Effect Of MG132 On Cell Growth, Apoptosis And P27 Expression Of HeLa Cell

Objectives To investigate whether MG132 reduced the growth ofa human cervical carcinoma cell line HeLa cells through induction ofapoptosis in vitro. To observe the effect of MG132 on the expression ofp27.Methods (1) we observed the morphological features of apoptoticcells induced by MG132 with inverted microscope. (2)HeLa cells werecultured and treated by MG132 with 2.5μmol/l,5μmol/l,10μmol/l,20μmol/l,40μmol/l,80μmol/l and 160μmol/l concentrations for 24hours respectively.Cell viability were measured by MTT assay.At thesametime, HeLa cells were cultured and treated by MG132 With2.5μmol/l,5.0μmol/l,10μmol/l,20μmol/l,40μmol/l concentration for 48and 72 hours, The effect of MG132 on Hela cells were analyzed by MTTassay,respectively. (3) HeLa cells were cultured and treated by MG132with 2.5μmol/l,5μmol/l,10μmol/l,20μmol/l concentrations for 48h, theapoptotic rate of HeLa cells were analyzed by flow cytometry after PIstaining,respectively. Treated with 10μmol/l MG132 for 24,48 and 72hours, the apoptotic rate and cell cycle distribution were analyzed byflow cytometry after PI staining,respectively. (4) HeLa cells were treatedwith 2.5μmol/l,5μmol/l,10μmol/l and 20μmol/l MG132 for 24 hours,respectively. And the expression of p27 protein were detected byimmunocytochemistry. During the experiments the control group's cells were treated by the same concentration DMSO.Results (1) Hela cells became round, small, cell shrinkage,membrane blebbing and so on, after exposed to MG132.(2) After treatedwith MG-132, the growth of Hela cells were inhibited obviously. Thediffferences of the proliferative inhibition rates among the differentconcentration's MG132 groups were statistically significant(F=3569.301,P＜0.001), and the differences of the proliferative inhibitionrates for different time were also statistically significant(F=6155.339,P＜0.001). The effect of different concentrations anddifferent time by MG132 on cell growth was interactive(F=272.722,P＜0.001). (3) Moreover, quantification of the apoptosis effect by flowcytometric analysis showed that it was in a good correspondence with theloss in cell viability induced by MG132. Different concentration'sMG132 groups were statistically significant (F=1182.745,P＜0.001);Meanwhile, treated with 10μmol/1 MG132 for 24, 48 and 72 hours, theapoptotic rate of HeLa cells advanced obviously, and the differenceswere significant (F=357.090, P＜0.001). Cell cycle arrested at G2/Mphase. The difference with control group were significant (F=49.206,P=0.001). (4) In contrast to control group, The p27 protein expressionlevel obvious up-regulated in Mg132 group.(P＜0.05).Conclusions These observations suggested that the proteasomeinhibitor MG132 decreased cell growth and caused apoptosis of humancervical cacinoma cell line Hela cells in a dose-effect relationship. In addition, The apoptotic effect of MG132 in cervical cancer cells wereproposed to following by p27-overexpressing.