Ocular tissue interactions during the development of human fetal neuroretina grafted into nude mice

To determine the roles of different ocular tissues in the development of the human fetal neuroretina, a study ethically and technically impossible in human subjects, human embryonic and fetal retinas were heterotopically implanted into nude mice. Ninety-five eyeballs were obtained from legally aborted 6- to 7-week-old embryos or 8- to 10-week-old fetuses. Ten isolated neuroretinas with vitreous but without pigment epithelium, 20 half-eyeballs and 70 intact eyeballs, of which 12 had a thick layer of periocular tissue, were microsurgically grafted. Five intact eyeballs were used for reference. Over a period of 1-245 days, all of the grafts were removed for light and electron microscopy observations. All of the isolated neuroretinas had disappeared by the second day after transplantation. Grafts of the posterior section of the eyeball contained only some clusters of pigment epithelium, occasionally covered with undifferentiated neuroretinal cells. Grafts of the retrolental section of the eyeball contained small areas of dysplasic neuroretina with folds and rosettes. Grafts of the 70 intact eyeballs were successful, but only 26 showed normal histological organization of the choriocapillaris, the retinal pigment epithelium and the neuroretina in the posterior part of the posterior chamber. Photoreceptor differentiation was evident in these retinas after approximately 80 days of transplantation and was complete after 166 days. Their anterior part was always dysplasic, with occasional ciliary differentiation. Twenty-three grafted eyeballs had a dysplasic neuroretina with folds, rosettes and necrotized areas. Twenty-one were atrophic, 12 of which were the eyeballs grafted with periocular tissue. These results demonstrate the role of the fetal mesenchyme and pigment epithelium in the rapid revascularization, and subsequent survival and tissue organization, of the neuroretina. The stratified development of the neuroretina required a thin mesenchymal environment for revascularization of the graft by human vasculogenesis or neoangiogenesis and a normal retinal pigment epithelium for normal neuroretinal differentiation. When these conditions were not satisfied, the neuroretina disappeared or was dysplasic, partly necrotized or atrophic. This model might prove useful for a number of therapeutic or clinical studies.     

Differences in Plasmodium berghei development in nude and normal mice

Mcguire R. W. 1984. Differences in Plasmodium berghei development in nude and normal mice. International Journal for Parasitology14: 57–61. Parasitemia is a cumulative index of hostparasite responses which constitutes a dynamic cycle of affector-effector mechanisms. Therefore, it is necessary to view these responses as host or parasite in nature and this investigation focused on parasite responses. This study supports previous findings, i.e., congenitally athymic (nu/nu) mice maintain higher parasitemias than control (nu/+) animals. Analysis of these differences demonstrate that, in the erythrocytic phase, the frequency of schizonts, the frequency of multiple-infected red blood cells and the number of nuclei per schizont are dependent on the immunological state of the host. Collectively, parasite developmental characteristics suggest that Plasmodium berghei has a greater reproductive capability and possibly a higher degree of sequestration while developing in nude mice.     

基于临床肿瘤标本的胃癌转移模型建立

目的建立基于临床肿瘤标本的胃癌转移模型,为胃癌的转移研究提供个体化动物模型。方法将胃癌新鲜的手术标本移植到裸鼠皮下,建立胃癌患者异种移植(patient-derived xenograft,PDX)模型。进一步通过手术将皮下瘤组织原位移植到裸鼠胃部肌层,连续观察裸鼠的体征状态,通过近红外荧光活体成像技术检测肿瘤转移的发生。解剖荷瘤小鼠,将肺部转移灶进一步移植裸鼠皮下获得实体瘤。HE染色观察原发瘤与转移瘤的结构特征,(short tandem repeat) STR分析原发瘤和转移瘤的遗传特性。PCR-Array分析转移瘤和原发瘤中转移相关基因的表达。结果成功建立胃癌PDX模型,移植瘤组织结构与患者保持基本一致;通过胃部原位移植发现编号C19751的小鼠发生肺和肝的转移。其中肺转移灶皮下移植后获得了实体瘤,STR分析显示原发瘤保持了与肺转移瘤一致的遗传特征。PCR-Array结果显示,与原发瘤相比,转移瘤中CXCL12,IGF1和MMP2基因表达均显著上调。结论利用临床肿瘤标本成功建立胃癌转移模型,为胃癌转移研究提供了良好的个体化模型。     

In vivo effects of human recombinant tumor necrosis factor alone and in combination with other biological response modifiers on human digestive organ cancer xenografts transplanted in nude mice

The present study was designed to evaluate the effect of rTNF alone or in combination with other BRMs on human digestive organ cancers. Six kinds of human digestive organ cancer xenografts (esophageal, stomach, colonic, pancreatic, bile duct, and liver cancers: EC-YO, GC-YN, CC-KK, PC-HN, BDC-SN and Li-7, respectively) were transplanted in nude mice, and rTNF was administered at 10³, 5 × 10³, or 10⁴U/head directly into the tumor 3 times a week for 2 weeks. EC-YO was the most sensitive to rTNF, and intratumoral administration of rTNF at 10³ U/head caused tumor regression. PC-HN, CC-KK and GC-YN were relatively sensitive to rTNF, and their growth was significantly inhibited by rTNF at 5 × 10³ U/head, however, the tumors regrew after treatment. Li-7 and BDC-SN were resistant to rTNF. The effects of rTNF in combination with recombinant interferon- (rIFN-), recombinant interleukin-2 (rIL-2), or streptococcal preparation OK-432 were assessed in mice transplanted with GC-YN. All combinations of rTNF at 5 × 10³ U/head and other BRMs were more effective than rTNF alone, and GC-YN tumors were completely regressed after treatment with a combination of rTNF and rIFN- or rTNF and OK-432. However in all cases, the combination of rTNF at 10³ U/head and any other BRM did not improve the effect. Furthermore, the adverse effects of the combinations were more serious than those of rTNF alone.TNF may still be a useful cytokine, because it can induce the regression of tumors. However, for its clinical application, a method should be developed to reduce its side effects.     

Normal reproductive development of pigs produced using sperm retrieved from immature testicular tissue cryopreserved and grafted into nude mice

Xenografting of immature testicular tissue combined with cryopreservation can preserve and use genetic information of prepubertal animals. For establishment of this new approach, it is essential to clarify whether offspring derived from sperm grown in host mice harboring cryopreserved xenografts show normal reproductive development. This study examined serum profiles of gonadal hormones during sexual maturation in pigs generated by intracytoplasmic sperm injection using sperm derived from cryopreserved xenografts (CryoXeno pigs; three males and three females). We also assessed the reproductive abilities of the male CryoXeno pigs by mating them with conventionally produced (conventional) pigs, and by examining the in vitro fertilizing ability of their sperm. For female CryoXeno pigs, reproductive ability was evaluated by artificial insemination with semen from a conventional boar. During the growth of male CryoXeno pigs, the serum concentrations of inhibin and testosterone showed similar changes (P > 0.17) to those in conventional pigs (n = 4). Histologic analyses of the testes revealed no differences (P > 0.2) in the growth and differentiation of seminiferous tubules between CryoXeno and conventional pigs. Three conventional sows delivered 13.0 ± 1.0 (mean ± standard error of the mean) live piglets after being mated with the three CryoXeno males. Sperm obtained from all CryoXeno pigs had the ability to penetrate oocytes, and these fertilized oocytes reached the blastocyst stage in vitro. During the growth of female CryoXeno pigs, the serum inhibin profile was similar (P > 0.17) to that observed in conventional pigs (n = 5). The first rise in serum progesterone concentration to more than 2 ng/mL was noted at 32.0 ± 2.3 weeks of age in the CryoXeno pigs and at 32.0 ± 3.3 weeks in the conventional pigs, suggesting that both pigs reached puberty at a similar age. After puberty, female CryoXeno pigs farrowed 8.3 ± 1.7 (mean ± standard error of the mean; n = 3) live piglets after artificial insemination with semen from a conventional boar. In conclusion, these findings demonstrate that both male and female CryoXeno pigs have normal reproductive abilities.     

In vivo effects of recombinant human lymphotoxin on human medulloblastoma xenograft: Enhancement of antitumor activity of etoposide

The authors investigated the antitumor activities of rHuLT alone and in combination with etoposide on human medulloblastoma xenografts growing subcutaneously in nude mice. Intravenous administration of rHuLT (1.0×10⁵U/kg, 5.0×10⁵U/kg, 2.5×10⁶U/kg, three times a week for three weeks) suppressed medulloblastoma growth depending on the dose. However, the highest dosage caused serious side effects. Combining rHuLT (intravenously, 5.0×10⁵U/kg, three times a week for three weeks) with etoposide (intraperitoneally, 20mg/kg, once a week for three weeks) increased the antitumor activity without causing serious toxicity. Microscopically, tumor specimen showed thrombosed tumor vessels and massive necrosis 3 weeks after rHuLT treatment. Ultrastructural examination revealed that 120 minutes after the administration of rHuLT alone, disruption of interendothelial junctions was evident, and that the endothelial cells were destroyed at 240 minutes.Concentration of etoposide in tumor tissue peaked 30 minutes after intraperitoneal administration, and then decreased with time. When etoposide was administered in combination with rHuLT, the concentration of etoposide in tumor tissue after 60 to 240 minutes was significantly higher than when etoposide was given alone, and the area under the concentrationversus time curve was also greater for the tumors of mice with combination treatment.The findings suggest that the proper combination of rHuLT and etoposide may have synergistic antitumor activities. Histological changes suggest that increased concentrations of etoposide within the tumor after combination therapy may occur due to increased vascular permeability and/or decreased etoposide clearance which is the result of blood stasis in the tumor vasculature.Abbreviations AUC area under the concentration versus time curve - LT lymphotoxin - rHuLT recombinant human lymphotoxin - rHuTNF recombinant human tumor necrosis factor - TNF tumor necrosis factor     

“Patient-Like” nude mouse metastatic model of advanced human pleural cancer

Pleural Cancer in humans is a frequently occuring tumor, Recently, clinical ltrials have suggested that chemotherapy and immunotherapy administered intrapleually may elicit responses in early-stage diseases. However, atradiological and pleural endoscopic evaluation, most of the patients are found to have a visceral pleural involvement that is generally refractory to therapy and leads to a poor prognosis. The goal of this study was to construct a nude mouse model of human parietal- and visceral-pleural cancer that could reflect the clinical picture for this disease. The model could then be useful for drug discovery for pleural cancer. A well-differentiated human lung adenocarcinoma was used as intact tissue for implantation. Ten mice underwent parietal-pleural implantation and ten mice visceral-pleural implantation via a novel thoracotomy procedure we have developed. Symptoms of tumor growth were determined from weight loss, repiratory distress, or debilitation. Actual tumor growth and spread were measured at autopsy. The mouse survival curves of each group were estimated by the Kaplan-Meier Method and the difference of the median survial timje was assessed by the Log-rank test. The slopes of mean-mouse weight curves were compared using a standard two-sample t-test. 100% take rate was achieved in constructing the pleural cancer models. Tumor growth was initially assessed by symptomatology and survival: the median survival time was, repectively, 27.9 days 31 days for visceral-pleural and parietal-pleural implanted groups (P<0.05). The comparison between the slopes of the mean weight curves of corresponding groups demonstrated that visceral-pleural implanted animals lost significantly more weight than the parietal-pleural implanted animals (P <.001). Both in the visceral- and pariental-pleural implanted groups, post-mortem analysis revealed that tumor grew in all mic demonstrating local and regional spread mimicking clinical features. However, mediastinal lymph node metastases were observed only in mice with visceral pleural implantation. Patient-like models of human parietal-pleural and visceral-pleural cancer were constructed in nude mice using histologically ilntact human specimens. Tumor symptoms, growth, and spread as well as survival indicated that the parietal-pleural and visceral-pleural models represent, respectively, early-and advanced-stage disease. The “Patient-like” nude mouse models of pleural cancer now allow a rational basis for futher studies of pleural cancer biology, pathophysiology, and therapeutics.     

Rapid elimination of mouse/human chimeric monoclonal antibodies in nude mice

 At our laboratory we are currently evaluating the suitability of mouse/human chimeric monoclonal antibodies (cmAb) for use in radioimmunotherapy of patients with head and neck squamous cell carcinoma (HNSCC). We have developed cmAb containing the human constant IgG1 domain and the variable domains of murine mAb (mmAb) E48 and U36 respectively. We considered the tumour-bearing nude mouse to be a well-validated model for a first testing of the targeting capabilities of these cmAb in comparison with the mmAb. Therefore, 3 μg cmAb E48 (labelled with ¹²⁵I) and 3 μg mmAb E48 (labelled with ¹³¹I) were simultaneously injected into HNSCC-bearing nude mice and, at various assay times, mAb uptake in blood and other tissues was assessed. Remarkably, while in roughly 50% of the animals the biodistribution of the conjugates was similar, in the other animals cmAb E48 showed a much higher blood clearance than mmAb E48. This resulted in a lower tumour uptake of cmAb E48 in comparison with mmAb E48. To determine whether this phenomenon was related to mAb E48 or to the animal model, other cmAb-mmAb combinations were evaluated in the same way: cmAbs SF-25, 17-1A and U36 (all IgG1) were tested and all showed a rapid elimination in about 50% of the animals. Besides a decrease in blood concentration, an increase of cmAb levels in liver and spleen was observed within 24 h after injection. Isotype-specific enzyme-linked immunosorbent assays showed that mice that demonstrated a rapid elimination of cmAb from the blood had much lower endogenous IgG1, IgG2b and IgG3 titres than mice showing normal clearance. IgG2a levels were low in all mice. Biodistribution experiments with 3 μg chimeric 17-1A isoforms showed high blood clearance in a proportion of the mice for IgG1, IgG3 and IgG4, but not for IgG2. Increase of the cmAb dose to 100 μg resulted in a similar cmAb and mmAb biodistribution in all mice. Moreover, the biodistribution of the F(ab′)₂ fragment of an IgG1 cmAb was similar for all mice in contrast to that of coinjected whole IgG. On the basis of these results it can be hypothesized that, in mice with low endogenous IgG titres, cmAb with specific isotypes are rapidly removed from the blood (and ultimately from the body) by mediation of Fc-binding receptors. Apparently, in mice with high endogenous IgG titres or in mice receiving a high cmAb dose, these receptors are saturated. Furthermore, the rapid elimination of cmAb from nude mice, which may occur after injection at a low dose, is a phenomenon related to the nude mouse model. Received: 26 July 1996 / Accepted: 16 January 1997     

Expression of the human insulin gene in the gastric G cells of transgenic mice

The goal of this study was to engineer gastrin-producing G cells of the gastric antrum to produce insulin. A pGas-Ins chimeric gene in which the gastrin promoter drives expression of the human insulin gene was constructed and was validated by transient transfection of GH4 and AGS cells. RT-PCR analysis and sequencing revealed three forms of differentially spliced insulin mRNA in GH4 cells transiently transfected by pGas-Ins. Gas-Ins transgenic mice were generated utilizing this chimeric gene. Northern blot analysis, in situ hybridization, and immunohistochemistry demonstrated expression of the human insulin gene specifically in antral G cells. Northern blot analysis demonstrated that the shortest of the insulin mRNA three forms is predominantly expressed in stomach tissue. RT-PCR analysis also showed expression of the transgene in colon, pancreas, and brain tissues that was undetectable by northern analysis. We conclude that gastrin promoter can be used for targeting expression of human insulin to antral G cells and that antral G cells can express human insulin. Further refining of the chimeric gene design is required to enhance expression.     

Identification and characterization of glucocorticoid receptors in liver of nude mice

Glucocorticoids regulate the expression of many liver-specific genes via glucocorticoid receptors. The presence of glucocorticoid receptors in liver has been reported in many mammalian species but not in nude mice. In the present study, we demonstrate the presence of specific glucocorticoid receptors in nude mouse liver. The binding of ligands to these receptors could be completely inhibited by RU486, and partially blocked by hydrocortisone and progesterone, whereas estrogen and testosterone had no effect. Hydrocortisone down-regulated the level of glucocorticoid receptors in livers of nude mice and correspondingly enhanced the activities of tyrosine aminotransferase and -glutamyltransferase. Our results indicate that glucocorticoid receptors in nude mouse liver are specific, fully functional, and present at levels 28.5-fold higher than in the liver of normal inbred mice. We suggest that the nude mouse is a valuable model for studies of hepatic glucocorticoid action and may provide a clue to a putative hepatic-thymic interaction.     

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。     

Regorafenib regresses an imatinib-resistant recurrent gastrointestinal stromal tumor (GIST) with a mutation in exons 11 and 17 of c-kit in a patient-derived orthotopic xenograft (PDOX) nude mouse model

Gastrointestinal stromal tumor (GIST) with a mutation in exons 11 and 17 of c-kit is a rare type of sarcoma. The aim of this study was to determine drug sensitivity for a regionally-recurrent case of GIST using a patient-derived orthotopic xenograft (PDOX) model. The PDOX model was established in the anterior wall of the stomach. GIST PDOX models were randomized into 5 groups of 6 mice each when the tumor volume reached 60 mm³: G1, control group; G2, imatinib group (oral administration (p.o.), daily, for 3 weeks); G3, sunitinib group (p.o., daily, for 3 weeks); G4, regorafenib (p.o., daily, for 3 weeks); G5, pazopanib (p.o., daily, for 3 weeks). All mice were sacrificed on day 22. Tumor volume was evaluated on day 0 and day 22 by laparotomy. Body weight were measured 2 times per week. Though regorafenib is third-line therapy for GIST, it was the most effective drug and regressed the tumor significantly (p < 0.001). Sunitinib suppressed tumor growth compared to the control group (p = 0.002). Imatinib, first-line therapy for GIST, and pazopanib did not have significant efficacy compared to the control group (p = 0.886, p = 0.766). The implications of this result is discussed for GIST patients.     

Morphological and functional evaluation of angiogenesis of a xenografted human sarcoma in nude mice

The implantation of tumour cells in normal tissues and the subsequent induction of angiogenesis by the growing xenograft were studied by means of immunohistochemistry and digital image analysis. Tumour growth was induced by injection of a human spindle cell sarcoma (ES3) into the subcutis of HsdCpb:NMRI-nu/nu mice. In vivo injection of Hoechst 33342 was used as a marker of perfusion. The vasculature was stained with specific antibodies and subsequently analysed by digital image analysis. Starting at day 3 up to day 6, angiogenesis could be detected and the relative amount of perfusion within the investigated area reached a peak at day 6. This method, which allows investigation of both functional and morphometric characteristics of human xenograft vasculature, serves as an excellent assay for evaluation of antiangiogenic therapies in translational research of experimental tumours.     

Occurrence and morphology of tumors induced in nude mice transplanted with chrysotile-transformed rat pleural mesothelial cells

Rat pleural mesothelial cells treated in vitro with chrysotile fibers have been successfully transplanted into nude mice. Three cultures (1 untreated, 2 treated) were injected at passage 75; a fourth culture was obtained from a mesothelioma induced in rat by chrysotile fibers. Overall, tumors grew in each series, but the delay between cell injection and tumor formation was 22 wk with untreated cells whereas only 1 or 2 wk were needed with treated cells, and 1 wk with cells from in vivo-induced mesothelioma. Pathological study by light and electron microscopy of tumors is reported here and showed the mesothelial nature of the cells. Comparison between the ultrastructure of the injected cells and tumor cells indicated that the morphology of injected cells was retained in tumors even if the delay in tumor formation was long. These results suggest that this model is useful for investigating mesothelial cell transformation resulting from in vitro or in vivo exposure to certain carcinogens.     

人胃癌细胞株裸鼠皮下移植瘤模型的建立及其生物学特性

目的初步建立不同浓度下制备人胃癌细胞株BGC-823裸鼠皮下移植瘤模型,观察其生物学特性。方法培养人胃癌细胞系BGC-823细胞,并分别以四个浓度皮下注射于裸鼠腋下每只0.2 mL。根据BGC-823细胞注射浓度将40只裸鼠随机分为四组：组一5×107个活细胞/mL（n=10）;组二1×107个活细胞/mL（n=10）;组三1×106个活细胞/mL（n=10）;组四1×105个活细胞/mL（n=10）。观察各组裸鼠摄食、活动情况、精神状态、死亡率、成瘤时间、成瘤率、肿瘤生长情况,采用免疫组化法检测肿瘤微血管密度。结果各组裸鼠摄食、精神情况正常,无死亡现象。除组四1×105个活细胞/mL浓度组成瘤率为0%外,其余各组成瘤率均为100%,瘤体出现时间在3～7 d,肿瘤血管密度MVD平均为：（123.26±31.57）个/mm2。结论初步建立了人胃癌裸鼠皮下移植瘤模型及建立此细胞系模型的最低浓度。为胃癌的进一步研究奠定了基础。     

Antitumour activity of a sterically blocked ricin immunotoxin on a human colorectal adenocarcinoma grafted subcutaneously in nude mice

Summary We prepared a ricin-antibody conjugate, lacking the ability to bind the galactosidic residues of Sepharose 6B, a so-called blocked immunotoxin. The monoclonal antibody AR-3 was cross-linked to ricin through a thioether bond. Further studies showed that the immunoconjugate suppressed the tumour growth of HT-29 cells in intraperitoneally grafted nude mice, without showing any undesirable ricin toxicity.In this work, to demonstrate the therapeutic activity of the AR-3—ricin conjugate injected into mice bearing subcutaneous tumour, we first evaluated its pharmacokinetic behaviour and biodistribution. The behaviour of the immunoconjugate injected intravenously was almost intermediate between that of the antibody and ricin. Moreover, when the immunotoxin was intravenously administered to nude mice bearing subcutaneous tumour, no therapeutic effects appeared, in accordance with the relatively low permeability of the immunotoxin from the blood to the skin. In contrast, peritumoral treatment produced a strong reduction of the neoplastic nodules without substantial regrowth of the malignant cells. This result was also achieved when the immunotoxin treatment was performed on a well-established tumour. This finding was strictly related to the specificity of the immunoconjugate, since the analogous treatment with an irrelevant immunotoxin showed therapeutic failure.     

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.     

siRNA blocking the RAS signalling pathway and inhibits the growth of oesophageal squamous cell carcinoma in nude mice

The aim of this study was to study RAS‐siRNA blocking RAS pathway and suppressing cell growth in human oesophageal squamous cell carcinoma in nude mice. The methods in this study was to construct RAS‐siRNA expression vector, establish 40 oesophageal squamous cell carcinoma xenograft animal models and divided them into five groups: control group, siRNA control group, RAS‐siRNA group, paclitaxel group and RAS‐siRNA and paclitaxel group. We observed tumour growth in nude mice, studied histology by HE staining, tumour growth inhibition by TUNEL assay and detected the RAS, MAPK and cyclin D1 protein expression by immunohistochemistry and western blot. We have obtained the following results: (i) successfully established animal models; (ii) nude mice in each group after treatment inhibited tumour volume was significantly reduced compared with the control group (p < 0.05); (iii) compared with the control group, the number of apoptotic cells were significantly increased in the siRNA control group and the RAS‐siRNA group, and the number of apoptosis cells in the paclitaxel and RAS‐siRNA group is significantly most than the paclitaxel group and RAS‐siRNA group (p < 0.05); and (iv) after treatment, RAS, MAPK and cyclin D1 expression in five groups was decreasing gradually. After adding paclitaxel, the protein expression in the paclitaxel and RAS‐siRNA group was significantly lower than that of paclitaxel group, negative control and paclitaxel group (p < 0.05). We therefore conclude that RAS‐siRNA can block the RAS signal transduction pathway, reduce the activity of tumour cells, arrest tumour cell cycle, promote apoptosis, inhibit cell proliferation and increase tumour cell sensitivity to chemotherapeutic drugs. Copyright © 2014 John Wiley & Sons, Ltd.