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Objective@#To study the effect of apoptosis-stimulating protein 2 of p53 (ASPP2) on the activation and apoptosis of hepatic stellate cells induced by transforming growth factor-β1 (TGF - β1), and to explore the role of autophagy in this process.@*Methods@#Mouse hepatic stellate cells were primarily isolated and cultured with green fluorescent protein (GFP) expressing empty vector adenovirus (Ad-GFP) and ASPP2 expressing adenovirus (Ad-ASPP2) for 12 h by transfection kit, and then treated with TGF-β1 (10ng/ml) for 24 h. The experiments were grouped as follows: control group: green fluorescent protein (GFP) expressing empty vector adeno (Ad-GFP); experimental group 1: transfected with Ad-GFP and added with TGF-β1; experimental group 2: transfected with Ad-ASPP2 and induced by TGF-β1. Western blot and quantitative fluorescence PCR were used to detect the expression of ASPP2, α-smooth muscle actin (SMA). At the same time, autophagy was determined by microtubule-associated protein 1 light chain 3-β (LC3). Autophagy and apoptosis of MHSc were observed by immunocytochemistry and RNA interference (RNAi). Multiple pairwise-comparisons between the mean of groups was performed by one-way ANOVA.@*Results@#The relative expression of α-SMA mRNA in mHSC of TGF-β1 + Ad-GFP group (16.83 ± 2.41) was significantly higher than Ad-GFP group (3.62 ± 0.56) (P < 0.05), while the relative expression of α-SMA mRNA (4.22 ± 0.48) in TGF-β1 + Ad-GFP group was significantly lower than TGF-β1 + Ad-GFP group (P < 0.05). The expression of α-SMA protein in each group was consistent with mRNA expression. The proportion of mHSC autophagy in TGF-β1 + Ad-GFP group (80%) was significantly higher than Ad-GFP group (35%); however, there was no statistically significant difference between the two groups. The proportion of mHSC autophagy in TGF-β1 + Ad-ASPP2 group was 42%, which was significantly lower than TGF-β1 + Ad-GFP group, but the apoptotic rate was significantly increased. Cells were simultaneously treated with autophagy inhibitors 3-MA and TGF-β1. The level of autophagy was not statistically significantly different from that of TGF-β1 + Ad-ASPP2 group, but the apoptotic rate was increased. In addition, the RNAi group added with ASPP2 had increased autophagy (LC3-II/LC3-I) than control RNAi group, and the rate of apoptosis was significantly decreased.@*Conclusion@#Overexpression of ASPP2 can alleviate the activation of mHSC and promote the apoptosis of HSC by inhibiting autophagy, so as to alleviate liver fibrosis.
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Objective@#To investigate the effect of Δ40p53, an alternative spliced isoform of p53 lacking the N-ter minus, on the pro-apoptotic function of p53.@*Methods@#The wild-type p53 was ectopically expressed in HCT116-p53-/- (endogenous Δ40p53 expression), HCT116-p53+ /+ (wild-type p53) and H1299 (p53-null) cells by adenoviral delivery, while Δ40p53 plasmid were transfected into these cells to overexpress Δ40p53. The levels of Δ40p53 and p53 mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR) and quantitative PCR. The expression of related proteins was deter mined by Western blotting. The interaction of p53 and Δ40p53 was observed by co-immunoprecipitation assay. Calcein-AM/propidium iodide (PI) staining and flow cytometry were used to detect the apoptotic rate of tested cells in each group.@*Results@#HCT116-p53-/- cells expressed endogenous Δ40p53 isoform. Neither transcription nor protein expression of wild-type p53 was interfered by the increased expression of Δ40p53. Full length p53 and Δ40p53 could bind to each other. Calcein-AM/PI staining showed that the apoptotic rates of H1299-Control, HCT116-p53-/- -Control, H1299+ p53, HCT116-p53-/-+ p53, H1299+ oxaliplatin (Oxa), HCT116-p53-/-+ Oxa, H1299+ p53+ Oxa and HCT116-p53-/-+ p53+ Oxa groups were (2.50±0.47)%, (2.40±0.32)%, (5.20±0.58)%, (4.10±0.18)%, (22.40±1.73)%, (19.30±1.11)%, (29.90±1.15)% and (39.30±2.26)%, respectively. It was statistically significant between H1299+ p53+ Oxa and HCT116-p53-/-+ p53+ Oxa groups (t=3.721, P=0.0205). Moreover, the apoptotic rates of H1299-Control, H1299+ Δ40p53, H1299+ p53, H1299+ p53+ Δ40p53, H1299+ Oxa, H1299+ Δ40p53+ Oxa, H1299+ p53+ Oxa and H1299+ p53+ Δ40p53+ Oxa groups were (2.60±0.35)%, (2.20±0.17)%, (4.80±0.49)%, (4.90±1.10)%, (20.30±1.10)%, (19.60±1.45)%, (27.90±1.39)%, (35.20±1.43)%, respectively. Furthermore, flow cytometry assay showed that the apoptotic rates of above cells were (2.70±0.32)%, (2.20±0.24)%, (4.60±0.48)%, (3.90±0.67)%, (19.30±1.11)%, (17.70±0.66)%, (28.30±2.76)% and (37.50±1.51)%, respectively. H1299+ p53+ Δ40p53+ Oxa cells showed higher cell apoptosis than H1299+ p53+ Oxa cells (t=2.930, P=0.042).@*Conclusion@#Δ40p53 isoform can bind to full-length p53, and enhance its pro-apoptotic function in tumor cells.
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Objective To study the effect of radiofrequency ablation (RFA) with sublethal temperature on the production of liver cancer stem cells (LCSCs) and on the expression of LCSCs-related transcriptional factors.Methods Mouse hepl-6 hepatoma cell line and clinical samples of patients with hepatocellular carcinoma (HCC) were used to test the expressions of LCSCs-related markers and transcriptional factors.Results Different temperatures were used to stimulate Hep1-6 cells,and it was proved that the temperature of 45℃ was a sublethal temperature that could not induce cell death.Flow cytometry testing showed that treatment with 45℃ could obviously increase CD13+,CD44+,CD90 and CD133+ Hep1-6 cells,suggesting that treatment with 45℃ could increase the production of above mentioned types of LCSCs in hep1-6 cells.Real-time quantitative polymerase chain reaction (RT-qPCR) assay indicated that the temperature of 45℃could cause significant increase in CD13,CD90 and CD133 mRNA.In all 5 HCC patients,CD13 mRNA in the recurrent HCC lesions was remarkably increased,CD133 mRNA was increased in 4 patients with recurrent HCC,and CD90 mRNA was increased in only one patient with recurrent HCC.Flow cytometry testing revealed that CD13+ LCSCs were strikingly increased in 4 recurrent HCC patients,while CD133+LCSC was increased in only one patient,suggesting that more close correlation existed between the increase of CD13+ LCSCs and the temperature of 45℃.RT-qPCR assay showed that in 4 recurrent HCC patients with increased CD13+ LCSC,the Sox2 and Stat2 among 13 LCSCs-related transcriptional factors were obviously increased.Flow cytometry testing showed that 45℃ treatment also increased the expression of Sox2 and Stat1 mRNA in Hep1-6 cells.Finally,Sox2 and Stat1 could be knockdown by siRNAs,indicating that both Sox2 and Stat1 transcriptional factors were involved in 45℃-induced production of CD13+ LCSCs in Hep1-6 cells.Conclusion In RFA therapy,the use of sublethal temperature of 45℃ can increase CD13+LCSCs,which is related to the promotion of Sox2 and Stat1 expression.The results of this study can be used for reference in the research of liver cancer recurrence.
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Objective To investigate the relationship between hepatitis B virus (HBV) infection and cytokeratin 18 (CK18) phosphorylation.Methods Liver tissues were taken from 21 chronic hepatitis B (CHB) patients by liver biopsy and 14 healthy controls were collected.Immunofluorescence double staining and Western blotting were used to detect CK18 pSer33 and CK18 pSer52 phosphorylation.HepG2 cell line was transfected with either 1.3 mer HBV vector or empty control vector.CK18 pSer33 or CK18 pSer52 phosphorylation were tested using immunofluorescence double staining and Western blotting.Total mRNA was extracted from the cells.The expressions of cell division cycle 2 (cdc2) and protein kinase Cε (pKCε) were analyzed by realtime polymerase chain reaction relative quantification.Statistical analyzee were performed by using two-independent samples t test.Results Compared to healthy controls,phosphorylation of CK18 pSer33 in HBsAg stained hepatocytes was significantly higher in CHB patients (t=6.618,P=0.000).However,no difference was found in phosphorylation of pSer52 (t=2.429,P=0.051).Phosphorylation of CK18 pSer33 and expression of cdc2 mRNA in HBV transfected HepG2 were significantly higher in empty vector transfected HepG2 (t=5.365,P=0.006),while no difference was found in phosphorylation of pSer52 and expression of pKCε mRNA (t=1.098,P=0.334).Conclusion HBV infection is significantly associated with phosphorylation of CK18 pSer33.
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Objective To investigate the central neurotoxicity induced by nucleoside analog reverse transcriptase inhibitors (NRTIs)-stavudine (D4T).Methods Mouse primary cortical neurons were cultured and treated with different concentrations of stavudine.Neuron apoptosis was analyzed by calcein/acetomethoxy/propidium iodide (AM/PI) staining. Morphological change of neuron was confirmed by immunofluorescence.Mitochondrial DNA copies which were usually evaluated through Cycloxygenase 2 (COX-2) and thymidine kinase2 (TK2) mRNA were determined by real-time quantitative polymerase chain reaction.Chi-square test,student t test and Wilcoxon nonparameter test were used to analyze the data.Results Neuronal apoptosis observed in 50 μmol/L D4T treatment group was more significant than that in 0μmol/L D4T treatment group and 25 μmol/L D4T treatment group (51.3％±12.4％ vs 24.9％±8.2％ and 26.5％±10.6％,respectively; x2 =7.25 and 6.93,respectively; both P＜0.01).The average neurite numbers of each neuron were 11.2±3.6 in 0μmol/L D4T treatment group,8.6±2.8 in 25 μmol/L D4T treatment group and 4.3±2.4 in 50 μmol/L D4T treatment group.The difference was statistically significant between 25 μmol/L D4T treatment group and 0 μmol/L D4T treatment group (t=4.06,P＜0.01) and between 50 μmol/L D4T treatment group and 25 μmol/L D4T treatment group (t =4.35,P＜ 0.01). Furthermore,the average lengths of neuritis were (319.9±100.2) μm in 0 μmol/L D4T treatment group,(298.3±83.9) μm in 25 μmol/L D4T treatment group and (258.4±82.2) μm in 50 μmol/L D4T treatment group.The difference was statistically significant between 25 μmol/L D4T treatment group and 0 μmol/L D4T treatment group (t=4.58,P＜0.01) and between 50 μmol/L D4T treatment group and 25 μmol/L D4T treatment group (t=4.65,P＜0.01).TK2 mRNA expression dramatically decreased along with the increasing D4T concentration.The fold changes were 0.34 in 25 μmol/L D4T treatment group and 0.08 in 50 μmol/L D4T treatment group. The difference was statistically significant between 25 μmol/L D4T treatment group and 0μmol/L D4T treatment group (Z=- 3.28,P＜0.01) and between 50 μmol/L D4T treatment group and 25 μmol/L D4T treatment group (Z=-4.25,P＜0.01).Compared with 0μmol/L D4T treatment group,the relative fold changes of COX-2 copies were 1.01 in 25 μmol/L D4T treatment group and 1.12 in 50 μmol/L D4T treatment group.The differences were not significant among the three groups (Z=0.98 and 1.24,respectively; both P＞0.05).Conclsion It suggests that short-term exposure to D4T may result in neuron apoptosis,neurite shrink and down-regulated expression of TK2,but the level of mitochondrial DNA copies keeps stable.