Correlation between expression of gastrin, somatostatin and cell apoptosis regulation gene bcl-2/bax in large intestine carcinoma

AIM: To explore the correlation between expression of somatostatin (SS), gastrin (GAS) and cell apoptosis regulation gene bcl-2/bax in large intestine carcinoma.METHODS: Sixty-two large intestine cancer tissue samples were randomly and retrospectively selected from patients with large intestine carcinoma. Immunohistochemical staining for bcl-2, bax, GAS, SS was performed according to the standard streptavidin-biotin-peroxidase (S-P) method.According to the semi-quantitative integral evaluation, SS and GAS were divided into three groups as follows. Scores1-3 were defined as the low expression group, 4-8 as the intermediate expression group, 9-16 as the high expression group. Bax and bcl-2 protein expressions in different GAS and SS expression groups of large intestine carcinoma were assessed.RESULTS: The positive expression rate of bax had a prominent difference between SS and GAS high, intermediate and low expression groups (P＜0.05, x2ss = 9.246; P＜0.05,x2GAS = 6.981). The positive expression rate of bax in SS high (80.0%, 8/10) and intermediate (76.5%, 13/17)expression groups was higher than that in low expression group (40.0%, 14/35) (P＜0.05, x2high vs low = 5.242; P＜0.05,x2middle vs low = 6.097). The positive expression rate of bax in GAS high expression group (27.3%, 3/8) was lower than that in low expression group (69.4%, 25/36) (P＜0.05,x2 = 4.594). However, bax expression in GAS intermediate expression group (46.7%, 7/15) was lower than that in low expression group, but not statistically significant. The positive expression rate of bcl-2 had a prominent difference between SS and GAS high, intermediate and low expression groups (P＜0.05, x2ss = 7.178; P＜0.05, x2GAS = 13.831). The positive expression rate of bcl-2 in GAS high (90.9%, 10/11)and intermediate (86.7%, 13/15) expression groups was higher than that in low expression group (44.4%, 16/36)(P＜0.05,x2high vs low = 5.600; P＜0.05, x2 middle vs low = 7.695).However, the positive expression rate of bcl-2 in SS high (40.0%, 4/10) and intermediate (47.1%, 8/9) expression groups was lower than that in low expression group (77.1%, 27/35)(P＜0.05, x2 high vs low = 4.710; P＜0.05, x2 middle vs low = 4.706).There was a significant positive correlation between the integral ratio of GAS to SS and the integral of bcl-2 (P＜0.01,r=0.340). However, there was a negative correlation between the integral ratio of GAS to the SS and bax the integral of (P＜0.05, r = -0.299).CONCLUSION: The regulation and control of gastrin,somatostatin in cell apoptosis of large intestine carcinoma may be directly related to the abnormal expression of bcl-2, bax.

Expression of Bcl-2 inhibited Fas-mediated apoptosis in human hepatocellular carcinoma BEL-7404 cells

Apoptosis plays an important role in embryonic development, tissue remodeling, immune regulation and tumor regression. Two groups of molecules (Bcl-2 family and "Death factor" family) are involved in regulating apoptosis. In order to know about the effect of Bcl-2 on apoptosis induced by Fas, a typical member of "Death factor" family, the transfection experiments with expression vectors pcDNA3-fl and pcDNA3-bcl-2 were performed in BEL-7404 cells, a human hepatocellular carcinoma cell line which expresses endogenous Fas, but not FasL and Bcl-2. The data showed that the expression of FasL in pcDNA3-fl transfected hepatoma cells obviously induced the apoptosis of the cells. However, the overexpression of Bcl-2 in pcDNA3-bcl-2 transfected 7404/b-16 cells counteracted pcDNA3-fl transient transfection mediated apoptosis. Further study by cotransfection experiments indicated that Bid but not Bax (both were pro-apoptotic proteins of Bcl-2 family) blocked the inhibitory effect of Bcl-2 on Fas-mediated apoptosis. These results suggested that Fas-mediated apoptosis in human hepatoma cells is possibly regulated by Bcl-2 family proteins via mitochondria pathway.

H pylori (CagA) and Epstein-Barr virus infection in gastric carcinomas:Correlation with p53 mutation and c-Myc,Bcl-2 and Bax expression

AIM: To investigate the interrelationship between H pylori and Epstein-Barr virus (EBV) infection in the gastric carcinogenesis having in focus the p53 mutation and the c-Myc, Bcl-2 and Bax expression. METHODS: seventy-one gastric carcinoma tissues were assessed by polymerase chain reaction (PCR) for H pylori and in situ hybridization for EBV. c-Myc, Bcl-2 and Bax expression were detected by immunohistochemistry and single-stranded conformational polymorphism (SSCP) for p53 mutation. RESULTS: The positivity rates for H pylori and EBV were 94.4% and 8.45%, respectively. The majority of the cases displayed only the H pylori presence. All EBV positive cases were also H pylori positive. None infectious agent was observed in 5.55% of the cases. The intestinal type tumor was more frequent in the co-infected and non-infected groups. The female predominated in the non-infected group showing statistical significance (70.4% vs 29.6%, P=0.039). The Bcl-2 was only detected in the group exclusively infected by H pylori. However, c-Myc and Bax were detected in the three groups but with a low frequency in the co-infected group. Mutation of p53 was present in all groups, with the highest frequencies in the H pylori positive groups. CONCLUSION: The frequency of H pylori infection in gastric carcinomas was high. The presented data indicated that gastric carcinogenesis has different pathways depending of the presence of the two investigated infectious agents, suggesting a possible involvement of H pylori with apoptotic process. The low expression of c-Myc and Bax in the EBV-positive groups suggests that EBV may inhibit the expression of these proteins. Nevertheless, p53 mutation shows to be a relevant alteration, independent of both infectious agents.

THE EXPRESSION OF BCL-2 AND BAX PROTEINS IN GASTRIC CARCINOMA AND PRECANCEROUS LESIONS

Objective To investigate the variance of expression of bcl-2 and bax genes in the genesis or gastric carcinoma as well as their relationship. Methods Thirty-five cases of early-stage gastric carcinoma and Twenty-four cases ot chronic atrophic gastritis were studied by immunohistochemical method. Results There were no statistical differences of bcl-2 expression levels between gastric carcinoma and atypical hyperplasia or paracancerous intestinal- epithelial metaplasia(IEM) (P>0.05).There were statistical differences of bcl-2 expression between normal epithe- lial tissues (or non-cancerous IEM) and the other three groups(P<0.05), but no statistical difference between the normal epithelial and the non-cancerous IEM group was observed(P>0.05). The expressions or bax protein were found in the normal epithelial and the other groups in varying degrees,but there were no statistical differences be- tween either two of the groups (P>0.05). The bcl-2/bax ratio was higher in early-stage gastric carcinoma,atypical hy- perplasia and paracancerous intestinal-metaplasia than in the non-cancerous intestinal-metaplasia (P<0.05) and nor- mal epithelial tissues(P<0.01). Conclusion The abnormal expression of bcl-2 protein and bax protein,especially the increased bcl-2/bax ratio, probably play an important role in the course of carcinogenesis or gastric carcinoma.

Effect of Bcl-2 and Bax on survival of side population cells from hepatocellular carcinoma cells

AIM： To understand the role and significance of side population （SP） cells from hepatocellular carcinoma （HCC） in hepatocarcinogenesis, development, relapse and metastasis, we simulated the denutrition conditions that cancer cells experience in clinical therapy, observed the different anti-apoptosis ability of SP cells and non-SP cells under such conditions, and established the possible effects of P53, Bcl-2 and Bax on survival of SP cells. METHODS： We used flow cytometry to analyze and sort the SP and non-SP cells in established HCC lines MHCC97 and hHCC. We evaluated cell proliferation by methyl thiazolyl tetrazolium （MTT） assay and investigated the expression of p53, bcl-2 and bax genes during denutrition, by RT-PCR and immunofluorescence staining. RESULTS： The percentage of SP cells in the two established HCC lines was 0.25% and 0.5%, respectively. SP cells had greater anti-apoptosis and proliferation ability than non-SP cells. Expression of Bcl-2 and Bax in SP and non-SP cells differed during denutrition. The former was up-regulated in SP cells, and the latter was up-regulated in non-SP cells. CONCLUSION： It may be that different upstream molecules acted and led to different expression levels of Bcl-2 and Bax in these two cell lines. There was a direct relationship between up-regulation of Bcl-2 and down-regulation of Bax and higher anti-apoptosis ability in SP cells. It may be that the existence and activity of SP cells are partly responsible for some of the clinical phenomena which are seen in HCC, such as relapse or metastasis. Further research on SP cells may have potential applications in the field of anticancer therapy.

Induction of apoptosis of human gastric carcinoma SGC-7901 cell line by 5,7-dihydroxy-8-nitrochrysin in vitro

AIM： To investigate the effect of 5, 7-dihydroxy-8- nitrochrysin （NOChR） on apoptosis of human gastric carcinoma SGC-7901 cell line.METHODS： SGC-7901 cells were cultured in vitro and the inhibitory effect of NOChR on proliferation of SGC-7901 cells was measured by using an Ml-r assay. NOChR-induced apoptosis rate of SGC-7901 cells was detected using flow cytometry （FCM） with PI staining. DNA ladder bands were observed by DNA agarose gel electrophoresis. The influence of NOChR on the proxisome proliferator-activated receptor-γ （PPARγ）, Bcl-2 and Bax protein expression of SGC-7901 cells was analyzed by Western blot.RESULTS： MIF assay showed that NOChR markedly inhibited proliferation of SGC-7901 cells in a dose- dependent manner, and when ICso was 4.14 μmol/L, the potency of NOChR was 10 times than that of lead compound, chrysin （ChR, IC50 was 40.56 μmol/L）, and was similar to 5-fluorouracil （5-FU, IC50 was 4.51 μmol/L）. FCM with propidium iodide （PI） staining demonstrated that the apoptosis rates of SGC-7901 cells treated with 1.25, 5.00 and 20.00 μmol/L NOChR for 48 h were 9.8% 4- 0.2%, 36.8% 4- 1.9% and 45.5% 4- 3.5%, respectively, and were significantly higher when treated with 5.00 and 20.00 μmol/L NOChR than that with 20.00 μmol/L ChR （12.9% 4- 1.5%）. DNA agarose gel electrophoresis showed that treatment of SGC-7901 cells with 20.00 μmol/L NOChR for 48 h resulted in typical DNA ladder bands of DNA of SGC-7901 cells, which could be eliminated by treating with 10.00 μmol/L GW9662, a blocker of PPARy. Western blot analysis revealed that after 24 h of treatment with 20.00 μmol/L NOChR, PPARgamma and Bax protein expression of SGC-7901 cells increased but Bcl-2 expression decreased; however, pre-incubation with 10.00 μmol/L GW9662 could efficiently antagonize and weaken the regulatory effect of 20.00 μmol/L NOChR on Bax and Bcl-2 protein expression of SGC-7901 cells. CONCLUSION： NOChR induces apoptosis of SGO7901 cell lines by activating PPARy and decreasing ratio of Bcl-2 to Bax.

Relationship between Epstein-Barr virus-encoded proteins with cell proliferation,apoptosis,and apoptosis-related proteins in gastric carcinoma

AIM: To investigate the interrelationship between Epstein-Barr virus (EBV)-encoded proteins and cell proliferation, apoptosis and apoptosis-related proteins in gastric carcinoma, and to explore their role in gastric carcinogenesis. METHODS: Tissues from 13 cases of EBV-associated gastric carcinoma (EBVaGC) and 45 cases of matched EBV-negative gastric carcinoma (EBVnGC) were collected, and then subjected to analysis for apoptotic index (AI) using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end-labeling (TUNEL) assay. Nuclear cell proliferation-associated antigen ki-67 index (KI), bcl-2, and p53 expression were examined by immunohistochemistry.p53 mutation in exons 5-8 of 13 EBVaGC cases was determined by single-strand conformation polymorphism (SSCP) and DNA sequencing.RT-PCR and Southern hybridization were used to detect the expression of nuclear antigens (EBNAs) 1 and 2, latent membrane protein (IMP) 1, immediately early gene BZLF1 and early genes BARF1 and BHRF1 in 13 EBVaGC cases. RESULTS: The percentage of AI, KI and p53 overexpression was significantly lower in the EBVaGC group than in the EBVnGC group. However, bcl-2 expression did not show significant difference between the two groups. p53 gene mutations were not found in 13 EBVaGCs. Transcripts of EBNA1 were detected in all 13 EBVaGCs, while both EBNA2 and LMP1 mRNA were not detected. Six of the thirteen cases exhibited BZLF1 transcripts and two exhibited BHRF1 transcripts. BARF1 mRNA was detected in six cases. CONCLUSION: Lower AI and KI may reflect a low biological activity in EBVaGC. EBV infection is associated with p53 abnormal expression but not bcl-2 protein in EBVaGC. BZLF1,BARF1,and BHRF1 may play important roles in inhibiting cell apoptosis and tumorigenesis of EBVaGC through different pathways.

Apoptosis of human gastric carcinoma cells induced by Euphorbia esula latex

AIM: To investigate the effect of Euphorbia esula(E. esula) extract in inhibiting proliferation and inducing apoptosis in SGC-7901 cells.METHODS: E. esula extract at different concentrations was used to inhibit proliferation and induce apoptosis of human gastric carcinoma SGC-7901 cells. Inhibition of proliferation was detected with thiazolyl blue assay, and apoptosis was detected with fluorescence microscopy, transmission electron microscopy, and flow cytometry. The mechanisms were studied by measurement of caspase-3 and caspase-8 activities and Bax and Bcl2 m RNA expression.RESULTS: The thiazolyl blue assay showed that SGC-7901 cell viability and proliferation were inhibited significantly by E. esula extract in a timeand concentration-dependent manner. Fluorescence microscopy revealed that the cell nuclei showed the characteristic changes of apoptosis, such as uneven staining and chromatin marginalization. Some key features of apoptosis were also observed undertransmission electron microscopy, which included cellular shrinkage and the foaming or bubbling phenomenon. When the cells were analyzed by flow cytometry, a sub-G1 peak could be seen clearly. Spectrophotometric assay of caspase-3 and caspase-8 activities in the treated cells showed an approximately two-fold increase. Reverse transcriptase polymerase chain reaction showed that Bax m RNA expression was upregulated, while Bcl2 m RNA expression was downregulated.CONCLUSION: E. esula extract inhibited proliferation and induced apoptosis in SGC-7901 cells, in a caspasedependent manner, involving upregulation of Bax and downregulation of Bcl2.

The Effect of Nimesulide on the Expression of NF-κB,Bcl-2 and Bax in the Human Gastric Cancer SGC-7901 Cell Line

OBJECTIVE To investigate whether nimesulide can suppress tumor growth and induce apoptosis in SGC-7901 gastric cancer cells and to explore the molecular mechanism involved. METHODS SGC-7901 cells were cultured in RPMI 1640 medium containing different concentrations of nimesulide （0,12.5, 50, 100, 200, 400 μmol/L）. The MTT assay, morphological observation, electron microscopy （EM）, immunohistochemical analysis and Western blot analysis were employed to investigate the effects of nimesulide on the SGC-7901 cells and to explore possible related molecular mechanisms. RESULTS Nimesulide inhibited the growth of SGC-7901 cells and elicited typical apoptotic morphologic changes. Nimesulide also decreased NF-κB and Bcl-2 expression, but increased the level of the Bax protein. The positive rate of Bcl-2 protein expression at 0, 50, 100 and 200 μmol/L of nimesulide was 58.3±14.0%, 50.2±9.9%, 32.8±5.0% and 22.7±5.5% respectively based on immunohistochemical staining. The positive rate of Bax protein expression was 22.0±5.7%, 29.2±6.5%, 42.7±5.9% and 74.5±9.1% and the NF-κB expression was 74.2±10.9%, 61.8±7.6%, 36.7±10.9% and 17.5±12.3%, Significant differences were found between so μmol/L and 100 μmol/L and 200μmol/L. Western blot analysis also showed that the expression of NF-κB was decreased. CONCLUSION Nimesulide suppresses tumor growth and induces apoptosis by inhibiting NF-κB expression, which may be related to the overexpression of Bax relative to Bcl-2 expression.

细胞凋亡相关基因bcl-2与bax在胃癌组织中表达探讨

目的:探讨凋亡相关基因bcl-2和bax在人胃癌组织中蛋白的表达情况及其与胃癌的各种临床病理特征和预后的关系。方法:用免疫组织化学SABC法检测经手术治疗的72例胃癌患者的病理标本,用TUNEL法检测其中的细胞凋亡情况。同时检测13例正常胃组织作为对照。结果:bcl-2蛋白在胃癌组织中的阳性表达率为36.11%,bax为52.78%,两者与正常胃组织比较差异均有统计学意义(P<0.05和<0.01)。结论:bcl-2和bax蛋白的表达与胃癌的lauren分型、分化程度及淋巴结转移相关,并通过对细胞凋亡的调控参与了胃癌的发生、发展,和预后密切相关。

左金方通过上调Bax/Bcl-2下调MMP诱导人胃癌细胞SGC-7901的凋亡

目的研究左金方诱导人胃癌细胞SGC-7901凋亡的作用机制。方法采用MTT比色法观察左金方对SGC-7901的生长抑制情况;流式细胞仪PI单染亚二倍体峰分析细胞凋亡率;Hoechst 33258染色观察细胞形态学变化;Western blot方法检测Bcl-2、Bax蛋白表达以及JC-1试剂盒测定细胞膜电位。结果左金方能抑制细胞活性,与时间-剂量呈依赖关系。0.1、0.5和1.0 mg·m L-1左金方作用于SGC-7901细胞48 h后,细胞凋亡率分别为(11.60±1.24)%、(21.80±0.28)%、(36.40±1.59)%,与对照组(2.66±1.33)%比较差异均有统计学意义(P<0.01);Hochest染色细胞出现核固缩状和颗粒状荧光等典型的凋亡学特征;左金方可降低SGC-7901细胞Bcl-2基因表达和增加Bax基因表达;左金方作用SGC-790l 4 h后,可以明显引起细胞MMP的下降;1.0 mg·m L-1左金方组的作用尤其明显。结论左金方通过上调Bax/Bcl-2比率,下调MMP诱导了人胃癌细胞SGC-7901的凋亡。

Bcl-2、Bax在胃癌及胃癌前病变中的表达与细胞凋亡的关系

目的探讨胃癌及胃癌前病变组织中Bcl-2、Bax的表达情况及其与细胞凋亡的相互关系。方法采用免疫组织化学SP法分别检测10例正常胃黏膜、60例慢性萎缩性胃炎伴肠化生、30例异型增生、50例胃癌中Bcl-2、Bax蛋白的表达情况,采用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记技术(TUNEL法)检测组织切片中细胞凋亡的情况。结果慢性萎缩性胃炎伴肠化生、异型增生、胃癌中Bcl-2蛋白表达阳性率分别为31.7%,43.3%,62.0%,均显著高于正常胃黏膜(P<0.01)。慢性萎缩性胃炎伴肠化生、异型增生中Bax蛋白阳性率分别为55.0%,30.0%,其阳性率均显著高于胃癌(P<0.01,P<0.05)。Bcl-2蛋白表达阳性慢性萎缩性胃炎伴肠化生、异型增生和胃癌中凋亡细胞指数(AI)显著低于Bcl-2蛋白阴性组(P<0.05),Bcl-2蛋白表达阳性率与AI值呈负相关。Bax蛋白表达阳性慢性萎缩性胃炎伴肠化生、异型增生和胃癌中AI显著高于Bax蛋白阴性组(P<0.05),Bax蛋白表达阳性率与AI值呈正相关。结论胃黏膜癌变过程中,AI、凋亡调控基因Bcl-2和Bax的比值逐渐增加,说明它们在胃癌演变过程中可能起重要作用。

Niuhuang(Bovis Calculus)-Shexiang(Moschus)combination induces apoptosis and inhibits proliferation in hepatocellular carcinoma via PI3K/AKT/mTOR pathway

Objective To investigate the effects of Niuhuang(Bovis Calculus,BC)and Shexiang(Moschus)(BC-Moschus)on human hepatocellular carcinoma(HCC)cells SMMC-7721 and a nude mouse model of subcutaneous xenografts,and to explore its anti-HCC mechanism.Methods The BC-Moschus combination was applied to two liver cancer models in vivo and in vitro.SMMC-7721 was divided into the BC-Moschus group and the control group,and different doses(rude drug dosage 0.625,1.25,2.5,and 5 mg/m L)of BC-Moschus extract were used for the intervention.The proliferation ability of HCC cells was detected using the Cell Counting Kit-8(CCK-8)assay,and the migration ability was detected by a wound healing assay.A subcutaneous xenograft model was prepared using nude mice with human HCC.Specific pathogen-free-grade BALB/c nude mice(5-week-old)were randomly divided into the following groups(n=6 per group):control(0.9%physiological saline 0.2 m L/d),BC-Moschus[BC 45.5 mg/(kg·d)+Moschus 13 mg/(kg·d)],and cisplatin(DDP,intraperitoneal injection5 mg/kg per week)groups.All groups were administered for 14 d.The volume and mass of the subcutaneous xenografts in nude mice were observed.The expression levels of phosphatidylinositol-3 kinase/protein kinase B/mammalian target of rapamycin(PI3K/AKT/mTOR)pathway,apoptosis-associated factor p70 S6 Kinase(S6K),Bax,Bcl-2,caspase-3,and caspase-9 in nude mice subcutaneous xenografts were measured by real-time quantitative PCR(RT-qPCR)and Western blot.Terminal Deoxynucleotidy Transferase-Mediated d UTP NickEnd Labeling(TUNEL)was used for quantitative analysis of apoptotic cells.Results The CCK-8 assay demonstrated that the BC-Moschus combination inhibited HCC cell proliferation in a superior manner to the use of BC and Moschus alone,and the inhibition effect was dose-and time-dependent(P<0.01).The wound healing assay showed that the BC-Moschus combination inhibited HCC cell migration(P<0.01).In the subcutaneous xenograft model of nude mice with human HCC,we found that the tumor volume and weight of the BC-Moschus group were lower than those of the control group(P<0.01).The levels of the PI3K/AKT/m TOR signaling pathway and S6K protein in the BC-Moschus and DDP groups were significantly decreased(P<0.01).The expression level of the anti-apoptotic gene Bcl-2 was downregulated(P<0.05),and the expression of the pro-apoptotic gene Baxand apoptosis-related factors caspase-3 and caspase-9 were significantly upregulated(P<0.01).The TUNEL assays further confirmed that the combination of the BC-Moschuas could promote HCC(P<0.01).Conclusion The BC-Moschus combination inhibited the proliferation and migration ability of HCC cells SMMC-7721 and effectively inhibited the growth of subcutaneous xenografts in nude mice.The mechanism may be closely related to the downregulation of the PI3K/AKT/mTOR pathway,regulation of apoptosis-related protein caspase-3,caspase-9,Bcl-2,and Bax expression,and promotion of apoptosis.

The Regulating Effect of CCK and Gastrin on Apoptosis of Bile Duct Carcinoma Cells

Objective Probe into the influence and the mechanisms of CCK and gastrin on the apoptosis of bile duct carcinoma cells. Methods By taking beauvericin as the revulsant to the apoptosis of bile duct carcinoma cells, the influence of CCK and gastrin on the apoptosis of bile duct carcinoma cells was investigated by using the techniques such as TUNEL fluorescent staining, stream mode cell detecting instrument and reverse bcl-2 oligonucleotide. Techniques of immunohistochemistry, in situ hybridization, flow cytometry (FCM) , RT-PCR were used to study the roles of apoptosis-related genes bcl-2 and baxResults After beauvericin 40 uM worked for 12 h, the survival rate of QBC939 bile duct carcinoma cells was decreased by 35% ?40% . About 80% of the bile duct carcinoma cells showed various degrees of apoptosis. CCK and gastrin could upregulate the threshold value of the apoptosis of bile duct carcinoma cells, which could be inhibited by L60, L18 and reverse bcl-2 oligonucleotide. In terms of both transcription and translating levels, CCK and gastrin could obviously promote the genetic expression of bcl-2, but had no influence on the genetic expression of bax. Addition of CCK-A receptor or CCK-B/gastr in receptor antagonist could remarkably inhibit the expression of bcl-2 boosted by gastrin-17 and CCK-8S.Conclusion CCK and gastrin inhibited the apoptosis of bile duct carcinoma cells through upregulating the genetic expression of bcl-2. Theoretically, this research has expanded our understanding to the mechanism of CCK and gastrin in controlling the growth of tumors, enriched our view to the mechanism of apoptosis of alimentary tract tumors, and has provided a new thinking for the assistant treatment to bile duct carcinoma cells as well.

Bcl-2家族在胃癌中的表达研究

目的比较胃癌与癌旁组织中Bcl-2、Bcl-xL和Bax的表达,探讨它们在胃癌发生发展中的作用。方法用免疫组化法分别检测胃癌组织与癌旁组织各55例中Bcl-2、Bcl-xL和Bax的蛋白表达情况。结果癌组织和癌旁组织的Bcl-2、Bax蛋白表达均无显著性差异(P>0.05);癌组织Bcl-xL蛋白表达明显高于癌旁组织(P<0.05)。结论Bcl-xL的表达明显强于Bcl-2,说明Bcl-xL在胃癌发生发展中可能起着更为重要的作用。

bcl-2及相关基因在番茄红素诱导人胃癌细胞凋亡过程中的作用

目的通过体外试验研究bcl-2及相关基因在番茄红素诱导人胃癌SGC-7901细胞凋亡过程中的作用。方法将番茄红素作用于人胃癌SGC-7901细胞,DAPI染色观察细胞凋亡情况,RT-PCR法检测bcl-2、bax、p53mRNA的表达。结果番茄红素作用于人胃癌SGC-7901细胞后,细胞发生凋亡,凋亡率为78.5%;随番茄红素浓度的增加,bcl-2mRNA的表达明显降低,baxmRNA和p53mRNA的表达均显著增加,并均呈剂量-效应关系。结论番茄红素在体外能诱导人胃癌SGC-7901细胞凋亡,且以促进p53mRNA过表达,从而上调baxmRNA的表达,下调bcl-2mRNA表达,即通过改变bax与bcl-2的比例来促进人胃癌SGC-7901细胞凋亡。

Effects of ATRA, Acitretin and Tazarotene on Growth and Apoptosis of Tca8113 Cells

Summary：To investigate the effects of ATRA, acitretin and tazarotene on the growth and apoptosis of human tongue squamous cell carcinoma cell line Tca8113. The effect of retinoids on growth of Tca8113 cells in vitro was examined by MTT assay and Trypan blue exclusion assay. Cell cycle analysis, early apoptosis analysis with double staining with Annexin V-FITC and PI, and active caspase-3 analysis with the staining of FITC-conjugated monoclonal rabbit anli-active caspase-3 antibody were made by flow cytometer. Streptavidin-biotin complex （SABC） immunocytochemical assays were employed for the detections of Bax/Bcl-2 proteins expressions. Our results showed that the retinoids inhibited growth of Tca8113 cells in a dose-and time-dependent manner with maximal inhibition 24 h after treatment of 10 5 mol/L. 10^-5 mol/L retinoids altered cell cycle distribution of Tca8113 cells, revealing an increase in G0/G1-phase population, a decrease in S-phase population and the inhibition of G1/S switching. 10^-5 mol/L retinoids significantly induced apoptosis of Tca8113 cells （all P〈0.05）, elevated the cells population with detectable active caspase-3 （P〈 0.05 for all）, increased the number of cells forming Bax and decreased the number of cells forming Bcl-2 significantly （all P〈0.05）. Acitretin played a most prominent role among the retinoids. It is concluded that the inhibition of cell cycle progress of Tca8113 cells by ATRA, acitretin and tazarotene is one of the possible mechanisms for proliferation arrest of TcaS113 cells elicited by the retinoids. The retinoids mediate apoptosis in TcaS113 cells that may be caspase-dependent through mitochondria pathway. High concentration retinoids inhibit growth of Tca8113 cells in vitro by interfering with proliferation and inducing apoptosis of cells. Acitretin may be an alternative medicine for the prevention and treatment of tongue squamous cell carcinoma.

Apoptotic cell death and its relationship to gastric carcinogenesis

AIM: To investigate the apoptotic process of cells with in the intestinal metaplasia areas co-localizing with chronic gastritis and gastric carcinomas and to analyze the involvement of proteins regulating apoptosis in the process of intestinal metaplasia related gastric carcinogenesis. METHODS: Forty-two gastric carcinoma and seventeen chronic gastritis cases were included in this study. All cases were examined for the existence of intestinal metaplasia. Ten cases randomly selected from each group were processed for TUNEL assay. TUNEL positive cells within the intestinal metaplasia areas, co-localizing either to gastric carcinoma or chronic gastritis, were counted and converted to apoptotic indices. In addition, p53, bcl-2 and bax expression patterns within these tissues were analyzed on the basis of immunohistochemistry. RESULTS: Twenty-eight of the cases were intestinal and 14 of the cases were diffuse type adenocarcinomas. 64% (27/42) of the gastric carcinoma cases had intestinal metaplasia. Intestinal metaplasia co-localized more with intestinal type carcinomas compared with diffuse type carcinomas [75% (21/28) vs 42% (6/14), respectively; P ≤0.05]. The mean apoptotic index in tumor cells was 0.70±0.08. The mean apoptotic index in intestinal metaplasias co-localizing to tumors was significantly higher than that of intestinal metaplasias co-localizing to chronic gastritis (0.70±0.03 vs 0.09±0.01, respectively; P≤0.05). p53 positivity was not observed in areas of intestinal metaplasia adjacent to tumors or chronic gastritis. Intestinal metaplasia areas adjacent to tumors showed lower cytoplasmic bcl-2 positivity compared to intestinal metaplasia areas adjacent to chronic gastritis [55.5% (15/27) vs 70.5% (12/17), respectively]. On the other hand, intestinal metaplasia areas adjacent to tumors showed significantly higher cytoplasmic bax positivity compared to intestinal metaplasia areas adjacent to chronic gastritis [44.4% (12/27) vs 11.7% (2/17), respectively; P ≤0.05]. CONCLUSION: Existence of apoptotic cells on the basis of TUNEL positivity is shown in intestinal metaplasias co-localizing to both diffuse and intestinal type gastric cancers in this study. Our results also suggested bax expression dependent induction of apoptosis especially in intestinal metaplasia areas adjacent to tumors. These findings strongly support the involvement of apoptotic mechanisms in the process of gastric carcinogenesis especially in the transition from intestinal metaplasia to gastric cancer. It may be suggested that induction of apoptosis in intestinal metaplasia areas adjacent to tumors may involve different mechanisms than induction by chronic inflammation.

人参多糖注射液对胃癌细胞SGC-7901凋亡的诱导作用及机制

目的:人参多糖注射液对胃癌细胞SGC-7901凋亡的诱导作用及机制.方法:采用不同浓度(0、12.5、25.0、50.0、100.0μL/m L)、不同时间(24、48、72 h)人参多糖注射液处理SGC-7901细胞,分别采用流式细胞仪及Western blot检测细胞凋亡及Bax、Bcl-2蛋白表达.结果:人参多糖注射液对SGC-7901细胞体外凋亡具有显著的促进作用,并呈现剂量及时间依赖性.人参多糖注射液处理后,SGC-7901细胞Bax蛋白表达及Bax/Bcl-2蛋白表达比值显著升高,Bcl-2蛋白表达显著降低,并呈现剂量及时间依赖性.结论:人参多糖注射液可诱导胃癌SGC-7901细胞凋亡,调节凋亡相关基因Bax、Bcl-2表达是其可能作用机制.

解毒消癥饮诱导胃癌细胞凋亡相关基因表达的研究

目的:探讨中药复方解毒消癥饮对人胃癌细胞凋亡相关基因表达的影响。方法:将人胃癌细胞株BGC-823分成空白对照组及药物干预低、中、高剂量组,分别加入空白对照血清和相应剂量的解毒消癥饮大鼠含药血清,培养24h、48h和72h;免疫荧光染色法检测细胞凋亡相关基因Bax、Bcl-2、Fas及Fas-L的表达,应用激光共聚焦显微镜观察并做半定量分析;另行电镜制样、观察。结果:胃癌细胞经解毒消癥饮含药血清干预后,Bax、Fas表达明显增加(P<0.05),且随药物浓度增加该趋势更加明显,Fas-L则随药物浓度的增加表达明显减弱(P<0.05);Bcl-2表达量无明显变化。电镜见胃癌细胞出现早期凋亡现象,主要为细胞核异染色质边聚;线粒体嵴消失、基质深染。结论:解毒消癥饮可能通过调控胃癌细胞Bax、Fas及Fas-L等基因,从而促进细胞凋亡,并降低细胞免疫逃逸的功能。