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Objective To investigate the relationship between the expression of ASPP2 mRNA and the methylation of ASPP2 gene in gastric cancer cells,to observe the inhibitory effect of 5-Aza-CdR on the growth of gastric cancer cells,to observe the effect of demethylation on the expression of ASPP2 mRNA and the methylation of ASPP2 gene in gastric cancer cells,and to explore the molecular mechanism of gastric cancer.Methods Real-time PCR was used to detect the expression of ASPP2 mRNA in two gastric cancer cells and normal gastric epithelial cells.BSP was used to detect the methylation of ASPP2 gene in two gastric cancer cells and normal gastric epithelial cells.CCK-8 was used to detect the growth inhibition rate of gastric cancer cells treated with 5-Aza-CdR of different concentrations,then they were used to detect expression of ASPP2 mRNA and the methylation of ASPP2 gene in gastric cancer cells again after the demethylation.Results ① The expression of ASPP2 mRNA in MKN-45 cells was significantly lower than that in GES-1 cells(P＜0.01).The expression of ASPP2 mRNA in MGC-803 cells was significantly lower than that in GES-1 cells (P＜0.01).There was no significant difference in MGC-803 cells and MKN-45 cells(P＞0.05).② The methylation rate of ASPP2 in MKN-45 cells was significantly higher than that in GES-1 cells (P＜0.01).The methylation rate of ASPP2 in MGC-803 cells was not significantly different from that in GES-1 cells (P＞0.05).The methylation rate of ASPP2 in MKN-45 cells was significantly higher than that in MGC-803 cells (P＜0.01).③ At the same time,the growth inhibition rate of each 5-Aza-CdR concentration group increased as the drug concentration depended.4.The expression of ASPP2 mRNA in MKN-45 cells was significantly higher than that before treatment (P＜0.01),the expression of ASPP2 mRNA in MGC-803 cells was not significantly different from that before treatment(P＞0.05).The methylation rate of ASPP2 in MKN-45 cells was significantly lower than that before treatment (P＜0.01).The methylation rate of ASPP2 in MGC-803 cells was not significantly different from that before treatment (P＞0.05).Conclusion ① Abnormal hypermethylation of ASPP2 gene in MKN-45 cells may be a molecular mechanism of decreased ASPP2 mRNA expression.② 5-Aza-CdR can inhibit the growth of MKN-45 and MGC-803 cells,and it can enhance the expression of ASPP2 mRNA in MKN-45 cells.Reversal of methylation in the promoter region of ASPP2 gene is the possible mechanism.③ Abnormal hypermethylation of the promoter region of ASPP2 gene may lead to silencing of mRNA expression that may be associated with gastric cancer.
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Objective To study the expression of ASPP2 and P16INK4a in esophageal carcinoma and their relationship to the apoptosis and related clinicopathological characteristics. Methods Immunohistochemistry S-P method was used to examine the expression of ASPP2 and P16INK4a in the pathological specimens of 112 esophageal carcinoma cases and 31 cases of normal esophageal mucosa. TUNEL was also employed to detect the rate of apopto-sis in 37 esophageal carcinoma cases and 12 cases of normal esophageal mucosa. Results The difference between the expression of ASPP2 and P16INK4a in esophageal carcinoma and normal esophageal mucosa was statistically signif-icant(P < 0.05). Their abnormal expressions were all related to lymph node metastasis and differentiation degree (P < 0.05). The difference between the positive rate of apoptosis in esophageal carcinoma and normal esophageal mucosa was statistically significant(P < 0.05). The abnormal expression of ASPP2 and P16INK4a was all related to apoptosis in esophageal carcinoma. Conclusions The different expression of ASPP2 and P16INK4a may cooperatively play a role in differentiation degree ,lymph nodes metastasis and apoptosis in esophageal carcinoma. Co-examina-tion of them may be useful for the diagnosis and guiding the clinical treatment in esophageal carcinoma.
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Objective To study the expression of ASPP2 and P16INK4a in esophageal carcinoma and their relationship to the apoptosis and related clinicopathological characteristics. Methods Immunohistochemistry S-P method was used to examine the expression of ASPP2 and P16INK4a in the pathological specimens of 112 esophageal carcinoma cases and 31 cases of normal esophageal mucosa. TUNEL was also employed to detect the rate of apopto-sis in 37 esophageal carcinoma cases and 12 cases of normal esophageal mucosa. Results The difference between the expression of ASPP2 and P16INK4a in esophageal carcinoma and normal esophageal mucosa was statistically signif-icant(P < 0.05). Their abnormal expressions were all related to lymph node metastasis and differentiation degree (P < 0.05). The difference between the positive rate of apoptosis in esophageal carcinoma and normal esophageal mucosa was statistically significant(P < 0.05). The abnormal expression of ASPP2 and P16INK4a was all related to apoptosis in esophageal carcinoma. Conclusions The different expression of ASPP2 and P16INK4a may cooperatively play a role in differentiation degree ,lymph nodes metastasis and apoptosis in esophageal carcinoma. Co-examina-tion of them may be useful for the diagnosis and guiding the clinical treatment in esophageal carcinoma.
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Aim Toanalyzethekeyqualityandestablishmeth-ods for essential quality control of human recombinant ASPP2 adenovirus.Methods TheviralstructuralgeneofE2Bandtar-get gene of ASPP2 were identified by PCR;The number of virus particles was measured by UV-SDS methods;Infectious titer was determined by TCID50 assay;Target protein of ASPP2 was ob-served by Western blot assay;The biological effects of recombi-nant adenovirus on liver cancer cells were evaluated by MTT as-say;A549 cells were used to check replication of the competent adenovirus(RCA)by the observation of the cytopathic effect. Results PCRanalysisofE2BandASPP2wasinconsistent with theoretical values;Particle numbers of virus were 5. 6 × 1012 VP/mL,infectious titer was 2 ×1011 IU/mL and specific activity was 3. 5%;ASPP2 protein expression could be detected when cells were infected with virus for 24 h;Growth inhibition of liver cancer cells could be found by adding recombinant ASPP 2 adenovirus;The level of RCA was less than 1 RCA/3. 0 ×1010 VP,in line with the standards of China Food and Drug Adminis-tration(SFDA).Conclusion Thequalitycontrolmethodswere established aiming at key characters of human recombinant AS-PP2 adenovirus,which may provide foundations for its quality standard and future applications.
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Objective To study the effects of apoptosis-stimulating protein of ρ53-2 (ASPP2) gene on hepatocellular carcinoma (HCC) cell proliferation and apoptosis under starvation and the related mechanism. Methods Lentivirus encoding shRNA against ASPP2 was constructedto knockdown ASPP2 expression in hepatoma cell HepG2. Cell proliferation and apoptosis were observed by transmission electron microscopy, MTS analysis, flow cytometry analysis and morphologic changes. The influence of silencing ASPP2 gene on the proliferation and apoptosis under amino acid-starvation and serum-deprivation culture was observed; autophagy inhibitor 3-methyladenine (3-MA) was added in the experiment so as to detect the involvement of autophagy in the changes induced by ASPP2 down-regulation. Results Transmission electron microscopy showed cytoplasmic accumulation of autophagosomes when ASPP2 was knocked down under amino acid-starvation and serum- deprivation (P<0. 05), with increased GFP-LC3 dots (P<0. 05). MTS analysis showed that silence of ASPP2 gene greatly enhanced the proliferation of HepG2 cells (P<0. 05), which could be inhibited by addition of 3-MA (P<0. 05). Microscope observation showed that silence of ASPP2 gene promoted the anti-apoptotic ability of HepG2 cells, which was reversed by treatment with 3-MA. Early sign of apoptosis was observed in shASPP2 + 3-MA group. Annexin V_PI double staining showed that ASPP2 silence decreased the apoptotic rate ofHepG2 cells from (38±5)% to(15±4)% (P<0. 05), and 3-MA treatment increased it to (36 ±3)% (P<0. 05). Conclusion Down-regulation of ASPP2 expression may facilitate the survival and proliferation of HCC cells through activating autophagy under starvation.