Induction of apoptosis and G2/M cell cycle arrest by oridonin in human gastric cancer BGC-823 cells

Aim To investigate in vitro apoptosis-induction effects of oridonin on gastric tumor cells BGC-823 and its effects on cell cycle, mitochondrial membrane potential and intracellular Ca^2＋ to shed light on the mode of its anticancer action. Methods The MTT method was used to investigate the inhibitory effect of oridonin on BGC-823 cells. The apoptosis-induction effect was evaluated by confocal laser microscopy and flow cytometry. The change of mitochondrial membrane potential and the increase of intracellular Ca^2＋ were assessed by fluorescence probe rhodamine123 and Fluo 3-AM, respectively, with flow cytometry. The expression of apoptosis and cell cycle related proteins was studied using western blotting. Results Oridonin inhibited BGC-823 cells growth with IC50 of 22.21 p, mol.L^-1. It induced apoptosis in a dose-dependent manner. In addition, it decreased mitochondria membrane potential, increased intracellular Ca^2＋, and activated pro-caspase 3. BGC-823 cells were arrested in G2/M cell cycle phase with lower expression of cyclin A protein. The up-regulation of p53 was observed before apoptosis and cell cycle arrest occurred. Conclusion Oridonin inhibits the proliferation of BGC-823 cells through G2/M cell cycle arrest and apoptosis induction, which is mediated by influx of Ca^2＋, up-regulation of p53, activation of caspase-3, and down-regulation of cyclin A.

Human epidermal growth factor receptor 2 expression level and combined positive score can evaluate efficacy of advanced gastric cancer

BACKGROUND Although treatment options for gastric cancer(GC)continue to advance,the overall prognosis for patients with GC remains poor.At present,the predictors of treatment efficacy remain controversial except for high microsatellite instability.AIM To develop methods to identify groups of patients with GC who would benefit the most from receiving the combination of a programmed cell death protein 1(PD-1)inhibitor and chemotherapy.METHODS We acquired data from 63 patients with human epidermal growth factor receptor 2(HER2)-negative GC with a histological diagnosis of GC at the Cancer Hospital,Chinese Academy of Medical Sciences between November 2020 and October 2022.All of the patients screened received a PD-1 inhibitor combined with chemotherapy as the first-line treatment.RESULTS As of July 1,2023,the objective response rate was 61.9%,and the disease control rate was 96.8%.The median progression-free survival(mPFS)for all patients was 6.3 months.The median overall survival was not achieved.Survival analysis showed that patients with a combined positive score(CPS)≥1 exhibited an extended trend in progression-free survival(PFS)when compared to patients with a CPS of 0 after receiving a PD-1 inhibitor combined with oxaliplatin and tegafur as the first-line treatment.PFS exhibited a trend for prolongation as the expression level of HER2 increased.Based on PFS,we divided patients into two groups:A treatment group with excellent efficacy and a treatment group with poor efficacy.The mPFS of the excellent efficacy group was 8 months,with a mPFS of 9.1 months after excluding a cohort of patients who received interrupted therapy due to surgery.The mPFS was 4.5 months in patients in the group with poor efficacy who did not receive surgery.Using good/poor efficacy as the endpoint of our study,univariate analysis revealed that both CPS score(P=0.004)and HER2 expression level(P=0.015)were both factors that exerted significant influence on the efficacy of treatment the combination of a PD-1 inhibitor and chemotherapy in patients with advanced GC(AGC).Finally,multivariate analysis confirmed that CPS score was a significant influencing factor.CONCLUSION CPS score and HER2 expression both impacted the efficacy of immunotherapy combined with chemotherapy in AGC patients who were non-positive for HER2.

Apoptosis mechanisms of human gastric cancer cell line MKN-45 infected with human mutant p27

AIM: To explore the inducing effect of human mutant p27 gene on the apoptosis of the human gastric cancer cell line MKN-45 and its associated mechanisms. METHODS: The recombinant adenovirus Ad-p27mt was constructed to infect the human gastric cancer cell line MKN-45. Using flow cytometry, TUNEL assay and DNA fragment analysis, we measured the apoptotic effect of Ad-p27mt on the human gastric cancer cells. RESULTS: Ad-p27mt was successfully constructed and the infection efficiency reached 100%. After 18 h of infection, we observed an apoptotic hypodiploid peak on the flow cytometer before G1-S and apoptotic characteristic bands in the DNA electrophoresis. The apoptotic rate detected by TUNEL method was significantly higher in the Ad-p27mt group (89.4±3.12%)compared to the control group (3.12±0.13%, P ＜ 0.01).CONCLUSION: Human mutant p27 can induce apoptosis of the human gastric cancer cells in vitro.

Human induced pluripotent stem cells labeled with fluorescent magnetic nanoparticles for targeted imaging and hyperthermia therapy for gastric cancer

Objective: Human induced pluripotent stem(i PS) cells exhibit great potential for generating functional human cells for medical therapies. In this paper, we report for use of human i PS cells labeled with fluorescent magnetic nanoparticles(FMNPs) for targeted imaging and synergistic therapy of gastric cancer cells in vivo. Methods: Human i PS cells were prepared and cultured for 72 h. The culture medium was collected, and then was coincubated with MGC803 cells. Cell viability was analyzed by the MTT method. FMNP-labeled human i PS cells were prepared and injected into gastric cancer-bearing nude mice. The mouse model was observed using a small-animal imaging system. The nude mice were irradiated under an external alternating magnetic field and evaluated using an infrared thermal mapping instrument. Tumor sizes were measured weekly. Results: iP S cells and the collected culture medium inhibited the growth of MGC803 cells. FMNP-labeled human iP S cells targeted and imaged gastric cancer cells in vivo, as well as inhibited cancer growth in vivo through the external magnetic field. Conclusion: FMNP-labeled human i PS cells exhibit considerable potential in applications such as targeted dual-mode imaging and synergistic therapy for early gastric cancer.

H pylori stimulates proliferation of gastric cancer cells through activating mitogen-activated protein kinase cascade

AIM: To explore the mechanism by which H pylori causes activation of gastric epithelial cells. METHODS: A VacA (+) and CagA (+) standard H pylori line NCTC 11637 and a human gastric adenocarcinoma derived gastric epithelial cell line BGC-823 were applied in the study. MTT assay and 3H-TdR incorporation test were used to detect the proliferation of BGC-823 cells and Western blotting was used to detect the activity and existence of related proteins. RESULTS: Incubation with H pylori extract increased the proliferation of gastric epithelial cells, reflected by both live cell number and DNA synthesis rate. The activity of extracellular signal-regulated protein kinase (ERK) signal transduction cascade increased within 20 min after in- cubation with H pylori extract and appeared to be a sus- tained event. MAPK/ERK kinase (MEK) inhibitor PD98059 abolished the action of H pylori extract on both ERK activity and cell proliferation. Incubation with H pylori extract increased c-Fos expression and SRE-dependent gene expression. H pylori extract caused phosphorylation of several proteins including a protein with molecular size of 97.4 kDa and tyrosine kinase inhibitor genistein inhibited the activation of ERK and the proliferation of cells caused by H pylori extract. CONCLUSION: Biologically active elements in H pylori extract cause proliferation of gastric epithelial cells through activating tyrosine kinase and ERK signal trans- duction cascade.

A COMPARISON OF THE PROTOONCOGENES BETWEEN THE HUMAN GASTRIC CANCEROUS AND NORMAL MUCOSAL TISSUES

The allelic distribution of EcoRI and BamHI fragments of ras family genes between the human primary gastric cancer tissues and the corresponding adjacent normal tissues did not show any differences. Three genotypes of BamHI restriction fragment length polymorphism of c-H-ras were revealed. No significant differences in the RFLPs were observed between normal individuals and gastric cancer patients. Four protooncogenes, c-H-ras, N-ras, c-myc and c-fos, were found to be transcriptionally active in the gastric cancer tissues in some cases examined. The comparison of the expression of these oncogenes between the malignant tissues and the corresponding normal tissues showed differential patterns. The expression of c-H-ras at cellular level was detected by in situ hybridization. The enhanced expression of c-H-ras in the gastric cancer cells was demonstrated, but the degree of the expression among the cancer cells was shown to be heterogeneous. In addition, the enhanced expression of c-H-ras was seen in the inflammatory cells.

Telomerase and hTERT: Can they serve as markers for gastric cancer diagnosis?

AIM: To investigate telomerase activity and human telomerase reverse transcriptase (hTERT) expression in normal human gastric mucosal epithelial cells (nhGMECs) and fibroblasts (nhGMFs).

Colony-stimulating factor 3 and its receptor promote leukocyte immunoglobulin-like receptor B2 expression and ligands in gastric

BACKGROUND Colony-stimulating factor 3(CSF3)and its receptor(CSF3R)are known to promote gastric cancer(GC)growth and metastasis.However,their effects on the immune microenvironment remain unclear.Our analysis indicated a potential link between CSF3R expression and the immunosuppressive receptor leukocyte immunoglobulin-like receptor B2(LILRB2)in GC.We hypothesized that CSF3/CSF3R may regulate LILRB2 and its ligands,angiopoietin-like protein 2(ANGPTL2)and human leukocyte antigen-G(HLA-G),contributing to immunosuppression.AIM To investigate the relationship between CSF3/CSF3R and LILRB2,as well as its ligands ANGPTL2 and HLA-G,in GC.METHODS Transcriptome sequencing data from The Cancer Genome Atlas were analyzed,stratifying patients by CSF3R expression.Differentially expressed genes and immune checkpoints were evaluated.Immunohistochemistry(IHC)was performed on GC tissues.Correlation analyses of CSF3R,LILRB2,ANGPTL2,and HLA-G were conducted using The Cancer Genome Atlas data and IHC results.GC cells were treated with CSF3,and expression levels of LILRB2,ANGPTL2,and HLA-G were measured by quantitative reverse transcriptase-polymerase chain reaction and western blotting.RESULTS Among 122 upregulated genes in high CSF3R expression groups,LILRB2 showed the most significant increase.IHC results indicated high expression of LILRB2(63.0%),ANGPTL2(56.5%),and HLA-G(73.9%)in GC tissues.Strong positive correlations existed between CSF3R and LILRB2,ANGPTL2,and HLA-G mRNA levels(P<0.001).IHC confirmed positive correlations between CSF3R and LILRB2(P<0.001),and HLA-G(P=0.010),but not ANGPTL2(P>0.05).CSF3 increased LILRB2,ANGPTL2,and HLA-G expression in GC cells.Heterogeneous nuclear ribonucleoprotein H1 modulation significantly altered their expression,impacting CSF3’s regulatory effects.CONCLUSION The CSF3/CSF3R pathway may contribute to immunosuppression in GC by upregulating LILRB2 and its ligands,with heterogeneous nuclear ribonucleoprotein H1 playing a regulatory role.

胃癌组织中SDF-1、HER2及Slug表达与患者临床病理特征的相关性

目的分析基质细胞衍生因子1(SDF-1)、人表皮生长因子受体2(HER2)、锌指转录因子(Slug)在胃癌组织内的表达及与患者临床病理特征间的关系。方法选取73例胃癌患者,采集其癌组织与癌旁正常组织,以免疫组织化学法检测对比两者SDF-1、HER2及Slug的表达差异;另收集患者的年龄等资料,统计分析SDF-1、HER2及Slug表达与胃癌患者各项临床病理特征间的联系。结果癌组织的SDF-1、HER2、Slug阳性表达率高于癌旁正常组织,差异有统计学意义(P<0.05)。SDF-1、HER2、Slug阳性表达与胃癌患者的年龄、性别无关(P>0.05),与患者的临床分期、淋巴结转移、分化程度有关(P<0.05)。结论SDF-1、HER2、Slug在胃癌组织内呈异常高表达,且其参与胃癌的侵袭、发展过程。

Expression of annexin II in gastric carcinoma and its role in gastric cancer metastasis

AIM To investigate the expression of annexin II in gastric carcinoma and its role in the metastasis of gastric cancer.METHODS The expression of annexin II in 51 cases of gastric carcinoma and 24 cases of adjacent tissues was detected by immunohistochemistry. The relationship between annexin II and clinical features of gastric cancer was analyzed. Annexin II specific si RNA was used to inhibit the expression of annexin II in gastric cancer HGC-27 cells, and the effects of annexin II on the migration and secretion of matrix metalloproteinases(MMPs) were observed.RESULTS The positive rate of annexin II protein was 82.4% in gastric cancer tissues and 37.5% in adjacent tissues. There was significant difference between the two groups(P < 0.01); and the positive expression of annexin II was not related to the sex and age of the patients(P > 0.05). The expression of annexin IIprotein was correlated with tumor size, histological differentiation, TNM stage, Lymph node metastasis and other clinical features were significantly correlated, the difference was statistically significant(P < 0.05). Inhibition of annexin II expression, gastric cancer HGC-27 cells migration and secretion of MMPs were significantly decreased, the difference was statistically significant(P < 0.05).CONCLUSION Annexin II is highly expressed in gastric cancer tissues, annexin II protein expression is related to tumor size, histological differentiation, TNM staging, lymph node metastasis and other clinical features were significantly correlated. Annexin II high expression can promote the invasion and metastasis of gastric cancer.

Selective inhibition of cell growth by activin in SNU-16 cells

AIM： To investigate whether activin regulates the cell proliferation of human gastric cancer cell line SNU-16 through the mRNA changes in activin receptors, Smads and p21^CIP1/WAF1. METHODS： The human gastric cancer cell lines were cultured, RNAs were purified, and RT-PCRs were carried out with specifically designed primer for each gene. Among them, the two cell lines SNU-5 and SNU-16 were cultured with activin A for 24, 48 and 72 h. The cell proliferation was measured by MTT assay. For SNU-16, changes in ActRIA, ActRIB, ActRIIA, ActRIIB, Smad2, Smad4, Smad7, and p21^CIP1/WAF1 mRNAs were detected with RT-PCR after the cells were cultured with activin A for 24, 48 and 72 h. RESULTS： The proliferation of SNU-16 cells was down regulated by activin A whereas other cells showed no change. Basal level of inhibin/activin subunits, activin receptors, Smads, and p21^CIP1/WAF1 except for activin βB mRNAs was observed to have differential expression patterns in the human gastric cancer cell lines, AGS, KATO III, SNU-1, SNU-5, SNU-16, SNU-484, SNU-601, SNU-638, SNU-668, and SNU-719. Interestingly, significantly higher expressions of ActR IIA and IIB mRNAs were observed in SNU-16 cells when compared to other cells. After activin treatment, ActR IA, IB, and IIA mRNA levels were decreased whereas ActR IIB mRNA level increased in SNU-16 cells. Smad4 mRNA increased for up to 48 h whereas Smad7 mRNA increased sharply at 24 h and returned to the initial level at 48 h in SNU-16 cells. In addition, expression of the p21^CIP1/WAF1 the mitotic inhibitor, peaked at 72 h after activin treatment in SNU-16 cells. CONCLUSION： Our results suggest that inhibition of cell growth by activin is regulated by the negative feedback effect of Smad7 on the activin signaling pathway, and is mediated through p21^CIP1/WAF1 activation in SNU-16 cells.

DADS下调DJ-1通过PTEN/Akt通路抑制人胃癌MGC803细胞侵袭与上皮-间质转化

目的:探讨二烯丙基二硫(diallyl disulfide,DADS)下调DJ-1通过PTEN/Akt通路抑制人胃癌MGC803细胞侵袭与上皮-间质转化的作用。方法:实验分为MGC803组、空载体组、DJ-1过表达组、MGC803+DADS组、空载体+DADS组、DJ-1过表达+DADS组。MTT、平板克隆、细胞划痕和侵袭实验检测DADS对MGC803细胞增殖、克隆形成、迁移与侵袭的影响;相差显微镜观察DADS对MGC803细胞形态学的影响;qRT-PCR、Western blot与免疫荧光检测DJ-1、PTEN、p-Akt、Snail、Vimentin、E-cadherin、MMP-9与TIMP-3表达。结果:MTT显示,24 h、48 h和72 h后,DADS处理后,各组细胞的增殖率分别较处理前下降(P<0.05)。平板克隆显示,DADS处理后,克隆形成数较处理前各组减少(P<0.05)。划痕实验显示,24 h时,DADS处理后的划痕距离,分别较处理前各组增加(P<0.05)。迁移实验显示,DADS处理后,各组的迁移细胞较处理前各组减少(P<0.05)。侵袭实验显示,DADS处理后,侵袭细胞较处理前减少(P<0.05)。DADS处理后,DJ-1表达较处理前下降(P<0.05),PTEN表达较处理前上调(P<0.05),免疫荧光与上述结果一致。DADS处理后,各组p-Akt表达下调(P<0.05)。相差显微镜显示,DADS处理后,MGC803组与DJ-1过表达组异型性下降,Snail、Vimentin与MMP-9表达下调,E-cadherin与TIMP-3表达上调(P<0.05)。结论:DADS下调DJ-1可负调控PTEN/Akt通路抑制人胃癌MGC803细胞侵袭与上皮-间质转化。

Effects of human microRNA-181a-5p on proliferation and migration of gastric cancer cells

Objective To preliminarily explore the effects of human microRNA-181a on migration of gastric cancer cells and its mechanism.Methods The expression of miRNA-181a-5p in gastric cancer cell line GC9811 and peritoneal high metastasis gastric cancer cell line GC9811-P were tested by quantitative real-time polymerase chain reaction(qRT-PCR).GC9811 cell line was

南方红豆杉水提物对HER2阳性人NCI-N87胃癌移植瘤生长及凋亡作用

目的:探讨南方红豆杉水提物对HER2阳性人胃癌NCI-N87细胞裸鼠移植瘤的抑制作用,及诱导凋亡的作用。方法:通过建立人胃癌NCI-N87细胞裸鼠移植瘤模型,采用随机数字法将80只裸鼠随机分为8组:生理盐水对照组,南方红豆杉低、中、高剂量组,西药赫赛汀组,南方红豆杉低、中、高剂量联合赫赛汀组;给药处理后颈椎脱臼法处死裸鼠,剥离瘤组织,称瘤重、测量瘤径,计算移植瘤体积,绘制肿瘤生长曲线,计算瘤重得抑瘤率;TUNEL法检测移植瘤细胞凋亡,计算凋亡指数。结果:同对照组比较治疗组均可抑制肿瘤生长(P<0.05),且联合组表现出比单药组更为显著的抑制作用;中剂量联合组对肿瘤的抑制作用优于红豆杉高剂量及赫赛汀单药组(P<0.05)。对照组凋亡细胞数少,凋亡率低,低、中、高剂量单药组均可见到凋亡细胞,凋亡率同对照组比较(P<0.05);各剂量联合用药组凋亡细胞数目较多,与单药组比较均有明显差异(P<0.05),中剂量联合组差异性最为显著(P<0.01)。结论:南方红豆杉水提物对HER2阳性高表达NCI-N87胃癌裸鼠移植瘤的生长有抑制作用,联合赫赛汀可以增强其增殖抑制效果,中剂量联合组显著提高赫赛汀的抑瘤作用;南方红豆杉水提物可以促进胃癌细胞的凋亡,联合赫赛汀能增强其诱导凋亡作用。

着丝粒蛋白-H对人胃癌细胞增殖的影响

目的检测着丝粒蛋白-H(CENP-H)基因在人胃癌细胞系中的表达情况,研究CENP-H对胃癌细胞增殖的影响。方法采用QPCR、Western blot检测7株胃癌细胞系及永生化人胃粘膜上皮细胞中CENP-H的mRNA和蛋白表达水平。用重组逆转录病毒感染胃癌细胞,建立稳定干扰内源性及高表达外源性CENP-H的胃癌细胞系,并利用Western blot及QPCR检测进行鉴定,最后采用MTT、平板克隆形成实验分析CENP-H对胃癌细胞增殖能力的影响。结果人胃癌细胞系中CENP-H蛋白及mRNA表达水平均高于永生化人胃粘膜上皮细胞。Western blot及QPCR鉴定结果表明成功建立稳定沉默内源性及高表达外源性CENP-H的胃癌细胞系。MTT、平板克隆形成实验显示干扰CENP-H后对胃癌细胞增殖能力起到抑制作用,过表达CENP-H后能促进胃癌细胞增殖。结论 CENP-H对胃癌细胞的增殖具有重要的作用,在胃癌的发生发展中可能扮演重要角色。

胃癌中hMSH2、PTEN和PCNA表达的相关性及意义

目的：探讨胃癌中错配修复基因 hMSH2与 PTEN、PCNA 表达的关系及意义。方法：采用免疫组织化学 SP 法检测胃癌、癌旁和胃炎粘膜中 hMSH2、PTEN 和 PCNA 的表达。结果：(1)hMSH2和 PCNA 在癌组织的表达阳性率均显著高于非癌组织；PTEN 在癌组织的表达阳性率显著低于非癌组织。(2)PTEN 在低分化癌和有淋巴结转移的病例表达阳性率显著低于高分化癌和无转移者。PCNA 在低分化癌和有淋巴结转移的病例表达阳性率显著高于高分化癌和无转移者。(3)hMSH2与 PCNA 蛋白表达呈显著性正相关；PTEN 与 PCNA 蛋白表达呈显著性负相关。结论：hMSH2的高表达及 hMSH2与 PCNA 表达的相互影响与胃癌的发生可能有关；检测3种蛋白有助于判断胃癌的恶性程度和生物学行为。

RNAi沉默survivin和HIF-1α基因对胃癌BGC-823细胞体外增殖和凋亡的影响

目的:应用RNA干扰(RNAi)技术抑制胃癌BGC-823细胞中survivin和HIF-1α基因的表达,探讨其对胃癌BGC-823细胞增殖和凋亡的影响。方法:分别设计并合成经过化学修饰的靶向survivin和HIF1αmRNA的小干扰RNA(siRNAs),同时合成错义RNA(SCR),采用HifectinⅡ真核体外转染胃癌BGC-823细胞,将转染siRNA-survivin、siRNA-HIF-1α和SCR的各组细胞分别命名为sis组、siH组和SCR组,同时设空白对照组(无血清培养基),RT-PCR法检测各组细胞中survivin和HIF-1αmRNA表达水平。将胃癌BGC-823细胞分为单干扰组(survivin-siRNA,sis组)、联合干扰组(survivin-siRNA+HIF1α-siRNA,sis+siH组)、非靶向特异性组(SCR组)和空白对照组(无血清培养基),MTT法检测各组细胞增殖活性,Western blotting法检测各组细胞中survivin和HIF-1α蛋白表达水平,流式细胞术检测各组细胞凋亡率。结果:与空白对照组比较,sis组细胞中survivin mRNA表达水平和siH组细胞中HIF-1αmRNA表达水平明显降低(P<0.05或P<0.01)。与空白对照组比较,SCR组细胞增殖活性无明显变化(P>0.05),sis组和sis+siH组细胞增殖活性明显降低(P<0.05);与sis组比较,sis+siH组细胞增殖活性明显降低(P<0.05)。与空白对照组比较,sis+siH组细胞中surviving和HIF-1α蛋白表达水平明显降低(P<0.05或P<0.01),细胞凋亡率明显升高(P<0.01)。结论:联合靶向沉默survivin和HIF-1α基因可下调靶基因的表达,抑制胃癌BGC-823细胞增殖,促进细胞凋亡,RNAi基因沉默技术有望成为治疗胃癌的新方法。

Δ133p53表达状态对rmhTNF效应的影响及机制研究

背景与目的:p53异构体在胃癌发生中的作用报道较少。该研究旨在探讨p53异构体Δ133p53在重组改构人肿瘤坏死因子(recombinant mutant human tumor necrosis factor,rmh TNF)干预胃癌细胞系生物学效应中的作用,为胃癌诊断和治疗提供新的依据。方法:采用细胞增殖/毒性检测试剂盒(CCK-8)和流式细胞术,检测不同浓度的rmh TNF单独或联合氟尿嘧啶(5-FU)应用于MKN-45(表达Δ133p53)和SGC-7901(不表达Δ133p53)细胞,观察细胞抑制率和细胞凋亡情况。通过巢式逆转录多聚酶链反应(nested reverse transcriptase-polymerase chain reaction,n RT-PCR)和实时荧光定量多聚酶链反应(real-time polymerase chain reaction,RT-PCR)检测Δ133p53、Gadd45α和Cyclin B1 m RNA的表达变化。结果:rmh TNF单独作用于Δ133p53表达阳性的MKN-45细胞有抑制作用,浓度为50、500 IU/m L的rmh TNF作用24 h后,细胞抑制率分别为24.82%、72.33%(t=-9.558,P<0.01),并可提高5-FU的抑制率,且具有显著的量效和时效关系,5-FU(25μg/m L)、rmh TNF(50 IU/m L)+5-FU(25μg/m L)、rmh TNF(500 IU/m L)+5-FU(25μg/m L)作用于MKN-45细胞24 h后,抑制率分别为18.20%、48.66%、59.83%(F=82.742,P<0.01);rmh TNF(50 IU/m L)+5-FU(25μg/m L)作用于MKN-45细胞24、48、72 h后,抑制率分别为48.66%、68.20%、85.23%(F=128.583,P<0.01)。而对于Δ133p53表达阴性的SGC-7901细胞,浓度为50、500 IU/m L的rmh TNF单独抑制率为2.74%、3.25%,抑制作用不明显(t=-0.121,P>0.05)。流式细胞术显示,rmh TNF不仅单独可引起MKN-45细胞凋亡,而且可显著增强5-FU促细胞凋亡作用,rmh TNF(50 IU/m L)、rmh TNF(50 IU/m L)+5-FU(25μg/m L)、rmh TNF(500 IU/m L)+5-FU(25μg/m L)作用于MKN-45细胞24 h后,凋亡率分别为7.21%、10.13%、15.28%(F=123.931,P<0.05)。在MKN-45中,rmh TNF单独或联合5-FU可下调Δ133p53和Cyclin B1基因,上调Gadd45α基因表达水平。n RT-PCR检测对照组及实验组Δ133p53基因相对表达量分别为0.886、0.499、0.330、0.161(F=240.927,P<0.01);Real-time PCR检测实验组Gadd45α基因相对表达量分别为1.227、1.694、3.394,Cyclin B1基因相对表达量分别为1.221、0.722、0.316。Δ133p53表达水平与Cyclin B1呈正相关(r=0.977,P<0.01),与Gadd45α呈负相关(r=-0.950,P<0.01)。结论:rmh TNF对表达Δ133p53胃癌细胞展现出显著的抑制效应,并能增加传统化疗药物5-FU的疗效,其中部分效应可能是通过调节p53下游分子Cyclin B1和Gadd45α表达实现的,提示Δ133p53可能是rmh TNF治疗胃癌生物学效应的关键靶点。

3-氢化松苓酸B诱导人胃癌HGC-27细胞的程序性死亡

目的研究3-氢化松苓酸B对人胃癌细胞HGC-27程序性死亡的影响。方法 MTT法测定细胞增殖。流式细胞仪测定细胞周期及凋亡率。吖啶橙染色及透射电镜观察细胞自噬;Western blot法检测自噬相关蛋白的表达。结果 3-氢化松苓酸B对HGC-27细胞的增殖具有抑制作用,并呈明显的时间、剂量依赖性。10、20、40μmol/L 3-氢化松苓酸B处理HGC-27细胞24 h后,可将细胞阻滞于G0/G1期,但对细胞凋亡无明显影响。20μmol/L 3-氢化松苓酸B处理HGC-27细胞24 h后,透射电镜观察到大量自噬泡和自噬体,细胞自噬比例随浓度增加而显著提高;3-氢化松苓酸B促进I型微管相关蛋白1轻链3(LC3 I)向II型微管相关蛋白1轻链3(LC3 II)转化,上调肌球蛋白样B淋巴细胞瘤-2(Bcl-2)结合蛋白(Beclin-1)和细胞周期依赖性蛋白激酶抑制因子1A(p21)的表达,并抑制G1/S-特异性周期蛋白-D1(Cyclin D1)的表达。结论 3-氢化松苓酸B可诱导HGC-27细胞发生自噬性死亡,但是对细胞凋亡无明显影响。