A novel gene delivery system targeting cells expressing VEGF receptors

Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors.GV1,GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine and the resulting conjugates could interact with DNA in a noncovalent bond to form a complex.Using pSV2-β-galactosidase as a reporter gene,it has been demonstrated that exogenous gene was transferred into bovine aortic arch-derived endothelial cells (ABAE) and human malignant melanoma cell lines (A375) in vitro.In vivo experiments,exogenous gene was transferred into tumor vascular endothelial cells and tumor cells of subcutaneously transplanted human colon cancer LOVO,human malignant melanoma A375 and human hepatoma graft in nude mice.This system could also target gene to intrahepatically transplanted human hepatoma injected via portal vein in nude mice.These results are correlated with the relevant receptors(flt-1,flk-1/KDR) expression on the targeted cells and tissues.     

裸鼠肿瘤动物模型VEGF受体表达及其意义

目的　通过免疫组织化学染色了解flt 1与flk 1 KDR(VEGF的两个高亲和受体 )在人肿瘤细胞皮下接种肿瘤动物模型的血管内皮细胞与肿瘤细胞中的表达。方法　取荷瘤裸鼠皮下接种瘤块 ,漂洗、固定、石蜡连续切片 ,进行两种受体相应免疫组化检测。结果　在 13种荷瘤裸鼠血管内皮细胞及肿瘤细胞中flt 1的阳性率大部分为强阳性或中阳性 ,而只有在荷人胃腺癌MKN 4 5裸鼠的肿瘤细胞中flt 1的阳性率为弱阳性 ,在荷人卵巢癌SKOv3裸鼠的肿瘤细胞中flt 1的表达为阴性。相比较而言 ,在 13种荷瘤裸鼠血管内皮细胞及肿瘤细胞中KDR的阳性率大部分为中阳性或弱阳性 ,并且在荷人肝癌SMMC 772 1裸鼠 ,荷人胃腺癌SPC A1裸鼠 ,荷人高转移肝癌移植瘤裸鼠 ,荷人卵巢癌SKOv3裸鼠的肿瘤细胞中 ,荷人宫颈癌移植瘤裸鼠和荷人胃腺癌MKN 4 5裸鼠的肿瘤细胞中 ,KDR表达为阴性。结论　VEGF受体共同表达于肿瘤血管内皮细胞与肿瘤细胞 ,提示了VEGF与VEGF受体结合作用在肿瘤演化中的重要性 ,为靶向于VEGF受体的基因治疗策略选择裸鼠动物模型提供了参考依据     

胡桃醌不同给药途径对人肝癌细胞BEL-7402裸鼠皮下移植瘤生长的影响

目的采用裸鼠皮下移植瘤模型,通过不同给药途径对胡桃醌抗肿瘤活性和毒性进行评价。方法建立人肝癌BEL-7402细胞裸鼠皮下移植瘤模型,通过腹腔注射和局部注射两个给药途径观察胡桃醌抑制肿瘤生长的效果。结果①以600、300和150μg/kg胡桃醌腹腔注射于人肝癌BEL-7402细胞裸鼠皮下移植瘤模型,发现该剂量胡桃醌对肿瘤生长没有明显的影响;NK细胞活性检测发现,600、300μg/kg胡桃醌对裸鼠免疫功能有影响(P均<0.01),150μg/kg胡桃醌则没有影响(P>0.05);与阳性对照组(5-Fu)相比,600μg/kg胡桃醌组NK细胞活性差异无显著性(P>0.05),300和150μg/kg胡桃醌组NK细胞活性差异有显著性(P<0.05,P<0.01),结果提示胡桃醌对小鼠免疫系统有一定的损伤作用。②以4.5、3和1.5 mg/kg胡桃醌腹腔注射于人肝癌BEL-7402细胞裸鼠皮下移植瘤模型,抑瘤率分别为为78.24%、66.57%、48.94%;4.5、3 mg/kg胡桃醌的抑瘤作用可与阳性对照组比拟(P均>0.05)。但4.5 mg/kg胡桃醌组裸鼠出现明显的皮下脂肪减少、消瘦,并有死亡现象。③以pH 7.4和pH 4.0的600、300和150μg/kg胡桃醌人肝癌BEL-7402细胞裸鼠皮下移植瘤模型局部给药,结果发现不同pH(pH 7.4或4.0)600、300μg/kg的胡桃醌局部注射抑瘤作用与阳性对照组(5-Fu)组差异无显著性(P>0.05),而不同pH的150μg/kg胡桃醌抑瘤作用不明显。同一浓度不同pH药物的抑瘤作用差异无显著性(P均>0.05),但pH 4.0的胡桃醌组肿瘤细胞肝转移较少。结论胡桃醌不同给药途径均可抑制人肝癌BEL-7402细胞裸鼠皮下移植瘤的生长,但有一定的毒副作用,药物安全范围较小。     

A monoclonal antibody to the carbohydrate chain on human hepatocellular carcinoma-associated antigen which suppressed tumor growth in nude mice

Summary There have been few reports stating that monoclonal antibody alone inhibits human solid tumor growth in vivo. The present study demonstrated that monoclonal antibody S1 (IgG2a), which recognized the antigenic determinant of the carbohydrate moiety, showed antibody-dependent cell (or macrophage)-mediated cytotoxicity (ADCC or ADMC) in conjunction with murine splenocytes of both BALB/c and athymic mice. In vivo experiments demonstrated that the antibody S1 clearly prolonged the survival of athymic mice which had been inoculated with a human liver carcinoma cell line. In addition, the antibody S1 significantly suppressed the human hepatoma line transplanted s.c. into nude mice. ¹²⁵I-Labeled monoclonal antibody S1 revealed that the antibody accumulated significantly in the tumor mass. Many mononuclear cells were observed surrounding tumor cells when the antibody was given. This model system might be useful for analyzing the ADCC (or ADMC) mechanism in vivo.     

Suicide gene therapy of human hepatoma and its peritonitis carcinomatosis by a vector of replicative-deficient herpes simplex virus

Herpes simplex virus type 1 (HSV-1) deleted for the immediate-early gene was applied for treatment of hepatoma cells of SKHep 1 and Huh-7. Hepatoma cells were cultured in medium containing HSV1 expressing GFP gene (QOZ/HG) to determine its transfection rate, and both cell lines infected by MOI 1 of QOZ/HG were found to have high expression of GFP without cytotoxicity. Subcutaneous growth of SKHep 1 cell tumor in nude mice was significantly reduced by injection of replicative-deficient herpes virus (TOZ.1) containing Tk-gene with administration of GCV, in comparison with that of noninjected tumor. SCID mice of peritonitis carcinomatosis due to Huh-7 hepatoma cells infected with TOZ.1 could survive longer under administration of GCV than those without TOZ.1. Therefore replicative-deficient HSV1 is a useful vector for treatment of human hepatoma cells, and TOZ.1 with GCV may be applied to suicide gene therapy for hepatoma and peritonitis carcinomatosis of hepatoma cells.     

Circumvention of multidrug resistance and reduction of cardiotoxicity of doxorubicin in vivo by coupling it with low density lipoprotein

Doxorubicin (Dox) was coupled into human low density lipoprotein (LDL) to form a complex LDL-Dox. In in vitro studies, the accumulation of LDL-Dox in human resistant hepatoma (R-HepG2) cells was found to be higher than that of free Dox in the cells, resulting in an increase of the cytotoxic effect on the cells. Moreover, in in vivo studies, under the same dosage of drugs (1 mg/kg), the anti-proliferative effect on the tumor cells of LDL-Dox in nude mice bearing R-HepG2 cells was higher than that of free Dox as evidenced by the larger reduction in tumor volumes and tumor weights in LDL-Dox treated group. Histological studies showed that LDL-Dox treatment did not cause any heart damage when compared with the control group. In contrast, Dox treatment caused disruption and vacuolization of myocardial filament. Plasma lactate dehydrogenase activity and plasma creatine kinase activity in nude mice bearing R-HepG2 cells were found to be elevated in the Dox-treated group but remained unchanged in LDL-Dox-treated group. The present studies indicate that when Dox is coupled with LDL, the multidrug resistance can be circumvented and the cardiotoxicity can be reduced.     

人结肠癌SW480细胞裸鼠皮下移植瘤DcR3基因的RNA干扰及其作用

目的:观察DcR3基因小干扰RNA(siRNA)对人结肠癌SW480细胞裸鼠皮下移植瘤DcR3基因表达的影响。方法:建立结肠癌SW480细胞裸鼠皮下移植瘤模型,瘤体注射脂质体与DcR3siRNA混合物,转染DcR3siRNA,免疫组织化学及RT-PCR检测观察DcR3基因的表达。结果:建立了结肠癌SW480细胞裸鼠皮下移植瘤模型;治疗后,治疗组移植瘤明显减小,空白对照组、阴性对照组肿瘤体积显著大于治疗组(P<0.01);各组肿瘤组织中DcR3基因均有不同程度的表达,治疗组表达程度明显低于阴性对照组及空白对照组(RT-PCRP<0.05,免疫组化P<0.01)。结论:人结肠癌SW480细胞在裸鼠皮下有良好的成瘤性;脂质体与DcR3siRNA混合物可特异性抑制结肠癌裸鼠皮下移植瘤内DcR3基因的表达。     

人卵巢癌裸鼠移植实体瘤模型的建立

目的建立人卵巢癌裸鼠移植实体瘤模型。方法将1例人卵巢癌组织移植裸鼠,建立人卵巢癌裸鼠原代移植实体瘤模型的基础上,再将实体瘤皮下移植、实体瘤原位移植、实体瘤细胞移植裸鼠。观察裸鼠实体瘤生长和转移情况,称量其体重、子宫卵巢重、瘤重及瘤的大小,并作病理、电镜、染色体检查。结果成功地建立人卵巢癌裸鼠移植实体瘤模型,并已传至第18代,传代移植成功率100％,组织学和超微结构形态均证明该实体瘤保留了原人卵巢癌特征,有人卵巢癌染色体特征,并出现肝、脾转移。结论本研究建立人卵巢癌裸鼠移植实体瘤模型与人相似,通过18代传代和实验观察方法稳定可靠。为人卵巢癌的研究提供了理想的动物模型。     

The effect of tripeptide tyroserleutide (YSL) on animal models of hepatocarcinoma

This study aimed to observe the effects of tyroserleutide (tyrosyl-seryl-leucine, YSL) on the survival time of mice transplanted with the ascitic fluid-type hepatocarcinoma H22, as well as the inhibitory effect of tyroserleutide on the human hepatocarcinoma Bel-7402 that was transplanted into nude mice. At doses of 80, 20 and 5 microg/kg/d, tyroserleutide significantly prolonged the survival of mice transplanted with H22 tumor cells, producing survival rates of 89%, 39% and 49%, respectively, which were statistically significantly different from the saline group (P < 0.05). YSL, at doses of 80, 160 and 320 microg/kg/d significantly inhibited the growth of the human hepatocarcinoma Bel-7402 tumor in nude mice, producing inhibition of 40%, 64% and 59%, respectively; this inhibition was significantly greater than that by saline (P < 0.05). HE staining and electron microscopy of the pathological changes of the tumor in nude mice showed that YSL changed the structure Bel-7402 tumor cells that were transplanted into nude mice, and also induced tumor cell apoptosis and necrosis, which could be a mechanism by which YSL inhibits the tumor growth in animal models.     

The elimination of mouse hepatitis virus by temporary transplantation of human tumors from infected athymic nude mice into athymic nude rats (rnuN/rnuN).

A nude mouse colony held in an isolation unit was found to harbor MHV despite the fact that all hygienic precautions were taken. The virus spread rapidly causing a high mortality rate predominantly in experimental animals. Moreover, we observed a high percentage of tumor regression in our tumor transplanted mice. Attempts to eliminate the MHV by repeated tumor transplantation into virus-free nude mice were unsuccessful. Since MHV has a limited host range, we transplanted, in parallel, four different lines of embryonic renal tumors (three triphasic nephroblastomas and one malignant rhabdoid tumor of the kidney) from athymic mice into athymic rats and fragments of the same tumors into "fresh" nude mice. All manipulations were performed in isolators. Detection of MHV was done twice by serological examination of six-week-old sentinels. The results showed transmission of MHV infection in the control mice under gnotobiotic conditions as previously found in the normal animal room. On the other hand, there was no evidence of infection, neither in the transplanted nude rats nor after retransplantation of tumors into nude mice. We hypothesize that the virus is harbored in the stromal cells of the murine host but not of the rat host nor in the human tumor cells. Histological comparison showed no alteration of specific tumor morphology in the different hosts.     

Characterization of tumor-associated fucogangliosides from PC 12 pheochromocytoma cells

PC 12h pheochromocytoma cells were subcutaneously transplanted into rat. We found the transplanted tumors accumulated some fucogangliosides associated with PC 12 cells. These gangliosides were isolated and purified by DEAE-Sephadex A-25 and Iatrobeads column chromatographies. Their structures were determined by fast atom bombardment mass spectrometry, proton nuclear magnetic resonance spectrometry, permethylation study, and sequential degradation using various exoglycosidases and mild acid hydrolysis. Two tumor-associated fucogangliosides were found to possess the blood group B determinant as follows: G6: IV2Fuc alpha, IV3Gal alpha, II3NeuAc, GgOse4Cer; G11: IV2Fuc alpha, IV3Gal alpha, II3 (NeuAc)2, GgOse4Cer. A ganglioside with the similar structure as ganglioside G6 was isolated from rat hepatoma cells (Holmes, E.H., and Hakomori, S-I. (1982) J. Biol. Chem. 257, 7698-7703). However, ganglioside G11 has not previously been reported in the literature. These fucogangliosides reacted with the monoclonal antibody prepared by immunizing mice with PC 12h cells. Other fucogangliosides were also found to accumulate in the transplanted tumor tissues. They were identified as fucosyl-GM1 and fucosyl-GDlb. These fucogangliosides did not react with the monoclonal antibody against PC 12h cells.     

苦杏仁苷介导人肝癌细胞HuH-7凋亡的实验研究

摘要 目的：通过体内体外实验探讨苦杏仁苷在肝癌中的抗肿瘤作用。方法：MTT 法检测不同浓度的苦杏仁苷对肝癌 HuH-7细胞存活率的影响;DAPI染色法观察苦杏仁苷介导HuH-7细胞的凋亡形态学变化;流式细胞术检测苦杏仁苷干预后HuH-7细胞凋亡率变化;Western Blot法检测细胞凋亡相关蛋白Bax、Bcl-2的表达,计算Bax/Bcl-2的比值。建立裸鼠HuH-7细胞移植瘤模型,观察苦杏仁苷对荷瘤裸鼠移植瘤体积的影响。结果：体外实验结果证实苦杏仁苷能够诱导人肝癌HuH-7细胞凋亡的发生（P<0.05）。随着苦杏仁苷浓度的增加,HuH-7细胞的存活率降低,凋亡率升高,干预后Bax/Bcl-2比值明显升高（P<0.05）。体内实验结果表明,裸鼠HuH-7细胞移植瘤的体积增长速度减慢（P<0.05）。结论：苦杏仁苷能够诱导人肝癌HuH-7细胞和裸鼠HuH-7细胞移植瘤细胞发生凋亡,减缓肿瘤生长,从而发挥抗肿瘤作用。     

Changes in ganglioside contents, plasma sialic acid and cAMP levels in experimental hepatoma in mice

The present study was designed to assess whether changes in glycolipids and cyclic AMP contents might serve as markers for the diagnosis of malignancy in the liver. The experimental model was a transplantable murine hepatoma. Experimental mice were divided into three groups: (1) a therapeutic group, which had been transplanted with hepatoma and treated with the antimetabolism drug 5-flurouracil (0.2 mg/day i.p.), (2) a control group, which had been transplanted with hepatoma and treated with 0.2 ml 0.9% NaCl/day and (3) a normal group of mice. The ganglioside and cAMP contents in the hepatoma tissue, plasma cAMP, total- and lipid-bound sialic acid levels and red blood cell membrane sialic acid levels were determined. Results showed that the ganglioside content, total and lipid-bound sialic acid levels in the control group were significantly higher than those in the livers of normal mice (p < 0.01) while these respective values in the therapeutic group were significantly lower than those in the control group (p < 0.01). The cAMP levels of tumor tissues and plasma in the control group were lower than those in normal mice. No significant difference in red blood cell membrane sialic acid content was observed between the therapeutic and control groups though levels for both were higher than those in normal mice. These results indicate that ganglioside content and sialic acid levels in hepatoma tissues were significantly elevated, and cAMP levels in hepatoma tissues were significantly decreased during proliferation and abnormal differentiation.     

Effect of chemotherapy on human tumor heterografts and lymphocytes in athymic mice

Sensitivity of human serially transplanted tumours (melanoma, hepatoma, lung, stomach and bladder cancer) to monochemotherapy was studied in nude mice. The following groups of nude mice were examined: intact and those with human xenografts (control and mice treated with alkylating agents). Changes in peripheral blood morphology have been revealed and functional activity of the energetic enzymes (SDH and alpha-GPDH) has been cytochemically discovered.     

重组腺相关病毒介导的RNAi靶向治疗作用研究

目的:采用前期成功构建的靶向沉寂CDK2基因的重组腺相关病毒r AAV-sh RNA-CDK2转染人肝癌Hep G2细胞,研究其对人肝癌细胞增殖的抑制作用。方法:取人肝癌Hep G2细胞于裸鼠前肢腋下接种,构建裸鼠皮下移植瘤模型,将成瘤裸鼠随机分为三组:肿瘤组、NC对照组、r AAV-sh RNA-CDK2给药组。各试验组均通过尾静脉注射给药,每隔五天用游标卡尺测量肿瘤的长径(a)、短径(b),计算肿瘤体积。根据每组裸鼠移植瘤体积的平均值,绘制移植瘤生长曲线。于给药24 h后处死,称取瘤重,计算抑瘤率,应用实时荧光定量PCR和Western blot方法检测各组肝癌组织中CDK2基因m RNA和蛋白的表达量,观察r AAV-sh RNA-CDK2对肝癌组织CDK2表达的影响;结果:r AAV-sh RNA-CDK2能够显著抑制肝癌Hep G2细胞的增殖,其抑瘤率为72.18%;并能够下调肝癌组织中CDK2基因m RNA与蛋白表达量;结论:r AAV-sh RNA-CDK2实现了体内靶向治疗肝癌的目的,并确定静脉定量给药方式。     

Human immunodeficiency virus (HIV)-infected tumor xenografts as an in vivo model for antiviral therapy: role of alpha/beta interferon in restriction of tumor growth in nude mice injected with HIV-infected U937 tumor cells.

The host factors involved in the restriction of tumor growth were studied in nude mice transplanted with a cloned line of chronically human immunodeficiency virus (HIV)-infected U937 cells. HIV-infected and uninfected U937 cells exhibited the same growth patterns in culture. However, HIV-infected cells were not tumorigenic when injected subcutaneously in nude mice, whereas large solid tumors were observed in mice injected with uninfected U937 cells. Injection of nude mice with antibody to alpha/beta interferon (IFN-alpha/beta) enabled HIV-infected U937 cells to grow progressively in approximately 90 to 100% of mice. HIV-infected U937 cells formed solid tumors in the majority (60 to 90%) of either immunosuppressed (splenectomized, irradiated, and anti-asialo-GM1-treated) or genetically immunodeficient (bg/nu/xid) nude mice. In mice treated with antibodies to IFN-alpha/beta with established HIV-positive tumors, a direct correlation was found between p24 antigenemia and tumor size. Treatment of established HIV-positive U937 cell tumors with human IFN-alpha or mouse IFN-alpha/beta resulted in a clear-cut inhibition of both tumor growth and p24 HIV antigenemia. In contrast, treatment with tumor necrosis factor alpha markedly inhibited tumor growth but did not significantly decrease serum p24 levels. 3'-Azido-3'-deoxythymidine treatment did not affect either tumor growth or the levels of serum p24 antigen. These data indicate that endogenous IFN-alpha/beta is a crucial factor in the restriction of both tumor growth and p24 antigenemia in mice injected with HIV-infected tumor cells. Moreover, the results suggest that the development of HIV-1 p24 antigenemia in athymic immunosuppressed mice may represent an interesting in vivo model for anti-HIV therapy.     

癌基因及癌发育基因在裸小鼠人肝癌移植瘤中表达

本文采用Northern blot,斑点杂交,western Immunoblot,凝集素亲和电泳及聚丙烯酰胺梯度电泳方法分别检测裸小鼠肝癌移植瘤中C-ras基因簇(N-ras,H-ras及K-ras),甲种胎儿蛋白以及γ谷氨酰转肽酶(GGT)基因及其产物的表达。结果提示C-ras基因簇均有不同程度的表达,其中N-ras基因表达水平要比H-ras高8倍,比K-ras高20倍左右,同样AFP及GGT基因均有较高水平的表达。经ras-p21单克隆抗体检测,发现肝癌组织抽提液中p21呈现阳性反应;AFP亚型分析提示AFP分子变异体属肝癌特异性分子亚型;GGT同Ⅰ酶酶谱分析表明组织中仅合成肝癌特异性GGT同Ⅰ酶酶谱(Ⅰ’,Ⅱ’)。上述结果充分表明癌基因及癌发育基因的高表达可能与癌细胞去分化性,分裂旺盛程度及细胞恶性度相关。最后文内还对裸小鼠人肝癌移植瘤中二类基因的相关性作一定的讨论。     

Inhibitory effect of parvovirus H—1 on the formation of colonies of human hepatoma cell line in vitro and its tumors in nude mice

The inhibitory effect of parvovirus H-1 on the colonyforming ability.in vitro of QGY-7703,a cultured human hepatoma cell line,and on the formation and growth of its tumors in nude mice was studied.With higher multiplicity of infection(MOI) of H-1 given,survival of the QGY-7703 cells was found to be decreased.H-1 DNA amplification level at 30h postinfection(p.i.) was detected to be 7.4 times higher than that at 2h by dispersed cells assay,while the cells were delayed to enter into S phase.Plaques were formed in the indicator cells(new-born human kidney cell line,NBK) by progeny H-1 virus particles released from the infected QGY-7703 cells by infectious cell center assay.The formation of tumors in nude mice by QGY-7703 cells which were injected s c at 2h postinfection was observed to by prevented in 2 proups with given MOI 25 and 50.The tumor growth of MOI 10 group occurred at a lower exponential rate than that of control,after a 20d latent period.It was evident that parvovirus H-1 exhibited a direct inhibitory effect on the formation and growth of human hepatoma cells in vivo as well as in vitro.     

Generation of cells with phenotypes of both intercalated duct-type and myoepithelial cells in human parotid gland adenocarcinoma clonal cells grown in athymic nude mice

A neoplastic epithelial cell line was established from nude mice tumors grown after transplantation of surgical specimens from a human parotid gland adenocarcinoma. This cell line, which had ultrastructure similarities to salivary intercalated duct cells, was found by immunohistochemical techniques to contain amylase, but myosin was not detected. Ultrastructurally, cells of an intermediate type between intercalated ductal and myoepithelial cells were found in the transplanted tumors. Moreover, the expression of myosin in addition to the presence of amylase was detected in the tumors. These findings indicate that some transplanted tumor cells appear to be differentiating towards myoepithelial cells.     

A transgenic red fluorescent protein‐expressing nude mouse for color‐coded imaging of the tumor microenvironment

The tumor microenvironment (TME) is critical for tumor growth and progression. We have previously developed color‐coded imaging of the TME using a green fluorescent protein (GFP) transgenic nude mouse as a host. However, most donor sources of cell types appropriate for study in the TME are from mice expressing GFP. Therefore, a nude mouse expressing red fluorescent protein (RFP) would be an appropriate host for transplantation of GFP‐expressing stromal cells as well as double‐labeled cancer cells expressing GFP in the nucleus and RFP in the cytoplasm, thereby creating a three‐color imaging model of the TME. The RFP nude mouse was obtained by crossing non‐transgenic nude mice with the transgenic C57/B6 mouse in which the β‐actin promoter drives RFP (DsRed2) expression in essentially all tissues. In crosses between nu/nu RFP male mice and nu/+ RFP female mice, the embryos fluoresced red. Approximately 50% of the offspring of these mice were RFP nude mice. In the RFP nude mouse, the organs all brightly expressed RFP, including the heart, lungs, spleen, pancreas, esophagus, stomach, duodenum, the male and female reproductive systems; brain and spinal cord; and the circulatory system, including the heart, and major arteries and veins. The skinned skeleton highly expressed RFP. The bone marrow and spleen cells were also RFP positive. GFP‐expressing human cancer cell lines, including HCT‐116‐GFP colon cancer and MDA‐MB‐435‐GFP breast cancer were orthotopically transplanted to the transgenic RFP nude mice. These human tumors grew extensively in the transgenic RFP nude mouse. Dual‐color fluorescence imaging enabled visualization of human tumor–host interaction. The RFP nude mouse model should greatly expand our knowledge of the TME. J. Cell. Biochem. 106: 279–284, 2009. © 2008 Wiley‐Liss, Inc.