the expressionof Beclin1and LC3-Ⅱ/LC3-Ⅰ in treated group (24h and48h) wassignificantly higher than that in control group (0h),while the expression ofPI3K、p-Akt and p-mTOR in treated group was lower than that in controlgroup,and the difference was statistically significant (F=32.723，11.847，329.662，80.638，183.536，P<0.05).Curcumin-induced autophagy couldnot be reduced by wortmannin. Insulin could not reverse the inhibition ofPI3K/Akt/mTOR induced by curcumin.Conclusion: Curcumin could inhibit the growth of humanmedulloblastoma Daoy cells via autophagy. The mechanism of curcumin-induced autophagy in Daoy cells may be related to the inhibition ofPI3k/Akt/mTOR signaling pathway.