Study of targeted and controlled release of 5-fluorouracil-loaded PLA nanoparticles and microspheres on treatment of gastric tumor

The aim of this paper was to evaluate controlled release behavior and the therapeutic efficacy of 5-FU-loaded Poly(lactic acid) (PLA)microspheres to human gastric cancer xenograf4 and the targeting effect of VEGF/5-FU loaded PLA nanoparticles. 5-FU-loaded PLA microspheres were prepared by an emulsion evaporation method, and were characterized by scanning electron microscopy (SEM). 5-FU loaded PLA nanoparticles were characterized by (TEM), and particle size analyzer determined the distribution of nanoparticles size. The release performances of 5-FU microspheres in vitro were studied in PH 7.4 phosphate buffered saline. The therapeutic efficacy of 5-FU-loaded PLA microspheres in vivo were studied using MGC-803 (human stomach cancer) xenograft. 32 nude mice were divided into four groups (n=8), 5-FU loaded PLA microspheres were injected at tumor site. VEGF121 monoclonal antibody was connected with 5-FU loaded PLA nanoparticles through carbodimide. The targeted effect of VEGF 5-FU loaded nanoparticles in vivo were observed by single photon emission computed tomography (SPECT) after tail vein injection at 1 h and 2 h. SEM observation showed that microspheres were spherical, and the diameters of two kinds of microspheres were 1 μm and 5 μm respectively. The mean diameter of nanoparticles was 191.0 nm, and the index of polydispersity was 0.202. The drug was released following biphasic kinetics, initial burst and the following steady phase. 1 μm and 5 μm 5-FU-loaded microspheres both resulted in increased life span (1μm microspheres median survival time=40.63 days, 5 μm microspheres median survival time=62.25 days), against 5-FU pure drug (median survival time=14.5 days). These results strongly suggest that 5-FU-loaded PLA microspheres increase life span of nude mice bearing MGC-803 tumors. After injection for 2 h, almost all the VEGF/5-FU loaded PLA nanoparticles could centralize at the human gastric cancer xenograft sites. That demonstrated VEGF monoclonal antibody remain its bioactivity after connection with nanoparticles, VEGF/5-FU loaded PLA nanoparticles had very exact targeting function for gastric tumor xenograft.     

A phase II trial of oxaliplatin plus S-1 as a first-line chemotherapy for patients with advanced gastric cancer

Background Palliative chemotherapy has been shown to have a survival benefit for patients with recurrent or metastatic gastric cancer. We conducted a Phase II trial to determine the efficacy and safety of S-1 plus oxaliplatin （SOX regimen） as first-line chemotherapy for patients with unresectable locally advanced or metastatic gastric cancer. Methods Eligible patients had measurable lesions and no previous history of chemotherapy （except adjuvant chemotherapy）. Oxaliplatin was administered intravenously at a dose of 130 mg/m2 on day 1. S-1 was administered orally in doses of 80, 100, or 120 mg/d according to body surface areas of 〈1.25 m2, 1.25-1.5 m2, or 〉1.5 m2 respectively; the total dose was divided into two daily doses on days 1-14. Treatments were repeated every 3 weeks until disease progression or intolerable toxicity occurred. Results Forty-three patients were enrolled in the study. All were assessable for efficacy and adverse events. The objective response and disease control rates were 55.8% and 76.7% respectively. The median follow-up time was 16.5 months. The median progression-free survival time was 7 months （95% CI, 5.8-8.2 months） and the median overall survival time was 16.5 months （95% CI, 9.7-23.3 months）. The one-year survival rate was 54.2%. Major adverse reactions were grade 3/4 neutropenia （9.3%） and thrombocytopenia （20.9%）. Conclusion The SOX regimen with oxaliplatin at a dose of 130 mg/m2 was found to be effective and safe as a first-line chemotherapy in Chinese patients with advanced gastric cancer.     

Polylactic Acid Nanoparticles Targeted to Brain Microvascular Endothelial Cells

In this work, blank polylactic acid （PLA） nanoparticles with unstained surface were prepared by the nano-deposition method. On the basis of the preparation, the effect of surface modification on brain microvascular endothelial cells （BMECs） targeting was examined by in vivo experiments and fluorescence microscopy. The results showed that PLA nanoparticles are less toxic than PACA nanoparticles but their BMECs targeting is similar to PACA nanoparticles. The experiments suggest that drugs can he loaded onto the particles and become more stable through adsorption on the surface of PLA nanoparticles with high surface activity. The surface of PLA nanoparticles was obviously modified and the hydrophilicity was increased as well in the presence of non-ionic surfactants on PLA nanoparticles. As a targeting moiety, polysobate 80 （T-80） can facilitate BMECs targeting of PLA nanoparticles.     

Proximal gastric cancer: lymph node metastatic patterns according to different T stages dictate surgical approach

Background As a common form of gastric cancer migration,lymph node metastasis largely affects the surgical treatment and prognosis of gastric cancer.Surgery is the fundamental curative option for gastric cancer that varies depending on different stages.The study aimed to compare the clinicopathological characteristics and lymph node metastatic patterns in patients of proximal gastric cancer with different T stages and investigate a reasonable radical gastrectomy approach in terms of the range of lymphadenectomy for proximal gastric cancer.Methods In our retrospective study,the data of 328 patients of proximal gastric cancer with different T stages were analyzed.By comparing the differences of lymph node metastatic rate and ratio,we investigated the clinicopathological characteristics and metastatic patterns of lymph nodes.Also,we were especially interested in the differences in survival rates between patients with and without No.5 and 6 group metastasis with the same TNM stage.Results The overall lymph node metastatic rate and ratio of advanced proximal gastric cancer were 73.4％ and 23.3％,respectively.The tumors of different T stages were statistically significant in size and differentiation degree （P ＜0.05）,multivariate analysis showed that the depth of tumor invasion was an independent risk factor for lymph node metastasis in proximal gastric cancer （RR,12.025; 95％ CI,2.326 to 62.157; P=0.003）.The overall survival rate of patients with No.5,6 group lymph node metastasis and those without was significantly different,but the differences in survival rates between patients with and without No.5 and 6 group metastasis with the same TNM stage were not statistically significant.Conclusions Different T stages in proximal gastric cancer showed different patterns and characteristics of lymph node metastasis.D2 lymphadenectomy in patients with early gastric cancer had little survival benefit because metastasis to level 2 nodes was rare.Therefore the range of the lymph node dissection in radical gastrectomy     

Destruction of gastric cancer cells to mesothelial cells by apoptosis in the early peritoneal metastasis

This study examined the mechanism by which the gastric cancer cells lead to early peritoneal metastasis. HMrSV5 cells, a human peritoneal mesothelial cell line, were co-incubated with the supernatants of gastric cancer cells. Morphological changes of HMrSV5 cells were observed. The cell damage was quantitatively determined by MTT assay. The apoptosis of HMrSV5 cells was observed under transmission electron microscope. Acridine orange/ethidium bromide-stained condensed nuclei was detected by fluorescent microscopy and flow cytometry. The expressions of Bcl-2 and Bax was immunochemically evaluated. The results showed that conspicuous morphological changes of apoptosis were observed in HMrSV5 cells 24 h after treatment with the supernatants of gastric cancer cells. The supematants could induce apoptosis of HMrSV5 cells in a time-dependent manner. The supernatants could up-regulate the expression of Bax and suppress that of Bcl-2 in HMrSV5 cells. These findings demonstrated that gastric cancer cells can induce the apoptosis of HPMCs through supernatants in the early peritoneal metastasis, The abnormal expressions of Bcl-2 and Bax may contribute to the apoptosis. Anti-apoptosis drugs promise to be adjuvant chemotherapeutic agents in the treatment of peritoneal metastasis of gastric cancer.     

Survival Analysis of Stage Ⅳ Metastatic Gastric Cancer Patients Treated with HangAm-Plus

Objective:To evaluate the efficacy of HangAm-Plus(HAP)on stageⅣmetastatic gastric cancer by analyzing the treated patients'overall survival outcome.Methods:Following the study eligibility,overall survival and one year survival rate of 44 stageⅣmetastatic gastric cancer patients who visited EastWest Cancer Center(EWCC)were analyzed.The study consisted of two arms:HAP treatment only(n=18)and combined treatment of concurrent conventional chemotherapy and HAP(n=26).Patient characteristics by gender,age,surgical intervention,Eastern Cooperative Oncology Group(ECOG)score,treatment duration(4 weeks or≥4 weeks),and lines of the chemotherapy received were assessed.Treatment related side effects were also assessed.Results:The median survival of combined group was longer(10.0 months)than that of HAP group(5.1 months).One-year survival rate of combined treatment group and HAP group was 38.5%±9.5%and 33.3%±11.1%,respectively(P0.05).One-year survival rate of those received more and less than 4-week treatment was 57.1%±18.7%and 8.3%±8.0%,respectively(P=0.001).Conclusions:The study supports the safety and potential efficacy of HAP treatment in prevention of chemo-related side effects for stageⅣmetastatic gastric cancer treated with conventional chemotherapy.Further studies are needed to investigate and confirm the results before applying the treatment in clinical settings.     

Preparation of PLLA/bpV（pic） Microspheres and Their Effect on Nerve Cells

In this study, we prepared PLLA/bpV（pic） microspheres, a bpV（pic） controlled release system and examined their ability to protect nerve cells and promote axonal growth. PLLA microspheres were prepared by employing the o/w single emulsification-evaporation technique. Neural stem cells and dorsal root ganglia were divided into 3 groups in terms of the treatment they received： a routine medium group（cultured in DMEM）, a PLLA microsphere group（DMEM containing PLLA microspheres alone） and a PLLA/bpV（pic） group [DMEM containing PLLA/bpV（pic） microspheres]. The effects of PLLA/bpV（pic） microspheres were evaluated by the live-dead test and measurement of axonal length. Our results showed that PLLA/bpV（pic） granulation rate was（88.2±5.6）%; particle size was（16.8±3.1）%, drug loading was（4.05±0.3）%; encapsulation efficiency was（48.5±1.8）%. The release time lasted for 30 days. In PLLA/bpV（pic） microsphere group, the cell survival rate was（95.2 ±4.77）%, and the length of dorsal root ganglion（DRG） was 718±95 μm, which were all significantly greater than those in ordinary routine medium group and PLLA microsphere group. This preliminary test results showed the PLLA/bpV（pic） microspheres were successfully prepared and they could promote the survival and growth of neural cells in DRG.     

加减抗癌方治疗Ⅳ期转移性胃癌患者的生存分析

Objective：To evaluate the efficacy of HangAm-Plus（HAP）on stageⅣmetastatic gastric cancer by analyzing the treated patients’overall survival outcome.Methods：Following the study eligibility,overall survival and one year survival rate of 44 stageⅣmetastatic gastric cancer patients who visited EastWest Cancer Center（EWCC）were analyzed.The study consisted of two arms：HAP treatment only（n=18）and combined treatment of concurrent conventional chemotherapy and HAP（n=26）.Patient characteristics by gender,age,surgical intervention,Eastern Cooperative Oncology Group（ECOG）score,treatment duration（〈4 weeks or≥4 weeks）,and lines of the chemotherapy received were assessed.Treatment related side effects were also assessed.Results：The median survival of combined group was longer（10.0 months）than that of HAP group（5.1 months）.One-year survival rate of combined treatment group and HAP group was 38.5%±9.5%and 33.3%±11.1%,respectively（P〉0.05）.One-year survival rate of those received more and less than 4-week treatment was 57.1%±18.7%and 8.3%±8.0%,respectively（P=0.001）.Conclusions：The study supports the safety and potential efficacy of HAP treatment in prevention of chemo-related side effects for stageⅣmetastatic gastric cancer treated with conventional chemotherapy.Further studies are needed to investigate and confirm the results before applying the treatment in clinical settings.     

Prognostic significance of metastatic lymph nodes ratio in patients with gastric adenocarcinoma after curative gastrectomy

Background We evaluated the impact of the number of metastatic lymph nodes and the metastatic lymph nodes ratio （the ratio between metastatic lymph nodes and total dissected lymph nodes,MLNR） in patients with gastric adenocaminoma following curative gastrectomy and also analyzed the relationship between the number of removed lymph nodes and prognosis in node-negative gastric cancer.Methods From January 2005 to December 2010,1 390 patients who were diagnosed with gastric adenocarcinoma and underwent curative gastrectomy were included.In particular,lymph node metastasis was not present in 515 patients.The number of metastatic lymph nodes and the metastatic lymph nodes ratio were selected for univariate and multivariate analyses to evaluate their influences on the disease outcome.The survival curve was presented according to the number of removed lymph nodes in node-negative gastric cancer using Kaplan-Meier plots.Results The overall 5-year survival rate was 54％ in this group.Univariate analysis revealed that age category,macroscopic appearance,histological grade,tumor size,depth of primary tumor invasion,number of metastatic lymph nodes,metastatic lymph nodes ratio,tumor,nodes,metastasis-classification （TNM） stage and status of lymphovascular,and vessel invasion have significant impact on survival.The number of metastatic lymph nodes and the metastatic lymph nodes ratio both have significant impact on survival （P ＜0.001）.However,in multivariate analyses,only the metastatic lymph nodes ratio was identified to be an independent prognostic factor （P ＜0.001）.The number of removed lymph nodes in node-negative was a strong prognostic factor of survival,the more lymph nodes dissected,the better the survival.Conclusions The metastatic lymph nodes ratio has more significant prognostic value for survival in patients with gastric cancer following curative gastrectomy than the number of metastatic lymph nodes.The number of removed lymph nodes miaht be an important proanostic factor for gastric cancer without lymph node metastasis.     

Correlation between elevated FOXP3 expression and increased lymph node metastasis of gastric cancer

Background FOXP3 was thought to express in the T-cell lineage exclusively until recently when FOXP3 was shown to be expressed by cancer cells. It was indicated that FOXP3 may play a wider role in biology by endowing tumor cells with immune suppressive activity. However, researches between FOXP3 and lymph node metastasis of gastric cancer were relatively infrequent, so the present work was aimed to investigate the relationship between FOXP3 expression and lymph node metastasis in human gastric cancer.Methods A total of 122 gastric cancer patients were enrolled in this study, and gastric tumor specimens and lymph nodes were acquired. Thirty patients who had chronic superficial gastritis diagnosed by gastroscopy contemporaneously in the Peking University People＇s Hospital were chosen randomly as the control group. Immunohistochemistry was performed to evaluate FOXP3 expression. A survival analysis on the 122 patients was then performed. Then, NCI-N87cell lines were used to confirm FOXP3 expression in gastric carcinoma cells. Finally, evaluation of FOXP3 expression in gastric tumor and peritumor tissues in 12 patients were conducted using immunohistochemistry and Western blotting. A X2 test or Fisher＇s exact test （bilateral） was conducted to compare the percentage of positive percentage staining between groups. Kaplan-Meier analysis was performed for survival analysis.Results FOXP3 was expressed by gastric cancer cells and peritumor epithelial cells. FOXP3 expression was increased in primary tumors （58.2%） than that in control group （26.7%）. In the lymph-node metastasis group, the incidence of lymph node metastasis which was less than 60% had a significant upregulation of FOXP3 in primary tumors and lymph nodes.However, the frequency of FOXP3 expression had no relationship with survival.Conclusion FOXP3 probably has a relationship with lymph node metastasis of gastric cancer.     

5-氟尿嘧啶联合人参皂苷Rg3抑制胃癌细胞的增殖

目的探讨5-氟尿嘧啶（5-Fu）联合人参皂苷Rg3对胃癌细胞增殖的抑制作用。方法MTT法检测5-FU联合Rg3对人胃癌细胞MGC-803和MKN-28细胞增殖的抑制作用。构建体外肿瘤球模型研究5-FU联合人参皂苷Rg3对肿瘤球的生长抑制作用;流式细胞仪检测5-FU联合人参皂苷R驴对MKN-28细胞的凋亡诱导作用“构建胃癌裸鼠移植瘤模型,随机分为生理盐水组（阴性对照组）、5-FU组、Rg3组和5-Fu＋Rg3组（联合给药组）;研究5-Fu联合人参皂苷Rg3对裸鼠移植瘤的生长抑制作用,统计各组肿瘤的大小,绘制肿瘤生长曲线。结果MGC-803胃癌细胞和MKN-28胃癌细胞给药48h后,联合给药组细胞存活率显著低于其他组,差异具有统计学意义（P〈0．01）。MGC-03胃癌细胞肿瘤球和MKN-28胃癌细胞肿瘤球给药7d后,联合给药组肿瘤球体积显著小于其他组,差异具有统计学意义（P〈0．01）。细胞凋亡实验结果显示：联合给药组诱导肿瘤细胞凋亡能力显著强于其他组,差异具有统计学意义（P〈0．01）。荷瘤裸鼠实验结果显示：各给药组均能有效抑制肿瘤的生长,与阴性对照组比较差异具有统计学意义（P〈0．01）。联合给药显著延长荷瘤裸鼠的中位生存期,差异具有统计学意义（P〈0．01）。结论5-Fu与Rg3均具有抗胃癌细胞的作用,二者联合应用是一种潜在的治疗胃癌的有效手段。     

LincRNA-p21敲减对胃癌细胞生长和转移的影响及其作用机制

目的：探讨LincRNA-p21敲减对胃癌细胞增殖、迁移与侵袭的影响,并阐明其作用机制。方法：采用实时荧光定量聚合酶链反应（RT-qPCR）法检测胃癌组织、癌旁组织以及3种胃癌细胞（MGC-803、MKN-45和SGC-790）和正常胃黏膜上皮细胞GES-1中LincRNA-p21mRNA表达水平。以MGC-803细胞作为研究对象,实验分为sh-NC组、sh-LincRNA-p21组和AG490+sh-LincRNA-p21组。sh-NC组MGC-803细胞采用慢病毒感染sh-NC;sh-LincRNA-p21组MGC-803细胞采用慢病毒感染sh-LincRNA-p21;AG490+sh-LincRNA-p21组MGC-803细胞采用慢病毒感染sh-LincRNA-p21后,再采用10 μg·L^-1 AG490处理细胞。采用5-乙炔基-2'-脱氧尿苷（EdU）掺入法检测各组MGC-803细胞EdU掺入百分比,CCK-8法检测各组MGC-803细胞活性,Transwell法检测各组MGC-803细胞迁移数和侵袭数,Western blotting法检测sh-NC组和sh-LincRNA-p21组MGC-803细胞中p-JAK1、p-STAT3和p-STAT5蛋白表达水平。将sh-NC组和sh-LincRNA-p21组MGC-803细胞移植入BALB/c裸鼠颈部皮下成瘤,检测瘤体体积和质量。结果：与癌旁组织比较,胃癌组织中LincRNA-p21mRNA表达水平明显降低（P<0.01）;与GES-1细胞比较,MGC-803、MKN-45和SGC-790细胞中LincRNA-p21表达水平均明显降低（P<0.01）。与sh-NC组比较,sh-LincRNA-p21组MGC-803细胞EdU掺入百分比、细胞活性、细胞迁移数和侵袭数、p-JAK1、p-STAT3和p-STAT5蛋白表达水平均明显升高（P<0.05或P<0.01）;与sh-LincRNA-p21组小鼠比较,AG490+sh-LincRNA-p21组MGC-803细胞活性、细胞迁移数和侵袭数均明显降低（P<0.05或P<0.01）。裸鼠成瘤实验,与sh-NC组比较,sh-LincRNA-p21组小鼠瘤体体积和质量均明显增加（P<0.05或P<0.01）。结论：敲减LincRNA-p21可明显促进胃癌细胞的生长与转移,且该促进作用可能与其促进JAK-STAT信号通路活性有关。     

血管生成素-1在体外对人胃癌细胞生物学作用的研究

目的:探讨人血管生成素-1(Ang1)及其与血管内皮生长因子165(VEGF165)共同作用对人胃癌细胞的生物学作用,研究其在肿瘤发生中的作用机制。方法:应用复制缺陷型腺病毒(Ad)-绿色荧光蛋白(GFP)、Ad-Ang1、Ad-VEGF165和Ad-Ang1 Ad-VEGF165/2转染人胃癌细胞株MGC-803,使用MTT比色法分析它们对胃癌细胞增殖的影响;通过流式细胞仪分析血浆饥饿时其对凋亡的影响;使用免疫细胞化学法检测Ki-67的表达;应用RT-PCR方法半定量检测bcl-2 mRNA、bax mRNA的表达情况。结果:MTT结果显示24、48和72 h Ad-Ang1转染组、Ad-VEGF165转染组和Ad-Ang1 Ad-VEGF165/2转染组吸光度均明显高于Ad-GFP组及对照组(P<0.05);Ad-GFP组与对照组相比无显著差异(P>0.05);Ad-Ang1 Ad-VEGF165/2转染组吸光度明显高于Ad-Ang1转染组和Ad-VEGF165转染组(P<0.05)。流式细胞仪检测结果显示Ad-Ang1、Ad-VEGF165及Ad-Ang1 Ad-VEGF165/2处理组与对照组及空转染组相比均能够显著抑制细胞凋亡(P<0.01)。免疫细胞化学法显示各转染组Ki-67表达强度均显著高于对照组和Ad-GFP组(P<0.01)。RT-PCR结果显示bcl-2 mRNA在各转染组中的表达要明显高于对照组(P<0.05);bax mRNA在各转染组中的表达要明显低于对照组(P<0.05)。结论:Ang1、VEGF165和Ang1 VEGF165/2能够明显促进人胃癌细胞MGC-803增殖,抑制血浆饥饿时的凋亡,Ang1 VEGF165/2组的作用要显著强于Ang1组和VEGF165组。     

血管生成素-1在体外对人胃癌细胞生物学作用的研究

目的：探讨人血管生成素-1（Ang1）及其与血管内皮生长因子165（VEGF165）共同作用对人胃癌细胞的生物学作用,研究其在肿瘤发生中的作用机制。方法：应用复制缺陷型腺病毒（Ad）．绿色荧光蛋白（GFP）、Ad-Ang1、Ad-VEGF165和Ad-Ang1＋Ad-VEGF165／2转染人胃癌细胞株MGC-803,使用MTT比色法分析它们对胃癌细胞增殖的影响;通过流式细胞仪分析血浆饥饿时其对凋亡的影响;使用免疫细胞化学法检测Ki-67的表达;应用RT-PCR方法半定量检测bcl-2mRNA、bax mRNA的表达情况。结果：MTT结果显示24、48和72h Ad-Ang1转染组、Ad-VEGF165转染组和Ad-Ang1＋Ad-VEGF165／2转染组吸光度均明显高于Ad-GFP组及对照组（P〈0．05）：Ad-GFP组与对照组相比无显著差异（P〉0．05）;Ad-Ang1＋Ad-VEGF165／2转染组吸光度明显高于Ad-Ang1转染组和Ad-VEGF165转染组（P〈0．05）。流式细胞仪检测结果显示Ad-Ang1、Ad-VEGF165及Ad-Ang1＋Ad-VEGF165／2处理组与对照组及空转染组相比均能够显著抑制细胞凋亡（P〈0．01）。免疫细胞化学法显示各转染组Ki-67表达强度均显著高于对照组和Ad-GFP组（P〈0．01）。RT-PCR结果显示bcl-2 mRNA在各转染组中的表达要明显高于对照组（P〈0．05）;bax mRNA在各转染组中的表达要明显低于对照组（P〈0．05）。结论：Ang1、VEGF165和Ang1＋VEGF165／2能够明显促进人胃癌细胞MGC-803增殖,抑制血浆饥饿时的凋亡,Ang1＋VEGF165／2组的作用要显著强于Ang1组和VEGF165组。     

姜黄素对胃癌MGC-803细胞磷酸化-丝氨酸/苏氨酸蛋白激酶表达的影响

目的 探讨姜黄素对胃癌MGC-803细胞磷酸化-丝氨酸/苏氨酸蛋白激酶(p-AKT)表达的影响.方法 将MGC-803细胞分为空白对照组和四个药物实验组,各组姜黄素浓度分别为5 μmol/L,10 μmol/L,20 μmol/L,40 μmol/L.经不同浓度的姜黄素作用24 h、48 h、72 h后,应用CCK8法检测姜黄素对MGC-803细胞增殖的影响;应用Annexin V-FITC/PI双染色法测定不同浓度的姜黄素作用24 h后胃癌MGC-803细胞凋亡情况;应用蛋白免疫印迹法检测不同浓度姜黄素作用24 h对MGC-803细胞内p-AKT蛋白表达水平的影响.结果 姜黄素对MGC-803细胞增殖有抑制作用,且呈剂量依赖性和时间依赖性.在5~40 μmol/L浓度范围内,姜黄素呈浓度依赖性地促进MGC-803细胞的凋亡,并下调MGC-803细胞中p-AKT的水平.结论 姜黄素可能是通过抑制p-AKT蛋白的表达和AKT信号通路促进MGC-803细胞凋亡并抑制其增殖.     

氧化苦参碱诱导人胃癌细胞凋亡的实验研究

目的：研究氧化苦参碱诱导人胃癌MGC-803细胞裸鼠移植瘤细胞凋亡的作用机制。方法：制备人胃癌MGC-803细胞裸鼠移植瘤模型,将其随机分为阴性对照组、阳性对照组及氧化苦参碱小、中、大剂量组,观察氧化苦参碱对人胃癌裸鼠移植瘤的抑制作用。流式细胞仪检测移植瘤细胞Bd-2、Bax的表达。结果：氧化苦参碱能有效抑制裸鼠移植瘤的生长,与阴性对照组比较,其大剂量组肿瘤抑制作用明显,平均抑制率为43．20％;流式细胞仪检测显示氧化苦参碱组裸鼠移植瘤细胞Bcl-2表达降低,而Bax表达升高,以中剂量氧化苦参碱诱导细胞凋亡最明显,移植瘤细胞Bel-2表达为（339．19±42．34）,与阴性对照组（492．31±36．19）比较,差异有统计学意义（P〈0．05）;Bax表达为（554．74±26．13）,与阴性对照组（397．48±18．36）比较,差异有高度统计学意义（P〈0．01）。结论：氧化苦参碱对人胃癌MGC-803细胞裸鼠移植瘤生长有一定的抑制作用。且其机制与下调细胞Bel-2的表达、上调Bax的表达,从而诱导肿瘤细胞凋亡有关。     

5-氨基乙酰丙酸介导的光动力学治疗胃癌的实验研究

目的探讨5-氨基乙酰丙酸(5-ALA)介导的光动力学对人胃癌细胞MGC-803的治疗作用.方法将不同浓度的5-ALA加入细胞培养基中,随之给予相同剂量的激光辐射;之后用固定浓度的5-ALA处理细胞,并给予不同剂量的激光辐射.MTT法测定细胞生存率.结果在相同的辐射剂量下,经0.25、0.5、1.0、2.0、4.0 mmol/L的5-ALA处理的细胞生存率分别为(70.07±5.37)%、(50.04±4.99)%、(34.53±5.30)%、(26.89±4.44)%和23.90%±2.80%,除2.0和4.0 mmol/L5-ALA两组间外,其余各组间具有显著性差异(F=266.39,P＜0.001).在相同的5-ALA的浓度下,辐射剂量为6.25、12.5、25.0、50.0、100 J/cm2的细胞生存率分别为(83.50±10.43)%、(67.96±9.23)%、(33.80±8.26)%、(23.31±5.98)%和(14.96±3.50)%,各组之间有显著性差异(F=226.31,P＜0.0001).而单用5-ALA处理细胞,对应于其浓度为0.25、0.5、1.0、2.0,和4.0 mmol/L时的细胞生存率分别为(96.46±6.72)%、(97.48±5.27)%、(98.33±6.67)%、(99.47±6.97)%和(95.66±7.72)%,各浓度之间无显著性差异(F=0.79,P=0.5383).单纯激光辐射,其剂量为6.25、12.5、25.0、50.0、100.0 J/cm2时的细胞生存率也无显著性差异(F=0.61,P=0.6551).结论在较低的浓度范围内,5-ALA介导的光动力学治疗对人胃癌MGC-803细胞的杀伤作用随着5-ALA浓度的增加而增加,在较高浓度时则存在饱和现象,杀伤力与光剂量成正比.单纯激光不能产生光动力效应,5-ALA本身对细胞无毒性作用.5-ALA介导的光动力学治疗是很有希望的胃癌治疗方法.     

Src激酶和p38激酶在乙酰肝素酶促进人胃癌细胞迁移和侵袭中的作用及相互关系

目的 探讨Src激酶和p38激酶在乙酰肝素酶促进人胃癌细胞迁移和侵袭中的作用及相互关系.方法 实验设正常对照组(细胞未作其他处理)、人乙酰肝素酶重组蛋白处理组(5、10 μg/ml)以及提前3 h加入Src激酶特异性抑制剂pp2(5 μmol/L)或p38激酶特异性抑制剂SB 203580(1 μmol/L)再加入人乙酰肝素酶重组蛋白(10 μg/ml)作用24 h组.利用划痕损伤实验和Transwell小室基质侵袭实验分别检测各处理组对人胃癌MGC-803细胞迁移和侵袭能力的影响;Western blot法检测各处理组对人胃癌MGC-803细胞、高表达乙酰肝素酶的人胃癌SGC-7901细胞和乙酰肝素酶表达被下调的SGC-7901-Heparanasel(-)细胞中Src激酶、p38激酶、磷酸化Src激酶(p-Src)和磷酸化p38激酶(p-p38)蛋白表达的影响.结果 与正常对照组比较,5和10 μg/ml人乙酰肝素酶重组蛋白均能明显增强人胃癌MGC-803细胞迁移和侵袭能力(P<0.05);与未加抑制剂的人乙酰肝素酶重组蛋白比较,抑制剂pp2和SB 203580均能削弱人乙酰肝素酶重组蛋白增强的人胃癌MGC-803细胞的迁移和基质侵袭能力(P<0.05).10 μg/ml人乙酰肝素酶重组蛋白促进人胃癌MGC-803细胞Src激酶和p38激酶的磷酸化,而SGC-7901-Heparanasel(-)细胞中磷酸化的Src激酶和p38激酶表达水平较SGC-7901细胞明显下调(P<0.01);抑制剂pp2和SB 203580对人胃癌SGC-7901细胞中乙酰肝素酶蛋白表达无明显影响;在人胃癌SGC-7901细胞和MGC-803细胞中,Src激酶的抑制剂pp2抑制磷酸化p38蛋白的表达,而p38激酶的抑制剂SB 203580对磷酸化Src蛋白表达无明显影响.结论 乙酰肝素酶可能通过促进Src激酶磷酸化或p38激酶的磷酸化或先促进Src激酶磷酸化再促进p38激酶的磷酸化,从而促进人胃癌细胞迁移和侵袭能力.乙酰肝素酶-Src激酶磷酸化-p38激酶磷酸化可能是人胃癌细胞内存在的与细胞迁移和侵袭有关的信号转导通路.     

1,25-二羟维生素D_3对人胃腺癌细胞增殖和细胞周期的影响

目的:探讨1,25-二羟维生素D3对人胃腺癌细胞增殖和细胞周期的影响。方法:1,25-二羟维生素D3作用于MGC-803细胞后,应用四甲基偶氮唑蓝(MTT)法测定细胞增殖能力、平板克隆试验测定细胞集落形成率、流式细胞仪测定细胞周期。结果:1,25-二羟维生素D3作用后胃腺癌细胞生长受抑制,细胞集落形成率明显下降(P<0.05);处理48 h后细胞周期出现向G0/G1期移行的特征性动力学改变。结论:1,25-二羟维生素D3对人胃腺癌细胞有抑制增殖、诱导分化作用。     

稳定过表达Cdx2基因的胃癌细胞株的建立

目的 建立稳定过表达Cdx2基因的胃癌细胞株。方法 使用阳离子脂质体分别将真核表达载体pCMV-Cdx2-HA或空载体pCMV-HA转染至人胃癌细胞MGC-803中,G418筛选出阳性克隆后扩大培养。RT-PCR和Western Blot技术检测各组胃癌细胞中Cdx2基因mRNA和蛋白的表达情况,将挑选出的稳定株命名为MGC-803/Cdx2细胞（转染组）和MGC-803/EV细胞（空载体组）;流式细胞仪检测MGC-803细胞（未转染组）、MGC-803/EV细胞和MGC-803/Cdx2细胞的细胞周期和凋亡情况。结果 成功筛选出稳定过表达Cdx2基因的MGC-803胃癌细胞,即MGC-803/Cdx2细胞;与MGC-803细胞和MGC-803/EV细胞比较,MGC-803/Cdx2细胞中Cdx2基因mRNA和蛋白的表达明显增加（P<0.05）,而且细胞周期G0/G1期比例和凋亡率也明显增加（P<0.05）。结论 成功构建了稳定过表达Cdx2基因的胃癌细胞株,而且Cdx2过表达使细胞周期停滞、凋亡增加。