Combination therapy of poly (ADP-ribose) polymerase inhibitor 3-aminobenzamide and gemcitabine shows strong antitumor activity in pancreatic cancer cells

BACKGROUND AND AIM: Poly (ADP-ribose) polymerase (PARP) inhibitors such as 3-aminobenzamide (3-ABA) enhance the in vitro cytotoxicity of DNA mono-functional alkylating agents such as radiation or chemotherapeutic agents. The aim of this study was to test an approach combining the PARP inhibitor 3-ABA with standard gemcitabine therapy in human pancreatic cancer cells. METHODS: Cell viability was determined by proliferation assay (XTT). Cell-cycle analysis (FACS), ELISA (M30 Apoptosense), Western blot for caspase 8 and PARP, and electron microscopy were used to identify apoptosis. Tumor growth and survival was assessed in nude mice by subcutaneously injected Capan-1 cells. In addition, Ki67 staining was performed on tumors for cell proliferation and in vivo apoptosis induction was measured by TUNEL assay and ELISA. RESULTS: Combination therapy of gemcitabine and 3-ABA suppressed tumor cell growth more than gemcitabine alone in XTT, FACS and ELISA analysis. CONCLUSION: This in vivo study demonstrated a significantly reduced tumor weight and increased survival up to 40 days after cell inoculation with combination therapy compared to animals treated with PBS, gemcitabine or 3-ABA alone. Furthermore, TUNEL assay revealed a significant apoptosis induction and reduced proliferation in the combination group.     

Antiangiogenic therapy for human pancreatic carcinoma xenografts in nude mice

AIM: To investigate the anti-tumor effects of antiangiogenic therapy (a combination of TNP-470, an antiangiogenic compound, with gemcitabine, an antimetabolite) on human pancreatic carcinoma xenografts and its mechanism. METHODS: A surgical orthotopic implantation (SOI) model was established by suturing small pieces of SW1990 pancreatic carcinoma into the tail of pancreas in nude male mice. Mice then received either single therapy (n = 24) or combined therapy (n = 32). Mice receiving single therapy were randomly divided into control group, G100 group receiving 100 mg/kg gemcitabine IP on d O, 3, 6 and 9 after transplantation, and T30 group receiving 30 mg/kg TNP-470 s.c on alternate days for 8 wk. Mice receiving combined therapy were randomly divided into control group, T15 group, G50 group and combination group (TNP-470 30 mg/kg and gemcitabine 50 mg/kg). Animals were killed 8 wk after transplantation. Transplanted tumors, liver, lymph node and peritoneum were removed. Weight of transplanted tumors, the T/C rate (the rate of mean treated tumor weight to mean control tumor weight), change of body weight, metastasis rate, and 9-wk survival rate were investigated. Tumor samples were taken from the control group, T30 group, G100 group and combination group. PCNA index (PI) and microvessel density (MVD) were investigated by immunohistochemical staining for PCNA and factor VIII, respectively. RESULTS: There was a significant inhibitory effect on primary tumor growth of pancreatic carcinoma in G100 group, compared to T30 group, whereas tumor metastasis was significantly inhibited in T30 group compared to G100 group. There was no significant improvement in survival rate in these two groups. No significant inhibitory effect on tumor growth and metastasis in T15 group and G50 group. However, significant anti-tumor and anti-metastatic effects were observed in the combination group with a significant improvement in survival rate. The inhibitory effect on tumor growth in combination group enhanced 2 times in comparison with G50 group and 5 times in comparison with T15 group. Moreover, 25% of the animals hearing tumors were cured by the combination therapy. The levels of MVD and PI were 14.50±5.93 and 0.41±0.02,12.38±1.60 and 0.30±0.07, 7.13±2.99 and 0.37±0.03, and 5.21±1.23 and 0.23±0.02 respectively in the control group, G100 group, T30 group and combination group. A significant inhibitory effect on PI level and MVD level was observed in G100 group and T30 group respectively whereas both MVD and PI levels were significantly inhibited in the combination group (P<0.05). CONCLUSION: Antiangiogenic therapy shows significant anti-tumor and anti-metastatic effects, and is helpful to reduce the dosage of cytotoxic drugs and the side effects. These effects are related to the antiangiogenic effect of TNP-470 and cytotoxic effect of gemcitabine.     

Cytochalasin D,a tropical fungal metabolite,inhibits CT26 tumor growth and angiogenesis

ObjectiveTo investigate whether cytochalasin D can induce antitumor activities in a tumor model.MethodsMurine CT26 colorectal carcinoma cells were cultured in vitro and cytochalasin D was used as a cytotoxic agent to detect its capabilities of inhibiting CT26 cell proliferation and inducing cell apoptosis by MTT and a TUNEL-based apoptosis assay. Murine CT26 tumor model was established to observe the tumor growth and survival time. Tumor tissues were used to detect the microvessel density by immunohistochemistry. In addition, alginate encapsulated tumor cell assay was used to quantify the tumor angiogenesis in vivo.ResultsCytochalasin D inhibited CT26 tumor cell proliferation in time and dose dependent manner and induced significant CT26 cell apoptosis, which almost reached the level induced by the positive control nuclease. The optimum effective dose of cytochalasin D for in vivo therapy was about 50 mg/kg. Cytochalasin D in vivo treatment significantly inhibited tumor growth and prolonged the survival times in CT26 tumor-bearing mice. The results of immunohistochemistry analysis and alginate encapsulation assay indicated that the cytochalasin D could effectively inhibited tumor angiogenesis.ConclusionsCytochalasin D inhibits CT26 tumor growth potentially through inhibition of cell proliferation, induction of cell apoptosis and suppression of tumor angiogenesis.     

Targeting hepatitis B virus antigens to dendritic cells by heat shock protein to improve DNA vaccine potency

AIM： To investigate a novel DNA vaccination based upon expression of the HBV e antigen fused to a heat shock protein （HSP） as a strategy to enhance DNA vaccine potency.
METHODS： A pCMV-HBeAg-HSP DNA vaccine and a control DNA vaccine were generated. Mice were immunized with these different construct. Immune responses were measured 2 wk after a second immunization by a T cell response assay, CTL cytotoxicity assay, and an antibody assay in C57BL/6 and BALB/c mice. CT26-HBeAg tumor cell challenge test in vivo was Performed in BALB/c mice to monitor anti-tumor immune responses.
RESULTS： In the mice immunized with pCMV-HBe-HSP DNA, superior CTL activity to target HBV-positive target cells was observed in comparison with mice immunized with pCMV-HBeAg （44% ± 5% vs 30% ± 6% in E： T 〉 50：1, P 〈 0,05）, ELISPOT assays showed a stronger T-cell response from mice immunized with pCMV-HBe- HSP than that from pCMV-HBeAg immunized animals when stimulated either with MHC class I or class Ⅱ epitopes derived from HBeAg （74% ± 9% vs 31% ± 6%, P 〈 0.01）. ELISA assays revealed an enhanced HBeAg antibody response from mice immunized with pCMV- HBe-HSP than from those immunized with pCMV-HBeAg. The lowest tumor incidence and the slowest tumor growth were observed in mice immunized with pCMV- HBe-HSP when challenged with CT26-HBeAg.
CONCLUSION： The results of this study demonstrate a broad enhancement of antigen-specific CD4^＋ helper,CD8^＋ cytotoxic T-cell, and B-cell responses by a novel DNA vaccination strategy. They also proved a stronger antigen-specific immune memory, which may be superior to currently described HBV DNA vaccination strategies for the treatment of chronic HBV infection.     

A DNA vaccine against extracellular domains 1-3 of flk-1 and its immune preventive and therapeutic effects against H22 tumor cell in vivo

AIM: To construct a DNA vaccine against extracellular domains 1-3 of fetal liver kinase-1(flk-1), and to investigate its preventive and therapeutic effect against H22 cell in vivo. METHODS: Flk-1 DNA vaccine was produced by cloning extracellular domains 1-3 of flk-1 and by inserting the cloned gene into pcDNA3.1(+). Fifteen mice were divided into 3 groups and inoculated by vaccine, plasmid and saline respectively to detect specific T lymphocyte response. Thirty Mice were equally divided into preventive group and therapeutic group. Preventive group was further divided into V,P,andS subgroups, namely immunized by vaccine,pcDNA3.1(+) and saline, respectively, and attacked by H22 cell. Therapeutical group was divided into 3 subgroups of V,P and S, and attacked by H22, then treated with vaccine, pcDNA3.1(+) and saline, respectively. The tumor size, tumor weight, mice survival time and tumor latency period were compared within these groups. Furthermore,intratumoral microvessel density (MVD) was assessed by immunohistochemistry. RESULTS: DNA vaccine pcDNA3.1(+)flk-1-domains 1-3 was successfully constructed and could raise specific CTL activity. In the preventive group and therapeutic group,tumor latency period and survival time were significantly longer in vaccine subgroup than that in P and S subgroups (P＜0.05);the tumor size, weight and MVD were significantly less in vaccine subgroup than that in P and S subgroups (P＜0.05). The survival time of therapeutic vaccine subgroup was significantly shorter than that of preventive vaccine subgroup (P＜0.05);the tumor size, and MVD of therapeutic vaccine subgroup were significantly greater than that of preventive vaccine subgroup (P＜0.05).CONCLUSION: DNA vaccine against flk-1 domains 1-3 can stimulate potent specific CTL activity; and has distinctive prophylactic effect on tumor H22, and also can inhibit the tumor growth in vivo. This vaccine may be used as an adjuvant therapy because it is less effective on detectable tumor.     

An effective vaccine against colon cancer in mice： Use of recombinant adenovirus interleukin-12 transduced dendritic cells

AIM： To investigate the effect of a vaccine with recombinant adenovirus interleukin-12 （AdVIL-12） transduced dendritic cells （DCs） against colon cancer in mice. METHODS： DCs and AdVIL-12 were incubated together at different time intervals and at different doses. Supernatant was collected and tested for IL-12 by enzyme-linked immunosorbent assay （ELISA）. In order to determine whether tumor cell lysate-pulsed （TP） AdVIL-12/DCs enhance therapeutic potential in the established tumor model, CT26 colon tumor cells were implanted subcutaneously （s.c.） in the midflank of naive BALB/c mice. Tumor-bearing mice were injected with a vaccination of CT26 TP AdVIL-12/DCs on d 3 and 10. As a protective colon tumor model, naive BALB/c mice were immunized s.c. in their abdomens with CT26 TP AdVIL-12/DCs twice at seven day intervals. After the immunization on d 7, the mice were challenged with a lethal dose of CT26 tumor cells and survival times were evaluated. Subsequently, cytotoxic T lymphocyte （CTL） activity and interferon gamma （IFNy） secretion was evaluated in the immunized mice, and assayed CTL ex vivo. RESULTS： Murine DCs were retrovirally transduced with AdVIL-12 efficiency, and the AdVIL-12 transduced DCs secreted a high level of IL-12 （AdVIL-12/DCs, 615.27 ± 42.3 pg/mL vs DCs, 46.32 ± 7.29 pg/mL, P 〈 0.05）. Vaccination with CT26 TP AdVIL-12/DCs could enhance anti-tumor immunity against CT26 colon tumor in murine therapeutic models （tumor volume on d 19：CT26 TP AdVIL-12/DCs 107 ± 42 mm^3 vs CT26 TP DCs 383± 65 mm^3, P 〈 0.05） and protective models. Moreover, the CT26 TP AdVIL-12/DC vaccination enhances tumor-specific CTL activity, producing high levels of IFN7 in immunized mice. Ex vivo primed T cells with AdVIL-12/DCs were able to induce more effective CTL activity than in primed T cells with CT26 TP/DCs （E：T = 100：1, 69.49% ± 6.11% specific lysis vs 37.44% ＋ 4.32% specific lysis, P 〈 0.05）.CONCLUSION： Vaccination with recombinant AdVIL-12 transduced DC p     

Heat-shocked tumor cell lysate-pulsed dendritic cells induce effective anti-tumor immune response in vivo

AIM:To study whether heat-shocked tumor cells couldenhance the effect of tumor cell lysate-pulsed dendriticcells(DCs)in evoking anti-tumor immune response invivo.METHODS:Mouse undifferentiated colon cancer cells(CT-26)were heated at 42℃ for 1h and then frozen-thawed.The bone marrow-derived DCs pulsed with heat-shocked CT-26 cell lysate(HSCT-26 DCs)were recruitedto immunize syngeneic na(?)ve BALB/c mice.The cytotoxicactivity of tumor specific cytotoxic T lymphocytes(CTLs)in mouse spleen was evaluated by IFN-enzyme-linkedimmunospot(ELISpot)and LDH release assay.Theimmunoprophylactic effects induced by HSCT-26 DCsin mouse colon cancer model were compared to thoseinduced by single CT-26 cell lysate-pulsed DCs(CT-26DCs)on tumor volume,peritoneal metastasis andsurvival time of the mice.RESULTS:Heat-treated CT-26 cells showed a higherhsp70 protein expression.Heat-shocked CT-26 cell lysatepulsing elevated the co-stimulatory and MHC-II moleculeexpression of bone marrow-derived DCs as well asinterleukin-12 p70 secretion.The IFN-γ secreting CTLsinduced by HSCT-26 DCs were significantly more thanthose induced by CT-26 DCs(P=0.002).The formerCTLs'specific cytotoxic activity was higher than the latterCTLs'at a serial E/T ratio of 10:1,20:1,and 40:1.Mousecolon cancer model showed that the tumor volumeof HSCT-26 DC vaccination group was smaller thanthat of CT-26 DC vaccination group on tumor volumethough there was no statistical difference between them (24 mm~3 vs 8 mm~3,P=0.480).The median survival timeof mice immunized with HSCT-26 DCs was longer thanthat of those immunized with CT-26 DCs(57 d vs 43 d,P=0.0384).CONCLUSION:Heat-shocked tumor cell lysate-pulsedDCs can evoke anti-tumor immune response in vivoeffectively and serve as a novel DC-based tumor vaccine.     

Immunotherapy of tumor with vaccine based on basic fibroblast growth factor-activated fibroblasts

Purpose

Cancer-associated fibroblasts play a key role in tumor progression. It is conceivable that the breaking of immune tolerance of “self-antigens” associated with tumor cells and tumor stromal is an attractive approach for tumor immunotherapy. To test this concept, we used basic fibroblast growth factor (bFGF) to activate normal fibroblasts and used these activated fibroblasts as one vaccine against tumor.

Methods

Normal fibroblasts were treated with bFGF; their expressions of a-SMA and FAP were assessed by Western blot. We immunized mice with bFGF-activated fibroblasts. Auto-antibodies were assessed by flow cytometric and Western blot analysis. The deposition of auto-antibodies within the tumor tissues was assessed. The inhibition of proliferation of tumor cells and fibroblasts by purified immunoglobulins was investigated. The anti-tumor effects of purified immunoglobulins and lymphocytes of immunized mice were assessed.

Results

The bFGF-activated fibroblasts were effective in affording protection from tumor onset, growth, and prolonging survival of tumor-bearing mice. The immunized sera exhibited positive staining for fibroblasts and tumor cells in FCAS and Western blot analysis. The purified immunoglobulins of immunized serum could inhibit the proliferation of tumor cells and fibroblasts in vitro and had the anti-tumor activity in vivo. There was the deposition of auto-antibodies within the tumor tissues. Adoptive transfer of lymphocytes of immunized mice revealed that cellular immune response is also involved. The anti-tumor activity could be abrogated by the depletion of CD4⁺, CD8⁺ T lymphocytes and NK cells.

Conclusions

In summary, bFGF-activated fibroblasts could induce an autoimmune response which was simultaneously against both cancer-associated fibroblasts and tumor cells in a cross-reaction.     

Clobenpropit enhances anti-tumor effect of gemcitabine in pancreatic cancer

AIM: To evaluate the anti-tumor effect of clobenpropit, which is a specific H₃ antagonist and H₄ agonist, in combination with gemcitabine in a pancreatic cancer cell line.METHODS: Three kinds of human pancreatic cancer cell lines (Panc-1, MiaPaCa-2, and AsPC-1) were used in this study. Expression of H₃ and H₄ receptors in pancreatic cancer cells was identified with Western blotting. Effects of clobenpropit on cell proliferation, migration and apoptosis were evaluated. Alteration of epithelial and mesenchymal markers after administration of clobenpropit was analyzed. An in vivo study with a Panc-1 xenograft mouse model was also performed.RESULTS: H₄ receptors were present as 2 subunits in human pancreatic cancer cells, while there was no expression of H₃ receptor. Clobenpropit inhibited cell migration and increased apoptosis of pancreatic cancer cells in combination with gemcitabine. Clobenpropit up-regulated E-cadherin, but down-regulated vimentin and matrix metalloproteinase 9 in real-time polymerase chain reaction. Also, clobenpropit inhibited tumor growth (gemcitabine 294 ± 46 mg vs combination 154 ± 54 mg, P = 0.02) and enhanced apoptosis in combination with gemcitabine (control 2.5%, gemcitabine 25.8%, clobenpropit 9.7% and combination 40.9%, P = 0.001) by up-regulation of E-cadherin and down-regulation of Zeb1 in Panc-1 xenograft mouse.CONCLUSION: Clobenpropit enhanced the anti-tumor effect of gemcitabine in pancreatic cancer cells through inhibition of the epithelial-mesenchymal transition process.     

西罗莫司对人肝癌裸鼠肝脏移植瘤生长的影响

目的 探讨西罗萸司(SRL)对人肝癌裸鼠肝脏移植瘤生长的影响.方法 建立人肝癌裸鼠肝脏移植瘤模型,使用SRL、他克莫司(FK506)进行干预治疗,采用免疫组织化学方法和图像分析技术检测移植瘤血管内皮细胞生长因子、增殖细胞核抗原的表达和微血管密度,原位末端标记法检测肿瘤细胞凋亡情况.统计学处理采用方差分析或t检验.结果 (1)SRL、FK506组和对照组移植瘤质量分别为(352±38)mg、(683±53)mg、(675±45)mg;SRL组移植瘤质量较对照组明显减少(t=10.378,P<0.01);FK506组和对照组比较无明显差异(P>0.05).(2)SRL组移植瘤血管内皮细胞生长因子和增殖细胞核抗原的表达较对照组明显下凋亡(f值分别为5.753和5.296,P<0.05),FK506组和对照组比较无明显差异(P>0.05).(3)SRL组移植瘤微血管密度较对照组明显减少(t=8.637,P<0.01);FK506组和对照组相比无明显变化(P>0.05).(4)SRL组移植瘤凋亡指数明显高于对照组(t=11.518,P<0.05);FK506对移植瘤凋亡指数无明显影响(P>0.05). 结论 SRL可通过减少肿瘤血管形成、阻I卜肿瘤增殖、诱导肿瘤细胞凋亡抑制肝癌的生长.     

前列腺癌树突细胞瘤苗的制备及其应用

目的 构建前列腺癌树突细胞（DC）瘤苗,并探讨其体内外抗前列腺癌的作用。方法 分离C57BL／6小鼠骨髓前体细胞制备DC,光镜下观察DC的形态学特征,混合淋巴细胞试验、辣根过氧化物酶（HRP）吞噬试验观察DC的生物学特性。经RM-1前列腺癌细胞裂解产物致敏构建DC瘤苗,将DC瘤苗皮下注射于18只前列腺癌模型小鼠。结果成熟DC突起多而长,胞内囊泡少,刺激T细胞增殖能力强;DC瘤苗分泌IL-12能力增强;小鼠应用DC瘤苗后,其脾脏T细胞对RM-1细胞具有特异性杀伤作用;荷瘤小鼠肿瘤生长缓慢,坏死明显,瘤体内及肿瘤周围有大量炎细胞浸润。结论小鼠骨髓单核细胞在粒细胞／巨细胞集落刺激因子（GM-CSF）和IL-4诱导下可转化为DC。RM-1前列腺癌细胞裂解物致敏构建的DC瘤苗能诱导T细胞对RM-1细胞产生特异性杀伤作用,且能分泌更多的IL-12,可用于前列腺癌的免疫治疗。     

白藜芦醇和吉西他滨联合用药对人胰腺癌细胞作用的研究

背景：吉西他滨是治疗进展期胰腺癌的一线化疗药物,单独用药临床效果欠佳。白藜芦醇为脱嘌呤脱嘧啶核酸内切酶1／氧化还原因子－1（APEl／Ref-1）的氧化还原功能抑制剂,具有抑制恶性肿瘤生长的特性．可能在胰腺癌的预防和治疗中发挥重要作用。目的：检测白藜芦醇和吉西他滨联合用药对人胰腺癌细胞株生长和凋亡的影响．并进一步探讨发挥该作用的分子机制。方法：将胰腺癌细胞株SWl990和BxPc-3分为4组：溶剂对照组、吉西他滨组、白藜芦醇组和联合用药组。采用CCK-8法和流式细胞术分别检测细胞增殖和凋亡．以蛋白质印迹法检测APE1／Ref-1蛋白的表达。结果：作用于SWl990和BxPc-3细胞24h、48h和72h后．与溶剂对照组相比,三组用药组的细胞存活率均明显降低;作用于SWl990和BxPc-3细胞48h后,与溶剂对照组相比,三组用药组的细胞凋亡率均明显增加：联合用药组对细胞增殖和凋亡的影响均强于两组单独用药组。与空白对照组相比．吉西他滨组SWl990和BxPc－3细胞APEl／Ref-1蛋白表达均明显增加。结论：白藜芦醇和吉西他滨联合用药可明显加强对胰腺癌细胞增殖和凋亡的影响．白藜芦醇可能通1寸抑制APEl,Ref-1蛋白的氧化还原功能而增加胰腺痛细胞对吉西他滨的敏感十牛．     

Enhanced efficacy of herpes simplex virus mutant HF10 combined with paclitaxel in peritoneal cancer dissemination models

BACKGROUND/AIMS: Oncolytic viral therapy is used worldwide. Many genetically engineered viruses have been evaluated for their potential as a new therapeutic agent for cancer. HF10, herpes simplex virus (HSV) type-1 clone, has remarkable anti-tumor effects, based on our previous research. In this study, we investigated the ability of HF10 to infect and lyse murine colon cancer cells, CT26, in vitro, and tested its efficacy in an immuno-competent animal model of colorectal cancer. Further, we attempted to evaluate HF10/paclitaxel combination therapy. METHODOLOGY: In vitro, viral replication and cytotoxicity of HF10 against CT26 was observed. In vivo, BALB/c mice harboring carcinomatous peritonitis of CT26 cells were treated with HF10, paclitaxel or HF10 combined with paclitaxel. RESULTS: HF10 is effective for peritoneal dissemination without ascites. The combination of HF10 and paclitaxel prolonged survival of mice bearing carcinomatous dissemination of CT26 compared with the controls, HF10 alone and paclitaxel alone. Paclitaxel did not suppress viral replication and cytotoxicity of HF10. CONCLUSIONS: These results indicate that the combination of HF10 and paclitaxel had a remarkable effect as a cancer therapy and this method is applicable to almost all advanced cancers. This new combination therapy is a potentially epoch-making cancer therapy.     

人参皂苷Rg3对小鼠结肠癌原发瘤切除后肝转移瘤生长的抑制作用

目的:探讨人参皂苷Rg3对小鼠原发瘤切除后肝内转移瘤生长的荧光成像及血管生成的影响,阐明人参皂苷Rg3抑制原发瘤切除促进转移瘤生长的内在机制.方法:慢病毒转染建立稳定表达绿色荧光蛋白(green fluorescent protein,GFP)基因的BALB/c小鼠结肠腺癌细胞株(BALB/c micecolon adenocarcinoma cell line,CT-26),用细胞悬液法构建结肠癌肝转移瘤模型,分为原发瘤切除组、原发瘤未切除组、人参皂苷Rg3组.采用切除原发瘤及人参皂苷Rg3治疗10d,通过小动物活体成像系统观察肝转移瘤的生长情况.应用组织切片苏木素-伊红染色法,观察肿瘤转移灶情况.SP免疫组织化学法检测转移瘤MVD及细胞增殖,TUNEL技术检测转移瘤细胞凋亡.结果:应用慢病毒转染获得稳定表达高强度绿色荧光的CT-26-GFP细胞株.结肠癌肝转移模型治疗结束后,用波长470nm的蓝光激发,通过荧光活体成像系统观察剖离肝脏转移灶发出绿色荧光.原发瘤切除后,人参皂苷Rg3组平均肝转移灶荧光值较原发瘤未切除组及原发瘤切除组有明显的下降(314.17±54.23,388.82±25.97,427.18±44.31);人参皂苷Rg3组、原发瘤未切除组和原发瘤切除组转移瘤发生率分别为40%,50%,100%;平均肝脏质量分别为2.92g±0.60g,3.80g±0.33g,3.98g±0.52g;转移瘤血管密度分别为27.10±3.41,42.60±8.42,62.40±5.08;转移瘤细胞Ki67的表达分别为34.70±6.46,54.30±8.98,65.20±3.82;转移瘤细胞凋亡指数分别为28.37±3.86,12.50±2.99,9.90±2.88.结论:稳定表达绿色荧光蛋白的CT-26-GFP细胞系及其动物模型可以为原发瘤切除研究提供理想的实验材料,应用小动物活体成像系统能够客观定量评价肿瘤在小鼠肝脏的生长情况.人参皂苷Rg3明显抑制小鼠原发瘤切除后肝内转移瘤的生长,明显抑制转移瘤的血管生成及细胞增殖,促进细胞凋亡.     

Treatment of metastatic colorectal carcinomas by systemic inhibition of vascular endothelial growth factor signaling in mice

AIM: Tumor angiogenesis has been shown to be promoted by vascular endothelial growth factor (VEGF) via stimulating endothelial cell proliferation, migration, and survival. Blockade of VEGF signaling by different means has been demonstrated to result in reduced tumor growth and suppression of tumor angiogenesis in distinct tumor entities. Here, we tested a recombinant adenovirus, AdsFIt1-3, that encodes an antagonistically acting fragment of the VEGF receptor 1 (Flt-1), for systemic antitumor effects in pre-established subcutaneous CRC tumors in mice. METHODS: Murine colorectal carcinoma cells (CT26) were inoculated subcutaneously into Balb/c mice for in vivo studies. Tumor size and survival were determined. 293 cell line was used for propagation of the adenoviral vectors. Human lung cancer line A549 and human umbilical vein endothelial cells were transfected for in vitro experiments. RESULTS: Infection of tumor cells with AdsFlt1-3 resulted in protein secretion into cell supernatant, demonstrating correct vector function. As expected, the secreted sFlt1-3 protein had no direct effect on CT26 tumor cell proliferation in vitro, but endothelial cell function was inhibited by about 46% as compared to the AdLacZ control in a tube formation assay. When AdsFlt1-3 (5×109 PFU/animal) was applied to tumor bearing mice, we found a tumor inhibition by 72% at d 12 after treatment initiation. In spite of these antitumoral effects, the survival time was not improved. According to reduced intratumoral microvessel density in AdsFIt1-3-treated mice, the antitumor mechanism can be attributed to angiostatic vector effects. We did not detect increased systemic VEGF levels after AdsFlt1-3 treatment and liver toxicity was low as judged by serum alanine aminotransferase determination. CONCLUSION: In this study we confirmed the value of a systemic administration of AdsFIt1-3 to block VEGF signaling as antitumor therapy in an experimental metastatic colorectal carcinoma model in mice.     

Effect of 2-（8-hydroxy-6-methoxy- 1-oxo- 1H-2-benzopyran-3yl） propionic acid in combination with carboplatin on gastric carcinoma growth in vivo

AIM： To investigate the effects of 2-（8-hydroxy-6- methoxy-l-oxo-lH-2-benzopyran-3-yl） propionic acid （NM-3） alone and in combination with carboplatin on tumor growth and apoptosis in mouse models of human gastric cancer constructed by subcutaneous implantation of histologically intact tumor tissue.
METHODS： Human gastric cancer SGC-7901 tissues were implanted into the dorsal subcutis of nude mice. One week after tumors reached to a volume of 50-100 mm3 for around 1 wk, these mice were randomly divided into 8 groups （n = 10）. NM-3 was injected peritoneally at the dose of 10 mg/kg, 20 mg/kg or 40 mg/kg every other day for 5 wk, combined with carboplatin （5 mg/kg） every third day for 4 wk. As controls of combined treatment, another 4 groups of mice were injected with either NM-3 at 10 mg/kg, 20 mg/kg or 40 mg/kg, or with carboplatin alone （5 mg/kg）. The control mice received normal saline. Tumor weight, tumor growth inhibition （TGI）, and intratumoral microvessel density （MVD） were evaluated. Apoptosis of human gastric cancer was detected by TUNEL method and flow o/tometry analysis, respectively.
RESULTS： The mean tumor volume （692.40 ± 58.43 mm3, 548.30 ± 66.02 mm3, 382.13 ± 43.52 mm3） after treatment with carboplatin combined NM-3 at the dose of 10 mg/kg, 20 mg/kg or 40 mg/kg was lower than that after treatment with either NM-3 at the dose of 10 mg/kg, 20 mg/kg or 40 mg/kg or with carboplatin alone. Compared with the normal saline group, NM-3 administered at 10 mg/kg, 20 mg/kg or 40 mg/kg significantly reduced the tumor weight in these groups （P 〈 0.05）. Carboplatin used alone at 5 mg/kg showed minimal effects. But NM-3 in combination with carboplatin had greater effects of tumor weight than either NM-3 or carboplatin alone. NM-3 alone at the dose 10 mg/kg or in combination with carboplatin had no obvious effects on body changes. Two mice died of diarrhea in each of the two groups treated with 40 mg/kg NM-3 or with 40 mg/kg NM-3 in combination with carboplatin. A     

Anti-cancer effects of COX-2 inhibitors and their correlation with angiogenesis and invasion in gastric cancer

AIM: To observe the anti-cancer effects of COX-2 inhibitors and investigate the relationship between COX-2 inhibitors and angiogenesis, infiltration or metastasis in SGC7901 cancer xenografts. METHODS: Thirty athymic mice xenograft models with human stomach cancer cell SGC7901 were established and divided randomly into 3 groups of 10 each. Sulindac, one non-specific COX inhibitor belonging to non-steroidal anti-inflammatory drugs (a series of COX inhibitors known as NSAIDs) and celecoxib, one selective COX-2 inhibitor (known as SCIs) were orally administered to mice of treatment groups. Immunohistochemistry was used to examine the expression of PCNA, CD44v6 and microvessel density (MVD). Apoptosis was detected by using TUNEL assay. RESULTS: Tumors in sulindac and celecoxib groups were significantly smaller than those in control group from the second week after drug administration (P<0.01). In treatment group, the cell proliferation index was lower (P<0.05) and apoptosis index was higher (P<0.05) than those in control groups. Compared with the controls, microvessel density was reduced (P<0.01) and expression of CD44v6 on tumor cells was weakened (P<0.05) in treatment groups. CONCLUSION: COX-2 inhibitors have anticancer effects on gastric cancer. They play important roles in angiogenesis and infiltration or metastasis of stomach carcinoma. The anticancer effects of COX-2 inhibitors may include inducing apoptosis, suppressing proliferation, reducing angiogenesis and weakening invasiveness.     

Role of inducible nitric oxide synthase expression in aberrant crypt foci－adenoma－carcinoma sequence

AIM: To investigate the expression of inducible nitric oxidesynthase (iNOS) in aberrant crypt foci (ACF) -adenomacarcinoma sequence and its relation with tumor cellapoptosis, proliferation and angiogenesis. METHODS: The expression of iNOS, proliferating cellnuclear antigen (PCNA) and microvessel density (MVD) indifferent stages of colorectal cancer were studied by immunohistochemical method from 30 normal tissues, 30nonhyperplastic ACF, 30 hyperplastic ACF, 30 dysplastic ACF,30 adenomas and 60 carcinomas. The apoptotic cells were detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method using an Apop Tag in situ detection kit. RESULTS: The immunoreactivity of iNOS significantly increased in the transition from hyperplastic ACF to dysplastic ACF. This transition was associated with a significant decrease in the apoptotic index (AI) (0.73+0.37 vs0.61±0.35, P＜0.05)and significant increases in the PCNA labeling index (LI)(27.3+2.80 vs 40.3+3.11, P＜0.01) and microvessel density (MVD) (55±11.5 vs 70±13.2, P＜0.01). The expression of iNOS was in low levels and positively correlated with PCNALI (r=0.812, P＜0.01) and MVD (r=0.863, P＜0.01) during transition from normal mucosa to nonhyperplastic ACF and hyperplastic ACF. The expression of iNOS was in high levels and positively correlated with AI (r=0.901, P＜0.01) after transition from hyperplastic ACF to dysplastic ACF, adenoma and carcinoma. CONCLUSION: The results suggest that the transition from hyperplastic ACF to dysplastic ACF may be a crucial step in the ACF-adenoma-carcinoma sequence, in which iNOS plays an important role by regulating tumor cell apoptosis,proliferation and angiogenesis.