榄香烯对裸鼠胃癌原位移植瘤血管生成的抑制作用

 目的 观察榄香烯对裸鼠胃癌原位移植瘤生长和血管生成的抑制作用。 方法 采用裸小鼠胃癌原位移植模型,随机分为0.9%氯化钠溶液(NS)组、5-Fu组、榄香烯组和联合组 ,腹腔注射给药。比较各组移植瘤瘤重的差异;免疫组织化学法检测肿瘤微血管密度 (Microvessel Density,MVD) 和VEGF、p53蛋白表达,RT-PCR法检测VEGF mRNA表达。 结果 联合组裸鼠胃癌移植瘤的瘤重显著低于NS组(P＜0.05);榄香烯组、联合组瘤组织MVD、VEGF蛋 白、p53蛋白及VEGF mRNA表达亦明显低于NS组(P＜0.05);各组移植瘤的瘤重与瘤组织MVD呈正 相关(r=0.669,P＜0.01)。 结论 榄香烯能抑制裸鼠胃癌原位移植瘤生长和血管生成,其机制可能与抑制裸鼠胃癌组织VEGF和突 变型p53的表达有关。     

豆蔻提取物对人胃癌裸鼠移植瘤生长及血管生成的影响

[目的]观察豆蔻提取物对人胃癌细胞裸鼠移植瘤的生长和对肿瘤血管生成的影响。[方法]建立人胃癌SGC-7901细胞裸鼠皮下移植瘤模型（n=24）,随机分成4组（n=6）,对照组、豆蔻组、5-Fu组、联合组,各组按设计剂量给药。测定移植瘤体积、瘤重及抑瘤率;用免疫组化法检测各组移植瘤瘤体中血管内皮生长因子（VEGF）和微血管密度（MVD）的表达情况。[结果]豆蔻组、5-Fu组、联合组的瘤重和瘤体积明显低于对照组（P〈0.05）,3组抑瘤率分别为45.83%、66.96%和77.28%。联合组中VEGF表达率和MVD计数明显低于对照组（P〈0.05）。[结论]豆蔻提取物可抑制胃癌移植瘤的生长,与5-Fu联合应用具有协同作用,其作用机制可能与下调VEGF的表达、减少MVD有关。     

紫杉醇节律化疗联合EGCG抑制胃癌生长和肿瘤血管生成的实验研究

目的:探讨低剂量紫杉醇联合表没食子儿茶素没食子酸酯(EGCG)对胃癌肿瘤血管生成的影响,并观察其抑瘤效果。方法:建立裸鼠人胃癌移植瘤模型,分别给予0.9%NaCl溶液、最大耐受剂量(MTD)紫杉醇、低剂量紫杉醇、EGCG及低剂量紫杉醇联合EGCG腹腔注射,观察肿瘤生长情况。免疫组化染色,测定CD31和血管内皮生长因子(VEGF)表达情况。结果:对照组肿瘤生长迅速,其他治疗组肿瘤生长都受到了抑制,联合治疗组抑瘤效果最明显,各组比较差异有统计学意义,P<0.05。与对照组及MTD组相比,低剂量紫杉醇组肿瘤组织内的微血管密度(MVD)及VEGF表达均下降,合用EGCG后,MVD和VEGF表达下降更明显,P<0.05。结论:低剂量紫杉醇化疗能够有效抑制裸鼠胃癌移植瘤的生长及微血管的形成,与EGCG联合应用时效果增强。     

胃癌细胞和组织块原位移植模型的建立及评价

[目的]采用两种方法建立胃癌裸鼠原位移植模型，并对两种模型进行评价。[方法]将胃癌肿瘤细胞悬液、胃癌裸鼠皮下瘤块采用OB胶粘贴法种植于裸鼠胃壁，形成原位移植瘤，观察和比较两种方法所建立的模型肿瘤移植成功率和自发转移的发生率。常规HE染色，观察胃癌原位移植瘤、胃癌淋巴结转移和肝转移的病理切片。免疫组化法检测胃癌原位移植瘤的MVD和VEGF的表达。[结果]细胞悬液种植的原位胃癌成瘤率为60％，淋巴结转移率和肝转移发生率仅为55．6％和33．3％；皮下组织块移植OB胶粘贴法的原位成瘤率100％，淋巴结转移率和肝转移发生率为93.3％和80％。皮下瘤块的原位移植瘤中MVD值和VEGF的表达高于细胞悬液法鼠移植瘤中MVD和VEGF的表达。[结论]两种原位移植和转移模型均具有人胃癌自然生长过程的特点，以胃癌裸鼠皮下组织块OB胶粘贴法为优，且肿瘤血管新生的能力较强。     

沉默乙酰肝素酶基因对胃癌生物学行为的影响

目的 探讨乙酰肝素酶(HPA)沉默对人胃癌裸鼠移植瘤生长、转移和血管形成的影响.方法 利用人胃癌SGC-7901细胞和HPA被沉默的SGC-7901-HPA-细胞,分别建立6只裸鼠皮下移植瘤模型,观察成瘤的时间、肿瘤生长速度和体积.应用逆转录聚合酶链反应(RT-PCR)和Western blot方法分别检测皮下移植瘤组织中HPA mRNA和蛋白的表达,应用免疫组织化学SP法检测皮下移植瘤组织的微血管密度(MVD).将皮下移植瘤细胞分别注射入6只裸鼠腹腔,建立腹腔转移瘤,并观察成瘤情况.结果 SGC-7901细胞和SGC-7901-HPA-细胞在裸鼠皮下均能生长出移植瘤,分别在接种后第4天后和第7天后出现肉眼可见的肿瘤,接种SGC-7901-HPA-细胞的裸鼠移植瘤生长较慢,MVD为(11.35±1.94)个/高倍视野,明显低于接种SGC-7901细胞组[(20.69±1.20)个/高倍视野,P＜0.05].接种SGC-7901-HPA-细胞与接种SGC-7901细胞的裸鼠皮下移植瘤组织相比,HPA mRNA和蛋白的表达均降低.由SGC-7901细胞皮下移植瘤组织建立腹腔转移瘤的裸鼠,有3只成瘤,在肝脏、大网膜、肠系膜、右肾形成了4处转移灶,且体积较大.而接种SGC-7901-HPA-细胞皮下移植瘤组织的裸鼠,仅有1只在肝脏和右肾形成了转移灶,而且瘤体较小.结论 HPA沉默后抑制了人胃癌在裸鼠体内的生长、转移和血管形成,HPA有可能成为预防和治疗胃癌的一个新靶H点.     

siRNA 抑制胃腺癌VEGF2C 表达和淋巴管生成

 目的　研究瘤内注射VEGF2C siRNA 抑制胃癌移植瘤VEGF2C 表达和肿瘤淋巴管生成的有效 性。方法　建立裸鼠胃癌皮下移植瘤模型随机分为4 组:VEGF2C siRNA 脂质体混合液组、单脂质体 组、单siRNA 组和PBS 组,对肿瘤进行原位注射干预,记录各实验组肿瘤体积变化,免疫组织化学法检 测各实验组肿瘤组织VEGF2C 的表达,并通过抗人CD31 和抗人L YVE21 单克隆抗体检测瘤体内血管 和淋巴管生成情况。结果　免疫组化显示干扰组肿瘤细胞VEGF2C 染色减弱,和对照组相比VEGF2C 表达下调68. 3 %( P < 0. 01) ,而胃癌组织中淋巴管密度(LVD) 值干预组和对照组分别为3. 2 ±1. 3 、9. 8 ± 2. 7 ,VEGF2C siRNA 干预组LVD 值下降至对照组的32. 7 %( P < 0. 01) ,而MVD 值无明显差异( P > 0. 05) 。结论　瘤内注射VEGF2C siRNA 能显著下调肿瘤组织内VEGF2C 的表达,有效抑制肿瘤生长 和瘤内淋巴管生成,而对肿瘤血管生成无影响。     

TL对人胰腺癌细胞裸鼠移植瘤的治疗作用及抑制血管生成的研究

目的：探讨雷公藤内酯醇（TL）对人胰腺癌细胞SW1990移植瘤的生长及新生血管生成的抑制作用。方法：通过人胰腺癌裸鼠皮下移植实验，观察不同剂量TL对移植瘤生长抑制作用；应用免疫组化和RT-PCR研究裸鼠移植瘤组织VEGF表达变化，计算肿瘤组织微血管密度（MVD）。结果：各实验组（TL0．125、0．25和0．5mg·^-1kg·day^-1）抑瘤率分别达到66．16％、78．14％和89．92％，与对照组相比，肿瘤生长明显受抑，并具有剂量和时间依赖性。对照组和各实验纽瘤组织MVD分别为36．25±8．64、22．75±6．67、17．65±7．11和9．87±3．34（P〈0．01）；TL抑制移植瘤VEGF基因和蛋白表达．且VEGF基因下调与MVD的减少具有相关性（r=0．7424，P〈0．01）．结论：TL具有显著的抗胰腺癌移植瘤作用．其机制可能与抑制肿瘤新生血管生成有关。     

人巨噬细胞金属弹性蛋白酶对人胃癌细胞COX-2和VEGF体内表达的影响

目的：探讨体内人巨噬细胞金属弹性蛋白酶（HME）对人胃癌细胞环氧合酶-2和血管内皮生长因子（VEGF）表达的影响。方法：选取BALB/c nu/nu裸鼠24只构建人胃癌细胞SCG-7901裸鼠皮下移植模型,随机分为对照组和HME干预组,其中HME干预剂量分别为0.2mg/kg、0.4mg/kg、0.8mg/kg,对照组给予等体积0.9%氯化钠。干预6周后处死动物,测量鼠重、瘤重、肿瘤大小,计算抑瘤率;采用Western blot和免疫组织化学方法检测移植瘤组织中COX-2和VEGF的表达;CD34标记血管内皮细胞计数肿瘤微血管密度（MVD）。结果：与对照组相比各剂量组HME均能明显抑制皮下移植瘤生长（ P <0.05）;且在HME各剂量组中0.8mg/kg组抑瘤作用最明显。HME能明显抑制移植瘤组织中COX-2和VEGF的表达,并明显降低肿瘤MVD值（ P <0.05）。结论：HME通过抑制肿瘤微血管形成来抑制肿瘤的生长;HME抑瘤作用具有剂量依赖性。     

人参皂苷Rg3联合三氧化二砷抑制乳腺癌移植瘤生长及其新生血管形成的研究

目的探讨人参皂苷Rg3(简称Rg3)联合三氧化二砷(As2O3)对裸鼠人乳腺癌移植瘤模型中肿瘤生长及新生血管密度的影响。方法右前肢腋窝皮下移植人乳腺癌MCF-7细胞株的雌性裸鼠28只,随机分成4组:①联合用药组即Rg3(12mg/kg.d)+As2O3(45μg/kg.d);②Rg3组(12mg/kg.d);③三氧化二砷组(45μg/kg.d);④对照组(0.5m l/d)。自肿瘤接种第5天开始,Rg3隔日灌胃,共25次;三氧化二砷腹腔内注射,每日1次,共35次,期间观察裸鼠的生存质量。停药1周后,脱颈处死裸鼠,检测肿瘤的重量,并计数肿瘤内微血管密度(MVD)。结果 Rg3组、三氧化二砷组、联合用药组对裸鼠人乳腺癌移植肿瘤生长的抑制作用明显,联合用药组抑制肿瘤生长的作用比单一用药组更强,联合用药组MVD明显低于三氧化二砷组及对照组。结论 Rg3与三氧化二砷联合应用具有协同作用,可明显抑制乳腺癌新生血管形成,降低乳腺癌组织内的MVD,进而抑制裸鼠乳腺癌移植瘤的生长,同时降低三氧化二砷的毒副反应。     

人参皂苷Rg3联合三氧化二砷抑制乳腺癌移植瘤生长及其新生血管形成的研究

目的探讨人参皂苷Rg3（简称Rg3）联合三氧化二砷（As2O3）对裸鼠人乳腺癌移植瘤模型中肿瘤生长及新生血管密度的影响。方法右前肢腋窝皮下移植人乳腺癌MCF-7细胞株的雌性裸鼠28只,随机分成4组：①联合用药组即Rg3（12mg/kg.d）＋As2O3（45μg/kg.d）;②Rg3组（12mg/kg.d）;③三氧化二砷组（45μg/kg.d）;④对照组（0.5m l/d）。自肿瘤接种第5天开始,Rg3隔日灌胃,共25次;三氧化二砷腹腔内注射,每日1次,共35次,期间观察裸鼠的生存质量。停药1周后,脱颈处死裸鼠,检测肿瘤的重量,并计数肿瘤内微血管密度（MVD）。结果 Rg3组、三氧化二砷组、联合用药组对裸鼠人乳腺癌移植肿瘤生长的抑制作用明显,联合用药组抑制肿瘤生长的作用比单一用药组更强,联合用药组MVD明显低于三氧化二砷组及对照组。结论 Rg3与三氧化二砷联合应用具有协同作用,可明显抑制乳腺癌新生血管形成,降低乳腺癌组织内的MVD,进而抑制裸鼠乳腺癌移植瘤的生长,同时降低三氧化二砷的毒副反应。     

A small interfering CD147-targeting RNA inhibited the proliferation, invasiveness, and metastatic activity of malignant melanoma

CD147 plays a critical role in the invasive and metastatic activity of malignant melanoma cells by stimulating the surrounding fibroblasts to express matrix metalloproteinases and vascular endothelial growth factor. We developed a system that blocks CD147 in the human malignant melanoma cell line, A375, using RNA interference. By transfecting melanoma cells with the small interfering RNA (siRNA) that targets human CD147, we were able to establish two stable clones in which CD147 expression was significantly down-regulated. This resulted in the decreased proliferation and invasion of A375 cells in vitro. CD147 siRNA also down-regulated the expression of vascular endothelial growth factor in these cells and reduced the migration of vascular endothelial cells. The reduction in the CD147 level suppressed the size of s.c. tumors and the microvessel density in an A375 s.c. nude mouse xenograft model. In addition, the in vivo metastatic potential of A375 cells transfected with CD147 siRNA was suppressed in a nude mouse model of pulmonary metastasis.     

Treatment for malignant pleural effusion of human lung adenocarcinoma by inhibition of vascular endothelial growth factor receptor tyrosine kinase phosphorylation.

Malignant pleural effusion (PE) is associated with advanced human lung cancer. We found recently, using a nude mouse model, that vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is responsible for PE induced by non-small cell human lung carcinoma cells. The purpose of this study was to determine the therapeutic potential of a VEGF/VPF receptor tyrosine kinase phosphorylation inhibitor, PTK 787, against PE formed by human lung adenocarcinoma (PC14PE6) cells. PTK 787 did not affect the in vitro proliferation of PC14PE6 cells, whereas it specifically inhibited proliferation of human dermal microvascular endothelial cells stimulated by VEGF/VPF. A specific platelet-derived growth factor receptor tyrosine kinase inhibitor, CGP57148 (used as a control because PTK 787 also inhibits platelet-derived growth factor receptor tyrosine kinases), had no effect on proliferation of PC14PE6 or human dermal microvascular endothelial cells. i.v. injection of PC14PE6 cells into nude mice produced lung lesions and a large volume of PE containing a high level of VEGF/VPF. Oral treatment with CGP57148 had no effect on PE or lung metastasis. In contrast, oral treatment with PTK 787 significantly reduced the formation of PE but not the number of lung lesions. Furthermore, treatment with PTK 787 significantly suppressed vascular hyperpermeability of PE-bearing mice but did not affect the VEGF/VPF level in PE or expression of VEGF/VPF protein and mRNA in the lung tumors of PC14PE6 cells in vivo. These findings indicate that PTK 787 reduced PE formation mainly by inhibiting vascular permeability, suggesting that this VEGF/VPF receptor tyrosine kinase inhibitor could be useful for the control of malignant PE.     

EGCG对胃癌血管新生中VEGF信号通路的多靶点作用

目的：探讨EGCG对胃癌血管生成抑制作用及其信号通路。方法：建立裸鼠异位胃癌模型,经腹腔注射EGCG,检测肿瘤生长及肿瘤组织微血管密度;不同浓度EGCG处理胃癌细胞24 h,检测胃癌VEGF蛋白和mRNA表达及VEGF分泌;同时不同浓度EGCG处理脐静脉内皮细胞,检测内皮细胞生长、迁移和体外小管形成。结果：EGCG显著抑制胃癌生长和肿瘤血管生成,平均肿瘤抑制率60.4%;EGCG显著抑制胃癌VEGF蛋白、mRNA表达和VEGF分泌;EGCG时间和剂量依赖性地抑制VEGF诱导的内皮细胞增殖,同时也剂量依赖性地抑制VEGF诱导的内皮细胞的迁移和小管生成。结论：EGCG多靶点作用于VEGF信号通路,抑制胃癌生长和血管生成。     

Suppression of advanced human prostate tumor growth in athymic mice by silibinin feeding is associated with reduced cell proliferation, increased apoptosis, and inhibition of angiogenesis.

Recently, we observed that dietary feeding of silibinin strongly prevents and inhibits the growth of advanced human prostate tumor xenografts in athymic nude mice without any apparent signs of toxicity together with increased secretion of insulin-like growth factor-binding protein 3 from the tumor in to mouse plasma (R. P. Singh et al., Cancer Res., 62:3063-3069, 2002). In the present study, we investigated the effect of silibinin feeding [0.05% and 0.1% (w/w) in diet for 60 days] on the prognostic biomarkers (namely, proliferation, apoptosis, and angiogenesis) in the prostate tumor xenografts of the above-reported study. Immunohistochemical analysis of the tumors for proliferating cell nuclear antigen and Ki-67 showed that silibinin decreases proliferation index by 28-60% and 30-60% (P<0.001) as compared with their controls, respectively. In situ detection of apoptosis by terminal deoxynucleotidyl transferase dUTP-mediated nick end labeling staining of tumors showed a 7.4-8.1-fold (P<0.001) increase in apoptotic cells in silibinin-fed groups over that of control group. Silibinin also increased activated caspase 3-positive cells by 2.3-3.6-fold (P<0.001). CD31 staining for tumor vasculature showed a significant decrease (21-38%; P<0.001) in tumor microvessel density in silibinin-fed groups of tumors as compared with control group of tumors. Tumor sections were also analyzed for vascular endothelial growth factor and insulin-like growth factor-binding protein 3 protein expression, and a slightly decreased and a moderately increased cytoplasmic immunostaining in silibinin-fed groups were observed as compared with the control group, respectively. Together, these results suggest that inhibition of advanced human prostate tumor xenograft growth in athymic nude mice by silibinin is associated with its in vivo antiproliferative, proapoptotic, and antiangiogenic efficacy in prostate tumor.     

CH50多肽真核表达载体pCH510的构建、表达及体内趋化和抑瘤作用

目的：探讨血管内皮生长因子的表达与肿瘤血管生成的关系。方法：将VEGF165正、反义RNA表达载体导入人胃癌细胞,观察接种VEGF高表达和低表达胃癌细胞裸鼠移植瘤的生长情况,并对移植瘤进行组织学检查,检测其血管密度、组织增生及环死程度等变化。结果：VEGF正义转染细胞所致移植瘤的生长速度明显快于反义转染细胞所致的移植瘤;组织学检查发现,正义转染细胞移植瘤的血管密度显著高于的转染细胞所致的肿瘤。结论：血管皮生长因子通过启动血管生成而促进肿瘤的生长,阻断血管内皮生长因子的产生可以抑制肿瘤的生长。     

血管内皮生长因子的表达和血管生成与人胃癌移植瘤生长的关系

探讨血管内皮生长因子的表达与肿瘤血管生成的关系。方法 :将VEGF165正、反义RNA表达载体导入人胃癌细胞 ,观察接种VEGF高表达和低表达胃癌细胞裸鼠移植瘤的生长情况 ,并对移植瘤进行组织学检查 ,检测其血管密度、组织增生及坏死程度等变化。结果 :VEGF正义转染细胞所致移植瘤的生长速度明显快于反义转染细胞所致的移植瘤 ;组织学检查发现 ,正义转染细胞移植瘤的血管密度显著高于反义转染细胞所致的肿瘤。结论 :血管内皮生长因子通过启动血管生成而促进肿瘤的生长 ,阻断血管内皮生长因子的产生可以抑制肿瘤的生长。     

Ablation of peripheral dopaminergic nerves stimulates malignant tumor growth by inducing vascular permeability factor/vascular endothelial growth factor-mediated angiogenesis

Many important physiological and pathological processes are modulated by angiogenesis. It has been shown that initiation of this angiogenic process is an essential early step in the progression of malignant tumors. We report here that ablation of peripheral dopaminergic nerves markedly increased angiogenesis, microvessel density, microvascular permeability, and growth of malignant tumors in mice. Endogenous peripheral dopamine acted through D2 receptors as significantly more angiogenesis and tumor growth was observed in D2 dopamine receptor knockout mice in comparison with controls. The vascular endothelial growth factor receptor 2 phosphorylation, which is critical for promoting angiogenesis, was also significantly more in tumor endothelial cells collected from the dopamine-depleted and D2 dopamine receptor knockout animals. These results reveal that peripheral endogenous neurotransmitter dopamine might be an important physiological regulator of vascular endothelial growth factor-mediated tumor angiogenesis and growth and suggest a novel link between endogenous dopamine, angiogenesis, and tumor growth.     

Ad．VEGF．siRNA抑制荷人骨肉瘤裸鼠血管生成的形态学研究

背景与目的：血管内皮生长因子是骨肉瘤血管形成重要的促进因子,本研究通过抗血管生成方法,观察其抑制荷人骨肉瘤裸鼠血管生成的形态学表现。方法：取4～8周龄的Balb／c裸鼠作为实验动物,人骨肉瘤细胞株MG63皮下接种法构建骨肉瘤的动物模型。建模成功后将荷人骨肉瘤的裸鼠随机分为3组,每组15只。A组使用自行构建的Ad—VEGF-siRNA干扰新生血管形成;B、C组分别使用等剂量的Ad-EGFP或PBS作为对照。实验维持19d,药物使用后隔日测量肿瘤体积和体重．绘制肿瘤生长曲线：采用常规HE染色、VEGF和CD31相关抗原免疫组化染色观察各组肿瘤标本：各组随机抽取一个标本在透射电镜下观察仿血管发生的超微结构。结果：实验结束时,A组裸鼠瘤体体积为（0．31±0．18）cm^3,重量为（0．75±0．21）g,微血管密度（microvessed density,MVD）为5．79±0．34,VEGF表达为235228．09±123244．41,B、C照组裸鼠瘤体积分别为（1．21±1．29）cm^3、（1．43±0．95）cm^3;瘤重分别为（1．19±0．27）g、（1．19±0．35）g;MVD分别为11．00±0．68、10．42±0．10：VEGF表达分别为9641992．40±90479．62、981298．00±213590．50。A组肿瘤体积、重量、MVD和VEGF表达均显著低于B、C组。MVD和VEGF呈正相关关系,相关系数为0．9989。Ad-VEGF—siRNA组仿血管发生数量1．4000±0．5477,明显小于Ad—EGFP和PBS对照组。透射电镜可见肿瘤细胞形成的仿血管。结论：通过宏观和微观的形态学观察,证实Ad—VEGF-siRNA介导的以VEGF为靶向的抗血管生成能够抑制荷人骨肉瘤裸鼠的血管生成。     

Epidermal growth factor receptor blockade with C225 plus gemcitabine results in regression of human pancreatic carcinoma growing orthotopically in nude mice by antiangiogenic mechanisms.

Both epidermal growth factor receptor (EGF-R) signaling mechanisms and angiogenesis have been evaluated as independent targets for therapy of human pancreatic carcinoma, but a link between the two processes has been identified only recently. This study evaluated whether EGF-R blockade therapy with anti-EGF-R antibody C225 inhibits pancreatic carcinoma growth and metastasis in an orthotopic nude mouse model via tumor-mediated angiogenesis and whether gemcitabine potentiates this effect. In vitro treatment of human pancreatic carcinoma L3.6pl cells with C225 inhibited EGF-R autophosphorylation, producing a maximum of 20% cytostasis. Treatment with C225 plus gemcitabine resulted in additive cytotoxic effects that increased with increasing gemcitabine concentrations. Dose-dependent decreases in expression of the angiogenic factors vascular endothelial growth factor and interleukin 8 (but not basic fibroblast growth factor) were observed in the C225-treated cells (mRNA and protein levels). In L3.6pl tumors established in the pancreas of nude mice, systemic therapy with C225 alone and C225 in combination with gemcitabine resulted in growth inhibition, tumor regression, and abrogation of metastasis; median tumor volume was reduced from 538 to 0.3 and to 0 mm3, respectively. Gemcitabine treatment alone reduced median tumor volume from 538 to 152 mm3. Liver metastases were present in 50% of the controls, 30% of the gemcitabine-treated animals, and 20% of C225-treated animals. No macroscopically visible liver metastases were observed in the combination treatment group. As early as 11 days after C225 treatment, the median percentage of proliferating cell nuclear antigen-positive cells was substantially reduced compared with gemcitabine treatment alone (26% versus 73%, respectively) versus controls (92%), correlating with in vivo blockade of EGF-R activation. Similarly after 11 days treatment, production of vascular endothelial growth factor and interleukin 8 was significantly lower in C225 and C225 plus gemcitabine-treated tumors versus gemcitabine-treated and control tumors. Significant differences in microvessel density were observed 18 days after C225 or combination treatments (but not gemcitabine alone) in direct correlation with the difference in percentage of apoptotic endothelial cells, as visualized by double immunofluorescence microscopy. These experiments indicate that therapeutic strategies targeting EGF-R have a significant antitumor effect on human L3.6pl pancreatic carcinoma growing in nude mice which is mediated in part by inhibition of tumor-induced angiogenesis, leading to tumor cell apoptosis and regression. Furthermore, this effect is potentiated in combination with gemcitabine.