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Objective:To study the regulatory effect and mechanism of MDM2/p53 pathway on apoptosis in multiple myeloma (MM). Methods: RPMI8226 cells were cultured in vitro and divided into Nutlin-3a group, control group and blank group. CCK-8 method was used to detect the cell inhibition rate, Western blot was used to detect the expression of apoptosis-related protein, and flow cytometry was used to detect the apoptosis in the two groups. Results: Compared with that in control group, the inhibition rate of cells in the experimental group increased significantly at 24 h, 48 h and 72 h (P<0.05). Compared with those in the control group, the expression levels of MDM2 and Bcl-2 in the experimental group decreased significantly (P<0.05), while the expression level of p53 increased significantly (P<0.05). The apoptosis rate was significantly higher in the experimental group than in the control group at 24 h, 48 h and 72 h (38.42%, 82.26% and 82.74% vs. 4.80%, 8.06% and 14.69%). Conclusion: The degradation trans-activation pathway between MDM2 and p53 affects the expression of Bcl-2, inhibits the proliferation of MM cells, and promotes the apoptosis of MM cells.
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Objective:To evaluate the effect of Nutlin-3,a MDM2 antagonist,on the pyroptosis in SMMC-7721 cells.Methods: The expression of actived caspase-1(p20) and IL-1β was detected using Western blot analysis.Pyroptosis was investigated by a standard lactate dehydrogenase release assay(LDH).IL-1β content in the cell culture supernatant was quantified by ELISA.Results: Nutlin-3 up-regulated the expression level of actived caspase-1 and IL-1β in SMMC-7721 cells.Meanwhile,Nutlin-3 increased significantly the content of LDH and IL-1β in the cell culture supernatant(P<0.05).Conclusion: Nutlin-3 activated pro-caspase-1,promoted pyroptosis and IL-1β release in SMMC-7721 cells.
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Objective To estimate the effect of a cis-imidazoline derivative,nutlin-3,on the biological behavior of A375 human melanoma cells,and to investigate its mechanism.Methods Cultured A375 cells were divided into several test groups treated with nutlin-3 at different concentrations (2.5,5,10 μmol/L) for 24,48 and 72 hours,and a control group treated with dimethyl sulfoxide (DMSO) only.Then,methyl thiazolyl tetrazolium (MTT) assay was performed to evaluate cellular proliferative activity,Western blot to measure the expression of p53 protein,flow cytometry to estimate cell cycle phase distribution and apoptosis rate,and Transwell assay to evaluate migratory activity,of A375 cells.Statistical analysis was carried out by repeated-measures analysis of variance (ANOVA).Results After treatment with nutlin-3 of 2.5,5 and 10 μmol/L for 24,48 and 72 hours,significant differences were observed among different time points at each concentration and among different concentrations at the same time point in proliferation inhibition rate (F =67.43,135.58,respectively,both P ＜ 0.01),p53 protein expression level (F =1255.00,9196.00,respectively,both P ＜ 0.01),percentage of cells at G2 phase (F =831.38,267.99,respectively,both P ＜ 0.01),apoptosis rate (F =809.45,723.83,respectively,both P ＜ 0.01),migration inhibition rate (F =1100.00,1667.00,respectively,both P ＜ 0.01).The influence of nutlin-3 on cellular proliferative activity increased with the increase in its concentration,and that on percentage of cells at G2 phase,apoptosis rate and migratory activity increased with the increase in its concentration and treatment duration.There was a significant interaction between the treatment duration and concentration of nutlin-3 for p53 protein expression level in (F =826.79,P ＜ 0.01),percentage of cells at G2 phase in (F =21.602,P ＜ 0.01),apoptosis rate in (F =44.48,P ＜ 0.01),migratory activity of (F =313.09,P ＜ 0.01),and cellular proliferative activity of (F =26.95,P ＜ 0.01),A375 cells.Conclusion Nutlin-3 may inhibit the proliferation and migration of,but promote cell cycle arrest and apoptosis in,A375 cells,through accumulation of p53 protein.
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Objective To study the effects of UVR or H2O2 on the expression of p53 in human melanocytes,and that of nutlin-3 and PFT-α on the DNA oxidative damage,and to investigate the role of p53 in the antioxidative stress.Methods The effect of UVR,H2O2,nutlin-3 and PFT-α on the expression of p53 of human melanocytes was detected by Western blot analysis,and that of nutlin-3 and PFT-α on UVR or H2O2 DNA damage assessed by single cell electrophoresis (comet assay).Determination of the effect of nutlin-3 on H2O2 DNA damage was detected by γ-H2AX immunofluorescence.Results UVR and H2O2 could induce p53 protein expression,accompanied by increased phosphorylation of p53 on serine 15 residue,and nutlin-3 and PFT-α could induce and inhibit p53 protein in human melanocytes respectively; nutlin-3 decreased the tail moment of DNA oxidative damage of UVR or H2O2 in human melanocytes,but PFT-α increased the tail moment of DNA oxidative damage of UVR or H2O2 in human melanocytes,and there were significant differences among the control and exposed groups; nutlin-3 decreased expression of γ-H2AX.Conclusions p53 plays a very important role in the antioxidative stress in melanocyte exposed to UV or H2O2.