Effects of gastrin 17 on β-catenin/Tcf-4 pathway in Colo320WT colon cancer cells

AIM: To explore the effect of gastrin 17 (G17) on beta-catenin/T cell factor-4 (Tcf-4) signaling in colonic cancer cell line Colo320WT. METHODS: The pCR3.1/GR plasmid, which expresses gastrin receptor, cholecystokinin-2 receptor (CCK-2R), was transfected into a colonic cancer cell line Colo320 by Lipofectamine (TM)2000 and the stably expressing CCK-2R clones were screened by G418. The expression levels of gastrin receptor in the Colo320 and the transfected Colo320WT cell line were assayed by RT-PCR. Colo320WT cells were treated with G17 in a time-dependent manner (0, 1, 6, 12, 24 and 48 h), then with L365,260 (Gastrin(17) receptor blocker) for 30 min, and with G17 again for 12 h or L365,260 for 12 h. Expression levels of beta-catenin in a TX-100 soluble fraction and TX-100 insoluble fraction of Colo320WT cells treated with G17 were detected by co-immuniprecipation and Western blot. Immunocytochemistry was used to examine the distribution of beta-catenin in CoLoWT320 cells. Expression levels of c-myc and cyclin D1 in Colo320WT cells treated with G17 were assayed by Western blot. RESULTS: Expression levels of beta-catenin in the TX-100 solution fraction decreased apparently in a time-dependent fashion and reached the highest level after G17 treatment for 12 h, while expression levels of beta-catenin in the TX-100 insoluble fraction were just on the contrary. Immunocytochemistry showed that beta-catenin was translocated from the cell membranes into the cytoplasm and nucleus under G17 treatment. Expression levels of c-myc and cyclin D1 in the G17-treated Colo320WT cells were markedly higher compared to the untreated Colo320WT cells. In addition, the aforementioned G17-stimulated responses were blocked by L365,260. CONCLUSION: Gastrin17 activates beta-catenin/Tcf-4 signaling in Colo320WT cells, thereby leading to over-expression of c-myc and cyclin D1.     

Expression pattern of leptin and leptin receptor （OB-R） in human gastric cancer

INTRODUCTION Previous studies have shown a positive association be- tween adiposity and increased risk of cancers of the endo- metrium, kidney, gallbladder (in women), breast (in post- menopausal women), and colon (particularly in men)[1-9]. Consistently,…     

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. Scores 1-3 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 vslow = 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,vslow = 5.600; P<0.05, x2middle 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, x2high vs low = 4.710; P<0.05, x2middle 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 gastrin and its receptor in human gastric cancer tissues

Purpose: Gastrin is a growth factor of cancerous and normal cells of the gastrointestinal tract, and its effect is known to be mediated by gastrin/cholecystokinin B (CCKB) receptor. This study was performed to investigate the prognostic significance and the expression profiles of gastrin and gastrin receptor in human gastric carcinoma tissues. Methods: We analyzed the expressions of gastrin and gastrin receptor by immunohistochemical staining using anti-gastrin Ab (Sigma, St. Louis, MO, USA) and anti-gastrin receptor Ab (Aphton Corp., Woodland, CA, USA) in 279 gastric adenocarcinoma patients. Patients’ clinicopathologic features and prognoses were analyzed. Results: The gastrin expression rate in these patients was 47.7% (133/279) and the gastrin receptor expression rate was 56.5% (158/279). Gastrin expression was significantly higher in men than in women (54.3% vs. 34.1%), and higher in differentiated gastric adenocarcinoma than in the undifferentiated type (55.1% vs. 43.0%). The gastrin receptor expression rate was also significantly higher in men than in women (61.2% vs. 47.3%), and was higher in the differentiated type than in the undifferentiated type (72.9% vs. 46.5%), and significantly higher in the intestinal type than in the diffuse type (75.2% vs. 42.9%). Gastrin and gastrin/CCKB receptor expressions were not found to be significant prognostic factors in themselves. When focused on correlation between the co-expression of gastrin and gastrin/CCKB receptor and the survival, the prognosis of patients positive for both gastrin and gastrin receptor was significantly poorer than for those negative for gastrin and gastrin receptor in diffuse-type gastric cancer patients. However, multivariate analysis showed that only TNM stage was an independent prognostic factor of survival in diffuse-type gastric cancer patients. Conclusions: This study shows that the expression rates of gastrin and gastrin receptor are high (about a half) in gastric carcinoma tissues, and that there is an association between gastrin and gastrin receptor expression. We also found that patients with diffuse-type gastric carcinoma tissues expressing both gastrin and gastrin receptor have a poorer prognosis than those negative for both, which suggests that gastrin acts as an autocrine growth factor in a subgroup of gastric carcinomas.     

Differential expression of gastrin, cholecystokinin-A and cholecystokinin-B receptor mRNA in human pancreatic cancer cell lines.

BACKGROUND: It has been assumed that gastrin stimulates the growth of pancreatic cancer in an autocrine way through co-expression of gastrin and the cholecystokinin-B receptor (CCK-BR). However, pancreatic cancer cell lines established directly from patients have revealed a great heterogeneity in cell proliferation when exposed to CCK, gastrin and their receptor antagonists. The aim of this study was therefore to examine co-expression of CCK-A and CCK-B receptor (CCK-AR and CCK-BR), and gastrin mRNA as well as the secretion of CCK and gastrin peptides in these cell lines. METHODS: Fourteen cell lines were established from primary pancreatic cancers or their metastases. Total RNA was isolated from the cell lines and reverse-transcribed into single-stranded cDNA. A PCR technique based on Taq polymerase-antibody interaction and CCK-AR, CCK-BR and gastrin-specific primers, followed by Southern blot analysis, were the methods used. The incubation mediums were analysed for the presence of secreted CCK/proCCK and gastrin/progastrin peptides by specific radioimmunoassays (RIA). RESULTS: By means of nested Reverse-Transcribed Polymerase Chain Reaction (nested RT-PCR), combined with Southem blot analysis of the PCR amplified products, CCK-AR and gastrin mRNA co-expression was detected in cell lines LPC-6p and LPC-10m, whereas CCK-BR and gastrin mRNA could be detected in cell lines LPC-8p and LPC-12m. A low level of secreted CCK peptides was detected in cell line LPC-6p, which also expressed CCK-AR mRNA. In no other cases were CCK or gastrin peptides detected in the cell culture mediums. CONCLUSION: The lack of CCK-BR and gastrin mRNA co-expression, and not detectable levels of secreted CCK and gastrin in culture media, does not lend support to the hypothesis that concomitant gene-expression of CCK receptors and gastrin or CCK are essential to maintaining pancreatic cancer cell proliferation.     

胃泌素及其受体拮抗剂对BGC－823细胞系生长的调节

本文用液闪测定和细胞计数观察了胃泌素及其受体拮抗剂丙谷胺和Ｌ－３６５２６０对体外培养的人胃腺癌ＢＧＣ－８２３细胞系的生长调节作用。结果表明不同浓度胃泌素对ＢＧＣ－８２３细胞系的生长均有显著促进作用，而这种作用可被其受体拮抗剂丙谷胺和Ｌ－３６５２６０所抑制，且发现在胃泌素浓度衡定时，Ｌ－３６５２６０对ＢＧＧ－８２３细胞系的生长抑制作用明显强于丙谷胺。这一结果也提示，Ｌ－３６５２６０对胃泌素受体的亲合力可能明显高于丙谷胺。     

促胃液素及其受体拮抗剂丙谷胺对人胃癌细胞系生长的影响

目的观察和分析五肽促胃液素ＰＧ及其受体拮抗剂丙谷胺ＰＧＭ对人胃癌细胞系ＭＧＣ生长的影响,为临床应用促胃液素受体拮抗剂协助治疗胃癌提供依据．方法选用５ｍｇ／Ｌ,１０ｍｇ／Ｌ,１５ｍｇ／Ｌ,２０ｍｇ／Ｌ４种浓度的ＰＧ和３０ｍｇ／Ｌ的ＰＧＭ分别作用于体外培养的浓度为２５×１０８／Ｌ的ＭＧＣ,分别培养２４,４８,７２ｈ,于酶标仪上选用波长５４０ｎｍ测定吸光值Ａ,并对数据进行比较分析．结果４种浓度的ＰＧ作用于ＭＧＣ,ＭＧＣ连续３ｄ的生长状态与对照组无明显差异,而ＭＧＣ在ＰＧＭ作用下,其连续３ｄ的平均Ａ值分别为００２９,００４６和００８４,而未被ＰＧＭ作用的ＭＧＣ的平均Ａ值分别是０１０１,０１１５和０１８２,ＭＧＣ在ＰＧＭ作用下生长明显低于对照组（Ｐ＜００５）．结论外源性的ＰＧ对ＭＧＣ无营养促进作用,而ＰＧＭ能抑制ＭＧＣ的生长     

胃泌素/胆囊收缩素受体环对胃癌细胞增殖迁移的影响

目的探索胃泌素/胆囊收缩素受体环对胃癌细胞增殖迁移的影响。方法用免疫细胞化学方法检测人胃癌细胞SGC-7901、AGS和胃黏膜上皮细胞GES-1细胞中胆囊收缩素-B(CCKB)受体的表达。分别培养这3种细胞,用不同终浓度胃泌素(10、100 nmol/L)处理细胞,以未加胃泌素的细胞为对照,用细胞划痕实验和四甲基偶氮唑盐比色法检测细胞的增殖迁移能力。结果胃癌细胞SGC-7901、AGS中CCKB受体表达强阳性,而GES-1细胞中CCKB受体表达弱阳性;不同浓度胃泌素处理细胞后,SGC-7901、AGS细胞的增殖迁移能力明显增强,而GES-1细胞无明显改变;对照组、10 nmol/L胃泌素处理组及100 nmol/L胃泌素处理组中SGC-7901细胞的相对增殖率分别为100%、191.13%、212.65%,AGS细胞的相对增殖率分别为100%、189.27%、209.19%,各组间差异均有统计学意义(P均<0.01);而GES-1细胞的相对增殖率分别为100%、113.01%、116.12%,各组间差异无统计学意义(P均>0.05)。结论 CCKB受体表达水平的高低对胃泌素/CCKB受体环促进胃癌细胞的增殖和迁移起重要作用。     

A specific gastrin receptor in human gastric mucosa

Biological active 125I-synthetic human gastrin (125I- SHG ) appeared to bind specifically on human gastric mucosal membrane preparations. Gastrin binding was reversible, saturable and of high affinity (Kd = 3.44 +/- 3.44 X 10(-10)M) with the binding site (3.66 +/- 0.34 fmol/mg protein) at 37 degrees C for 30 min (pH 7.4). Specific gastrin binding was present in the fundic mucosa and absent from the antral, duodenal, jejunal, and colonic mucosa. Gastrin analogues (tetragastrin, pentagastrin, caerulein, and synthetic human gastrin) inhibited 125I- SHG specific binding. However, the specific gastrin binding was not inhibited by glucagon, insulin, acetylcholine, atropine, histamine, or cimetidine. It was suggested that gastrin and histamine H2 receptor or gastrin and muscarinic cholinergic receptor did not share the same locus.     

胃泌素受体在胃癌中表达的意义

目的研究胃癌组织表达胃泌素受体（ＧＲ）的特征,是临床应用ＧＲ拮抗剂调控胃癌细胞生长的基础。方法应用受体的放射配基结合分析法测定３４例胃癌及癌旁胃粘膜组织ＧＲ含量及亲和力（Ｋｄ）。结果３４例胃癌组织中,１６例胃癌组织ＧＲ阳性,其中２例属低亲和力ＧＲ;１４例属高亲和力ＧＲ,计高含量ＧＲ９例（３９．５４±１４．４３ｆｍｏｌ／ｍｇ蛋白）和低含量ＧＲ５例（６．０３±２．８３ｆｍｏｌ／ｍｇ蛋白）。胃癌组织表达高含量ＧＲ的平均含量较癌旁胃粘膜组织高。胃体癌表达高亲和力ＧＲ的阳性率为７７．８％,胃底贲门癌为５０．０％,而胃窦癌为２１．１％。晚期胃癌表达高亲和力ＧＲ的阳性率为５２．２％,早、中期胃癌为１０．０％。结论４７．１％胃癌组织能表达ＧＲ;高亲和力、高含量ＧＲ在胃体癌、胃底贲门癌中表达的阳性率高;晚期胃癌表达的ＧＲ多属高亲和力。     

siRNA沉默USP22基因对胃癌细胞增殖的抑制作用

目的:探讨小干扰RNA(siRNA)沉默泛素特异性肽酶22(ubiquitin specific peptidase22,USP22)对胃癌细胞增殖的影响.方法:针对USP22基因设计3条siRNA及阴性siRNA,用脂质体Lipofectamine 2000转染胃癌AGS细胞,通过实时定量PCR和Western blot检测转染后AGS细胞USP22基因中mRNA和蛋白表达水平的变化情况,流式细胞术检测细胞周期分布变化情况,CCK8法检测细胞增殖率及抑制率.结果:转染48h后,3条siRNA均能显著抑制USP22 mRNA和蛋白的表达.其中,以转染USP22 siRNA3后效果最明显,mRNA和蛋白表达分别下降80.47%±2.99%和79.40%±3.58%.细胞增殖明显受到抑制,USP22 siR-NA3组细胞增殖抑制率为27.33%±3.49%.细胞周期中G0/G1期细胞增多,S期细胞减少.结论:采用RNA干扰技术能够有效地沉默USP22基因的表达,并显著抑制胃癌细胞的增殖.     

FUT3-miRNA重组质粒对人胃癌KATO-III细胞增殖的影响

目的:研究利用miRNA干扰技术抑制FUT3基因表达对人胃癌KATO-Ⅲ细胞增殖的影响.方法:将前期实验构建成功的2对针对FUT3基因的特异性miRNA表达载体,用脂质体转染入人胃癌KATO-Ⅲ细胞,RT-PCR检测FUT3基因表达水平的变化;免疫细胞化学法、流式细胞术检测其合成抗原sLeA表达变化;MTT法、克隆形成实验检测FUT3基因的表达抑制对KATO-Ⅲ细胞增殖的影响.结果:转染FUT3-miRNA的2个干扰组FUT3基因mRNA相对表达量分别为0.41±0.01,0.36±0.02,明显低于对照组(0.71±0.05)和空载体组(0.65±0.03,P<0.05);细胞表面合成抗原sLeA的表达水平,FUT3-miRNA1组为35.51%±0.36%,FUT3-miRNA2组为26.05%±1.14%,明显低于对照组(52.79%±2.62%)与空载体组(49.75%±1.29%,P<0.05);与对照组(5.60%±0.63%)和空载体组(8.90%±0.91%)相比较,FUT3-miRNA1组(38.10%±1.96%)和FUT3-miRNA2组(49.04%±2.37%)能明显抑制细胞的增殖(P<0.05);细胞的克隆形成能力FUT3-miRNA1组(14.10%±1.70%)和FUT3-miRNA2组(12.50%±1.96%),显著低于对照组(29.79%±3.05%)和空载体组(28.92%±2.10%,P<0.05).结论:FUT3靶向miRNA真核表达载体可有效抑制胃癌细胞的增殖能力.